Authenticity verification system and authenticity verification method

Abstract

The present invention provides an issuing device comprising a first processor, wherein the first processor acquires, as a first captured image, an image obtained by capturing, with a camera, a verification image printed on an information medium. Also provided is an authenticity verification device comprising a second processor, wherein the second processor acquires, as a second captured image, an image obtained by capturing, with a camera, a verification image printed on an information medium to be verified, predicts a density change at a time when the second captured image is acquired on the basis of an elapsed time from a time when the first captured image is obtained and thereby generates a corrected image obtained by applying a density correction to the first captured image, and determines, on the basis of a differential image obtained by acquiring per-pixel differences between the second captured image and the corrected image, a verification region where the first captured image and the second captured images are to be compared.

Description

Technical Field

[0001] The technology of the present disclosure relates to an authenticity verification system and an authenticity verification method.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2002-007977 discloses an authentication system for authenticating the validity of an ID (identification) card such as an employee ID card or a student ID card. Since this authentication system uses an ID card incorporating an IC (Integrated Circuit) memory to perform highly secure and robust authentication, it takes time and is costly to issue the ID card.

[0003] ID cards are not only those that are used for a long time such as employee ID cards or student ID cards. Among ID cards, there are also those that are assumed to be used temporarily for a short period, such as visitor ID cards used at events such as exhibitions. For ID cards assumed to be used temporarily like this, a simple information medium in which the user's image, identification information, etc. are printed on a base material such as paper is used.

[0004] However, since such a simple information medium can be forged relatively easily, authenticity becomes a problem. In order to prevent forgery of such an information medium, for example, Japanese Patent Application Laid-Open No. 2017-013399 proposes printing micro characters of extremely small size on the base material. Also, Japanese Patent Application Laid-Open No. 2004-102562 proposes performing verification using a random pattern created by the fibers of paper in order to verify the authenticity (i.e., originality) of a paper medium as a base material.

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described in JP-A-2017-013399 and JP-T-2004-102562, in order to verify the authenticity of an information medium, it is necessary to image a verification area on the information medium and verify whether the information included in the captured image obtained by imaging matches the pre-registered information.

[0006] However, such a simple information medium may be soiled or damaged on the surface while being held by the user after issuance. When dirt or scratches occur in the verification area on the information medium, the verification accuracy will decrease. Therefore, a authenticity verification system that uses a simple information medium and has high verification accuracy is desired.

[0007] The technology of the present disclosure aims to provide an authenticity verification system and an authenticity verification method that use a simple information medium and have high verification accuracy.

Means for Solving the Problems

[0008] The authenticity verification system of the present disclosure is an authenticity verification system including an issuing device that issues an information medium by printing a verification image on a base material based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image. The issuing device includes a first processor. The first processor acquires, as a first captured image, an image obtained by imaging a verification image printed on the information medium with a camera. The verification device includes a second processor. The second processor acquires, as a second captured image, an image obtained by imaging a verification image printed on the information medium to be verified with a camera. Based on the elapsed time from the time when the first captured image was acquired, the second processor predicts a density change at the time when the second captured image was acquired, thereby generating a corrected image obtained by performing density correction on the first captured image. Based on a difference image obtained by taking a difference between the second captured image and the corrected image pixel by pixel, the verification device determines a verification area for verifying the first captured image and the second captured image.

[0009] The first processor registers the first captured image in the storage device, and the second processor acquires the first captured image registered in the storage device. It is preferable that the second processor performs density correction based on the elapsed time from the time when the first captured image was registered in the storage device.

[0010] It is preferable that the second processor determines, as a collation area, an area where the absolute value of the pixel value of the difference image is equal to or less than a threshold value.

[0011] It is preferable that the second processor performs density correction based on a table representing the relationship between the elapsed time and the density change.

[0012] It is preferable that the second processor collates the authenticity of the information medium by comparing the information included in the collation area for the first captured image and the second captured image.

[0013] The information is preferably the spatial frequency characteristics.

[0014] The authenticity verification method of the present disclosure is an authenticity verification method using an issuing device that issues an information medium by printing a verification image on a substrate based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image. The first captured image acquisition step of acquiring, as the first captured image, an image obtained by imaging, with a camera, the verification image printed on the information medium is executed by the issuing device, and the second captured image acquisition step of acquiring, as the second captured image, an image obtained by imaging, with a camera, the verification image printed on the information medium to be verified, and the density correction step of generating a corrected image obtained by performing density correction on the first captured image by predicting the density change at the time when the second captured image was acquired based on the elapsed time from the time when the first captured image was acquired, and the collation area determination step of determining a collation area for collating the first captured image and the second captured image based on a difference image obtained by taking a difference between the second captured image and the corrected image for each pixel are executed by the verification device.

[0015] The authenticity verification system of the present disclosure is an authenticity verification system including an issuing device that issues an information medium by printing a verification image on a base material based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image. The issuing device includes a first processor. The first processor acquires, as a first captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium. The verification device includes a second processor. The second processor acquires, as a second captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium to be verified. Based on a division image obtained by dividing the second captured image and the verification image data pixel by pixel, the second processor determines a verification area for verifying the first captured image and the second captured image.

[0016] Preferably, the second processor determines, as the verification area, an area where the pixel value of the division image is equal to or less than a threshold value.

[0017] Preferably, the second processor verifies the authenticity of the information medium by comparing the information included in the verification area for the first captured image and the second captured image.

[0018] Preferably, the information is spatial frequency characteristics.

[0019] The authenticity verification method of the present disclosure is an authenticity verification method using an issuing device that issues an information medium by printing a verification image on a base material based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image. The method includes causing the issuing device to execute a first captured image acquisition step of acquiring, as a first captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium, causing the verification device to execute a second captured image acquisition step of acquiring, as a second captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium to be verified, and a verification area determination step of determining a verification area for verifying the first captured image and the second captured image based on a division image obtained by dividing the second captured image and the verification image data pixel by pixel.

Effect of the Invention

[0020] According to the technology of the present disclosure, it is possible to provide an authenticity verification system and an authenticity verification method that use a simple information medium and have high verification accuracy.

Brief Description of the Drawings

[0021]

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Mode for Carrying Out the Invention

[0022] [First Embodiment] FIG. 1 shows an example of an authenticity verification system 2 according to the first embodiment of the technology of the present disclosure. As shown in FIG. 1, the authenticity verification system 2 includes an issuing device 10 and a verification device 20. The verification device 20 is connected to a database 30 for registering various types of data. The issuing device 10 is installed, for example, at the reception counter of an event venue and issues an admission permit (hereinafter referred to as an admission ticket) 40. The issuing device 10 is, for example, a digital camera with a printer. The issuing device 10 issues the admission ticket 40 by printing information on an instant film 41. Note that the admission ticket 40 is an example of the "information medium" according to the technology of the present disclosure.

[0023] The issuing device 10 is connected to an operation display device 14 operated by a participant 13 who participates in the event. The operation display device 14 is, for example, a display device with a touch panel. The operation display device 14 guides, for example, by video, the method of issuing the admission ticket 40 to the participant 13 who visits the reception counter. The operation display device 14 may be a personal computer or a tablet terminal or the like.

[0024] The admission ticket 40 is, for example, an ID card for the organizer of the event to collate the participant 13 at the entrance gate to the event venue and permit entry to the legitimate participant 13. The admission ticket 40 is issued to each of a plurality of participants 13 who wish to enter the event venue. The admission ticket 40 is printed with a face image 42 of the participant 13 photographed by the issuing device 10 and a verification image 43. The verification image 43 is a pattern image for verifying that the admission ticket 40 to be verified is not a forged one but is duly issued by the issuing device 10, that is, for verifying the authenticity of the admission ticket 40.

[0025] The issuing device 10 has a camera function for photographing the face of the participant 13 and a printing function for printing the face image 42 including the photographed face. The issuing device 10 is, for example, an instant camera having a printing function capable of immediately printing the photographed image. With such a printing function, the issuing device 10 immediately issues an admission ticket 40 printed with information including the face image 42 of the participant 13 and the verification image 43 at the time of reception when the participant 13 enters the event venue. Also, in this example, the issuing device 10 includes a control function for controlling the operation display device 14 and a communication function with the verification device 20, and functions as a reception device for receiving the entry of the participant 13 into the event venue.

[0026] The issuing device 10 prints information including the face image 42 and the reference image 43 of the participant 13 on the instant film 41 as a substrate (i.e., a recording medium), and outputs the instant film 41 with the information printed thereon as the admission ticket 40. The reference image 43 is, for example, a pattern image having a plurality of regions with different densities. The reference image data PV, which is digital data for printing the reference image 43, is stored in, for example, the database 30. The issuing device 10 prints the reference image 43 on the instant film 41 based on the reference image data PV acquired from the database 30 via the reference image 43. The reference image data PV is, for example, color image data, and the reference image 43 is printed in color on the instant film 41.

[0027] Also, immediately after printing the information including the face image 42 and the reference image 43 on the instant film 41, the issuing device 10 acquires the first captured image P1 by capturing the reference image 43. The first captured image P1 is added with the time when the reference image 43 was captured (hereinafter referred to as the first capture time) T1. The issuing device 10 transmits the first captured image P1 to the verification device 20. When the verification device 20 receives the first captured image P1 from the issuing device 10, the verification device 20 registers the first captured image P1 in the database 30. For example, the first captured image P1 is registered in the database 30 in association with the identification information for identifying the admission ticket 40 issued by the issuing device 10.

[0028] The database 30 is a storage device having a data storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and a control circuit. The database 30 stores data in response to a storage request from the collation device 20, searches for data in response to a search request from the collation device 20, and returns a search result to the collation device 20. The database 30 may be provided inside the collation device 20 or outside the collation device 20. When provided outside the collation device 20, the database 30 and the collation device 20 are communicably connected via a network such as a LAN (Local Area Network).

[0029] The participant 13, for example, holds the admission ticket 40 issued by the issuing device 10 and heads towards the entrance gate of the event venue, and presents the admission ticket 40 to a staff member (not shown) who manages the entrance gate. The staff member holds an electronic terminal 50 and collates the authenticity of the admission ticket 40 by imaging the collation image 43 of the admission ticket 40 presented by the participant 13. The electronic terminal 50 is, for example, a tablet terminal with a camera and is communicably connected to the collation device 20 wirelessly or by wire.

[0030] The staff member operates the electronic terminal 50 to image the collation image 43 of the admission ticket 40. The electronic terminal 50 acquires a second captured image P2 by imaging the collation image 43. The time when the collation image 43 is imaged (hereinafter referred to as the second imaging time) T2 is added to the second captured image P2. When the electronic terminal 50 acquires the second captured image P2, it transmits the second captured image P2 to the collation device 20.

[0031] The verification device 20 is composed of a personal computer, a server device, or the like. When the verification device 20 receives the second captured image P2 from the electronic terminal 50, it acquires the first captured image P1 from the database 30 and performs verification between the first captured image P1 and the second captured image P2. When the verification is completed, the verification device 20 transmits the verification result to the electronic terminal 50. The staff at the entrance gate determines whether the participant 13 can enter the event venue based on the verification result received by the electronic terminal 50 from the verification device 20.

[0032] Note that the electronic terminal 50 may be installed at the entrance gate. In this case, when the participant 13 operates the electronic terminal 50, the electronic terminal 50 may capture the verification image 43 of the admission ticket 40.

[0033] FIG. 2 shows an example of the external configuration of the issuing device 10. As shown in FIG. 2, the issuing device 10 has a box-shaped housing that is rounded as a whole. As described above, the issuing device 10 in this example is an instant camera, and inside the housing, a film pack 44 of the instant film 41 is loaded in a replaceable manner. The film pack 44 contains a plurality of (for example, 10) unused instant films 41.

[0034] A printer 18 (see FIG. 3) is provided inside the issuing device 10. The printer 18 prints information including the face image 42 and the verification image 43 on the instant film 41. The printed instant film 41 is discharged to the outside from a discharge port 45 formed at the upper part of the housing. It is known that the color density of the image printed on the instant film 41 changes over time. The characteristics of the change in color density over time are different for each printed color. Hereinafter, "color density" may also be simply referred to as "density".

[0035] FIG. 3 shows an example of the internal configuration of the issuing device 10. As shown in FIG. 3, the issuing device 10 includes a computer 15, a first camera 16, a second camera 17, and a printer 18. The computer 15 includes a CPU (Central Processing Unit) 15A, an NVM (Non-Volatile Memory) 15B, a RAM (Random Access Memory) 15C, and a communication I / F (interface) 15D. The CPU 15A, the NVM 15B, the RAM 15C, the communication I / F 15D, the first camera 16, the second camera 17, and the printer 18 are connected to each other via a bus 19.

[0036] The CPU 15A controls the entire issuing device 10. The NVM 15B is, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory), but is not limited thereto and may be a flash memory. The RAM 15C is a volatile memory and is used as a work memory by the CPU 15A.

[0037] The communication I / F 15D is realized by, for example, a device having an FPGA (Field-Programmable Gate Array). The communication I / F 15D is connected to the operation display device 14 and communicates with the operation display device 14. Further, the communication I / F 15D is connected to the verification device 20 and communicates with the verification device 20.

[0038] The first camera 16 and the second camera 17 are each an imaging device composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor and an optical system. The first camera 16 generates a face image 42 including the face of the participant 13 by imaging the area including the face through a lens 16A (see FIG. 2) provided on the front surface of the housing. The second camera 17 is a built-in camera provided inside the housing. When the instant film 41 is output from the printer 18, the second camera 17 generates the above-described first captured image P1 by imaging the reference image 43 printed on the instant film 41, and adds the first capture time T1 to the first captured image P1. The second camera 17 is an example of the "camera" according to the technology of the present disclosure.

[0039] In this example, the printer 18 is an instant photo printer that prints an image on an instant film 41 as a base material. The printer 18 uses, for example, an image display device such as an LCD (Liquid Crystal Display) as an exposure device. Inside the printer 18, the exposure device is arranged in a posture where the image display surface for displaying an image faces the photosensitive surface of the instant film 41. The printer 18 exposes the photosensitive material of the instant film 41 by displaying the image to be printed on the exposure device. As described above, the instant film 41 is a film that develops color with a photosensitive material containing a silver salt. Further, since the printer 18 uses the instant film 41 as a base material, it is naturally a printer using a density modulation method that forms an image by changing the color density of the base material according to the exposure amount.

[0040] The NVM15B stores an admission ticket issuing program 60. The CPU15A reads the admission ticket issuing program 60 from the NVM15B into the RAM15C, and by executing processing based on the read admission ticket issuing program 60, functions as a first imaging control unit 62, a second imaging control unit 63, and a printing control unit 64. The first imaging control unit 62 controls the imaging operation by the first camera 16. The second imaging control unit 63 controls the imaging operation by the second camera 17. The printing control unit 64 controls the printing operation by the printer 18. The first imaging control unit 62, the second imaging control unit 63, and the printing control unit 64 cooperate to perform the admission ticket issuing process. The admission ticket issuing process starts in response to an issuance request RQ input from the operation display device 14.

[0041] In addition to the admission ticket issuing program 60, the NVM15B stores a printing template 61 for the admission ticket 40 and verification image data PV. The printing template 61 is data that defines the arrangement etc. of the face image 42 and the verification image 43 to be printed on the instant film 41. The verification image data PV is acquired from the database 30 and stored in the NVM15B.

[0042] FIG. 4 shows an example of the printing process of the admission ticket 40 using the printing template 61. As shown in FIG. 4, the printing template 61 defines a first area 61A for arranging the face image 42 and a second area 61B for arranging the verification image 43. The printing control unit 64 creates printing data 65 by assigning the face image 42 acquired by the first camera 16 to the first area 61A and the verification image data PV to the second area 61B. The printing control unit 64 causes the printer 18 to execute a printing operation based on the created printing data 65. By performing printing on the instant film 41 based on the printing data 65, the admission ticket 40 is created.

[0043] FIG. 5 shows an example of the reception process by the operation display device 14. The operation display device 14 is operated by the participant 13. First, as shown in FIG. 5, on the display screen of the operation display device 14, an admission ticket creation button 70 that prompts the creation of the admission ticket 40 is displayed together with a message such as "Welcome to the Advanced Industrial Technology Exhibition!". When the admission ticket creation button 70 is touched by the participant 13, the display screen transitions.

[0044] On the transitioned display screen, a shooting button 72 that prompts the execution of shooting is displayed together with a preview image 71 captured by the first camera 16. Also, a message "Take a face image to be printed on the admission ticket. Touch the shooting button to execute shooting." is displayed on the display screen. When the shooting button 72 is touched by the participant 13, after the imaging operation by the first camera 16, a printing operation by the printer 18 is performed.

[0045] FIG. 6 shows an example of the discharge process of the admission ticket 40. As shown in FIG. 6, the admission ticket 40 printed by the printer 18 is imaged by the second camera 17 inside the issuing device 10 before being output from the printer 18 and discharged from the discharge port 45. The second camera 17 generates a first captured image P1 by imaging the area including the verification image 43 printed on the admission ticket 40, and adds the first imaging time T1 to the first captured image P1. The first captured image P1 is registered in the database 30 via the verification device 20.

[0046] FIG. 7 shows an example of the internal configuration of the electronic terminal 50. As shown in FIG. 7, the electronic terminal 50 includes a computer 51, a camera 52, an operation display device 53, and a speaker 54. The computer 51 includes a CPU 51A, an NVM 51B, a RAM 51C, and a communication I / F 51D. The CPU 51A, the NVM 51B, the RAM 51C, the communication I / F 51D, the camera 52, the operation display device 53, and the speaker 54 are connected to each other via a bus 55. The communication I / F 51D communicates with the verification device 20. The camera 52 is an imaging device composed of, for example, a CMOS image sensor and an optical system. The operation display device 53 is, for example, a display device with a touch panel.

[0047] As described above, the electronic terminal 50 is, for example, a tablet terminal with a camera and is operated by a staff member who manages the entrance gate. As shown in FIG. 8, for example, the staff member holds the electronic terminal 50 and captures a verification image 43 of the entrance ticket 40 presented by the participant 13. At this time, on the display screen of the operation display device 53, a preview image 56 of the captured image including the verification image 43 captured by the camera 52 and a capture button 57 for prompting the execution of shooting are displayed.

[0048] When the capture button 57 is touched by the staff member, an imaging operation of the area including the verification image 43 is performed by the camera 52. The camera 52 generates a second captured image P2 and adds a second capture time T2 to the second captured image P2. The second captured image P2 generated by the camera 52 is transmitted to the verification device 20 via the communication I / F 51D.

[0049] FIG. 9 shows an example of the internal configuration of the verification device 20. As shown in FIG. 9, the verification device 20 includes a computer 21. The computer 21 includes a CPU 21A, an NVM 21B, a RAM 21C, and a communication I / F 21D. The CPU 21A, the NVM 21B, the RAM 21C, and the communication I / F 21D are connected to each other via a bus 22. The communication I / F 21D communicates with the issuing device 10, the electronic terminal 50, and the database 30.

[0050] The NVM21B stores a collation program 23. The CPU21A reads the collation program 23 from the NVM21B into the RAM21C and executes processing based on the read collation program 23, thereby functioning as an authenticity collation unit 24. When the authenticity collation unit 24 receives the second captured image P2 from the collation device 20, it acquires the first captured image P1 of the corresponding admission ticket 40 from the database 30 and collates the first captured image P1 with the second captured image P2.

[0051] In addition to the collation program 23, the NVM21B stores a density change prediction table 25 and a threshold value TH. Although details will be described later, the authenticity collation unit 24 determines a region (hereinafter referred to as a collation region) for collating the first captured image P1 with the second captured image P2 by using the density change prediction table 25 and the threshold value TH. After performing collation based on the collation region, the authenticity collation unit 24 transmits a collation result CR to the electronic terminal 50.

[0052] Since the admission ticket 40 is issued by the issuing device 10 at the reception counter and then carried around by the participant 13, there is a risk that dirt or scratches may adhere to the surface. In particular, when dirt or scratches occur on the collation image 43 of the admission ticket 40, the dirt is reflected in the second captured image P2 acquired by the electronic terminal 50 at the entrance gate, resulting in a decrease in the collation accuracy between the first captured image P1 and the second captured image P2. When the participant 13 repeatedly enters and exits the event venue, the dirt or scratches on the admission ticket 40 accumulate, further reducing the collation accuracy.

[0053] In the first embodiment, the authenticity collation unit 24 performs processing to detect a contaminated region in the collation image 43 based on the first captured image P1 and the second captured image P2, and determines a region other than the contaminated region as the collation region. In the present disclosure, the contaminated region includes not only a region where the image becomes unclear due to dirt but also a region where the image becomes unclear due to scratches or the like.

[0054] FIG. 10 shows an example of the functional configuration of the authenticity verification unit 24. As shown in FIG. 10, the authenticity verification unit 24 includes an elapsed time calculation unit 80, a density correction unit 81, grayscale processing units 82 and 83, a difference processing unit 84, a verification region determination unit 85, and a verification unit 86.

[0055] The elapsed time calculation unit 80 calculates the elapsed time by subtracting the first imaging time T1 added to the first imaging image P1 from the second imaging time T2 added to the second imaging image P2. This elapsed time corresponds to the time from when the admission ticket 40 is issued by the reception counter until the admission ticket 40 is verified at the admission gate.

[0056] The density correction unit 81 corrects the density of the first imaging image P1 based on the elapsed time calculated by the elapsed time calculation unit 80 and the density change prediction table 25 stored in the NVM 21B. The density change prediction table 25 is data representing the relationship between the elapsed time and the density change. That is, the density correction unit 81 predicts the density change at the second imaging time T2 when the second imaging image P2 is acquired based on the elapsed time from the first imaging time T1 when the first imaging image P1 is acquired, and thus corrects the density of the first imaging image P1.

[0057] Since the characteristics of the change over time in the color density of the image printed on the instant film 41 differ for each color, the density correction unit 81 performs density correction for each color, for example, R (red), green (G), and blue (B). In the density change prediction table 25, density change characteristics representing the relationship between the elapsed time and the density change are recorded for each of the colors R, G, and B. The corrected image P1c for which density correction has been performed by the density correction unit 81 has a density approximately the same as that of the second imaging image P2.

[0058] The grayscale processing unit 82 performs grayscale processing to convert the corrected image P1c generated by the density correction unit 81 into a monochrome image, and inputs the grayscale corrected image P1c to the difference processing unit 84. Similarly, the grayscale processing unit 83 performs grayscale processing to convert the second imaging image P2 into a monochrome image, and inputs the grayscale second imaging image P2 to the difference processing unit 84.

[0059] The difference processing unit 84 generates a difference image PS by taking the difference between the corrected image P1c and the second captured image P2 for each pixel. In the present embodiment, for example, the difference processing unit 84 generates a difference image PS having positive pixel values by taking the absolute value of the difference value for each pixel.

[0060] The matching region determination unit 85 determines a matching region CA for matching the first captured image P1 and the second captured image P2 based on the difference image PS. Specifically, the matching region determination unit 85 uses the threshold value TH stored in the NVM 21B to determine, as the matching region CA, a region where the absolute value of the pixel value of the difference image PS is less than or equal to the threshold value TH.

[0061] The matching unit 86 collates the authenticity of the admission ticket 40 by comparing the information (for example, spatial frequency characteristics) included in the matching region CA determined by the matching region determination unit 85 for the first captured image P1 and the second captured image P2.

[0062] There is uncertainty in the color density of the image printed on the instant film 41. The uncertainty in color density means that even when the same image is printed on the same base material, the occurrence state of density unevenness is different each time it is printed. One reason for the occurrence of uncertainty in color density is that the distribution of the developing solution developed on the printing surface in the developing process does not become uniform over the entire printing surface. Another reason is that the distribution of the light-sensitive material, which is the coloring material that develops color, also becomes non-uniform over the entire printing surface. Thus, even in one instant film 41, non-uniformities such as the developing solution and the light-sensitive material occur on the printing surface.

[0063] That is, the comparison image 43 printed on the admission ticket 40 has unique density unevenness. The occurrence state of density unevenness appears as the spatial frequency characteristics of the color density of the image. Therefore, the technology of the present disclosure collates the authenticity of the admission ticket 40 by utilizing the fact that the spatial frequency characteristics of the color density of the image are different for each printing even when the same image is printed on the same base material.

[0064] If the first captured image P1 and the second captured image P2 are images obtained by capturing the verification image 43 of the same admission ticket 40, their spatial frequency characteristics will almost match. The verification unit 86 acquires the spatial frequency characteristics within the verification region CA for the first captured image P1 and the second captured image P2 by performing frequency analysis processing such as two-dimensional Fourier transform, and verifies the authenticity of the admission ticket 40 by comparing the acquired spatial frequency characteristics. If the degree of coincidence of the spatial frequency characteristics is equal to or greater than a predetermined value, the verification unit 86 determines that the admission ticket 40 is genuine; if the degree of coincidence is less than the predetermined value, the verification unit 86 determines that the admission ticket 40 is not genuine. The verification unit 86 transmits the verification result CR to the electronic terminal 50.

[0065] FIG. 11 schematically shows an example of a differential image generation process for generating a differential image PS based on the first captured image P1 and the second captured image P2. In FIG. 11, reference numeral 87 represents a contaminated area that has occurred in the verification image 43 of the admission ticket 40. Since the contaminated area 87 occurs after the first captured image P1 is acquired and before the second captured image P2 is acquired, it occurs only in the second captured image P2.

[0066] Since the second captured image P2 is a pattern image, the contrast difference between the contaminated area 87 and other areas is not necessarily large. Therefore, it is not easy to detect the contaminated area 87 based only on the second captured image P2. By performing the above-described differential image PS generation process, the areas other than the contaminated area 87 have pixel values close to 0, while the contaminated area 87 does not have a value close to 0. Therefore, the contaminated area 87 can be easily detected by generating the differential image PS.

[0067] FIG. 12 schematically shows an example of the determination process of the matching area CA by the matching area determination unit 85. As shown in FIG. 12, the matching area determination unit 85 determines the matching area CA from an area where the absolute value of the pixel value of the difference image PS is equal to or less than the threshold value TH (that is, an area other than the contamination area 87). Note that the matching area determination unit 85 may determine all areas other than the contamination area 87 as the matching area CA, or may determine a part of the areas other than the contamination area 87 as the matching area CA. The shape of the matching area CA determined by the matching area determination unit 85 is not limited, and the matching area CA may be rectangular.

[0068] FIG. 13 schematically shows an example of the matching process by the matching unit 86. As shown in FIG. 13, the matching unit 86 extracts an image from an area corresponding to the matching area CA of the first captured image P1, and performs frequency analysis on the extracted image to obtain the first spatial frequency characteristic F1. Similarly, the matching unit 86 extracts an image from an area corresponding to the matching area CA of the second captured image P2, and performs frequency analysis on the extracted image to obtain the second spatial frequency characteristic F2. The matching unit 86 compares the first spatial frequency characteristic F1 and the second spatial frequency characteristic F2, and determines whether the degree of coincidence is equal to or greater than a predetermined value, thereby generating a matching result CR. Note that a method based on machine learning can be used to calculate the degree of coincidence between the first spatial frequency characteristic F1 and the second spatial frequency characteristic F2.

[0069] The first captured image P1 and the second captured image P2 have different densities due to different imaging times, but since the density change occurs uniformly throughout the image, the difference in spatial frequency due to the different densities is small. Therefore, it is possible to perform matching using the first captured image P1 and the second captured image P2 with different densities. Note that the matching unit 86 may perform matching using the grayscale first captured image P1 and second captured image P2. Furthermore, the matching unit 86 may perform matching using the corrected image P1c and the second captured image P2.

[0070] FIG. 14 shows an example of the density change characteristics stored in the density change prediction table 25. The graph shown in FIG. 14 shows, for example, the change over time in the color density from the first imaging time T1 of the reference image 43. In FIG. 14, “0 minutes” indicates the time when the reference image 43 is printed on the instant film 41 by the printer 18. The first imaging time T1 is a time after several seconds or several tens of seconds have elapsed since the reference image 43 was printed on the instant film 41.

[0071] In the graph shown in FIG. 14, the vertical axis represents the luminance value. The higher the luminance value, the lower the density, and the lower the luminance value, the higher the density. In the instant film 41, since the color development progresses rapidly in a short time (about 3 minutes) immediately after printing, the density increase (i.e., the decrease in the luminance value) during this period is rapid. The subsequent density increase is gradual. Since the change over time in the color density of the instant film 41 has a tendency as shown in FIG. 14, it is possible to predict the color density of the instant film 41 based on the elapsed time after printing.

[0072] The density change prediction table 25 stores density change characteristics, for example, for each of the colors R, G, and B. The density change characteristics stored in the density change prediction table 25 are values derived, for example, by tests using an actual machine and / or computer simulations, etc. Note that instead of the density change prediction table 25, an arithmetic expression using the elapsed time from the first imaging time T1 as the independent variable and the color density as the dependent variable may be used.

[0073] FIG. 15 details an example of the density correction process. The density correction unit 81 obtains the amount of density change that changes between the first imaging time T1 and the second imaging time T2 based on the elapsed time calculated by the elapsed time calculation unit 80 and the density change characteristics stored in the density change prediction table 25. The density correction unit 81 generates a corrected image P1c by correcting each pixel value of the first captured image P1 using the obtained amount of density change as a correction value.

[0074] FIG. 16 will explain an example of the difference processing and the collation area determination processing in detail. As shown in FIG. 16, the difference processing unit 84 subtracts one of the corrected image P1c and the second captured image P2 from the other pixel by pixel, and generates a difference image PS by taking the absolute value of the subtracted value. Among the pixel values of the difference image PS, the pixel values other than the contamination area 87 become values close to 0.

[0075] The collation area determination unit 85 compares the pixel values of the difference image PS with a threshold value TH, and determines at least a part of the area below the threshold value TH as the collation area CA. The threshold value TH is set to a value that can separate the contamination area 87 and the collation area CA. The threshold value TH is, for example, a value derived by tests using an actual machine and / or computer simulations or the like.

[0076] Note that the difference processing unit 84 does not necessarily take the absolute value of the pixel values for which the difference is taken. In this case, since the pixel values of the difference image PS take positive and negative values, the threshold value TH may be set for the positive side and the negative side, respectively.

[0077] Next, the operation of the above configuration will be described with reference to the flowcharts shown in FIGS. 17 and 18. As shown in FIG. 17, first, the operation display device 14 determines whether or not the admission ticket creation button 70 (see FIG. 5) has been touched by the participant 13 who has visited the reception counter (step ST100). When the operation display device 14 determines that the admission ticket creation button 70 has been touched by the participant 13 (step ST100: YES), it changes the display screen and displays a preview image 71 and a shooting button 72 (step ST101). An image including the face of the participant 13 captured by the first camera 16 of the issuing device 10 is preview-displayed on the preview image 71.

[0078] Next, the operation display device 14 determines whether the shooting button 72 has been touched by the participant 13 (step ST102). If the operation display device 14 determines that the shooting button 72 has not been touched by the participant 13 (step ST102: NO), the process returns to step ST101, and the display of the preview image 71 continues. If the operation display device 14 determines that the shooting button 72 has been touched by the participant 13 (step ST102: YES), the issuing device 10 acquires the face image 42 by shooting an image including the face of the participant 13 with the first camera 16 (i.e., actual shooting) (step ST103).

[0079] Next, as shown in FIG. 4, the issuing device 10 causes the printer 18 to perform a printing operation based on the print template 61, the face image 42, and the print data 65 created from the verification image data PV, thereby printing the admission ticket 40 (step ST104). As shown in FIG. 6, when the admission ticket 40 is output from the printer 18, the issuing device 10 causes the second camera 17 to image the area including the verification image 43 printed on the admission ticket 40 (step ST105). Then, the issuing device 10 registers the first captured image P1 and the first capture time T1 acquired by the second camera 17 in the database 30 via the verification device 20 (step ST106).

[0080] After that, the participant 13 goes to the entrance gate with the admission ticket 40 issued by the issuing device 10, and the admission ticket 40 is verified at the entrance gate using the electronic terminal 50 held by the staff. The staff images the area including the verification image 43 of the admission ticket 40 with the camera 52 of the electronic terminal 50 (see FIGS. 7 and 8). The second captured image P2 acquired by the camera 52 is transmitted to the verification device 20 after the second capture time T2 is attached.

[0081] Next, as shown in FIG. 18, the collation device 20 determines whether it has received the second captured image P2 from the electronic terminal 50 (step ST200). When the collation device 20 determines that it has received the second captured image P2 (step ST200: YES), as shown in FIG. 9, it acquires the second captured image P2 and the second capture time T2 (step ST201). Then, the collation device 20 acquires the first captured image P1 and the first capture time T1 from the database 30 (step ST202).

[0082] Next, the elapsed time calculation unit 80 (see FIG. 10) calculates the elapsed time from the first capture time T1 to the second capture time T2 (step ST203). As shown in FIGS. 14 and 15, the density correction unit 81 generates a corrected image P1c by density-correcting the first captured image P1 based on the elapsed time and the density change characteristics stored in the density change prediction table 25 (step ST204). Then, the grayscale processing unit 82 grayscales the corrected image P1c, and the grayscale processing unit 83 grayscales the second captured image P2 (step ST205).

[0083] Next, as shown in FIGS. 11 and 16, the difference processing unit 84 generates a difference image PS by taking the difference between the corrected image P1c and the second captured image P2 (step ST206). As shown in FIGS. 12 and 16, the collation area determination unit 85 determines, based on the difference image PS, an area other than the contamination area 87 as the collation area CA (step ST207). As shown in FIG. 13, the collation unit 86 respectively acquires the first spatial frequency characteristic F1 and the second spatial frequency characteristic F2 from the areas corresponding to the collation area CA of the first captured image P1 and the collation area CA of the second captured image P2 (step ST208).

[0084] Next, the matching unit 86 performs matching between the first captured image P1 and the second captured image P2 by calculating the degree of coincidence between the first spatial frequency characteristic F1 and the second spatial frequency characteristic F2 (step ST209). Then, the matching unit 86 transmits the matching result CR to the electronic terminal 50 (step ST210). The staff at the entrance gate can determine whether to permit the entry of the participant 13 based on the matching result CR received by the electronic terminal 50.

[0085] As described above, according to the first embodiment, even when using the admission ticket 40, which is a simple information medium created by printing the matching image 43 on the instant film 41 as the base material, the matching accuracy of the admission ticket 40 can be improved.

[0086] In the first embodiment, the elapsed time calculation unit 80 calculates the elapsed time from the first imaging time T1 to the second imaging time T2. However, the time when the first captured image P1 is registered in the database 30 as the storage device may be recorded as the registration time, and the elapsed time from the registration time to the second imaging time T2 may be calculated. Also, the time when the matching image 43 is printed by the printer 18 may be recorded as the printing time, and the elapsed time from the printing time to the second imaging time T2 may be calculated. The first imaging time T1, the registration time, and the printing time are all examples of the "time when the first captured image is acquired" according to the technology of the present disclosure.

[0087] [Second Embodiment] Next, the second embodiment will be described. The processing by the verification device 20 in the second embodiment is different from that in the first embodiment. Hereinafter, the second embodiment will be described centering on the differences from the first embodiment.

[0088] FIG. 19 shows an example of the internal configuration of the verification device 20 according to the second embodiment. The verification program 23A stored in the NVM 21B in this embodiment is different from the verification program 23 in the first embodiment. That is, the authenticity verification unit 24A, which is a function realized by the CPU 21A executing processing based on the verification program 23A, is different from the authenticity verification unit 24 in the first embodiment.

[0089] In this embodiment, the authenticity verification unit 24A acquires the first captured image P1 from the database 30 and the second captured image P2 from the electronic terminal 50, but it is not necessary to acquire the first imaging time T1 and the second imaging time T2. In this embodiment, the authenticity verification unit 24A further acquires verification image data PV from the database 30.

[0090] FIG. 20 shows an example of the functional configuration of the authenticity verification unit 24A according to the second embodiment. As shown in FIG. 20, the authenticity verification unit 24A includes grayscale processing units 91 and 92, a division processing unit 93, a verification region determination unit 94, and a verification unit 95. The grayscale processing unit 91 performs grayscale processing to convert the verification image data PV into a monochrome image, and inputs the grayscale verification image data PV to the division processing unit 93. The grayscale processing unit 92 performs grayscale processing to convert the second captured image P2 into a monochrome image, and inputs the grayscale second captured image P2 to the division processing unit 93.

[0091] The division processing unit 93 generates a division image PD by dividing the verification image data PV and the second captured image P2 pixel by pixel. In this embodiment, for example, the division processing unit 93 generates the division image PD by dividing the pixel value of the verification image data PV by the pixel value of the second captured image P2.

[0092] The verification region determination unit 94 determines a verification region CA for verifying the first captured image P1 and the second captured image P2 based on the division image PD. Specifically, the verification region determination unit 94 uses the threshold value TH stored in the NVM 21B to determine, as the verification region CA, a region where the pixel value of the division image PD is equal to or less than the threshold value TH.

[0093] The verification unit 95 verifies the authenticity of the admission ticket 40 by comparing the information (for example, spatial frequency characteristics) included in the verification region CA determined by the verification region determination unit 94 for the first captured image P1 and the second captured image P2.

[0094] FIG. 21 illustrates the relationship between the densities of the first captured image P1, the second captured image P2, and the reference image data PV. As shown in FIG. 21, the image printed on the instant film 41 has a large density change immediately after printing, and gradually changes linearly with time as time elapses. The density of the image after sufficient time has elapsed is linearly related to the density of the reference image data PV, rather than the density of the first captured image P1.

[0095] In FIG. 21, YL1 and YH1 represent two different densities (corresponding to luminance values) in the first captured image P1. Also, YL2 and YH2 represent two different densities in the second captured image P2. Furthermore, DL and DH represent two different densities in the reference image data PV. YL1, YL2, and DL are the densities of the corresponding same pixel. YH1, YH2, and DH are the densities of the corresponding same pixel.

[0096] Since the density of the second captured image P2 after sufficient time has elapsed since printing is not linear with the density of the first captured image P1, YL1 / YL2 ≠ YH1 / YH2. On the other hand, since the density of the second captured image P2 is linear with the density of the reference image data PV, the relationship DL / YL2 ≈ DH / YH2 holds. Therefore, by dividing the reference image data PV by the second captured image P2, a division image PD with a reduced density difference (i.e., reduced contrast) is generated.

[0097] FIG. 22 schematically shows an example of the division process and the collating area determination process. As shown in FIG. 22, by dividing the reference image data PV by the second captured image P2 by the division processing unit 93, a division image PD with a reduced contrast in the area other than the contamination area 87 is generated. Thus, due to the reduced contrast in the area other than the contamination area 87, the collating area determination unit 85 can detect the contamination area 87 with high accuracy and determine the collating area CA.

[0098] FIG. 23 will explain an example of the division process and the collation area determination process in detail. As shown in FIG. 23, the division processing unit 93 generates a division image PD by dividing one of the collation target image data PV and the second captured image P2 by the other. Among the pixel values of the division image PD, the pixel values other than the contamination area 87 become substantially constant values.

[0099] The collation area determination unit 94 compares the pixel values of the division image PD with a threshold value TH, and determines at least a part of the area below the threshold value TH as the collation area CA. The threshold value TH is a value determined based on, for example, the average value of the pixel values of the division image PD.

[0100] Next, the operation of the above configuration will be described with reference to the flowchart shown in FIG. 24. Since the issuance process by the issuing device 10 is the same as that in the first embodiment, the description will be omitted. However, in the second embodiment, since it is not necessary to calculate the elapsed time, it is not necessary to register the first imaging time T1 in the database 30. Also, in the second embodiment, it is sufficient to acquire at least the second captured image P2 from the electronic terminal 50, and it is not necessary to acquire the second imaging time T2.

[0101] FIG. 24 shows an example of the flow of the collation process according to the second embodiment. As shown in FIG. 24, the collation device 20 determines whether or not it has received the second captured image P2 from the electronic terminal 50 (step ST300). When the collation device 20 determines that it has received the second captured image P2 (step ST300: YES), it acquires the second captured image P2 as shown in FIG. 19 (step ST301). Then, the collation device 20 acquires the collation target image data PV from the database 30 (step ST302).

[0102] Next, the grayscale processing unit 91 grayscales the verification image data PV, and the grayscale processing unit 92 grayscales the second captured image P2 (step ST303). As shown in FIGS. 22 and 23, the division processing unit 93 generates a division image PD by dividing the verification image data PV by the second captured image P2 (step ST304). Then, based on the division image PD, the verification region determination unit 94 determines a region other than the contamination region 87 as the verification region CA (step ST305). Steps ST306 to ST308 after this are the same as steps ST208 to ST210 shown in FIG. 18.

[0103] As described above, according to the second embodiment, even when using the admission ticket 40, which is a simple information medium created by printing the verification image 43 on the instant film 41 as the base material, the verification accuracy of the admission ticket 40 can be improved. Also, in the second embodiment, the verification region CA can be determined without using the first imaging time T1 and the second imaging time T2.

[0104] In the second embodiment, the verification region determination unit 94 determines the verification region CA using one threshold value TH as shown in FIG. 23. However, as shown in FIG. 25, the verification region CA may be determined using two threshold values, the first threshold value TH1 and the second threshold value TH2. The first threshold value TH1 and the second threshold value TH2 are values determined based on, for example, the average value of the pixel values of the division image PD. One of the first threshold value TH1 and the second threshold value TH2 may be set to a value larger than the average value, and the other may be set to a value smaller than the average value. In this way, by using two threshold values, the contamination region 87 can be detected and the verification region CA can be accurately determined regardless of whether the density of the contamination region 87 is higher or lower than the average value.

[0105] In the second embodiment, the division processing unit 93 generates the division image PD by dividing the verification image data PV by the second captured image P2. However, the division image PD may also be generated by dividing the first captured image P1 by the second captured image P2. Even in this case, by appropriately setting the threshold value, the contaminated area 87 can be detected and the verification area CA can be determined.

[0106] [Modification Example] Various modification examples related to the first and second embodiments will be described below.

[0107] In the first embodiment, as shown in FIG. 12, the verification area determination unit 85 determines the verification area CA so as to exclude the contaminated area 87 in the difference image PS. Therefore, the shape and size of the verification area CA determined by the verification area determination unit 85 vary. Instead, as shown in FIG. 26, the verification area determination unit 85 may divide the difference image PS into a plurality of blocks and determine one or more blocks that do not include the contaminated area 87 as the verification area CA. In the example shown in FIG. 26, the difference image PS is divided into four blocks B1 to B4. Since the contaminated area 87 is included in the block B4, the verification area determination unit 85 determines the blocks B1 to B3 other than the block B4 as the verification area CA. The same applies to the verification area determination unit in the second embodiment.

[0108] In the first embodiment, as shown in FIG. 4, the issuing device 10 prints only one verification image 43 on the admission ticket 40. Instead, as shown in FIG. 27, the issuing device 10 may print a plurality of verification images 43 on the admission ticket 40. In the example shown in FIG. 27, four verification images 43 are printed around the face image 42 on the admission ticket 40. In this case, the verification device 20 may detect the contaminated area 87 based on the difference image PS for each of the verification images 43 and determine the verification image 43 that does not include the contaminated area 87 as the verification area CA. The same applies to the second embodiment.

[0109] Also, in the first and second embodiments, the reference image 43 is a pattern image having a plurality of regions with different densities. However, the reference image 43 is not limited to this, and it may be any image such as an image having a geometric pattern or an image having micro characters. For example, as shown in FIG. 28, it is also possible to use a part of the face image 42 as the reference image 43.

[0110] Furthermore, the reference image 43 may be a plain (i.e., single color) image. Since unique density unevenness occurs each time the reference image 43, which is a plain image, is printed on the instant film 41, it is possible to perform collation between the first captured image P1 and the second captured image P2 based on this density unevenness.

[0111] Also, in the first and second embodiments, the reference image data PV is color image data. However, the reference image data PV may be achromatic image data. In this case, the gray-scale processing units 82, 83, 91, 92 are unnecessary.

[0112] Also, in the first and second embodiments, for the first captured image P1 and the second captured image P2, the authenticity of the admission ticket 40 is verified by comparing the spatial frequency characteristics as the information included in the collation area CA. The information used for the collation is not limited to the spatial frequency characteristics, and may be a pattern or characters included in the image.

[0113] Also, in the first and second embodiments, the printer 18 is an instant photo printer that uses the instant film 41 as a base material, but the printer 18 is not limited to an instant photo printer. The printer 18 may be, for example, a sublimation printer using a sublimation thermal transfer method. Also, the sublimation printer can use a plastic card as a base material instead of a dedicated coated paper. When using a sublimation printer, the admission ticket 40 may be created by printing the verification image 43 on a plastic card. Also, it is possible to use an inkjet printer of the inkjet method as the printer 18. The density characteristics of the images printed on the base material differ depending on the printing method. Therefore, even when used, it is possible to verify the authenticity of the forged admission ticket 40 by different printers with different printing methods.

[0114] Also, in the first and second embodiments, the information medium is the admission ticket 40 for the participant 13 to enter the event venue, but the information medium is not limited to the admission ticket 40. The information medium according to the technology of the present disclosure can also be applied to an ID card issued to a worker who performs short-term work. The ID card used by a worker working at a construction site or the like is likely to have dirt attached to the verification image 43 when held with a hand soiled with oil or mud during work. Therefore, the technology of the present disclosure is suitably used for verifying ID cards at construction sites and the like.

[0115] Also, in the first and second embodiments, the face image 42 is printed on the admission ticket 40, but the face image 42 does not necessarily have to be printed. That is, the information medium according to the technology of the present disclosure is also applicable to tickets and the like that do not require authentication of the owner of the information medium. For example, the information medium according to the technology of the present disclosure is also applicable to admission tickets, gift certificates, merchandise vouchers, or coupons where anti-counterfeiting is important.

[0116] In the first and second embodiments, for example, as the hardware structure of a processing unit that executes various processes such as the first imaging control unit 62, the second imaging control unit 63, and the printing control unit 64 of the issuing device 10, and the authenticity verification units 24 and 24A of the verification devices 20 and 20A, the following various processors can be used. In addition to CPUs 15A and 21A, which are general-purpose processors that execute software and function as various processing units, the various processors include a programmable logic device (PLD), which is a processor whose circuit configuration can be changed after manufacturing, such as an FPGA (Field Programmable Gate Array), and / or a dedicated electric circuit, which is a processor having a circuit configuration designed specifically to execute specific processes, such as an ASIC (Application Specific Integrated Circuit). A GPU (Graphics Processing Unit) may be used instead of the FPGA.

[0117] One processing unit may be composed of one of these various processors, or may be composed of a combination of two or more processors of the same type or different types (for example, a combination of multiple FPGAs, and / or a combination of a CPU and an FPGA or a combination of a CPU and a GPU). Also, a plurality of processing units may be composed of one processor.

[0118] As an example of configuring a plurality of processing units with a single processor, first, as represented by computers such as clients and servers, one processor is configured by a combination of one or more CPUs and software, and this processor functions as a plurality of processing units. Second, as represented by a System On Chip (SoC), etc., there is a form in which a processor that realizes the functions of an entire system including a plurality of processing units with a single IC (Integrated Circuit) chip is used. In this way, various processing units are configured as a hardware structure using one or more of the above various processors.

[0119] Furthermore, as a hardware structure of these various processors, more specifically, an electric circuit (Circuitry) combining circuit elements such as semiconductor elements can be used.

[0120] The technology of the present disclosure can also appropriately combine the above-described various embodiments and / or various modifications. Also, of course, various configurations can be adopted without being limited to the above embodiments as long as the gist is not deviated from. Furthermore, the technology of the present disclosure extends to a storage medium that non-temporarily stores a program in addition to the program.

[0121] The description content and the illustrated content shown above are detailed descriptions of the part related to the technology of the present disclosure and are only examples of the technology of the present disclosure. For example, the description regarding the above configuration, function, action, and effect is an example of the description regarding the configuration, function, action, and effect of the part related to the technology of the present disclosure. Therefore, it goes without saying that within the scope not departing from the gist of the technology of the present disclosure, unnecessary parts may be deleted, new elements may be added, or replacements may be made to the description content and the illustrated content shown above. Also, in order to avoid complication and facilitate the understanding of the part related to the technology of the present disclosure, the description regarding common technical knowledge etc. that does not particularly require explanation for implementing the technology of the present disclosure is omitted from the description content and the illustrated content shown above.

[0122] As used herein, "A and / or B" is synonymous with "at least one of A and B". That is, "A and / or B" means that it may be only A, only B, or a combination of A and B. Further, in this specification, when expressing three or more matters connected by "and / or", the same concept as that of "A and / or B" is applied.

[0123] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. An authenticity verification system comprising an issuing device that issues an information medium by printing a verification image on a base material based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image, wherein the issuing device includes a first processor, the first processor acquires, as a first captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium, the verification device includes a second processor, the second processor acquires, as a second captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium to be verified, generates a corrected image obtained by performing density correction on the first captured image by predicting a density change at the time when the second captured image is acquired based on the elapsed time from the time when the first captured image is acquired, determines a verification region for verifying the first captured image and the second captured image based on a difference image obtained by taking a difference between the second captured image and the corrected image for each pixel, An authenticity verification system.

2. the first processor registers the first captured image in a storage device, and the second processor acquires the first captured image registered in the storage device, and the second processor performs the density correction based on the elapsed time from the time when the first captured image is registered in the storage device, The authenticity verification system according to claim 1.

3. the second processor determines, as the verification region, a region where the absolute value of the pixel value of the difference image is equal to or less than a threshold value, The authenticity verification system according to claim 1 or claim 2.

4. the second processor performs the density correction based on a table representing the relationship between the elapsed time and the density change, The authenticity verification system according to any one of claims 1 to 3.

5. the second processor verifies the authenticity of the information medium by comparing the information included in the verification region for the first captured image and the second captured image, The authenticity verification system according to any one of claims 1 to 4.

6. the information is spatial frequency characteristics, The authenticity verification system according to claim 5.

7. An authenticity verification method using an issuing device that issues an information medium by printing a verification image on a base material based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image, comprising: A first captured image acquisition step of acquiring, as a first captured image, an image obtained by imaging the verification image printed on the information medium with a camera, executed by the issuing device, a second captured image acquisition step of acquiring, as a second captured image, an image obtained by imaging the verification image printed on the information medium to be verified with a camera, a density correction step of generating a corrected image obtained by performing density correction on the first captured image by predicting a density change at the time when the second captured image was acquired based on the elapsed time from the time when the first captured image was acquired, a verification area determination step of determining a verification area for verifying the first captured image and the second captured image based on a difference image obtained by taking a difference between the second captured image and the corrected image for each pixel, executed by the verification device, authenticity verification method.

8. An authenticity verification system comprising an issuing device that issues an information medium by printing a verification image on a base material based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image, the issuing device includes a first processor, the first processor, acquires, as a first captured image, an image obtained by imaging the verification image printed on the information medium with a camera, the verification device includes a second processor, the second processor, acquires, as a second captured image, an image obtained by imaging the verification image printed on the information medium to be verified with a camera, and determines a verification area for verifying the first captured image and the second captured image based on a division image obtained by dividing the second captured image and the verification image data for each pixel, authenticity verification system.

9. The second processor determines, as the verification area, an area where the pixel value of the division image is equal to or less than a threshold value, The authenticity verification system according to Claim 8.

10. The second processor verifies the authenticity of the information medium by comparing the information included in the verification area for the first captured image and the second captured image, The authenticity verification system according to claim 8 or claim 9.

11. The information is spatial frequency characteristics, The authenticity verification system according to claim 10.

12. An authenticity verification method using an issuing device that issues an information medium by printing a verification image on a substrate based on verification image data, and a verification device that verifies the authenticity of the information medium based on the verification image, A first captured image acquisition step of acquiring, as a first captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium, Causing the issuing device to execute, A second captured image acquisition step of acquiring, as a second captured image, an image obtained by capturing, with a camera, the verification image printed on the information medium to be verified, A verification region determination step of determining a verification region for verifying the first captured image and the second captured image based on a division image obtained by dividing the second captured image and the verification image data pixel by pixel, Causing the verification device to execute, Authenticity verification method.

Images