Authenticity determination device and program

Abstract

To provide an authenticity determination device etc., capable of suitably making an authenticity determination in identifying a person.SOLUTION: An authenticity determination device 3 makes an authenticity determination on an ID card 10. The authenticity determination device 3 comprises: acquisition means 301 which acquires a visible light image and an infrared image of the ID card 10; and authenticity determination means 302 which finds, as a determination value, the number of pixels having the gray level in the visible light image and the infrared image among pixels in a plurality of inspection regions of the ID card 10 satisfying a predetermined standard for the inspection regions, and determines whether or not the inspection regions are correct from results of comparison of the determination value with a threshold so as to make the authenticity determination on the ID card 10 according to the determination result. Further, the plurality of inspection regions differ at least in the predetermined standard, or in relation between the comparison results and the propriety of the inspection regions.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a forgery determination device, its program, and the like.

Background Art

[0002] When opening an account or the like, it is common for the user to visit a financial institution and submit a personal identification card (ID card), and the financial institution performs face-to-face identification using the submitted personal identification card. In addition, Patent Document 1 describes that when issuing various media in a proof photo machine, personal identification is performed using a personal identification card. Thus, personal identification to prevent fraud is performed in various scenarios.

[0003] At this time, it is important to determine whether there is forgery, alteration, etc. in the personal identification card, or to determine the authenticity of the personal identification card. Patent Documents 1 and 2 describe techniques for determining the authenticity of a personal identification card from an image of the personal identification card, and it is possible to automatically determine the authenticity of the personal identification card based on the features and character information of the image of the personal identification card.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above is an example of using the features and character information of an image of a personal identification card for determination. However, as features of a regular personal identification card (ID card), printing is performed by a predetermined printing method for each area of the ticket surface, and it can also be mentioned that the ink used and the printing method are different for each area. Therefore, it is also possible to improve the accuracy of forgery determination by utilizing the differences in the ink used for each area and the like.

[0006] In recent years, identity verification has become increasingly stringent, and there is a growing demand for technologies that can reliably determine the authenticity of identification documents. Technologies that utilize the differences mentioned above are expected to contribute to improving the accuracy of such authenticity determination.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a genuineness determination device, etc., that can suitably determine the authenticity of an identity verification document. [Means for solving the problem]

[0008] The first invention for solving the aforementioned problems is a genuineness determination device for determining the authenticity of an identity document, comprising: acquisition means for acquiring a visible light image and an infrared image of the identity document; and genuineness determination means for determining, for each of a plurality of inspection areas of the identity document, the number of pixels within the inspection area whose density in the visible light image and the infrared image satisfies a predetermined standard as a discrimination value, determining whether the inspection area is genuine or not from the result of comparing the discrimination value with a threshold, and determining the authenticity of the identity document from the discrimination result, wherein at least one of the predetermined standard and the relationship between the comparison result and the authenticity of the inspection area differs among the plurality of inspection areas.

[0009] In this invention, a genuine identification document is manufactured by printing each area of ​​the document surface using a predetermined printing method, and the authenticity of the document is determined by utilizing the fact that the appearance of shading in these areas differs between visible light images and infrared images depending on the ink used. For example, areas printed with ink containing infrared-absorbing components such as carbon appear as dark areas (high-density areas) in both visible light and infrared images, while areas printed with ink that does not absorb infrared light appear as dark areas in visible light images and as light areas (low-density areas) in infrared images. Therefore, cases of forgery or alteration using ink with different infrared absorption characteristics than that used in genuine identification documents can be effectively detected. Furthermore, the accuracy of authenticity determination is improved by changing the criteria for each of the multiple inspection areas according to the ink used and determining whether the inspection area is from a genuine identification document.

[0010] Here, the grayscale in the visible light image refers to the grayscale of a predetermined color component of the visible light image, or the grayscale indicating the degree of brightness of each pixel in the visible light image. The authenticity determination means may also create a spectral image in which an image showing the grayscale of each color component of the visible light image and an image showing the degree of brightness of each pixel in the visible light image are represented by grayscale, and may use the grayscale of the pixels in the spectral image for the determination. In this case, it is also desirable that the spectral image used for the determination differs among the multiple inspection areas. In this way, by using spectral images corresponding to the color of the printed area to determine whether each inspection area is genuine or not, the accuracy of authenticity determination can be improved.

[0011] Preferably, the authenticity determination means creates a binary image by binarizing the grayscale of the spectral image and the infrared image, and determines whether the inspection area is authentic or not based on the pixel values ​​in the binary image. This reduces the processing burden when determining authenticity.

[0012] For example, the predetermined criteria may differ among multiple inspection areas, such that in one inspection area, the predetermined criterion is that the area appears as a dense area in both the spectral image and the infrared image, while in another inspection area, the predetermined criterion is that the area appears as a dense area in the spectral image and as a pale area in the infrared image. This allows for accurate determination of the authenticity of identification documents by distinguishing between genuine and counterfeit areas printed with inks having different infrared absorption properties.

[0013] For example, among multiple inspection areas, the predetermined criteria are the same, but the relationship between the comparison result and the correctness of the inspection area differs, and the predetermined criteria are that it appears as a dense area in the spectral image and as a pale area in the infrared image, and in one inspection area, the inspection area is considered correct when the discriminant value is less than or equal to the threshold, and in another inspection area, the inspection area is considered correct when the discriminant value is greater than or equal to the threshold. This allows for the detection of forgery or alteration of genuine identification documents using inks with different infrared absorption properties (inks that do not absorb infrared rays) in areas printed with inks containing infrared-absorbing components, and also allows for the detection of cases where areas printed with non-infrared-absorbing ink on genuine identification documents are lost during the forgery or alteration process.

[0014] It is also desirable that the authenticity determination means perform a dilation process on the binary image obtained by binarizing the grayscale of the infrared image, and use the dilated binary image for the determination. This makes it possible to suppress the decrease in judgment accuracy caused by the misalignment between visible light images and infrared images.

[0015] The second invention is a program for causing a computer to function as a genuine / fake determination device that determines the authenticity of an identity verification. The program includes an acquisition means for acquiring a visible light image and an infrared image of the identity verification, and for each of a plurality of inspection areas of the identity verification, determining, as a discrimination value, the number of pixels within the inspection area whose light and shade in the visible light image and the infrared image satisfy a predetermined criterion, determining whether the inspection area is genuine or not from the comparison result between the discrimination value and a threshold value, and performing a genuine / fake determination of the identity verification from the determination result. Among the plurality of inspection areas, at least the predetermined criterion is different, or the relationship between the comparison result and the authenticity of the inspection area is different. The second invention is a program for the genuine / fake determination device of the first invention.

Advantages of the Invention

[0016] According to the present invention, it is possible to provide a genuine / fake determination device and the like that can suitably perform the genuine / fake determination of an identity verification.

Brief Description of the Drawings

[0017] [Figure 1] A diagram showing the genuine / fake determination system 1. [Figure 2] A diagram showing the hardware configuration of the genuine / fake determination device 3. [Figure 3] A diagram showing an example of the ID card 10. [Figure 4] A diagram showing the functions of the genuine / fake determination device 3. [Figure 5] A flowchart showing an outline of the genuine / fake determination method. [Figure 6] A flowchart showing the procedure of the genuine / fake determination. [Figure 7] A diagram showing binary images 20 and 30 of a spectral image and an infrared image. [Figure 8] An example of the inspection area 11. [Figure 9] A diagram for explaining the method of determining the authenticity of the inspection area 11 (mode 0). [Figure 10] A diagram for explaining the method of determining the authenticity of the inspection area 11 (mode 1). [Figure 11] This diagram illustrates the method for determining whether the inspection area 11 is correct or incorrect (mode 2). [Figure 12] A diagram explaining setting information 40. [Modes for carrying out the invention]

[0018] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0019] (1. Authenticity Determination System 1) Figure 1 shows a counterfeit detection system 1 having a counterfeit detection device 3 according to an embodiment of the present invention. As shown in Figure 1, the counterfeit detection system 1 is configured by connecting a reader 2 and a counterfeit detection device 3 so that they can communicate with each other by wire or wireless. In the counterfeit detection system 1, an image of the ID card 10 is transmitted from the reader 2 to the counterfeit detection device 3, and the counterfeit detection device 3 performs a counterfeit detection of the ID card 10 from the image.

[0020] The reader 2 photographs the ID card 10 and acquires an image of it. In particular, in this embodiment, the reader 2 is equipped with a visible light camera and visible light illumination, and an infrared camera and infrared illumination.

[0021] When using a visible light camera, the visible light emitted from the visible light illumination and reflected from the ID card 10 is received by the visible light camera. When using an infrared camera, the infrared light emitted from the infrared illumination and reflected from the ID card 10 is received by the infrared camera. Hereinafter, the image of the ID card 10 captured by the visible light camera will be referred to as the visible light image, and the image of the ID card 10 captured by the infrared camera will be referred to as the infrared image.

[0022] Figure 2 shows the hardware configuration of the authenticity determination device 3. The authenticity determination device 3 can be implemented by a computer configured by connecting a control unit 31, a storage unit 32, a communication unit 33, a display unit 34, etc., via a bus or the like. However, it is not limited to this, and various configurations can be adopted as appropriate.

[0023] The control unit 31 consists of a CPU, ROM, RAM, etc. The CPU calls and executes programs related to the processing of the authenticity determination device 3, which are stored in storage media such as the memory unit 32 and ROM, into a work area on the RAM. ROM is a non-volatile memory that permanently holds programs and data such as the boot program and BIOS. RAM is a volatile memory that temporarily holds programs and data loaded from the memory unit 32, ROM, etc., and also has a work area used by the control unit 31 to perform various processes.

[0024] The memory unit 32 is a hard disk drive, solid-state drive, flash memory, etc., and stores the program that the authenticity determination device 3 executes during the processing described later, the data necessary for program execution, the OS, etc.

[0025] The communication unit 33 is a communication interface that mediates communication with the reader 2. The display unit 34 is a liquid crystal display or the like, and displays various information related to determining the authenticity of the ID card 10.

[0026] (2. ID card 10) In this embodiment, ID card 10 is an identification document that is subject to authenticity verification. An identification document is a medium used for administrative procedures and identity verification by various government agencies, financial institutions, mobile phone carriers, etc., and is, for example, a driver's license. However, ID card 10 is not limited to this and may also be a My Number Card, residence card, special permanent resident certificate, etc.

[0027] Figure 3 is a schematic diagram of ID card 10 (driver's license), illustrating a schematic example of the card's surface. ID card 10 is printed on a roughly rectangular card base with the cardholder's name 101, date of birth 102, address 103, date of issuance 104, expiration date 105, issuance number 106, issuing authority 107, seal 108, and photograph 109 printed on it.

[0028] The name 101, date of birth 102, address 103, date of issuance 104, expiration date 105, issuance number 106, and facial photograph 109 are on-demand information that differs for each individual ID card 10. This on-demand information is formed by printing it at a fixed position on the card substrate using a thermal transfer printing method with a thermal head. The text other than the facial photograph 109 is printed using a fusion thermal transfer method, and the facial photograph 109 is printed using a sublimation thermal transfer method.

[0029] On the other hand, the characters such as "Name," "Address," "Issued," and "Number" that indicate the fields for the name 101, address 103, date of issuance 104, and issuance number 106, as well as the issuer 107, seal 108, the words "Driver's License" 110, and ruled lines, are used in common on each ID card 10. These characters and ruled lines are formed in advance at fixed positions on the card substrate using a printing method such as offset printing or letterpress printing before the on-demand information is printed, and are called pre-printed areas.

[0030] The ID card 10 is manufactured by printing the aforementioned on-demand information onto a card substrate that has a pre-printed portion formed in advance. The configuration of the on-demand information and the pre-printed portion varies depending on the type of ID card 10, such as a driver's license, My Number card, residence card, or special permanent resident certificate.

[0031] (3. Authenticity Determination Device 3 Functions) Figure 4 is a block diagram showing the functions of the authenticity determination device 3. The authenticity determination device 3 includes an acquisition means 301, an authenticity determination means 302, etc.

[0032] The acquisition means 301 involves the control unit 31 of the authenticity determination device 3 receiving and acquiring the visible light image and infrared image of the ID card 10 from the reader 2 via the communication unit 33.

[0033] The authenticity determination means 302 is a mechanism in which the control unit 31 of the authenticity determination device 3 uses the visible light image and infrared image of the ID card 10 acquired from the reader 2 to determine the authenticity of the ID card 10.

[0034] (4. Outline of methods for determining authenticity) Figure 5 is a flowchart illustrating the authenticity determination method performed by the authenticity determination system 1. S1 to S2 in Figure 5 are processes executed by the control unit (not shown) of the reading device 2, which controls each part of the reading device 2, and S3 to S5 are processes executed by the control unit 31 of the authenticity determination device 3, which controls each part of the authenticity determination device 3.

[0035] In this embodiment, first the user places the ID card 10 in a predetermined position on the reader 2, and the reader 2 photographs the ID card 10 using a visible light camera and an infrared camera, respectively, in response to the user's operation (S1).

[0036] The reader 2 transmits the visible light image and infrared image obtained by photographing the ID card 10 to the authenticity determination device 3 (S2). The authenticity determination device 3 receives the visible light image and infrared image of the ID card 10 (S3) and uses the visible light image and infrared image to determine the authenticity of the ID card 10 (S4). Both the visible light image and the infrared image are assumed to be images in which the color of each pixel is represented by the gradation values ​​of the R (red), G (green), and B (blue) components. In the infrared image, the R, G, and B gradation values ​​of each pixel are approximately the same. However, the infrared image obtained by photographing the ID card 10 with an infrared camera may be a grayscale image in which the degree of brightness of each pixel is represented by gradation values, in which case the grayscale conversion in S105 described below is unnecessary.

[0037] The authenticity determination device 3 displays the authenticity determination result of the ID card 10 on the display unit 34 (S5) and terminates the process. The person in charge who sees the display unit 34 can then take appropriate action. The authenticity determination device 3 may also display instructions corresponding to the authenticity determination result of the ID card 10 on the display unit 34, prompting the person involved to take appropriate action.

[0038] In this embodiment, in S4, a genuine ID card 10 is manufactured by printing each area of ​​the card surface using a predetermined printing method, and authenticity is determined by utilizing the fact that the appearance of shading in these areas differs between visible light images and infrared images depending on the ink used. The details of the authenticity determination method will be described below.

[0039] (5. Authenticity verification of ID card 10) Figure 6 is a flowchart showing the procedure for determining the authenticity of ID card 10 in S4.

[0040] In this embodiment, in S4, the visible light image and infrared image received in S3 are first resized to a predetermined size (S101). This speeds up subsequent processing. The above size is the same for the visible light image and the infrared image, and is not limited to, for example, being reduced to about half the original size of the visible light image and infrared image.

[0041] Next, the authenticity determination device 3 masks the face photograph 109 in the resized visible light image and infrared image (S102). This process is to prevent the grayscale values ​​of the pixels in the face photograph 109 from affecting the subsequent binarization process. The masking process is performed by replacing the grayscale values ​​of the pixels in the face photograph 109 with specific mask values.

[0042] Next, the authenticity determination device 3 creates a spectral image from the visible light image after masking (S103). In this process, a spectral image is created in which the grayscale values ​​of the R, G, and B components of each pixel of the visible light image are used as the grayscale values ​​of each pixel. Hereinafter, the image with the grayscale value of the B component will be called the B image, the image with the grayscale value of the G component will be called the G image, and the image with the grayscale value of the R component will be called the R image. The B image, G image, and R image are spectral images that show the intensity of the R, G, and B components, respectively.

[0043] In S103, a spectral image is created, in which the largest of the R, G, and B component tonal values ​​of each pixel in the visible light image is used as the tonal value of each pixel. This image shows the degree of brightness of each pixel in the visible light image as grayscale, and is hereafter referred to as the V (brightness) image. For example, if the tonal values ​​of the R, G, and B components of a certain pixel in the visible light image are (R, G, B) = (10, 20, 30), then the tonal value of the corresponding pixel in the V image will be 30.

[0044] As a result, in subsequent processing, the grayscale of the visible light image will be represented by the grayscale of each color component of the visible light image, or by the grayscale indicating the degree of brightness of each pixel in the visible light image.

[0045] The authenticity determination device 3 binarizes the spectral images created in S103 (S104). The method of binarization is not particularly limited, but in this embodiment, binarization is performed using the Otsu method. The Otsu method is a method that automatically determines the threshold value for binarization from the grayscale value histogram of the entire image, and is known in the field of image processing. However, it is also possible to perform binarization using a predetermined threshold value.

[0046] Figure 7(a) shows examples of binary images 20 of spectral images (B image, G image, R image, V image). These binary images 20 represent the high-density areas (dark areas) in the spectral image with black pixels and the low-density areas (light areas) with white pixels, so the printed areas are basically black pixels (dark areas).

[0047] However, in the binary images 30 of the B, G, and R images, the parts printed in these colors (for example, the parts printed in red in the R image) do not appear as black pixels, but as white pixels (light areas). On the other hand, the parts printed in colors close to the complementary color of these colors (for example, the parts printed in red in the B image) appear as black pixels.

[0048] The authenticity determination device 3 also performs grayscale conversion on the infrared image after masking, followed by binarization (S105). Grayscale conversion is performed because the R, G, and B component tonal values ​​of pixels in the infrared image may differ from each other, but as mentioned above, it can be omitted if the infrared image is a grayscale image. Grayscale conversion can be performed using known methods.

[0049] Unlike the previous method, the binarization of infrared images is performed using a predetermined threshold. It is desirable to set an appropriate threshold value depending on the type of ID card 10. However, as before, binarization may also be performed using Otsu's method. Figure 7(b) is an example of a binarized image 30 of an infrared image. In an infrared image, areas printed with ink containing infrared-absorbing components become high-density areas (dark areas), and in the binarized image 30, these areas appear as black pixels.

[0050] Next, the authenticity determination device 3 performs a dense area dilation process on the binary image 30 of the infrared image (S106). Dense dilation is also a known technique in the field of image processing. For example, if there are black pixels within a certain size range, all pixels within that range are converted to black pixels, thereby dilating the dense areas. This allows the process in S108, described later, to be performed without problems even if there is a slight positional shift between the spectral image and the infrared image. Figure 7(c) shows an example of the binary image 30 after dilation dilation.

[0051] After preprocessing the spectral image and infrared image respectively to create binary images 20 and 30, the authenticity determination device 3 extracts the inspection area from the binary images 20 and 30 of the spectral and infrared images (S107). The inspection area is predetermined for each type of ID card 10, and a portion of it is shown on the visible light image of the ID card 10 in Figure 8. As shown in Figure 8, in this embodiment, multiple inspection areas 11 are defined on the surface of the ID card 10, and these inspection areas 11 are extracted from both the binary images 20 and 30 of the spectral and infrared images. The inspection area 11 is mainly set in the text portion of the surface of the ID card 10.

[0052] The authenticity determination device 3 then determines whether the inspection area 11 is genuine or not (whether the inspection area 11 belongs to a genuine ID card 10) based on the pixel values ​​of the binary images 20 and 30 (S108).

[0053] In S108, based on the pixel values ​​of binary images 20 and 30, the number of pixels within the inspection area 11 whose grayscale in the spectral image and infrared image meets a predetermined standard is determined as a discrimination value, and the pass / fail status of the inspection area 11 is determined from the comparison result between the discrimination value and the threshold. In particular, in this embodiment, the predetermined standard described above, the relationship between the comparison result and the pass / fail status of the inspection area 11, etc., differ for each inspection area 11. More specifically, it mainly differs depending on whether the inspection area 11 is printed with ink containing an infrared absorbing component or with ink that does not. The differences in the method of determining the pass / fail status of the inspection area 11 (referred to as "mode") will be explained below.

[0054] <Mode 0; when the inspection area 11 is printed with ink containing infrared light-absorbing components> If the inspection area 11 is the part of the regular ID card 10 that is printed with ink containing an infrared-absorbing component, then the printed area will appear as a dark area in both the spectral image (V image in this example) and the infrared image, as shown in Figure 9(a), and will appear as black pixels in these binary images 20 and 30.

[0055] On the other hand, Figure 9(b) shows the ID card 10 with writing 12 done in the inspection area 11 using ink that does not absorb infrared light. In this case, the part with writing 12 appears as a dark area in the spectral image and a light area in the infrared image, appearing as a black pixel in the binary image 20 of the spectral image, but appearing as a white pixel in the binary image 30 of the infrared image.

[0056] Figure 9(c) shows pixels that appear black in the spectral binary image 20 and white in the infrared binary image 30 as white pixels, and all other pixels as black pixels. The authenticity determination device 3, in order to detect alterations such as those caused by writing 12 with inks having different infrared absorption characteristics as described above, counts the number of pixels that appear black in the spectral binary image 20 and white in the infrared binary image 30 (white pixels in Figure 9(c)) in the inspection area 11 cut out from the spectral binary image 20 and the infrared binary image 30, and uses this count as the discrimination value. The discrimination value is then compared with a threshold, and if the discrimination value is less than or equal to the threshold, the inspection area 11 is determined to be genuine; if the discrimination value exceeds the threshold, the inspection area 11 is determined to be not genuine.

[0057] In this case, the predetermined criteria mentioned above is "that the area appears dark in the spectral image and light in the infrared image (that the pixel appears black in the binary image 20 and white in the binary image 30)," and the relationship between the comparison result and the correctness of the inspection area 11 is "that the inspection area 11 is correct if the discriminant value is below the threshold."

[0058] <Mode 1; In the inspection area 11, there is a part printed with ink that does not absorb infrared light, and that part disappears due to forgery, alteration, etc.> Some parts of ID card 10 are printed with ink that does not absorb infrared rays, and in counterfeit or altered ID cards 10, these parts are sometimes missing.

[0059] For example, Figure 10(a) shows the inspection area 11 containing the issuance number 106 of the ID card 10 for the spectral image (image B in this example) and the binary images 20 and 30 of the infrared image, respectively. In addition to the issuance number 106, the inspection area 11 also contains a shaded area 13 printed with red ink that does not absorb infrared light. This shaded area 13 appears as a dark area in the spectral image and a light area in the infrared image, appearing as a black pixel in the binary image 20 of the spectral image and as a white pixel in the binary image 30 of the infrared image.

[0060] On the other hand, Figure 10(b) shows the ID card 10 with the shaded area 13 removed from the inspection area 11. In this case, the area where the shaded area has been removed becomes a pale area in the spectral image and a white pixel in the binary image 20 of the spectral image.

[0061] Figure 10(c) shows pixels that appear black in the spectral binary image 20 and white in the infrared binary image 30 as white pixels, and all other pixels as black pixels. The authenticity determination device 3 detects cases where parts that should be printed with ink that does not absorb infrared light have disappeared during the process of forgery or alteration, etc. For the inspection area 11 cut out from the spectral binary image 20 and the infrared binary image 30, the device counts the number of pixels that appear black in the former binary image 20 and white in the latter binary image 30 (white pixels in Figure 10(c)), and uses this count as the discrimination value. The device then compares the discrimination value with a threshold value, and if the discrimination value is greater than or equal to the threshold value, the device determines that the area is genuine, and if the discrimination value is less than the threshold value, the device determines that the area is not genuine.

[0062] In this case, the predetermined criteria mentioned above is "that the area appears dark in the spectral image and light in the infrared image (that the pixel appears black in the binary image 20 and white in the binary image 30)," and the relationship between the comparison result and the correctness of the inspection area 11 is "that the inspection area 11 is correct if the discriminant value is equal to or greater than the threshold."

[0063] <Mode 2; When the inspection area 11 is printed with ink that does not absorb infrared light> If the inspection area 11 is a portion of the regular ID card 10 printed with ink that does not absorb infrared light, then, as shown in Figure 11(a), the printed portion will appear as a dark area in the spectral image (V image in this example), but as a light area in the infrared image, appearing as a black pixel in the binary image 20 of the spectral image and as a white pixel in the binary image 30 of the infrared image.

[0064] On the other hand, Figure 11(b) shows that in the inspection area 11 of the ID card 10, the portion that is printed with ink that does not absorb infrared light is printed with ink containing a component that absorbs infrared light. In this case, the printed portion 14 becomes a dark area in both the spectral image and the infrared image, and appears as a black pixel in both the binary image 20 of the spectral image and the binary image 30 of the infrared image.

[0065] Figure 11(c) shows pixels that are black in both the spectral binary image 20 and the infrared binary image 30 as white pixels, and all other pixels as black pixels. The authenticity determination device 3, in order to detect forgery or alteration caused by printing with inks that have different infrared absorption characteristics as described above, counts the number of pixels that are black in both binary images 20 and 30 (white pixels in Figure 11(c)) in the inspection area 11 cut out from the spectral binary image 20 and the infrared binary image 30, and uses this count as the discrimination value. Then, the discrimination value is compared with a threshold, and if the discrimination value is less than or equal to the threshold, the inspection area 11 is determined to be genuine, and if the discrimination value exceeds the threshold, the inspection area 11 is determined to be not genuine.

[0066] In this case, the predetermined criterion is "that the area is dense in the spectral image and infrared image (that the pixels are black in the binary images 20 and 30)," and the relationship between the comparison result and the correctness of the inspection area 11 is "that the inspection area 11 is correct if the discriminant value is below the threshold."

[0067] Thus, in S108, a predetermined discrimination method (modes 0 to 2 described above) is performed for each inspection area 11 according to the differences in the ink used, and it is determined whether or not the inspection area 11 extracted in S107 is positive.

[0068] The authenticity determination device 3 repeats the processes S107 to S108 until it has made the above determination for all inspection areas 11 (S109; No), and after determining whether all inspection areas 11 are true or false (S109; Yes), it makes an authenticity determination of the ID card 10 based on the determination results for each inspection area 11 (S110).

[0069] In this embodiment, the ID card 10 is considered true if all inspection areas 11 are determined to be positive, and false otherwise; however, it is not limited to this. For example, the ID card 10 can be considered true if the number of inspection areas 11 determined to be positive is equal to or greater than a predetermined number.

[0070] Furthermore, the processing in S107 to S108 can be performed by the authenticity determination device 3, which reads setting information from the storage unit 32 that defines the position and discrimination method of the inspection area 11 for each type of ID card 10, and performs the processing based on the setting information.

[0071] Figures 12(a) and (b) illustrate the setting information 40 for different types of ID cards 10. The setting information 40 in this embodiment includes data for the range of the inspection area 41, the spectral image 42 used for discrimination, the mode 43, and the threshold value 44 at the time of discrimination, and is determined for each type of ID card 10. The authenticity determination device 3 can read the setting information 40 according to the type of ID card 10 to be judged and execute the processes S107 to S108.

[0072] The inspection area range 41 is defined in S107 as the range from which the inspection area 11 is extracted from the binary images 20 and 30 of the spectral and infrared images. For example, the upper left and lower right corners of the rectangular inspection area 11 are specified on the orthogonal two axes.

[0073] The spectral image 42 used for discrimination is specified in the discrimination procedure described in modes 0 to 2 above, indicating which spectral image to use. The inspection area 11 is mainly set to the text portion, and the spectral image should basically be the V image. However, exceptionally, for parts printed in color, it is desirable to use a color close to the complementary color of the printed color in order to make those parts appear as dark areas in the spectral image. For example, for inspection area 11 that includes parts printed in red, such as the hatched area 13 above, it is good to select the B image. Thus, in this embodiment, the spectral image used for discrimination may also differ between inspection areas 11.

[0074] Mode 43 determines which of the modes 0 to 2 described above will be implemented, and in this embodiment, as described above, different modes are set for multiple inspection areas 11 within the ID card 10. The threshold 44 is a threshold that is compared with the discrimination value described in modes 0 to 2, and this also differs depending on the inspection area 11.

[0075] Furthermore, in this embodiment, as shown in the dashed frame of the setting information 40 in Figures 12(a) and (b), for the inspection area 11 where discrimination by mode 1 has been performed, discrimination by mode 0 or mode 2 is also performed simultaneously.

[0076] This is because, for example, in the example of Mode 1 explained in Figure 10, the issuance number 106 itself, excluding the shaded area 13, is printed with ink containing infrared-absorbing components, making it useful to perform discrimination using Mode 0 separately. Furthermore, in the example of Mode 2 explained in Figure 11, it is useful not only to determine whether or not the portion printed with ink containing infrared-absorbing components exists in the inspection area 11, but also to perform discrimination using Mode 1 to detect whether the portion printed with ink that does not absorb infrared rays has disappeared during the process of forgery, alteration, etc.

[0077] As explained above, in this embodiment, a genuine ID card 10 is manufactured by printing each area of ​​the card surface using a predetermined printing method, and authenticity is determined by utilizing the fact that the appearance of shading in these areas differs between visible light images and infrared images depending on the ink used. For example, areas printed with ink containing infrared-absorbing components such as carbon appear as dark areas (high-density areas) in both visible light images and infrared images, while areas printed with ink that does not absorb infrared light appear as dark areas in visible light images and as light areas (low-density areas) in infrared images.

[0078] Therefore, in this embodiment, as shown in Figures 9 to 11, it is possible to suitably detect cases in which counterfeit or altered ID cards are made using ink with different infrared absorption characteristics than the ink used in the genuine ID card 10, or cases in which parts that should originally be printed with ink that does not absorb infrared rays have disappeared during the counterfeiting or alteration process. Furthermore, by changing the criteria, etc., for each of the multiple inspection areas 11 according to the ink used, the accuracy of authenticity determination is improved.

[0079] Furthermore, in this embodiment, the processing burden when determining authenticity can be reduced by performing the above discrimination based on the values ​​of the binary images 20 and 30. However, it is also possible to use a multi-level image and perform the above discrimination based on the level of grayscale values.

[0080] Furthermore, in this embodiment, by determining the validity of the inspection area 11 using the modes 0 and 2 described above, it is possible to determine the validity of multiple inspection areas 11 printed on a genuine ID card 10 using inks with different infrared absorption characteristics, thereby enabling accurate determination of the authenticity of the ID card 10.

[0081] Furthermore, in this embodiment, by determining the validity of the inspection area 11 using Mode 0 and Mode 1, it is possible to detect counterfeiting, alteration, etc., of the portion of the genuine ID card 10 that is printed using ink containing an infrared-absorbing component, using ink with different infrared absorption characteristics (ink that does not absorb infrared rays), and it is possible to detect cases in which the portion of the genuine ID card 10 printed with ink that does not absorb infrared rays disappears during the process of counterfeiting, alteration, etc.

[0082] Furthermore, in this embodiment, the aforementioned dilation process is performed on the binary image 30 of the infrared image, and the dilated binary image is used to determine whether the inspection area 11 is correct or incorrect, thereby suppressing a decrease in judgment accuracy due to the misalignment between the visible light image and the infrared image.

[0083] Furthermore, in this embodiment, the accuracy of authenticity determination can be improved by using spectral images corresponding to the color of the printed portion to determine whether each inspection area 11 is correct or incorrect.

[0084] However, the present invention is not limited to the embodiments described above. For example, in this embodiment, B, G, R, and V images are created as spectral images in S103 (see Figure 6), but depending on the type of ID card 10, some spectral images may not be used. In S104, instead of binarizing all spectral images, only the spectral images to be used may be selected and binarized. This can speed up the processing.

[0085] Furthermore, in this embodiment, in S104, the threshold for binarization is determined from the grayscale value histogram of the entire image using Otsu's method. However, for example, in the field for the expiration date 105 of a driver's license, there is a high-density background color. If the threshold for binarization is determined from the grayscale value histogram of the entire image, there are cases where the expiration date 105 does not appear due to the density of the background color (both the background color and the expiration date 105 become black pixels). Therefore, in order to make such characters on a high-density background color visible during binarization, it is also possible to extract the inspection region 11 having characters on a high-density background color from the spectral image, and then apply Otsu's method only to that inspection region 11 to perform binarization.

[0086] Furthermore, the purpose of authenticity determination is not particularly limited and can be applied to identity verification when opening an account at a financial institution, when contracting for a mobile device, and during procedures at various government agencies. The present invention can also be applied to identity verification when making various applications or issuing media at photo booths.

[0087] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea disclosed herein, and these will naturally also fall within the technical scope of the present invention. [Explanation of symbols]

[0088] 1: Authenticity Verification System 2: Reader 3: Authenticity verification device 10: ID card 20: Binary image of the spectral image 30: Binary image of an infrared image 40: Configuration Information 301: Acquisition method 302: Means for determining authenticity

Claims

1. A device for determining the authenticity of an identification document, An acquisition means for acquiring visible light images and infrared images of the aforementioned identification document, Authenticity determination means that, for each of the multiple inspection areas of the aforementioned identification document, determines the number of pixels within the inspection area whose density in the visible light image and the infrared image satisfies a predetermined standard as a discrimination value, determines whether the inspection area is genuine or not based on the comparison result between the discrimination value and a threshold, and determines the authenticity of the identification document based on the determination result, Equipped with, Authenticity determination device characterized in that, among a plurality of inspection areas, at least one of the following differs: the predetermined criterion and the relationship between the comparison result and the correctness of the inspection area.

2. The density in the visible light image is the density of a predetermined color component of the visible light image, or the degree of brightness of each pixel in the visible light image. The aforementioned authenticity determination means is The authenticity determination device according to claim 1, characterized in that it creates a spectral image which is an image showing the intensity of each color component of the visible light image, and an image which shows the degree of brightness of each pixel of the visible light image as intensity, and uses the intensity of the pixels of the spectral image for the determination.

3. The authenticity determination device according to claim 2, characterized in that the spectral image used for the determination differs among the plurality of inspection regions.

4. The aforementioned authenticity determination means is The authenticity determination device according to claim 2, characterized in that a binary image is created by binarizing the grayscale of the spectral image and the infrared image, and the authenticity of the inspection area is determined based on the pixel values ​​in the binary image.

5. The predetermined criteria differ among the multiple inspection areas. In one of the inspection areas, the predetermined criterion is that it appears as a dense area in both the spectral image and the infrared image. The authenticity determination device according to claim 4, characterized in that, in another inspection area, the predetermined standard appears as a dense area in the spectral image and as a pale area in the infrared image.

6. Among the multiple inspection areas, the predetermined criteria are the same, but the relationship between the comparison result and the correctness of the inspection area differs. The prescribed criteria are that the area appears as a dark area in the spectral image and as a light area in the infrared image. In one of the aforementioned test areas, the test area is considered positive when the discriminant value is less than or equal to the threshold. In another of the aforementioned test areas, the test area is considered positive when the discriminant value is equal to or greater than the threshold. The authenticity determination device according to feature 4.

7. The authenticity determination device according to claim 5 or 6, characterized in that the authenticity determination means performs a dilation process on the binary image obtained by binarizing the grayscale of the infrared image, and uses the dilated binary image for the determination.

8. Computers, A device for determining the authenticity of an identification document, An acquisition means for acquiring visible light images and infrared images of the aforementioned identification document, Authenticity determination means that, for each of the multiple inspection areas of the aforementioned identification document, determines the number of pixels within the inspection area whose density in the visible light image and the infrared image satisfies a predetermined standard as a discrimination value, determines whether the inspection area is genuine or not based on the comparison result between the discrimination value and a threshold, and determines the authenticity of the identification document based on the determination result, Equipped with, A program for functioning as a genuine / counterfeit determination device, characterized in that, among a plurality of inspection areas, at least one of the following differs: the predetermined criterion or the relationship between the comparison result and the correctness of the inspection area.

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