Authenticity determination device and program

Abstract

To provide an authenticity determination device that can suitably determine authenticity of an identification card.SOLUTION: An authenticity determination device 3 is to determine authenticity of an ID card by using a photographed image of the ID card received from a user terminal 5. The authenticity determination device 3 has authenticity determination means 302 that determines the authenticity of the ID card based on spatial frequency characteristics of a predetermined part of the ID card. The authenticity determination means 302 takes the predetermined part as a face image, creates a Fourier-transformed image of an evaluation object for the face image, determines an evaluation value related to a difference between the Fourier-transformed image of the evaluation object and an original Fourier-transformed image, and determines authenticity on the basis of the evaluation value.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an authenticity determination device and a program therefor. [Background technology]

[0002] When opening an account at a financial institution, identification is required using an ID card (personal identification) such as a driver's license, but there has been an increase in cases where ID cards are forged or altered in order to open an account under the guise of another person for criminal purposes such as special fraud.

[0003] At typical financial institutions, users go to the institution to submit their ID card, and the financial institution then uses the submitted ID card to verify the user's identity in person. In this case, the ID card can be carefully observed, and any anomalies can be detected by touch alone.

[0004] Furthermore, Patent Documents 1 and 2 describe an authenticity determination device that determines the authenticity of an ID card from the image obtained by reading the face of the ID card with a reading device such as a scanner, and it is also possible to determine the authenticity of an ID card by reading a submitted ID card with a reading device such as a scanner. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-34535 [Patent Document 2] Japanese Patent Application Publication No. 2019-117549 Summary of the Invention [Problem to be solved by the invention]

[0006] Recently, online financial institutions such as online banks have become common. Some of these financial institutions verify identity by taking a photo of the face of an ID card with a camera on a smartphone or other device and sending the image to the financial institution.

[0007] In this case, identity verification is performed only by image rather than face-to-face, so a method for detecting counterfeits is desired. However, it is difficult to detect counterfeits from photographs of ID cards, which has been an issue when applying online.

[0008] The present invention has been made in view of the above problems, and has as its object to provide an authenticity determination device and the like that can suitably determine the authenticity of an identification card. [Means for solving the problem]

[0009] The first invention for solving the above-mentioned problems is: The facial image is printed using a specific printing method and resolution on a specific model of printer. A device for determining the authenticity of an identification card, comprising: a photograph of the identification card; a grayscale image obtained by converting the photograph of the identification card into a grayscale image; Facial image The authenticity of the identification card is determined based on the spatial frequency characteristics of , based on the difference between a Fourier transform image showing the spatial frequency characteristics of the facial image of the identification card and a positive Fourier transform image showing the spatial frequency characteristics of the facial image of a positive identification card in which the facial image is printed by the specific model of printer using the specific printing method and printing resolution. The authenticity determination device is characterized by having an authenticity determination means for performing the above-mentioned authentication. A second invention is an apparatus for determining the authenticity of an identification card, which has an authenticity determination means that uses a photographed image of the identification card to determine the authenticity of the identification card based on the spatial frequency characteristics of a specified part of the identification card, wherein the authenticity determination means creates a Fourier transform image of the specified part, determines an evaluation value regarding the difference between the Fourier transform image and a positive Fourier transform image as the Fourier transform image to be evaluated, and determines the authenticity based on the evaluation value, wherein the evaluation value is determined using the distance between the position of a bright point in a positive Fourier transform image in the Fourier transform image to be evaluated and the position with the highest brightness in an inspection range that includes the position of the bright point in the Fourier transform image to be evaluated.

[0010] The spatial frequency characteristics of a predetermined portion of an identification card differ depending on the printing method, printing resolution, etc. of that portion. Therefore, by performing an authenticity determination based on the spatial frequency characteristics of that portion from a photographed image of the identification card, it is possible to suitably distinguish between a genuine identification card in which that portion is printed using a specific printing method, printing resolution, etc., and an inauthentic identification card in which that portion is printed using a different printing method, printing resolution, etc.

[0011] The predetermined portion is, for example, a face image. A facial image has a relatively large area where there is little color change, and is therefore suitable for authenticity determination based on spatial frequency characteristics.

[0012] The second invention As described above, a Fourier transform image showing the spatial frequency characteristics of a specific portion of the identification card to be subjected to authenticity determination is created, an evaluation value relating to the difference with the positive Fourier transform image is calculated, and the evaluation value can be used to suitably determine the authenticity of the identification card.

[0013] Also The evaluation value can be calculated by using a bright spot that appears as a feature of a positive Fourier transform image and the distance between the position of the bright spot in the Fourier transform image of the evaluation target (the position where the bright spot should appear) and a position of high brightness that appears in the inspection range that includes the position of the bright spot. If this distance is small, the Fourier transform image of the evaluation target is similar to the positive Fourier transform image, and the authenticity of the identification card can be said to be high.

[0014] It is also preferable that the evaluation value be calculated using the distance and a coefficient corresponding to the luminance at the position with the highest luminance in the inspection range of the Fourier transform image to be evaluated. The brightness of the above-mentioned position of the Fourier transform image of the object to be evaluated is also a factor that can determine the difference between the Fourier transform image of the object to be evaluated and the positive Fourier transform image, and by using a coefficient according to the brightness, it is possible to more accurately determine authenticity.

[0015] It is desirable that the authenticity determination device has a receiving means for receiving the captured image from a user terminal. This makes it possible to construct an authenticity determination system using a network in which an authenticity determination device determines the authenticity of a photographed image of an identification card sent from a user terminal.

[0016] A third invention is a computer comprising: The facial image is printed using a specific printing method and resolution on a specific model of printer. A device for determining the authenticity of an identification card, comprising: a photograph of the identification card; a grayscale image obtained by converting the photograph of the identification card into a grayscale image; Facial image The authenticity of the identification card is determined based on the spatial frequency characteristics of , based on the difference between a Fourier transform image showing the spatial frequency characteristics of the facial image of the identification card and a positive Fourier transform image showing the spatial frequency characteristics of the facial image of a positive identification card in which the facial image is printed by the specific model of printer using the specific printing method and printing resolution. The program is for causing the device to function as an authenticity determination device having an authenticity determination means for performing the above steps. A fourth invention is a program for causing a computer to function as an authenticity determination device for an identification card, which has an authenticity determination means that uses a photographed image of the identification card to determine the authenticity of the identification card based on the spatial frequency characteristics of a specified part of the identification card, wherein the authenticity determination means creates a Fourier transform image of the specified part, determines an evaluation value relating to the difference between the Fourier transform image and a positive Fourier transform image as the Fourier transform image to be evaluated, and determines the authenticity based on the evaluation value, wherein the evaluation value is determined using the distance between the position of a bright point in a positive Fourier transform image in the Fourier transform image to be evaluated and the position with the highest brightness in an inspection range that includes the position of the bright point in the Fourier transform image to be evaluated. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an authenticity determination device and the like that can suitably determine the authenticity of an identification card. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 shows an authenticity determination system 1. [Figure 2] FIG. 2 is a diagram showing the hardware configuration of the authenticity determination device 3. [Figure 3] FIG. 2 is a diagram showing the hardware configuration of a user terminal 5. [Figure 4] FIG. 2 is a diagram showing the functional configuration of an authenticity determination device 3. [Figure 5] 1 is a diagram showing an ID card 10. FIG. [Figure 6] 1A and 1B are diagrams illustrating printing on an ID card 10. [Figure 7] 1A and 1B are diagrams illustrating printing on an ID card 10. [Figure 8] An example of ink placement. [Figure 9] 10 is a flowchart showing an authenticity determination method. [Figure 10] An example of the ID card 10 photo capture screen. [Figure 11] 10 is a flowchart showing the procedure for determining authenticity. [Figure 12] FIG. 10 is a diagram illustrating an authenticity determination method. [Figure 13] FIG. 10 is a diagram illustrating an authenticity determination method. [Figure 14] FIG. 10 is a diagram illustrating an authenticity determination method. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0020] (1. Authenticity Determination System 1) 1 is a diagram showing an authenticity determination system 1 having an authenticity determination device 3 according to an embodiment of the present invention. The authenticity determination system 1 is configured by connecting the authenticity determination device 3 and a user terminal 5 via a network so that they can communicate with each other. In the authenticity determination system 1, a captured image of a user's ID card 10 is sent from the user terminal 5 to the authenticity determination device 3, and the authenticity determination device 3 determines the authenticity of the ID card 10 from the captured image.

[0021] 2 is a diagram showing the hardware configuration of the authenticity determination device 3. The authenticity determination device 3 can be realized by a computer configured by connecting a control unit 31, a storage unit 32, a communication unit 33, etc. via a bus or the like. However, the authenticity determination device 3 is not limited to this and various configurations can be used as appropriate, and it is also possible to realize the authenticity determination device 3 using multiple computers.

[0022] The control unit 31 is composed of a CPU, ROM, RAM, etc. The CPU loads programs related to the processing of the authenticity determination device 3 stored in storage media such as the memory unit 32 and ROM into a work area on the RAM and executes them. The ROM is a non-volatile memory that permanently stores programs such as the boot program and BIOS, as well as data. The RAM is a volatile memory that temporarily stores programs and data loaded from the memory unit 32, ROM, etc., and also has a work area that the control unit 31 uses to perform various processes.

[0023] The storage unit 32 is a hard disk drive, a solid state drive, a flash memory, or the like, and stores programs executed by the authenticity determination device 3 in the processes described below, data required for program execution, an OS, and the like.

[0024] The communication unit 33 is a communication interface that mediates communication via a network, and communicates with the user terminal 5 .

[0025] The user terminal 5 is a terminal carried by the user, which takes a picture of the ID card 10 and transmits the photographed image to the authenticity determination device 3. As the user terminal 5, for example, a mobile terminal such as a smartphone or a tablet terminal is used.

[0026] Fig. 3 is a diagram showing the hardware configuration of the user terminal 5. As shown in Fig. 3, the user terminal 5 is configured by connecting a control unit 51, a storage unit 52, a display unit 53, an input unit 54, a communication unit 55, a camera 56, an audio input / output unit 57, etc. via a bus or the like. However, the configuration is not limited to this, and various other configurations may be used as appropriate.

[0027] The control unit 51, the storage unit 52, and the communication unit 55 are substantially the same as the above-described control unit 31, the storage unit 32, and the communication unit 33. The display unit 53 has a display device such as a liquid crystal panel, and is provided with a touch panel as an input unit 54 for inputting information to the user terminal 5. The audio input / output unit 57 has a microphone and a speaker used for audio input and output.

[0028] Camera 56 is an area camera that includes an optical lens, an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor), an A / D (Analog / Digital) converter, etc. Camera 56 photoelectrically converts the subject image input through the optical lens using the imaging element to generate an analog image signal. The A / D converter then converts the analog image signal into digital image data.

[0029] 4 is a diagram showing the functional configuration of the authenticity determination device 3. The authenticity determination device 3 includes a receiving means 301, an authenticity determination means 302, and the like.

[0030] The receiving means 301 is a means by which the control unit 31 of the authenticity determination device 3 receives a photographed image of the ID card 10 from the user terminal 5 via the communication unit 33 .

[0031] The authenticity determining means 302 determines the authenticity of the ID card 10 by using the photographed image of the ID card 10 received by the control unit 31 of the authenticity determining device 3 from the user terminal 5. Details of this authenticity determination will be described later.

[0032] (2. ID Card 10) In this embodiment, the ID card 10 is an identification card that is the subject of authentication. An identification card is a medium used for identity verification by financial institutions, mobile phone carriers, various administrative agencies, etc., and examples of such cards include a residence card, a driver's license, a My Number card, and a special permanent resident card.

[0033] 5 is a diagram showing an overview of an ID card 10, and is a schematic illustration of an example of the face of the ID card 10. The ID card 10 is formed by printing the card holder's name 12, date of birth 13, address 14, and facial image 18, the date of issue 15 of the ID card 10, the issue number 16, the expiration date 17, etc. on a substantially rectangular card substrate.

[0034] As will be described later, in this embodiment, the authenticity of the ID card 10 is determined based on the spatial frequency characteristics of the facial image 18. This facial image 18 is printed at a predetermined position on the card substrate by a thermal transfer method using a thermal head. In particular, in this embodiment, the facial image 18 is printed by a melting type thermal transfer method.

[0035] (3. Thermal transfer printing method) Printing by the thermal transfer method is performed by a thermal transfer printer 100 shown in Figure 6(a). In the thermal transfer printer 100, a thermal transfer ribbon 200 wound around a supply reel 101 is unwound and transported in the transport direction of the ID card 10 shown by the arrow, while heat is applied to the thermal transfer ribbon 200 by a thermal head 110 along the way, transferring the transfer layer of the thermal transfer ribbon 200 onto the ID card 10. After transfer, the thermal transfer ribbon 200 is taken up by a take-up reel 102.

[0036] Figure 6(b) is an example of the transfer layer 202 of the thermal transfer ribbon 200, in which inks of various colors such as Y (yellow), M (magenta), C (cyan), and K (black) are arranged in surface sequence on the substrate of the thermal transfer ribbon 200.

[0037] As shown in Figure 7(a), the thermal head 110 applies heat to the thermal transfer ribbon 200 from heating elements 111 provided on its underside. As shown in Figure 7(b), multiple heating elements 111 are arranged side by side on the underside of the thermal head 110. The arrangement direction of the heating elements 111 is perpendicular to the transport direction of the ID card 10 in a plane and corresponds to the direction of the short side of the ID card 10.

[0038] In the melting type thermal transfer method, when the heating element 111 applies heat to area a of the transfer layer 202 in Figure 7(a), the ink in this area adheres to the ID card 10, and when the thermal transfer ribbon 200 is taken up by the take-up reel 102 and separated from the ID card 10, it peels off from the base material 201 of the thermal transfer ribbon 200. This transfers the ink in the transfer layer 202 onto the ID card 10. In areas not heated by the heating element 111, the ink in the transfer layer 202 is not transferred to the ID card 10.

[0039] While the ID card 10 is conveyed by the conveying rollers 103, the heating by the heating elements 111 is controlled on and off for each heating element 111, and ink of Y, M, C, etc. is transferred from the transfer layer 202, thereby printing the facial image 18. The facial image 18 is printed using the size of the heating element 111 as a unit dot.

[0040] In the thermal melt transfer method, intermediate colors are expressed using an area modulation type gradation, and the arrangement of ink of each color is determined by a dithering method. For example, FIG. 8 shows an example of the arrangement (dot pattern) of ink of a predetermined color A. The dot pattern in FIG. 8 is repeated up, down, left, and right, resulting in the arrangement of ink of the predetermined color A having specific spatial frequency characteristics. For example, in FIG. 8, ink of the predetermined color A appears at a constant period along the direction indicated by the arrow. In this embodiment, authenticity determination is performed based on the spatial frequency characteristics of the facial image 18 derived from such direction and period.

[0041] (4. Authenticity determination method) Fig. 9 is a flowchart showing the flow of the authenticity determination method executed by the authenticity determination system 1. S1 to S2 and S7 to S8 in Fig. 9 are processes executed by the control unit 51 of the user terminal 5 by controlling each unit of the user terminal 5, and S3 to S6 are processes executed by the control unit 31 of the authenticity determination device 3 by controlling each unit of the authenticity determination device 3.

[0042] In this embodiment, the user first operates the user terminal 5 to launch a dedicated application program pre-stored in the storage unit 52. The user terminal 5 then displays a menu screen (not shown) on the display unit 53, and activates the camera 56 in accordance with the user's selection on the menu screen to photograph the face of the ID card 10 (S1).

[0043] 10 shows an example of the screen for capturing the ID card 10. In this embodiment, when the camera is started, instructions are displayed on the display unit 53 of the user terminal 5 to prompt the user to place the ID card 10 within a predetermined frame 531, and then the ID card 10 is captured.

[0044] When the user terminal 5 photographs the ID card 10, it transmits the photographed image (JPEG image) to the authenticity determination device 3 (S2). When the authenticity determination device 3 receives the photographed image of the ID card 10 (S3), it determines the authenticity of the ID card 10 using the photographed image (S4).

[0045] The authenticity determination in this embodiment is carried out by utilizing the fact that the spatial frequency characteristics of the facial image 18 differ depending on the printing method, printing resolution, etc. of the facial image 18 on the ID card 10. The authenticity determination method will be described in detail later.

[0046] If the authenticity determination device 3 determines that the ID card 10 is not genuine (S5; NO), it transmits a message to the user terminal 5 indicating that the ID card 10 is not genuine (S6). When the user terminal 5 receives a message indicating that the ID card 10 is not genuine (S7), it displays this message on the display unit 53 (S8) and ends the process.

[0047] On the other hand, if the authenticity determination device 3 determines that the ID card 10 is authentic (S5; YES), it completes the authenticity determination process. For example, when the above authenticity determination is performed as identity verification when opening an account at a financial institution on the Internet, after the authenticity determination process, user information (such as name and date of birth) on the face of the ID card 10 can be obtained from a photographed image of the ID card 10 as information required for opening the account, and the user information can be registered and stored in the memory unit 52.

[0048] (5. Authentication based on spatial frequency characteristics of facial images 18) As described above, in this embodiment, the authenticity determination in S4 (see FIG. 9) is performed by utilizing the fact that the spatial frequency characteristics of the face image 18 on the ID card 10 differ depending on the printing method, printing resolution, and the like.

[0049] That is, printing methods include the fusion type thermal transfer method, as well as the inkjet method, laser method, and dye sublimation type thermal transfer method. However, since the spatial frequency characteristics described above change depending on the printing method, it is possible to distinguish between a genuine ID card 10 on which the facial image 18 is printed by the fusion type thermal transfer method and a fake ID card 10 on which the facial image 18 is printed by another printing method.

[0050] Furthermore, the spatial frequency characteristics also change depending on the printing resolution, so that even if the ID cards 10 are printed using the same printing method, it is possible to distinguish between a genuine ID card 10 on which the facial image 18 is printed at a specific resolution and a fake ID card 10 on which the facial image 18 is printed at a different resolution.In addition, since the spatial frequency characteristics also change depending on the model of the printing machine, it is possible to distinguish between a genuine ID card 10 on which the facial image 18 is printed using a specific model of printing machine and a fake ID card 10 on which the facial image 18 is printed using a different model of printing machine, even if the ID cards 10 are printed using the same printing method and printing resolution.

[0051] 11 is a flowchart showing the procedure for authenticity determination in S4. In this embodiment, in S4, the resolution (dpi) of the captured image of the ID card 10 is first converted to a resolution required for frequency analysis (S41). The converted resolution is smaller than the resolution of the captured image, but both resolutions are values such that one dot of the facial image 18 when printed is equal to or larger than one pixel in the image.

[0052] In this embodiment, the captured image of the ID card 10 is then converted into a grayscale image (S42), and a facial image 18 is extracted from the captured image (S43). Then, as shown in FIG. 12(a), an image Im of a partial region (referred to as a region image) to be subjected to frequency analysis is cut out from the facial image 18 (S44). It is desirable that the region image Im has little color variation within the region, and in this embodiment, it is a skin-colored region of the facial image 18. Note that, as will be described later in this embodiment, a fast Fourier transform is performed as the frequency analysis, so it is desirable that the vertical and horizontal dimensions of the region image Im be a power of two.

[0053] Next, the authenticity determination device 3 performs a fast Fourier transform, which is a known frequency analysis method, on the luminance information of the regional image Im (S45).

[0054] 12(b) is an example of a Fourier transform image 210 obtained as a result of analysis by fast Fourier transform. The Fourier transform image 210 represents the spatial frequency characteristics of the region image Im, and as shown in the right diagram, the distance b of point p in the image 210 from the origin O represents the spatial frequency value, the direction of point p relative to the origin O (for convenience, represented by the angle θ relative to a reference line passing through the origin O) represents the direction in which a luminance change occurs at that spatial frequency, and the brightness (whiteness) of point p represents the power (square of the amplitude) of the luminance change at that spatial frequency.

[0055] Figure 13 shows examples of Fourier transform images created in the same way using the steps described in S41 to S45 for each of the following: (a) facial image 18 printed using a fusion thermal transfer method; (b) facial image 18 printed using a fusion thermal transfer method at a resolution different from that of (a); (c) facial image 18 printed using an inkjet method; (d) facial image 18 printed using a laser method; and (e) facial image 18 printed using a dye-sublimation thermal transfer method.

[0056] As shown in Figure 13, these Fourier transform images are different from one another, and it is clear that a genuine ID card 10 on which a facial image 18 has been printed using a fusion thermal transfer method at a specific resolution can be distinguished from a fake ID card 10 on which a facial image 18 has been printed using a different printing method or resolution by comparing the Fourier transform images. Note that since the Fourier transform images are point-symmetric with respect to the origin O, it is sufficient to compare only two adjacent quadrants of the four quadrants around the origin O. Figure 13 shows the two quadrants above the origin O.

[0057] The authenticity determination device 3 creates a Fourier transform image 210 for the facial image 18 of the ID card 10 to be determined for authenticity by the steps of S41 to S45, and uses this as the Fourier transform image 210 to be evaluated, and calculates an evaluation value regarding the difference between this and the Fourier transform image for the facial image 18 of the positive ID card 10 (referred to as the positive Fourier transform image) (S46).

[0058] In this embodiment, a point in the positive Fourier transform image that is brighter than its surroundings is defined as a bright point, and a predetermined range including the position of the bright point is set as the inspection range. FIG. 14(a) illustrates an example of the position of the bright point P and the inspection range D in the positive Fourier transform image 220. The position of the bright point P can be set as a position where the bright point P is estimated to appear in a Fourier transform image 220 that is created in advance for a large number of facial images 18 on positive ID cards 10 using the same method as the Fourier transform image 210 to be evaluated, following the steps S41 to S45. However, the method for setting the position of the bright point P is not limited to this. Furthermore, the inspection range D may be set in any manner as long as it is a range in the vicinity of the bright point P.

[0059] Then, in S46, for the Fourier transform image 210 to be evaluated, the above-mentioned bright spot P and the inspection range D are superimposed as shown in Fig. 14(b), and the position with the highest brightness within the inspection range D is detected. T is an example, and indicates the position with the highest brightness within the inspection range D at the bottom left.

[0060] 14(c), for each inspection range D of the Fourier transform image 210 to be evaluated, the authenticity determination device 3 determines the distance L between the position of the bright spot P in the positive Fourier transform image 220 and the position T with the highest brightness in the inspection range D, and calculates a value L / V by dividing the distance L by a predetermined coefficient V. Then, the total sum Σ(L / V) of the values L / V determined for each inspection range D is calculated as the evaluation value. The coefficient V is a value according to the brightness of the position T, and the brighter the position T, the larger the value.

[0061] The value L / V becomes smaller as the bright point in the Fourier transform image 210 to be evaluated is closer to the bright point P. Therefore, if the evaluation value Σ(L / V) is small, the Fourier transform image 210 to be evaluated is similar to the positive Fourier transform image 220.

[0062] The authenticity determination device 3 compares the evaluation value Σ(L / V) obtained as described above with a threshold value to determine authenticity (S47), and if the evaluation value Σ(L / V) is less than the threshold value, determines that the ID card 10 is authentic (S5; YES), and if the evaluation value Σ(L / V) is greater than or equal to the threshold value, determines that the ID card 10 is not authentic (S5; NO).

[0063] In this embodiment, the captured image (JPEG image) of the ID card 10 is converted to a grayscale image because, with a JPEG image, color information changes when the original data is compressed into JPEG format (brightness information is preserved). On the other hand, some image formats preserve color information. In such cases, grayscale conversion is not performed, and the above-mentioned evaluation value Σ(L / V) can be calculated for each RGB component of the area image Im, and the sum of the evaluation values Σ(L / V) calculated for each RGB component can be compared with a threshold. Calculating the evaluation value Σ(L / V) for each RGB component and using it to determine authenticity improves the accuracy of the authenticity determination.

[0064] As described above, in this embodiment, the spatial frequency characteristics of the facial image 18 on the ID card 10 differ depending on the printing method, printing resolution, etc. of the facial image 18, and by performing authenticity determination based on the spatial frequency characteristics, it is possible to suitably distinguish between a genuine ID card 10 on which the facial image 18 is printed using a specific printing method, printing resolution, etc., and an inauthentic ID card 10 on which the facial image 18 is printed using a different printing method, printing resolution, etc.

[0065] More specifically, regarding the above-mentioned authenticity determination, a Fourier transform image 210 showing the spatial frequency characteristics of the facial image 18 on the ID card 10 to be subjected to the authenticity determination is created, an evaluation value relating to the difference with the positive Fourier transform image 220 is calculated, and the authenticity of the ID card 10 can be determined using the evaluation value.

[0066] The evaluation value can be calculated using a bright spot P that appears as a feature of the positive Fourier transform image 220, and the distance L between the position of the bright spot P and a high-luminance position T that appears in the Fourier transform image 210 of the evaluation target within the inspection range D that includes the bright spot P. If this distance L is small, the Fourier transform image 210 of the evaluation target is similar to the positive Fourier transform image 220, and the authenticity of the ID card 10 can be said to be high.

[0067] In addition, the brightness at the above position T of the Fourier transform image 210 to be evaluated is also a factor that can determine the difference between the Fourier transform image 210 to be evaluated and the positive Fourier transform image 220, and by using a coefficient V corresponding to the brightness, authenticity can be determined more accurately.

[0068] Furthermore, the authenticity determination device 3 of this embodiment can determine the authenticity of a photographed image of an ID card 10 sent from a user terminal 5, thereby constructing an authenticity determination system 1 using the authenticity determination device 3 and the user terminal 5 via a network.

[0069] However, the present invention is not limited to the above-described embodiment. For example, in the present embodiment, authenticity determination is performed as identity verification when opening an account, but the application scene or purpose of the authenticity determination of the present embodiment is not particularly limited.

[0070] In this embodiment, the authenticity is determined using the evaluation value Σ(L / V), but it is also possible to use other values that can express the difference in the Fourier transform images such as those shown in Figures 13(a) to 13(e). Furthermore, the authenticity determination can be based on the spatial frequency characteristics of the facial image 18, and is not limited to the use of the difference in the Fourier transform images.

[0071] In this embodiment, the facial image 18 of the positive ID card 10 is printed using a fusion thermal transfer method, but the facial image 18 may be printed using other printing methods and be considered positive. In such cases, it is still possible to determine the authenticity based on the spatial frequency characteristics of the facial image 18, for example, by using an evaluation value that can express the difference between Fourier transform images such as those shown in Figures 13(a) to (e).

[0072] Furthermore, in this embodiment, the authenticity of the ID card 10 is determined based on the spatial frequency characteristics of the facial image 18, but this is not limiting. As long as the printing method, printing resolution, model of printer used for printing, and other factors are known for a specific portion of the ID card 10, the authenticity can be determined based on the spatial frequency characteristics of that portion using a method similar to that of this embodiment, even if it is a portion other than the facial image 18. For example, this may be a solid portion or a specific mark portion on the ID card 10. However, the facial image 18 has a relatively large area with little color change, making it suitable for authenticity determination based on spatial frequency characteristics.

[0073] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications or alterations within the scope of the technical ideas disclosed herein, and it is understood that these modifications also fall within the technical scope of the present invention. [Explanation of symbols]

[0074] 1: Authenticity determination system 3: Authenticity determination device 5: User terminal 10: ID card 18:Facial image 100: Thermal transfer printer 110: Thermal head 111: Heating element 210, 220: Fourier transform images 301: Receiving method 302: Authenticity determination means

Claims

1. An apparatus for determining the authenticity of an identification card on which a facial image is printed by a specific model of printer using a specific printing method and printing resolution, An authenticity determination device characterized by having an authenticity determination means that uses a grayscale image obtained by converting a photographed image of the identification card into a grayscale image and determines the authenticity of the identification card based on the spatial frequency characteristics of the facial image of the identification card by comparing a Fourier transform image that shows the spatial frequency characteristics of the facial image of the identification card with a positive Fourier transform image that shows the spatial frequency characteristics of the facial image of a genuine identification card in which the facial image is printed by the specific model of printer using the specific printing method and printing resolution.

2. A device for determining the authenticity of a personal identification card, an authenticity determination means for determining the authenticity of the identification card based on the spatial frequency characteristics of a predetermined portion of the identification card using a photographed image of the identification card; the authenticity determination means creates a Fourier transform image of the predetermined portion, determines an evaluation value relating to a difference between the Fourier transform image and a positive Fourier transform image as a Fourier transform image to be evaluated, and performs an authenticity determination based on the evaluation value; An authenticity determination device characterized in that the evaluation value is calculated using the distance between the position of a bright point in a positive Fourier transform image of the object to be evaluated and the position of the highest brightness in an inspection range that includes the position of the bright point in the Fourier transform image of the object to be evaluated.

3. 3. The authenticity determination device according to claim 2, wherein the predetermined portion is a facial image.

4. 3. The authenticity determination device according to claim 2, wherein the evaluation value is calculated using the distance and a coefficient corresponding to the luminance of the position with the highest luminance in the inspection range of the Fourier transform image of the evaluation target.

5. 5. The authenticity determining device according to claim 1, further comprising a receiving means for receiving the photographed image from a user terminal.

6. Computer, An apparatus for determining the authenticity of an identification card on which a facial image is printed by a specific model of printer using a specific printing method and printing resolution, A program for causing the device to function as an authenticity determination device having an authenticity determination means that uses a grayscale image obtained by converting a photograph of the identification card into a grayscale image to determine the authenticity of the identification card based on the spatial frequency characteristics of the facial image on the identification card by the difference between a Fourier transform image that shows the spatial frequency characteristics of the facial image on the identification card and a positive Fourier transform image that shows the spatial frequency characteristics of the facial image on a genuine identification card in which the facial image has been printed by the specific model of printer using the specific printing method and printing resolution.

7. Computer, A device for determining the authenticity of a personal identification card, an authenticity determination means for determining the authenticity of the identification card based on the spatial frequency characteristics of a predetermined portion of the identification card using a photographed image of the identification card; the authenticity determination means creates a Fourier transform image of the predetermined portion, determines an evaluation value relating to a difference between the Fourier transform image and a positive Fourier transform image as a Fourier transform image to be evaluated, and performs an authenticity determination based on the evaluation value; A program for causing the device to function as an authenticity determination device in which the evaluation value is determined using the distance between the position of a bright point in a positive Fourier transform image of the object to be evaluated and the brightest position in an inspection range that includes the position of the bright point in the Fourier transform image of the object to be evaluated.

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