JP6723561B2 - Disk discriminating apparatus and disc discriminating method - Google Patents

Description

The present invention relates to a disc discriminating apparatus and a disc discriminating method, and more particularly, to a disc discriminating apparatus and a disc discriminating method for photographing a pattern on a disc surface to discriminate the authenticity of a disc to be discriminated. Note that the disk in this specification is a concept including medals and tokens used in gaming machines and coins that are currency.

A technique for imaging the front surface or the back surface of a medal or coin (in the present specification, generically referred to as “front surface”) and determining authenticity based on the pattern of the front surface using a captured image has been conventionally proposed, For example, there are those disclosed in Patent Documents 1 and 2.

Generally, a disc such as a medal or a coin has a pattern formed on its surface, and when the image is captured by the imaging device, the pixel array of the imaging device interferes with the pattern to cause moire. May occur. When capturing an image of a disc, the generation state of moire changes depending on the rotation angle of the disc. In other words, the pattern in the acquired image changes depending on the rotation angle of the disc under the influence of moire. Therefore, when deriving the degree of difference or the degree of coincidence by comparing the captured image of the disc to be discriminated with an image serving as a reference for comparison (hereinafter referred to as a reference image), the degree of difference or the degree of coincidence changes due to the influence of moire, There is a problem that a desired discrimination result cannot be obtained.

In the first conventional technique disclosed in Patent Document 1, considering that a moire appears and the reflectance changes remarkably depending on the angle between the pixel array of the image sensor and the pattern, the reference is excluded except for a specific portion depending on the rotation angle. Matching with the image.

On the other hand, in the second conventional technology disclosed in Patent Document 2, recognition accuracy is improved by masking a portion such as a year part where characters are changed depending on the year of coin issuance and the pattern itself is partially changed. We are reducing the causes of decline.

JP 2004-157975 A (claim 1, claim 8, paragraph numbers 0018, 0019, FIG. 15) JP-A-9-27056 (paragraph numbers 0013 and 0019, FIG. 3)

In the first conventional technology, there is no specific disclosure about a method of setting a specific area to be excluded. Similarly, in the second conventional technique, there is no specific disclosure about a method of setting a masked portion. Generally, there are various patterns of discs such as medals and coins, and it is necessary to set an area where moire occurs (hereinafter referred to as a moire area) depending on the type of the disc. Although it is possible to manually set the moire area while visually confirming the moire generation state, in that case, there is a problem that a great deal of time and labor is required. Further, when the visual setting is performed, the setting accuracy may vary. If the setting accuracy of the moire area varies, the accuracy of discriminating the authenticity of discs such as medals and coins is significantly reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to be able to automatically set a moire area of a disc and to reduce the disc identification accuracy due to the moire. It is to provide a disc discriminating apparatus and a disc discriminating method capable of preventing the disc discriminating device. Other objects of the present invention not specified herein will be apparent from the following description and the accompanying drawings.

In order to achieve this object, the disc discriminating apparatus and disc discriminating method according to the present invention are configured as follows.

(1) The disc discriminating apparatus of the present invention discriminates whether the disc to be discriminated is true or false by comparing the discriminated image corresponding to the disc to be discriminated and the reference image with the moire area excluded from the effective pixels. A reference image generation unit that is an apparatus and that generates a reference image by integrating a plurality of input images corresponding to each of a plurality of discs to be discriminated as genuine discs, each of the plurality of input images, and the reference image. A moire image selection unit that selects a plurality of moire images having the moire area from the plurality of input images based on a comparison result with, and an integrated moire image obtained by integrating the plurality of moire images and the reference image. A mask image generation unit that generates a mask image that excludes the moire area from effective pixels based on a comparison result, and the discrimination by applying the mask image to compare the inputted discrimination target image and the reference image. The disc discriminating apparatus includes a discriminating unit for discriminating the authenticity of the target disc.

The disc discriminating apparatus of the present invention includes a reference image generation unit that generates a reference image, a moiré image selection unit that selects a moiré image from an input image, and a mask image that generates a mask image that excludes a moiré region from effective pixels. It has a generation unit and a discrimination unit that discriminates the authenticity of the disc to be discriminated. The reference image generation unit integrates a plurality of input images corresponding to a plurality of discs to be discriminated as genuine discs to generate a reference image. The moiré image selection unit selects, from the plurality of input images, a plurality of moiré images having a moiré area based on a comparison result between each of the plurality of input images and the reference image. The mask image generation unit generates a mask image that excludes a moire area from effective pixels based on a comparison result between an integrated moire image obtained by integrating a plurality of moire images and a reference image. The discriminating section discriminates the authenticity of the disc to be discriminated by applying a mask image to the discriminated image corresponding to the disc to be discriminated and the reference image and comparing them. In the first disc discriminating apparatus, a mask image is generated based on a comparison result of an integrated moire image obtained by integrating a plurality of moire images selected from a plurality of input images and a reference image. Therefore, it is possible to automatically set the moire area and the like of the disc. Further, by applying a mask image to each of the to-be-determined image and the reference image corresponding to the disc to be discriminated and excluding the moire area from the effective pixels, it is possible to prevent the disc discrimination accuracy from being lowered due to the moire. It will be possible.

(2) In a preferred example of the disc discriminating apparatus of the present invention, an evaluation value derivation unit that derives an evaluation value of matching with respect to the reference image for each of the plurality of input images, and a plurality of evaluation value derivation units that derive the evaluation value. Further comprising a determination threshold setting unit that sets a determination threshold of the moire image from the frequency distribution of the evaluation value, the moire image selection unit, based on the determination threshold for each of the evaluation value of the plurality of input images. The moire image is selected by the determination. In this case, there is an advantage that it is possible to automatically select a plurality of moire images having a moire area from a plurality of input images.

(3) In another preferable example of the disc discriminating apparatus of the present invention, the judgment threshold setting unit sets the judgment threshold based on the frequency distribution on the side where the evaluation value is higher than the average value of the frequency distribution. .. In this case, there is an advantage that the determination threshold value can be set according to the moiré occurrence state.

(4) In still another preferred example of the disc discriminating apparatus of the present invention, the mask image generation unit sets a threshold value at which the degree of separation in the frequency distribution of the difference pixel values between the integrated moiré image and the reference image is maximum. As the mask image, an image obtained by binarizing the difference image between the integrated moire image and the reference image is used.

(5) The disc discrimination method of the present invention discriminates the disc to be discriminated by discriminating the authenticity of the disc to be discriminated by comparing the discriminated image corresponding to the disc to be discriminated and the reference image by excluding the moire area from effective pixels. a disk discriminating method of the device, the higher the reference image generation factory for generating the reference image by integrating a plurality of input images corresponding to each of a plurality of disks to be discriminated as genuine disc, the plurality of input images and a plurality of moire images having the moire on the basis of a comparison result between each said reference image as moiré image selection Engineering for selecting from among the plurality of input images, the integrated moire image obtained by integrating the plurality of moire images and as the mask image generation factory for generating the mask image to exclude the moire from effective pixels based on the comparison result between the reference image and an input device under determination image and the reference image applying the mask image and , a more discriminating Engineering to determine the authenticity of the determination target disk by comparing Te is a disk discriminating method for a disk discriminating device comprising a.

The disk discriminating method for a disk discriminating device of the present invention, the higher the reference image generation factory for generating the reference image, the higher the moire image selection Engineering for selecting moiré image from the input image, excluding moire from the effective pixel mask and as the mask image generation factory for generating an image, and a degree determination Engineering to determine the authenticity of the determination target disk. The higher the reference image generation engineering, to generate a reference image by integrating a plurality of input images corresponding to each of a plurality of disks to be discriminated as genuine disc. The higher the moire image selection Engineering, selects a plurality of moiré images with moire on the basis of the comparison result between the respective reference image of the plurality of input images from a plurality of input images. The higher the mask image generation engineering, to produce an excluded mask image Moire area from the effective pixels based on the comparison result of the accumulated moire image and the reference image obtained by integrating a plurality of moire images. The more discriminating engineering to determine the authenticity of the discrimination target disk by comparing the target discrimination image and the reference image corresponding to the determination target disk by applying a mask image. In the first disc discriminating method, a mask image is generated based on a comparison result between an integrated moire image obtained by integrating a plurality of moire images selected from a plurality of input images and a reference image. Therefore, it is possible to automatically set the moire area and the like of the disc. Further, by applying a mask image to each of the to-be-determined image and the reference image corresponding to the disc to be discriminated and excluding the moire area from the effective pixels, it is possible to prevent the disc discrimination accuracy from being lowered due to the moire. It will be possible.

In a preferred embodiment of a disk discriminating method in a disk discriminating device (6) The present invention, a higher evaluation value deriving engineering to derive the evaluation value of the matching with respect to the reference image for each of the plurality of input images, as the evaluation value deriving Engineering from the frequency distribution of the plurality of the evaluation value as the determination threshold setting factory that sets the determination threshold for the moire image derived in further comprising a, in extent the moire image selection Engineering, the evaluation values of the plurality of input images The moire image is selected by making a judgment based on the judgment threshold for each of them. In this case, there is an advantage that it is possible to automatically select a plurality of moire images having a moire area from a plurality of input images.

(7) In another preferred embodiment of the disk discriminating method for a disk discriminating device of the present invention, the in the determination threshold setting Engineering degree, on the basis of the said frequency distribution of said evaluation value than the average value of the frequency distribution is high side Set the judgment threshold. In this case, there is an advantage that the determination threshold value can be set according to the moiré occurrence state.

(8) In yet another preferred embodiment of a disk discriminating method in a disk discriminating device of the present invention, in the mask image generation Engineering degree, the maximum degree of separation in the frequency distribution of the differential pixel values between the reference image and the accumulated moire images The image obtained by binarizing the difference image between the integrated moire image and the reference image is used as the mask image with a value of

With the disc discriminating apparatus and disc discriminating method of the present invention, (a) it is possible to automatically set the moire area of the disc, and (b) it is possible to prevent deterioration of disc discriminating accuracy due to moire. The effect that it becomes possible is obtained.

It is a schematic block diagram which shows the disc discriminating apparatus of one Example of this invention. FIG. 2 is a cross-sectional view of a main part showing an image acquisition section which constitutes the disc discriminating apparatus of FIG. 1. FIG. 2 is a schematic block diagram showing an image processing unit and an image storage unit that form the disc discriminating apparatus of FIG. 1. 6 is a flowchart for explaining the operation of the disc discriminating apparatus of FIG. 1. 5 is a flowchart showing details of the reference image generation process of FIG. 4. 6 is a flowchart showing details of the captured image acquisition process of FIG. 5. 6 is a flowchart showing details of the preprocessing of FIG. 5. 6 is a flowchart showing details of the image rotation process of FIG. 5. 6 is a flowchart showing details of the comparison determination process of FIG. 5. 5 is a flowchart showing details of the moire image determination processing of FIG. 4. 10 is a flowchart showing the details of the moire image determination processing in FIG. 4, which is a continuation of FIG. 10. 5 is a flowchart showing details of the mask image generation processing of FIG. 4. 5 is a flowchart showing details of the authenticity determination process of FIG. 4. 14 is a flowchart showing details of the comparison determination process of FIG. 13. 13 is a flowchart showing details of a modified example of the mask image generation processing of FIG. 12. 14 is a flowchart showing details of a modified example of the authenticity determination process of FIG. 13.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(Constitution)
1 to 3 show a disc discriminating apparatus 1 according to an embodiment of the present invention. The disc discriminating apparatus 1 has a function of acquiring a captured image of the front surface or the back surface (hereinafter, generically referred to as “front surface”) of the disc D and discriminating the authenticity of the disc D based on the captured image. As shown in FIG. 1, the disc discriminating apparatus 1 includes an image acquisition unit 2, an imaging timing sensor 3, a control unit 4, an image processing unit 5, an image storage unit 6, an input/output interface (I/F) 7, and a status indicator. 8 and a discrimination reference storage unit 9.

First, the image acquisition unit 2 will be described with reference to FIGS. 1 and 2. As shown in FIG. 2, the image acquisition unit 2 has a function of acquiring a captured image of the surface of the disc D conveyed through the disc conveyance path 31 and outputting the captured image data ID of the disc D to the control unit 4. The image acquisition unit 2 includes a light projecting device 11, a two-dimensional imaging device 12, and a half mirror 26. The image acquisition unit 2 is arranged corresponding to the imaging window 33 opened in the base plate 32 that supports one surface of the disc D in the disc transport path 31.

The imaging window 33 defines an imaging area 35 of the disc D that is transported along the disc transport path 31. The imaging window 33 has a pair of long sides that are substantially parallel to the transport direction DL of the disc D that is transported in the disc transport path 31, and a pair of short sides that are substantially perpendicular to the transport direction DL. A translucent plate 34 having translucency is arranged in the imaging window 33, and the surface of the translucent plate 34 on the side of the disc transport path 31 is substantially the surface of the base plate 32, in other words, the bottom surface of the disc transport path 31. It is composed of one. The length of the pair of long sides of the imaging window 33 is set larger than the diameter of the disc D. This is for obtaining information about the diameter of the disc D in the longitudinal direction of the imaging window 33. The short sides of the imaging window 33 are arranged so that the straight lines connecting the midpoints of the short sides of the imaging window 33 to each other and the locus of the center of the disc D transported through the disc transport path 31 are substantially coincident with each other. This is for surely obtaining information about the surface of the disc D.

The light projecting device 11 has a function of projecting light onto the surface of the disk D moving on the disk transport path 31. The light projecting device 11 is, for example, a surface light projecting device 21. This is because by using the surface light projecting device 21, it is possible to perform imaging without the influence of shadow even if the rotation phase of the disk D is different. The surface light projecting device 21 includes a light emitting element 22, a light guide plate 23, a reflection sheet 24, and a diffusion sheet 25. In this embodiment, the light emitting element 22 is an LED (Light Emitting Diode, light emitting diode). The light emitting element (that is, the LED) 22 is a light source for projecting light onto the disk D. A white LED is used for the light emitting element 22, and the light emitting element 22 projects white visible light. However, a three-color LED can also be used as the light emitting element 22. As shown in FIG. 2, since the light emitting element 22 is arranged so as to face the side end surface of the light guide plate 23, the light emitting element 22 can be arranged in a plane parallel to the disc transport path 31, and the installation space is small. The position of the light emitting element 22 shown in FIG. 2 is shown for convenience.

In the present embodiment, the light guide plate 23 is a rectangular thin plate made of resin from the viewpoint of low cost, and its surface is arranged parallel to the disc transport path 31. The resin exhibits a milky white color when it is transparent or contains a diffusing material. When the diffusing material is mixed, the diffusing sheet 25 becomes unnecessary. The light guide plate 23 can also be composed of a glass substrate. In this embodiment, the light guide plate 23 faces the image pickup area 35. The reflection sheet 24 has a function of preventing light from diffusing from the light guide plate 23 to the opposite side of the disc transport path 31 and reflecting the light to the disc transport path 31 side. The reflection sheet 24 is in close contact with the surface of the light guide plate 23 located on the opposite side of the disc transport path 31. Instead of the reflection sheet 24, a silver film may be deposited on the light guide plate 23. The diffusion sheet 25 has a function of uniformly diffusing the light projected from the surface of the light guide plate 23 on the side of the disc transport path 31. Therefore, the projection light from the light emitting element 22 guided by the light guide plate 23 or reflected by the reflection sheet 24 is made into a uniform light amount over the entire surface by the diffusion sheet 25, and is projected toward the disc transport path 31. Be illuminated. As a result, the light is uniformly projected onto the disk D. The projection light projected from the diffusion sheet 25 is projected at a right angle to the disk transport path 31, in other words, the disk D moving in the disk transport path 31. This is because no optical shadow is created by the unevenness of the flat surface of the disk D. Since the light guide plate 23, the reflection sheet 24, and the diffusion sheet 25 are thin, the light projecting device 11 can be downsized.

The surface light projecting device 21 of the present embodiment is configured to include the LED as the light emitting element 22, the light guide plate 23, the reflection sheet 24, and the diffusion sheet 25, but is not limited to this. For example, an LED array in which a plurality of LEDs are arranged two-dimensionally, parallel light in which a point light source such as an LED and a lens are combined can be used. Further, in the present embodiment, an LED is used as the light emitting element 22, but the light emitting element 22 is not limited to this, and a light source such as a cold cathode ray tube or a halogen lamp may be used.

The half mirror 26 has a function of reflecting a part of the incident light and transmitting a part of the incident light. Specifically, it has a function of transmitting light emitted from the light projecting device 11 and reflecting light reflected from the disk D. In other words, the half mirror 26 projects the light projected from the light projecting device 11 at right angles to the disk D in the disk transport path 31, and reflects the light reflected from the disk D in a direction parallel to the disk transport path 31. To reflect. The half mirror 26 is tilted at an angle of 45 degrees with respect to the surface of the disc transport path 31 on the side of the imaging region 35. In the present embodiment, the half mirror 26 is formed by vapor-depositing or plating chromium as a reflection film on an organic glass formed of a thin light-transmitting resin. However, without being limited to this, optical glass such as borosilicate glass, quartz glass, zirconia, ruby, and sapphire may be used as the substrate glass instead of the organic glass. Instead of chromium, a metal film such as tin and silver or a dielectric material such as titanium oxide, silicon oxide, niobium pentoxide, tantalum pentoxide and magnesium fluoride may be used as the reflective film. Further, as the half mirror 26, a prism type half mirror in which two right-angle prisms are bonded together may be used instead of thin organic glass.

The two-dimensional image pickup device 12 includes a condenser lens 41 and an image pickup element 42. The condenser lens 41 has a function of condensing the light reflected by the half mirror 26 into a predetermined small range. Due to the above function, the condenser lens 41 is a convex lens having a predetermined refractive index, and is arranged on the side of the half mirror 26, in other words, in the direction in which the half mirror 26 is inclined, and is equal to or smaller than the half mirror 26. Have a diameter. It is preferable to devise the shape of the light projecting device 11 and the like to reduce the size of the condenser lens 41. This is because the two-dimensional imaging device 12 is low-priced and downsized. The image sensor 42 has a function of capturing an image collected by the condenser lens 41. The image pickup element 42 is arranged on the side opposite to the half mirror 26 with respect to the condenser lens 41 and at a position where the surface image of the disk D is formed via the condenser lens 41. A CCD image sensor or a CMOS image sensor is adopted as the image pickup element 42 for downsizing.

Next, the image pickup timing sensor 3 will be described. The imaging timing sensor 3 has a function of detecting the timing at which the disc D transported on the disc transport path 31 passes over the imaging area 35. The image pickup timing sensor 3 is arranged so that the image pickup timing sensor 3 can detect the disc D or a transport unit (not shown) that transports the disc D when almost the entire surface of the disc D reaches above the half mirror 26. .. Therefore, the imaging timing sensor 3 outputs the timing signal TS indicating the timing at which the disk D can be optimally imaged as a detection signal of the disk D.

The control unit 4 controls the operation of the image pickup device 42 and the light emitting device 22 based on the timing signal TS output from the image pickup timing sensor 3, and stores the picked-up image acquired by the image pickup device 42 in the image storage unit 6. It has a function of causing the image processing unit 5 to execute predetermined image processing based on the stored captured image. As shown in FIG. 3, the control unit 4 outputs the captured image data ID of the disc D output from the image acquisition unit 2 to the captured image holding unit 600 of the image storage unit 6 described later. Further, the control unit 4 outputs the image processing control signal PCS to the image processing unit 5 to the image processing unit 5. Further, the control unit 4 outputs a storage unit control signal MCS for the image storage unit 6 to the image storage unit 6. The control unit 4 is composed of, for example, a microcomputer that operates based on a predetermined program.

As shown in FIG. 3, the image processing unit 5 includes a preprocessing unit 500, a reference image generation unit 510, a moire image processing unit 520, a mask image processing unit 540, and a determination unit 560, and is stored in the image storage unit 6. It has a function of performing various processes on the captured image. The image processing unit 5 is controlled by the image processing control signal PCS output from the control unit 4. Details of the image processing unit 5 will be described later.

Next, the image storage unit 6 will be described. As illustrated in FIG. 3, the image storage unit 6 includes a captured image holding unit 600, a processed image holding unit 602, an input image holding unit 604, a reference image holding unit 606, a moire image holding unit 608, and a mask image holding unit 610. .. The picked-up image storage unit 600 holds the picked-up image of the disc D to be discriminated based on the picked-up image data ID outputted from the control unit 4, and also the picked-up image data ID of each disc to be discriminated to be held. Is output to the preprocessing unit 500 of the image processing unit 5. The processed image holding unit 602 temporarily holds the captured image processed by the preprocessing unit 500 of the image processing unit 5 (hereinafter referred to as the preprocessed image), and also holds the held preprocessed image in the preprocessed image data PD. Has a function of outputting to the reference image generation unit 510 and the determination unit 560 of the image processing unit 5. The input image holding unit 604 temporarily holds the image processed by the reference image generation unit 510 (hereinafter referred to as the input image), and uses the held input image as the input image data BD as the reference image of the image processing unit 5. It has a function of outputting to the generation unit 510 and the moire image processing unit 520.

The reference image holding unit 606 holds the reference image generated by the reference image generation unit 510 of the image processing unit 5, and uses the held reference image as the reference image data RD, the moire image processing unit 520 of the image processing unit 5, It has a function of outputting to the mask image processing unit 540 and the discrimination unit 560. The moire image holding unit 608 temporarily holds the input image selected by the moire image processing unit 520 of the image processing unit 5 as having a moire area as a moire image, and the held moire image as the moire image data MD. It has a function of outputting to the moire image processing unit 520. Further, the moire image holding unit 608 temporarily holds the accumulated moire image obtained by accumulating a plurality of moire images in the moire image processing unit 520 of the image processing unit 5 and also accumulates the accumulated moire images. It has a function of outputting the image data IMD to the mask image processing unit 540 of the image processing unit 5. The mask image holding unit 610 holds the mask image generated by the mask image processing unit 540 of the image processing unit 5, and outputs the held mask image as the mask image data BMD to the determination unit 560 of the image processing unit 5. Have a function. The captured image holding unit 600, the processed image holding unit 602, the input image holding unit 604, and the moire image holding unit 608 are configured by, for example, a RAM (Random Access Memory) from the viewpoint of data read/write speed. The reference image holding unit 606 and the mask image holding unit 610 are configured by, for example, a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) from the viewpoint of sustainability of data holding. The operation of the captured image holding unit 600, the processed image holding unit 602, the input image holding unit 604, the reference image holding unit 606, the moire image holding unit 608, and the mask image holding unit 610 is performed by the storage unit control signal output from the control unit 4. Controlled by MCS.

The input/output interface (I/F) 7 has a function of electrically connecting to a main body device (not shown) in which the disk discriminating apparatus 1 is incorporated. By connecting the main body device to the disk discriminating apparatus 1 via the input/output interface (I/F) 7, desired signals can be input/output to/from the main body device.

The status indicator 8 has a function of displaying the operating status of the disc discriminating apparatus 1. The status indicator 8 is composed of, for example, a plurality of LEDs (not shown) having different light emission colors, and the light emission of these LEDs is controlled by the control unit 4, so that various statuses of the disk discriminating apparatus 1 (for example, Normal operation, error occurrence, etc.) is notified. A display device such as a liquid crystal panel can also be used as the status indicator 8.

The discrimination criterion storage unit 9 has a function of storing a threshold value for discriminating a false disc in the disc discriminating apparatus 1. The discrimination reference storage unit 9 outputs the discrimination reference data SLS to the control unit 4. The control unit 4 determines the authenticity of the disc D to be discriminated based on the threshold value based on the discrimination reference data SLS sent.

Next, the image processing unit 5 will be described in detail with reference to FIG. The image processing unit 5 has a function of generating a reference image for discriminating the disc D to be discriminated based on the surface pattern thereof, a function of discriminating the presence or absence of a moire area in the input image of the disc D, and a disc of the disc D to be discriminated. It has a function of generating a mask image for masking the moire area of the preprocessed image and the reference image, and a function of discriminating the pattern on the surface of the disc D to be discriminated based on the reference image. The image processing unit 5 includes a preprocessing unit 500, a reference image generation unit 510, a moire image processing unit 520, a mask image processing unit 540, and a determination unit 560.

First, the preprocessing unit 500 will be described. The pre-processing unit 500 performs a reference image generation process in the reference image generation unit 510, a moiré image selection process in the moiré image processing unit 520, and a captured image of the disk D held in the captured image holding unit 600 of the image storage unit 6, and The determination unit 560 has a function of performing a predetermined process for efficiently executing each of the determination processes. The picked-up image of the disc D held in the picked-up image holding unit 600 is input to the preprocessing unit 500 as a picked-up image data ID and processed by the preprocessing unit 500. Then, the preprocessed captured image of the disc D (preprocessed image) is output to the processed image holding unit 602 of the image storage unit 6 and held by the processed image holding unit 602 of the image storage unit 6. As shown in FIG. 3, the preprocessing unit 500 includes an edge extraction unit 502, a center extraction unit 504, and an image cutout unit 506.

The edge extraction unit 502 has a function of extracting edges in the captured image held in the captured image holding unit 600. The edge extraction is a process of extracting, as an edge (feature), a portion where the brightness or color of a pixel in the image is largely changed. Edge extraction can be performed by using a filter (Sobel filter and Prewitt filter) based on the first derivative and a filter (Laplacian filter) based on the second derivative.

The center extracting unit 504 has a function of extracting the center position of the disc D in the captured image based on the captured image held in the captured image holding unit 600. In other words, the coordinate value indicating the center of the disk D in the captured image is calculated. A known method is used to extract the center position. For example, one edge and the other edge of the disk D are detected for each line extending in the vertical axis (Y-axis) direction in the captured image, and the detected both edges are detected. The center point of the disk D is defined as the midpoint between the two peripheral edge portions on the line where the distance between the portions is maximum. However, other methods can be used to extract the center position.

The image cutout unit 506 has a function of cutting out the image, the center position of which is extracted by the center extraction unit 504, into a size set in advance based on the center position. In the present embodiment, the image cutout unit 506 cuts out the image, the center position of which is extracted by the center extraction unit 504, into a square shape so that the center position of the disc D and the intersection of the diagonal lines match. The image may be cut out in a rectangular shape or in a circular shape according to the outer peripheral edge of the disc D.

Next, the reference image generation unit 510 will be described. The reference image generation unit 510 has a function of performing a predetermined process for generating a reference image serving as a reference for discriminating the authenticity of the disc D. The reference image generation unit 510 processes the preprocessed image based on the processed image data PD sent from the processed image holding unit 602 of the image storage unit 6 and the input image data BD sent from the input image holding unit 604 of the image storage unit 6. Predetermined processing is performed on each of the input image based on the reference image and the reference image based on the reference image data RD sent from the reference image holding unit 606 of the image storage unit 6. Then, the preprocessed image processed by the reference image generation unit 510 is output to the input image holding unit 604 of the image storage unit 6 as the input image data BD, and held as the input image by the input image holding unit 604. The pre-processed image processed by the reference image generation unit 510 is output as reference image data RD to the reference image holding unit 606, and is held as a reference image by the reference image holding unit 606. Further, the reference image processed by the reference image generation unit 510 is output to the reference image holding unit 606 as reference image data RD and held as the reference image by the reference image holding unit 606. As shown in FIG. 3, the reference image generation unit 510 includes a comparison determination unit 512, an image rotation unit 514, and an image integration unit 516.

The comparison determination unit 512 compares the pixel values for each pixel (pixels having the same coordinate value) of the desired two images, and determines the degree of difference (hereinafter referred to as the degree of difference) of the two images or the degree of matching (hereinafter referred to as the match). It has a function of determining whether or not the two images match each other based on the degree. For example, in the case of making a determination based on the degree of difference, if the total number of pixels whose pixel values do not match exceeds a predetermined threshold value stored in the determination reference storage unit 9, it is determined that the two images do not match. On the other hand, in the case of determining by the degree of coincidence, when the total value of the number of pixels having the same pixel value exceeds the predetermined threshold value held in the discrimination reference storage unit 9, it is determined that the two images match. In this embodiment, the judgment is made based on the degree of difference. Further, the comparison determination unit 512 has a function of correcting a rotation angle shift between two images and a shift in the horizontal direction (direction parallel to the images) (hereinafter, collectively referred to as relative position shift). The correction of the relative positional deviation can be performed by, for example, the method of correcting the rotational deviation and the positional deviation disclosed in Japanese Patent Laid-Open No. 2016-134073. The comparison determination unit 512 determines the relative positional deviation between the reference image stored in the reference image storage unit 606 of the image storage unit 6 and the preprocessed image of the disc number i stored in the processed image storage unit 602 of the image storage unit 6. Make a correction. The comparison determination unit 512 compares the reference image with the preprocessed image of the disk number i for which the relative displacement correction has been performed, and calculates the degree of difference DF. The comparison determination unit 512 determines whether or not the preprocessed image of the disc number i matches the reference image based on the calculated difference DF.

The image rotation unit 514 has a function of rotating a desired image around the center position of the disc D. The image rotation unit 514 rotates the reference image held in the reference image holding unit 606 of the image storage unit 6 about the center position of the disk D at each predetermined rotation angle difference θd. In other words, the image rotation unit 514 has a reference image corresponding to the rotation angle θ (hereinafter referred to as a reference image of the rotation angle θ) and a reference corresponding to the rotation angle “θ+θd” obtained by rotating the rotation angle difference θd. Generate an image. In this way, by preparing a plurality of reference images rotated for each rotation angle difference θd, the comparison determination process of step S21 of the reference image generation process of FIG. 5 described later and the true determination of FIG. 13 described later. In the comparison determination process of step S145 of the false determination process, it is not necessary to compare the preprocessed image with the reference image while rotating the preprocessed image, and the comparison determination process between the preprocessed image and the reference image can be efficiently executed.

The image integration unit 516 has a function of performing image integration processing on two desired images. The image integration process is a process of removing noise by sharpening and smoothing edges of an image. The image integration process can be performed by a simple integration in which the pixel values of each pixel are simply accumulated while the plurality of image weights to be integrated are constant. The image integration unit 516 compares the reference image of the rotation angle “0 degrees” held in the reference image holding unit 606 of the image storage unit 6 and the input image held in the input image holding unit 604 of the image storage unit 6. Perform image integration processing. The image subjected to the image integration processing is output to the reference image holding unit 606 as the reference image data RD and held in the reference image holding unit 606 as the reference image of the rotation angle “0 degree”.

Next, the moire image processing unit 520 will be described. The moire image processing unit 520 has a function of determining whether or not there is a moire region in a desired image and selecting an image having a moire region as a moire image. Furthermore, the moire image processing unit 520 performs image integration processing on the selected plurality of moire images. The moire image processing unit 520 determines whether or not each of the input images of the disk number i held in the input image holding unit 604 of the image storage unit 6 has a moire area. The moire image processing unit 520 outputs the input image determined to have the moire area to the moire image holding unit 608 of the image storage unit 6 as the moire image data MD. The image determined to have the moire area is stored and held as the moire image with the moire number j by the moire image holding unit 608. Further, the moiré image processing unit 520 performs image integration processing on all moiré images held in the moiré image holding unit 608. The moire image processing unit 520 outputs the image subjected to the image integration processing to the moire image holding unit 608 as the integrated moire image data IMD. The image subjected to the image integration processing is held by the moire image holding unit 608 as an integrated moire image. As shown in FIG. 3, the moire image processing unit 520 includes an evaluation value derivation unit 522, a determination threshold value setting unit 524, a moire image selection unit 526, and a moire image integration unit 528.

The evaluation value derivation unit 522 has a function of comparing pixel values of respective desired pixels (pixels having the same coordinate value) of the two images and deriving an evaluation value from the degree of difference or the degree of coincidence of the two images. The evaluation value derivation unit 522 compares the pixel value of each pixel of the reference image held in the reference image holding unit 606 of the image storage unit 6 and each pixel of the input image of each disc number i held in the input image holding unit 604. The degree of difference or the degree of coincidence is calculated, and the evaluation value EV of the input image of each disc number i is derived based on the calculated degree of difference or the degree of coincidence. The method of calculating the degree of difference or the degree of coincidence in the evaluation value derivation unit 522 is the same as the method of calculating the degree of difference or the degree of coincidence in the comparison determination unit 512. The derived evaluation value EV is stored in a storage area (not shown) of the image storage unit 6.

The determination threshold setting unit 524 has a function of setting a determination threshold for determining whether or not the input image of each disc number i has a moire area. The determination threshold setting unit 524 sets the determination threshold based on the frequency distribution table of the evaluation value EV derived by the evaluation value deriving unit 522. The set determination threshold value is stored in a storage area (not shown) of the image storage unit 6.

The moire image selection unit 526 has a function of determining whether or not a desired image has a moire area and a function of selecting an image having a moire area. Based on the evaluation value EV derived by the evaluation value derivation unit 522 and the determination threshold value set by the determination threshold value setting unit 524, the moire image selection unit 526 determines whether the input image of each disk number i has a moire area. Determine whether or not. For example, when the evaluation value EV is smaller than the determination threshold value, the moire image selection unit 526 determines that the input image of the disc number i has a moire area. The input image of the disc number i determined to have the moire area is output to the moire image holding unit 608 of the image storage unit 6 as the moire image data MD, and is held by the moire image holding unit 608 as the moire image of the moire number j. It

The moire image integration unit 528 has a function of performing image integration processing on a desired plurality of images. The moire image integration unit 528 performs image integration processing on all the moire images stored in the moire image storage unit 608 of the image storage unit 6. The image integration process of the moire image is the same as the image integration process in the image integration unit 516 of the reference image generation unit 510. The moiré image subjected to the image integration processing is output to the moiré image holding unit 608 as integrated moiré image data IMD, and is held by the moiré image holding unit 608 as an integration moiré image.

Next, the mask image processing unit 540 will be described. The mask image processing unit 540 has a function of generating a mask image for excluding the moire region from the effective pixels when comparing two desired images (pixels having the same coordinate value). The mask image processing unit 540 generates a mask image based on the reference image held in the reference image holding unit 606 of the image storage unit 6 and the integrated moire image held in the moire image holding unit 608. The image generated by the mask image processing unit 540 is output as mask image data BMD to the mask image holding unit 610 of the image storage unit 6, and held as a mask image by the mask image holding unit 610. As shown in FIG. 3, the mask image processing unit 540 has a mask threshold setting unit 542 and a mask image generation unit 544.

The mask threshold value setting unit 542 calculates pixel value difference information for each pixel (pixels having the same coordinate value) of the desired two images, and sets an effective pixel and an ineffective pixel based on the calculated difference information. It has a function of setting a mask threshold value. To calculate the difference information, for example, the background difference method can be used, and the absolute value of the difference between the pixel values of each pixel (pixels having the same coordinate value) of the two images (hereinafter referred to as the difference pixel value) is the difference. It is calculated as information. The mask threshold is set based on the frequency distribution table for the calculated difference pixel value of each pixel. A general threshold value setting method for binarized image processing such as a discriminant analysis method or a mode method can be used for setting the mask threshold value. The mask threshold setting unit 542 calculates a difference pixel value of each pixel, which is difference information between the reference image held in the reference image holding unit 606 and the integrated moire image held in the moire image holding unit 608. The mask threshold setting unit 542 sets the mask threshold based on the calculated frequency distribution table of the difference pixel value of each pixel. The set mask threshold value is stored in a storage area (not shown) of the image storage unit 6.

The mask image generation unit 544 has a function of generating a mask image. The mask image generation unit 544 applies the mask threshold set by the mask threshold setting unit 542 to the image based on the difference information between the reference image and the integrated moire image (hereinafter referred to as the difference image), and the difference image is generated. Binarize. In other words, the mask image generation unit 544 masks the difference image based on the difference pixel value of each pixel (pixel having the same coordinate value) between the reference image and the integrated moire image calculated by the mask threshold setting unit 542. The mask threshold set by the threshold setting unit 542 is applied, and the difference image is binarized. The binarized difference image is held in the mask image holding unit 610 of the image storage unit 6 as a mask image.

Next, the determination unit 560 will be described. The discriminating unit 560 sets the preprocessed image of the disc D to be discriminated held in the processed image holding unit 602 of the image storage unit 6 as the discriminated image, and holds the discriminated image and the reference image holding unit 606 of the image storage unit 6. After applying the mask image held in the mask image holding unit 610 of the image storage unit 6 to each of the plurality of reference images, the discriminating target disc is discriminated from the discriminated image by comparing the discriminating image with each reference image. It has a function of determining the authenticity of D. The determination result is output from the image processing section 5 to the control section 4 as a determination signal IS. The determination unit 560 includes a mask image application unit 562 and a difference degree derivation unit 564.

The mask image application unit 562 has a function of applying the mask image held in the mask image holding unit 610 of the image storage unit 6 to a desired image. The mask image application unit 562 applies an image storage unit to each of the determination target image stored in the processed image storage unit 602 of the image storage unit 6 and the plurality of reference images stored in the reference image storage unit 606 of the image storage unit 6. The mask image held in the mask image holding unit 610 of No. 6 is applied. As a result, the moire area of each of the discriminating image and the plurality of reference images is excluded from the effective pixels for discriminating the authenticity of the disc D.

The dissimilarity deriving unit 564 compares the pixel values for each pixel (pixels having the same coordinate value) of the desired two images, and determines whether or not the two images match based on the dissimilarity or the degree of coincidence of the two images. It has the function to judge. For example, in the case of determining by the degree of difference, when the total value of the number of pixels whose pixel values do not match exceeds a predetermined threshold stored in the image storage unit 6, it is determined that the two images do not match. On the other hand, in the case of determining the degree of coincidence, if the total value of the number of pixels having the same pixel value exceeds a predetermined threshold value stored in the image storage unit 6, it is determined that the two images match. In this embodiment, the judgment is made based on the degree of difference.

The edge extraction unit 502, the center extraction unit 504, the comparison determination unit 512, the image rotation unit 514, the image integration unit 516, the evaluation value derivation unit 522, the determination threshold value setting unit 524, and the moire image selection unit that configure the image processing unit 5. 526, moire image accumulating unit 528, mask threshold setting unit 542, mask image generating unit 544, mask image applying unit 562, and dissimilarity deriving unit 564 may be hardware or software as long as they have respective functions. You may comprise. It is possible to use part of the hardware and the rest of the software.

(motion)
Next, the operation of the disc discriminating apparatus 1 will be described with reference to FIGS. The captured image obtained by the operation of the disc discriminating apparatus 1 is an image of either the front surface or the back surface of the disc D. Therefore, when the patterns on the front surface and the back surface of the disc D are different, it is necessary to generate the reference images for the front surface and the back surface, and it is necessary to compare them with the reference images for the front surface and the back surface. In this embodiment, the patterns on the front surface and the back surface of the disk D are the same.

First, as shown in FIG. 4, initialization is performed in step S1. In the initialization, the frame rate of the image pickup element 42, the sensitivity of the image pickup timing sensor 3, and the like are set.

In the next step S2, it is determined whether the registration mode for registering the reference image or the discrimination mode for discriminating the authenticity of the disc D is selected. When it is determined in step S2 that the registration mode is selected, the process proceeds to step S3. On the other hand, if it is determined in step S2 that the determination mode has been selected, the process proceeds to step S8.

In step S3, it is determined whether or not a reference image is generated. When it is determined that the generation of the reference image is selected, the process proceeds to step S4, the reference image generation process of generating the reference image is executed, and the process proceeds to step S5. On the other hand, if it is determined that the generation of the reference image is not selected, the process proceeds to step S5. The details of the reference image generation processing in step S4 will be described later.

In step S5, it is determined whether or not a mask image is generated. When it is determined that the generation of the mask image is selected, in step S6, the moire image determination process of selecting a moire image having a moire area from the input image held in the input image holding unit 604 of the image storage unit 6 is executed. In the next step S7, a mask image generation process for generating a mask image for excluding the moire regions of the reference image and the input image of the disc D from the effective pixels for discriminating the authenticity of the disc D is executed. .. After the mask image generation process of step S7 is completed, the process returns to step S2. On the other hand, if it is determined that the mask image generation is not selected, the process returns to step S2. Details of the moire image determination processing in step S6 and the mask image generation processing in step S7 will be described later.

In step S8, a genuine/counterfeit discriminating process for discriminating the authenticity of the disc D is executed. After the authenticity determination process of step S8 is completed, the process returns to step S2. The details of the authenticity determination process in step S8 will be described later.

Next, the reference image generation process of step S4 of FIG. 4 will be described with reference to FIG. In step S11, "1" is set to the disk number i (i=1). In other words, the disc number i of the disc D is initialized. In the next step S12, the rotation angle θ is set to “0” (θ=0). In other words, the rotation angle θ is initialized.

In the next step S13, a captured image acquisition process for acquiring a captured image of either the front surface or the back surface of the disc D is executed. The image acquisition unit 2 images the disk D that has reached the imaging position, in other words, the disk D facing the imaging window 33, and acquires a captured image of the disk D. The image acquisition unit 2 outputs the acquired captured image to the control unit 4 as a captured image data ID. The control unit 4 transfers the supplied captured image data ID to the image storage unit 6. The image storage unit 6 stores and holds the picked-up image based on the sent picked-up image data ID in the picked-up image holding unit 600. The details of the captured image acquisition process in step S13 will be described later.

Next, proceeding to step S14, the preprocessing unit 500 executes preprocessing on the captured image of the disk D. The control unit 4 outputs the storage unit control signal MCS to the image storage unit 6, and the image storage unit 6 outputs the captured image data ID based on the captured image held in the captured image holding unit 600 based on the storage unit control signal MCS. Output to the processing unit 500. The preprocessing unit 500 performs preprocessing on the captured image based on the transmitted captured image data ID. The preprocessing unit 500 outputs the preprocessed image as the processed image data PD to the processed image holding unit 602 of the image storage unit 6. The details of the preprocessing in step S14 will be described later.

Next, in step S15, it is determined whether the disc number i exceeds 1 (i>1) (i≦1). When the disk number i is 1 or less (i≦1), in other words, when the disk number i is “1” (i=1), in other words, in the reference image generation process of step S4 of FIG. If the disk D from which the image acquisition unit 2 has acquired the captured image is the first disk, the process proceeds to step S16. On the other hand, if the disk number i exceeds 1 (i>1), in other words, if the disk D from which the image acquisition unit 2 has acquired the captured image is the second disk or later, the process proceeds to step S21.

In the next step S16, the input image holding unit 604 of the image storage unit 6 holds the input image of the disc D having the disc number “1”. The pre-processing unit 500 outputs the pre-processed captured image (pre-processed image) of the disc D having the disc number “1” to the input image holding unit 604 as the input image data BD. The input image holding unit 604 stores and holds the input image based on the sent input image data BD in association with the disc number i. In step S16, the input image holding unit 604 stores and holds the input image based on the sent input image data BD in association with the disc number "1". In other words, the input image holding unit 604 stores and holds the input image based on the sent input image data BD as the input image of the disc number “1”.

In the next step S17, the reference image holding unit 606 of the image storage unit 6 holds the reference image of the disc D. The pre-processing unit 500 outputs the pre-processed captured image (pre-processed image) of the disc D having the disc number “1” to the reference image holding unit 606 as the reference image data RD. The reference image holding unit 606 stores and holds the reference image of the disc D based on the sent reference image data RD. Each of the input image data BD output by the preprocessing unit 500 in step S16 and the reference image data RD output by the preprocessing unit 500 in step S17 is based on the preprocessed image of the disc D having the same disc number "1". The data. In other words, at the time of step S17, the same image is held in the input image holding unit 604 and the reference image holding unit 606. In other words, at the time of step S17, the input image of the disc number “1” held in the input image holding unit 604 and the reference image held in the reference image holding unit 606 are the same image.

In the next step S18, the image rotation unit 514 of the reference image generation unit 510 creates a plurality of reference images by rotating the reference image for each predetermined rotation angle difference θd. The reference image storage unit 606 outputs the reference image data RD to the reference image generation unit 510. The image rotation unit 514 of the reference image generation unit 510 performs rotation processing for rotating the image on the reference image based on the sent reference image data RD. The image rotation unit 514 rotates the reference image for each predetermined rotation angle difference θd with the center position of the disk D as the rotation center, and creates a plurality of reference images. The reference image generation unit 510 outputs the plurality of reference images rotated by the image rotation unit 514 to the reference image holding unit 606 as reference image data RD. The reference image holding unit 606 stores and holds each of the plurality of reference images based on the sent reference image data RD in association with the rotation angle θ. The rotation angle difference θd can be set arbitrarily. For example, when the rotation angle difference θd is “1 degree”, the rotation angle difference θd is rotated by “1 degree”, that is, the rotation angle θ is different by “1 degree”. 360 reference images are created. When the rotation angle difference θd is “3.6 degrees”, 100 reference images with different rotation angles θ of “3.6 degrees” are created. Further, when the rotation angle difference θd is “5 degrees”, 72 reference images having different rotation angles θ of “5 degrees” are created. Details of the image rotation process in step S18 will be described later.

In the next step S19, "i+1" is set to the disk number i. In other words, the value obtained by adding "1" to the current disc number i is set as the new disc number i. In other words, the disk number i is updated.

In the next step S20, it is determined whether or not the disc number i exceeds a preset value imax (i>imax). In other words, it is determined whether the disc number i has reached the total number imax of the discs D set in advance for generating the reference image. If the disc number i is equal to or less than the value imax (i≦imax), the process returns to step S12 and the reference image generation process is continued. On the other hand, when the disc number i exceeds the value imax (i>imax), the process proceeds to step S25.

If the disk number i exceeds "1" (i>1) in step S15, the process proceeds to step S21. In the next step S21, the comparison determination unit 512 of the reference image generation unit 510 determines whether or not the preprocessed image of the disc number i matches the reference image. The reference image storage unit 606 outputs the reference image data RD to the reference image generation unit 510. The processed image storage unit 602 outputs the preprocessed image data PD to the reference image generation unit 510. The comparison determination unit 512 of the reference image generation unit 510 compares the reference image based on the sent reference image data RD with the preprocessed image of the disc number i based on the sent preprocessed image data PD, and compares it with the reference image. The dissimilarity of the preprocessed image is calculated, and it is determined whether the preprocessed image matches the reference image based on the calculated dissimilarity. In other words, the comparison determination unit 512 determines whether the disk D with the disk number i matches the disk D with the disk numbers “1” to “i−1”. When it is determined that the preprocessed image of the disc number i matches the reference image, the process proceeds to step S22. On the other hand, when it is determined that the pre-processed image of the disc D does not match the reference image, that is, the reference image does not match, the process returns to step S12, and the process of the next disc D is executed. The details of the comparison determination process in step S21 will be described later.

In the next step S22, the input image holding unit 604 holds the input image of the disc number i. The reference image generation unit 510 outputs the preprocessed image of the disc number i to the input image holding unit 604 as the input image data BD. The input image holding unit 604 stores and holds the input image based on the sent input image data BD in association with the disc number i.

In the next step S23, the image integration section 516 of the reference image generation section 510 integrates the reference image with the input image of the disk number i. The reference image storage unit 606 outputs the reference image data RD to the reference image generation unit 510. The input image storage unit 604 outputs the input image data BD to the reference image generation unit 510. The image integration unit 516 of the reference image generation unit 510 compares the input image of the disk number i based on the input image data BD sent with respect to the reference image of the rotation angle “0 degrees” based on the supplied reference image data RD. Add up.

In the next step S24, the reference image holding unit 606 holds the reference image. The reference image generation unit 510 outputs the reference image after image integration as the reference image data RD to the reference image holding unit 606. The reference image holding unit 606 stores and holds the reference image based on the sent reference image data RD as the reference image of the rotation angle “0 degree”. After the reference image holding unit 606 stores and holds the reference image after the image integration, the process proceeds to step S19.

If the disc number i is greater than or equal to imax in step S19 (i≧imax), the process proceeds to step S25, and the image rotation unit 514 rotates the reference image with the rotation angle “0 degrees” at each predetermined rotation angle difference θd. Create multiple reference images. The reference image storage unit 606 outputs the reference image data RD to the reference image generation unit 510. The image rotation unit 514 of the reference image generation unit 510 performs rotation processing for rotating the image on the reference image having the rotation angle “0 degrees” based on the sent reference image data RD. The image rotation unit 514 rotates the reference image of the rotation angle “0 degree” for each predetermined rotation angle difference θd with the center position of the disc D as the rotation center, and creates a plurality of reference images. The reference image generation unit 510 outputs the plurality of reference images rotated by the image rotation unit 514 to the reference image holding unit 606 as reference image data RD. The reference image holding unit 606 stores and holds each of the plurality of reference images based on the sent reference image data RD in association with the rotation angle θ. The image rotation process in step S25 is exactly the same as the image rotation process in step S18. When the image rotation process in step S25 is completed, the reference image generation process ends. In this way, the reference image generation process of step S4 of FIG. 4 is completed, and a plurality of input images associated with each disc number i, that is, each of the disc numbers “1” to “imax”, is input image holding unit 604. Are held in the reference image holding unit 606. The input image holding unit 604 stores and holds the input image associated with each disk number i, and the reference image holding unit 606 stores and holds the reference image associated with each rotation angle θ. It returns to step S5 of 4.

In the present embodiment, in the reference image generation process of step S3 of FIG. 4, the input image is added to the reference image of the rotation angle θ held in the reference image holding unit 606 of the image storage unit 6 in the image integration process of step S23. However, it is also possible to sequentially integrate each of the input images of the disc numbers “2” to “imax” with respect to the input image of the disc number “1”. Further, in the comparison determination process of step S21, the matching determination of the preprocessed images of the disc numbers “3” to “imax” is performed on the reference image obtained by integrating the input images of the disc numbers “1” to “i-1”. Although it is performed, it is also possible to hold the preprocessed image of the disc number “1” as a temporary reference image and perform the matching determination of the preprocessed image of the disc number i based on the temporary reference image.

The captured image acquisition process of step S13 of FIG. 5 will be described with reference to FIG. In step S31, it is determined whether or not the image pickup timing sensor 3 is turned on. In other words, it is determined whether or not the disc D moving on the disc transport path 31 has reached the imaging position. When the disc D reaches the image pickup position, the image pickup timing sensor 3 is turned on. That is, the imaging timing sensor 3 is turned on in response to the movement of the disc D in the disc transport path 31. If the imaging timing sensor 3 is on, the process proceeds to step S32. When the disk D has not reached the image pickup position, the image pickup timing sensor 3 is kept in the off state, and step S31 is repeatedly executed. In other words, the image acquisition unit 2 is in a standby state until the disc D reaches the imaging position.

In the next step S32, the control unit 4 outputs the lighting control signal LCS to the light emitting element 22, and the light emitting element 22 is lit for a short time (that is, flash is issued) based on the lighting control signal LCS. As a result, diffused light is emitted from the light projecting device 11 toward the imaging window 33, and the disk D facing the imaging window 33 is projected.

In the next step S33, the control unit 4 outputs the image pickup control signal ICS to the image pickup element 42, and the image pickup element 42 picks up an image of the disc D to be discriminated based on the image pickup control signal ICS. In other words, the captured image of the disc D to be discriminated is acquired by the two-dimensional imaging device 12. The image sensor 42 outputs the acquired captured image data ID to the control unit 4. The control unit 4 transfers the supplied captured image data ID to the image storage unit 6. The image storage unit 6 stores and holds the picked-up image based on the sent picked-up image data ID in the picked-up image holding unit 600. After the captured image acquisition process of step S13 of FIG. 5 is completed in this way, the process returns to step S14 of FIG.

The preprocessing of step S14 of FIG. 5 will be described with reference to FIG. In step S41, the edge extraction unit 502 executes edge extraction processing on the captured image held in the captured image holding unit 600. The edge-extracted image is held in the processed image holding unit 602 of the image storage unit 6.

In the next step S42, the center extracting unit 504 extracts the center position of the disk D in the image after edge extraction held in the processed image holding unit 602. The coordinate value of the extracted center position is stored in a storage area (not shown) of the image storage unit 6.

In the next step S43, the image cutout unit 506 cuts out the image after edge extraction held in the processed image holding unit 602 into a rectangular shape. The image cutout unit 506 cuts out the image after edge extraction into a rectangular shape based on the center position of the disk D extracted by the center extraction unit 504. More specifically, the image cutout unit 506 cuts out the image after edge extraction into a rectangular shape so that the intersection of two rectangular diagonal lines matches the center position of the disk D. The image cut out in a rectangular shape is held in the processed image holding unit 602. In this way, the preprocessing of step S14 of FIG. 5 is completed, and the captured image subjected to the preprocessing is held in the processed image holding unit 602 as a processed image. After the processed image holding unit 602 stores and holds the processed image, the process returns to step S15 in FIG.

The image rotation processing of steps S18 and S25 of FIG. 5 will be described with reference to FIG. First, in step S51, “θ+θd” is set as the rotation angle θ. In other words, the value obtained by adding the rotation angle difference θd to the current rotation angle θ is set as the new rotation angle θ. In other words, the rotation angle θ is updated.

In the next step S52, it is determined whether or not the rotation angle θ is 360 degrees or more (θ≧360 degrees). When the rotation angle θ is not 360 degrees or more (θ<360 degrees), the process proceeds to step S53.

In the next step S53, the image rotation unit 514 of the reference image generation unit 510 rotates the reference image corresponding to the rotation angle 0 degrees (θ=0) held in the reference image holding unit 606 by the rotation angle θ. The reference image rotated by the rotation angle θ (hereinafter referred to as the reference image with the rotation angle θ) is held in the reference image holding unit 606. After the reference image holding unit 606 stores and holds the reference image of the rotation angle θ, the process returns to step S51, and the image rotation process is continued.

On the other hand, when the rotation angle θ is 360 degrees or more (θ≧360 degrees) in step S52, it is determined that the creation of the reference image rotated for each rotation angle difference θd is completed, and the rotation of step S18 in FIG. The image creation process is completed. In this way, the rotation reference image generation process of step S18 of FIG. 5 is completed, and each reference image rotated by the rotation angle difference θd is held in the reference image holding unit 606 as the reference image of the rotation angle θ. After the reference image holding unit 606 stores and holds the reference image of each rotation angle θ, the process returns to step S19 of FIG. Further, the rotation reference image generation process of step S25 of FIG. 5 is completed, and each reference image rotated by the rotation angle difference θd is held in the reference image holding unit 606 as the reference image of the rotation angle θ. After the reference image holding unit 606 stores and holds the reference image of each rotation angle θ, the reference image generation process of FIG. 5 is completed.

The reference image comparison determination process in step S21 of FIG. 5 will be described with reference to FIG. First, in step S61, the reference image generation unit 510 corrects the relative positional deviation (rotational angle deviation and horizontal deviation) of the preprocessed image of the disk D having the disk number i with respect to the reference image. The correction of the relative positional deviation can be performed, for example, by the method of correcting the rotational angle deviation and the horizontal deviation disclosed in Japanese Patent Laid-Open No. 2016-134073. The processed image storage unit 602 of the image storage unit 6 outputs the preprocessed image data PD to the reference image generation unit 510 of the image processing unit 5. The reference image storage unit 606 of the image storage unit 6 outputs the reference image data RD to the reference image generation unit 510 of the image processing unit 5. The reference image generation unit 510 compares the preprocessed image of the disc number i based on the sent preprocessed image data PD with the reference image based on the sent reference image data RD to compare the preprocessed image of the disc number i before the reference image. Correct the relative displacement of the processed image. The comparison determination unit 512 of the reference image generation unit 510 compares the preprocessed image of the disc number i with the reference image of each rotation angle θ, and compares the preprocessed image of the disc number i with the reference image of the rotation angle “0°”. Derive the deviation angle. The image rotation unit 514 of the reference image generation unit 510 rotates the preprocessed image of the disc number i by the derived shift angle θ. The contrast determination unit 512 corrects the horizontal displacement of the pre-processed image in which the rotational angle displacement has been corrected, with respect to the reference image having the rotational angle of “0 degrees”. The preprocessed image of the disk number i whose relative positional deviation has been corrected in this way is stored and held in the processed image holding unit 602.

In the next step S62, the comparison determination unit 512 calculates the dissimilarity DF of the preprocessed image of the disc number i in which the relative displacement with respect to the reference image is corrected. The processed image storage unit 602 outputs the preprocessed image data PD to the reference image generation unit 510. The reference image storage unit 606 outputs the reference image data RD to the reference image generation unit 510. The reference image generation unit 510 compares the preprocessed image of the disc number i based on the sent preprocessed image data PD with the reference image of the rotation angle “0 degree” based on the sent reference image data RD, The difference DF of the preprocessed image of the disc number i with respect to the reference image is calculated. The calculated difference DF is stored in a storage area (not shown) of the image storage unit 6.

In the next step S63, it is determined whether the dissimilarity DF is less than or equal to a predetermined threshold. If the difference DF is equal to or less than the threshold value (DF≦threshold value), the process proceeds to step S64, and the preprocessed image of the disc number i matches the reference image, in other words, the preprocessed image of the disc number i is the reference image. It is determined that the image is an image to be integrated into, and the process returns to step S22 in FIG. On the other hand, when the difference DF exceeds the threshold (DF>threshold), the process proceeds to step S65, and the reference image and the preprocessed image of the disc number i do not match, in other words, the preprocessed image of the disc D is the reference image. It is determined that the image is not an image to be integrated in step S13, and the process returns to step S13 in FIG.

Next, the moire determination processing in step S6 of FIG. 4 will be described with reference to FIGS. 10 and 11. First, in step S81, "1" is set to the disk number i. In other words, the disk number i is initialized.

In the next step S82, the moiré image processing unit 520 reads out the reference image held in the reference image holding unit 606. In the next step S83, the moire image processing unit 520 reads the input image of the disc number i held in the input image holding unit 604.

In the next step S82, the evaluation value derivation unit 522 of the moire image processing unit 520 compares the input image of the disc number i with the reference image to derive the evaluation value EV. As the evaluation value EV, for example, the degree of difference or the degree of coincidence of the input image with respect to the reference image can be used. Further, as the evaluation value EV, for example, the number of pixels (the number of pixels) of the input image which is different from the reference image can be simply used. The derived evaluation value EV is stored in a storage area (not shown) of the image storage unit 6.

In the next step S85, "i+1" is set to the disk number i. In other words, the value obtained by adding "1" to the current disc number i is set as the new disc number i. In other words, the disk number i is updated.

In the next step S86, it is determined whether or not the disk number i exceeds a preset value imax (i>imax). If the disk number i is imax or less (i≦imax), the process returns to step S83. On the other hand, if the disc number i exceeds imax (i>imax), the process proceeds to step S87.

In the next step S87, the judgment threshold value setting unit 524 of the moire image processing unit 520 sets the judgment threshold value DI for judging whether or not the input image has a moire area, in other words, whether or not the input image is a moire image. To do. The determination threshold value DI is set from the frequency distribution based on the evaluation value EV. More specifically, the determination threshold value DI is set based on the frequency distribution on the side where the evaluation value is higher than the average value of the frequency distribution based on the evaluation value EV. After the determination threshold setting unit 524 sets the determination threshold DI, the process proceeds to step S88 in FIG. The set determination threshold value DI is stored in a storage area (not shown) of the image storage unit 6.

In the next step S88, the disc number i is set to "1", and the moire image number j (hereinafter referred to as the moire number j) is set to "1". In other words, the disc number i and the moire number j are initialized.

In the next step S89, the moire image selection unit 526 reads out the determination threshold value DI stored in the storage area (not shown) of the image storage unit 6. In the next step S90, the moire image selection unit 526 reads out the evaluation value EV of the disk number i stored in the storage area (not shown) of the image storage unit 6.

In the next step S91, it is determined whether the evaluation value EV of the disc number i is equal to or less than the determination threshold value DI. The moire image selection unit 526 compares the evaluation value EV of the disc number i with the determination threshold value DI, and determines whether the input image of the disc number i has a moire region, in other words, the disc number i based on the size relationship. It is determined whether the input image is a moire image. If the evaluation value EV of the disc number i is less than or equal to the determination threshold DI, the process proceeds to step S92, and it is determined that the input image of the disc number i has a moire area, in other words, the input image of the disc number i is a moire image. , And proceeds to step S93. On the other hand, when the evaluation value EV of the disc number i exceeds the determination threshold value DI, the process proceeds to step S98, the input image of the disc number i does not have a moire area, in other words, the input image of the disc number i is not a moire image. Then, the process proceeds to step S96.

In step S93, the moire image holding unit 608 of the image storage unit 6 stores and holds the moire image with the moire number j. The moire image processing unit 520 outputs the input image of the disk number i, which is determined by the moire image selection unit 526 to have the moire area, to the moire image holding unit 608 as the moire image data MD. The moire image holding unit 608 stores and holds the moire image based on the sent moire image data MD as the moire image with the moire number j.

In the next step S94, the moire number j is set to "j+1". In other words, the value obtained by adding "1" to the current moire number j is set as the new moire number j. In other words, the moire number j is updated.

In the next step S95, the maximum moire number jmax is set to "j". In other words, the maximum moire number jmax is updated.

In the next step S96, the disk number i is set to "i+1". In other words, the value obtained by adding "1" to the current disc number i is set as the new disc number i. In other words, the disk number i is updated.

In the next step S97, it is determined whether or not the disc number i exceeds a preset value imax (i>imax). In other words, in the reference image generation process of FIG. 5, it is determined whether or not the total number imax of the disks D stored and held in the input image holding unit 604 is exceeded. If the disk number i is imax or less (i≦imax), the process returns to step S90. On the other hand, when the disc number i exceeds imax (i>imax), it is determined whether or not there is a moire area for all the input images of the disc number i held in the input image holding unit 604, in other words, a moire image. If the determination as to whether or not it is completed is made, the moire image determination is ended. In this way, the moire image determination processing in step S6 of FIG. 4 is completed, and each input image of the disc number i that is determined to be a moire image is held in the moire image holding unit 608 as a moire image of the moire number j. .. After the moire image holding unit 608 stores and holds the moire image, the process returns to step S7 in FIG.

The mask image generation processing in step S7 of FIG. 4 will be described with reference to FIGS. 12 and 13. First, in step S121, the moire number j is set to "1". In other words, the moire number j is initialized.

In the next step S122, the moire image holding unit 608 stores and holds the integrated moire image. The moire image holding unit 608 of the image storage unit 6 outputs the moire image data MD based on the moire image of the moire number j to the moire image processing unit 520. The moire image processing unit 520 outputs the moire image with the moire number j based on the sent moire image data MD to the moire image holding unit 608 as the integrated moire image data IMD. The moire image holding unit 608 stores and holds the integrated moire image based on the sent integrated moire image data IMD. In other words, the moire image with the moire number j is held in the moire image holding unit 608 as an integrated moire image. In other words, in step S122, the moire image having the moire number “1” is held in the moire image holding unit 608 as an integrated moire image.

In the next step S123, the moire number j is set to "j+1". In other words, the value obtained by adding "1" to the current moire number j is set as the new moire number j. In other words, the moire number j is updated.

In the next step S124, the moire image integration unit 528 performs image integration processing on the integrated moire image and the moire image with the moire number j. The moire image holding unit 608 of the image storage unit 6 outputs the moire image data MD based on the integrated moire image data IMD and the moire image of the moire number j to the moire image processing unit 520. The moire image integration unit 528 performs image integration processing on the integrated moire image based on the sent integrated moire image data IMD and the moire image with the moire number j based on the sent moire image data MD. In other words, the moire image with the moire number j is added to the integrated moire image. The moire image processing unit 520 outputs the integrated moire image subjected to the image integration processing to the moire image holding unit 608 as the integrated moire image data IMD. The moire image holding unit 608 stores and holds the integrated moire image based on the sent integrated moire image data IMD.

In the next step S125, the moire number j is set to "j+1". In other words, the value obtained by adding "1" to the current moire number j is set as the new moire number j. In other words, the moire number j is updated.

In the next step S126, it is determined whether or not the moire number j exceeds the total number jmax of moire images on the disc D held in the moire image holding unit 608 (j>jmax). If the moire number j is equal to or smaller than jmax, the process returns to step S125, and the process of integrating the moire image with the moire number j to the integrated moire image is continued. On the other hand, when the moire number j exceeds jmax, the process proceeds to step S130 in FIG.

In the next step S127, the mask threshold setting unit 542 calculates the absolute value (difference pixel value) of the difference between the pixel values of each pixel of the reference image and the integrated moire image as difference information. The reference image holding unit 606 outputs the reference image data RD to the mask image processing unit 520. The moire image holding unit 608 outputs the integrated moire image data IMD to the mask image processing unit 520. The mask threshold setting unit 542 of the mask image processing unit 520 determines the absolute value of the difference between the pixel values of the respective pixels of the reference image based on the sent reference image data RD and the integrated moire image based on the integrated moire image data IMD (differential pixel Value) is calculated. The calculated difference information (difference pixel value of each pixel) is stored in a storage area (not shown) of the image storage unit 6.

In the next step S128, the mask threshold setting unit 542 sets the mask threshold MI. The mask threshold setting unit 542 sets the mask threshold MI based on the difference information between the reference image and the integrated moire image. In other words, the mask threshold setting unit 542 sets the mask threshold MI from the frequency distribution table for the difference pixel value of each pixel between the reference image and the integrated moire image. The set mask threshold MI is stored in a storage area (not shown) of the image storage unit 6.

In the next step S129, the mask image generation unit 544 binarizes the difference image based on the difference information between the reference image and the integrated moire image. In other words, the mask image generation unit 544 binarizes the difference image based on the difference pixel value of each pixel between the reference image and the integrated moire image. The mask image processing unit 540 outputs the binarized difference image to the mask image holding unit 610 as mask image data BMD. The mask image holding unit 610 stores and holds the mask image based on the sent mask image data BMD. In this way, the mask image generation process of step S7 of FIG. 4 is completed, and the mask image holding unit 610 stores and holds the mask image, and then the registration mode of the disc discriminating apparatus 1 of FIG. 4 ends.

The authenticity determination process of step S8 of FIG. 4 will be described with reference to FIG. First, in step S141, the rotation angle θ is set to “0 degrees”. In other words, the rotation angle θ is initialized.

In the next step S142, a captured image acquisition process for acquiring a captured image of either the front surface or the back surface of the disc D to be discriminated is executed. The image acquisition unit 2 captures an image of the disc D that is the determination target that has reached the imaging position, and acquires a captured image of the disc D. The image acquisition unit 2 outputs the captured image data ID based on the acquired captured image of the disc D to be discriminated to the control unit 4. The control unit 4 transfers the supplied captured image data ID to the image storage unit 6. The image storage unit 6 stores and holds the picked-up image of the disc D to be discriminated based on the sent picked-up image data ID in the picked-up image holding unit 600. This captured image acquisition processing is exactly the same as the captured image acquisition processing in step S13 of FIG. 5, and is executed in the flowchart of the captured image acquisition processing shown in FIG.

In the next step S143, the preprocessing unit 500 executes preprocessing on the captured image of the disc D to be discriminated. The control unit 4 outputs the storage unit control signal MCS to the image storage unit 6, and the image storage unit 6 is based on the captured image of the disc D to be discriminated, which is held in the captured image holding unit 600 based on the storage unit control signal MCS. The captured image data ID is output to the preprocessing unit 500. The pre-processing unit 500 performs pre-processing on the captured image of the disc D to be discriminated based on the transmitted captured image data ID. The pre-processing unit 500 outputs the pre-processed captured image of the disc D to be discriminated to the processed image holding unit 602 of the image storage unit 6 as pre-processed image data PD. The processed image holding unit 602 stores and holds the preprocessed image of the disc D to be discriminated based on the sent preprocessed image data PD as the discriminated image. This pre-processing is exactly the same as the pre-processing of step S14 of FIG. 5, and is executed in the flowchart of the pre-processing shown in FIG.

In the next step S144, the difference degree deriving unit 564 of the discriminating unit 560 discriminates the authenticity of the disc D to be discriminated. The dissimilarity deriving unit 564 compares the reference image and the discriminated image, and calculates the dissimilarity DF of the discriminated image with respect to the reference image. The dissimilarity deriving unit 564 determines the authenticity of the disc D to be discriminated based on the calculated dissimilarity DF. Details of the comparison determination process in step S145 will be described later. After the comparison determination process of step S145 is completed, the authentication determination process of step S8 of FIG. 4 ends.

The comparison determination process of step S145 of the authenticity determination process of FIG. 14 will be described with reference to FIG. First, in step S161, the dissimilarity derivation unit 564 of the determination unit 560 corrects the relative positional deviation of the determination target image with respect to the reference image. The relative positional deviation can be corrected by the method of correcting the rotational angle deviation and the horizontal deviation disclosed in, for example, Japanese Patent Laid-Open No. 2016-134073, similarly to the deviation correction processing in step S61 of FIG. 9 described above. The dissimilarity deriving unit 564 compares the reference image and the discriminated image and corrects the relative positional deviation of the discriminated image with respect to the reference image. The dissimilarity deriving unit 564 compares the discriminated image with the reference image at each rotation angle θ, and derives the shift angle of the discriminated image with respect to the reference image at the rotation angle “0 degrees”. The difference degree deriving unit 564 rotates the determined image by the derived shift angle θ. The dissimilarity deriving unit 564 corrects the horizontal shift of the discriminating image in which the rotation angle shift is corrected with respect to the reference image of the rotation angle “0 degrees”. In this way, the dissimilarity deriving unit 564 prepares the discriminated image in which the relative positional deviation with respect to the reference image of the rotation angle “0 degree” is corrected.

In the next step S162, the mask image application unit 562 of the determination unit 560 performs mask processing on each of the reference image and the determination target image. In other words, the mask image application unit 562 applies the mask image to each of the reference image and the discriminating image. In other words, the mask image application unit 562 performs the mask process on each of the reference image and the discriminating image with the rotation angle “0 degree”. The mask image holding unit 610 outputs the mask image data BMD to the determination unit 560. The mask image application unit 562 applies the mask image based on the sent mask image data BMD to each of the reference image and the image to be discriminated at the rotation angle “0 degree”.

In the next step S163, the dissimilarity deriving unit 564 determines the dissimilarity DF of the masked determination target image with respect to the masked reference image having the rotation angle of “0 degrees” (hereinafter referred to as the masked reference image). To calculate. The reference image generation unit 510 compares the masked reference image with the masked discriminating image, and calculates the difference DF of the masked discriminating image with respect to the masked reference image. The calculated difference DF is stored in a storage area (not shown) of the image storage unit 6.

In the next step S164, it is determined whether the dissimilarity DF is less than or equal to a predetermined threshold. When the difference DF is equal to or less than the threshold value (DF≦threshold value), the process proceeds to step S165, and it is determined (match determination) that the masked determination target image matches the masked reference image. In other words, it is determined that the disc D is a genuine disc. On the other hand, if the difference DF exceeds the threshold value (DF>threshold value), the process proceeds to step S166, and it is determined that the masked determination target image does not match the masked reference image (mismatch determination). In other words, the disc D is determined to be a fake disc. In this way, the authenticity determination process of the disc D to be determined in step S8 of FIG. 4 is completed, and the determination result is output from the image processing unit 5 to the control unit 4 as a determination signal IS. After the image processing unit 5 outputs the discrimination signal IS to the control unit 4, the discriminating mode of the disc discriminating apparatus 1 of FIG. 4 ends.

(Modification)
The present invention is not limited to the above embodiment, but various modifications can be made. In this embodiment, each time the reference image and the pre-processed image (discriminated image) of the disc D are compared, the mask image is combined with the reference image and the discriminated image. For example, step S7 in FIG. In the mask image generation process (1), it is possible to generate the mask image by the binarization process in step S132 of FIG. 12 and then perform the mask process on the reference image of the rotation angle “0 degree”. In that case, as shown in FIG. 15, after the mask image is generated in step S209, a mask process of applying the mask image to the reference image of the rotation angle “0 degree” held in the reference image holding unit 606 in step S210 is performed. Execute. Then, in step S162 of the comparison determination process of FIG. 14, the mask process is performed only on the non-determined image. Note that each processing of steps S201 to S209 of FIG. 15 is exactly the same as each processing of steps 121 to 129 of FIG. 13, and thus description thereof will be omitted. In this way, in the mask image generation process of step S7 of FIG. 4, by preparing the reference image that has been subjected to the masking process, every time the comparison determination process of step S145 of the authenticity determination process of FIG. It is not necessary to perform mask processing on the image, and the authenticity determination processing of step S8 in FIG. 4 can be efficiently executed.

Further, in the authenticity determination process of step S8 of FIG. 4, before the captured image acquisition process of step S142 of FIG. 13, the mask process of applying the mask image to the reference image of the rotation angle “0 degree” is performed. It is also possible. In that case, as shown in FIG. 16, mask processing is performed on the reference image in step S242 before the captured image acquisition processing in step S243. Then, in step S162 of the comparison determination process of FIG. 14, the mask process is performed only on the image to be discriminated. Note that the processing of steps S241, S243, and S244 in FIG. 16 is exactly the same as the processing of steps S141, S142, and S143 in FIG. In this way, by preparing the reference image that has been masked in advance before the captured image acquisition processing of step S243 of the authenticity determination processing of FIG. 16, the comparison determination of step S245 of FIG. 16 is efficiently executed. can do.

1 Disk Discriminating Device 2 Image Acquisition Unit 3 Imaging Timing Sensor 4 Control Unit 5 Image Processing Unit 6 Image Storage Unit 7 Input/Output I/F
8 Status Indicator 9 Discrimination Criteria Storage Unit 11 Light Emitting Device 12 Two-Dimensional Imaging Device 21 Surface Emitting Device 22 Light Emitting Element 23 Light Guide Plate 24 Reflective Sheet 25 Diffusing Sheet 26 Half Mirror 31 Disk Conveying Path 32 Base Plate 33 Imaging Window 34 Transparent Light plate 35 Imaging area 41 Condensing lens 42 Imaging element 500 Pre-processing unit 502 Edge extraction unit 504 Center extraction unit 506 Image cutout unit 510 Reference image generation unit 512 Comparison determination unit 514 Image rotation unit 516 Image integration unit 520 Moire image processing 522 Evaluation value derivation unit 524 Judgment threshold setting unit 526 Moire image selection unit 528 Moire image integration unit 540 Mask image processing unit 542 Mask threshold setting unit 544 Mask image generation unit 560 Judgment unit 562 Mask image application unit 564 Dissimilarity derivation unit 600 Captured image storage unit 602 Processed image storage unit 604 Input image storage unit 606 Reference image storage unit 608 Moire image storage unit 610 Mask image storage unit D Disk ID Captured image data BD Input image data RD Standard image data PD Processed image data MD Moire image Data IMD Integrated moire image data BMD Mask image data DL Conveyance direction ICS Imaging control signal IS Discrimination signal LCS Lighting control signal TS Timing signal MCS Storage unit control signal PCS Image processing control signal SS Status notification instruction signal SLS Discrimination reference data DF Dissimilarity EV Evaluation value DI Judgment threshold MI Mask threshold

Claims (8)

A disc discriminating device for discriminating the authenticity of the disc to be discriminated by comparing the discriminated image corresponding to the disc to be discriminated and the reference image by excluding and comparing the moire regions from the effective pixels,
A reference image generation unit that integrates a plurality of input images corresponding to each of a plurality of discs to be discriminated as a genuine disc, and generates the reference image;
A moiré image selection unit that selects, from the plurality of input images, a plurality of moiré images having the moiré region based on a comparison result between each of the plurality of input images and the reference image,
A mask image generation unit that generates a mask image that excludes the moiré region from effective pixels based on a comparison result between the accumulated moiré image obtained by integrating the plurality of moiré images and the reference image;
A discriminating unit which discriminates the authenticity of the disc to be discriminated by applying the mask image and comparing the inputted discriminated image and the reference image.
Disc discriminating apparatus including. An evaluation value derivation unit that derives an evaluation value of matching for the reference image for each of the plurality of input images,
A determination threshold value setting unit that sets a determination threshold value of the moire image from the frequency distribution of the plurality of evaluation values derived by the evaluation value derivation unit,
Further equipped with,
The disk discriminating apparatus according to claim 1, wherein the moire image selection unit selects the moire image by making a determination on each of the evaluation values of the plurality of input images based on the determination threshold. The disk discriminating apparatus according to claim 2, wherein the determination threshold value setting unit sets the determination threshold value based on the frequency distribution on the side where the evaluation value is higher than the average value of the frequency distribution. The mask image generation unit uses a value that maximizes the degree of separation in the frequency distribution of the difference pixel values between the integrated moire image and the reference image as a threshold value, and the difference image between the integrated moire image and the reference image is binary. The disc discriminating apparatus according to any one of claims 1 to 3, wherein a masked image is used as the masked image. A disc discriminating method of a disc discriminating device for discriminating the authenticity of the disc to be discriminated by comparing a discriminated image corresponding to the disc to be discriminated and a reference image by excluding and comparing a moire area from effective pixels,
And as the reference image generation factory for generating the reference image by integrating a plurality of input images corresponding to each of a plurality of disks to be discriminated as genuine disc,
A higher moire image selection Engineering for selecting from among said plurality of respectively the reference image and a plurality of moire image the plurality of input images having the moire on the basis of a comparison result of the input image,
And as the mask image generation factory for generating the mask image to exclude the moire from effective pixels based on the comparison result of the accumulated moire image obtained by integrating the plurality of moire image and the reference image,
And the input has been the object determination image and the reference image as discrimination Engineering to determine the authenticity of the determination target disk by comparing by applying the mask image,
A disc discriminating method of a disc discriminating apparatus comprising : And as the evaluation value deriving engineering to derive the evaluation value of the matching with respect to the reference image for each of the plurality of input images,
From the frequency distribution of the plurality of the evaluation value derived in extent the evaluation value deriving Engineering as determination threshold setting factory that sets the determination threshold for the moire image,
Further equipped with,
In extent the moire image selection Engineering, disk discriminating method for a disk discriminating device according to claim 5 for selecting the moire image by determining based on the determination threshold value for each of the evaluation values of the plurality of input images. Wherein the determination threshold setting Engineering degree, disk discriminating method for a disk discriminating device according to claim 6 configured to set the determination threshold value based on the frequency distribution of the frequency distribution mean the evaluation value is higher than the value side. Two in the mask image generation Engineering degree, as a threshold value for degree of separation is maximized in the frequency distribution of the differential pixel values between the reference image and the accumulated moire image, a difference image between the reference image and the accumulated moire images The disc discriminating method of the disc discriminating apparatus according to claim 5, wherein a binarized image is used as the mask image.

Images