JP4976433B2 - Code symbol reader - Google Patents

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.

  By the way, in a conventional code symbol reader that reads a barcode using laser light, red laser light having a peak wavelength of about 635 nm is used. For this reason, the bar codes of products on the market are printed in a color that reduces the bar reflectivity with a light source having a wavelength of about 635 nm. Therefore, even in a code symbol reader using an area image sensor, a red LED having a wavelength of about 635 nm is arranged as a light source for irradiating light in an imaging range.

  However, in the case of a code symbol reader in which a red LED is arranged as a light source for irradiating light in the imaging range, the red light is very dazzling and dangerous for human eyes, so it makes the user uncomfortable. Or there is a problem of giving fatigue from a sense of tension.

  When the wavelength of the light source is changed, there arises a problem that a barcode printed with a color other than the color whose reflectance decreases when the light source is 635 nm cannot be imaged.

  The present invention has been made in view of the above, and does not make a user uncomfortable or give fatigue from a sense of tension, and various image processing apparatuses existing in the current market. It is an object of the present invention to provide a code symbol reading apparatus capable of obtaining an image in which a color bar code is secured with a contrast between a bar necessary for image processing and a background.

In order to solve the above-mentioned problems and achieve the object, the present invention connects reflected light from a code symbol to be read attached to a product arranged in a code symbol reading area to an area image sensor by an imaging lens. in code symbol reading device which is erected read by the image, an LED light emitting element which irradiates 4 50 nm and near the two light emission spectrum having a peak wavelength in the vicinity of 580 nm, the vicinity of 450nm and peak wavelength The region including the code symbol reading region is irradiated with blue component light and light with reduced red component having a peak wavelength near 580 nm .

  According to the present invention, light of an emission spectrum having two peak wavelengths near 450 nm and 580 nm, that is, a blue component peak wavelength and a red component peak wavelength with respect to the code symbol reading region of the area image sensor. By providing an LED light emitting element that irradiates light having two peak wavelengths, light having a peak wavelength near 580 nm from the LED light emitting element is compared with red light from a general red LED light emitting element. Since it is not dazzling to human eyes, it does not make the user uncomfortable or does not give fatigue from a sense of tension, and the peak wavelength near 580 nm of the LED light emitting element is the peak wavelength of the red LED light emitting element. Because of the closeness, various color code symbols that exist in the current market in image processing devices can be used for image processing. It is possible to obtain a photographed secured contrast, an effect that.

FIG. 1 is a perspective view showing an appearance of a barcode scanner according to an embodiment of the present invention. FIG. 2 is a schematic sectional view showing the structure of the barcode reader. FIG. 3 is a front view showing the lighting board. FIG. 4 is a graph showing an emission spectrum. FIG. 5 is a schematic diagram showing light reflection when ordinary glass is arranged. FIG. 6 is a schematic diagram illustrating an example of a captured image. FIG. 7 is a graph showing an example of a lightness value in which the lightness of the barcode is represented by a waveform.

  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 image pickup device 120 including a CCD image pickup device, an illumination board 130 that is an illuminating device that irradiates the image pickup region F with illumination light, and a barcode region from product image data acquired by the CCD image pickup device. And an image processing board 140 that is an image processing apparatus that extracts and acquires a product code.

  In the front cover member 111, a surface plate 111a located closest to the imaging region side of the casing is disposed on the imaging region F side, and a concave portion 160 is formed in the center of the surface plate 111a. Has been. 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 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.

  In the present embodiment, a light bulb color LED light emitting element is used for the plurality of LED light emitting elements 131 arranged on the substrate 134 of the illumination board 130. As shown in FIG. 4, the light bulb color LED light emitting element has two peak wavelengths (450 nm and 580 nm) of a red component and a blue component.

  Since the peak wavelength (580 nm) of the red component of the light bulb color LED light emitting element is close to the peak wavelength (about 635 nm) of the red LED light emitting element, barcodes of various colors existing in the current market on the image processing board 140 are imaged. It is possible to obtain an image in which the contrast between the bar and the base necessary for processing is ensured. Light bulb color light from such a light bulb color LED light emitting element is not dazzling to human eyes compared to red light from a general red LED light emitting element, so it does not make the user uncomfortable or from tension Does not give fatigue. Therefore, in order to reduce glare, the light intensity of the blue component should be increased by reducing the light intensity of the red component while ensuring the barcode reading performance.

  On the other hand, the peak wavelength (450 nm) of the blue component of the light bulb-colored LED light-emitting element is the contrast necessary for image processing even for a barcode with a white base and red bar that cannot be image-processed with a general red LED light-emitting element. Can be obtained.

  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.

  Moreover, the low reflection glass 150 is arrange | positioned so that the opening part 200 of the recessed part 160 may be plugged up by the same surface as the surface plate 111a of the front side cover member 111. FIG. 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 this 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 barcode as a waveform includes a lack of image information as shown in FIG. 7, which adversely affects the decoding of the barcode. 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.

  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. At this time, the light bulb colored light emitted from the light bulb colored LED light emitting element irradiated in the operator direction from the barcode scanner 10 is not dazzling to human eyes, so that the operator does not feel uncomfortable or nervous.

  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 light of the emission spectrum having two peak wavelengths near 450 nm and 580 nm, that is, the blue component peak wavelength and the red component with respect to the imaging region of the area image sensor. By providing a light bulb-colored LED light emitting element 131 that irradiates light having two peak wavelengths, light having a peak wavelength near 580 nm from the light bulb colored LED light emitting element 131 is a general red color. Since it is not dazzling to human eyes compared to red light from LED light emitting elements, it does not make the user uncomfortable or does not give fatigue from a sense of tension, and the bulb color LED light emitting element 131 near 580 nm Since the peak wavelength of the image processing board 140 is close to the peak wavelength of the red LED light-emitting element, there are various types existing in the current market. It is possible to obtain a photographed secured the contrast between the bar and the base bar to the desired code to the image processing of the color, an effect that.

  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.

DESCRIPTION OF SYMBOLS 100 Code symbol reader 120 Area image sensor 131 LED light emitting element of a light bulb color 140 Image processing apparatus

JP 2005-025311 A

Claims (4)

In a standing code symbol reader that reads reflected light from a code symbol to be read attached to a product arranged in a code symbol reading area by forming an image on an area image sensor by an imaging lens,
4 comprising an LED light emitting element that emits light of an emission spectrum having two peak wavelengths near 50 nm and 580 nm ;
Irradiating a region including the code symbol reading region with light of a blue component having a peak wavelength near 450 nm and light having a reduced red component having a peak wavelength near 580 nm;
A code symbol reader characterized by the above. A plurality of the LED light emitting elements are arranged around the area image sensor.
The code symbol reader according to claim 1. Comprising a housing with an opening located in the code symbol reading area;
The code symbol reader according to claim 1. A low reflection transparent member that is provided in the opening and reduces reflection of the light emitted from the LED light emitting element to the area image sensor;
The code symbol reader according to claim 3, further comprising:

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