JP7442374B2 - Dirt detection device, paper sheet processing device, dirt detection method and program - Google Patents

Description

The present invention relates to a stain determination device that determines stains on paper sheets, and related techniques.

BACKGROUND ART Conventionally, there exists a technique for determining dirt on paper sheets such as banknotes. For example, Patent Documents 1 and 2 describe a technique of irradiating paper sheets with light emitted from a visible light source and using reflected light from the paper sheets to determine the degree of dirt on banknotes. There is.

Japanese Patent Application Publication No. 2010-039765 Japanese Patent Application Publication No. 2010-277252

However, in the above-mentioned technique that uses the reflected light from a visible light source on a paper sheet to determine the degree of contamination, it is difficult to determine the presence or absence of minute degrees of contamination. For example, when a visible light source is used as a light source, reflected light from completely new banknotes (official tickets, etc.) and banknotes that are slightly soiled due to body fluids such as saliva and/or hand grime (visually clean). The difference in intensity from the reflected light from the banknotes is small. Therefore, it is difficult to accurately distinguish between the former banknotes (official tickets, etc.) and the latter banknotes (visually clean banknotes) based on the degree of dirt. In other words, it is difficult to accurately grasp the degree of dirt on the latter banknote.

Therefore, an object of the present invention is to provide a technique that can realize highly accurate determination regarding stains on paper sheets.

In order to solve the above problems, a stain determination device according to the present invention includes a light emitting section that irradiates excitation light onto paper sheets to generate fluorescence on the paper sheets, and a light emitting section that receives the fluorescence generated on the paper sheets. and a first light receiving intensity that is the light receiving intensity of fluorescence generated from a first region within the paper sheet to which fluorescent ink is not originally applied and received by the light receiving section. and a control unit that determines whether the paper sheet is soiled based on the following.
The control unit specifies a first area within the paper sheet that is not originally coated with fluorescent ink, distinguishing it from an area that is originally coated with fluorescent ink, and The dirt on the paper sheet may be determined based on the first received light intensity, which is the received light intensity of the fluorescence generated from the first area and received by the light receiving section.

The control unit may determine the degree of dirt on the paper sheet by determining the degree of dirt on the paper sheet.

The control unit may determine whether the paper sheet is soiled by determining whether or not the paper sheet is soiled.

The control unit may determine that the greater the first received light intensity, the greater the degree of dirt on the paper sheet.

The control unit may determine that the paper sheet is dirty when the first received light intensity is greater than a predetermined reference value.

The control unit is configured to detect fluorescence that is generated from a second area where it is estimated that dirt is less likely to be detected than the first area and is not originally coated with fluorescent ink and is received by the light receiving unit. The soiling of the paper sheet may be determined based on the second received light intensity, which is the received light intensity, and the first received light intensity.

The control section is configured to control a second received light intensity that is a received light intensity of fluorescence generated from a second region, which is a reference region that originally exhibits a certain level of fluorescence reaction, and is received by the light receiving section, and the first received light intensity. The soiling of the paper sheet may be determined based on the following.

The second area may be a different area from the first area within the paper sheet.

The second area may be a predetermined area provided on a predetermined member within the dirt determination device.

The control unit is configured to detect fluorescence that is generated from a second area where it is estimated that dirt is less likely to be detected than the first area and is not originally coated with fluorescent ink and is received by the light receiving unit. The dirt on the paper sheet may be determined based on the difference between the second received light intensity, which is the received light intensity, and the first received light intensity.
The control unit may determine that the greater the difference between the first received light intensity and the second received light intensity, the greater the degree of dirt on the paper sheet.

The control unit may determine that the paper sheet is dirty when the difference between the first received light intensity and the second received light intensity is larger than a predetermined value.

The control section is configured to control a second received light intensity that is a received light intensity of fluorescence generated from a second region, which is a reference region that originally exhibits a certain level of fluorescence reaction, and is received by the light receiving section, and the first received light intensity. The soiling of the paper sheet may be determined based on the difference.
The control unit may determine that the smaller the difference between the first received light intensity and the second received light intensity, the greater the degree of dirt on the paper sheet.

The control unit may determine that the paper sheet is dirty when the difference between the first received light intensity and the second received light intensity is smaller than a predetermined value.

The difference may be a difference between the first received light intensity and the second received light intensity, or a ratio between the first received light intensity and the second received light intensity.

The first received light intensity and the second received light intensity may be received light intensities of fluorescence in a specific wavelength range.

The first received light intensity is the received intensity of fluorescence in a first wavelength range, and the second received light intensity is the received intensity of fluorescence in a second wavelength range, and the first wavelength range and the second wavelength range are different from each other. may be in different wavelength ranges.

The control unit is configured to control a first intensity that is a received intensity of light in a first wavelength range among the fluorescence from the first region, and a second wavelength different from the first wavelength range among the fluorescence from the first region. The soiling of the paper sheet may be determined based on the difference from the second intensity which is the received light intensity of the area.

The control unit is configured to control a first intensity that is a received intensity of light in a first wavelength range among the fluorescence from the first region, and a second wavelength different from the first wavelength range among the fluorescence from the first region. a third intensity that is the received intensity of light in the first wavelength range among the fluorescence from the second area; The soiling of the paper sheet may be determined based on a second difference between a fourth intensity that is a received intensity of light in the second wavelength range among the fluorescence from the area.

The first wavelength range may be a green wavelength range, and the second wavelength range may be a red wavelength range.

The first area may be a patternless area within the paper sheet.

The first area may be a watermark area within the paper sheet.

A paper sheet processing apparatus according to the present invention is characterized by comprising a stain determination device having any of the above characteristics.

Further, in the stain determination method according to the present invention, a) a computer distinguishes a first area in a paper sheet to which fluorescent ink is not originally applied from an area to which fluorescent ink is originally applied; b) the computer obtains a first received light intensity that is the received light intensity of fluorescence generated from the first region in response to irradiation of the excitation light onto the paper sheet; c) The method is characterized in that the computer comprises a step of determining whether the paper sheet is soiled based on the first received light intensity.
Further, the stain determination method according to the present invention includes: a) a first area in the paper sheet that is not originally coated with fluorescent ink; a first received light intensity that is the received light intensity of fluorescence generated from the second area, and a second area where it is estimated that dirt is less likely to be detected than the first area and which is not originally coated with fluorescent ink. a step in which the computer acquires a second received light intensity that is the received light intensity of the generated fluorescence; b) the computer detects dirt on the paper sheet based on the difference between the first received light intensity and the second received light intensity; The method is characterized by comprising a step of making a determination regarding.
Further, the stain determination method according to the present invention includes: a) a first area in the paper sheet that is not originally coated with fluorescent ink; The computer acquires the first received light intensity, which is the received light intensity of the fluorescence generated from the second region, which is the received light intensity of the fluorescence generated from the second region, which is originally the reference region that shows a certain degree of fluorescence reaction. and b) the computer determines whether the paper sheet is soiled based on the difference between the first received light intensity and the second received light intensity.
Further, the stain determination method according to the present invention includes: a) a first area in the paper sheet that is not originally coated with fluorescent ink; b) a step in which the computer determines whether the paper sheet is soiled based on the first received light intensity; In step b), b-1) the computer receives a first intensity that is a received light intensity of light in a first wavelength range among the fluorescence from the first region; The present invention is characterized by comprising a step of determining whether the paper sheet is soiled based on a difference from a second intensity that is a received light intensity of light in a second wavelength range different from the wavelength range.
Further, the stain determination method according to the present invention includes: a) a first area in the paper sheet that is not originally coated with fluorescent ink; a first received light intensity that is the received light intensity of fluorescence generated from the second area, and a second area where it is estimated that dirt is less likely to be detected than the first area and which is not originally coated with fluorescent ink. a step in which the computer obtains a second received light intensity that is the received light intensity of the generated fluorescence; b) the computer determines whether the paper sheet is soiled based on the first received light intensity and the second received light intensity; The step b) comprises b-1) a first intensity that is the received intensity of light in a first wavelength range among the fluorescence from the first region, and a first intensity of the fluorescence from the first region. A first difference is a difference between the received intensity of light in a second wavelength range different from the first wavelength range, and a first difference is a difference between the received intensity of light in a second wavelength range different from the first wavelength range; Based on the third intensity, which is the received light intensity, and the second difference, which is the difference between the fourth intensity, which is the received light intensity of the light in the second wavelength range among the fluorescence from the second region, the computer The method is characterized by comprising a step of determining whether the leaves are soiled.
Further, the stain determination method according to the present invention includes: a) a first area in the paper sheet that is not originally coated with fluorescent ink; The computer acquires the first received light intensity, which is the received light intensity of the fluorescence generated from the second region, which is the received light intensity of the fluorescence generated from the second region, which is originally the reference region that shows a certain degree of fluorescence reaction. and b) the computer determines whether the paper sheet is soiled based on the first received light intensity and the second received light intensity, and the step b) includes b-1). A first intensity that is the received intensity of light in a first wavelength range among the fluorescence from the first region, and reception of light in a second wavelength range different from the first wavelength range among the fluorescence from the first region. a first difference, which is the difference between the second intensity, which is the intensity; a third intensity, which is the received intensity of the light in the first wavelength range among the fluorescence from the second region; and a third intensity, which is the received intensity of the light in the first wavelength range among the fluorescence from the second region; The present invention is characterized by comprising a step in which the computer determines whether the paper sheet is soiled based on a second difference that is a difference from a fourth intensity that is the received light intensity of the light in the second wavelength range.

Further, a program according to the present invention is characterized in that it is a program for causing a computer to execute a stain determination method having any of the above characteristics.

According to the present invention, dirt on the paper sheet is determined based on the first received light intensity, which is the received light intensity of fluorescence from the first region where fluorescent ink is not originally applied. Therefore, it is possible to realize highly accurate determination regarding dirt on paper sheets.

It is a perspective view showing the appearance of a paper sheet processing device. FIG. 1 is a block diagram showing a schematic configuration of a paper sheet processing device. FIG. 1 is a vertical cross-sectional view schematically showing a schematic configuration of a dirt determination device. FIG. 3 is a diagram of the upper unit (line sensor unit) viewed from below. FIG. 2 is a schematic diagram showing the configuration, etc. inside a pixel unit. It is a figure which shows the image etc. which were photographed by illuminating a banknote with a visible light source. It is a figure which shows the image etc. regarding the fluorescence generated by irradiating a banknote with excitation light. It is a figure which shows the image etc. regarding the fluorescence generated by irradiating a banknote with excitation light. It is a figure which shows the image etc. regarding the fluorescence generated by irradiating a banknote with excitation light. It is a figure which shows the image etc. regarding the fluorescence generated by irradiating a banknote with excitation light. FIG. 6 is a diagram illustrating an example of classification regarding degree of contamination. FIG. 3 is a conceptual diagram showing changes in differences. It is a conceptual diagram which shows the detection result regarding two banknotes in a simplified form. FIG. 3 is a longitudinal cross-sectional view also showing a plate-like member and the like inside the line sensor unit. FIG. 15 is a view of the upper unit of FIG. 14 viewed from below. FIG. 3 is a conceptual diagram showing changes in differences. FIG. 3 is a longitudinal cross-sectional view also showing a fluorescent screen and the like inside the line sensor unit. FIG. 18 is a view of the upper unit of FIG. 17 viewed from below. FIG. 3 is a conceptual diagram showing changes in differences. FIG. 3 is a conceptual diagram showing changes in differences. FIG. 3 is a conceptual diagram showing changes in differences. It is a flowchart which shows the process in the control part of a dirt determination apparatus.

Embodiments of the present invention will be described below based on the drawings. In addition, in this application, "fluorescence" means light emission (fluorescence in a broad sense) produced by irradiation with excitation light. In particular, "fluorescence" in this application refers to fluorescence (in the narrow sense), which has a short lifetime (nearly no fluorescence) in which light emission continues after the excitation light (light for excitation) is stopped, and phosphorescence, which has a long lifetime and has an afterglow. This shall include any of the following.

<1. First embodiment>
<Overview of paper sheet processing equipment>
FIG. 1 is a perspective view showing the appearance of the paper sheet processing device 10, and FIG. 2 is a block diagram showing the schematic configuration of the paper sheet processing device 10. As shown in FIG. Here, as the paper sheet processing apparatus 10, a banknote processing apparatus, more specifically, a small banknote processing apparatus installed on a table and utilized is illustrated. Moreover, although banknotes are mainly illustrated as paper sheets here, the paper sheets are not limited thereto, and may be gift certificates, checks, securities, and/or other card-like media.

The paper sheet processing device 10 includes a paper sheet identification device 20 (see FIG. 2) that performs paper sheet identification processing (specifically, identification processing regarding the type of paper sheet, authenticity, and/or dirt, etc.). ). The paper sheet identification device 20 is arranged (built-in) inside the casing 19 of the paper sheet processing device 10 . The paper sheet identification device 20 is a device that also performs determination processing regarding dirt on paper sheets, as will be described in detail later, and is also referred to as a dirt determination device.

Further, as shown in FIG. 1, the paper sheet processing apparatus 10 includes an operation section 13, a display section 15, a hopper 11, a plurality of (here, two) reject sections 12, and a plurality of (here, four) stackers. 16.

The operation unit 13 includes a plurality of buttons and the like. The operation unit 13 is an operation input unit for inputting instructions from an operator using the plurality of buttons and the like. The display unit 15 includes a liquid crystal display and the like. The display section 15 displays information such as the identification and counting results of paper sheets and the stacking status of each stacker section 16.

In the paper sheet processing device 10, classification processing (also referred to as arrangement processing) and the like are performed on a plurality of paper sheets. First, a plurality of paper sheets to be processed are placed in a stacked state in the hopper 11 . Thereafter, the paper sheets fed out one by one from the hopper 11 are conveyed to the paper sheet identification device 20 inside the housing 19, and the paper sheet identification device 20 sequentially performs identification processing on the plurality of paper sheets. It is applied to Then, the plurality of paper sheets are classified based on the identification results of the paper sheet identification device 20 and the like. Specifically, the plurality of paper sheets are respectively stored in the paper sheet identification device 20 among the plurality of ejection sections (also referred to as storage sections) including the plurality of reject sections 12 and the plurality of stacker sections 16. It is discharged to a discharge section according to the identification result, etc. As a result, the plurality of paper sheets are stored in the plurality of discharge sections in a sorted state.

For example, when it is determined that the paper sheet fed into the housing 19 from the hopper 11 is a rejected banknote such as a counterfeit banknote, the rejected banknote is discharged to the reject section 12 . In addition, in the plurality of stacker units 16, the paper sheets (banknotes, etc.) that are determined to be genuine notes by the paper sheet identification device 20 are checked for their type (denomination in the case of banknotes) and/or dirt They are classified and accumulated based on the determination results (also referred to as identification results) and the like. Specifically, banknotes determined to be "dirty" are stored in one of the four stacker units 16, and banknotes determined to be "uncontaminated" are stored in the other three stacker units 16. 16 are classified and stored by denomination. Alternatively, each paper sheet may be sorted and stored in a plurality of stacker sections 16 based on the degree of soiling of the paper sheet (and denomination, etc.).

However, the present invention is not limited to this, and paper sheets determined to be counterfeit bills or bills of uncertain authenticity may be returned to the reject section 12 or may be stored in any of the stacker sections 16. Furthermore, paper sheets (genuine bills, etc.) that are determined to be "dirty" may be discharged to one (or both) of the two reject sections 12.

Further, as shown in FIG. 2, the paper sheet processing apparatus 10 also includes a conveyance section 30 and a control section 40.

The conveyance unit 30 includes a conveyance roller for conveying paper sheets, a drive mechanism (a drive source and a driving force transmission mechanism), etc. that drives the conveyance roller.

The control unit 40 is configured as a computer system including a CPU (Central Processing Unit) and the like, like the control unit 70 (described later) of the dirt determination device 20. Note that the control section 40 of the paper sheet processing device 10 is also referred to as a main body control section or an overall control section to distinguish it from the control section 70 of the stain determination device 20.

The control unit 40 controls various processing units by executing a predetermined software program stored in a storage unit 60 (or a storage unit provided separately from the storage unit 60), which will be described later, in its CPU. Realize. Specifically, as shown in FIG. 2, the control unit 40 implements various processing units including an operation control unit 41, a display control unit 42, and a conveyance control unit 43 by executing the software program. The operation control unit 41 is a processing unit that controls operation input processing and the like in the operation unit 13, and the display control unit 42 is a processing unit that controls display processing and the like in the display unit 15. Further, the conveyance control section 43 is a processing section that controls the conveyance of paper sheets by the conveyance section 30 and the like. For example, the conveyance control unit 43 uses the drive mechanism of the conveyance unit 30, etc. to carry out conveyance processing of paper sheets (conveyance processing to the stain determination device 20, conveyance processing within the stain determination device 20, and conveyance processing to the stain determination device 20 (classification processing (classification transport processing), etc.) based on the determination result.

<Overview of paper sheet identification device (stain determination device) 20>
Next, a schematic configuration of the stain determination device 20 will be described.

As shown in FIG. 2, the dirt determination device 20 includes a line sensor unit 50, a storage section 60, and a control section (also referred to as a controller) 70. The stain determination device 20 also includes a conveyance roller for conveying paper sheets within the stain determination device 20. The conveyance roller in the dirt determination device 20 is driven by the above-described conveyance control section 43, the drive mechanism of the conveyance section 30, and the like. Note that the present invention is not limited to this, and the conveyance roller in the dirt determination device 20 may be driven by a conveyance control section (not shown) in the control section 70 or the like.

The line sensor unit 50 acquires images related to paper sheets conveyed by the conveyance section 30.

The stain determination device 20 includes an upper unit 50a as a line sensor unit 50 for reading the upper surface of paper sheets (more specifically, an image of the upper surface), and an upper unit 50a for reading the upper surface of paper sheets (more specifically, an image of the lower surface). and a lower unit 50b for reading. Thereby, the stain determination device 20 can read both sides of paper sheets (banknotes, etc.) at the same time. Note that the stain determination device 20 is not limited to this, and may be configured to read only one side of paper sheets (banknotes, etc.).

The storage unit 60 includes various semiconductor memories (RAM and ROM) and the like. The storage unit 60 includes a volatile storage device (e.g., semiconductor memory for temporary storage (RAM, etc.)) and a non-volatile storage device (e.g., non-volatile memory (ROM, etc.), hard disk). .

The control unit 70 is a control device (also referred to as a controller) that is built into the dirt determination device 20 and controls the dirt determination device 20. Since the control section 70 is a processing section that controls the stain determination device 20 (sheet identification device 20), it is also referred to as a stain determination control section or an identification control section.

The control unit 70 is configured as a computer system including a CPU (Central Processing Unit) (also referred to as a microprocessor, hardware processor, etc.). The control unit 70 realizes various processing units by executing a predetermined software program (hereinafter also simply referred to as a program) stored in the storage unit 60 in the CPU. Note that the program (specifically, the program module group) may be recorded on a portable recording medium such as a USB memory, read from the recording medium, and installed in the stain determination device 20. Alternatively, the program may be downloaded via a communication network or the like and installed in the stain determination device 20.

Specifically, as shown in FIG. 2, the control unit 70 implements various processing units including a light source control unit 71, an image data generation unit 72, and a determination unit 73 by executing the program.

The light source control unit 71 is a processing unit that controls lighting and extinguishing of each light source of the light emitting unit 52 (see FIG. 3).

The image data generation section 72 is a processing section that generates image data of paper sheets based on the intensity of light received by the light receiving section 55 (see FIG. 3). The image data generation unit 72 generates image data of paper sheets (visible light image data, etc.) based on the received light intensity of the reflected light reflected by the paper sheets among the light from the visible light source. In addition, the image data generation unit 72 generates a signal based on the intensity of the received fluorescence generated on the paper sheet and received by the light receiving unit 55 in response to the excitation light irradiation from the excitation light irradiation light source (for example, a UV light source). Generate image data (also referred to as fluorescent image data) of paper sheets.

For example, the process of generating visible light image data in response to irradiation with a visible light source and the process of generating fluorescence image data in response to irradiation with excitation light are performed on paper sheets (such as banknotes 90 (see FIG. 3)). is repeated alternately for each scan line. Specifically, these two types of processing are repeated for a plurality of scanning lines while the paper sheet is being transported in the transport direction (sub-scanning direction). In other words, the process of alternately acquiring two types of line-shaped images is repeated. As a result, two types of image data (visible light image data and fluorescent image data) regarding a two-dimensional area of the paper sheet are generated almost simultaneously. Note that the visible light image data is generated as data including, for example, infrared light image data. However, the present invention is not limited to this, and the visible light image data may be generated as data that does not include infrared light image data. Moreover, infrared light image data may be generated independently as data separate from visible light image data.

The determination unit 73 is a processing unit that executes determination processing regarding stains on paper sheets. As will be described in detail later, the determination unit 73 determines whether the paper sheet is soiled based on the received intensity of fluorescence (fluorescence image data, etc.) generated from a certain area C1 (described later) within the paper sheet.

<Detailed configuration of dirt determination device 20>
FIG. 3 is a vertical cross-sectional view schematically showing a schematic configuration of the stain determination device 20. As shown in FIG. FIG. 3 shows the dirt determination device 20 cut at a cross section perpendicular to the transport surface (horizontal surface) of banknotes 90 (and along the transport direction), and the cross section is viewed from the direction (side) perpendicular to the cross section. It is a schematic diagram. Banknotes 90 are an example of paper sheets to be processed.

As shown in FIG. 3, a gap 39 of approximately several mm (for example, 1 mm to 3 mm) is provided between the lower surface of the casing 51 of the upper unit 50a and the upper surface of the casing 51 of the lower unit 50b. ing. The banknote 90 passes through the gap 39 and moves in the transport direction (left-right direction in the figure).

Each line sensor unit 50 (upper unit 50a and lower unit 50b) includes a light emitting section 52, a condensing lens 53, a light receiving section 55, and a substrate 57 within a housing 51. The upper unit 50a and the lower unit 50b have the same configuration. The lower unit 50b has a configuration in which the upper unit 50a is upside down, and is disposed upstream (or downstream) of the upper unit 50a in the transport direction.

The light emitting unit 52 includes a white light source that emits visible light and a UV light source (ultraviolet light source) that emits excitation light. The white light source is a light source that emits light in the visible wavelength range (400 nm to 700 nm). The white light source may emit only light in the visible wavelength range (400 nm to 700 nm), or may also emit light in the infrared wavelength range (700 nm to 1000 nm). Here, a white light source that emits light in both visible light wavelength ranges and infrared light wavelength ranges is employed. Further, the UV light source is a light source that emits light in the wavelength range of ultraviolet light (10 nm to 400 nm (for example, 300 nm to 400 nm)). Here, a UV light source that irradiates ultraviolet light (UV light) is exemplified as a light source that irradiates the banknote 90 with excitation light to generate fluorescence in the banknote 90 (paper sheet). In other words, ultraviolet light is exemplified as the excitation light.

The white light source and the UV light source (ultraviolet light source) may be turned on at different timings. For example, a white light source is turned on when acquiring image data regarding visible light, and a UV light source is turned on when acquiring image data regarding fluorescence. More specifically, for each scanning line within the banknote 90, a white light source and a UV light source are alternately turned on at minute time intervals. By repeating such an operation for a plurality of scanning lines (main scanning lines), visible light image data of the banknote 90 and fluorescence image data of the banknote 90 are generated almost simultaneously. However, the present invention is not limited thereto, and visible light image data may be acquired by, for example, conveying the bill 90 in the sub-scanning direction while only the visible light source is always turned on. Further, the fluorescence image data may be acquired by conveying the banknote 90 in the sub-scanning direction while only the UV light source (ultraviolet light source) is always turned on.

The light emitting section 52 is arranged to extend linearly in the horizontal direction (specifically, in the direction perpendicular to the paper surface of FIG. 3). Specifically, the light emitting section 52 is configured to include a light source (such as an LED) disposed at both ends (or one end) in the extension direction and a linear light guide that guides light from the light source. Ru. The light guided from the light source to the light guide in the light emitting unit 52 is emitted toward the conveyance path of the banknote 90 from each position (each horizontal position) in the extending direction of the light guide. Specifically, the light has directivity in a predetermined direction (the direction of the black arrow in FIG. 3) in a plane perpendicular to the extending direction of the light emitting part 52 (in the paper plane of FIG. 3), and It progresses to a predetermined linear area on the conveyance surface.

As shown in FIG. 4, the light emitting section 52 is arranged so as to extend over a wider range than the width of the banknote (the length in the direction perpendicular to the transport direction on the transport surface). Note that FIG. 4 is a diagram of the upper unit 50a viewed from below. In FIG. 4, illustration of the light receiving section 55, the substrate 57, etc. is omitted.

The light receiving section 55 includes a line sensor (a group of light receiving elements) extending one-dimensionally (in a line shape), and the like. The light receiving section 55 is fixed to a substrate 57 (FIG. 3). Similarly to the light emitting section 52, the light receiving section 55 is also disposed to extend linearly in a direction perpendicular to the paper surface of FIG. The light receiving section 55 is provided substantially parallel to the light emitting section 52.

A line sensor is composed of a plurality of (for example, 1600) pixel units arranged in a line. The pixel unit has four light receiving elements 56B, 56R, 56G, and 56I (see FIG. 5). FIG. 5 is a schematic diagram showing the configuration inside the pixel unit.

The four light receiving elements 56B, 56R, 56G, and 56I each have a bandpass filter that transmits only a specific wavelength range. As a result, each of the light receiving elements 56B, 56R, 56G, and 56I receives light in a corresponding specific wavelength range.

The light receiving element 56B has a bandpass filter 54B that transmits blue light (light in a wavelength range of approximately 400 nm to 500 nm), and receives the blue light. The light-receiving element 56G includes a bandpass filter 54G that transmits green light (light in a wavelength range of approximately 500 nm to 600 nm), and receives green light. The light-receiving element 56R includes a bandpass filter 54R that transmits red light (light in a wavelength range of approximately 600 nm to 700 nm), and receives red light. Further, the light receiving element 56I includes a bandpass filter 54I that transmits infrared light (light in a wavelength range of approximately 700 nm to 1000 nm), and receives infrared light (IR light).

The light-receiving element 56R has a bandpass filter that transmits both red light and infrared light, so that it can transmit red light (light in the wavelength range of approximately 600 nm to 700 nm) and infrared light (light in the wavelength range of approximately 700 nm to 1000 nm). It is also possible to receive both light. Further, in FIG. 5, the four light receiving elements 56B, 56R, 56G, and 56I are arranged two in each direction (in a grid pattern), but the invention is not limited to this. For example, the four light receiving elements 56B, 56R, 56G, and 56I may be arranged in a line along the transport direction, or may be arranged in a line in a direction perpendicular to the transport direction.

When light from a white light source is emitted from the light emitting section 52, the light passes through the light transmitting section 58 (FIG. 2) made of transparent resin (or transparent glass, etc.), is reflected by the banknote 90, and is then collected. The light is focused by the optical lens 53 and received by the light receiving section 55. Specifically, the light receiving elements 56B, 56R, 56G, and 56I of the light receiving section 55 each receive light in a specific wavelength range. Then, a value corresponding to the intensity of light received by each light receiving element (amount of light received) is sent from the light receiving unit 55 as a pixel value (in detail, a pixel value for each color component (wavelength range component)) of that pixel unit. Output. In other words, each output value (pixel value for each color component) from the light receiving elements 56B, 56R, 56G, and 56I in a certain pixel unit is determined by the received light intensity (details) of the reflected light from the corresponding position in the banknote 90. is obtained as a detected value (measured value) of the received light intensity for each wavelength range.

Furthermore, as described above, the light emitting section 52 can also emit light from a UV light source instead of a white light source. The UV light source is a light source that emits ultraviolet light (UV light). When paper sheets are irradiated with the ultraviolet light (UV light) as excitation light, fluorescence is generated from the paper sheets.

When light from a UV light source is emitted from the light emitting section 52, the light (UV light) passes through the light transmitting section 58 made of transparent resin (or transparent glass, etc.) and reaches the banknote 90. Then, the UV light changes to fluorescence on the surface of the banknote 90. That is, fluorescence is generated from the surface of the banknote 90. The fluorescence is collected by a condensing lens 53 and received by a light receiving section 55. Specifically, the light receiving elements 56B, 56R, 56G, and 56I of the light receiving section 55 each receive light in a specific wavelength range. Then, a value corresponding to the intensity of light received by each light receiving element (amount of light received) is output from the light receiving section 55 as a pixel value of that pixel unit (specifically, a pixel value for each color component). In other words, each output value (pixel value for each color component) from the light-receiving elements 56B, 56R, 56G, and 56I in a certain pixel unit is determined by the received light intensity of "fluorescence" from the corresponding position in the banknote 90 ( Specifically, it is acquired as a detected value (measured value) of the received light intensity for each wavelength range.

In addition, a line sensor uses pixel values (in detail, pixel values for each color component) of multiple pixel units arranged one-dimensionally (in a line) along the main scanning direction (perpendicular to the transport direction). ) are obtained almost simultaneously. In other words, the line sensor acquires an image of a line-shaped area within the banknote 90 (specifically, each line-shaped image regarding each of a plurality of color components) within a minute time. Then, while the banknote 90 is being conveyed in the sub-scanning direction (conveyance direction), similar image acquisition processing of the line-shaped area is repeated. As a result, an image (two-dimensional color image) regarding the two-dimensional area of the banknote 90 is obtained.

Specifically, when the banknote 90 is irradiated with light from a white light source, the line sensor detects the received light intensity (pixel value) of the reflected light from each position within the two-dimensional area of the banknote 90 using the color component (wavelength range). Separate components). In other words, a two-dimensional color image (a two-dimensional color image of reflected light on the banknote 90) corresponding to visible light irradiation is obtained.

In addition, when the banknote 90 is irradiated with light (excitation light) from a UV light source (excitation light source), the line sensor detects the received light intensity (pixel value) for each color component (component by wavelength range). In other words, a two-dimensional color image (a two-dimensional color image of "fluorescence" on the banknote 90) corresponding to the excitation light irradiation is acquired.

<Banknote 90>
Next, the banknote 90 will be explained.

FIG. 6 is a diagram showing information regarding an image (visible light image) captured by illuminating the banknote 90 with a visible light source. The upper image in FIG. 6 is an image captured by illuminating the bill 90 with a visible light source. Further, the lower graph in FIG. 6 shows pixel values at each position on one line L1 in the visible light image of the banknote 90. In detail, the lower graph (curves Lr, Lg, Lb) in FIG. ) wavelength range component, green (G) wavelength range component, and blue (B) wavelength range component). In FIG. 6, the R wavelength range component is shown by a solid curve Lr, the G wavelength range component is shown by a broken curve Lg, and the B wavelength range component is shown by a dashed-dotted curve Lb. Note that, for the sake of simplification of illustration, etc., FIG. 6 and the like are shown with details etc. abstracted away.

As shown in the upper part of FIG. 6, the banknote 90 has a watermark area 91, a portrait clothing area 92, and a seal impression area 93. Each region 91, 92, 93 is arranged at a predetermined position within the banknote 90, respectively.

The watermark area 91 is an area where a watermark pattern is arranged, and is provided approximately at the center of the banknote 90. The watermark area 91 is a roughly white area in appearance, and is also referred to as a white area or a light-colored area. As shown in the lower part of FIG. 6, each component value (R, G, B) in the watermark area 91 is different from each component value (R, G, B) in another area (for example, portrait clothing area 92) in the banknote 90. , B).

The portrait clothing area 92 is provided on the right side of the watermark area 91. The portrait clothing area 92 is an area where clothing is depicted in a portrait of a predetermined person. The portrait clothing area 92 is a roughly blackish area (dark color) in appearance, and is also referred to as a black area or a dark color area.

The seal imprint area 93 is provided on the left side of the watermark area 91. The seal impression area 93 is an area in which the seal impression of a predetermined seal (for example, the seal of the Governor of the Bank of Japan) is drawn. The seal imprint area 93 is a roughly red area in appearance, and is also referred to as a red area.

In addition, fluorescent ink of a specific color is applied to the stamp area 93 to prevent forgery. When the imprint area 93 is irradiated with excitation light (UV light), the imprint area 93 emits red (or orange, etc.) light, for example. Here, it is assumed that within the banknote 90, fluorescent ink is applied only to the seal impression area 93. In other words, within the banknote 90, fluorescent ink is not originally applied to areas other than the seal impression area 93. However, the present invention is not limited thereto, and an area other than the stamp area 93 may exist within the banknote 90 as an area originally coated with fluorescent ink.

Note that the control unit 70 (determination unit 73, etc.) of the stain determination device 20 determines the positions of the watermark area 91, portrait clothing area 92, and seal imprint area 93 based on banknote specification data etc. stored in advance in the storage unit 60. It is possible to specify the The banknote specification data records the position, size, etc. of each area 91, 92, 93 for each banknote type (denomination). Based on the fluorescence image data (and/or visible light image data) and the banknote specification data regarding the banknote 90, the position of each area 91, 92, 93 within the banknote 90, etc. can be specified.

<Determination process regarding dirt>
Now, as mentioned above, in the technology (also referred to as the technology related to the comparative example) that uses the light reflected from paper sheets out of the light from a visible light source to determine the degree of dirt, it is possible to etc. is difficult to determine.

For example, when a visible light source is used as a light source, reflected light from completely new banknotes (official tickets, etc.) and banknotes that are slightly soiled due to body fluids such as saliva and/or hand grime (visually clean). The difference in intensity from the reflected light from the banknotes is small. Specifically, both the former banknotes (official tickets, etc.) and the latter banknotes (visually beautiful banknotes) have the same received light intensity distribution as in the lower part of FIG. (received light intensity). Therefore, with the technology according to the comparative example, it is difficult to accurately distinguish between the former banknotes and the latter banknotes based on the degree of dirt.

Here, even if a banknote looks clean, a banknote that is actually slightly soiled due to adhesion of body fluids such as saliva and/or hand grime will cause a greater fluorescence reaction than an official seal ticket. The inventor of the present application paid attention to such circumstances. This situation will be described in detail below with reference to FIGS. 7 to 10.

7 to 10 are diagrams showing information regarding fluorescence generated by irradiating the banknote 90 with excitation light. The lower images in each of FIGS. 7 to 10 are images of fluorescence generated in response to irradiation of the banknote 90 with excitation light (UV light). In addition, the graphs (curves Lr, Lg, Lb) in the upper row of each figure show the pixel values (received light intensity distribution) at each position within a certain main scanning line L1 on the banknote 90 in terms of wavelength range components (R wavelength range components). , G wavelength range component, and B wavelength range component). The R wavelength range component is shown by a solid curve Lr, the G wavelength range component is shown by a broken line Lg, and the B wavelength range component is shown by a dashed-dotted curve Lb. Note that, for the sake of simplification of illustration, these figures are also shown with details etc. abstracted away.

7 to 10 show the fluorescence reactions, etc. of banknotes 90 having different market distribution periods (in other words, degrees of contamination). FIG. 7 is a diagram showing the fluorescence reaction of a completely new banknote (official ticket, etc.) 90 (also referred to as 90A). FIG. 8 is a diagram showing the fluorescence reaction of a banknote 90 (also referred to as 90B) that has been distributed on the market for a certain period of time. The banknote 90B in FIG. 8 is slightly dirtier than the banknote 90A in FIG. FIG. 9 is a diagram showing the fluorescence reaction of a banknote 90 (also referred to as 90C) that has been distributed in the market for a longer period of time. The banknote 90C in FIG. 9 is dirtier than the banknote 90B in FIG. FIG. 10 is a diagram showing the fluorescence reaction of a banknote 90 (also referred to as 90D) that has been distributed in the market for a longer period of time. The banknote 90D in FIG. 10 is dirtier than the banknote 90C in FIG.

In this way, as the banknote 90A in FIG. 7 changes to the banknote 90D in FIG. 10, the degree of dirt gradually increases. However, even the banknote 90D (FIG. 10), which has the highest degree of dirt among them, looks sufficiently clean. Even when comparing the image of the banknote 90D in FIG. 10 taken with a visible light source and the image of a completely new banknote 90A (official ticket, etc.) taken with a visible light source, there is almost no difference between the two.

Here, as shown in FIGS. 7 to 10, as the degree of dirt gradually increases as the period of use of the banknote 90 in the market progresses, the intensity of fluorescence received from the banknote 90 gradually increases. go.

As shown in the lower part of FIG. 7, the banknote 90A in FIG. 7 has almost no fluorescence reaction (other than a part of the area 93), and the fluorescence image of the banknote 90A is a dark image as a whole. On the other hand, the fluorescence image of the banknote 90B in FIG. 8 is slightly brighter than the fluorescence image of the banknote 90A (FIG. 7). This is because a fluorescent reaction occurs in the banknote 90B, and the fluorescence due to the fluorescent reaction is detected. Furthermore, a larger fluorescent reaction occurs in the banknote 90C in FIG. 9, and an even larger fluorescent reaction occurs in the banknote 90D in FIG. Accordingly, the fluorescent image of the banknote 90D (FIG. 10) is acquired as an image brighter than each of the fluorescent images of the banknote 90A (FIG. 7), the banknote 90B (FIG. 8), and the banknote 90C (FIG. 9).

For example, the intensity of received fluorescence from the watermark area 91 and the portrait clothing area 92 gradually increases as the degree of dirt on the banknote 90 as a whole increases.

However, the stamp area 93, to which the fluorescent ink was originally applied, exhibits a different tendency of change than other areas. Specifically, in the seal imprint area 93, the fluorescent ink that was originally applied gradually wears out as the banknote 90 is marketed for a period of time. As a result, the intensity of the fluorescent light received from the seal imprint area 93 gradually decreases as the circulation period of the banknote 90 in the market passes.

In other words, the intensity of fluorescence received from an area within the banknote 90 to which fluorescent ink is not originally applied (also referred to as a "non-applied area of fluorescent ink") gradually increases. More specifically, the intensity of fluorescence received from areas other than the seal area 93 (for example, the watermark area 91 and/or the portrait clothing area 92, etc.) increases as the distribution period increases (and as a result, the amount of dirt increases). It gradually becomes larger.

Therefore, in consideration of such circumstances, in this embodiment, the determination process regarding stains is controlled based on the received intensity V1 of fluorescence from one fluorescent ink non-applied area C1 (for example, the watermark area 91) in the banknote 90. The process is executed by the unit 70 or the like.

Specifically, prior to the determination process, the banknote 90 is irradiated with excitation light (here, UV light) for generating fluorescence, and the fluorescence generated by the banknote 90 is received by the light receiving unit 55. Fluorescent image data regarding the banknote 90 is then generated (obtained) by the control unit 70 (step S1 (see FIG. 22)). Further, the control unit 70 calculates (obtains) the received intensity V1 of the fluorescence from the fluorescent ink non-applied area C1 (watermark area 91, etc.) in the banknote 90 based on the fluorescence image data (step S2). Then, the control unit 70 executes the determination process regarding dirt based on the received light intensity V1 (step S3). Further, the determination result in the determination process is output from the control section (identification control section) 70 to the main body control section 40 (step S4). Then, the main body control unit 40 executes classification processing based on the determination result. Specifically, the main body control section 40 discharges each banknote 90 to a discharge section (such as the reject section 12 and the stacker section 16) according to each determination result. Note that FIG. 22 is a flowchart showing the processing in the control unit 70 of the dirt determination device 20.

Here, the intensity V1 of the received fluorescence from the fluorescent ink non-applied area C1 in the banknote 90 is determined, for example, at a plurality of positions over the entire area of the watermark area 91 (the entire area having two-dimensional (area) expansion). It may be calculated as the average value (or maximum value) of the received fluorescence intensity at . However, the present invention is not limited to this, and for example, light is received as the average value (or maximum value) of the received fluorescence intensity at multiple positions within a part of the watermark area 91 (two-dimensional area or one-dimensional area). The intensity V1 may be calculated. Furthermore, the received intensity of the fluorescence at each position within the banknote 90 may be, for example, the received light intensity of only one wavelength range component (for example, the green wavelength range component) among the plurality of wavelength range components of the fluorescence. It is fine as long as it is used. However, the present invention is not limited to this, and for example, the average value of the received light intensity regarding the plurality of wavelength range components of the fluorescence (in other words, each pixel value of the grayscale image) is It may also be used as the received light intensity.

The control unit 70 (determination unit 73) uses the received intensity V1 of fluorescence from the watermark area 91 as an index value regarding dirt. For example, the determination unit 73 uses the value (itself) of the received light intensity V1 as an index value representing the degree of contamination. More specifically, the determining unit 73 determines that the higher the received light intensity V1 is, the higher the degree of dirt on the banknote 90 is. Here, the degree of dirt on the banknote 90 is further determined in a plurality of stages based on the received light intensity V1 (see FIG. 11). FIG. 11 is a diagram showing an example of classification regarding the degree of contamination.

For example, as shown in FIG. 11, when the received light intensity V1 is less than the threshold value TH1, it is determined that the degree of contamination is level E4 ("very clean" (no contamination at all)). Further, when the received light intensity V1 is greater than or equal to the threshold value TH1 and less than the threshold value TH2 (TH2>TH1), the degree of contamination is determined to be level E3 ("clean" (almost not soiled)). Further, when the received light intensity V1 is greater than or equal to the threshold value TH2 and less than the threshold value TH3 (TH3>TH2), the degree of contamination is determined to be level E2. Furthermore, when the received light intensity V1 is equal to or greater than the threshold value TH3, it is determined that the degree of contamination is level E1 ("considerably dirty" (a state in which unacceptable contamination exists)). The dirt on each banknote 90 is classified into one of a plurality of stages (four stages) from level E1, which has the highest degree of dirt, to level E4, which has the smallest degree of dirt. Note that level E2 indicates the degree of contamination between level E1 and level E3. Level E2 is, for example, a level indicating that it is "slightly dirty" (a state in which a certain degree of dirt exists). However, the present invention is not limited to this, and the level E2 may be a level indicating the meaning of "still clean" (not yet dirty).

Note that although the degree of dirt is classified here into four levels, the degree of dirt on each banknote 90 is not limited to this. ) may be classified into any of the following degrees.

According to the aspect described above, the stain determination device 20 determines whether the banknote 90 is stained based on the received fluorescence intensity V1 from the fluorescent ink non-applied area C1 (area to which no fluorescent ink is originally applied) within the banknote 90. Judgment is made regarding dirt on (paper sheets). Therefore, it is possible to realize highly accurate determination regarding dirt on banknotes 90. In particular, compared to conventional technology that uses light reflected from a visible light source on paper sheets to determine the degree of dirt, it is possible to realize highly accurate judgment regarding dirt on paper sheets (banknotes 90). It is.

In the embodiment described above, it is determined that the greater the received intensity V1 of fluorescence from the watermark area 91, the greater the degree of dirt on the banknote 90. That is, the dirt determining device 20 determines the dirt on the banknote 90 by determining the degree of dirt on the banknote 90. In other words, the process of determining the degree of contamination of the banknotes 90 is performed as an example of the process of determining the degree of contamination of the banknotes 90.

However, the present invention is not limited to this, and the process of determining whether or not paper sheets are soiled (the process of determining whether or not "paper sheets are soiled") may be executed as a determination process regarding soiling of banknotes 90. Good too. Specifically, the presence or absence of dirt (specifically, dirt larger than a predetermined level) may be determined based on the magnitude relationship between the received light intensity V1 and a predetermined threshold value. Specifically, when the received light intensity V1 is larger than a predetermined reference value, the banknote 90 is determined to be "dirty" (more dirty than a predetermined level), and the received light intensity V1 is determined to be more than the predetermined reference value. If it is smaller than , the banknote 90 may be determined to be "not dirty". For example, threshold value TH3 (or threshold value TH2) may be used as the predetermined reference value. In this way, the dirt determining device 20 may determine whether the banknote 90 is dirty by determining whether the banknote 90 is dirty.

Further, here, although the watermark area 91 is mainly illustrated as the fluorescent ink non-applied area C1, the present invention is not limited thereto. The fluorescent ink non-applied area C1 may be other areas, such as the facial skin area of the person on the banknote 90, the portrait clothing area 92 of the banknote 90, the peripheral area of the banknote 90, or the background area of the banknote 90, for example. Alternatively, the fluorescent ink non-applied area C1 may be a "patternless area" within a banknote or other paper sheet. Note that the fluorescent ink non-applied area C1 is preferably a light-colored area such as the watermark area 91 (or a patternless area). This is because light-colored areas such as the watermark area 91 are areas where fluorescence caused by dirt is more easily detected than dark-colored areas such as the portrait clothing area 92 (described later).

<2. Second embodiment>
In the first embodiment, the judgment process regarding dirt on the banknote 90 is performed based only on the received light intensity V1 in one fluorescent ink non-applied area C1 (for example, the watermark area 91) within the banknote 90. Not limited. For example, based on not only the received light intensity V1 in one fluorescent ink non-coated area C1 in the banknote 90, but also the received light intensity V2 in another fluorescent ink non-coated area C2 (a different area from the area C1) in the banknote 90. , a determination process regarding dirt on the banknote 90 may be performed. By performing normalization using the received light intensity V2, it is possible to realize a more accurate determination regarding dirt on the banknote 90. In the second embodiment, such an aspect will be described. As will be described later, the fluorescent ink non-applied area C2 is an area (such as the portrait clothing area 92) where stains are estimated to be less likely to be detected than the fluorescent ink non-applied area C1.

As the received light intensity V1, as in the first embodiment, for example, the average value (or maximum value) of the received light intensities at a plurality of positions within all or a part of the watermark area 91 may be used. Further, as the received light intensity V2, for example, the average value (or maximum value) of the received light intensities at a plurality of positions within all or part of the portrait clothing area 92 may be used.

Furthermore, as the received intensity of the fluorescent light at each position within the banknote 90, the received light intensity of only one wavelength range component (for example, the green wavelength range component) among the plurality of wavelength range components of the fluorescence is used. Bye.

For example, for each position of the fluorescent ink non-applied area C1 (watermark area 91), among the fluorescence from the fluorescent ink non-applied area C1 in response to excitation light irradiation, the received intensity of fluorescence in the green wavelength range is the received light intensity. It is sufficient if it is calculated as V1. Furthermore, regarding each position of the fluorescent ink non-applied area C2 (portrait clothing area 92), among the fluorescence from the fluorescent ink non-applied area C1 according to the irradiation with the excitation light, the received intensity of fluorescence in the same green wavelength range is It may be calculated as the received light intensity V2.

However, the present invention is not limited to this, and each position of the fluorescent ink non-applied area C2 has a wavelength range that is different from that of the fluorescent ink non-applied area C1 (for example, a blue wavelength area (, red wavelength area, or infrared wavelength area)). The received light intensity of fluorescence may be calculated as the received light intensity V2. Alternatively, the average value (in other words, each pixel value of a grayscale image) of the received light intensity of a plurality of wavelength range components of fluorescence at each position within the banknote 90 is the received light intensity of fluorescence at each position within the banknote 90. It may be used as

In the second embodiment, a determination regarding dirt on paper sheets is made based on the relative relationship (difference D2) between a plurality of received light intensities V1 and V2 in a plurality of regions. Therefore, compared to the case where dirt determination is made based on the absolute value of a single received light intensity V1, the influence of individual differences between each dirt determination device, the influence of light source deterioration, and the influence of temperature quenching phenomenon can be reduced. It is possible to suppress it.

Now, referring again to FIGS. 7 to 10. As described above, as the period of market circulation of the banknote 90 increases (as a result, the dirt on the entire banknote 90 increases), areas other than the stamp area 93 within the banknote 90 (watermark area 91, portrait clothing area 92, etc.) The fluorescence reaction gradually increases.

Further, as can be seen from FIGS. 7 to 10, the degree of increase in the fluorescence reaction (specifically, the degree of increase in the received fluorescence intensity) differs from region to region. As can be seen by comparing FIGS. 7 and 10, for example, the degree of increase in the received fluorescence intensity V1 from the watermark area 91 is greater than the increase in the received fluorescence intensity V2 from the portrait clothing area 92.

The portrait clothing area 92 appears to be a roughly black area (dark color) (black area or dark color area). The degree of increase in fluorescence reaction in such a black area (or dark color area) is smaller than the degree of increase in fluorescence reaction in a white area (or light color area) such as the watermark area 91. In other words, the portrait clothing area 92 is an area where dirt is difficult to be detected by fluorescence reaction. This is because part of the excitation light (UV light) irradiated to generate fluorescence is easily absorbed by the black area, and the amount of fluorescence generated is reduced in the portrait clothing area 92. It is assumed that In this way, it is estimated that the portrait clothing area 92 is an area where stains are less likely to be detected than the watermark area 91. In other words, the watermark area 91 and the portrait clothing area 92 differ in the ease with which stains are detected.

Due to such circumstances, as shown in FIGS. 7 to 10, the difference D2 between the received light intensity V1 and the received light intensity V2 increases with the increase in the market circulation period of the banknotes 90 (and the increase in dirt) gradually increases (see also FIG. 12). Note that FIG. 12 is a conceptual diagram showing, in a simplified manner, how the difference D2 increases as the dirt increases. The left side of FIG. 12 shows the received light intensity for the banknote 90A, and the right side of FIG. 12 shows the received light intensity for the banknote 90D.

Specifically, first, in the banknote 90A of FIG. 7 (see also the left side of FIG. 20), the difference D2 between the received light intensity V1 in the watermark area 91 and the received light intensity V2 in the portrait clothing area 92 is small. Thereafter, the difference gradually increases as the market distribution period increases. As a result, for example, in the banknote 90D of FIG. 10, the difference D2 between the received light intensity V1 and the received light intensity V2 is increased compared to the banknote 90A of FIG. 7 (see also the right side of FIG. 12). In this way, the difference D2 increases as the dirt on the banknote 90 increases.

Considering these circumstances, in this second embodiment, the received light intensity V1 in the fluorescent ink non-applied area C1 (watermark area 91) and the received light intensity V2 in the fluorescent ink non-applied area C2 (portrait clothing area 92) are adjusted. Let's focus on the difference D2. Then, based on the difference D2, determination processing regarding dirt on the banknote 90 (processing for determining the degree of dirt, etc.) is performed. Specifically, it is determined that the greater the difference D2, the greater the degree of dirt on the banknote 90.

Here, as the difference D2 between the received light intensity V1 and the received light intensity V2, the ratio α (=V1/V2) of the received light intensities V1 and V2 is first exemplified. The degree of soiling of the paper sheet is determined based on this ratio α. In other words, the ratio α is used as an index value representing the degree of contamination. Specifically, it is determined that the larger the ratio α, the greater the degree of dirt on the banknote 90.

Here, the degree of dirt on the banknote 90 is further determined in a plurality of stages based on the difference D2.

For example, when the ratio α is less than the threshold value H1, it is determined that the degree of dirt on the banknote 90 is level E4. Further, when the ratio α is greater than or equal to the threshold value H1 and less than the threshold value H2 (however, H2>H1), it is determined that the degree of dirt on the banknote 90 is level E3. Further, when the ratio α is greater than or equal to the threshold value H2 and less than the threshold value H3 (however, H3>H2), it is determined that the degree of dirt on the banknote 90 is level E2. Further, when the ratio α is equal to or greater than the threshold value H3, it is determined that the degree of dirt on the banknote 90 is level E1. Note that level E4 represents the lowest degree of contamination, and level E1 represents the highest degree of contamination.

However, the present invention is not limited to this, and a process of determining the presence or absence of stains on paper sheets based on the ratio α may be performed. Specifically, the presence or absence of dirt may be determined based on the magnitude relationship between the ratio α and a predetermined reference value. Specifically, if the ratio α is larger than a predetermined reference value (for example, threshold H3 or threshold H2), the banknote 90 is determined to be “dirty” (stained to a predetermined degree or more), and the ratio α is If it is smaller than the predetermined reference value, the banknote 90 may be determined to be "not soiled".

According to the aspect described above, similarly to the first embodiment, the determination process regarding dirt on the banknote 90 (paper sheet) is performed based on the received intensity V1 of fluorescence from the fluorescent ink non-applied area C1. Therefore, it is possible to realize highly accurate determination regarding dirt on banknotes 90.

Further, in particular, determination processing regarding dirt on the banknote 90 (paper sheet) is performed based not only on the received light intensity V1 but also on the received light intensity V2 of the fluorescence from the fluorescent ink non-applied area C2. Specifically, a determination process regarding dirt on the banknote 90 (paper sheet) is performed based on the difference D2 (more specifically, the ratio α) between the received light intensity V1 and the received light intensity V2. The difference D2 between the received light intensities V1 and V2 is a comparison result between the received light intensity V1 and the received light intensity V2 as a reference (reference received light intensity), and is normalized compared to the received light intensity V1 itself. In other words, the received light intensity V1 is normalized using the received light intensity V2. The fluorescent ink non-applied area C2 is also expressed as a reference area for normalizing the received fluorescence intensity V1 from the fluorescent ink non-applied area C1.

According to such a determination process, it is possible to realize a more accurate determination regarding dirt on the banknote 90. More specifically, for example, it is possible to suppress the influence of individual differences in dirt determination devices. Further, it is possible to suppress the influence of deterioration of the light source. Furthermore, it is possible to suppress the influence of temperature quenching phenomenon of fluorescence. These advantages will be explained in detail below.

First, the content of the determination made by the standard stain determination device will be explained. For example, assume that the received light intensity V2 is "5" and the received light intensity V1 is "10" for the banknote 90A in FIG. 7, and the received light intensity V2 is "10" and the received light intensity V1 is "10" for the banknote 90D in FIG. 30'' (see also FIG. 12). As described above, the received light intensity V1 is the received light intensity of fluorescence from the watermark area 91 (for example, the received light intensity in the green wavelength range), and the received light intensity V2 is the received light intensity of the fluorescence from the portrait clothing area 92 (for example, the received light intensity in the green wavelength range). (received light intensity in the area).

If the threshold value TH3 is set to "28" in the first embodiment, the degree of contamination is determined to be level E1 based on the fact that the received light intensity V1 ("30") is greater than the threshold value TH3 ("28"). judged accurately.

However, the received light intensity (V1, V2, etc.) may vary due to individual differences in dirt determination devices. For example, there may be a stain determining device that detects a generally slightly lower received light intensity than a standard stain determining device. Or, conversely, there may be a dirt determination device that detects a slightly higher received light intensity overall than the reference device.

Similarly, when the light source deteriorates, the received light intensity also decreases as the emitted light intensity decreases. That is, the received light intensity may fluctuate due to deterioration of the light source.

Furthermore, the received light intensity may fluctuate due to the temperature quenching phenomenon of fluorescence. The temperature quenching phenomenon of fluorescence is a phenomenon in which the received light intensity V decreases (the amount of fluorescence emitted decreases) as the temperature of a fluorescent substance (fluorescent ink, etc.) increases. Note that, conversely, when the temperature of the fluorescent substance (fluorescent ink, etc.) decreases, the received light intensity V increases. In this way, the received light intensity V can change as the temperature of the fluorescent material changes.

If the determination is made based only on the received light intensity V1 of one area C1 as in the first embodiment, there is a possibility that the determination may be influenced by individual differences among the dirt determination devices. In that case, it is relatively difficult to set an appropriate threshold value, and an erroneous determination regarding dirt may occur.

For example, due to the influence of individual differences in dirt determination devices, for the banknote 90D in FIG. 10 (see also the right side of FIG. 12), the received light intensity V2 decreases to "9" and the received light intensity V1 decreases to "27". Assume a degraded situation (see also the right side of Figure 13).

In this situation, the received light intensity V1 ("27") is smaller than the threshold value TH3 ("28"). Therefore, the degree of contamination is not accurately determined to be level E1, but may be erroneously determined to be level E2 (or E3, etc.). That is, an erroneous determination may occur due to the influence of individual differences among each dirt determination device. Furthermore, in this case, in the determination process according to the first embodiment, it is difficult to distinguish which of the following two types of devices caused the received light intensity V1 ("27"). Specifically, it is distinguished whether the results are detected by a standard device or by a device with a detection level different from the standard device (a device with significant individual differences from the standard device). It is difficult to do so.

On the other hand, in the second embodiment, the difference D2 between the received light intensity V1 and the received light intensity V2 is taken into consideration. Specifically, the ratio α between the received light intensity V1 and the received light intensity V2 is taken into consideration.

For example, when fluorescence detection is performed using a standard device (not affected by temperature quenching phenomenon, etc.), the ratio α for the banknote 90A in FIG. 7 is "2" (=10/5), and the ratio α in FIG. The ratio α for the banknote 90D is “3” (=30/10) (see also FIG. 12).

On the other hand, when fluorescence detection is performed using a non-standard device (when a temperature quenching phenomenon, etc. occurs), both the received light intensity V1 in the fluorescent ink non-applied area C1 and the received light intensity V2 in the fluorescent ink non-applied area C2 change. . Suppose that the received light intensity V1 and the received light intensity V2 decrease at the same rate due to individual differences in devices (or temperature quenching phenomenon), etc., and as described above, for the banknote 90D (FIG. 10), the received light intensity V1 becomes " 27'' and the received light intensity V2 becomes 9. At this time, the ratio α regarding the banknote 90D is "3" (=27/9). Even if there are individual differences between devices (even if a temperature quenching phenomenon occurs), the ratio α hardly changes. Similarly, the ratio α regarding the banknote 90A in FIG. 7 is "2" (=8/4), and the ratio α hardly changes. In this way, the ratio α functions as a normalized index value. Therefore, an appropriate threshold value THα can be set more easily than in the first embodiment. For example, the threshold value THα is set to an appropriate value between "2" and "3", for example "2.4". In this case, the banknote 90D in FIG. 10 is appropriately determined to be "dirty" based on the fact that the ratio α (= "3") is greater than or equal to the threshold value THα (= "2.4").

As described above, by using both the received light intensities V1 and V2 (specifically, the ratio α of the received light intensities V1 and V2), individual differences between devices can be The impact is reduced. Specifically, by using the ratio α, which is an index value normalized also using the received light intensity V2, the influence of individual differences between devices is reduced. Therefore, it is possible to more accurately perform the determination process regarding dirt. Further, a decrease in the received light intensity is similarly caused by deterioration of the light source and/or temperature quenching phenomenon. By using the ratio α of the received light intensities V1 and V2, the influence caused by these factors can be similarly reduced compared to the case where the determination is made only based on the received light intensity V1.

Further, in the embodiment described above, the difference D2 between the received light intensity V1 and the received light intensity V2 is determined as the ratio α between the received light intensity V1 and the received light intensity V2, but the difference is not limited thereto. The difference D2 between the received light intensity V1 and the received light intensity V2 may be determined as the difference ΔV2 (=V1-V2) between the received light intensity V1 and the received light intensity V2. Then, a process for determining the degree of staining of the paper sheet based on the difference ΔV2 may be executed. Specifically, it may be determined that the greater the difference ΔV2, the greater the degree of dirt on the banknote 90.

For example, when the difference ΔV2 is less than the threshold value TH21, it is determined that the degree of dirt on the banknote 90 is level E4. Further, when the difference ΔV2 is greater than or equal to the threshold value TH21 and less than the threshold value TH22 (TH22>TH21), it is determined that the degree of dirt on the banknote 90 is level E3. Further, when the difference ΔV2 is greater than or equal to the threshold value TH22 and less than the threshold value TH23 (TH23>TH22), it is determined that the degree of dirt on the banknote 90 is level E2. Furthermore, when the difference ΔV2 is equal to or greater than the threshold value TH23, the degree of dirt on the banknote 90 is determined to be level E1. Note that level E4 represents the lowest degree of contamination, and level E1 represents the highest degree of contamination.

Even in such a determination method, it is possible to suppress the influence of individual differences between each dirt determination device, the influence of deterioration of the light source, and the influence of temperature quenching phenomenon.

For example, assume two types of banknotes 90 (90D, 90F) having different degrees of dirt. One is a dirty banknote 90D, and the other is a banknote 90F that is less dirty than the banknote 90D. Furthermore, the received light intensities V1 and V2 for the banknote 90D are the detection results by the standard device, and the received light intensities V1 and V2 for the banknote 90F are detected by a device (generally higher than the standard device) that has a different detection level than the standard device. This is the detection result by a device that detects the intensity of received light. The received light intensities V1 and V2 for the banknote 90D are detection results in a state without the influence of temperature quenching phenomenon, etc., and the reception light intensities V1 and V2 for the banknote 90F are the detection results in a state with the influence of temperature quenching phenomenon etc. It is also expressed as

In such a situation, the received light intensity V1 acquired for the banknote 90D and the received light intensity V1 acquired for the banknote 90F may have the same value. However, in this case, the difference ΔV2 acquired for the banknote 90D is larger than the difference ΔV2 acquired for the banknote 90F. Further, the difference ΔV2 increases to reflect the actual degree of contamination. Specifically, the greater the actual degree of contamination, the greater the difference ΔV2. Therefore, it is possible to determine the actual degree of contamination more accurately than in the case where a determination regarding contamination is simply made based only on the received light intensity V1.

FIG. 13 is a conceptual diagram showing simplified detection results regarding these two banknotes 90F and 90D. The left side of FIG. 13 shows the received light intensity for the banknote 90F, and the right side of FIG. 13 shows the received light intensity for the banknote 90D.

As shown in FIG. 13, even if the received light intensity V1 of value "27" is detected for both banknotes 90D and 90F, the values of the received light intensity V2 for the two banknotes 90D and 90F are different from each other. . For example, the received light intensity V2 for the banknote 90D has a value of "9", and the received light intensity V2 for the banknote 90F has a value of "13". The difference ΔV2 regarding the banknote 90D is "18", and the difference ΔV2 regarding the banknote 90F is "14". In this way, the difference ΔV2 increases to reflect the actual degree of contamination. In this case, by setting the threshold value TH23 to an appropriate value (for example, "16"), it is possible to accurately determine the degree of dirt on the banknote 90D as the level E1. In this way, by using the difference ΔV2, which is an index value normalized also using the received light intensity V2, the influence of individual differences among devices, etc. is reduced.

Note that here, the degree of dirt on the banknote 90 is determined based on the difference ΔV2, but the present invention is not limited to this, and the presence or absence of dirt on the banknote 90 may be determined based on the difference ΔV2. In other words, if the difference D2 between the received light intensity V1 and the received light intensity V2 is larger than a predetermined value, it may be determined that the banknote 90 is dirty. Specifically, the presence or absence of dirt may be determined based on the magnitude relationship between the difference ΔV2 and a predetermined threshold value (for example, TH23 or TH22). Specifically, if the difference ΔV2 is larger than a predetermined reference value, the banknote 90 is determined to be "dirty" (soiled to a predetermined degree or more), and if the difference ΔV2 is larger than the predetermined reference value. If the difference is also small, the banknote 90 may be determined to be "not dirty". For example, the threshold value TH23 (or threshold value TH22) may be used as the predetermined reference value.

As described above, by using the received light intensities V1 and V2 (specifically, the difference ΔV2), the influence of temperature quenching phenomenon, the influence of light source deterioration, and/or Alternatively, the influence of individual differences among devices is reduced. Therefore, it is possible to perform the determination process regarding dirt more accurately.

<3. Third embodiment>
The third embodiment is a modification of the second embodiment. Below, differences from the second embodiment will be mainly explained.

In the second embodiment, the determination process regarding dirt on the banknote 90 is also performed based on the received light intensity V2 in the fluorescent ink non-applied area C2 (portrait clothing area 92) "inside the banknote 90". However, the present invention is not limited to this, and the determination process regarding dirt on the banknote 90 may also be performed based on the received light intensity V2 in the fluorescent ink non-applied area C2 "outside the banknote 90". In the third embodiment, such an aspect will be described. In the following, an area C23 (see FIG. 14) provided on a plate-shaped member (also referred to as a plate-shaped member) 59 in the line sensor unit 50 of the stain determination device 20 will be referred to as a fluorescent ink non-applied area C2 "outside the banknote 90". ) is exemplified.

14 and 15 are diagrams showing a line sensor unit 50 according to the third embodiment.

As shown in FIG. 14 and the like, a member 59 for the upper unit 50a and a member 59 for the lower unit 50b are provided. The member 59 for the upper unit 50a is provided at a position facing the condensing lens 53 of the upper unit 50a across the gap 39, specifically, on the upper surface of the lower unit 50b. Further, the member 59 for the lower unit 50b is provided at a position facing the condensing lens 53 of the lower unit 50b across the gap 39, specifically, on the lower surface of the upper unit 50a.

As shown in FIG. 15, the light receiving section 55 is arranged so as to have a length larger than the length (width) of the banknote 90 in a direction perpendicular to the conveyance direction of the banknote 90. The member 59 is provided near one end of the light receiving section 55 in the extending direction, at a position facing the condensing lens 53 and the light receiving section 55 outside of the portion through which the banknote 90 passes. The region C23 is provided on the surface of such a member 59 (see also FIG. 14). Note that FIG. 14 is a longitudinal cross-sectional view of the line sensor unit 50 cut at the position where the member 59 is present in the direction perpendicular to the conveyance direction of the banknotes 90.

Similarly to the light receiving section 55, the light emitting section 52 also has a length larger than the length (width) of the banknote 90 in the direction perpendicular to the conveyance direction of the banknote 90. Light (particularly excitation light (UV light)) from the light emitting unit 52 is irradiated not only to the banknote 90 but also to the area C23. Then, the light receiving unit 55 detects the received intensity V2 of the fluorescence generated in the region C23 in response to the irradiation of the excitation light from the light emitting unit 52.

The area C23 is an area where fluorescent ink is not originally applied and does not originally have a fluorescent reaction. The area C23 is formed, for example, as an area coated with non-fluorescent ink or a surface area of non-fluorescent resin, and is also referred to as a "non-fluorescent area." Note that the color of the region C23 is preferably black, but is not limited to this, and may be white or another color.

The region C23 is provided inside the line sensor unit 50, and human hand grime and the like are unlikely to adhere to the region C23. The area C23 is an area where the possibility of staining is lower than the fluorescent ink non-applied area C2 in the banknote 90. Therefore, the area C23 is an area in which the degree of change over time in the fluorescence reaction (the degree of change (increase) in the received fluorescence intensity over time) is smaller than the non-applied fluorescent ink area C1 (watermark area 91, etc.) in the banknote 90. be.

In this third embodiment as well, the same determination processing and the like as in the second embodiment are performed. However, this embodiment differs from the second embodiment in that the received intensity V2 of fluorescence generated in the region C23 in response to the irradiation of excitation light from the light emitting section 52 is used. With this aspect as well, it is possible to obtain the same effects as in the second embodiment.

Further, in the third embodiment, a determination process regarding stains on paper sheets (banknotes 90) is performed based on the received intensity V2 of fluorescence from a region C23 provided in the member 59 in the stain determination device 20. There is. Therefore, it is possible to realize even more accurate determination regarding dirt on paper sheets.

More specifically, as described above, the area C23 outside the banknote 90 and inside the stain determination device 20 is an area where the possibility of staining is lower than the fluorescent ink non-applied area C2 inside the banknote 90. In particular, the area C23 is an area that has almost no chance of being touched by human hands, unlike the area within the banknote 90. Therefore, the fluorescence reaction in region C23 hardly increases and remains constant. Therefore, the received light intensity V2 of the fluorescence from the region C23 functions very well as a reference for normalizing the received light intensity. In other words, the region C23 functions very well as a reference region (specifically, a non-fluorescent reference region) regarding the received fluorescence intensity. Since the intensity V2 of the received fluorescence from the area C23 is also used to determine the stains on the paper sheets, it is possible to achieve a more accurate determination regarding the stains on the sheets.

Further, in order to suppress the influence of temperature quenching reduction, it is preferable that the temperature of the member 59 and the temperature of the banknote 90 be controlled to be approximately the same. For example, by leaving both banknotes 90 to be processed and the paper sheet processing apparatus 10 in the same room for a certain period of time before processing, a situation where the member 59 and the banknote 90 have approximately the same temperature is created. should be formed.

Note that in the above embodiment, the region C23 is provided at a position facing the light receiving section 55, but the present invention is not limited thereto. For example, the region C23 may be provided at another position within the reading range of the light receiving sensor (the range in which the light receiving section 55 can receive fluorescence from the region C23). More specifically, the region C23 may be provided at a position slightly shifted downstream or upstream in the conveyance direction from the above-mentioned position (FIG. 14, FIG. 15, etc.).

<4. Fourth embodiment>
The fourth embodiment and the fifth embodiment are modifications of the second embodiment and the third embodiment. In the following, differences from the second embodiment and the like will be mainly described.

In the second and third embodiments described above, the determination regarding dirt is made based on the received fluorescence intensity V1 from the fluorescent ink non-applied area C1 and the received fluorescent light intensity V2 from the fluorescent ink non-applied area C2. It is being done.

On the other hand, in the fourth embodiment and the fifth embodiment, based on the received fluorescence intensity V1 from the fluorescent ink non-applied area C1 and the received fluorescence intensity V3 from the "fluorescence reaction reference area C3" (described below). Now, the manner in which the determination regarding dirt is made will be explained.

Here, the "fluorescence reaction reference area C3" is originally a reference area that exhibits a certain degree of fluorescence reaction. In the fourth embodiment, a fluorescence reaction reference region C3 (a region different from the region C1) inside the banknote 90 is illustrated, and in the fifth embodiment, a fluorescence reaction reference region C3 outside the banknote 90 is illustrated.

In the fourth embodiment, a seal imprint area 93 is illustrated as the fluorescence reaction reference area C3.

As described above, the imprint area 93 is an area where fluorescent ink (for example, red fluorescent ink) was originally applied, and is originally a reference area that exhibits a certain level of fluorescent reaction. For example, a fluorescence reaction larger than a predetermined level is detected in the seal imprint area 93 in the banknote 90A in FIG. 7 . In FIG. 7, it is shown that the received fluorescence intensity V3 from the stamp area 93 in the banknote 90A is higher (by a predetermined degree or more) than the received fluorescence intensity V1 from the watermark area 91 in the banknote 90A. There is. In particular, it has been shown that the red wavelength range component of the fluorescence from the seal imprint area 93 is much larger than the red wavelength range component (and green wavelength range component, etc.) of the fluorescence from other areas (watermark area 91 etc.). ing.

Further, in the stamp area 93, the fluorescent ink that was originally applied gradually wears out as the banknote 90 is distributed on the market. As a result, the intensity V3 of the fluorescence received from the stamp area 93 (particularly the red wavelength component) gradually decreases as the circulation period of the banknote 90 in the market passes (see FIGS. 7 to 10). .

On the other hand, as described above, in the fluorescent ink non-applied area C1 such as the watermark area 91, the degree of contamination tends to gradually increase due to the adhesion of human hand marks etc. as the market circulation period of the banknote 90 progresses. exist.

That is, as the market circulation period of the banknote 90 passes, the received fluorescence intensity V1 from the fluorescent ink non-applied area C1 gradually increases, and conversely, the received fluorescence intensity V3 from the fluorescence reaction reference area C3 increases. gradually decreases. Specifically, the received light intensity V1, which was smaller than the received light intensity V3, gradually increases, and the received light intensity V3, which was larger than the received light intensity V1, gradually decreases. As a result, the difference D3 between the received light intensity V1 and the received light intensity V3 gradually decreases as the market circulation period of the banknote 90 passes (see FIG. 16). FIG. 16 is a conceptual diagram showing how the difference D3 decreases as the market circulation period of the banknote 90 passes. The left side of FIG. 16 shows the received light intensity for the banknote 90A, and the right side of FIG. 16 shows the received light intensity for the banknote 90D.

Note that the received intensity V3 of the fluorescence from the fluorescence reaction reference area C3 (imprint area 93) may hardly change (reduce). However, even in this case, the difference D3 between the received light intensity V1 and the received light intensity V3 gradually decreases as the received light intensity V1 of the fluorescent light from the non-applied fluorescent ink area C1 increases.

Utilizing the above properties, the stain determination device 20 according to the fourth embodiment determines whether the banknote 90 is soiled based on the difference D3 between the received light intensity V1 and the received light intensity V3. Specifically, the stain determination device 20 determines the degree of stain on the banknote 90 based on the difference D3. Specifically, it is determined that the smaller the difference D3 is, the greater the degree of dirt on the banknote 90 is. More specifically, the degree of dirt on the banknote 90 is divided into a plurality of levels (for example, levels E1 to E4) based on the magnitude relationship between the difference D3 (more specifically, the value β or the value ΔV3) and one or more threshold values. will be determined.

However, the present invention is not limited to this, and the presence or absence of dirt on the banknote 90 (whether or not the banknote 90 is dirty) may be determined based on the difference D3. Specifically, if the difference D3 between the received light intensity V1 and the received light intensity V3 is smaller than a predetermined value, it may be determined that the banknote 90 is dirty.

Here, the difference D3 between the received light intensity V1 and the received light intensity V3 may be, for example, the difference ΔV3 between the received light intensity V1 and the received light intensity V3, or the ratio β between the received light intensity V1 and the received light intensity V3, etc. Good too. Specifically, the difference ΔV3 is the difference value obtained by subtracting the received light intensity V1 from the received light intensity V3 (ΔV3=V3-V1), and the ratio β is the value of the ratio of the received light intensity V3 to the received light intensity V1 (β=V3/ V1). In this way, for example, the value β or the value ΔV3 may be used as an index value representing the degree of contamination.

According to the aspect described above, similarly to the first to third embodiments, the determination regarding dirt on the banknote 90 (paper sheet) is made based on the received intensity V1 of the fluorescence from the fluorescent ink non-applied area C1. Processing is taking place. Therefore, it is possible to realize highly accurate determination regarding dirt on banknotes 90.

In particular, the determination process regarding dirt on the banknote 90 (paper sheet) is performed based not only on the received light intensity V1 but also on the received light intensity V3 of fluorescence from another area (fluorescence reaction reference area C3) within the same banknote 90. It is being done. Specifically, a determination process regarding dirt on the banknote 90 (paper sheet) is performed based on the difference D3 between the received light intensity V1 and the received light intensity V3. The difference D3 between the received light intensities V1 and V3 is a comparison result between the received light intensity V1 and the reference received light intensity V3 (reference received light intensity), and is normalized compared to the received light intensity V1 itself. In other words, the received light intensity V1 is normalized using the received light intensity V3. Further, the fluorescence reaction reference area C3 is a reference area for normalizing the received intensity V1 of the fluorescence from the fluorescent ink non-applied area C1.

Note that when the received light intensity V3 does not substantially change over time, the received light intensity V3 and the fluorescence reaction reference region C3 function particularly effectively as standards for normalization. Further, even if the received light intensity V3 decreases over time, the received light intensity V3 is determined from the fluorescence reaction reference area C3 in the banknote 90 that is the same as the detection area (fluorescent ink non-applied area C1) of the received light intensity V1. is the received intensity of fluorescence. Therefore, the received light intensity V3 and the fluorescence reaction reference area C3 effectively function as standards for normalization.

According to such a determination process, it is possible to realize a more accurate determination regarding dirt on the banknote 90 than in the case of determination using only the received light intensity V1. More specifically, for example, it is possible to suppress the influence of individual differences in dirt determination devices, and it is possible to suppress the influence of deterioration of the light source. It is also possible to suppress the influence of temperature quenching of fluorescence.

Furthermore, in this embodiment, as the degree of dirt on the entire banknote 90 increases, the received light intensity V3 gradually decreases and the received light intensity V1 gradually increases. Specifically, the received light intensity V3, which was higher than the received light intensity V1, gradually decreases, and the received light intensity V1, which was lower than the received light intensity V3, gradually increases. In this way, the received light intensity V1 and the received light intensity V3 change in opposite directions. In this case, the difference D3 between the received light intensity V1 and the received light intensity V3 generally changes more than the difference D2. Therefore, compared to the second embodiment, it is possible to grasp changes in dirt on the banknotes 90 with higher sensitivity.

Note that the received light intensity V3 is calculated, for example, as the average value (or maximum value) of the received light intensity at a plurality of positions over the entire area of the seal imprint area 93 (the entire area having a two-dimensional (area) spread). Bye. However, the invention is not limited to this, and for example, the received light intensity V3 is the average value (or maximum value) of the received light intensities at a plurality of positions in a part of the seal imprint area 93 (two-dimensional area or one-dimensional area). may be calculated.

In addition, the received intensity of fluorescence at each position within the banknote 90 may be, for example, one of the wavelength range components of the fluorescence (for example, the green wavelength range component or the red wavelength range component). ) is used.

More specifically, for the non-applied area C1 of fluorescent ink, the received intensity of fluorescence in the green wavelength range (see curve Lg in FIG. 7, etc.) is calculated as the received intensity V1, and for the fluorescence reaction reference area C3, the intensity of fluorescence in the red wavelength range is calculated as the received intensity V1. The received light intensity (see curve Lr in FIG. 7, etc.) is calculated as the received light intensity V2. In other words, the received intensity V1 of the fluorescence in a specific wavelength range of green among the fluorescence from the fluorescent ink non-applied area C1 in response to the irradiation with the excitation light, and the fluorescence from the fluorescence reaction reference region C3 in response to the irradiation with the excitation light. Of these, the received intensity V3 of fluorescence in a specific red wavelength range is used. In this way, it is preferable to find suitable fluorescence reception intensities in different specific wavelength ranges for each of the regions C1 and C3. According to this, since the received intensity of fluorescence in different wavelength ranges is detected in the fluorescent ink non-applied area C1 and the fluorescence reaction reference area C3, paper sheets are It is possible to realize even more accurate determination regarding types of dirt.

However, this is not limited to this, and for each region C1 and C3, the received light intensity of the same specific wavelength range of fluorescence (for example, both red specific wavelength ranges (or both green specific wavelength ranges)) is the received light intensity. It may be used as V1 and V3. In this case, a specific wavelength range component that decreases over time in the fluorescence reaction reference region C3 may be used. For example, in the fluorescence reaction reference region C3 (imprint region 93) to which red fluorescent ink was originally applied, the red wavelength range component decreases over time as described above. In this case, the received light intensity V3 of the fluorescence in the red wavelength range among the fluorescence from the region C3 and the received light intensity V1 of the fluorescence in the red wavelength range among the fluorescence from the region C1 may be used. Similarly, if green fluorescent ink was originally applied in the fluorescence reaction reference region C3, the received intensity V3 of the fluorescence in the green wavelength range among the fluorescence from the region C3 and the green fluorescence among the fluorescence from the region C1. The received fluorescence intensity V1 in the wavelength range may be used.

Alternatively, the average value of the received light intensity regarding a plurality of wavelength range components of the fluorescence (in other words, each pixel value of the grayscale image) may be used as the received fluorescence intensity at each position within the banknote 90. .

Further, in the embodiment described above, only the seal imprint area 93 exists as an area originally coated with fluorescent ink in the banknote 90, but the present invention is not limited to this. For example, as described above, an area other than the stamp area 93 may exist as an area originally coated with fluorescent ink. In that case, the other area may be used as the fluorescence reaction reference area C3, or the stamp area 93 may be used as the fluorescence reaction reference area C3.

<5. Fifth embodiment>
The fifth embodiment is a modification of the fourth embodiment. Below, differences from the fourth embodiment will be mainly explained.

In the fourth embodiment, the determination process regarding dirt on the banknote 90 is also performed based on the received light intensity V3 in the fluorescence reaction reference area C3 (specifically, the seal imprint area 93) "inside the banknote 90". However, the present invention is not limited to this, and the determination process regarding dirt on the banknote 90 may also be performed based on the received light intensity V3 in the fluorescence reaction reference region C3 "outside the banknote 90". In the fifth embodiment, such an aspect will be described. In the following, a fluorescent region C35 (see FIGS. 17 and 18) in the fluorescent screen 59B of the line sensor unit 50 will be exemplified as the fluorescent reaction reference region C3 "outside the banknote 90."

The fluorescent plate 59B is a plate-shaped member coated with a fluorescent substance, and is originally a member that exhibits a certain degree of fluorescent reaction. The fluorescent region C35 is a region provided on all or a part of the surface of the fluorescent screen 59B, and is originally a reference region that exhibits a certain degree of fluorescent reaction. That is, the fluorescent region C35 is one of the fluorescent reaction reference regions C3.

For example, the fluorescent region C35 is a region that emits fluorescence in a specific wavelength range (for example, red fluorescence, green fluorescence, blue fluorescence, etc.) in response to irradiation with excitation light. Note that it is preferable that the fluorescent region C35 be provided at a location where wear and tear can be avoided. Here, the fluorescent region C35 is provided on the surface of the fluorescent plate 59B, but the present invention is not limited to this, and the fluorescent region C35 is provided with fluorescent ink on the surface of a member other than the fluorescent plate 59B. It may also be an area where the

The fluorescent region C35 may be provided at the same position as the region C23 according to the third embodiment. However, in FIG. 18, the fluorescent region C35 is provided near the end on the opposite side from the region C23 (see FIG. 15) in the extending direction of the light receiving section 55. The fluorescent region C35 is not limited to this, and the fluorescent region C35 may be provided near the end on the same side as the region C23 in the extending direction of the light receiving section 55.

As shown in FIGS. 17 and 18, the light from the light emitting section 52 can be irradiated not only to the bill 90 but also to the fluorescent region C35. As shown in FIG. 18, the light receiving section 55 is arranged so as to have a length larger than the length (width) of the banknote 90 in a direction perpendicular to the conveyance direction of the banknote 90. The region C35 is arranged near one end of the light receiving section 55 in the extending direction so as to face the light receiving section 55, and is provided outside the portion through which the banknote 90 passes.

The region C35 is also irradiated with excitation light (UV light) in the same manner as the banknote 90, and the light receiving unit 55 detects the received intensity V3 of the fluorescence generated in the region C35.

In the fifth embodiment, the same determination process as in the fourth embodiment is performed using the received intensity V3 of fluorescence generated in the region C35 in response to the irradiation of excitation light from the light emitting unit 52. This also makes it possible to obtain the same effects as in the fourth embodiment.

In particular, in the fifth embodiment, determination processing regarding dirt on banknotes 90 (paper sheets) is performed based on the intensity of received fluorescence from fluorescent region C35 provided in member 59 in the dirt determination device. . Therefore, it is possible to realize even more accurate determination regarding dirt on paper sheets. More specifically, the fluorescent area C35 is an area that exists inside the stain determination device 20, and is an area where the possibility of occurrence of wear and tear is lower than that of the fluorescent reaction reference area C3 inside the banknote 90. Therefore, the received light intensity V3 of the fluorescence from the fluorescent region C35 functions very well as a reference for normalizing the received light intensity. In other words, the fluorescent region C35 functions very well as a reference region regarding the intensity of received fluorescence (specifically, a reference region that exhibits a certain degree of fluorescence reaction). Since the determination process regarding the dirt on the paper sheet is performed using also the intensity V3 of the received fluorescence from the fluorescent region C35, it is possible to realize a more accurate determination regarding the dirt on the paper sheet.

Furthermore, by using the received fluorescence intensity V3 from the fluorescent region C35 outside the banknote 90, even when the inside of the banknote 90 (inside the excitation light irradiation surface) is not coated with fluorescent ink, the banknote 90 becomes dirty. It is possible to realize highly accurate judgment regarding the above.

Note that in the above embodiment, the fluorescent region C35 is provided at a position facing the light receiving section 55, but the fluorescent region C35 is not limited thereto. For example, the fluorescent region C35 may be provided at another position within the reading range of the light receiving sensor (the range in which the light receiving section 55 can receive fluorescence from the fluorescent region C35). More specifically, the fluorescent region C35 may be provided at a position slightly shifted downstream or upstream in the transport direction from the above-mentioned position (FIG. 17, FIG. 18, etc.).

<6. Sixth embodiment>
In the first embodiment, the determination process regarding dirt on the banknote 90 is performed based on one index value regarding the received light intensity V1 of the fluorescent ink non-applied area C1 (watermark area 91, etc.), but this is not limited to this. Not done. A determination process regarding dirt on the banknote 90 may be performed based on two index values for each wavelength range (received light intensity for each wavelength range) regarding the received light intensity V1. For example, the determination process regarding dirt on the banknote 90 is performed based on the difference D6 between the received intensity V11 of fluorescence in a certain wavelength range regarding the non-applied fluorescent ink area C1 and the received intensity V12 of fluorescence in another wavelength range regarding the same area C1. may be performed. In the sixth embodiment, such an aspect will be described.

As shown in FIGS. 7 to 10, as the period of market circulation of banknotes 90 increases (as a result, the amount of dirt increases), the received light intensity V11 and the received light intensity V12 change with respect to the fluorescent ink non-applied area C1 (for example, the watermark area 91). The difference D6 gradually increases.

In the banknote 90A in FIG. 7, the difference D6 between the received intensity V11 of fluorescence in the green wavelength range in the watermark area 91 (see curve Lg) and the received intensity V12 of fluorescence in the red wavelength range in the watermark area 91 (see curve Lr) is small (see also Figure 19). FIG. 19 is a conceptual diagram schematically showing how the difference D6 increases as dirt increases. In FIG. 19, the received light intensities V11 and V12 of the fluorescence in two wavelength ranges among the fluorescence from the watermark area 91 are shown at different positions in the left-right direction for convenience of illustration. It is preferable that the two received light intensities V11 and V12 are actually received light intensities of fluorescence from the same position within the watermark area 91. However, the present invention is not limited thereto, and the two received light intensities V11 and V12 may be the received light intensities of fluorescence from different positions within the watermark area 91.

Thereafter, the difference D6 gradually increases as the market distribution period increases. As a result, for example, in the banknote 90D in FIG. 10, the difference D6 between the received light intensity V11 (see curve Lg) and the received light intensity V12 (see curve Lr) in the watermark area 91 is increased compared to the banknote 90A in FIG. (See also Figure 19). That is, the degree of increase in the received fluorescence intensity differs for each wavelength range component. Specifically, the degree of increase in the received intensity V11 of fluorescence in the green wavelength range in the watermark region 91 is greater than the degree of increase in the received intensity V12 of fluorescence in the red wavelength region in the watermark region 91.

Utilizing such properties, the stain determination device 20 according to the sixth embodiment determines that the degree of stain on the banknote 90 is greater as the difference D6 between the received light intensity V11 and the received light intensity V12 is larger. However, the present invention is not limited to this, and if the difference D6 between the received light intensity V11 and the received light intensity V12 is larger than a predetermined value, it may be determined that the banknote 90 is dirty.

Here, the difference D6 between the received light intensity V11 and the received light intensity V12 is, for example, the ratio γ between the received light intensity V11 and the received light intensity V12. The ratio γ is, for example, a value of the ratio of the received light intensity V11 to the received light intensity V12 (γ=V11/V12). Then, it is determined that the greater the ratio γ, the greater the degree of dirt on the banknote 90. More specifically, the degree of dirt on the banknote 90 is classified into a plurality of stages based on the magnitude relationship between the ratio γ and one or more threshold values. Alternatively, the presence or absence of dirt on the banknote 90 (whether or not the banknote 90 is dirty) may be determined based on the magnitude relationship between the ratio γ and a predetermined reference value.

Further, the difference D6 between the received light intensity V11 and the received light intensity V12 may be, for example, the difference ΔV6 between the received light intensity V11 and the received light intensity V12. The difference ΔV6 is, for example, a difference value obtained by subtracting the received light intensity V12 from the received light intensity V11 (ΔV6=V11−V12). Then, it is determined that the greater the difference ΔV6, the greater the degree of dirt on the banknote 90. Specifically, the degree of dirt on the banknote 90 is classified into a plurality of stages based on the magnitude relationship between the difference ΔV6 and one or more threshold values. Alternatively, the presence or absence of dirt on the banknote 90 may be determined based on the magnitude relationship between the difference ΔV6 and a predetermined reference value.

Note that the received light intensities V11 and V12 are calculated, for example, as the average value (or maximum value) of the received light intensities at a plurality of positions over the entire area of the watermark area 91 (the entire area having two-dimensional (area) expansion). It is fine if it is done. However, the invention is not limited to this, and for example, the received light intensity V1 is calculated as the average value (or maximum value) of the received light intensities at a plurality of positions in a part of the watermark area 91 (two-dimensional area or one-dimensional area). , V12 may be calculated.

As described above, in the sixth embodiment, similarly to the other embodiments, the determination process regarding stains on the banknote 90 (paper sheet) is performed based on the received intensity V1 of fluorescence from the fluorescent ink non-applied area C1. It is being said. Therefore, compared to the technology according to the above-mentioned comparative example, it is possible to realize a highly accurate determination regarding dirt on the banknote 90.

In particular, in the determination process of the sixth embodiment, the received light intensity V11 of light in one specific wavelength range among the fluorescence from the watermark area 91 and the light reception intensity of light in another wavelength range among the fluorescence from the watermark area 91 are determined. V12 is used. Specifically, the difference D6 between the received light intensity V11 and the received light intensity V12 is used. In other words, the received light intensity V11 is normalized using the received light intensity V12 (from the same bill 90 and the same area 91). According to this, it is possible to realize a more accurate determination regarding dirt on the banknote 90 than when determining using only a single received light intensity V11. Specifically, the influence caused by individual differences between devices can be reduced compared to the case where the determination is made only based on the received light intensity V11. Additionally, the effects of light source degradation and/or temperature quenching phenomena may be similarly reduced.

<7. Seventh embodiment>
The seventh embodiment is a modification of the sixth embodiment and the like. As described below, the idea of the sixth embodiment and the idea of the second embodiment (or third embodiment) may be combined.

In the determination process of the seventh embodiment, not only the received light intensities V11 and V12 regarding one fluorescent ink non-applied area C1 (watermark area 91 etc.) but also regarding another fluorescent ink unapplied area C1 (portrait clothing area 92 etc.) The received light intensities V21 and V22 (described later) are also taken into consideration. That is, in the seventh embodiment, similarly to the second and third embodiments, the received light intensity regarding the fluorescent ink non-applied area C2 (portrait clothing area 92, etc.) other than the fluorescent ink non-applied area C1 is also taken into consideration. Such an aspect will be explained below.

As shown in FIGS. 7 to 10, as the period of market circulation of banknotes 90 increases (as a result, the amount of dirt increases), the received light intensity V11 and the received light intensity V12 change with respect to the fluorescent ink non-applied area C1 (for example, the watermark area 91). The difference D71 gradually increases (see also FIG. 20). Note that FIG. 20 is a conceptual diagram schematically showing how the differences D71, D72 (described later), etc. change as the dirt increases.

First, in the banknote 90A in FIG. 7 (see also the left side of FIG. 20), the received intensity V11 of fluorescence in the green wavelength range in the watermark area 91 (see curve Lg) and the received intensity V12 of fluorescence in the red wavelength range in the watermark area 91 (See curve Lr) D71 is small. Thereafter, the difference gradually increases as the market distribution period increases. As a result, for example, in the banknote 90D in FIG. 10, the difference D71 between the received light intensity V11 (see curve Lg) and the received light intensity V12 (see curve Lr) is increased compared to the banknote 90A in FIG. (see also to the right).

Similarly, with an increase in the market circulation period of the banknotes 90 (as well as an increase in dirt), the difference between the received light intensity V21 and the received light intensity V22 also increases with respect to another fluorescent ink non-applied area C2 (for example, the portrait clothing area 92). D72 gradually increases (see also Figure 20). The received light intensity V21 is the received intensity of fluorescence in the green wavelength range in the portrait clothing region 92 (see curve Lg), and the received light intensity V22 is the received light intensity of fluorescence in the red wavelength range in the portrait clothing region 92 (see curve Lr). be.

In this way, as the dirt on the banknotes 90 increases, the difference D71 increases and the difference D72 also increases. In other words, the larger the received intensity of fluorescence from each region C1, C2 (for example, the average value of received light intensities for a plurality of wavelength ranges), the greater the received light intensity in the green wavelength range and the received light in the red wavelength range in each region C1, C2. The difference in strength becomes larger.

However, the degree of increase in the difference between the received light intensity in the green wavelength range and the received light intensity in the red wavelength range is different between the watermark area 91 and the portrait clothing area 92. Specifically, the degree of increase in the difference D71 between the two wavelength range components of the fluorescence from the watermark region 91 is greater than the degree of increase in the difference D72 between the two wavelength range components of the fluorescence from the portrait clothing region 92. Become. That is, the difference D71 regarding the watermark area 91 increases more than the difference D72 regarding the portrait clothing area 92. In other words, as the dirt on the banknote 90 increases, the difference D7 between the difference D71 and the difference D72 increases.

Utilizing such properties, the stain determination device 20 according to the seventh embodiment determines that the greater the difference D7 between the difference D71 and the difference D72, the greater the degree of stain on the banknote 90. However, the present invention is not limited to this, and if the difference D7 is larger than a predetermined value, it may be determined that the banknote 90 is dirty.

Here, for example, the difference D71 is the ratio γ71 between the received light intensity V11 and the received light intensity V12, and the difference D72 is the ratio γ72 between the received light intensity V21 and the received light intensity V22. More specifically, the ratio γ71 is the value of the ratio of the received light intensity V11 to the received light intensity V12 (γ71=V11/V12), and the ratio γ72 is the value of the ratio of the received light intensity V21 to the received light intensity V22 (γ72=V21 /V22). Further, the difference D7 is the ratio γ7 between the ratio γ71 and the ratio γ72, and more specifically, the value of the ratio of the ratio γ71 to the ratio γ72 (γ7=γ71/γ72).

Alternatively, the difference D71 may be the difference ΔV71 between the received light intensity V11 and the received light intensity V12, and the difference D72 may be the difference ΔV72 between the received light intensity V21 and the received light intensity V22. More specifically, the difference ΔV71 is the difference obtained by subtracting the received light intensity V12 from the received light intensity V11 (ΔV71=V11-V12), and the difference ΔV72 is the difference obtained by subtracting the received light intensity V22 from the received light intensity V21 (ΔV72=V21 -V22). Further, the difference D7 may be the difference ΔV7 between the difference ΔV71 and the difference ΔV72. More specifically, the difference ΔV7 may be a value obtained by subtracting the difference ΔV72 from the difference ΔV71 (ΔV7=ΔV71−ΔV72).

Note that the received light intensities V11 and V12 may be calculated in the same manner as in the sixth embodiment. The same applies to the received light intensities V21 and V22. For example, the received light intensities V21 and V22 are calculated as the average value (or maximum value) of the received light intensities at a plurality of positions over the entire portrait clothing area 92 (the entire area having two-dimensional (area) expansion). That's fine. However, the invention is not limited to this, and the received light intensity V21, V22 may be calculated.

As described above, in the seventh embodiment, similarly to the other embodiments, the determination process regarding dirt on the banknote 90 (paper sheet) is performed based on the received intensity V1 of fluorescence from the fluorescent ink non-applied area C1. It is being said. Therefore, compared to the technology according to the above-mentioned comparative example, it is possible to realize a highly accurate determination regarding dirt on the banknote 90.

In particular, in the determination process of the seventh embodiment, the received light intensities V11 and V12 of two types of light in specific wavelength ranges among the fluorescence from the watermark area 91 and two types of specific wavelengths of the fluorescence from the portrait clothing area 92 are determined. The received light intensities V21 and V22 of the light in the range are used. Specifically, the difference D7 between the difference D71 and the difference D72 is used. The difference D71 is a difference obtained by normalizing the received light intensity V11 using the received light intensity V12, and the difference D72 is the difference obtained by normalizing the received light intensity V21 using the received light intensity V22. The difference D7 is the difference obtained by normalizing the difference D71 by the difference D72.

According to such a determination process, it is possible to realize a more accurate determination regarding stains on the banknote 90 than when determining only based on a single received light intensity V1 (for example, V11) from the watermark area 91. . Further, it is possible to realize a more accurate determination regarding dirt on the banknote 90 than when determining only based on the single received light intensities V1 and V2 from the regions 91 and 92 (for example, only V11 and V21). . Specifically, the effects caused by individual differences in devices, the effects of light source deterioration, and/or the effects of temperature quenching phenomena can be reduced.

In the above embodiment, the intensity V2 of the fluorescence received from the portrait clothing area 92 is used as in the second embodiment, but instead of this, the intensity V2 of the fluorescence received from the area C23 is used as in the third embodiment. The received light intensity V2 may be used.

<8. Eighth embodiment>
The eighth embodiment is a modification of the sixth embodiment and the like. As described below, the idea of the sixth embodiment and the idea of the fourth embodiment (or the fifth embodiment) may be combined.

In the eighth embodiment, it is based not only on the received light intensities V11 and V12 regarding the fluorescent ink non-applied area C1 (watermark area 91) but also on the received light intensities V31 and V32 (described later) regarding the fluorescent reaction reference area C3 (imprint area 93). A determination regarding dirt on the banknote 90 is made. That is, in the eighth embodiment, similarly to the fourth and fifth embodiments, the received light intensity regarding the fluorescence reaction reference region C3 (seal impression region 93, etc.) is also taken into consideration. Such an aspect will be explained below.

Please refer to FIGS. 7 to 10 and 21. As the period of market circulation of banknotes 90 increases (as a result, the amount of dirt increases), the difference D81 gradually increases with respect to the fluorescent ink non-applied area C1 (watermark area 91). For example, the difference D81 is the difference between the received light intensity V11 (see curve Lg) and the received light intensity V12 (see curve Lr) in the watermark area 91. In other words, the difference D81 is the difference between the received intensity V11 of fluorescence in the green wavelength range in the watermark area 91 and the received intensity V12 of fluorescence in the red wavelength range in the watermark area 91. Note that FIG. 21 is a conceptual diagram schematically showing how the differences D81, D83 (described later), etc. change as the dirt increases.

On the other hand, regarding the fluorescence reaction reference area C3 (seal imprint area 93), the difference D83 gradually decreases as the period of market circulation of the banknote 90 increases (as a result, the amount of dirt increases) (see also FIG. 21). For example, the difference D83 is the difference between the received light intensity V31 (see curve Lg) and the received light intensity V32 (see curve Lr) in the seal imprint area 93. In other words, the difference D83 is the difference between the received intensity V31 of the fluorescent light in the green wavelength range in the stamp area 93 and the received intensity V32 of the fluorescent light in the red wavelength range in the stamp area 93.

Specifically, in the banknote 90A of FIG. 7, the difference D83 is much larger than the difference D81. Thereafter, as the market distribution period increases, the difference D83 gradually decreases and the difference D81 gradually increases. As a result, as also shown in FIG. 21, the difference D83 in the banknote 90D (FIG. 10) approaches the difference D81 in the banknote 90D.

In this way, as the dirt on the banknote 90 increases, the difference D83, which was larger than the difference D81, gradually decreases, and the difference D81, which was smaller than the difference D83, gradually increases. In other words, the difference D8 between the difference D81 and the difference D83 decreases.

Utilizing such properties, the dirt determination device 20 according to the eighth embodiment determines that the smaller the difference D8 between the difference D81 and the difference D83, the greater the degree of dirt on the banknote 90. However, the present invention is not limited to this, and if the difference D8 is smaller than a predetermined value, it may be determined that the banknote 90 is dirty.

Here, for example, the difference D81 is the ratio γ81 between the received light intensity V11 and the received light intensity V12, and the difference D83 is the ratio γ83 between the received light intensity V31 and the received light intensity V32. More specifically, the ratio γ81 is the value of the ratio of the received light intensity V11 to the received light intensity V12 (γ81=V11/V12), and the ratio γ83 is the value of the ratio of the received light intensity V31 to the received light intensity V32 (γ83=V31 /V32). Further, the difference D8 is the ratio γ8 between the ratio γ81 and the ratio γ83, and more specifically, the value of the ratio of the ratio γ83 to the ratio γ81 (γ8=γ83/γ81).

Alternatively, the difference D81 may be the difference ΔV81 between the received light intensity V11 and the received light intensity V12, and the difference D83 may be the difference ΔV83 between the received light intensity V31 and the received light intensity V32. More specifically, the difference ΔV81 is the value obtained by subtracting the received light intensity V12 from the received light intensity V11 (ΔV81=V11-V12), and the difference ΔV83 is the value obtained by subtracting the received light intensity V32 from the received light intensity V31 (ΔV83=V31 -V32). Further, the difference D8 may be the difference between the difference ΔV81 and the difference ΔV83. More specifically, the difference D8 may be the difference ΔV8 (ΔV8=ΔV83−ΔV81) obtained by subtracting the difference ΔV81 from the difference ΔV83.

Note that the received light intensities V11 and V12 may be calculated in the same manner as in the sixth embodiment. The same applies to the received light intensities V31 and V32. For example, the received light intensities V31 and V32 are calculated as the average value (or maximum value) of the received light intensities at a plurality of positions over the entire area of the seal imprint area 93 (the entire area having two-dimensional (area) expansion). Bye. However, the present invention is not limited to this, and for example, the received light intensity V3 , V32 may be calculated.

As described above, in the eighth embodiment, similarly to the other embodiments, the determination process regarding dirt on the banknote 90 (paper sheet) is performed based on the received intensity V1 of fluorescence from the fluorescent ink non-applied area C1. It is being said. Therefore, compared to the technology according to the above-mentioned comparative example, it is possible to realize a highly accurate determination regarding dirt on the banknote 90.

In particular, in the determination process of the eighth embodiment, the received light intensities V11 and V12 of two types of light in specific wavelength ranges among the fluorescence from the watermark area 91, and the received light intensities V11 and V12 of light in two types of specific wavelength ranges of the fluorescence from the seal imprint area 93 are determined. The received light intensities V31 and V32 of the light are used. Specifically, the difference D8 between the difference D81 and the difference D83 is used. The difference D81 is a difference obtained by normalizing the received light intensity V11 by the received light intensity V12, and the difference D83 is the difference obtained by normalizing the received light intensity V31 by using the received light intensity V32. The difference D8 is a difference obtained by further normalizing the difference D81 by the difference D83.

According to such a determination process, it is possible to realize a more accurate determination regarding stains on the banknote 90 than when determining only based on a single received light intensity V1 (for example, V11) from the watermark area 91. . Further, it is possible to realize a more accurate determination regarding dirt on the banknote 90 than when determining only based on the single received light intensities V1 and V3 from the regions 91 and 93 (for example, only V11 and V31). be. Specifically, the effects caused by individual differences in devices, the effects of light source deterioration, and/or the effects of temperature quenching phenomena can be reduced.

Further, as the period of market circulation of the banknotes 90 increases (eg, the degree of staining of the banknotes 90 as a whole increases), the difference D83 gradually decreases and the difference D81 gradually increases. Specifically, the difference D83, which was larger than the difference D81, gradually decreases, and the difference D81, which was smaller than the difference D83, gradually increases. In this way, the difference D81 and the difference D83 change in opposite directions. In this case, the difference D8 between the difference D81 and the difference D83 generally changes more than the difference D7. Therefore, compared to the seventh embodiment, it is possible to grasp changes in dirt on the banknotes 90 with higher sensitivity.

Note that in the above embodiment, the intensity V3 of the received fluorescence from the seal imprint area 93 is used as in the fourth embodiment. However, instead of this, similarly to the fifth embodiment, the received intensity V3 of the fluorescence from the fluorescent region C35 may be used.

<9. Others＞
Although the embodiments of the present invention have been described above, the present invention is not limited to the contents described above.

For example, the ideas of the above embodiments may be combined as appropriate. For example, the second embodiment and the fourth embodiment may be combined, and both the difference D2 and the difference D3 may be taken into consideration. More specifically, it may be determined that the object is "dirty" when the difference D2 is larger than a predetermined standard and the difference D3 is smaller than a predetermined standard. Note that, similarly, the third embodiment and the fifth embodiment may be combined, and the seventh embodiment and the eighth embodiment may be combined. According to the determination process based on a plurality of types of differences, it is possible to further improve the determination accuracy.

Further, in each of the above embodiments, dirt is determined based on either the "difference" or the "ratio", but the present invention is not limited to this, and the dirt is determined based on both the "difference" and the "ratio". may be determined. More specifically, when both the condition regarding the difference and the condition regarding the ratio are satisfied, it may be determined that the object is "dirty." Alternatively, it may be determined that the object is "dirty" when at least one of the condition regarding the difference and the condition regarding the ratio is satisfied.

Further, in each of the embodiments described above, the degree of dirt on the banknote 90 may be determined, and whether or not the banknote 90 is dirty may also be determined. For example, when it is determined that the degree of dirt on the banknote 90 is level E1, it is further determined that the banknote 90 is "dirty", and when it is determined that the degree of dirt on the banknote 90 is at levels E2 to E4, the banknote 90 is It may be further determined that it is "not dirty".

Furthermore, in each of the above embodiments, light from a white light source or a UV light source is irradiated, and a bandpass filter that selectively transmits light in different specific wavelength ranges is used to transmit light in each specific wavelength range to each light receiving element. Although light is being received, the present invention is not limited thereto.

For example, instead of a white light source, by providing multiple light sources for different wavelength ranges (multiple color light sources) and turning on the multiple light sources alternately, it is possible to generate visible light image data (image data for each wavelength range). Color image data, etc.)) can be obtained.

Specifically, the plurality of light sources may be caused to sequentially emit light in a time-sharing manner, and each light receiving element may sequentially receive light from the plurality of different light sources in a time-sharing manner. Specifically, four light sources, a blue light source, a green light source, a red light source, and an infrared light source, sequentially emit light in a time-sharing manner (at minute time intervals). Note that the blue light source is a light source that emits light in a wavelength range of approximately 400 nm to 500 nm, the green light source is a light source that emits light in a wavelength range of approximately 500 nm to 600 nm, and the red light source is a light source that emits light in a wavelength range of approximately 600 nm to 700 nm. It is a light source that emits light in the area. Further, the infrared light source is a light source that emits light in a wavelength range of approximately 700 nm to 1000 nm. More specifically, the four light sources sequentially emit light at a period (1/4 period) obtained by dividing one period of scanning time for each scanning line into four. Each light-receiving element without a band-pass filter sequentially receives light (reflected light from paper sheets) from a plurality of different light sources in a time-sharing manner. Each light receiving element receives light in the wavelength range of each color every 1/4 period, and detects the pixel value (received light intensity) of each color for each pixel in the scanning line. Visible light image data regarding the banknote 90 is acquired by repeating this operation for a plurality of scanning lines.

Alternatively, a plurality of light sources for each wavelength range (for example, a plurality of UV light sources that emit UV light in mutually different wavelength ranges) may be provided as the excitation light source. Then, the plurality of light sources may be made to emit light sequentially in a time-division manner, and each light receiving element may sequentially receive light from a plurality of different light sources in a time-division manner. Fluorescence image data (image data for each wavelength range (blue fluorescence image data, green fluorescence image data, red fluorescence image data, etc.)) can also be obtained by such alternating lighting operations of multiple light sources (excitation light sources). Is possible.

More specifically, the banknote 90 is sequentially irradiated with excitation light from a plurality of UV light sources (for example, two) having different wavelength ranges in a time-sharing manner. Specifically, the two light sources sequentially emit light at a period (1/2 period) obtained by dividing one period of scanning time for each scanning line into two. Each light-receiving element without a band-pass filter sequentially receives fluorescence generated from the banknote 90 in response to irradiation with excitation light from a plurality of different UV light sources in a time-sharing manner. Each light receiving element receives fluorescence in each wavelength range every 1/2 period, and detects the received light intensity (pixel value for each wavelength range) regarding two types of wavelength ranges for each pixel in the scanning line. Then, by repeating such an operation for a plurality of scanning lines, fluorescence image data (fluorescence image data regarding two types of wavelength ranges (for example, a green wavelength range and a red wavelength range)) of the banknote 90 is acquired.

Further, in each of the embodiments described above, two-dimensional image data regarding the paper sheet is acquired while the paper sheet is being conveyed, but the present invention is not limited to this. For example, two-dimensional image data regarding the paper sheet may be acquired by fixing the paper sheet at a predetermined position on a fixed base (for example, a desk). More specifically, a stationary paper sheet is irradiated with light from a visible light source, and the reflected light from the paper sheet is transmitted to a camera (a light-receiving section in which a large number of light-receiving elements are arranged in a two-dimensional manner). Visible light image data (two-dimensional image data) may be acquired by photographing with a photographing unit (having a photographing unit). Similarly, excitation light may be irradiated onto a fixed paper sheet, and fluorescence generated from the paper sheet may be photographed by the camera to obtain fluorescence image data (two-dimensional image data).

10 Paper sheet processing device 20 Paper sheet identification device (stain determination device)
50 Line sensor unit 51 Housing 52 Light emitting part 53 Condensing lens 54R, 54G, 54B, 54I Band pass filter 55 Light receiving part 56R, 56G, 56B, 56I Light receiving element 57 Substrate 58 Transparent part 59 Plate member 59B Fluorescent plate 90 Banknote 91 Watermark area 92 Portrait clothing area 93 Seal imprint area C1, C2 Fluorescent ink non-applied area C3 Fluorescent reaction reference area C23 Non-fluorescent area C35 Fluorescent area

Claims (28)

a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
A first area in the paper sheet to which fluorescent ink is not originally applied is identified as distinct from an area to which fluorescent ink is originally applied, and the fluorescent ink is generated from the first area. a control unit that determines whether the paper sheet is soiled based on a first received light intensity that is a received light intensity of fluorescence received by the light receiving unit;
A dirt determination device comprising: The stain determination device according to claim 1, wherein the control unit determines the stain on the paper sheet by determining the degree of stain on the paper sheet. 3. The soil determination device according to claim 1, wherein the control unit determines whether the paper sheet is soiled by determining whether or not the paper sheet is soiled. The stain determination device according to any one of claims 1 to 3, wherein the control unit determines that the greater the first received light intensity, the greater the degree of stain on the paper sheet. 5. The control unit determines that the paper sheet is dirty when the first received light intensity is greater than a predetermined reference value. Dirt determination device. The control unit is configured to detect fluorescence that is generated from a second area where it is estimated that dirt is less likely to be detected than the first area and is not originally coated with fluorescent ink and is received by the light receiving unit. The stain determination according to any one of claims 1 to 3, characterized in that dirt on the paper sheet is determined based on a second received light intensity that is a received light intensity and the first received light intensity. Device. The control section is configured to control a second received light intensity that is a received light intensity of fluorescence generated from a second region, which is a reference region that originally exhibits a certain level of fluorescence reaction, and is received by the light receiving section, and the first received light intensity. The stain determination device according to any one of claims 1 to 3, characterized in that the stain determination device makes a determination regarding stains on the paper sheet based on the following. 8. The stain determination device according to claim 6, wherein the second area is a different area from the first area within the paper sheet. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control unit is configured to detect fluorescence that is generated from a second area where it is estimated that dirt is less likely to be detected than the first area and is not originally coated with fluorescent ink and is received by the light receiving unit. Determining dirt on the paper sheet based on the second received light intensity, which is the received light intensity, and the first received light intensity,
A dirt determining device, wherein the second region is a predetermined region provided on a predetermined member within the dirt determining device. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control section is configured to control a second received light intensity that is a received light intensity of fluorescence generated from a second region, which is a reference region that originally exhibits a certain level of fluorescence reaction, and is received by the light receiving section, and the first received light intensity. Based on the above, determine the dirt on the paper sheet,
A dirt determining device, wherein the second region is a predetermined region provided on a predetermined member within the dirt determining device. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control unit is configured to detect fluorescence that is generated from a second area where it is estimated that dirt is less likely to be detected than the first area and is not originally coated with fluorescent ink and is received by the light receiving unit. A soil determination device, characterized in that soiling of the paper sheet is determined based on a difference between a second light reception intensity that is a light reception intensity of the first light reception intensity and the first light reception intensity. The stain determination device according to claim 11, wherein the control unit determines that the greater the difference between the first received light intensity and the second received light intensity, the greater the degree of stain on the paper sheet. 12. The control unit determines that the paper sheet is dirty when the difference between the first received light intensity and the second received light intensity is larger than a predetermined degree. Dirt determination device. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control section is configured to control a second received light intensity that is a received light intensity of fluorescence generated from a second region, which is a reference region that originally exhibits a certain level of fluorescence reaction, and is received by the light receiving section, and the first received light intensity. A stain determination device that determines whether the paper sheet is soiled based on the difference in the amount of dirt. The stain determination device according to claim 14, wherein the control unit determines that the smaller the difference between the first received light intensity and the second received light intensity, the greater the degree of stain on the paper sheet. 15. The control unit determines that the paper sheet is dirty if the difference between the first received light intensity and the second received light intensity is smaller than a predetermined value. Dirt determination device. Claims 11 to 12 are characterized in that the difference is a difference between the first received light intensity and the second received light intensity, or a ratio between the first received light intensity and the second received light intensity. 16. The dirt determination device according to any one of 16. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control unit is configured to control a first intensity that is a received intensity of light in a first wavelength range among the fluorescence from the first region, and a second wavelength different from the first wavelength range among the fluorescence from the first region. A dirt determination device, characterized in that dirt on the paper sheet is determined based on a difference from a second intensity that is a received light intensity of the area. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control unit is configured to detect fluorescence that is generated from a second area where it is estimated that dirt is less likely to be detected than the first area and is not originally coated with fluorescent ink and is received by the light receiving unit. Determining dirt on the paper sheet based on the second received light intensity, which is the received light intensity, and the first received light intensity,
The control unit includes:
A first intensity that is the received intensity of light in a first wavelength range among the fluorescence from the first region, and reception of light in a second wavelength range different from the first wavelength range among the fluorescence from the first region. a first difference that is a difference from a second strength that is the strength;
A third intensity is the received intensity of light in the first wavelength range among the fluorescence from the second region, and a fourth intensity is the received intensity of the light in the second wavelength range among the fluorescence from the second region. A soil determination device, characterized in that it determines whether the paper sheet is soiled based on a second difference, which is a difference between the two and the second difference. a light emitting unit that irradiates excitation light onto paper sheets to generate fluorescence in the paper sheets;
a light receiving unit that receives fluorescence generated from the paper sheet;
Based on the first received light intensity, which is the received light intensity of fluorescence generated from a first region within the paper sheet and to which fluorescent ink is not originally applied, and received by the light receiving section, the paper a control unit that makes a determination regarding soiling of leaves;
Equipped with
The control section is configured to control a second received light intensity that is a received light intensity of fluorescence generated from a second region, which is a reference region that originally exhibits a certain level of fluorescence reaction, and is received by the light receiving section, and the first received light intensity. Based on the above, determine the dirt on the paper sheet,
The control unit includes:
A first intensity that is the received intensity of light in a first wavelength range among the fluorescence from the first region, and reception of light in a second wavelength range different from the first wavelength range among the fluorescence from the first region. a first difference that is a difference from a second strength that is the strength;
A third intensity is the received intensity of light in the first wavelength range among the fluorescence from the second region, and a fourth intensity is the received intensity of the light in the second wavelength range among the fluorescence from the second region. A soil determination device, characterized in that it determines whether the paper sheet is soiled based on a second difference, which is a difference between the two and the second difference. A dirt determination device according to any one of claims 1 to 20,
A paper sheet processing device comprising: a) a step in which the computer identifies, in the paper sheet, a first area to which fluorescent ink is not originally applied, distinguishing it from an area to which fluorescent ink is originally applied;
b) a step in which the computer obtains a first received light intensity that is a received light intensity of fluorescence generated from the first region in response to irradiation of the excitation light to the paper sheet;
c) a step in which the computer determines whether the paper sheet is soiled based on the first received light intensity;
A dirt determination method comprising: a) A first value that is the received intensity of fluorescence generated from a first area within the paper sheet to which fluorescent ink is not originally applied in response to irradiation of the excitation light onto the paper sheet. the received light intensity; and the second received light intensity, which is the received light intensity of fluorescence generated from a second area where it is estimated that dirt is less likely to be detected than the first area and where no fluorescent ink is originally applied. a step in which the computer obtains the intensity;
b) a step in which the computer determines whether the paper sheet is soiled based on the difference between the first received light intensity and the second received light intensity;
A dirt determination method comprising: a) A first value that is the received intensity of fluorescence generated from a first area within the paper sheet to which fluorescent ink is not originally applied in response to irradiation of the excitation light onto the paper sheet. a step in which the computer acquires the received light intensity and the second received light intensity that is the received light intensity of the fluorescence generated from the second region, which is originally a reference region that exhibits a certain degree of fluorescence reaction;
b) a step in which the computer determines whether the paper sheet is soiled based on the difference between the first received light intensity and the second received light intensity;
A dirt determination method comprising: a) A first value that is the received intensity of fluorescence generated from a first area within the paper sheet to which fluorescent ink is not originally applied in response to irradiation of the excitation light onto the paper sheet. a step in which the computer acquires the received light intensity;
b) a step in which the computer determines whether the paper sheet is soiled based on the first received light intensity;
Equipped with
Step b) is:
b-1) The computer determines that a first intensity that is a received intensity of light in a first wavelength range among the fluorescence from the first region is different from the first wavelength range among the fluorescence from the first region. determining whether the paper sheet is soiled based on a difference from a second intensity that is a received intensity of light in a second wavelength range;
A dirt determination method comprising: a) A first value that is the received intensity of fluorescence generated from a first area within the paper sheet to which fluorescent ink is not originally applied in response to irradiation of the excitation light onto the paper sheet. the received light intensity; and the second received light intensity, which is the received light intensity of fluorescence generated from a second area where it is estimated that dirt is less likely to be detected than the first area and where no fluorescent ink is originally applied. a step in which the computer obtains the intensity;
b) a step in which the computer determines whether the paper sheet is soiled based on the first received light intensity and the second received light intensity;
Equipped with
Said step b) includes:
b-1) A first intensity that is the received intensity of light in a first wavelength range among the fluorescence from the first region, and a second wavelength range different from the first wavelength range among the fluorescence from the first region. a first difference that is a difference from a second intensity that is the received light intensity of the light;
A third intensity is the received intensity of light in the first wavelength range among the fluorescence from the second region, and a fourth intensity is the received intensity of the light in the second wavelength range among the fluorescence from the second region. a step in which the computer determines whether the paper sheet is soiled based on a second difference, which is a difference between the paper sheet and the paper sheet;
A dirt determination method comprising: a) A first value that is the received intensity of fluorescence generated from a first area within the paper sheet to which fluorescent ink is not originally applied in response to irradiation of the excitation light onto the paper sheet. a step in which the computer acquires the received light intensity and the second received light intensity that is the received light intensity of the fluorescence generated from the second region, which is originally a reference region that exhibits a certain degree of fluorescence reaction;
b) a step in which the computer determines whether the paper sheet is soiled based on the first received light intensity and the second received light intensity;
Equipped with
Said step b) includes:
b-1) A first intensity that is the received intensity of light in a first wavelength range among the fluorescence from the first region, and a second wavelength range different from the first wavelength range among the fluorescence from the first region. a first difference that is a difference from a second intensity that is the received light intensity of the light;
A third intensity is the received intensity of light in the first wavelength range among the fluorescence from the second region, and a fourth intensity is the received intensity of the light in the second wavelength range among the fluorescence from the second region. a step in which the computer determines whether the paper sheet is soiled based on a second difference, which is a difference between the paper sheet and the paper sheet;
A dirt determination method comprising: A program for causing the computer to execute the stain determination method according to any one of claims 22 to 27.

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