JP2010231437A - Code symbol reader - Google Patents

Abstract

A code symbol reader capable of reliably reading a code symbol is provided.
In an opening portion 200 of a housing 110 opened in a code symbol reading region defined by an imaging lens 122 and an area image sensor as an imaging region in which a resolution capable of analyzing a code symbol by an image processing device 140 is obtained. The low-reflection transparent member 150 that reduces the reflection of the illumination light emitted from the illumination device 130 to the area image sensor is provided. Thereby, if the code symbol attached to the product is pressed against the low reflection transparent member 150, the product is surely arranged in the code symbol reading area, and the code symbol can be read reliably.
[Selection] Figure 2

Description

  The present invention relates to a code symbol reader.

  As a code symbol reader that acquires an image of a code symbol attached to a product and outputs product data, there is one using an area image sensor such as a CCD (Charge Coupled Device Image Sensor) image sensor (see Patent Document 1). ). Such a code symbol reader extracts image information of a target barcode from image data obtained by a CCD image sensor, and analyzes the image information to obtain product data.

JP 2005-025311 A

  By the way, in the conventional code symbol reader, since the imaging lens is often a fixed focal point from the viewpoint of cost reduction, there is a problem that a reading area for barcode symbols and the like is limited. Therefore, there is a demand for a code symbol reader that can reliably guide a product with a barcode symbol or the like to a reading area and reliably read the barcode symbol or the like.

  The present invention has been made in view of the above, and an object of the present invention is to provide a code symbol reader capable of reliably reading a code symbol.

  In order to solve the above-described problem and achieve the object, the present invention forms an image of reflected light from a code symbol to be read on an area image sensor by an imaging lens, and the code symbol imaged by the imaging lens. In the code symbol reading device for reading an image by the area image sensor, a housing having an opening located in the code symbol reading region, an illumination device for irradiating the code symbol reading region with illumination light, and A low-reflection transparent member that is provided in the opening and reduces reflection of illumination light emitted from the illumination device to the area image sensor.

  According to the present invention, a product having a low-reflection transparent member that reduces reflection of illumination light irradiated from an illumination device with respect to an area image sensor is provided in a product in an opening of a housing that opens in a code symbol reading area. If the attached code symbol is pressed against the transparent member having low reflection, the product is surely arranged in the code symbol reading area, and the code symbol can be read reliably. Further, when reading a code symbol, there is an effect that a low-reflection transparent member can be used as a mark for an operation for reading the code symbol.

  Exemplary embodiments of a code symbol reading apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

  An embodiment of the present invention will be described with reference to FIGS. The present embodiment is an example in which a bar code reader provided in a vertical bar code scanner is applied as a code symbol reader.

  FIG. 1 is a perspective view showing an appearance of a barcode scanner 10 according to an embodiment of the present invention. The barcode scanner 10 is provided with an elevating function for changing the height of the barcode reader 100 which is a code symbol reader, and facilitates the reading operation by the operator. As shown in FIG. 1, the barcode scanner 10 is erected on a soccer base 11 (or a counter base) on which a basket or the like into which goods are put is placed. The bar code scanner 10 is provided with a pair of support columns 13 each having a guide groove 12 and a bar code reader 100 that is guided along the guide groove 12 so as to be movable up and down. A display 16 and a keyboard 17 are provided above the bar code reader 100.

  In the barcode scanner 10 according to the present embodiment, an operator places a product in front of the barcode reader 100 and reads a barcode attached to the product.

  FIG. 2 is a schematic cross-sectional view showing the structure of the barcode reader 100. The barcode reading apparatus 100 is formed of a front side cover member 111 arranged on the imaging region F side where the product is arranged, and a back side cover member 112 arranged in combination on the side opposite to the imaging region of the front side cover member 111. A box-shaped housing 110 is provided.

  In the housing 110, an imaging device 120 including a CCD (Charge Coupled Device Image Sensor) imaging device, an illumination board 130 that is an illumination device that irradiates the imaging region F with illumination light, and a product acquired by the CCD imaging device. An image processing board 140, which is an image processing apparatus that extracts a barcode area from image data and obtains a product code, is provided.

  The front cover member 111 has a concave portion 160 formed inwardly at the center of the surface plate 111a in addition to the surface plate 111a arranged closest to the imaging region F. The recessed portion 160 is formed with a quadrangular pyramid wall whose cross-sectional area decreases toward the back, and an opening 113 is formed in the innermost portion of the recessed portion 160.

  The imaging apparatus 120 includes a CCD imaging device that is an area image sensor and a CCD imaging device driving circuit, and an imaging lens 122 having a focal length f that forms an image of the imaging region F on the CCD imaging device. Become.

  The image processing board 140 is an image processing device, and recognizes one piece of frame data that can read the entire barcode from the moving image data output from the imaging device 120. Then, the image processing board 140 decodes the recognized barcode and outputs it as decoded data.

  The illumination board 130 is an illumination device and is disposed on the back side of the opening 113. Here, FIG. 3 is a front view showing the lighting board 130. As shown in FIG. 3, an opening 133 for photographing the imaging device 120 is opened on the substrate 134 of the lighting board 130. A plurality of LED light emitting elements 131 are arranged on the substrate 134 of the lighting board 130 located in the opening 113 at the innermost part of the recessed portion 160 so as to surround the opening 133. Thereby, the plurality of LED light emitting elements 131 irradiate light to the illumination area I wider than the imaging area F of the imaging device 120.

  Moreover, the low reflection glass 150 which is a low reflection transparent member is arrange | positioned so that the opening part 200 of the recessed part 160 may be plugged up on the same surface as the surface plate 111a of the front side cover member 111. Here, the low reflection glass 150 is a low reflection transparent member made of glass or plastic. Note that “transparent” does not need to be transparent to human eyes, and may be transparent to the imaging device 120. As the low reflection glass 150, for example, low reflection glass manufactured by Asahi Glass Co., Ltd. can be used.

  The reason why the low reflection glass 150 is used is as follows. When normal glass is used instead of the low reflection glass 150, the back surface of the normal glass reflects a large amount of LED light from the LED light emitting element 131 as shown in FIG. Since the reflected light X enters the CCD image sensor via the imaging lens 122, the image captured by the imaging device 120 is an image as shown in FIG. As a result, the lightness value representing the lightness of the bar code as a waveform includes a lack of image information as shown in FIG. 6 and adversely affects the decoding of the bar code. On the other hand, when the low reflection glass 150 is used as in the present embodiment, the reflected light is small and has little influence on the brightness waveform of the barcode. Therefore, the brightness value of the LED light that adversely affects the decoding of the barcode. There is no reflection.

  By the way, the imaging range of the CCD imaging device on the imaging substrate 121 of the imaging device 120 is determined by the characteristics of the imaging lens 122. The imaging lens 122 of the present embodiment is a fixed focus lens, and the focus position (position where the focus is best) is at a position away from the lens tip by a certain distance. When the product that is the imaged object is placed at this focal position, the resolution is the highest, the image can be clearly captured, and the product that is the imaged object is placed in the direction approaching or moving away from the CCD image sensor from the focal position. The image is out of focus and the resolution is low. In order to decode the bar code, it is necessary to measure the width of each color (for example, black and white) bar forming the bar code from the image data of the product acquired by the CCD image pickup device. Therefore, a range of a certain resolution or higher is the barcode reading area A, and the range is uniformly located in a substantially circular shape with the focus position at the center.

  Here, the barcode reading area A is an area in which the resolution of an image captured by the imaging device 120 is equal to or higher than a predetermined value d, and is located with the focal position P interposed therebetween as shown in FIG. This is an area between the lens side limit Pc and the anti-lens side limit Pf. The reading area A is determined by the specifications of the imaging device 120 such as the element pitch of the CCD imaging device, the focal length f of the imaging lens 122, and the arrangement position of the imaging device 120 on the housing 110.

  That is, when the reading depth of the barcode to be read indicating the distance between the barcode to be read and the imaging device 120 is within the reading area A, the barcode can be read satisfactorily.

  In the present embodiment, the barcode reading area A is set so that the position of the lens side limit Pc substantially coincides with the position of the surface plate 111 a of the front cover member 111, that is, the top surface of the low reflection glass 150. In the present embodiment, the reading area A is set to be a sufficiently wide area including the arrangement position of the low reflection glass 150 (that is, the lens side limit Pc).

Here, the sufficiently wide area is a range in which the product can be placed without being particularly conscious of the reading area A when the operator places the product. In the present embodiment, the distance a from the arrangement position of the surface plate 111a (low reflection glass 150) (that is, the lens side limit Pc) to the anti-lens side limit Pf is about 150 mm, and from the in-focus position P to the anti-lens side limit Pf. distance _{a 1} of approximately 100 mm, the distance _{a 2} from the lens side limit Pc is about 50 mm.

  Further, the positional relationship between the lens side limit Pc and the surface plate 111 a (low reflection glass 150) is determined by the focal length f of the imaging lens 122 and the position where the imaging device 120 is disposed in the housing 110. In the present embodiment, the distance b from the end surface of the imaging lens 122 to the in-focus position P, which is the above condition, is about 110 mm. Further, the shape and depth dimension of the recessed portion 160 are selected so as not to obstruct the shooting of the imaging device 120 and the illumination of the lighting board 130 in consideration of the arrangement positions of the imaging device 120 and the illumination board 130. Is done.

  Therefore, in the barcode reading apparatus 100 according to the present embodiment, it is possible to read the barcode by placing the product in a wide range including the position close to the placement position of the surface plate 111a (low reflection glass 150). In the present embodiment, since the imaging region F is included in the illumination region I of the illumination board 130, no region in the imaging region F that is not irradiated with light from the illumination board 130 is generated. Further, in the present embodiment, the housing 110 is provided with the recessed portion 160, and the low reflection glass 150 is disposed so as to close the recessed portion 160 on the same surface as the surface plate 111a of the front cover member 111. Therefore, the low reflection glass 150 can restrict the user from holding the product outside the barcode reading area A (inside the recessed portion 160 of the housing 110), and the barcode can be read reliably. It is possible to provide an easy-to-use bar code reader 100 that can give the operator a sense of security.

  In the present embodiment, the top surface of the low-reflection glass 150 is substantially coincident with the position of the lens side limit Pc of the barcode reading area A. However, it is not always necessary to substantially coincide with the low-reflection glass. It suffices if the top surface of 150 is positioned in the barcode reading area A.

  According to the bar code scanner 10 according to the present embodiment, when the operator causes the bar code reader 100 to read the bar code of the product, the operator stands on the inner side of the soccer base 11 and is a shopping cart placed on the upstream side of the lane. Take out the purchased items one by one. Then, when the extracted product has a barcode, the operator holds the barcode toward the opening 200 of the barcode reader 100 and causes the imaging device 120 to read the barcode.

  In the barcode reader 100, the product image read by the imaging device 120 is sent to the image processing board 140, and the barcode image is extracted and analyzed by the image processing board 140. The analyzed product code is a POS terminal or the like. The product is registered by being output to the host device.

  When the barcode is read correctly, a confirmation sound for the completion of reading is emitted from the barcode scanner 10, and the operator confirms this confirmation sound and puts the product into a shopping cart arranged downstream of the lane. .

  On the other hand, if the bar code cannot be read for some reason, the operator holds the bar code placed on the product again over the bar code reader 100 to read the bar code. At this time, the operator generally moves the product closer to press the product closer to the opening 200 of the front cover member 111 than the previous time when reading failed. According to the barcode reader 100 of the barcode scanner 10 of the present embodiment, since the low reflection glass 150 is disposed so as to close the recessed portion 160, a small product enters the recessed portion 160. Since it will not be outside the reading area A, if the bar code attached to the product is pressed against the low reflection glass 150, the product is surely arranged in the reading area A, and the bar code is reliably read. Can be made. That is, when reading a barcode, the low reflection glass 150 serves as a mark for an operation for reading the barcode.

  In addition, even if the barcode is difficult to read at a time because the barcode is wrinkled or the barcode is small, the barcode is simply moved close to the low reflection glass 150 of the barcode reader 100. Since the reading can be performed more reliably, the operator can be provided with a sense of security, and the barcode reader 100 can be easily used.

  As described above, according to the present embodiment, the limit on the lens side of the barcode reading area defined by the imaging lens 122 and the imaging substrate 121 is obtained as an imaging area in which a resolution capable of analyzing the barcode by the image processing board 140 is obtained. The low-reflection glass 150 that reduces the reflection of the illumination light emitted from the illumination board 130 to the area image sensor is provided in the opening of the casing 110 that is substantially coincident, thereby reducing the reflection of the barcode attached to the product. If pressed against the glass 150, the product is reliably placed in the barcode reading area, and the barcode can be reliably read. Further, when reading a barcode, the low reflection glass 150 can be used as a mark for an operation for reading the barcode.

  In the present embodiment, a barcode is applied as a code symbol. However, the present invention is not limited to this, and it is needless to say that various code symbols such as a two-dimensional code can be applied.

1 is a perspective view showing an external appearance of a barcode scanner according to an embodiment of the present invention. It is a schematic sectional drawing which shows the structure of a barcode reader. It is a front view which shows an illumination board. It is a schematic diagram which shows the light reflection at the time of arrange | positioning normal glass. It is a schematic diagram which shows an example of a captured image. It is a graph which shows an example of the brightness value which represented the brightness of the barcode with the waveform.

DESCRIPTION OF SYMBOLS 100 Code symbol reader 110 Case 120 Area image sensor 122 Imaging lens 130 Illumination device 140 Image processing device 150 Low reflection transparent member 200 Opening

Claims (5)

In the code symbol reading apparatus, the reflected light from the code symbol to be read is imaged on the area image sensor by the imaging lens, and the code symbol image formed by the imaging lens is read by the area image sensor.
A housing with an opening located in the code symbol reading area;
An illumination device for illuminating the code symbol reading area with illumination light;
A low reflection transparent member that is provided in the opening of the housing and reduces the reflection of the illumination light emitted from the illumination device with respect to the area image sensor;
A code symbol reading apparatus comprising: The transparent member reduces the influence of reflected light of illumination light emitted from the illumination device on the brightness waveform of the code symbol imaged by the area image sensor.
The code symbol reader according to claim 1. The illuminating device has a plurality of LED light emitting elements arranged around the area image sensor.
The code symbol reader according to claim 1. The illumination device irradiates illumination light to an illumination area wider than the imaging area by the imaging lens and the area image sensor,
The code symbol reader according to claim 1. The housing includes the image processing device.
The code symbol reader according to claim 1.

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