JP2009059214A - Paper sheet discrimination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate paper sheets by simply acquiring highly accurate image data even when a paper sheet is irregularly conveyed. <P>SOLUTION: A light emitting/receiving element irradiates a paper sheet with light of at least two wavelengths, i.e. visible rays and infrared rays and receives reflected visible rays and reflected infrared rays obtained by respectively reflecting the visible rays and infrared rays by the paper sheet. A correction processing part receiving light receiving data corrects the intensity distribution of the reflected visible rays by using the reflected infrared rays and a correction value determined from a prescribed threshold in an area where the intensity of the reflected infrared rays is the prescribed threshold or more. Then, a discrimination processing part discriminates the paper sheet by using the corrected intensity distribution of the reflected visible rays. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paper sheet identification device that identifies the type of paper sheet by irradiating light to the conveyed paper sheet, and in particular, even if the paper sheet is fluttered, In particular, the present invention relates to a paper sheet identification apparatus capable of identifying paper sheets by acquiring highly accurate image data.

  2. Description of the Related Art There is known a paper sheet identification device that irradiates light on paper sheets such as gift certificates and banknotes and identifies the types of these paper sheets. In such a paper sheet identification device, it is generally performed that a paper sheet is transported by a transport mechanism and a pattern of the paper sheet is read by an optical sensor attached to the transport path.

  In recent years, from the viewpoint of preventing counterfeiting, such paper sheets are often printed using ink that reacts to UV (ultraviolet) light or ink that reacts to IR (infrared) light. For this reason, the paper sheet identification apparatus has been provided with a mechanism for emitting / receiving light of a plurality of wavelengths.

  By the way, in the conveyance path in which the paper sheet is conveyed, a predetermined clearance (gap) is ensured between the paper sheet and the upper surface / lower surface of the conveyance path in order to convey the paper sheet smoothly. However, if there is such clearance, there is a problem that unclear portions occur in the acquired image data because the paper sheets flutter in the conveyance path.

  For this reason, even when there is a flutter of paper sheets, a method for accurately reading the pattern of the paper sheets has been proposed. For example, in Patent Document 1, light reception data when the distance between the light source and the target object deviates from a reference distance is actually measured to calculate a deviation, and the light reception data is corrected using a table in which the deviation is stored. Thus, a technique for suppressing variation in received light data due to flapping of an object is disclosed.

JP 2005-190370 A

  However, since the technique of Patent Document 1 corrects the received light data based on the correction data measured in advance, there is a problem that the correction accuracy deteriorates due to the aging of the light source and the influence of environmental changes. In addition, there is a problem that it takes time and effort to acquire a large amount of correction data, and a problem that a memory area for storing correction data becomes bulky.

  Therefore, how to manufacture a paper sheet identification device that can easily acquire high-accuracy image data and identify paper sheets even if the paper sheets flutter. Has become a major issue.

  The present invention has been made to solve the above-described problems caused by the prior art, and even when paper sheets are fluttered, it is possible to easily obtain high-precision image data and obtain paper sheets. It is an object of the present invention to provide a paper sheet identification device that can be identified.

  In order to solve the above-described problems and achieve the object, the present invention provides a paper sheet identification device for identifying the type of the paper sheet by irradiating light to the conveyed paper sheet, Light irradiating means for irradiating a paper sheet with light of at least two wavelengths of visible light and infrared light, and light reception for receiving reflected visible light and reflected infrared light reflected by the paper sheet, respectively. And correction means for correcting the intensity distribution of the reflected visible light based on the intensity distribution of the reflected infrared light.

  Further, the present invention is characterized in that, in the above invention, the correcting means corrects the intensity distribution of the reflected visible light only in a region where the intensity of the reflected infrared ray is equal to or greater than a predetermined threshold value.

  Further, in the present invention according to the above invention, the correction unit calculates a correction amount at each position related to the intensity distribution of the reflected visible light based on the intensity of the reflected infrared light and the predetermined threshold, and the correction amount The intensity distribution of the reflected visible light is corrected based on the above.

  Further, the present invention, in the above invention, further comprises an identification target area storage means for storing an identification target area specified for each paper sheet, wherein the correction means is only for the area included in the identification target area. The intensity distribution of the reflected visible light is corrected.

  According to the present invention, the paper sheet is irradiated with light having at least two wavelengths of visible light and infrared light, the reflected visible light and reflected infrared light reflected by the paper sheet are respectively received and reflected. The intensity distribution of reflected visible light was corrected based on the infrared intensity distribution. That is, highly accurate reflected visible light image data can be acquired by correcting the intensity distribution of reflected visible light using reflected infrared rays that are likely to cause an output level difference depending on the distance between the light source and the paper sheet. Therefore, even if the paper sheets are fluttered, it is possible to easily acquire high-precision image data and identify the paper sheets.

  In addition, according to the present invention, the intensity distribution of the reflected visible light is corrected only for the region where the intensity of the reflected infrared ray is equal to or greater than the predetermined threshold value, so that the intensity of the reflected infrared ray is compared with the predetermined threshold value. There is an effect that the correction target region can be determined.

  Further, according to the present invention, the correction amount at each position related to the intensity distribution of the reflected visible light is calculated based on the intensity of the reflected infrared light and the predetermined threshold, and the intensity distribution of the reflected visible light is calculated based on the calculated correction amount. Since the correction is performed, the correction amount can be determined without preparing a table in which correction values and the like are stored in advance.

  Further, according to the present invention, the identification target area designated for each paper sheet is stored, and the intensity distribution of the reflected visible light is corrected only for the area included in the identification target area. By performing correction only for the minimum necessary area, the processing load of the correction process can be reduced.

  Exemplary embodiments of a paper sheet identification apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, a case where the paper sheet to be identified is a banknote will be described. However, other paper sheets such as gift certificates and postcards can be identified. In the following, a case where a paper sheet is identified using a line sensor will be described, but not limited to a line sensor, a point sensor or a spot sensor may be used.

  First, feature points of the paper sheet identification apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating characteristics of the paper sheet identification apparatus according to the present embodiment. In addition, (A) in the figure shows a top view of the conveyance path provided in the paper sheet identification device, and (B) in the figure shows a side view of the conveyance path.

  In addition, as shown to (A) of the figure, the line sensor is provided in the orthogonal | vertical direction with respect to the conveyance direction of the banknote conveyed by the lower surface of a conveyance path. This line sensor is composed of a light receiving / light emitting element 2 that irradiates light to a conveyed paper sheet and receives reflected light from the paper sheet. Note that the light emitting element and the light receiving element may be provided separately.

  As shown in FIG. 1B, a clearance (gap) for smoothly transporting paper sheets is provided between the upper surface of the transport path and the lower surface of the transport path. For example, this clearance is 2 mm. Set to degree. For this reason, the transported paper sheets “flutter” between the upper surface of the transport path and the lower surface of the transport path. Due to the flapping, the distance between the line sensor and the paper sheet is not constant.

  Therefore, in the image data of the paper sheet obtained through the line sensor, a portion where the pattern of the paper sheet is clear and a portion where the pattern is unclear are generated. However, in order to identify the type of paper sheet with high accuracy, it is not preferable that an unclear portion is generated in the image data.

  Therefore, in the paper sheet identification apparatus according to the present embodiment, visible light and infrared light are applied to the paper sheet, and the intensity distribution of the reflected infrared image data 21 obtained from the reflected light of the infrared light is used to detect visible light. The intensity distribution of the reflected visible light image data 22 obtained from the reflected light is corrected. In the corrected reflected visible light image data 23 corrected in this way, the image quality of the unclear portion resulting from the flapping of the paper sheet is improved. Therefore, when the identification processing is executed using the corrected reflected visible light image data 23, the paper sheets can be identified with high accuracy.

  Specifically, as shown in (1) of FIG. 1, light of two wavelengths of visible light (for example, green) and infrared light is irradiated onto the paper sheet. As shown in (2) of FIG. 1, if the reflected light of these lights is received, the reflected infrared image data 21 related to the reflected infrared light and the reflected visible light image data 22 related to the reflected visible light are obtained. Generate each.

  Subsequently, as shown in (3) of FIG. 1, the reflected visible light image data 22 is corrected using the reflected infrared image data 21. Details of such correction processing will be described later. Then, a paper sheet identification process is executed using the corrected reflected visible light image data 23 corrected by the correction process.

  As described above, in the paper sheet identification apparatus according to the present embodiment, the reflected visible light image data 22 is corrected using the intensity distribution of the reflected infrared image data 21, and the reason for performing such correction processing is the reflected infrared light. This is because the reaction corresponding to the distance between the paper sheet and the light source is more likely to appear in the image data 21 than the reaction corresponding to the pattern of the paper sheet.

  FIG. 2 is a diagram showing the relationship between the reflected infrared image data and the reading distance. As shown in the figure, the reflected infrared image data 21 obtained from the paper sheet conveyed while fluttering in the conveyance path has a thin portion (strong intensity). As described above, the reflected infrared image data 21 is likely to have a reaction corresponding to the distance between the paper sheet and the light source. Therefore, the “part where the image is thin” is an area far from the element (light emitting element). Correspond.

  In the paper sheet identifying apparatus according to the present embodiment, the intensity at each coordinate position in the intensity distribution of the reflected infrared image data 21 is compared with a predetermined threshold, and an area equal to or greater than the predetermined threshold is set as a correction target area. Further, the correction amount is calculated from the intensity of each coordinate position included in the correction target region and a predetermined threshold value. Therefore, compared to a method in which data for determining the correction amount and the correction amount itself are stored in the table in advance, the light source is less susceptible to changes due to aging and environmental changes.

  That is, the correction method used by the paper sheet identification apparatus according to the present embodiment can determine the correction amount and the correction target area only from the data acquired when scanning the paper sheet. Moreover, since the correction method used by the paper sheet identification apparatus according to the present embodiment is simple, the processing load associated with the correction process can be reduced.

  Next, the configuration of the paper sheet identification apparatus according to the present embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating the configuration of the paper sheet identification apparatus according to the present embodiment. In FIG. 3, only the configuration necessary for explaining the feature points of the paper sheet identification apparatus according to the present embodiment is shown, and general paper sheets such as a transport mechanism, a display unit, and an output unit are illustrated. A description of the configuration of the identification device is omitted.

  As shown in FIG. 3, the paper sheet identification apparatus 1 according to this embodiment includes a light receiving / light emitting element 2, a control unit 10, and a storage unit 20. The control unit 10 further includes an image input unit 11, a correction processing unit 12, and an identification processing unit 13. The storage unit 20 includes reflected infrared image data 21, reflected visible light image data 22, and the like. The corrected reflected visible light image data 23 and the template data 24 are stored.

  The light receiving / light emitting element 2 is an element that irradiates light on the banknote and receives light reflected on the banknote, and includes a light emitting element such as an LED (light emitting diode) and a light receiving element such as a photodiode. The The light receiving / emitting element 2 can receive the reflected visible light and the reflected infrared light separately, for example, by shifting the timing of irradiating visible light and the timing of irradiating infrared light (lights alternately). .

  In this embodiment, the light receiving / emitting element 2 emits light having two wavelengths of green visible light and infrared light, but visible light other than green may be used, such as green and red. A plurality of visible rays may be irradiated.

  The control unit 10 receives the output data from the light receiving / light emitting element 2, performs correction processing on the image data generated from the received output data, and performs paper sheet identification processing based on the corrected image data. It is a processing unit.

  The image input unit 11 receives output data from the light receiving / light emitting element 2, generates a reflected infrared image data 21 and a reflected visible light image data 22 from the received output data, and performs processing to store in the storage unit 20 It is.

  Specifically, the image input unit 11 uses reflected infrared image data 21 that is scan data of a banknote pattern from output data related to reflected infrared light received from the light receiving / emitting element 2 and output data related to reflected visible light. The reflected visible light image data 22 which is the scan data of the banknote pattern is generated. The generated reflected infrared image data 21 and reflected visible light image data 22 are stored in the storage unit 20.

  The correction processing unit 12 reads the reflected infrared image data 21 and the reflected visible light image data 22 from the storage unit 20, corrects the reflected visible light image data 22 using the reflected infrared image data 21, and corrects the corrected reflected visible light image. It is a processing unit that performs processing for storing the data 23 in the storage unit 20. The details of the correction processing performed by the correction processing unit 12 will be described later with reference to FIGS.

  The identification processing unit 13 reads the corrected reflected visible light image data 23 from the storage unit 20, and compares the read corrected reflected visible light image data 23 with the template data 24 prepared for each bill, thereby comparing the bills. It is a processing unit for identifying the type or true / false.

  The storage unit 20 is a storage unit including devices such as a nonvolatile RAM (Random Access Memory) and a HDD (Hard Disk Drive). The reflected infrared image data 21, the reflected visible light image data 22 and the corrected reflected visible light image data 23 that are unnecessary after use in this embodiment are stored in the volatile RAM, and only the template data 24 is stored in the nonvolatile RAM or It is good also as storing in HDD.

  The reflected infrared image data 21 is image data obtained from reflected infrared light reflected by a banknote, and the reflected visible light image data 22 is image data obtained from reflected visible light reflected by a banknote.

  The corrected reflected visible light image data 23 is correction data obtained by correcting the reflected visible light image data 22 by the correction processing unit 12, and image data obtained by clarifying an unclear area of the reflected visible light image data 22. It is. The corrected reflected visible light image data 23 is used for comparison processing with the template data 24 in the identification processing unit 13.

  The template data 24 is image data relating to the pattern on the front or back side of the banknote. Further, the template data 24 is prepared for the types of banknotes identified by the paper sheet identification device 1. Each template data 24 is preferably image data captured with visible light having the same wavelength as the visible light used in the paper sheet identification apparatus 1.

  Next, details of the correction processing performed by the correction processing unit 12 shown in FIG. 3 will be described with reference to FIGS. First, the configuration of the reflected infrared image data 21 and the reflected visible light image data 22 will be described with reference to FIG. FIG. 4 is a diagram showing the configuration of the reflected infrared image data 21 and the reflected visible light image data 22.

  As shown in the figure, each piece of image data is set data of pixels specified by an X coordinate and a Y coordinate. 4A shows the configuration of the reflected infrared image data 21, and FIG. 4B shows the configuration of the reflected visible light image data 22.

  Then, as shown in FIG. 4, when the pixel value in which the X coordinate and the Y coordinate are both 3 in the reflected infrared image data 21 is A (3, 3), A (3, 3) In the image data, the X coordinate and the Y coordinate correspond to B (3, 3) that is a pixel value of 3. When the value of A (3, 3) satisfies a predetermined condition, the value of B (3, 3) is corrected using the value of A (3, 3).

  Further, the value of A (X, Y) or B (X, Y) is expressed by, for example, 8-bit data, and takes any of 256 levels from 0 to 255. Further, each pixel is expressed as “thin” as the value increases. The reflected infrared image data 21 and the reflected visible light image data 22 are data having a size of “8 bits × the number of read pixels in the transport direction × the number of read pixels in the direction perpendicular to the transport direction”.

  In this embodiment, the case where the pixel value of each pixel is used as it is will be described. However, each image data is divided into blocks including a plurality of pixels, and the total or average of the pixel values calculated in units of blocks. A value may be used.

  Next, the correction procedure performed based on the reflected infrared image data 21 will be described with reference to FIG. FIG. 5 is a diagram illustrating a correction target area. First, a procedure for determining a correction target area from the reflected infrared image data 21 will be described. Assuming that each pixel value of the reflected infrared image data 21 is A (X, Y) and a predetermined threshold value is Z, pixels included in the correction target region satisfy the conditional expression “A (X, Y) ≧ Z”. It becomes. In addition, since it is highly likely that the pixel is less than the threshold value Z, the pixel value of the reflected visible light image data 22 at the corresponding coordinates is used as it is without being included in the correction target region.

  The correction target areas determined in this way are shown in FIGS. As shown in FIG. 5A, since the banknotes transported along the transport path are fluttered in the transport direction, the correction target region (in FIG. 5A) covers all the Y coordinates in parallel with the Y coordinates. In many cases, the correction target area A shown in FIG. However, since the banknotes may be folded or wrinkled, as shown in FIG. 5B, a predetermined closed area (see the correction target area B shown in FIG. 5B) is corrected. There are also cases where the target area is taken. Further, as shown in FIG. 5C, a correction target region (see the correction target region C shown in FIG. 5C) extending across all the coordinates of the X coordinate is generated in parallel with the X coordinate. In some cases.

  Then, the pixel value of the pixel of the reflected visible light image data 22 corresponding to the pixel satisfying the conditional expression “A (X, Y) ≧ Z” in the reflected infrared image data 21 is B (X, Y), and the corrected pixel When the value is b (X, Y), the corrected pixel value b (X, Y) is expressed by the equation “b (X, Y) = B (X, Y) × (Z / A (X, Y)” ”. That is, the pixel value after correction is a value obtained by multiplying the pixel value before correction by the correction amount “Z / A (X, Y)”.

  As described above, in the correction processing according to the present embodiment, the correction target area of the reflected visible light image data 22 is determined by comparing each pixel value of the reflected infrared image data 21 with a predetermined threshold, and the correction target area. The correction amount for each pixel of the reflected visible light image data 22 included in the image is determined. Therefore, compared to a method in which data for determining the correction amount and the correction amount itself are stored in the table in advance, the light source is less susceptible to changes due to aging and environmental changes.

  Next, a processing procedure of correction processing performed by the correction processing unit 12 will be described with reference to FIG. FIG. 6 is a flowchart showing the processing procedure of the correction processing. As shown in the figure, first, the correction processing unit 12 reads the reflected infrared image data 21 and the reflected visible light image data 22 from the storage unit 20 (step S101).

  Subsequently, the correction processing unit 12 determines whether or not the value (pixel value) at each coordinate of the reflected infrared image data 21 is equal to or greater than a predetermined threshold (step S102). If the (pixel value) at each coordinate is equal to or greater than a predetermined threshold (step S102, Yes), a correction amount is calculated (step S103).

  Subsequently, the corresponding coordinate value (pixel value) of the reflected visible light image data 22 is corrected using the calculated correction amount (step S104). In step S102, when the pixel value of the reflected infrared image data 21 is smaller than the predetermined threshold (No in step S102), the process proceeds to step S105 without executing steps S103 and S104.

  When step S104 is completed and when it is determined No in step S105, it is determined whether or not processing has been performed for all coordinates of the reflected infrared image data 21 (step S105). Then, when the processing for all coordinates is completed (Yes in step S105), the corrected reflected visible light image data 23 is output to the storage unit 20 (step S106), and the processing ends.

  On the other hand, if the processing has not been completed for all the coordinates of the reflected infrared image data 21 at step S105 (No at step S105), the processing after step S102 is repeated.

  Next, a case where correction processing is performed by designating a predetermined area in the banknote will be described with reference to FIG. FIG. 7 is a diagram illustrating an identification target area. In the figure, a case where an identification target area is set in advance in the template data 24 stored in the storage unit 20 of FIG. 3 will be described.

  FIG. 7A shows template data 24 in which an identification area A and an identification area B are set. The banknote may be provided with a specially printed part. When light of a predetermined wavelength is irradiated, only the ink of the part reacts to the irradiated light. In addition, it may be possible to perform highly accurate identification only by identifying a predetermined portion of a bill.

  Therefore, it is useful to designate “identification target area” in the template data 24 or the like. For example, as shown in FIG. 7A, a case where “identification target area A” and “identification target area B” are designated will be described. As shown in FIG. 7B, when the predetermined pixel region of the reflected infrared image data 21 is determined as the “correction target region” by the procedure using FIG. 5 and FIG. As shown in FIG. 7, an area where the “identification target area” shown in FIG. 7A and the “correction target area” shown in FIG. 7B overlap is the reflected visible light image data 22. It is determined as a “final correction target area”.

  In FIG. 7, the case where “identification target area” is specified has been described, but conversely, “identification non-target area” is specified and areas other than the specified “non-identification target area” are specified. May be set as “identification target area”. In addition, both “identification target area” and “non-identification target area” may be designated.

  Next, a case where the correction process according to the present embodiment is particularly effective will be described with reference to FIG. FIG. 8 is a diagram showing the arrangement of light receiving and emitting elements when transmitted light identification is used together. In addition, in the same figure, the side view of the conveyance path in which a banknote is conveyed is shown.

  As shown in the figure, the light receiving element 3 is provided on the upper surface of the conveyance path, and the light receiving / light emitting element 2 is provided on the lower surface of the conveyance path. The light receiving / light emitting element 2 receives reflected light of the light irradiated to the bill by the light receiving / light emitting element 2 itself. In addition, the light receiving element 3 receives the transmitted light transmitted through the bill by the light irradiated to the bill by the light receiving / light emitting element 2. The transmitted light received by the light receiving element 3 can also be used for bill recognition.

  Thus, when the light emitting / receiving elements are provided on the upper surface of the conveying path and the lower surface of the conveying path, the clearance provided between the upper surface of the conveying path and the lower surface of the conveying path is larger than when the light emitting / receiving elements are provided on one side of the conveying path. It is necessary to take. The reason is that when only the light receiving / light emitting element 2 is used, the clearance can be reduced by using a mechanism (roller or the like) that presses the bill to be conveyed against the light receiving / light emitting element 2.

  However, as shown in FIG. 8, when light emitting and receiving elements are arranged on the upper surface of the transport path and the lower surface of the transport path, it is difficult to attach a mechanism such as a roller. Therefore, the correction process according to the present embodiment is particularly useful when it is necessary to provide a predetermined clearance in the conveyance path.

  As described above, in this embodiment, the light emitting / receiving element irradiates the paper with light of at least two wavelengths of visible light and infrared light, and the visible light and infrared light are reflected by the paper sheet, respectively. Receives reflected visible light and reflected infrared light. And the correction | amendment process part which received light reception data comprised the paper sheet identification device so that the intensity distribution of reflected visible light may be corrected based on the intensity distribution of reflected infrared rays. Further, the paper sheet recognition apparatus is configured such that the identification processing unit performs the banknote identification process using the corrected reflected visible light intensity distribution.

  That is, highly accurate reflected visible light image data can be acquired by correcting the intensity distribution of reflected visible light using reflected infrared rays that are likely to cause an output level difference depending on the distance between the light source and the paper sheet. Therefore, even if the paper sheet is fluttered, it is possible to easily acquire highly accurate image data and identify the paper sheet.

  As described above, the paper sheet identification device according to the present invention is suitable for easily acquiring high-precision image data and identifying paper sheets even when the paper sheets are fluttered. Yes. Further, the present invention can also be applied to an apparatus for scanning paper sheets with folds and the like.

It is a figure which shows the characteristic of the paper sheet identification device which concerns on a present Example. It is a figure which shows the relationship between reflected infrared image data and reading distance. It is a figure which shows the structure of the paper sheet identification device which concerns on a present Example. It is a figure which shows the structure of reflected infrared image data and reflected visible light image data. It is a figure which shows a correction | amendment object area | region. It is a flowchart which shows the process sequence of a correction process. It is a figure which shows an identification object area | region. It is a figure which shows light emitting / receiving element arrangement | positioning in the case of using transmitted light identification together.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper sheet identification device 2 Light receiving / light emitting element 3 Light receiving element 10 Control part 11 Image input part 12 Correction process part 13 Identification process part 20 Storage part 21 Reflected infrared image data 22 Reflected visible light image data 23 Corrected reflected visible light image Data 24 Template data

Claims (4)

A paper sheet identification device for identifying the type of the paper sheet by irradiating light to the conveyed paper sheet,
A light irradiating means for irradiating the paper with at least two wavelengths of visible light and infrared light;
A light receiving means for receiving the reflected visible light and the reflected infrared light reflected by the paper sheets, respectively, the visible light and the infrared light;
And a correction unit that corrects the intensity distribution of the reflected visible light based on the intensity distribution of the reflected infrared ray. The correction means includes
The paper sheet identification apparatus according to claim 1, wherein the intensity distribution of the reflected visible light is corrected only for a region where the intensity of the reflected infrared light is equal to or greater than a predetermined threshold. The correction means includes
A correction amount at each position related to the intensity distribution of the reflected visible light is calculated based on the intensity of the reflected infrared light and the predetermined threshold, and the intensity distribution of the reflected visible light is corrected based on the correction amount. The paper sheet identification apparatus according to claim 1 or 2. An identification target area storing means for storing an identification target area designated for each paper sheet;
The correction means includes
The paper sheet identification apparatus according to claim 2 or 3, wherein the intensity distribution of the reflected visible light is corrected only for an area included in the identification target area.

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