Authenticity determination device, computer program, and authenticity determination method

Abstract

To provide an authenticity determination device, a computer program, and an authenticity determination method, capable of detecting clear diffraction light and determining authenticity of a medium.SOLUTION: An authenticity determination device comprises a light emitting unit, a transmission restriction unit that restricts transmission of light emitted by the light emitting unit, and a control unit. The control unit obtains a first image capturing a target medium by irradiating the target medium with transmission light restricted by the transmission restriction unit, specifies code information expressed by a hologram on the basis of the obtained first image, and determines authenticity of the target medium on the basis of the specified code information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an authenticity determining device, a computer program, and an authenticity determining method. [Background technology]

[0002] Credit cards, paper money, stock certificates, gift certificates, luxury brand goods, etc. use media on which information is recorded to prevent duplication and counterfeiting. Such media utilize security technologies such as holograms, which are difficult to duplicate.

[0003] Patent Document 1 discloses an inspection device that illuminates a hologram on a banknote with light from a light source, captures the light reflected from the hologram in two different directions into a reflective prism, and refracts it in approximately the same direction, making it possible to visually recognize two images of the hologram. However, operating an inspection device such as that disclosed in Patent Document 1 requires special skills and expertise.

[0004] On the other hand, mobile devices such as smartphones equipped with flashlights, high-performance cameras capable of taking high-resolution photographs, and advanced image processing functions are widely in use, and it is reasonable to determine the authenticity of media by using the functions of such mobile devices without the need for special skills or expertise. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-350995 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the light-emitting elements used in flashlights mounted on mobile devices such as smartphones are small surface light sources, and therefore have a larger light-emitting surface than ideal point light sources. Light emitted from a surface light source contains diffracted light. If diffracted light caused by this diffracted light is observed at the same time, there is a problem that the diffracted light cannot be obtained as clearly as in the case of a point light source.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide an authenticity determining device, a computer program, and an authenticity determining method that can detect clear diffracted light and determine the authenticity of a medium. [Means for solving the problem]

[0008] The authenticity determination device of this embodiment includes a light emitting unit, a transmission limiting unit that limits the transmission of light emitted from the light emitting unit, and a control unit, and the control unit irradiates a target medium with the transmitted light limited by the transmission limiting unit to obtain a first image of the target medium, identifies code information represented by a hologram based on the obtained first image, and determines the authenticity of the target medium based on the identified code information.

[0009] The computer program of this embodiment causes a computer to execute a process of acquiring a first image of a target medium by irradiating the target medium with light whose transmission is limited by a transmission limiting unit that limits the transmission of light emitted from a light emitting unit, identifying code information represented by a hologram based on the acquired first image, and determining the authenticity of the target medium based on the identified code information.

[0010] The authenticity determination method of this embodiment involves irradiating a target medium with light whose transmission is limited by a transmission limiting section that limits the transmission of light emitted from a light emitting section, obtaining a first image of the target medium, identifying code information represented by a hologram based on the obtained first image, and determining the authenticity of the target medium based on the identified code information. Effect of the Invention

[0011] According to the present invention, it is possible to detect clear diffracted light and determine the authenticity of a medium. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an authenticity determining device. [Diagram 2] FIG. 4 is a diagram illustrating an example of a transmission limiting portion. [Diagram 3] FIG. 1 is a plan view showing an example of a schematic hologram structure; [Figure 4] FIG. 4 is a vertical cross-sectional view taken along line AA in FIG. [Diagram 5] 11 is a diagram showing an example of diffracted light appearing around the zeroth-order diffracted light in the case where there is no transmission limiting portion. FIG. [Figure 6] 11 is a diagram showing an example of diffracted light appearing around the zeroth-order diffracted light when a transmission limiting portion is present; FIG. [Figure 7] FIG. 1 is a diagram showing an example of normal diffracted light due to ambient light. [Figure 8] FIG. 13 is a diagram showing an example of photographing a target medium that is a counterfeit. [Figure 9] 1A to 1C are diagrams illustrating a first example of characteristics of a special diffracted light pattern according to the present embodiment. [Figure 10] FIG. 11 is a diagram showing a second example of the characteristics of a special diffracted light pattern according to the present embodiment. [Figure 11] FIG. 13 is a diagram showing an example of authenticity determination using a special diffracted light pattern. [Figure 12] FIG. 13 is a diagram showing an example of authenticity determination using a normal diffracted light pattern. [Figure 13] FIG. 13 is a diagram showing an example of a display screen when authenticity is determined. [Figure 14] 3 is a diagram showing an example of a procedure of an authenticity determining process performed by the authenticity determining device of the present embodiment. FIG. [Figure 15] FIG. 1 is a diagram illustrating an example of a configuration of an authenticity determination system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (First embodiment) Hereinafter, the present invention will be described with reference to the drawings showing the embodiments. FIG. 1 is a diagram showing an example of the configuration of an authenticity determination device 50. The authenticity determination device 50 includes a control unit 51 that controls the entire device, a light emitting unit 52, a transmission limiting unit 53, an imaging unit 54, a display unit 55, an operation unit 56, a communication unit 57, a memory 58, and a storage unit 59. The authenticity determination device 50 is composed of a mobile device such as a smartphone, a tablet terminal, or a personal computer, and is carried by a user. In this embodiment, the authenticity determination device 50 will be described by taking a smartphone as an example.

[0014] The storage unit 59 can be configured with a semiconductor memory or the like, and can store a computer program 60, correct answer information 61, and required information. The computer program 60 is an authenticity determination application (also simply referred to as an "app"), and runs on the authenticity determination device 50. The correct answer information 61 includes a correct answer character string and a correct answer image, which will be described later.

[0015] The control unit 51 is configured by incorporating a required number of CPUs (Central Processing Units), MPUs (Micro-Processing Units), GPUs (Graphics Processing Units), etc. The control unit 51 can execute processing defined by a computer program 60. In other words, the processing by the control unit 51 is also processing by the computer program 60. A recording medium (a non-transitory recording medium readable by a computer) M on which the computer program 60 is recorded may be read by a recording medium reading device (such as a computer) 40, and the read computer program 60 may be downloaded via a communication unit 57 and stored in a storage unit 59.

[0016] The light emitting unit 52 includes a light emitting element such as an LED. The light emitting element is a small surface light source. A white LED or the like can be used as the LED. The light emitting unit 52 irradiates the target medium with reference light. The target medium is an object to be judged for authenticity, and is a medium on which information is recorded to prevent copying, counterfeiting, etc., such as credit cards, banknotes, stock certificates, gift certificates, and luxury brand goods. In this embodiment, the target medium uses holography (hologram).

[0017] Holography is a technology in which the amplitude and phase of the light wave to be recorded (object light) is made to interfere with a reference light, recording it on a medium as an interference pattern, and then reproducing the recorded light wave using the diffraction phenomenon. The recorded interference pattern is called a hologram.

[0018] The transmission limiting section 53 has a function of converting the light emitted from the surface light source into light emitted from a point light source by controlling the shape of the light emitted from the light emitting section 52 (i.e., the light emitted from the surface light source). That is, the transmission limiting section 53 limits the transmission of the light emitted from the light emitting section 52. Specifically, the transmission limiting section 53 transmits light by restricting it to an area (like a pinhole) smaller than the light emitting surface of the light emitting section 52. The transmission limiting section 53 will be described in detail later. The transmission limiting section 53 is also called a light emission shape control section.

[0019] The imaging unit 54 includes a camera. The imaging unit 54 can acquire an image of the target medium. Specifically, the imaging unit 54 acquires an image (first image) of the target medium under a condition where the light from the light-emitting unit 52 is irradiated onto the target medium (also referred to as "LED on"), and acquires an image (second image) of the target medium under a condition where the light from the light-emitting unit 52 is not irradiated onto the target medium (also referred to as "LED off").

[0020] The display unit 55 includes a liquid crystal display panel, an organic EL display panel, or the like, and is capable of displaying the determination results obtained by the authenticity determination device 50, and the like.

[0021] The operation unit 56 is configured with a touch panel or the like, and allows a character input operation on the display unit 55 as well as an operation on icons, images, characters, etc. displayed on the display unit 55.

[0022] The communication unit 57 includes a communication module and has a function of communicating with an external device via a communication network.

[0023] The memory 58 can be composed of a semiconductor memory such as a static random access memory (SRAM), a dynamic random access memory (DRAM), a flash memory, etc. By expanding the computer program 60 in the memory 58, the control unit 51 can execute the computer program 60.

[0024] The control unit 51 (computer program 60, authenticity determination application) can control the on / off of the light emission of the light emitting unit 52, control the amount of light, and control the operation of the imaging unit 54. The control unit 51 also performs image processing on the acquired image, authenticity determination of the target medium, and other processes.

[0025] FIG. 2 is a diagram showing an example of the transmission limiting unit 53. A removable cover 30 is attached to the back side of the smartphone, which is the authenticity determination device 50. The cover 30 is provided with a transmission limiting unit 53 at a position corresponding to the flashlight of the light-emitting unit 52. The transmission limiting unit 53 has a slidable shielding plate, and when the changeover switch is slid to one side, the shielding plate is opened, and the light of the flashlight of the light-emitting unit 52 is in a full-light state, and it can be used as a normal flashlight (see FIG. 2A). When the changeover switch is slid to the other side, the transmission of the light of the flashlight of the light-emitting unit 52 is restricted by a pinhole formed in the shielding plate, and it can be used for authenticity determination (see FIG. 2B). In the state of FIG. 2B, only the light emitted from the light-emitting unit 52 that has passed through the pinhole is irradiated onto the target medium, so that it is irradiated as if it were light emitted from a point light source. The diameter of the pinhole formed in the transmission limiting unit 53 is preferably 0.1 mm or more and 1.0 mm or less. If the hole is smaller than 0.1 mm, the amount of light passing through the hole is small, and the amount of light that constitutes the diffracted light from the target medium is also small. Also, if the hole is larger than 1.0 mm, the influence of light that wanders around from places other than the center of the light source becomes large. For these reasons, it becomes difficult to obtain an optical image such as a diffraction pattern that is desired to be obtained from the target medium.

[0026] The configuration of the transmission limiting portion 53 is not limited to a pinhole formed in the shielding plate. Liquid crystal may be used as the transmission limiting portion 53. In liquid crystal, molecules easily move in response to voltage or magnetic force, changing the way light passes through. By utilizing this property, an electrically controllable light shutter can be configured. That is, by electrically controlling the liquid crystal, it is possible to control the entire liquid crystal so that it can transmit light, and also to control only one image or a few pixels (pixels, dots) of the liquid crystal, which corresponds to a pinhole, so that light can pass through.

[0027] By using the transmission limiting section 53, the spot of the zeroth-order diffracted light (total reflection) by the light transmitted through the transmission limiting section 53 becomes smaller, and the irradiation pattern of the light irradiated on the target medium becomes closer to the light irradiated from the center of the spot, and approaches the light irradiated from a point light source. The zeroth-order diffracted light is the total reflection light in a state where all of the RGB color components are irradiated with a luminous intensity equal to or higher than the upper limit of detection of the camera sensor (saturation state or a state close to saturation state), and is a strong white bright spot. The zeroth-order diffracted light is, for example, a circular or rectangular shape, and is an area where continuous bright spots are gathered.

[0028] Next, a hologram structure provided on a target medium that is the target of the authenticity determination device 50 of this embodiment will be described.

[0029] FIG. 3 is a plan view showing an example of a schematic of the hologram structure 10, and FIG. 4 is a vertical cross-sectional view taken along the line AA in FIG. 3. The hologram structure 10 has a hologram layer 1 having a hologram formation region 11. In the hologram formation region 11, a phase-type Fourier transform hologram that converts light incident from a light-emitting unit 52 into a desired optical image is recorded. The hologram formation region 11 is a reflection-type Fourier transform hologram formation region, and the hologram structure 10 has a deposition layer 2 formed so as to be in contact with the uneven surface 12 of the hologram formation region 11. In the hologram structure 10, a transparent substrate 3 is laminated on the surface of the hologram layer 1 opposite to the deposition layer 2. In FIG. 3, the region surrounded by a dashed line is the hologram formation region 11.

[0030] Here, the term "recording a phase-type Fourier transform hologram" means that the phase information of the Fourier transform image obtained through the Fourier transform of the original image is multi-valued and recorded as depth. Therefore, an uneven surface 12 is formed in the hologram formation region 11 of the hologram layer 1 where the phase-type Fourier transform hologram is recorded.

[0031] As described above, since the phase-type Fourier transform hologram is recorded in the hologram formation region 11, the hologram structure 10 can reproduce an optical image (also called "special diffracted light pattern" or "code information") in the hologram formation region in a planar view by the light incident from the light emitting unit 52. That is, the optical image can be reproduced only when the hologram structure 10 is irradiated with light from the light emitting unit 52, and the optical image is not reproduced when the hologram structure 10 is not irradiated with light from the light emitting unit 52. The optical image is such that the original digital information can be extracted from the shape represented by a pattern or picture, etc., using the authenticity determination device 50, and includes two-dimensional codes such as barcodes and QR codes (registered trademark), two-dimensional barcodes (code information), etc. Details of the above-mentioned hologram structure are disclosed in Japanese Patent No. 6973550, which is a patent application filed by the applicant. Details of matters relating to phase-type Fourier transform holograms and the like are disclosed in the applicant's patent applications Nos. 4780319, 6037103, 6686322, 6686323, 6759600, 6743465, 6915346, and 7190113.

[0032] Next, a method for determining the authenticity of a target medium will be described. A user can obtain the authenticity determination result of a target medium by simply performing a simple operation using the authenticity determination device 50, and no special skills or expertise are required. The user first starts an authenticity determination application (app). The transmission limiting unit 53 functions so that the light from the light emitting unit 52 approaches the light from a point light source. The user points the light emitting unit 52 and the imaging unit 54 of the smartphone, which is the authenticity determination device 50, toward the target medium. The authenticity determination application obtains an image (first image) of the target medium by irradiating the target medium with light from the light emitting unit 52 and also obtains an image (second image) of the target medium without irradiating the target medium with light from the light emitting unit 52. The authenticity determination application performs authenticity determination of the target medium based on the obtained images (first image and second image) and outputs the determination result. In this way, the user can perform authenticity determination by simply holding the smartphone toward the target medium. The authenticity determination application can repeat the process of acquiring the images (first image and second image) and the process of determining authenticity as necessary. A specific example of authenticity determination will be described below.

[0033] First, a case where the transmission limiting section 53 is not provided or where the transmission limiting section 53 is not functioning will be described.

[0034] FIG. 5 is a diagram showing an example of diffracted light appearing around the zeroth-order diffracted light when there is no transmission limiting section 53. In the example of FIG. 5, it is assumed that the target medium is genuine and is irradiated with light from the light emitting section 52 (LED on). Since the LED is on, in addition to the ambient light, the light from the light emitting section 52 is irradiated as the reference light onto the target medium. When the light emitting section 52 is irradiated as the reference light onto the genuine target medium, a special diffracted light pattern (unique bright spot pattern) is reproduced around the zeroth-order diffracted light (total reflection). In the judgment area, a first hologram is recorded so that the special diffracted light pattern (unique bright spot pattern) is reproduced by the light from the light emitting section 52. The special diffracted light pattern is the diffracted light of the first hologram. However, since there is no transmission limiting section 53, the light from the light emitting section 52 is not light from a light source that can be regarded as a point light source, so the spot of the zeroth-order diffracted light (reflected light) is large and the special diffracted light pattern is highly blurred. This may cause problems in reading the special diffracted light pattern.

[0035] FIG. 6 is a diagram showing an example of diffracted light appearing around the zeroth-order diffracted light when the transmission limiting section 53 is present. In the example of FIG. 6, it is assumed that the target medium is genuine and is irradiated with light from the light emitting section 52 (LED on). Since the LED is on, the target medium is irradiated with light from the light emitting section 52 as reference light in addition to ambient light. When light is irradiated from the light emitting section 52 as reference light, the genuine target medium reproduces a special diffracted light pattern (unique bright spot pattern) around the zeroth-order diffracted light (total reflection). In the judgment area, a first hologram is recorded so that the special diffracted light pattern (unique bright spot pattern) is reproduced by the light from the light emitting section 52. In the example of FIG. 6, the transmission limiting section 53 is present and the function of the transmission limiting section 53 is used, so that the light from the light emitting section 52 approaches light from a point light source, the spot of the zeroth-order diffracted light (reflected light) is small, and the special diffracted light pattern is clear. This makes it easier to read the special diffracted light pattern.

[0036] FIG. 7 is a diagram showing an example of normal diffracted light due to ambient light. In the example of FIG. 7, it is assumed that the target medium is genuine and that light from the light-emitting unit 52 is not being irradiated (LED off). Because the LED is off, only ambient light is irradiated onto the target medium as reference light. When ambient light is irradiated onto a genuine target medium as reference light, it reproduces a normal diffracted light pattern (in the example shown in the figure, a tiara pattern). A second hologram is recorded in the judgment area so that normal diffracted light is reproduced by ambient light. The normal diffracted light pattern is the diffracted light of the second hologram.

[0037] FIG. 8 is a diagram showing an example of photographing a target medium when it is a counterfeit. When the target medium is a counterfeit (such as a forged print), no hologram is present in the judgment area of ​​the target medium. FIG. 8A shows a case where the target medium is photographed with no light emitted from the light-emitting unit 52 of the smartphone, which is the authenticity judgment device 50 (the LED is off). Because the LED is off, only ambient light is irradiated onto the target medium as reference light, and the reflected light returns to the imaging unit 54 (camera). Because no hologram is present in the judgment area, the usual diffracted light pattern described above is not seen.

[0038] FIG. 8B shows a case where the target medium is photographed with light irradiated from the light-emitting unit 52 of the smartphone (LED is on). Because the LED is on, the target medium is irradiated with light from the light-emitting unit 52 as reference light in addition to ambient light. In this case, a bright spot caused by the light from the light-emitting unit 52 is detected in the judgment area, and the specularly reflected light of that light returns to the imaging unit 54 (camera). Because no hologram exists in the judgment area, the special diffracted light pattern described above is not seen.

[0039] As described above, in a genuine target medium, a special diffracted light pattern and a normal diffracted light pattern are reproduced depending on the shooting conditions (LED on / off), whereas in a counterfeit target medium, neither the special diffracted light pattern nor the normal diffracted light pattern is reproduced, making it easy to determine the authenticity of the target medium.

[0040] On the other hand, it is also possible that there may be a third party who obtains a copy of the special diffracted light pattern (code information such as a two-dimensional code or a two-dimensional barcode) shown in Figure 6 and makes a counterfeit product appear to be the real thing. Below, we will explain how to deal with such fraud.

[0041] FIG. 9 is a diagram showing a first example of the characteristics of the special diffracted light pattern of this embodiment. FIG. 9A and FIG. 9B show a case where an image is taken in a state where the light emitting unit 52 is not emitting light, that is, the LED is off. As shown in FIG. 9A, a normal diffracted light pattern (in the example shown in the figure, a tiara pattern) is reproduced in the judgment area. As shown in FIG. 9B, even if the smartphone is moved in the direction of the arrow (horizontally) relative to the judgment area, the position of the normal diffracted light pattern reproduced in the judgment area does not change. The normal diffracted light pattern has such characteristics.

[0042] On the other hand, FIG. 9C and FIG. 9D show a state where the light emitting unit 52 is made to emit light (more specifically, a state where the light from the light emitting unit 52 is converted by the transmission limiting unit 53 into light from a point light source), that is, a case where an image is taken with the LED turned on. As shown in FIG. 9C, a special diffracted light pattern (as shown in the figure, code information such as a two-dimensional code or a two-dimensional barcode around the zeroth-order diffracted light) is reproduced in the judgment area. As shown in FIG. 9D, when the smartphone is moved in the direction of the arrow relative to the judgment area, the position of the special diffracted light pattern in the judgment area moves following the positions of the light emitting unit 52 and the imaging unit 54 together with the zeroth-order diffracted light. This is because the incident point of the light entering the judgment area moves.

[0043] When the user points the light-emitting unit 52 and the imaging unit 54 of the smartphone, which is the authenticity determination device 50, at the target medium, the control unit 51 (authenticity determination application) can guide (by outputting audio or displaying a guide message, for example) the user to move the smartphone horizontally relative to the target medium. The control unit 51 (authenticity determination application) can determine the authenticity of the target medium by photographing the target medium with the light-emitting unit 52 emitting light while the user moves the smartphone.

[0044] As described above, in this embodiment, when the position of the smartphone (the positions of the light-emitting unit 52 and the imaging unit 54) is moved horizontally relative to the target medium, the position of the zeroth-order diffracted light and the position of the special diffracted light pattern move in unison. Therefore, when a copy of the special diffracted light pattern is simply displayed, the displayed copy of the special diffracted light pattern does not move, and the authenticity of the target medium can be accurately determined.

[0045] FIG. 10 is a diagram showing a second example of the characteristics of the special diffracted light pattern of this embodiment. FIG. 10 shows a state where the light emitting unit 52 is emitting light (more specifically, a state where the light from the light emitting unit 52 is converted by the transmission limiting unit 53 into light from a point light source), that is, a case where an image is taken with the LED turned on. As shown in FIG. 10, the distance between the target medium and the smartphone is changed to H1, H2 (>H1), and H3 (>H2). The larger the distance between the target medium and the smartphone, the larger the size of the special diffracted light pattern around the 0th order diffracted light.

[0046] When the user points the light-emitting unit 52 and the image capturing unit 54 of the smartphone, which is the authenticity determining device 50, toward the target medium, the control unit 51 (authenticity determination application) can provide guidance (such as audio output or display of a guidance message) to move the smartphone closer to the target medium. The control unit 51 (authenticity determination application) can determine the authenticity of the target medium by photographing the target medium with the light-emitting unit 52 emitting light while the user moves the smartphone.

[0047] As described above, in this embodiment, when the position of the smartphone (the position of the light-emitting unit 52 and the imaging unit 54) is moved so that the distance from the target medium becomes longer or shorter, the size of the special diffraction light pattern around the zeroth order diffraction light changes. Therefore, when a copy of the special diffraction light pattern is simply displayed, the size of the displayed copy of the special diffraction light pattern does not change, so the authenticity of the target medium can be determined with high accuracy.

[0048] Next, we will explain the details of authenticity determination using a special diffracted light pattern (when the LED is on) and a normal diffracted light pattern.

[0049] FIG. 11 is a diagram showing an example of authenticity determination using a special diffracted light pattern. Each process shown in FIG. 11 is performed by the control unit 51 (authenticity determination application). The control unit 51 obtains a captured image (first image) of a target medium by irradiating the target medium with transmitted light, which is limited by the transmission limiting unit 53, and performs a filter process on the obtained captured image, thereby identifying an area with a predetermined luminous intensity or higher as a bright spot area. In the filter process shown in FIG. 11, a process is performed to leave only strong white bright spots that are saturated or close to saturation among the bright spots in the captured image, thereby identifying a white bright spot area.

[0050] The control unit 51 performs a zeroth-order diffracted light detection process on the white bright spot region to detect the zeroth-order diffracted light coordinates. The zeroth-order diffracted light detection process includes (1) a process of determining a strong white bright spot where all of the RGB color components are saturated or close to being saturated, (2) a process of calculating the shape and area of ​​the zeroth-order diffracted light based on the number of pixels in a region where pixels of saturated bright spots or close to being saturated are consecutive, and (3) a process of calculating the coordinates of the center point.

[0051] The control unit 51 performs a process of detecting the bright spot pattern. Specifically, the control unit 51 detects the bright spot pattern in the peripheral area of ​​the zeroth-order diffracted light. The brightness of the bright spot pattern is lower than that of the zeroth-order diffracted light, but is stronger than a normal diffracted light pattern, so it is sufficient to detect bright spots within a predetermined brightness value range. In the example of FIG. 11, a special diffracted light pattern including code information such as a two-dimensional code or a two-dimensional barcode is detected (identified). That is, the control unit 51 can identify the bright spot area based on the acquired first image, and identify code information represented by a hologram in the peripheral area of ​​the identified bright spot area.

[0052] The control unit 51 performs character reading processing on the identified code information to convert the code information into a character string. In the example of Fig. 11, a URL is given as an example of a character string, but the character string is not limited to a URL.

[0053] The control unit 51 performs a string matching process to determine whether the converted string matches any of the multiple correct strings included in the correct answer information 61, and outputs the string matching result. If a predetermined threshold value (e.g., 90%) or more of the characters in the converted string match the characters in the correct answer string, the strings can be determined to match.

[0054] That is, the control unit 51 can convert the code information into a character string and compare the converted character string with the correct character string to determine the authenticity of the target medium. The control unit 51 can also determine the authenticity of the target medium based on whether the number of characters that match between the converted character string and the correct character string is equal to or greater than a predetermined threshold.

[0055] The control unit 51 performs an authenticity determination process and outputs a first authenticity determination result based on the string matching result. The first authenticity determination result can be determined to be "genuine" when the string matching result is "match", and determined to be "fake" when the string matching result is "mismatch".

[0056] As described above, the control unit 51 can identify the code information represented by the hologram based on the acquired first image, and determine the authenticity of the target medium based on the identified code information. As described above, the control unit 51 uses a captured image (first image) obtained by irradiating the target medium with light from a light source that can be regarded as a point light source as reference light, and therefore can detect clear diffracted light to determine the authenticity of the medium.

[0057] Fig. 12 is a diagram showing an example of authenticity determination using a normal diffracted light pattern. Each process shown in Fig. 12 is performed by the control unit 51 (authenticity determination application). The control unit 51 acquires a captured image (second image) of the target medium without irradiating the target medium with transmitted light restricted by the transmission restriction unit 53, which is light from the light emitting unit 52, and performs a diffracted light pattern detection process on the acquired captured image to detect (identify) a normal diffracted light pattern.

[0058] The control unit 51 performs a similarity calculation process to calculate the similarity between the detected normal diffracted light pattern and one or more correct images included in the correct answer information 61. The calculation of the similarity can use the following template matching method. That is, the mean square error of the luminance value for each pixel corresponding between the detected normal diffracted light pattern and the correct answer image is calculated, the mean square error calculated for each pixel is added, and the reciprocal of the sum is set as the similarity. In this case, the similarity is a value equivalent to the reciprocal of the value calculated based on the mean square error, so that the larger the similarity, the more similar the normal diffracted light pattern and the correct answer image are. The calculation of the similarity is not limited to the template matching method.

[0059] The control unit 51 performs an authenticity determination process and outputs a second authenticity determination result based on the calculated similarity. The second authenticity determination result can be determined to be "genuine" if the calculated similarity is equal to or greater than a predetermined similarity threshold, and can be determined to be "fake" if the calculated similarity is less than the similarity threshold.

[0060] As described above, the control unit 51 can acquire a second image of the target medium without irradiating the target medium with the transmitted light restricted by the transmission restriction unit 53, identify a hologram image (normal diffracted light pattern) represented by a hologram based on the acquired second image, and determine the authenticity of the target medium based on the identified hologram image. The control unit 51 can also calculate the similarity between the identified hologram image and a correct image, and determine the authenticity of the target medium based on the calculated similarity and a similarity threshold.

[0061] The control unit 51 can determine the target medium as genuine when the first authenticity determination based on the code information and the second authenticity determination based on the hologram image are both determined to be genuine. As a result, even if either the code information or the hologram image is illegally obtained by a third party, the other of the code information or the hologram image has not been illegally obtained, so that by employing both the first authenticity determination based on the code information and the second authenticity determination based on the hologram image, a situation in which a counterfeit is determined to be genuine can be prevented.

[0062] FIG. 13 is a diagram showing an example of a display screen during authenticity determination. The display screen shown in FIG. 13 is displayed on the display unit 55. FIG. 13A shows a display screen when the target medium is determined to be genuine in the authenticity determination, and FIG. 13B shows a display screen when the target medium is determined to be a counterfeit. When a user starts the authenticity determination application, the control unit 51 acquires a first image obtained by photographing the target medium with the LED on, and performs a first authenticity determination process by identifying code information (special diffracted light pattern) represented by a hologram based on the acquired first image, and acquires a second image obtained by photographing the target medium with the LED off, and performs a second authenticity determination process by identifying a hologram image (normal diffracted light pattern) represented by a hologram based on the acquired second image. The first authenticity determination process and the second authenticity determination process can be repeated a predetermined number of times until an authenticity determination result is obtained. 13A , when control unit 51 detects code information through the first authenticity determination process, it displays the code information on display unit 55, and thereafter, when a hologram image is detected through the second authenticity determination process, it displays the hologram image on display unit 55. When it is determined that the target medium is genuine through both the first authenticity determination based on the code information and the second authenticity determination based on the hologram image, it is possible to notify the user that the target object is genuine by displaying a message such as “Hologram recognized.”

[0063] On the other hand, as shown in FIG. 13B, if the target medium is determined to be a fake by both the first authenticity determination based on the code information and the second authenticity determination based on the hologram image, a message such as "Timeout has occurred" can be displayed to notify the user that the target medium is a fake.

[0064] Fig. 14 is a diagram showing an example of the procedure of the authenticity determination process by the authenticity determination device 50 of this embodiment. The control unit 51 starts an application (authenticity determination application) (S11) and checks the function of the transmission limiting unit 53 (S12). The function of the transmission limiting unit 53 is checked by checking whether or not the changeover switch for the transmission limiting unit 53 is switched to a state in which the transmission of light from the flashlight of the light emitting unit 52 is restricted by a pinhole formed in the shielding plate (see Fig. 2). The control unit 51 may output a guide to the user to change the changeover switch depending on the check result.

[0065] The control unit 51 acquires an image (first image) of the target medium with the LED on (S13), and performs filtering on the acquired image to detect the position of the zeroth-order diffracted light (S14). The control unit 51 identifies code information (special diffracted light pattern) in the area surrounding the zeroth-order diffracted light (S15), and converts the identified code information into a character string (S16). The control unit 51 compares the converted character string with the correct character string to perform a first authenticity determination (S17).

[0066] The control unit 51 acquires an image (second image) of the target medium taken under the condition of LED off (S18), identifies a normal diffracted light pattern based on the acquired image (S19), and calculates a similarity between the identified normal diffracted light pattern and the correct image (S20). The control unit 51 performs a second authenticity determination based on the calculated similarity (S21).

[0067] The control unit 51 can repeat the processes of steps S13 to S17 a required number of times until a first authenticity determination result is obtained. The control unit 51 can also repeat the processes of steps S18 to S21 a required number of times until a second authenticity determination result is obtained. The control unit 51 determines the authenticity of the target medium based on the first and second authenticity determination results (S22). The control unit 51 outputs the authenticity determination result (S23) and ends the process.

[0068] Second embodiment In the first embodiment described above, the authenticity determination device 50, such as a smartphone, is configured to perform the authenticity determination by itself, but the present invention is not limited to this. In the second embodiment, a case will be described in which the terminal device that photographs the target medium and the authenticity determination device that performs the authenticity determination are separate devices.

[0069] 15 is a diagram showing an example of the configuration of an authenticity determination system. The authenticity determination system includes a terminal device 100 and an authenticity determination device 150. The terminal device 100 and the authenticity determination device 150 are connected via a communication network N.

[0070] The terminal device 100 can be configured with a smartphone, a tablet terminal, a PC, etc. The terminal device 100 includes a control unit 101 that controls the entire device, a light emitting unit 102, a transmission limiting unit 103, an imaging unit 104, a display unit 105, an operation unit 106, a communication unit 107, a memory 108, and a storage unit 109. The control unit 101, the light emitting unit 102, the transmission limiting unit 103, the imaging unit 104, the display unit 105, the operation unit 106, the communication unit 107, the memory 108, and the storage unit 109 have the same functions as the control unit 51, the light emitting unit 52, the transmission limiting unit 53, the imaging unit 54, the display unit 55, the operation unit 56, the communication unit 57, the memory 58, and the storage unit 59 illustrated in FIG. 1, respectively, and therefore description thereof will be omitted.

[0071] The computer program 110 is obtained by removing the process related to authenticity determination from the computer program 60 illustrated in Fig. 1. Also, the computer program 110 differs from the configuration in Fig. 1 in that the storage unit 109 does not store the correct answer information 61.

[0072] The authenticity determination device 150 can be realized by a server or a cloud. The authenticity determination device 150 includes a control unit 151 that controls the entire device, a communication unit 152, a memory 153, and a storage unit 154. The control unit 151, the communication unit 152, the memory 153, and the storage unit 154 have the same functions as the control unit 51, the communication unit 57, the memory 58, and the storage unit 59 illustrated in Fig. 1, respectively, and therefore description thereof will be omitted.

[0073] The computer program 160 includes a process related to authenticity determination among the computer programs 60 illustrated in Fig. 1. The correct answer information 161 is similar to the correct answer information 61 illustrated in Fig. 1.

[0074] The first embodiment and the second embodiment differ in that the first image and the second image captured by the terminal device 100 are transmitted to the authenticity determination device 150, the authenticity determination device 150 acquires the first image and the second image captured by the terminal device 100 from the terminal device 100, and the authenticity determination device 150 transmits the authenticity determination result to the terminal device 100. The authenticity determination by the authenticity determination device 150 is similar to that in the first embodiment, and therefore a description thereof will be omitted.

[0075] According to each of the above-described embodiments, by using a common device (equipment) such as a smartphone, it is possible to easily determine the authenticity of the target medium by utilizing clear diffracted light from a light source that can be regarded as a point light source, without requiring any special skills.

[0076] (Additional Note 1) The authenticity determination device includes a light emitting unit, a transmission limiting unit that limits the transmission of light emitted from the light emitting unit, and a control unit, wherein the control unit irradiates a target medium with the transmitted light limited by the transmission limiting unit to obtain a first image of the target medium, identifies code information represented by a hologram based on the obtained first image, and determines the authenticity of the target medium based on the identified code information.

[0077] (Supplementary Note 2) In the authenticity determination device of Supplementary Note 1, the control unit identifies a bright spot area based on the acquired first image, and identifies code information represented by a hologram in a peripheral area of ​​the identified bright spot area.

[0078] (Supplementary Note 3) In the authenticity determining device according to Supplementary Note 1 or Supplementary Note 2, the transmission limiting section transmits light only to a region smaller than the light emitting surface of the light emitting section.

[0079] (Supplementary Note 4) In the authenticity determination device according to any one of Supplementary Note 1 to Supplementary Note 3, the control unit converts the code information into a character string, and compares the converted character string with a correct answer character string to determine the authenticity of the target medium.

[0080] (Supplementary Note 5) In the authenticity determination device according to Supplementary Note 4, the control unit determines the authenticity of the target medium depending on whether the number of characters that match between the character string and the correct answer character string is equal to or greater than a predetermined threshold.

[0081] (Appendix 6) In the authenticity determination device of any one of Appendices 1 to 5, the control unit acquires a second image of the target medium without irradiating the target medium with transmitted light restricted by the transmission limiting unit, identifies a hologram image represented by a hologram based on the acquired second image, and determines the authenticity of the target medium based on the identified hologram image.

[0082] (Supplementary Note 7) In the authenticity determination device of Supplementary Note 6, the control unit calculates a similarity between the identified hologram image and a correct image, and determines the authenticity of the target medium based on the calculated similarity and a similarity threshold.

[0083] (Supplementary Note 8) In the authenticity determination device of Supplementary Note 6 or Supplementary Note 7, the control unit determines the target medium to be authentic when both the authenticity determination based on the code information and the authenticity determination based on the hologram image are determined to be authentic.

[0084] (Appendix 9) The computer program causes a computer to execute a process of acquiring a first image of a target medium by irradiating the target medium with light whose transmission is limited by a transmission limiting unit that limits the transmission of light emitted from a light emitting unit, identifying code information represented by a hologram based on the acquired first image, and determining the authenticity of the target medium based on the identified code information.

[0085] (Appendix 10) The authenticity determination method includes irradiating a target medium with light whose transmission is limited by a transmission limiting section that limits the transmission of light emitted from a light emitting section, acquiring a first image of the target medium, identifying code information represented by a hologram based on the acquired first image, and determining the authenticity of the target medium based on the identified code information.

[0086] The matters described in each embodiment can be combined with each other. In addition, the independent claims and dependent claims described in the claims can be combined with each other in any and all combinations regardless of the citation format. Furthermore, the claims use a format in which a claim cites two or more other claims (multiple claim format), but this is not limited to this. A multiple claim (multi-multi claim) that cites at least one multiple claim may also be used. [Explanation of symbols]

[0087] 1 Holographic Layer 2 Deposited layer 3 Transparent base material 10 Hologram structure 11 Hologram formation area 12 Uneven surface 30 Cover 40 Recording medium reader 50, 150 Authenticity determination device 51, 101, 151 Control unit 52, 102 Light emitting part 53, 103 Transmission limiting section 54, 104 Imaging unit 55 105 Display section 56, 106 Operation section 57, 107, 152 Communications Department 58, 108, 153 Memory 59, 109, 154 Memory section 60, 110, 160 Computer Programs 61, 161 Correct Answer Information 100 Terminal Equipment

Claims

1. A light emitting portion; a transmission limiting section that limits transmission of light emitted from the light emitting section; Control unit and Equipped with The control unit is The transmitted light limited by the transmission limiting unit is irradiated onto a target medium to capture a first image of the target medium; Identifying code information represented by a hologram based on the acquired first image; determining the authenticity of the target medium based on the identified code information; Authenticity determination device.

2. The control unit is Identifying a bright spot region based on the acquired first image; Identifying code information represented by a hologram in a peripheral area of ​​the identified bright spot area; The authenticity determining device according to claim 1 .

3. The permeation limiting portion is The light is transmitted through a region that is smaller than the light-emitting surface of the light-emitting portion. The authenticity determining device according to claim 1 .

4. The control unit is Converting the code information into a character string; comparing the converted character string with a correct character string to determine the authenticity of the target medium; The authenticity determining device according to claim 1 .

5. The control unit is determining the authenticity of the target medium based on whether the number of characters that match between the character string and the correct character string is equal to or greater than a predetermined threshold; The authenticity determining device according to claim 4.

6. The control unit is acquiring a second image of the target medium without irradiating the target medium with the transmitted light restricted by the transmission restriction unit; Identifying a hologram image represented by a hologram based on the acquired second image; determining the authenticity of the target medium based on the identified hologram image; The authenticity determining device according to any one of claims 1 to 5.

7. The control unit is Calculate the similarity between the identified hologram image and a correct image; determining the authenticity of the target medium based on the calculated similarity and a similarity threshold; The authenticity determining device according to claim 6.

8. The control unit is determining the target medium as genuine when both the authenticity determination based on the code information and the authenticity determination based on the hologram image are determined to be genuine; The authenticity determining device according to claim 6.

9. a transmission limiting unit that limits the transmission of light emitted from the light emitting unit is used to irradiate the target medium with light whose transmission is limited, thereby acquiring a first image of the target medium; Identifying code information represented by a hologram based on the acquired first image; determining the authenticity of the target medium based on the identified code information; A computer program that causes a computer to carry out processing.

10. a transmission limiting unit that limits the transmission of light emitted from the light emitting unit is used to irradiate the target medium with light whose transmission is limited, thereby acquiring a first image of the target medium; Identifying code information represented by a hologram based on the acquired first image; determining the authenticity of the target medium based on the identified code information; Authenticity determination method.

Images