JP2001169056A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily acquire an infrared image of archaeological materials by using an inexpensive device without deteriorating the materials, and without forcing hardships to the operator. SOLUTION: A flatbed type image scanner uses an infrared pass filter 51, takes in only infrared rays from an object 9 in a CCD sensor 49 and reads the infrared image of the object 9. The scanner is provided with a visible light pass filter 53 in addition to the filter 51 and can read both an infrared image and a visible light image by selectively using the both filters. A battery can be used a power supply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for optically reading an image, and more particularly to a device called an image scanner or a document scanner (hereinafter, generally referred to as an image scanner).

[0002]

2. Description of the Related Art An image scanner irradiates light from a light source onto a small area of an object (typically a sheet-like object such as paper, but sometimes a three-dimensional object). While scanning the target object with the irradiation light, reflected light or transmitted light from each part of the object is received by a photoelectric conversion element such as a CCD line sensor, converted into an electric signal, and output. , Data of the entire image of the object is constructed. In many cases, image data output from an image scanner is captured by a device having an image processing function such as a computer, and is displayed on a screen or printed out.

Conventionally, when a read image is displayed or printed on a computer screen, the displayed or printed image has the same natural color tone as when an object is viewed with the naked eye. It is considered an important performance of the image scanner. In order to enhance this performance, many improvements have conventionally been made on the sensitivity characteristic in the visible light region. On the other hand, light existing outside the visible light range, such as infrared light, causes a read image to be unnatural. Therefore, a lamp that emits substantially only visible light, such as a mercury fluorescent lamp, is used as a light source.

As described above, the conventional image scanner is
It has been developed and used exclusively for the purpose of creating an image similar to the image seen by the naked eye as data.

[0005]

By the way, in the field of cameras, special-purpose cameras such as infrared cameras and ultraviolet cameras are known. For example, infrared cameras have been used to study archeological materials. In other words, characters and patterns are often drawn on pottery, wooden letters, ancient documents, and the like using ink. However, many materials have been hard to read with the naked eye as to what was described there due to weathering, contamination, discoloration, deterioration, etc. over many years. When such a material is photographed with an infrared camera, the characters and patterns emerge much more clearly than when viewed with the naked eye, making them easier to read. The reason is that black (carbon) used to draw letters and patterns has a significantly higher infrared absorption (ie, lower infrared reflectance and transmittance) than other materials. . Paper, wood, ceramics, etc., which are the base materials of the material, have high infrared reflectance, and dirt (mainly dust and metal) and other dyes attached to the surface of the material have high infrared transmittance. Therefore, in infrared photography, only the characters and patterns drawn with sumi stand out in black.

[0006] Despite these advantages, however, infrared cameras have not been actively utilized in archeological research. One of the reasons is that the price of the camera is very high (about 2 to 3 million yen), which is combined with the equipment such as an infrared projector or video printer and the equipment necessary for processing the resulting data. The price of the entire set will be very high (eg 1500
About 10,000 yen). Further, a more essential and serious problem is that extremely valuable and delicate archeological materials can be degraded and ruined by the large amount of infrared radiation. That is, when an image is taken by an infrared camera, a light source that emits a large amount of infrared rays (radiant heat rays) called an infrared projector is used because the amount of infrared rays is insufficient with a normal light source. In addition, for a thorough study, it is necessary to photograph one material from various angles and to take a number of photographs from the same angle, so that the photographing time is considerably long. Thus, the material will continue to be exposed to a large amount of infrared radiation over a long period of time, so that the temperature will increase, the water will evaporate and dry, and the condition will only worsen.

[0007] In addition, since the infrared camera needs to be provided with an infrared projector or the like, there is a problem that it cannot be easily and quickly performed anytime and anywhere (for example, at an excavation site). In addition, for photographers,
Since it is necessary to continue shooting while enduring the heat caused by the large amount of heat generated by the infrared projector (usually two units need to be used), there is a problem that shooting is particularly difficult in summer. In addition, it is difficult to uniformly illuminate the material with the infrared projector because of its structure.Since infrared rays cannot be seen with the naked eye, the arrangement and direction of the projector and the material to optimize the lighting conditions such as exposure and illuminance are difficult. In other words, it is difficult to be exposed to external light such as sunlight and indoor lighting, and the lighting conditions differ depending on the shooting location and opportunity.In other words, always shoot materials under the same, uniform and optimal lighting conditions It is difficult. Furthermore, since the infrared projector generates a large amount of heat, it is important to turn off the power of the infrared projector after shooting is completed.However, there is a risk that the infrared projector will be forgotten to be turned off because infrared rays cannot be seen. The photographer must be very careful about the danger.

Accordingly, an object of the present invention is to provide an infrared image of archeological material by using an inexpensive device without deteriorating the material, easily and without giving the actor a pain. Is to do.

Another object of the present invention is to make it possible to easily obtain images of different light types such as a visible light image and an infrared image of the same material using one inexpensive device. is there.

[0010]

SUMMARY OF THE INVENTION According to the present invention, an image scanner which has been conventionally used exclusively for acquiring a visible light image is utilized for acquiring an image of light other than visible light such as an infrared image. Was invented by a very novel idea that no one had ever conceived.

That is, an image reading apparatus according to a first aspect of the present invention is an image scanner configured to read an infrared image of an object.

More specifically, the image reading apparatus according to the first aspect of the present invention comprises a light source for generating light including infrared rays and the light source limited to a small area of a part of the entire area of the object. From the limited area irradiating means for irradiating the light from the scanning means to move the small area irradiated with the light so as to scan the entire area, from a predetermined position in the small area irradiated with the light Optical imaging means for receiving reflected or transmitted light to form an optical image at each predetermined position in the small area; and at each time during scanning, a predetermined area in the small area formed by the optical imaging means. A photoelectric conversion unit having sensitivity to infrared rays for receiving an optical image at each position and converting the optical image into an electric signal, and the light source receives the object from the light source so that light received by the photoelectric conversion element is substantially limited to infrared rays. The light through an object Comprising a filter means for performing filtering light reaching the transducer, and output means for receiving the electrical signal from the photoelectric conversion means to generate the image data of the object output.

The image reading apparatus according to the present invention irradiates infrared rays only to a small area of a part of the whole area of the object, and moves the small area of the infrared irradiation to move the entire area of the object. While scanning, at each point during the scan, reflected light or transmitted light from a small area is photoelectrically converted into image data. Therefore, the irradiation time of the infrared rays received by each part of the object in the image reading process is extremely short (for example, about 1 to 2 seconds). That is, individual portions of the object receive only the minimum amount of infrared light required to image the portion. Therefore, the amount of infrared radiation received by the object is extremely small, incomparable with the infrared camera, and there is virtually no problem of temperature rise and drying of the object, thus damaging archeological materials Without that, the infrared image can be obtained. In addition, some archeological materials are written in black and dye, but the dye is in a state of transition (high entropy) due to aging, and when it is exposed to ultraviolet light,
Deterioration will be accelerated. The apparatus of the present invention can be configured so that the light applied to the material does not include ultraviolet light, and thus, the deterioration of the material due to the ultraviolet light can be prevented. In addition, wooden simplicity is in a state called "chips" (thin trees are used for character practice, etc.)
It may be excavated in large quantities, but since it is curled like shavings, it is difficult to extend it in a plane and shoot it with infrared camera shooting, and more and more with infrared irradiation Curling. On the other hand, in an apparatus using the image scanner (particularly a flatbed type) of the present invention, it is easy to extend the curling and read an image. In addition, in infrared camera photography, since the camera is mounted directly above the material, the material is always exposed to the danger of damage due to the camera or lens falling, which is the only valuable thing This is a very important issue for archeological materials. In contrast,
With the device according to the invention, the risk of material damage is very low. These advantages are completely new advantages that could not be expected or expected when the conventional image scanner was used only for acquiring visible light images.

In addition, in relation to the above points, the total amount of infrared rays emitted from the light source is so small as to be insignificant compared with the infrared projector, so that the amount of heat generated by the apparatus is quite small,
Therefore, the photographer does not feel extra heat as in the case of photographing with an infrared camera, and the image reading operation is extremely easy. This advantage was also unexpected in comparison between normal visible light camera photography and image scanner reading,
This is a completely special advantage.

The image reading apparatus of the present invention has a structure in which all of the above-described components are housed in one casing, similarly to a conventional image scanner for visible light, and its size, weight, and manufacturing cost Is not much different from the conventional image scanner for visible light. Therefore, compared to an infrared camera, it is very inexpensive, easy to carry, does not require troublesome preparation work such as installation of an infrared projector, and anytime and anywhere (for example, excavation) It is possible to easily read an image of an object (even in a place such as a site).

Further, in archeology, researchers draw various drawings such as a sketch of an excavation site, a layout drawing of excavated relics, and sketches. Normally, such drawings are drawn on grid paper in order to improve the accuracy. However, when the drawings are later converted into digital data, the grid of the paper becomes an obstacle, and the drawing is often traced again. With the image reading device of the present invention, since the grid printed with the dye transmits infrared light, only a drawing drawn with a pencil containing carbon having a high infrared absorption rate is taken out, so that re-tracing is no longer necessary. is there. This advantage can be used not only in archeology but also in various other paper processing fields.

In addition, since the image captured by the infrared camera is an image of the object viewed from one point of the pupil of the camera, the shape and size of the object cannot be faithfully represented. Low. On the other hand, the image reading device of the present invention receives light from all parts of the object at the same angle and converts the light into image data, so that the geometric accuracy of the shape and size of the object is extremely high. You can get the image. This is also very advantageous for studying archeological materials. Further, the image reading apparatus of the present invention can uniformly illuminate the material, and can read at any time and under the same light amount and light quality conditions without being affected by external light. The reliability of the quality is high and its value as research material is high. In fact, archeological photographs taken with infrared cameras are often unusable as research materials due to uneven lighting and low geometric accuracy. On the other hand, the image data read by the apparatus of the present invention has a sufficient quality as a research material, and therefore has a great contribution to the development of archeology.

In a preferred embodiment, a light source that emits both visible light and infrared light (for example, a xenon fluorescent lamp) is used as a light source, and a photoelectric conversion unit that is sensitive to both visible light and infrared light is used. As a filtering means, an infrared transmission filter for cutting off light other than infrared light and a visible light transmission filter for cutting off light other than visible light are provided. Any of the images can be read. It is possible to acquire both an infrared image and a visible light image of the same archeological material with the same device without preparing separate devices for infrared light and visible light. Moreover, since the filter can be switched with just one simple operation of switching the filter without moving the material set in the device at all, the infrared image and visible light image of the same archeological material can be easily viewed from exactly the same angle. Can be obtained.

Since both an infrared image and a visible light image of archeological materials from exactly the same angle can be easily output from the same device, the amount of analysis information that can be taken into a computer or the like increases, and the comparison and analysis of both can be performed accurately and immediately. Can contribute greatly to research. For example, among archeological materials, some characters and patterns are written in black ink, and some are written in dye-based paint, but if you take both infrared and visible light images and compare them, Characters appear in the infrared image, and the dye-based paint disappears.
It is easy to distinguish.

In addition, if the above-mentioned advantage that only drawings drawn with a carbon-containing material can be taken out on paper is utilized, even in the general office equipment field (office image scanners, copiers, facsimile machines, etc.), it is possible to read scanned originals. Depending on the combination of the selection of the writing instrument used for the description and the selection of the infrared image and the visible light image, a different image can be obtained depending on the application. For example, in the visible light reading mode, the original is read as seen, but in the infrared reading mode, only the description portion of pencil or black (in some cases, the original description below the portion overcoated with the correction liquid) is read. It is like.

When a light source that emits only infrared light is used, the infrared light cannot be seen by the naked eye, and it is difficult to determine whether or not the device is operating only by looking at the device. If you use one that emits both infrared rays,
Since visible light can be seen with the naked eye, it is obvious at a glance whether or not the camera is operating.

In a preferred embodiment, a scan image of an object is accurately formed on a light receiving surface of a photoelectric conversion element depending on whether an infrared pass filter or a visible light pass filter is used. The image forming apparatus further includes optical characteristic adjusting means for adjusting the image forming characteristics of the optical image forming means. That is, when a scan image of an object is formed on a light receiving surface of a photoelectric conversion element using a lens system, infrared light and visible light have different wavelengths (infrared light is 800 nm to 900 nm in the near infrared region). ,
Visible light is 450 nm, 530 nm, 6
10 nm), the imaging positions of the scan images differ by several mm,
As it is, it is not possible to match the image formation position of both lights with the light receiving surface of the photoelectric conversion element. Therefore, means for compensating for the difference between the image forming positions is provided. For example, as one simple and effective specific means, a method of increasing the thickness of a material such as a glass plate constituting (or holding) a visible light pass filter by a required amount than that of an infrared pass filter is adopted. I can do it. Alternatively, the arrangement of the lens system and the position of the photoelectric conversion element may be adjusted in accordance with whether infrared light or visible light is used, so that the image forming position matches the light receiving surface of the photoelectric conversion element.

The preferred embodiment may use a battery as a power source. By using a battery, the usability at an excavation site or the like is further improved. Alternatively, power may be supplied from an interface for data communication with a computer.

An image reading apparatus according to a second aspect of the present invention is an image scanner capable of acquiring both a visible light image and an infrared or ultraviolet image other than visible light with one apparatus.

More specifically, the image reading apparatus according to the second aspect of the present invention includes a light source that generates visible light, light including at least one of infrared light and ultraviolet light, and a light source that emits light including at least one of the entire area of the object. Limited area irradiating means for irradiating the light from the light source only to a small area of the part, scanning means for moving the small area irradiated with the light so as to scan the entire area, and the light is irradiated Optical imaging means for receiving light reflected or transmitted from each predetermined position in the small area to form an optical image at each predetermined position in the small area; and at each time during scanning, the optical imaging means Photoelectric conversion means having sensitivity to visible light, at least one of infrared light and ultraviolet light, for receiving an optical image at a predetermined position in the small area formed by the above and converting the optical image into an electric signal, and the photoelectric conversion element But The light emitted from the light source or the light emitted from the light source through the object to the photoelectric conversion element is selected so that the light emitted from the light source is substantially limited to one type of light selected from visible light, infrared light, and ultraviolet light. And an output unit that receives the electric signal from the photoelectric conversion unit, generates and outputs image data of the object.

According to this image reading device, the visible light image and the infrared or ultraviolet image of the same object viewed from the same angle can be read without damaging the object by using this one device. .

In a preferred embodiment, the light mode selecting means performs filtering such that only one selected type of light passes through a light beam from the light source to the photoelectric conversion element via the target object (for example, , A visible light pass filter, an infrared pass filter, an ultraviolet pass filter, etc. which can be switched. Instead of using such selection of the optical filter, a visible light lamp that emits visible light, an infrared lamp that emits infrared light, or an ultraviolet lamp that emits ultraviolet light is provided as a light source. The light mode selection may be performed by selectively lighting any one of them. In this case, if the selection of the lamp is switched at a high speed during the scanning, the reading of the visible light image and the reading of the infrared image or the ultraviolet image can be completed in one scan.

[0028]

FIG. 1 shows the appearance of an infrared image scanner according to an embodiment of the present invention.

The image scanner 1 is of a flat bed type, and has a platen 5 made of a transparent glass plate on the upper surface of a substantially cubic casing 3. A document table cover 7 for pressing a document placed on the document table 5 from above is hingedly connected to the casing 3 with a hinge.

FIG. 2 is a block diagram schematically showing components housed inside the casing 3.

A carriage 17 is provided in the casing 3 so as to be able to linearly reciprocate below the document table 5 in the longitudinal direction of the casing 3 (along the line AA 'in FIG. 1). That is, the carriage 17 is coupled to the transport belt 13 and can linearly reciprocate below the document table 5 along the guide rail 11 by the power of the motor 15. The carriage 17 is an elongated cylindrical body that extends over the entire width of the document table 5 in a direction perpendicular to the direction of movement of the carriage 17. Necessary optical components are accommodated.

In the casing 3, a control circuit 19,
Electric circuits such as an output circuit 21 and a power supply circuit 23 are housed therein. The control circuit 19 controls the motor 15 for moving the carriage 17 during image reading, controls optical components in the carriage 17 (for example, switching of a filter, control of operation of a lamp and a line sensor, and the like), and output. The control of the circuit 21 is performed. The output circuit 21 receives an electric signal output from a line sensor in the carriage 17 and digitizes the signal to create and output image data. The power supply circuit 23 receives power from the AC commercial source 25 or the battery 27 and supplies drive power to the motor 15, the carriage 17, the control circuit 19, the output circuit 21, and the like.

By using the battery 27 as a power source, it is possible to use the image scanner 1 even in a place where power cannot be obtained from the outside, and it is easy to read an image from a material at an archeological site such as an archeological site. Become.

A power button 2 is provided on the outer surface of the casing 3.
9, light mode changeover switch 31, magnification control button 3
3, a liquid crystal display 35, a computer interface connector 37, and the like. The power button 29 is the power circuit 23
To turn on / off the power supply. The light mode changeover switch 31 instructs the control circuit 19 to switch the light mode (infrared light mode and visible light mode). The control circuit 19 is provided in the carriage 17 in response to the operation of the switch 31. By switching the two types of optical filters (described later), an infrared mode for reading an infrared image and a visible light mode for reading a visible light image are switched. The magnification control button 33 is connected to the control circuit 1
9 is instructed to increase / decrease the magnification of image reading. The liquid crystal display 35 displays a message from the control circuit 19 indicating a reading magnification, an optical mode, and the like.
The computer interface connector 37 is connected to a computer (not shown) to pass control commands from the computer to the control circuit 19 and to send image data from the output circuit 21 to the computer 37 (for example, a SCSI interface connector). It is. Even without using the switch 31 or the magnification control button 33, the switching of the filter and the control of the scanning magnification can be performed by the control command signal from the connected computer through the computer interface 37. Also,
Through the computer interface 37, power can be supplied from a connected computer.

FIG. 3 is a sectional view of the carriage 17 taken along the line AA 'in FIG. FIG. 3A shows a state in the infrared mode, and FIG. 3B shows a state in the visible light mode.

The carriage 17 is a slender cylindrical body extending in the width direction of the document table (the direction penetrating the paper surface of FIG. 3). It has a slit 18. In the carriage 17, a xenon fluorescent lamp 41, a reflecting mirror 45, and a condenser lens 4 are provided.
7 and a CCD line sensor 49, all of which have an elongated shape extending in the document table width direction.

Light 43 emitted from the xenon fluorescent lamp 41 passes through the slit 41 and irradiates the object 9 placed on the document table 5. Light 43 on platen 5 (object 9)
Are simultaneously limited by the slit 41, and are only narrow, elongated, and small-area areas corresponding to the shape of the slit 41. A part of the light applied to the object 9 is reflected by the object 9, passes through the slit 41 again, reaches the reflecting mirror 45, reflects there, reaches the condenser lens 47,
CCD placed on its image plane by condensing lens 47
The light enters the light receiving surface of the line sensor 49. The light incident on the CCD line sensor 49 is converted into a series of electric signals representing the intensity. This row of electric signals represents one line of the image of the object 9 along the width direction of the document table. The train of electric signals is sent to the output circuit shown in FIG. 2 and is converted into digital data.

A filter switch 55 is arranged between the slit 41 and the reflecting mirror 45. Filter switch 5
5 is provided with an infrared light passing filter 51 for cutting visible light and passing infrared light, and a visible light passing filter 53 for passing visible light and cutting infrared light, and operating the light mode changeover switch 31 shown in FIG. Control circuit 1 in response to
9, one of the two filters 51 and 53 is selectively inserted into the optical path. If the infrared light passing filter 5 is inserted, the infrared light mode for reading the infrared image is set, and the visible light passing filter 53 is set.
Is inserted into the visible light mode for reading the visible light image.

The above-described filters 51 and 53 and the reflecting mirror 45
The lens and the lens 47 are set by the CDD line sensor 49 with the above-described one-line optical image in the elongated light irradiation area of the object 9 (more precisely, on the surface of the object 9 which is in contact with the upper surface of the document table 5). An image forming optical system for forming an image on the light receiving surface is formed. Here, the wavelength of the infrared light in the infrared mode is, for example, 800 nm to 90 assuming that the near infrared region is used.
0 nm, and the wavelength of visible light is 45
0 nm, 530 nm, and 610 nm, and the wavelength difference between infrared light and visible light is large, so that the imaging position of the lens 47 is greatly different between infrared light and visible light (for example, about several mm). Therefore, by compensating for such a difference in the imaging position,
CDD line sensor 4 in both infrared mode and visible light mode
The thickness of a plate made of a material such as glass which constitutes (or holds) the visible light passing filter 53 is adjusted so that an image can be reliably formed on the light receiving surface of the infrared passing filter 51. It is made thicker than required. Thus, the position of the imaging plane is always the same in both the infrared mode and the visible light mode, and the light receiving surface of the CDD line sensor 49 is arranged there. Alternatively, by adjusting the position of the reflecting mirror 45, the lens 47, or the CDD line sensor 49 according to the infrared mode or the visible light mode,
The imaging surface may be made to coincide with the light receiving surface of the CDD line sensor 49.

During image reading, the carriage 17 moves in one direction and scans the entire area of the object 9 with the light irradiation area. At each point during the scan, the CCD line sensor 4
Reference numeral 9 outputs a signal sequence indicating an image of each line of the object. This is repeated, and when the scanning of the entire area of the object 9 is completed, complete image data of the object 9 is obtained. In addition, in addition to the reading mode for reading the complete image data by moving the carriage 17 in one direction, the carriage 17 is reciprocated,
The image reading is performed on the forward path and the return path as described above (two different image data of the same object in the 180 ° direction are obtained).
It is also possible to provide a reading mode in which one image data is completed by rotating the image data by 80 degrees and integrating the image data with the other image data (for example, adding an image value and dividing by two). Also, the infrared image reads one of the visible light images on the outward path of the movement of the carriage 17, and then on the return path (or on the outward path of the carriage 17 once returning to the original position and re-scanning), the infrared image is the other of the visible light images. It is also possible to provide a reading mode in which reading of the image is automatically performed.

In the above configuration, the reflected light from the object 9 is separated by the filters 51 and 53. As a modification, as shown in FIG. The irradiation light to the object 9 may be split by inserting the 51 and 53. Filter 5
The insertion positions of the first and the 53 are located at other places in the optical path, for example, between the reflecting mirror 45 and the lens 47, the lens 47 and the CCD sensor
Between. If the visible light mode is not required, the infrared ray passing filter 51 may be fixedly arranged. In this case, the filter 51 is connected to the lamp 41, the document table 5,
It may be attached to the surface of the reflecting mirror 45, the lens 47 or the CCD line sensor 49.

FIG. 5 shows the spectral characteristics of light emission of the xenon fluorescent lamp 41, and includes both visible light (wavelength 780 nm or less) and infrared light (wavelength 780 nm or more). FIG.
Indicates the spectral characteristics of the sensitivity of the CCD sensor in the near infrared region, and has sensitivity in a wide range from the visible light region to the infrared region. FIG. 7 shows the spectral characteristics of the light transmittance of the filters 51 and 53. As shown by the characteristic curve A, the infrared ray passing filter 51 is substantially infrared (wavelength 780 nm or more).
Only, and the visible light pass filter 53 has a characteristic curve B
As shown by the symbol, substantially only visible light (wavelength 780 nm or less) is passed.

FIG. 8 shows the spectral characteristics of the light that has passed through the infrared pass filter 51 in the infrared mode (the calculated value obtained by multiplying the spectral characteristics of the lamp 41 by the spectral characteristics of the filter 51).
It can be seen that only infrared light passes. FIG. 9 shows the spectral characteristic of the output signal of the CCD sensor 49 in the infrared mode (the spectral characteristic of the lamp 41 × the spectral characteristic of the filter 51 × the calculated value obtained by the spectral characteristic of the CCD sensor 49). It can be seen that an output signal is obtained only when the output signal is obtained.

FIG. 10 shows a read image of the result of reading a wooden letter on which characters are ink-written in the visible light mode of the image scanner 1, and FIG. 11 shows a read image of a result of reading the same wooden letter in the infrared mode. .

In the visible light image shown in FIG. 10, characters written in black ink are hardly readable due to the darkened surface color of the old wooden shingles, the grain, and the attached dirt. On the other hand, in the infrared image shown in FIG. 11, only the ink-written characters appear to be black. In addition, unlike camera photography, the shape of characters can be accurately grasped, which is highly useful for research.

FIG. 12 shows a read image of a pottery sketch drawn with a pencil on grid paper in the visible light mode of the image scanner 1, and FIG. 13 shows a read result of the same sketch read in the infrared mode. 3 shows a read image.

In the visible light image shown in FIG. 12, the sketch itself is hard to see because the surface color and the grid of the graph paper are read together with the sketch. On the other hand, in the infrared image shown in FIG. 13, since only the sketch is read, it is easy to see. In addition, even if the grid disappears, the sketch is read in the correct size and shape, so it is highly useful for research.

The embodiment of the present invention has been described above.
This embodiment is merely an example for explaining the present invention, and is not intended to limit the present invention to only these embodiments. Therefore, the present invention can be implemented in various modes other than the above-described embodiment without departing from the gist thereof. For example, the present invention can be applied to a case where a transmitted light image of an object is read. As a method of switching the light mode, in addition to the method of switching the filter, two types of light sources, a visible light lamp and an infrared lamp, may be prepared and the lighting thereof may be switched. If the lamps are switched at high speed, it is possible to read both a visible light image and an infrared image by one scan. In addition, the present invention can be applied to not only a reading device of a visible light image and an infrared image but also a reading device of a visible light image and an ultraviolet image, and a reading device of a visible light image, an infrared image and an ultraviolet image. Furthermore, the object is irradiated only with ultraviolet rays,
The present invention is also applicable to an apparatus that can read only the fluorescent component reflected from the object. In this case, a filter that irradiates only ultraviolet light from the lamp to the object and allows only visible light (or only infrared light) to pass between the object and the photoelectric conversion device may be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of an infrared image scanner according to an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing components housed inside a casing 3.

FIG. 3 is a cross-sectional view of the carriage 17 taken along the line AA ′ in FIG. 1; FIG.
Indicates a state in the visible light mode.

4 is a cross-sectional view of the carriage 17 taken along the line AA ′ of FIG. 1 in a modified example. FIG. 3A shows a state in an infrared mode, and FIG. 3B shows a state in a visible light mode. Show.

FIG. 5 is a diagram showing spectral characteristics of light emission of a xenon fluorescent lamp 41.

FIG. 6 is a diagram showing spectral characteristics in the near infrared region of the sensitivity of the CCD sensor.

FIG. 7 shows the spectral characteristics of the light transmittance of the filters 51 and 53. Curve A shows the characteristics of the infrared light passing filter 51 and curve B shows the characteristics of the visible light passing filter.

FIG. 8 is a diagram showing the spectral characteristics of light that has passed through the infrared light passing filter 51 in the infrared mode (the calculated value obtained by multiplying the spectral characteristics of the lamp 41 × the spectral characteristics of the filter 51).

FIG. 9 shows the spectral characteristics of the output signal of the CCD sensor 49 in the infrared mode (the spectral characteristics of the lamp 41 × the spectral characteristics of the filter 51 × the calculated value obtained by the spectral characteristics of the CCD sensor 49).
FIG.

FIG. 10 is a view showing a read image as a result of reading in a visible light mode a wooden letter in which characters are ink-written.

FIG. 11 is a diagram showing a read image as a result of reading the same tree in the infrared mode.

FIG. 12 is a view showing a read image as a result of reading in a visible light mode a pottery sketch drawn on a graph paper with a pencil.

FIG. 13 is a view showing a read image as a result of reading the sketch in the infrared mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image scanner 3 Casing 5 Document table 9 Object 17 Carriage 18 Slit 19 Control circuit 21 Output circuit 23 Power supply circuit 27 Battery 31 Light mode switch 41 Xenon fluorescent lamp 49 CCD line sensor 51 Infrared light passing filter 53 Visible light passing filter 55 Switching vessel

Claims (7)

[Claims] A light source for generating light including infrared rays; a limited area irradiating means for irradiating light from the light source to a small area of a part of the entire area of the object; Scanning means for moving the small area irradiated with the light so as to scan; receiving light reflected or transmitted from predetermined positions in the small area irradiated with the light, and Optical imaging means for forming an optical image, at each time point during scanning, for receiving an optical image at each predetermined position in the small area formed by the optical imaging means and converting it into an electric signal, A photoelectric conversion unit having sensitivity to infrared light; and an infrared ray pass filter for filtering light beams from the light source through the object to the photoelectric conversion unit so that light received by the photoelectric conversion unit is substantially limited to infrared light. H Image reading apparatus comprising a filter means, and output means for generating and outputting an image data of the object by receiving an electrical signal from the photoelectric conversion means. 2. The light source emits both visible light and infrared light, the photoelectric conversion means has sensitivity to both visible light and infrared light, and the light received by the photoelectric conversion means is substantially Visible light passing filter means for filtering light rays from the light source through the object to the photoelectric conversion means so as to be limited to visible light, and switching between the infrared light passing filter means and the visible light passing filter means 2. The image reading apparatus according to claim 1, further comprising a filter switching means for selectively using the image reading apparatus. 3. The optical image forming means according to which one of the infrared light passing filter means and the visible light passing filter means is used, the optical image forming means accurately converts an image at each predetermined position in the small area into the photoelectric conversion means. 3. The image reading apparatus according to claim 2, further comprising an optical characteristic adjusting unit that adjusts an image forming characteristic of the optical image forming unit so that an image is formed on the light receiving surface. 4. A power supply using a battery or receiving power from an interface for data communication with an external computer.
An image reading device according to claim 1. 5. A light source for generating light including at least one of visible light, infrared light, and ultraviolet light, and a light source for irradiating light from the light source to only a small area of a whole area of the object. Area irradiating means, scanning means for moving the small area irradiated with the light so as to scan the entire area, and receiving light reflected or transmitted from predetermined positions in the small area irradiated with the light. Optical imaging means for forming an optical image at each predetermined position in the small area, and receiving an optical image at each predetermined position in the small area formed by the optical imaging means at each time during scanning. Photoelectric conversion means having sensitivity to visible light, at least one of infrared light and ultraviolet light, and one type of light received by the photoelectric conversion means selected from visible light, infrared light and ultraviolet light. As substantially limited to light, light emitted from the light source, or light mode selection means for selecting light from the light source through the object to the photoelectric conversion means, and from the photoelectric conversion means And an output unit for generating and outputting image data of the object in response to the electric signal. 6. The filtering means for filtering the light from the light source through the object to the photoelectric conversion means so that only the selected one type of light passes therethrough. The image reading device according to claim 5, further comprising: 7. The light source has a visible light lamp that emits visible light, at least one of an infrared lamp that emits infrared light, and an ultraviolet lamp that emits ultraviolet light, and the light mode selection means is a lamp that the light source has 6. The image reading device according to claim 5, further comprising a selection lighting unit for selectively lighting one of the lamps selected from the lamps.