JP2019175320A - Disk image acquisition device and disk discrimination device - Google Patents

Abstract

To enable the outline to be detected reliably even when the disk reflectance is reduced, and to enable contamination of a transparent part to be easily detected.SOLUTION: A disk image acquisition device includes: a transparent part having a support surface that supports one surface of a disk; a background part having a surface opposed to the support surface forming a background region outside the outline of the disk; an illumination part that emits illumination light onto the one surface of the disk; and an imaging device that receives reflected light from the one surface of the disk. The illumination part emits illumination light at least including a first color component and a second color component having a different wavelength from the first color component. The background part is configured to reflect the illumination light of the first color component, and to absorb the illumination light of the second color component. When a disk exists, the imaging device receives reflected light from the one surface of the disk and the background region to acquire a first captured image corresponding to reflected light of the first color component and a second captured image corresponding to reflected light of the second color component, and when a disk does not exist, receives reflected light from the background part to acquire a third captured image corresponding to the first color component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a disk image acquisition device, and more specifically, captures an image of one surface of a disk, acquires a captured image, and compares a discriminated image generated based on the captured image with a reference image to determine the authenticity of the disk. The present invention relates to a disc image acquisition device used for discrimination. More specifically, the present invention relates to a disc image acquisition device for reliably detecting the contour of a disc in a captured image and easily detecting dirt on a transparent portion that supports one surface of the disc.

  The present invention also relates to a disc discrimination device, and more specifically, obtains a captured image by imaging one surface of the disc, and compares the discriminated image generated based on the captured image with a reference image to determine the authenticity of the disc. The present invention relates to a disc discrimination device for discriminating discs. More specifically, the discriminating accuracy is improved by reliably detecting the contour of the disc in the captured image, and the contamination of the transparent portion that supports one surface of the disc can be easily detected, improving the convenience of maintenance work. The present invention relates to a disc discriminating apparatus capable of performing the above.

  Note that the disc in this specification is a concept that includes medals and tokens used in gaming machines, and coins as currency.

  When capturing images of the front or back surface of a disc such as medals or coins (hereinafter collectively referred to as “front surface”) and determining the denomination or authenticity using the captured image, the contour of the disc in the captured image is usually displayed. To detect. A material that absorbs almost all of the light (in other words, has a very low reflectivity) is applied to the member located on the opposite side of the surface of the disk to be imaged. For example, in the “token image acquisition device” of Patent Document 1, a token image acquisition device in which a token that slides and moves on a base is imaged by an imaging device that is relatively arranged based on the base, and imaging information is acquired. An imaging base portion facing the imaging device is formed of dark resin. Thereby, it is said that the brightness of the imaging base part which is a background falls remarkably and the clear outline of a token can be obtained.

  A technique for detecting dirt on a transparent passage surface through which a disk passes has been proposed. For example, in the “object contour reading device” of Patent Document 2, an illumination unit that irradiates illumination light from the back to the path surface of an object, an image sensor that captures an image of light transmitted around the object, In an object outline reading device equipped with means for reading the outline of an object from an output signal, means for determining the presence or absence of dirt adhering to the currency surface of the object from the output signal of the image sensor, and detecting dirt continuously for a certain period of time And a means for outputting a warning when there is a failure. As a result, if there is dirt on the passage surface before passing the object while waiting for the object to pass the passage surface, it is removed by detecting that the dirt has adhered for a certain period of time. It is supposed that it is possible to detect dirt to be detected. In addition, as an object, it is supposed that the insertion coin in a vending machine corresponds, for example.

  Furthermore, a technique for acquiring a captured image of a disk surface located on a transparent member using a surface light source and a half mirror has been proposed. For example, in the “coin identification device” of Patent Document 3, as an “imaging unit”, a surface light source that emits illumination light that illuminates the surface of a coin passing on a transparent member with a constant output, and the surface of the coin is reflected. Imaging means for receiving the reflected light, and a beam splitter disposed at a location where the illumination light emitted from the surface light source and the reflected light incident on the imaging means intersect. The illumination light emitted from the surface light source is incident on the surface of the coin via the beam splitter, and the reflected light reflected on the surface of the coin is incident on the imaging means via the beam splitter. Thereby, an imaging means images the surface of a coin.

JP 2009-163298 A (FIG. 4, claims 1, 0082, 0083) JP-A-4-217091 (FIGS. 1 to 6, claims 1, 0011 to 0018) JP 2012-212221 A (FIGS. 1 to 3, Claims 1, 0015 to 0025)

  In general, when a disc such as a medal or a coin is used for a long period of time, the surface state may change due to contamination, alteration, wear, or the like, and the reflectivity on the disc surface may decrease. In that case, as disclosed in the “token image acquisition device” of Patent Document 1, when the background is configured by a member having a very low reflectance such as dark resin, the reflected light from the background is in a disk with a significantly reduced reflectance. Therefore, there is a problem that it is difficult to detect the contour of the disk.

  Further, since the technique disclosed in the “object outline reading device” in Patent Document 2 detects passage dirt using transmitted light, the “imaging unit” in Patent Document 3 that receives reflected light with an imaging unit. It cannot be applied to. Further, when the technique disclosed in the “token image acquisition device” in Patent Literature 1 is applied to the “imaging unit” in Patent Literature 3, the amount of light received by the imaging means is significantly reduced, so that dirt is detected. There is a problem that it becomes difficult.

  The present invention has been made in view of the above-described problems, and its object is to reliably detect the contour of the disc even when the reflectivity of the disc surface is reduced due to long-term use, An object of the present invention is to provide a disk image acquisition device that can easily detect dirt on a transparent portion that supports one surface of a disk.

  In addition, when the reflectivity of the disc surface decreases due to long-term use, the disc contour is reliably detected to improve the discrimination accuracy and easily detect dirt on the transparent part that supports one side of the disc. Therefore, it is possible to provide a disk discriminating apparatus capable of improving the convenience of maintenance work.

  Other objects of the present invention which are not specified here will be apparent from the following description and the accompanying drawings.

  In order to achieve this object, the disc image acquisition device and disc discriminating device according to the present invention are configured as follows.

  (1) The first disc image acquisition device of the present invention is disposed on the other side of the disc supported by the support surface, the transparent portion having a support surface that supports one surface of the disc, and the support A background portion having a surface opposite to a surface, the surface forming a background region outside the contour of the disk when the disk exists on the support surface, and the disk supported by the support surface; An illumination unit that irradiates illumination light to the background part through the transparent part; and an imaging device that receives the reflected light from one surface of the disk and the background part that is transmitted through the transparent part. And the background portion irradiates the illumination light including at least a first color component and a second color component having a wavelength different from that of the first color component, and the background portion reflects the illumination light of the first color component and the first color component. Absorbs illumination light of two color components The imaging device receives reflected light from one surface of the disk and the background area when the disk is on the support surface, and corresponds to the reflected light of the first color component. A first captured image and a second captured image corresponding to the reflected light of the second color component are acquired, and when the disk does not exist on the support surface, the reflected light from the background portion is received and the first captured image is received. It is a disk image acquisition apparatus which acquires the 3rd captured image corresponding to the reflected light of a color component.

  In the first disc image acquisition device of the present invention, one surface of the disc (hereinafter referred to as “disc surface”) is supported by the support surface of the transparent portion, and the background portion is disposed on the other surface side of the disc. The background portion has a surface facing the support surface of the transparent portion, and the surface forms a background region outside the contour of the disk. The illumination unit irradiates the disk surface and the background portion with illumination light including at least a first color component and a second color component having a wavelength different from that of the first color component via the transparent portion. Reflected light from the disk surface and the background portion passes through the transparent portion and is received by the image sensor. The background portion is configured to reflect the illumination light of the first color component and absorb the illumination light of the second color component. The image sensor receives reflected light from the disk surface and the background area when the disk is on the support surface of the transparent portion, and receives the first captured image and the second color component corresponding to the reflected light of the first color component. A second captured image corresponding to the reflected light is acquired.

  When the reflectance of the disk surface is significantly reduced, the illumination light of the first color component is absorbed by the disk surface and reflected by the background area. Thereby, the reflected light of the first color component becomes minute on the disk surface and remains constant in the background area. For this reason, in the first captured image, there are a pixel area with a very low brightness corresponding to the disk surface and a pixel area with a high brightness corresponding to the background area. Therefore, even if the disk has a low reflectivity, the contour of the disk can be reliably detected by using the first captured image. On the other hand, when the reflectance of the disk surface is high, the illumination light of the second color component is reflected by the disk surface and absorbed by the background area. Thereby, the reflected light of the second color component is large on the disk surface and small in the background area. Therefore, in the second captured image, there are a high-luminance pixel area corresponding to the disk surface and a minute-luminance pixel area corresponding to the background area. Therefore, even in the case of a high reflectivity disc, the contour of the disc can be detected more reliably by using the second captured image.

  Further, the imaging device receives reflected light from the background portion when the disk is not on the support surface of the transparent portion, and acquires a third captured image corresponding to the reflected light of the first color component. In this case, the third captured image becomes a high-luminance pixel region over the entire image. Therefore, it is possible to easily detect a region where the luminance is reduced due to the contamination of the transparent portion. Therefore, even when the reflectivity of the disc surface is lowered due to long-term use, the contour of the disc can be reliably detected and the contamination of the transparent portion can be easily detected.

  (2) In a preferred example of the first disc image acquisition device of the present invention, at least the surface of the background portion is colored in the same color as the first color component or an approximate color. In this case, there is an advantage that can be realized with a simple and inexpensive configuration.

  (3) In another preferred example of the first disk image acquisition device of the present invention, the background portion is configured such that the reflection of the first color component in the background region is specular reflection. In this case, since the reflectance in the background area can be increased, there is an advantage that the contour of the disc can be detected more reliably.

  (4) In still another preferred example of the first disk image acquisition device of the present invention, the background portion includes a mirror covered with a transparent member colored in the same color as the first color component or an approximate color. . In this case, there is an advantage that can be realized with a simple and inexpensive configuration.

  (5) In still another preferred example of the first disc image acquisition device of the present invention, the first color component is red and the second color component is blue. In this case, since the difference in wavelength between the first color component and the second color component is large, the luminance difference between the pixel area corresponding to the disk surface and the pixel area corresponding to the background area is large, and the disk is more reliably connected. There is an advantage that the contour can be detected.

  (6) The second disk image acquisition device of the present invention is disposed on the other surface side of the disk supported by the support surface, the transparent portion having a support surface that supports one surface of the disk, and the support A background portion having a surface opposite to a surface, the surface forming a background region outside the contour of the disk when the disk exists on the support surface, and the disk supported by the support surface; An illumination unit that irradiates illumination light to the background part through the transparent part; and an imaging device that receives the reflected light from one surface of the disk and the background part that is transmitted through the transparent part. The first illumination component of the first color component and the second illumination light of the second color component having a wavelength different from that of the first color component, and the background portion of the first illumination light of the first color component. And the second color component of the second color component is reflected. The imaging device is configured to absorb illumination light, and the imaging device receives reflected light from one surface of the disk and the background region when the disk is on the support surface, and reflects the reflected light of the first color component. The first captured image corresponding to the second captured image and the second captured image corresponding to the reflected light of the second color component are acquired, and the reflected light from the background portion is received when the disk does not exist on the support surface. And a disk image acquisition device that acquires a third captured image corresponding to the reflected light of the first color component.

  In the second disk image acquisition device of the present invention, one surface of the disk (hereinafter referred to as “disk surface”) is supported by the support surface of the transparent portion, and the background portion is disposed on the other surface side of the disk. The background portion has a surface facing the support surface of the transparent portion, and the surface forms a background region outside the contour of the disk. The illumination unit irradiates the disk surface and the background part with the first illumination light of the first color component and the second illumination light of the second color component having a wavelength different from that of the first color component through the transparent part. Reflected light from the disk surface and the background portion passes through the transparent portion and is received by the image sensor. The background portion is configured to reflect the first illumination light of the first color component and absorb the second illumination light of the second color component. The image sensor receives reflected light from the disk surface and the background area when the disk is on the support surface of the transparent portion, and receives the first captured image and the second color component corresponding to the reflected light of the first color component. A second captured image corresponding to the reflected light is acquired.

  When the reflectance of the disk surface is significantly reduced, the first illumination light of the first color component is absorbed by the disk surface and reflected by the background area. Thereby, the reflected light of the first color component becomes minute on the disk surface and remains constant in the background area. For this reason, in the first captured image, there are a pixel area with a very low brightness corresponding to the disk surface and a pixel area with a high brightness corresponding to the background area. Therefore, even if the disk has a low reflectivity, the contour of the disk can be reliably detected by using the first captured image. On the other hand, when the reflectance of the disk surface is high, the second illumination light of the second color component is reflected by the disk surface and absorbed by the background area. Thereby, the reflected light of the second color component is large on the disk surface and small in the background area. Therefore, in the second captured image, there are a high-luminance pixel area corresponding to the disk surface and a minute-luminance pixel area corresponding to the background area. Therefore, even in the case of a high reflectivity disc, the contour of the disc can be detected more reliably by using the second captured image.

  Further, the imaging device receives reflected light from the background portion when the disk is not on the support surface of the transparent portion, and acquires a third captured image corresponding to the reflected light of the first color component. In this case, the third captured image becomes a high-luminance pixel region over the entire image. Therefore, it is possible to easily detect a region where the luminance is reduced due to the contamination of the transparent portion. Therefore, even when the reflectivity of the disc surface is lowered due to long-term use, the contour of the disc can be reliably detected and the contamination of the transparent portion can be easily detected.

  (7) In a preferred example of the second disk image acquisition device of the present invention, at least the surface of the background portion is colored in the same color as the first color component or an approximate color. In this case, there is an advantage that can be realized with a simple and inexpensive configuration.

  (8) In another preferred example of the second disk image acquisition device of the present invention, the background portion is configured such that the reflection of the first color component in the background region is specular reflection. In this case, since the reflectance in the background area can be increased, there is an advantage that the contour of the disc can be detected more reliably.

  (9) In still another preferred example of the second disk image acquisition device of the present invention, the background portion includes a mirror covered with a transparent member colored in the same color as the first color component or an approximate color. . In this case, there is an advantage that can be realized with a simple and inexpensive configuration.

  (10) In still another preferred example of the second disk image acquisition device of the present invention, the first color component is red and the second color component is blue. In this case, since the wavelength difference between the first color component and the second color component is large, the luminance difference between the pixel area corresponding to the disk surface and the pixel area corresponding to the background area becomes large, and the contour of the disk is more reliably ensured. There is an advantage that can be detected.

  (11) The disc discriminating apparatus of the present invention includes a disc image acquiring device that captures an image of one surface of a disc to acquire a captured image, a discriminated image generated based on the captured image acquired by the disc image acquiring device, and a predetermined image. And a discriminating unit that discriminates the authenticity of the disc by comparing with the reference image of the disc, wherein the disc image acquisition device is the disc according to any one of (1) to (10). An image acquisition device, and a contour detection unit for detecting the contour of the disc for each of the first and second captured images acquired by the disc image acquisition device; and the disc image acquisition device The disc discrimination device further includes a dirt detection unit that detects dirt adhering to the transparent part based on a third captured image.

  In the disc discriminating apparatus according to the present invention, the disc image acquisition device includes any one of the above-described disc image acquisition devices (1) to (10). For this reason, as described in (1) and (6) above, the disc contour can be reliably detected even when the reflectivity of the disc surface is lowered due to long-term use, and the disc discrimination accuracy is increased. Further, since the dirt on the transparent portion that supports one surface of the disk can be easily detected from the captured image, the convenience of maintenance work is improved.

  According to the disk image acquisition device of the present invention, the contour of the disk can be reliably detected even when the reflectivity of the disk surface is lowered due to long-term use, and the contamination of the transparent part supporting one surface of the disk can be easily performed. The effect that it can detect is acquired.

  According to the disc discriminating apparatus of the present invention, it is possible to improve the discriminating accuracy by reliably detecting the contour of the disc even when the reflectivity of the disc surface decreases due to long-term use, and supports one side of the disc. As a result, it is possible to easily detect the contamination of the transparent portion, and the convenience of maintenance work can be improved.

It is a schematic sectional drawing which shows the disc image acquisition apparatus of 1st Embodiment of this invention. FIGS. 2A and 2B are schematic diagrams of images acquired by the disk image acquisition apparatus of FIG. 1, in which FIG. FIGS. 2A and 2B are schematic diagrams of an image with red pixels acquired by the disk image acquisition apparatus of FIG. 1, in which FIG. 1A is an image when there is no dirt, and FIG. It is a schematic block diagram which shows the disc discrimination | determination apparatus to which the disc image acquisition apparatus of FIG. 1 is applied. FIG. 5 is a block diagram illustrating an image processing unit of the disk discrimination device of FIG. 4. FIGS. 5A and 5B are schematic diagrams showing images generated by preprocessing in the disc discrimination device of FIG. 4, in which FIG. 4A shows an edge-enhanced image, FIG. 4B shows an image in which an effective area is set, and FIG. An image, (D) is an image subjected to mask processing. 6 is a flowchart showing the operation of the disk discrimination device of FIG. It is a flowchart which shows the detail of the stain | pollution | contamination detection step of FIG. It is a flowchart which shows the detail of the registration step of FIG. 10 is a flowchart showing details of pre-processing steps in FIGS. 7 and 9. It is a flowchart which shows the detail of the contrast determination step of FIG. FIG. 12 is a flowchart showing details of the comparison determination step in FIG. 7 and is a continuation of FIG. It is a flowchart which shows the detail of the parallel movement step of FIG. It is a schematic diagram which shows the movement of the image in the parallel movement step of FIG. It is a schematic sectional drawing which shows the disc image acquisition apparatus of 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the disc image acquisition apparatus of 3rd Embodiment of this invention.

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

(First embodiment)
FIG. 1 shows a disc image acquisition device 1 according to a first embodiment of the present invention. The disk image acquisition device 1 has a function of acquiring a captured image of the front surface or the back surface (hereinafter, referred to as “front surface” generically) of the disk D transported in the disk transport path 40. The disk image acquisition device 1 is disposed corresponding to the imaging window 44 opened in the base plate 42 and includes an illumination unit 10, an imaging unit 20, a beam splitter 30, and a background unit 50.

  The imaging window 44 defines an imaging area 46 of the disc D being conveyed. The imaging window 44 is rectangular in plan view, and has a pair of long sides that are substantially parallel to the transport direction DL of the transported disk D and a pair of short sides that are substantially perpendicular to the transport direction DL. In the imaging window 44, a transparent plate 48 having a support surface 48a that supports one surface Ds1 of the disk D is disposed. The support surface 48 of the transparent plate 48 is substantially flush with the surface of the base plate 42, in other words, the bottom surface of the disk transport path 40. The length of the pair of long sides of the imaging window 44 is set larger than the diameter of the disk D. This is because information regarding the diameter of the disk D in the longitudinal direction of the imaging window 44 is acquired. The short sides of the image pickup window 44 are arranged so that the straight line connecting the midpoints of the short sides of the image pickup window 44 and the trajectory of the center of the disc D being conveyed substantially coincide. This is because the information on the one surface Ds1 of the disk D is surely acquired.

  The illumination unit 10 has a function of irradiating illumination light onto the surface Ds1 of the disk D that moves in the disk transport path 40. The illumination unit 10 is, for example, a surface illumination unit 11 parallel to the surface Ds1 of the disk D. This is because the use of the surface illumination unit 11 enables imaging without the influence of shadows even if the rotational phase of the disk D is different. The surface illumination unit 11 includes a light emitting element 12, a light guide plate 14, a reflection sheet 16, and a diffusion sheet 18. In the present embodiment, the light emitting element 12 is an LED (Light Emitting Diode).

  The light emitting element (that is, LED) 12 is a light source for irradiating the disc D with illumination light. White LED is used for the light emitting element 12, and the light emitting element 12 irradiates white visible light. However, a three-color LED can also be used as the light emitting element 12. In any case, the illumination light includes a red component, a green component, and a blue component. As shown in FIG. 1, the light emitting element 12 is disposed so as to face the side end surface of the light guide plate 14. Therefore, the light emitting element 12 can be disposed in a plane parallel to the disk transport path 40, and the installation space is small. Note that the position of the light emitting element 12 shown in FIG. 1 is shown for convenience.

  In the present embodiment, the light guide plate 14 has a rectangular thin plate shape made of resin from the viewpoint of low cost, and the surface thereof is arranged in parallel to the disk transport path 40. The resin exhibits a milky white color due to the transparent or diffusing material. When the diffusion material is mixed, the diffusion sheet 18 becomes unnecessary. The light guide plate 14 can also be constituted by a glass substrate. In the present embodiment, the light guide plate 14 is opposed to the imaging region 46.

  The reflection sheet 16 has a function of preventing light from diffusing from the light guide plate 14 to the opposite side of the disk transport path 40 and reflecting it to the disk transport path 40 side. The reflection sheet 16 is in close contact with the surface of the light guide plate 14 located on the opposite side of the disk conveyance path 40. Note that a silver film may be deposited on the light guide plate 14 instead of the reflective sheet 16.

  The diffusion sheet 18 has a function of uniformly diffusing light irradiated from the surface of the light guide plate 14 on the disk conveyance path 40 side. Therefore, the irradiation light from the light emitting element 12 guided by the light guide plate 14 or reflected by the reflection sheet 16 is made a uniform amount of light over the entire surface by the diffusion sheet 18 and irradiated toward the disk transport path 40. Is done. As a result, the disk D is illuminated uniformly. The illumination light irradiated from the diffusion sheet 18 is irradiated at a right angle to the disk transport path 40, in other words, the disk D moving through the disk transport path 40. This is because an optical shadow due to the unevenness of the surface Ds1 of the disk D is not created. Since the light guide plate 14, the reflection sheet 16, and the diffusion sheet 18 are thin, the surface illumination unit 11 can be reduced in size.

  In addition, although the surface illumination part 11 of this embodiment is comprised including LED as the light emitting element 12, the light guide plate 14, the reflective sheet 16, and the diffusion sheet 18, it is not limited to this. For example, an LED array in which a plurality of LEDs are arranged two-dimensionally, or parallel light combining a point light source such as an LED and a lens can be used. In the present embodiment, an LED is used as the light emitting element 12, but the present invention is not limited to this, and a light source such as a cold cathode ray tube or a halogen lamp can also be used.

  The beam splitter 30 has a function of reflecting part of incident light and transmitting part of incident light. Specifically, the illumination light from the surface illumination unit 11 is transmitted and the reflected light from the surface Ds1 of the disk D is reflected. In other words, the beam splitter 30 irradiates illumination light from the surface illumination unit 11 at a right angle to the surface Ds1 of the disk D in the disk transport path 40, and reflects light from the surface Ds1 of the disk D to the disk transport path. Reflected in a direction parallel to 40 (in other words, a direction parallel to the surface Ds1 of the disk D). The beam splitter 30 in this embodiment is a half mirror 32. The half mirror 32 is formed by depositing or plating chromium as a reflective film on organic glass formed of a transparent resin having a thin rectangular plate shape. However, without being limited thereto, optical glass such as borosilicate glass, quartz glass, zirconia, ruby and sapphire may be used as the substrate glass instead of organic glass. Further, as the reflective film, 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 instead of chromium. The half mirror 32 is disposed at an angle of 45 degrees with respect to the surface of the disk transport path 40 (in other words, the imaging window 44) on the side of the imaging area 46. In the present embodiment, a half mirror 32 is used as the beam splitter 30. However, instead of the half mirror 32, a pair of right-angle prisms are joined, and the joined surface is coated with a dielectric multilayer film or a metal thin film. A prism can also be used.

  The imaging unit 20 includes a condenser lens 22 and an imaging element 24. The condenser lens 22 has a function of condensing the light reflected by the half mirror 32 onto the imaging surface of the imaging element 24. The condenser lens 22 is a convex lens having a predetermined refractive index, and is disposed in the vicinity of the image sensor 24 between the half mirror 32 and the image sensor 24. By disposing the condenser lens 22 in the vicinity of the image sensor 24, the condenser lens 22 can be reduced in size. The imaging element 24 has a function of capturing an image condensed by the condenser lens 22. The imaging element 24 is disposed on the opposite side of the half mirror 32 with respect to the condenser lens 22 and at a position where the surface image of the disk D is formed via the condenser lens 22. For the image pickup device 24, a CCD image sensor or a CMOS image sensor is adopted for miniaturization. The image sensor 24 is a color image sensor including a red pixel group, a green pixel group, and a blue pixel group. Of the light reflected by the half mirror 32, the red pixel group receiving the red component outputs a red captured image. The green pixel group receiving the green component outputs a green captured image, and the blue pixel group receiving the blue component outputs a blue captured image. In other words, the image sensor 24 acquires a red captured image corresponding to the red component, acquires a green captured image corresponding to the green component, and acquires a blue captured image corresponding to the blue component.

  The background portion 50 has a plate shape parallel to the base plate 42 and is disposed so as to face the imaging window 44 on the other surface Ds2 side of the disc D. The background unit 50 covers at least the imaging window 44 from above. The gap d between the background portion 50 and the base plate 42 is set to be slightly wider than the thickness of the disk D. Thereby, the movement of the disk D in the disk conveyance path 40 is performed smoothly. The background unit 50 is configured to reflect the red component of the illumination light emitted from the surface illumination unit 11 and absorb the blue component of the illumination light. Here, the red component is light having a wavelength of 610 nm to 780 nm, and the blue component is light having a wavelength of 430 nm to 460 nm. In the present embodiment, the base body 52 located at the top in FIG. 1, a mirror 54 disposed on the lower surface of the base body 52, and a colored transparent member 56 covered on the lower surface of the mirror 54 are configured. The The surface 50a facing the surface Ds2 of the disk D of the background portion 50 (in other words, the support surface 48a of the transparent portion 48) forms the background region BR outside the periphery (in other words, the contour) De of the disk D. .

  The mirror 54 is obtained by depositing or plating silver or aluminum as a reflective film on a surface 54b of the transparent thin base material 54a facing the base body 52. As the substrate 54a, optical glass such as organic glass, borosilicate glass, quartz glass, zirconia, ruby and sapphire, and transparent resin such as polycarbonate are used. However, the mirror 54 is not limited to this, and a glossy metal plate such as stainless steel can also be used.

  The colored transparent member 56 is made of a transparent resin colored in red. As the transparent resin, acrylic, polycarbonate, polyethylene terephthalate, or the like can be used. As the colorant, a material that selectively transmits the red component of the illumination light emitted from the surface illumination unit 11 is used.

  By configuring the background unit 50 as described above, the illumination light emitted from the surface illumination unit 11 is specularly reflected by the mirror 54, and the reflected light of the red component is reflected by the imaging element 24 of the imaging unit 20 via the half mirror 32. Received light. In other words, reflected light of a red component having a relatively high luminance can be obtained in the background region BR.

  FIG. 2 shows a captured image acquired by the imaging unit 20. FIG. 2A is a red picked-up image (hereinafter referred to as “R image”) acquired by a red pixel group, and the right half is a disk D having a low reflectance of the surface Ds1 (hereinafter “low reflectance disk Drl”). The left half is the case of the disk D having a high reflectivity of the surface Ds1 (hereinafter referred to as “high reflectivity disk Drh”). FIG. 2B is a blue captured image (hereinafter referred to as “B image”) acquired by the blue pixel group. Like FIG. 2A, the right half is the case of the low reflectance disk Drl, and the left Half is the case of the high reflectivity disk Drh.

  As shown in FIG. 2A, in the R image, the luminance of the pixel region RC2 corresponding to the surface Ds1 of the low reflectance disk Drl is low, and the luminance of the pixel region RB2 corresponding to the background region BR is high. . The luminance difference (in other words, the contrast ratio) between the pixel region RC2 and the pixel region RB2 is sufficiently ensured, and the contour De can be reliably detected. On the other hand, although the luminance of the pixel region RC1 corresponding to the surface Ds1 of the high reflectivity disk Drh is high and the luminance of the pixel region RB1 corresponding to the background region BR is low, the luminance difference between the pixel region RC1 and the pixel region RB1. (In other words, the contrast ratio) is lower than that of the low reflectance disk Drl.

  As shown in FIG. 2B, in the B image, the luminance of the pixel region BC1 corresponding to the surface Ds1 of the high reflectivity disk Drh is high, and the luminance of the pixel region BB1 corresponding to the background region BR is low. . The luminance difference (in other words, the contrast ratio) between the pixel area BC1 and the pixel area BB1 is sufficiently secured, and the contour De can be reliably detected. On the other hand, the luminance of the pixel region BC2 corresponding to the surface Ds1 of the low reflectivity disk Dr1 and the pixel region BB2 corresponding to the background region BR are both low, and the luminance difference between the pixel region BC2 and the pixel region BB2 (in other words, the contrast ratio). ) Is extremely low, it is difficult to detect the contour De.

  From the above, by detecting the contour for each of the R image and the B image, the contour De can be reliably detected in both the high reflectivity disk Drh and the low reflectivity disk Drl. Even in the case of the disc D having a reflectivity between the high reflectivity disc Drh and the low reflectivity disc Drl, it is possible to detect the contour of each of the R image and the B image, so that the contrast ratio is slightly lowered. Therefore, the contour De can be reliably detected.

  Next, a case where dirt is attached to the transparent plate 48 will be described. FIG. 3A shows an R image when an image is taken in a state where the disk D does not exist on the transparent plate 48. As shown in FIG. 3A, the luminance of the R image is high throughout. FIG. 3B shows an R image when dirt is attached to the transparent plate 48. In FIG. 3B, a dirt region DR corresponding to the attached dirt exists in the R image. In the dirt region DR, the pixel value is lowered as the transmittance of the transparent plate 48 is lowered, and a luminance difference is generated between the surrounding area of the dirt region DR. In other words, luminance unevenness occurs due to the dirt region DR in the R image. By comparing this luminance unevenness with a predetermined threshold value, the dirt region DR can be detected.

  Next, the disc discrimination device 100 using the disc image acquisition device 1 according to the present embodiment will be described with reference to FIG. The disc discriminating device 100 includes the disc image acquisition device 1 in FIG. F) 110, a status indicator 112, and a mode switch 114.

  The imaging timing sensor 102 has a function of detecting the timing at which the disk D conveyed on the disk conveyance path 40 passes over the imaging area 46. The imaging timing sensor 102 outputs a timing signal TS indicating the timing at which the disk D can be optimally imaged to the control unit 104 when almost the entire surface Ds1 of the disk D reaches above the imaging area 46.

  The control unit 104 controls the operation of the imaging element 24 of the imaging unit 20 and the light emitting element 12 of the illumination unit 10 based on the timing signal TS output from the imaging timing sensor 102, and the captured image signal output from the imaging element 24. It has a function of receiving the IS to determine the authenticity of the disk D and outputting the determination result to the input / output interface 110. The control unit 104 includes, for example, a microcomputer 122 that operates based on a predetermined program. The control unit 104 includes an image processing unit 124 that executes various image processes. Details of the image processing unit 124 will be described later.

  The EEPROM 106 has a function of storing a program and data for operating the control unit 104. As shown in FIG. 4, the EEPROM 106 includes a reference image holding unit 132 that holds a later-described reference image.

  The RAM 108 has a function of temporarily storing data necessary during the operation of the control unit 104. As shown in FIG. 4, the RAM 108 includes a captured image holding unit 134 that holds a captured image of the disk D imaged by the imaging device 24, and a processed image holding unit 136 that holds an image generated by the image processing unit 124. Is included.

  The input / output interface 110 has a function of electrically connecting to a main device (not shown) in which the disk discrimination device 100 is incorporated. By connecting the main device to the disc discriminating apparatus 100 via the input / output interface 110, a desired signal can be input / output to / from the main device.

  The status indicator 112 has a function of displaying the operation status of the disc discrimination device 100. The status indicator 112 is composed of, for example, a plurality of LEDs (not shown) having different emission colors, and the light emission of these LEDs is controlled by the control unit 104, whereby various statuses (for example, the disc identification device 100) (for example, Normal operation, error occurrence, etc.) are notified. As the status indicator 112, a display device such as a liquid crystal panel can be used.

  The mode switch 114 has a function of switching between a reference image registration mode and a discrimination mode, which will be described later. That is, when the mode changeover switch 114 is set to the registration mode, a process for registering the reference image using the reference disk SD serving as a reference for determination is executed. When the mode changeover switch 114 is set to the determination mode, a process for determining the authenticity of the determination target disk TD is executed.

  Next, the image processing unit 124, the EEPROM 106, and the RAM 108 of the control unit 104 will be described with reference to FIG. As shown in FIG. 5, the microcomputer 122, the EEPROM 106, and the RAM 108 constituting the control unit 104 are electrically connected via a bus line BL.

  First, the EEPROM 106 will be described. The EEPROM 106 includes a reference image holding unit 132. The reference image holding unit 132 has a function of holding a reference image generated in a registration mode described later. Since the reference image is an image serving as a reference for discriminating the authenticity of the disc D, it is necessary to always hold the disc in the discriminating operation and to rewrite the reference image as necessary. A rewritable nonvolatile memory is optimal. As will be described later, the reference image holding unit 132 holds a plurality of reference images having mutually different rotation angles and a plurality of reduced reference images obtained by reducing each of the plurality of reference images.

  The RAM 108 includes a captured image holding unit 134 and a processed image holding unit 136. The captured image holding unit 134 has a function of holding the captured image acquired by the imaging unit 20 of the disc image acquisition device 1. The processed image holding unit 136 has a function of temporarily holding a processed image that has been subjected to various types of processing by the image processing unit 124. The captured image holding unit 134 and the processed image holding unit 136 are preferably configured by the RAM 108 because the image is temporarily held and frequently read and written.

  Next, the image processing unit 124 of the control unit 104 will be described. The image processing unit 124 includes an edge enhancement unit 142, a contour detection unit 144, a center calculation unit 146, an effective area setting unit 148, a mask processing unit 150, a size conversion unit 152, an image rotation unit 154, an image movement unit 156, and a comparison determination unit. 158 and a dirt detection unit 160 are included.

  The edge enhancement unit 142 has a function of enhancing the edge of the captured image held in the captured image holding unit 134. Edge enhancement emphasizes a portion where the change in brightness is steep in the XY space. For example, by applying a known filter such as a Previt filter, a Sobel filter, a Roberts filter, or a Laplacian filter to the original image, an image with enhanced edges can be obtained. FIG. 6A shows an example of an edge-enhanced image. The captured image IR includes the entire contour De of the disk D. The processed image with the edge enhanced is held in the processed image holding unit 136. This edge enhancement is also called edge extraction.

  The contour detection unit 144 has a function of detecting the contour De for the processed image after edge enhancement held in the processed image holding unit 136. The contour De is detected by scanning in the X direction from the left side to the right side in the XY space in the image shown in FIG. 6 (A). It is assumed that the contour De. Also, the pixel whose pixel value finally becomes equal to or greater than a predetermined threshold is defined as the other contour De. By repeating this scanning in the X direction while shifting one pixel at a time downward in the Y direction, the contour De is detected over the entire target image. As described above, by detecting the contour De for each of the R image and the B image, the contour De can be reliably detected regardless of the reflectance of the surface Ds1 of the disk D. When the contour De is detected in both the R image and the B image, the contour De having the larger pixel value with respect to the predetermined threshold is adopted. The coordinate value of the detected contour De in the XY space is held in a storage area (not shown) of the RAM 108.

  The center calculation unit 146 has a function of calculating the center position of the disc in the captured image IR based on the contour De detected by the contour detection unit 144. In other words, the coordinate value indicating the center CP (see FIG. 6A) of the disk D in the captured image IR is calculated. A known method is used to calculate the center position. For example, one and the other of the contours De of the disk D are detected for each line extending in the vertical axis (Y-axis) direction in the captured image IR. The midpoint between both contours De in the line where the distance between the contours De is the maximum is set as the center position of the disk D. However, other methods can be used to extract the center position. The coordinate value of the center CP of the disk D is held in a storage area (not shown) of the RAM 108.

  The effective area setting unit 148 has a function of setting a valid area CR by extracting a predetermined pixel area set in advance in the XY space with the center coordinate obtained by the center calculation unit 146 as the center. As shown in FIG. 6B, the effective area CR is set by cutting out a square pixel area having a size including at least a part of the contour De of the disk D by a known method. The image of the effective area CR that has been cut out is held in the processed image holding unit 136 of the RAM 108.

  The mask processing unit 150 has a function of masking a portion other than a predetermined pixel region set in advance in the XY space in the effective region CR set by the effective region setting unit 148. By masking, the minimum value or the maximum value is set as the pixel value in the mask target area. As shown in FIG. 6C, the mask region MR is an outer region of a circle ML having a predetermined radius Rm with the center coordinate obtained by the center calculation unit 146 as the center CP. In this case, the radius Rm is set to be less than twice the one side of the effective region CR. Thereby, the contour De and the pixels located in the vicinity thereof are masked by the mask region MR. In this way, a mask processed image as shown in FIG. 6D is generated and held in the processed image holding unit 136 of the RAM 108.

  The size converter 152 has a function of reducing the image size (reducing the number of pixels) for a desired image. For the size conversion, a known method such as a bilinear method, a bicubic method, a nearest neighbor zero-order interpolation method, a four-point linear interpolation method, or a third-order convolution interpolation method is appropriately adopted, and is executed at a predetermined reduction rate with reference to the center CP. Is done. In the present embodiment, an image converted into a size of 1/3 in each of the X direction and the Y direction (in other words, a reduced image in which the number of pixels is reduced to 1/9) is generated.

  The image rotation unit 154 has a function of rotating a desired image in the XY space. The rotation is performed at a predetermined rotation angle using a known affine transformation with the center CP calculated by the center calculation unit 146 as a reference.

  The image moving unit 156 has a function of translating a desired image in the XY space. The parallel movement is performed in a predetermined direction and a moving distance using a known affine transformation. In other words, the entire image is translated based on the movement distance (for example, 1 pixel in the X axis direction and 0 pixel in the Y axis direction) indicated by the pixels.

  The comparison determination unit 158 compares pixel values for each pixel of the desired two images, and compares the pixel values based on the degree of difference between the two images (hereinafter referred to as the degree of difference) or the degree of coincidence (hereinafter referred to as the degree of coincidence). Has a function of determining whether or not the images match. For example, when determining by similarity, the correlation coefficient of the pixel value is obtained for each pixel, and the correlation coefficient is integrated to calculate the similarity. It is determined that the values match when the maximum similarity that maximizes the calculated similarity is equal to or greater than a predetermined threshold. When the determination is based on the difference degree, it is determined that the difference is the same when the minimum difference degree at which the difference degree is minimum is equal to or less than a predetermined threshold. In the present embodiment, the determination is made based on the similarity.

  The dirt detection unit 160 has a function of detecting the dirt region DR based on the R image acquired when the disk D is not present on the support surface 48a of the transparent plate 48. That is, when there is an edge having a pixel value equal to or greater than a predetermined threshold in the R image, it is determined that the stain on the transparent plate 48 has been detected.

  The edge enhancement unit 142, the contour detection unit 144, the center calculation unit 146, the effective area setting unit 148, the mask processing unit 150, the size conversion unit 152, the image rotation unit 154, the image moving unit 156, which constitute the image processing unit 124, The comparison determination unit 158 and the dirt detection unit 160 may be configured by either hardware or software as long as they have the respective functions. It is possible to make a part of the hardware and the rest software.

  Next, the operation of the disk discriminating apparatus 100 will be described with reference to FIGS.

  First, as shown in FIG. 7, initialization is performed in step S1. In the initialization, the frame rate of the image sensor 24, the sensitivity of the imaging timing sensor 102, and the like are set. As parameters, the number of pixels defining an effective area, a radius defining a mask area, and the like are set.

  In the next step S2, it is determined whether or not there is a stain detection request. That is, it is determined whether or not an interrupt signal for requesting contamination detection is input to the control unit 104 via the input / output interface 110. If it is determined that there is a stain detection request, the process proceeds to the next step S3, and the stain detection process of FIG. 8 is executed. If it is determined in step S2 that there is no dirt detection request, the process proceeds to step S4.

  In the stain detection process of FIG. 8, first, in step ST1, the control unit 104 outputs a lighting control signal LCS to the lighting unit 10, and the light emitting element (that is, LED) 12 is lit for a short time based on the lighting control signal LCS (that is, , Flash). Thereby, the illumination light which goes to the imaging window 44 from the illumination part 10 is emitted. At this time, since the disk D does not exist on the support surface 48 a of the transparent plate 48, illumination light is irradiated toward the surface 50 a of the background portion 50, and the illumination light is reflected by the mirror 54 of the background portion 50.

  In the next step ST2, the control unit 104 outputs an imaging control signal ICS to the imaging unit 20, and the imaging element 24 captures an image based on the imaging control signal ICS. In other words, a captured image of the surface 50a of the background portion 50 is acquired. The image sensor 24 outputs a captured image signal IS corresponding to the acquired captured image to the control unit 104. The control unit 104 stores the captured image based on the input captured image signal IS in the captured image holding unit 134 of the RAM 108.

  In the next step ST3, the edge enhancement unit 142 of the image processing unit 124 performs edge enhancement on the captured image held in the captured image holding unit 134. At this time, edge enhancement is performed on the R image of the captured images. The edge-enhanced R image is stored and held in the processed image holding unit 136 of the RAM 136.

  In the next step ST4, the presence or absence of luminance unevenness is determined. That is, it is determined whether or not there is an edge having a pixel value equal to or larger than a predetermined threshold in the R image after edge enhancement held in the processed image holding unit 136. If it is determined that there is an edge, the process proceeds to the next step ST5, and if it is determined that no edge exists, the process proceeds to step S4 in FIG. In step ST <b> 5 that is executed when it is determined that an edge is present, a dirt detection signal is output from the control unit 104. Thereby, for example, the status indicator 112 notifies that the transparent plate 48 is dirty. Thereafter, the process proceeds to step S4 in FIG.

  In step S4 of FIG. 7, it is determined whether or not to register a reference image. That is, it is determined whether or not the mode switch 114 is in the registration mode. If the mode switch 114 is in the registration mode, the process proceeds to step S5, and the registration process of FIG. 9 is executed. If the mode switch 114 is in the discrimination mode, the process proceeds to step S6.

  In the registration process of FIG. 9, first, registration is set in step S21. In the registration setting, various parameters relating to the reference disk SD to be registered are set. As the parameter, the number of surfaces of the reference disk SD is set. That is, when the front and back patterns are different, “2” is set as the number of faces of the reference disk SD. If the front and back patterns are the same, “1” is set as the number of sides of the reference disc SD. Here, it is assumed that “2” is set as the number of surfaces of the reference disk SD.

  In the next step S22, “1” is set to the face number k. In other words, the surface number k is initialized in step S22.

  In the next step S23, it is determined whether or not the imaging timing sensor 102 is turned on. In other words, it is determined whether or not the reference disc SD moving on the disc transport path 40 has reached the imaging position. When the reference disk SD reaches the imaging position, the imaging timing sensor 102 is turned on. That is, the imaging timing sensor 102 is turned on in response to the movement of the reference disk SD in the disk transport path 40. If the imaging timing sensor 102 is on, the process proceeds to step S24. If the reference disk SD does not reach the imaging position, the imaging timing sensor 102 is kept off and step S23 is repeatedly executed. In other words, the standby state is maintained until the reference disk SD reaches the imaging position.

  In the next step S24, the control unit 104 outputs a lighting control signal LCS to the illumination unit 10, and the light emitting element (that is, LED) 12 is turned on (that is, flashed) for a short time based on the lighting control signal LCS. Thereby, illumination light directed from the illumination unit 10 toward the imaging window 44 is emitted, and the reference light SD facing the imaging window 44 is irradiated with the illumination light.

  In the next step S25, the control unit 104 outputs an imaging control signal ICS to the imaging unit 20, and the imaging element 24 images the reference disk SD based on the imaging control signal ICS. In other words, the captured image of the reference disk SD is acquired by the disk image acquisition device 1. The image sensor 24 outputs a captured image signal IS corresponding to the acquired captured image to the control unit 104. The control unit 104 stores the captured image based on the input captured image signal IS in the captured image holding unit 134 of the RAM 108.

  In the next step S26, the image processing unit 124 generates the reference image by executing the preprocessing of FIG. 10 on the captured image held in the captured image holding unit 134. That is, in step S41 in FIG. 10, the edge enhancement unit 142 of the image processing unit 124 performs edge enhancement on the captured image held in the captured image holding unit 134. The edge-enhanced image is stored and held in the processed image holding unit 136 of the RAM 136. In subsequent step S42, the contour detection unit 144 of the image processing unit 124 detects the contour De in the edge-enhanced image. The detected coordinate value of the contour De is held in a storage area (not shown) of the RAM 108. In step S42, as described above, the contour De is detected for each of the R image and the B image. When the contour De is detected in both the R image and the B image, the contour De having a larger pixel value than the predetermined threshold is used.

  In next step S43, the center calculation unit 146 of the image processing unit 124 calculates the center position from the detected contour. The calculated coordinate value of the center position is held in a storage area (not shown) of the RAM 108. In subsequent step S44, the effective area setting unit 148 of the image processing unit 124 sets the effective area CR based on the center position calculated in step S43 in the edge-enhanced image held in the processed image holding unit 136 of the RAM 108. The image is cut out. The cut out image is held in the processed image holding unit 136 of the RAM 108. In step S <b> 45, the mask processing unit 150 of the image processing unit 124 executes mask processing on the cut-out image held in the processed image holding unit 136. In this way, the preprocessed image is held in the processed image holding unit 136 of the RAM 108 as a reference image. The coordinate value of the center position held in the RAM 108 is also associated with the reference image and held in a storage area (not shown) of the RAM 108. Thereafter, the process proceeds to step S27 in FIG.

  In step S27 of FIG. 9, “0” is set to the rotation angle θ. In other words, the rotation angle θ is initialized.

  In the next step S28, the reference image is stored. That is, the reference image held in the processed image holding unit 136 of the RAM 108 is held in the reference image holding unit 132 of the EEPROM 106. At this time, the reference image is held in the reference image holding unit 132 in association with the surface number k set in step S22 or S34 and the rotation angle θ set in step S27 or S31. In other words, the reference image is held so as to be selectable by designating the surface number k and the rotation angle θ. Further, the coordinate value of the center position of the reference image is also stored in a storage area (not shown) of the EEPROM 106 in association with the reference image.

  In the next step S29, a reduced reference image is generated. That is, the size conversion unit 152 of the image processing unit 124 reduces the reference image held in the processed image holding unit 136 of the RAM 108, thereby generating a reduced reference image. For example, the reduction ratio is set to 1/3 in each of the X-axis direction and the Y-axis direction. In this case, the total number of pixels is reduced to 1/9. In subsequent step S <b> 30, the reduced reference image generated in step S <b> 29 is stored in the reference image holding unit 132 of the EEPROM 106. At this time, as in the case of the reference image, the reduced reference image is associated with the surface number set in step S22 or step S34 and the rotation angle θ set in step S27 or S31, and the reference image holding unit 132. Retained. In other words, the reduced reference image is held so as to be selectable by designating the surface number k and the rotation angle θ.

  In the next step S31, “θ + θd” obtained by adding the rotation angle increment θd to the current rotation angle θ is set as a new rotation angle θ. In other words, the rotation angle θ is updated. In the present embodiment, the rotation angle increment θd is set so that a total of 100 images including “θ = 0” are obtained when the reference image and the reduced image to be discriminated are rotated once. In this case, the rotation angle increment θd is “3.6 °”. In a succeeding step S32, it is determined whether or not the rotation angle θ updated in the step S31 is “360 °” or more. If “θ <360 °”, the process proceeds to step S33, and if “θ ≧ 360 °”, the process proceeds to step S34.

  In step S33 executed when it is determined in step S32 that the rotation angle θ is less than “360 °” (that is, “θ <360 °”), the reference image is rotated. That is, the image rotation unit 154 of the image processing unit 124 rotates the reference image held in the processed image holding unit 136 of the RAM 108 by the rotation angle θ set in step S31. Thereafter, the process returns to step S28, and steps S28 to S33 are repeatedly executed. Thus, a plurality of reference images and a plurality of reduced reference images whose rotation angles θ are not less than “0 °” and less than “360 °” and have different rotation angles are held in the reference image holding unit 132 of the EEPROM 106.

  In step S34 executed when it is determined in step S32 that the rotation angle θ is equal to or greater than “360 °” (ie, “θ ≧ 360 °”), “1” is added to the current surface number k. k + 1 "is set as the new face number k. In other words, the surface number k is updated. In the following step S35, it is determined whether or not the surface number k updated in step S34 is “3” or more. If the surface number k is less than “3” (that is, “k <3”), the step is performed. Returning to S23, steps S23 to S33 are repeatedly executed. As a result, a plurality of reference images and a plurality of reduced reference images are held in the reference image holding unit 132 of the EEPROM 106 for each of both surfaces of the reference disk SD. On the other hand, if it is determined in step S35 that the face number k is “3” or more (that is, “k ≧ 3”), the registration mode processing is completed and the process returns to step S2 in FIG.

  In steps S6 to S14 executed when the mode changeover switch 114 is in the discrimination mode in step S4 of FIG. 7, a captured image of the discrimination target disk TD is acquired, and the authenticity of the discrimination target disk TD is determined based on the captured image. Determined. That is, in step S6, it is determined whether or not the imaging timing sensor 102 is turned on. In other words, it is determined whether or not the determination target disk TD moving on the disk transport path 40 has reached the imaging position. When the discrimination target disk TD reaches the imaging position, the imaging timing sensor 102 is turned on. That is, the imaging timing sensor 102 is turned on in response to the movement of the discrimination target disk TD in the disk transport path 40. If the imaging timing sensor 102 is on, the process proceeds to step S7. If the discrimination target disk TD does not reach the imaging position, the imaging timing sensor 102 is kept off and step S6 is repeatedly executed. In other words, the standby state is maintained until the discrimination target disk TD reaches the imaging position.

  In the next step S7, the control unit 104 outputs a lighting control signal LCS to the illumination unit 10, and the light emitting element (that is, LED) 12 is lighted (that is, flashed) for a short time based on the lighting control signal LCS. Thereby, illumination light directed from the illumination unit 10 toward the imaging window 44 is emitted, and illumination light is irradiated to the discrimination target disk TD facing the imaging window 44.

  In the next step S8, the control unit 104 outputs an imaging control signal ICS to the imaging unit 20, and the imaging element 24 images the discrimination target disk TD based on the imaging control signal ICS. In other words, the captured image of the discrimination target disk TD is acquired by the disk image acquisition device 1. The image sensor 24 outputs a captured image signal IS corresponding to the acquired captured image to the control unit 104. The control unit 104 stores the captured image based on the input captured image signal IS in the captured image holding unit 134 of the RAM 108.

  In the next step S <b> 9, the image processing unit 124 performs the preprocessing of FIG. 10 on the captured image held in the captured image holding unit 134 to generate a discrimination image. That is, in step S41 in FIG. 10, the edge enhancement unit 142 of the image processing unit 124 performs edge enhancement on the captured image held in the captured image holding unit 134. The edge-enhanced image is stored and held in the processed image holding unit 136 of the RAM 136. In subsequent step S42, the contour detection unit 144 of the image processing unit 124 detects the contour De in the edge-enhanced image. The detected coordinate value of the contour De is held in a storage area (not shown) of the RAM 108. In step S42, as described above, the contour De is detected for each of the R image and the B image. When the contour De is detected in both the R image and the B image, the contour De having a larger pixel value than the predetermined threshold is used.

  In next step S43, the center calculation unit 146 of the image processing unit 124 calculates the center position from the detected contour. The calculated coordinate value of the center position is held in a storage area (not shown) of the RAM 108. In subsequent step S44, the effective region setting unit 148 of the image processing unit 124 sets the effective region CR based on the center position calculated in step S43 in the edge-enhanced image held in the processed image holding unit 136 of the RAM 108. The image is cut out. The cut out image is held in the processed image holding unit 136 of the RAM 108. In step S <b> 45, the mask processing unit 150 of the image processing unit 124 executes mask processing on the cut-out image held in the processed image holding unit 136. In this way, the preprocessed image is stored and held in the processed image holding unit 136 of the RAM 108 as a discrimination image in step S10 of FIG.

  In the next step S11, a reduced discrimination image is generated. That is, the size conversion unit 152 of the image processing unit 124 reduces the discrimination target image held in the processing image holding unit 136 of the RAM 108, thereby generating a reduced discrimination target image. The reduction ratio is set to be the same as that when a reduced reference image is generated from the reference image. In the subsequent step S12, the reduced discrimination image generated in step S11 is stored and held in the processed image holding unit 136 of the RAM.

  In the next step S13, the comparison determination is performed by executing the processes in FIG. 11 and FIG. First, in step S51 of FIG. 11, “0” is set to the rotation angle θ. In other words, the rotation angle θ is initialized. In subsequent step S52, a reduced reference image having a rotation angle θ is selected from the plurality of reduced reference images held in the reference image holding unit 132 of the EEPROM 106.

  In the next step S53, the reduced reference image selected in step S52 is compared with the reduced image to be discriminated held in the processed image holding unit 136 of the RAM 108, and the similarity SM is calculated. The similarity SM is calculated by comparing pixel values for each pixel of the reduced reference image and reduced reduced image, obtaining a correlation coefficient of the pixel values in units of pixels, and integrating the correlation coefficients.

  In the next step S54, it is determined whether or not the rotation angle θ is “0”. When the rotation angle θ is “0” (that is, when “θ = 0”), the process proceeds to step S56, and when the rotation angle θ is not “0” (that is, when “θ ≠ 0”). Proceed to step S55. In step S56 and the next step S57, a maximum similarity SMm indicating the maximum value of the similarity SM and a maximum similarity rotation angle θm that maximizes the similarity SM are set. That is, the current similarity SM is set as the maximum similarity SMm in step S56, and the current rotation angle θ is set as the maximum similarity rotation angle θm in step S57. The set maximum similarity SMm and maximum similarity rotation angle θm are stored in a storage area (not shown) of the RAM 108. When “θ = 0” in step S54, the similarity SM calculated in step S53 is set as the maximum similarity SMm, and “0” is set as the maximum similarity rotation angle θm.

  If “θ ≠ 0” in step S54, it is determined in step S55 whether or not the similarity SM calculated in step S53 exceeds the maximum similarity SMm. When the similarity SM exceeds the maximum similarity SMm (that is, when “SM> SMm”), the process proceeds to step S56, and the calculated similarity SM is set as the maximum similarity SMm, whereby the maximum similarity SMm. Is updated. Further, in step S57, the current rotation angle θ is set to the maximum similarity rotation angle θm, whereby the maximum similarity rotation angle θm is updated. On the other hand, when the similarity SM is equal to or less than the maximum similarity SMm (that is, when “SM ≦ SMm”), the process proceeds to step S58, and the current maximum similarity SMm and the maximum similarity rotation angle θm are maintained.

  In the next step S57, “θ + θd” obtained by adding the rotation angle increment θd to the rotation angle θ is set as a new rotation angle θ. In other words, the rotation angle θ is updated. In a succeeding step S59, it is determined whether or not the rotation angle θ is “360 °” or more. When the rotation angle θ is less than “360 °” (that is, when “θ <360 °”), the process returns to step S52, and the processes of steps S52 to S59 are repeatedly executed. As a result, a comparison is made between a plurality of reduced reference images having different rotation angles θ and reduced reduced images including the case of “θ = 0”. In this way, the maximum similarity rotation angle θm, which is the approximate rotation angle shift amount of the reduced reference image with respect to the reduced discrimination image, is calculated. The calculated maximum similarity rotation angle θm is stored in a storage area (not shown) of the RAM 108. In step S59, when the rotation angle θ is “360 °” or more (that is, when “θ ≧ 360 °”), the process proceeds to step S61 in FIG. In this way, the processing speed can be increased by comparing the reduced reference image and the reduced image to be discriminated with a small number of pixels.

  In step S61 of FIG. 12, the reference image having the maximum similarity rotation angle θm held in the RAM 108 is selected from the plurality of reference images held in the reference image holding unit 132 of the EEPROM 106. In the subsequent step S62, "0" is set to the rotation angle count number i. In other words, the rotation angle count number i is initialized.

  In the next step S63, it is determined whether or not the rotation angle count number i is “0”. If “i = 0”, the process proceeds to step S68. If “i ≠ 0”, the process proceeds to step S64. In the next step S64, it is determined whether or not the rotation angle count number i is “1”. If “i = 1”, the process proceeds to step S65. After “−θs” is set as the rotation angle θ in step S65, the process proceeds to step S67. If “i ≠ 1”, the process proceeds to step S66. θs is a rotation angle fine adjustment amount, and in this embodiment, the rotation angle fine adjustment amount θs is “1 °”. In the next step S66, after “θs” is set as the rotation angle θ, the process proceeds to step S67.

  In the next step S67, the discriminated image held in the processed image holding unit 136 of the RAM 108 is rotated by the image rotating unit 154 of the image processing unit 124 at the rotation angle θ set in step S65 or S66. The image to be discriminated is rotated in the XY space with the center position of the image to be discriminated held in the RAM 108 as the center.

  In the next step S68, "0" is set to the image movement count number j. In other words, the image movement count number j is initialized. In subsequent step S69, the image to be discriminated is compared with the reference image, and the similarity SM is calculated. The similarity SM is calculated by comparing pixel values for each pixel of the reference image and the image to be discriminated, obtaining a correlation coefficient of the pixel values for each pixel, and integrating the correlation coefficients.

  In the next step S70, it is determined whether or not the similarity SM calculated in step S69 is greater than or equal to a predetermined threshold value. If the similarity SM is greater than or equal to the threshold value, the process proceeds to step S71, where it is determined that the image to be determined and the reference image compared in step S69 match, and the process proceeds to step S14 in FIG. On the other hand, if the similarity SM is less than the threshold, the process proceeds to step S72.

  In the next step S72, the image moving unit 156 of the image processing unit 124 translates the discriminated image on the XY section. The parallel movement is performed by executing the parallel movement process of FIG. In the parallel movement process of FIG. 13, the discriminated image selected in step S61 of FIG. 12 (that is, the discriminated image not rotated) and the discriminated image rotated in step S67 correspond to the image movement count number j. It is translated in a predetermined direction. That is, in step S81, it is determined whether or not the image movement count number j is “0”. If “j = 0”, the image to be determined is moved one pixel to the upper right in step S88 (the position of FIG. 14A). After the movement to P1, that is, each “+1” pixel movement in the X-axis direction and the Y-axis direction), the process proceeds to step S73 in FIG. If “j ≠ 0”, the process proceeds to step S82, where it is determined whether or not the image movement count number j is “1”. In the case of “j = 1”, the discriminated image is moved upward by one pixel in step S89 (moved to the position P2 in FIG. 14B, that is, moved by “+1” pixel in the Y-axis direction), then FIG. The process proceeds to step S73. If “j ≠ 1”, the process advances to step S83 to determine whether or not the image movement count number j is “2”. In the case of “j = 2”, the image to be discriminated is moved by one pixel in the upper left in step S90 (moved to position P3 in FIG. 14C, that is, “−1” in the X-axis direction and “+1” in the Y-axis direction. After the pixel movement), the process proceeds to step S73 in FIG. If “j ≠ 2”, the process proceeds to step S84 to determine whether or not the image movement count j is “3”. In the case of “j = 3”, the image to be discriminated is moved by one pixel to the left (moved to the position P4 in FIG. 14D, that is, “−1” pixel is moved in the X-axis direction) in step S91. Proceed to step S73 of FIG. When “j ≠ 3”, the process proceeds to step S85, and it is determined whether or not the image movement count number j is “4”. In the case of “j = 4”, the image to be discriminated is moved one pixel to the right (moved to the position P5 in FIG. 14E, that is, “+1” pixel is moved in the X-axis direction) in step S92, and then FIG. The process proceeds to step S73. If “j ≠ 4”, the process proceeds to step S86, and it is determined whether or not the image movement count number j is “5”. In the case of “j = 5”, the image to be discriminated is moved one pixel to the lower right (moved to the position P6 in FIG. 14F), that is, “+1” in the X-axis direction and “−1” in the Y-axis direction. Then, the process proceeds to step S73 in FIG. If “j ≠ 5”, the process proceeds to step S87, where it is determined whether the image movement count number j is “6”. In the case of “j = 6”, the image to be discriminated is moved down by one pixel in step S94 (moved to position P7 in FIG. 14G, that is, moved by “−1” pixel in the Y-axis direction). Proceed to step S73 of FIG. In the case of “j ≠ 6”, the process proceeds to step S95, where the image to be discriminated is moved by one pixel to the lower left (moved to position P8 in FIG. 14H, that is, each “−1” pixel in the X-axis direction and Y-axis direction. The process proceeds to step S73 in FIG. In FIG. 14, in order to clearly show the direction of parallel movement, the movement distance is shown large for convenience.

  In step S73 of FIG. 12, “1” is added to the current image movement count number j, and “j + 1” is set as the new image movement count number j. In other words, the image movement count number j is updated. In a succeeding step S74, it is determined whether or not the image movement count number j is “8” or more. When the image movement count number j is not “8” or more (that is, when “j <8”), the process returns to step S69, and steps S69 to S74 are repeatedly executed. As a result, the image to be discriminated is translated while changing the direction of translation, and each time the reference image and the image to be discriminated are compared with each other, the similarity SM is calculated. In other words, the reference image and the discriminated image are compared while correcting the relative positional deviation between the reference image and the discriminating image.

  In step S75 executed when the image movement count number j is “8” or more in step S74 (that is, when “j ≧ 8”), “1” is added to the current rotation angle count number i, “I + 1” is set as the new rotation angle count number i. In other words, the rotation angle count number i is updated. In a succeeding step S76, it is determined whether or not the rotation angle count number i is “2” or less. When the rotation angle count number i is “2” or less (that is, when “i ≦ 2”), the process returns to step S63, and steps S63 to S76 are repeatedly executed. As a result, the discriminated image from which the maximum similarity SMm is obtained and the two discriminated images rotated by the rotation angle fine adjustment amount θs are translated while changing the moving direction. Then, each time the reference image and the discriminated image are compared, the similarity SM is calculated. In other words, the reference image and the image to be discriminated are compared while correcting the relative rotational deviation and positional deviation of the reference image and the image to be discriminated, and the reference image and the image to be discriminated when the similarity SM is equal to or greater than a predetermined threshold value. It is determined that the discriminated images match.

  In step S76, when the rotation angle count number i exceeds “2” (that is, when “i> 2”), the process proceeds to step S77, where the reference image and the determination target image do not match (that is, the reference image and the determination target image). The discriminating images are inconsistent), and the process proceeds to step S14 in FIG. In step S14 of FIG. 7, the determination result of the determination target disk TD is output. That is, the control unit 104 outputs the determination result in the comparison determination unit 158 of the image processing unit 124 to the input / output interface 110.

  As described above, the disc discriminating apparatus 100 detects the contour De based on the captured images of the reference disc SD and the disc to be discriminated TD in the preprocessing of FIG. 10, and the center of the reference image and the discriminated image from the detected contour De. Calculate the position. Then, the reference image and the discriminated image are rotated around the center position. Therefore, it is necessary to reliably detect the contour De.

  In the disc image acquisition device 1 of the present embodiment, one surface Ds1 of the disc D is supported by the support surface 48a of the transparent plate (transparent portion) 48, and the background portion 50 is disposed on the other surface Ds2 side of the disc D. . The background portion 50 has a surface 50 a that faces the support surface 48 a of the transparent plate 48, and the surface 50 a forms a background region BR outside the contour De of the disk D. The illumination unit 10 applies illumination light including at least a red component (first color component) and a blue component (second color component) having a wavelength different from that of the red component to the surface Ds1 of the disk D and the transparent plate 48 on the background unit 50. Irradiate through. Reflected light from the surface Ds1 and the background portion 50 of the disk D passes through the transparent plate 48 and is received by the image sensor 24. The background unit 50 is configured to reflect red component illumination light and absorb blue component illumination light. The imaging device 24 receives reflected light from the surface Ds1 and the background region BR of the disk D when the disk D is on the support surface 48a of the transparent plate 48, and receives an R image (first image) corresponding to the reflected light of the red component. 1 captured image) and a B image (second captured image) corresponding to the reflected light of the red component.

  When the reflectance of the surface Ds1 of the disk D is significantly reduced, the red component illumination light is absorbed by the surface Ds1 of the disk D and reflected by the background region BR. Thereby, the reflected light of the red component becomes minute on the surface Ds1 of the disk D and remains constant in the background area BR. Therefore, in the R image, there is a pixel area RC2 having a very low luminance corresponding to the surface Ds1 of the disk D and a pixel area RB2 having a high luminance corresponding to the background area BR. Therefore, even if the disk D has a low reflectivity, the contour De of the disk D can be reliably detected by using the R image. On the other hand, when the reflectance of the surface Ds1 of the disc D is high, the blue component illumination light is reflected by the surface Ds1 of the disc D and absorbed by the background region BR. Thereby, the reflected light of the blue component is large on the surface Ds1 of the disk D and becomes minute in the background region BR. Therefore, in the B image, there is a high luminance pixel area BC1 corresponding to the surface Ds1 of the disk D and a minute luminance pixel area BB1 corresponding to the background area BR. Therefore, even in the case of the disk D having a high reflectivity, the contour De of the disk D can be reliably detected by using the B image.

  The background portion 50 includes a mirror 54 covered with a colored transparent member 56 colored in the same color as the red component. Therefore, the reflection of the illumination light in the background region BR is specular reflection, and the contrast ratio between the high-brightness pixel region RB2 and the minute-brightness pixel region RC2 is further increased. Therefore, the detection of the contour De in the R image is further ensured.

  As described above, the disc discriminating apparatus 100 detects the contour De of the disc D based on the captured image, and calculates a coordinate value indicating the center CP of the disc D from the detected contour De. Then, the image to be determined is rotated with reference to the center CP. For this reason, the calculation accuracy of the center CP affects the determination accuracy. By using the disc image acquisition device 1 of the present embodiment, the contour of the disc D can be reliably detected, so that the discrimination accuracy of the disc discrimination device 1 is improved.

  On the other hand, the imaging element 24 receives reflected light from the background portion 50 when the disk D is not present on the support surface 48a of the transparent plate 48, and receives an R image (third captured image) corresponding to the reflected light of the red component. To get. In this case, the R image is a pixel area with high brightness over the entire image. Therefore, it is possible to easily detect the dirt region DR in which the luminance is lowered due to the dirt on the transparent plate 48.

  As described above, in the disc discriminating apparatus 1, when the dirt region DR is detected, a dirt detection signal is output from the control unit 104, and the status indicator 112 notifies the dirt of the transparent plate 48. Therefore, the convenience of maintenance work in the disk discriminating apparatus 100 is improved.

  In the present embodiment, the mirror 54 is disposed in the background portion 50, but the same effect can be obtained by coloring the surface of the background portion 50 in red. Further, if the spectral sensitivity of the red pixel in the image sensor 24 reaches the approximate color of red and the spectral sensitivity in the approximate color is in a desired range, the colored transparent member 56 in the background portion 50 is replaced with the approximate color of red. It is good. The approximate red color here is orange (wavelength of 590 nm to 610 nm).

(Second Embodiment)
FIG. 15 shows a disc image acquisition device 1A according to the second embodiment of the present invention. The disc image device 1A includes a light emitting element 12a that emits illumination light of a red component and a light emitting element 12b that emits illumination light of a blue component, and the imaging unit 20 includes a monochrome imaging element 24A. This is different from the disc image acquisition device 1 of the first embodiment. Therefore, in FIG. 15, the same components as those in the disk image acquisition device 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the disc image acquisition device 1A, the illumination unit 10A is a surface illumination unit 11A that selectively irradiates red component illumination light and blue component illumination light. The surface illumination unit 11A includes a light emitting element 12a disposed at one end (left side in FIG. 15) of the light guide plate 14 and a light emitting element 12b disposed at the other end (right side in FIG. 15) of the light guide plate 14. And comprising. A red LED is used for the light emitting element 12a, and a blue LED is used for the light emitting element 12b. The illumination light of the red component is emitted from the surface illumination unit 11A by the light emission of the light emitting element 12a, and the illumination light of the blue component is emitted from the surface illumination unit 11A by the emission of the light emitting element 12b. The irradiation light of the red component and the blue component is irradiated onto the surface Ds1 of the disk D with a predetermined time difference. In addition, when the reflective dot (not shown) is formed in one surface of the reflective sheet 16 side of the light-guide plate 14, the reflective dot of the light-guide plate 14 is roughly formed in each of the light emitting elements 12a and 12b. It is preferable to arrange at the end on the side. Thereby, the illumination light of the red component and the blue component irradiated from the light guide plate 14 becomes uniform.

  The imaging unit 20 includes a monochrome imaging element 24A that acquires a single color image. The image sensor 24A receives reflected light from the half mirror 32 when the red illumination light is irradiated from the surface illumination unit 11A, outputs a captured image, and the blue illumination light is emitted from the surface illumination unit 11A. When the reflected light from the half mirror 32 is received, a captured image is output. In other words, the image sensor 24A acquires a first captured image corresponding to the red component illumination light and a second captured image corresponding to the blue component illumination light, respectively.

  The background unit 50 has the same configuration as the disc image acquisition device 1 of the first embodiment. Therefore, the first captured image is an image shown in FIG. 2A, and the second captured image is an image shown in FIG. Therefore, by detecting the contour for each of the first captured image and the second captured image, it is possible to reliably detect the contour De in both the high reflectivity disk Drh and the low reflectivity disk Drl. Even in the case of the disc D having a reflectivity between the high reflectivity disc Drh and the low reflectivity disc Drl, the contrast ratio is slightly increased by detecting the contour of each of the first captured image and the second captured image. Since there is no problem in detecting the contour of the drop, the contour De can be reliably detected.

  When the disk D is not present on the support surface 48 of the transparent plate 48, red component illumination light is emitted from the surface illumination unit 11 </ b> A toward the surface 50 a of the background unit 50. The image sensor 24A receives reflected light from the surface 50a of the background portion 50 and acquires an R image. In this case, the R image is a pixel area with high brightness over the entire image. Therefore, it is possible to easily detect a region where the brightness is lowered due to the dirt on the transparent plate 48.

  The disc image acquisition device 1A of this embodiment can be applied to the disc discrimination device 100 of FIG. In that case, the control unit 104 in FIG. 3 outputs the lighting control signal LCS corresponding to each of the light emitting elements 12a and 12b to the illumination unit 10A with a predetermined time difference, and the imaging corresponding to each of the lighting control signals LCS. The control signal ICS is output to the imaging unit 20. Accordingly, steps S7 and S8 in FIG. 7, ST1 and ST2 in FIG. 8, and steps S24 and S25 in FIG. 9 are each executed twice. The other operations of the disc determination device 100 can be implemented by appropriately changing the operation of the first embodiment, and thus detailed description thereof is omitted here.

(Third embodiment)
FIG. 16 shows a disc image acquisition device 1B according to a third embodiment of the present invention. The disc image acquisition device 1B includes a red surface illumination unit 11a that the illumination unit 10B emits red component illumination light, a blue surface illumination unit 11b that emits blue component illumination light, and a cross prism 13. In that respect, the imaging unit 20 is configured by a monochrome imaging device 24A, which is different from the disk image acquisition device 1 of the first embodiment. Therefore, in FIG. 16, the same components as those of the disk image acquisition device 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The disc image acquisition device 1B includes an illumination unit 10B that irradiates the surface Ds1 of the disc D moving on the disc transport path 40 with red component illumination light and with blue component illumination light. The The illumination unit 10B includes a red surface illumination unit 11a that emits red component illumination light, a blue surface illumination unit 11b that emits blue component illumination light, and illumination light and blue surface illumination introduced from the red surface illumination unit 11a. And a cross prism 13 that refracts each of the illumination lights introduced from the unit 11b toward the imaging window 44.

  The red surface illumination unit 11a includes a light emitting element 12a, a light guide plate 14a, a reflection sheet 16a, and a diffusion sheet 18a. A red LED is used for the light emitting element 12a, and the light emitting element 12a irradiates the light guide plate 14a with red visible light. The light guide plate 14 a has a rectangular thin plate shape extending in the vertical direction in FIG. 16 and irradiates the cross prism 13 with red component illumination light. The reflection sheet 16a is in close contact with the surface of the light guide plate 14a that is located on the opposite side of the cross prism 13, and prevents light from diffusing from the light guide plate 14a to the opposite side of the cross prism 13 to the cross prism 13 side. reflect. The diffusion sheet 18a is in close contact with the cross prism 13 side surface of the light guide plate 14a, and uniformly diffuses light irradiated from the cross prism 13 side surface of the light guide plate 14a. Irradiation light from the light emitting element 12a guided by the light guide plate 14a or reflected by the reflection sheet 16a is made a uniform amount of light over the entire surface by the diffusion sheet 18a and irradiated toward the cross prism 13.

  The blue surface illumination unit 11b includes a light emitting element 12b, a light guide plate 14b, a reflection sheet 16b, and a diffusion sheet 18b. A blue LED is used for the light emitting element 12b, and the light emitting element 12a irradiates the light guide plate 14b with blue visible light. The light guide plate 14 b has a rectangular thin plate shape extending in the vertical direction in FIG. 16, and irradiates the cross prism 13 with blue component illumination light. The reflection sheet 16b is in close contact with the surface of the light guide plate 14b that is located on the opposite side of the cross prism 13, and prevents light from diffusing from the light guide plate 14b to the opposite side of the cross prism 13. reflect. The diffusion sheet 18b is in close contact with the surface of the light guide plate 14b on the cross prism 13 side, and uniformly diffuses light irradiated from the surface of the light guide plate 14b on the cross prism 13 side. Irradiation light from the light emitting element 12a guided by the light guide plate 14b or reflected by the reflection sheet 16b is made a uniform amount of light over the entire surface by the diffusion sheet 18b and irradiated toward the cross prism 13.

  The cross prism 13 is formed by joining four prisms in the shape of a right isosceles triangle having an apex angle of 90 degrees as an edge. The cross prism 13 is located between the red surface illumination unit 11a and the blue surface illumination unit 11b, and refracts the light directed from the red surface illumination unit 11a and the blue surface illumination unit 11b in the horizontal direction in FIG. 16 by 90 degrees. Irradiate vertically upward in FIG. As a result, the red component and the blue component irradiated from the red surface illumination unit 11 a and the blue surface illumination unit 11 b are selectively irradiated onto the surface Ds 1 of the disk D through the imaging window 44. Irradiation light of these red component and blue component is irradiated with a predetermined time difference.

  The imaging unit 20 includes a monochrome imaging element 24A that acquires a single color image, like the disc image acquisition device 1A of the second embodiment. The image sensor 24A receives reflected light from the half mirror 32 when the red component illumination light is irradiated from the red surface illumination unit 11a, outputs a captured image, and emits blue component illumination light from the blue surface illumination unit 11b. The reflected light from the half mirror 32 when the light is irradiated is received and a captured image is output. In other words, the image sensor 24A acquires a first captured image corresponding to the red component illumination light and a second captured image corresponding to the blue component illumination light, respectively.

  The background unit 50 has the same configuration as the disc image acquisition device 1 of the first embodiment. Therefore, the first captured image is an image shown in FIG. 2A, and the second captured image is an image shown in FIG. Therefore, by detecting the contour for each of the first captured image and the second captured image, it is possible to reliably detect the contour De in both the high reflectivity disk Drh and the low reflectivity disk Drl. Even in the case of the disc D having a reflectivity between the high reflectivity disc Drh and the low reflectivity disc Drl, the contrast ratio is slightly increased by detecting the contour of each of the first captured image and the second captured image. Since there is no problem in detecting the contour of the drop, the contour De can be reliably detected.

  When the disk D is not present on the support surface 48 a of the transparent plate 48, red component illumination light is emitted from the red surface illumination unit 11 a toward the surface 50 a of the background unit 50. The image sensor 24A receives the reflected light from the surface 50a of the background part 50 and acquires a third captured image corresponding to the red component. In this case, the third captured image becomes a high-luminance pixel region over the entire image. Therefore, it is possible to easily detect a region where the brightness is lowered due to the dirt on the transparent plate 48.

  The disc image acquisition device 1B of this embodiment can be applied to the disc discrimination device 100 of FIG. In that case, the control unit 104 in FIG. 3 outputs the lighting control signal LCS corresponding to each of the light emitting elements 12a and 12b to the illumination unit 10A with a predetermined time difference, and the imaging corresponding to each of the lighting control signals LCS. The control signal ICS is output to the imaging unit 20. Accordingly, steps S7 and S8 in FIG. 7, ST1 and ST2 in FIG. 8, and steps S24 and S25 in FIG. 9 are each executed twice. The other operations of the disc determination device 100 can be implemented by appropriately changing the operation of the first embodiment, and thus detailed description thereof is omitted here.

(Modification)
The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the first to third embodiments, the surface illuminations 11, 11A, 11a, and 11b are used, but it is of course possible to use an illumination unit other than the surface illumination. For example, if the tilt angle is within a range that provides bright field illumination, the present invention can also be applied to a case where illumination light is irradiated obliquely. Further, the present invention can be applied to a configuration in which the imaging element 24 can directly receive the reflected light from the disk D and the background region BR without using the beam splitter 30 such as the half mirror 32.

  In the second and third embodiments, a red LED is used as the light emitting element 12a, and a blue LED is used as the light emitting element 12b, so that the red component illumination light and the blue component illumination light are emitted from the illumination units 10A and 10B. Although the surface Ds1 of the disk D is selectively irradiated, it can be realized by other configurations. For example, a color selection shutter may be provided in the illumination unit that emits white light.

1, 1A, 1B Disc image acquisition device 10, 10A, 10B Illumination unit 11, 11A Surface illumination unit 11a Red surface illumination unit 11b Blue surface illumination unit 12, 12a, 12b Light emitting element 13 Cross prisms 14, 14a, 14b Light guide plate 16 , 16a, 16b Reflective sheets 18, 18a, 18b Diffusion sheet 20 Imaging unit 22 Condensing lenses 24, 24A Imaging element 30 Beam splitter 32 Half mirror 40 Disk transport path 42 Base plate 44 Imaging window 46 Imaging region 48 Transparent plate 48a Support surface DESCRIPTION OF SYMBOLS 50 Background part 52 Base body 54 Mirror 56 Colored transparent member 100 Disc discrimination | determination apparatus 102 Imaging timing sensor 104 Control part 106 EEPROM
108 RAM
110 I / O interface 112 Status indicator 114 Mode change switch 122 Microcomputer 124 Image processing unit 132 Reference image holding unit 134 Captured image holding unit 136 Processed image holding unit 142 Edge enhancement unit 144 Contour detection unit 146 Center calculation unit 148 Effective area setting Unit 150 mask processing unit 152 size conversion unit 154 image rotation unit 156 image movement unit 158 contrast determination unit 160 stain detection unit

Claims (11)

A transparent portion having a support surface for supporting one surface of the disk;
The disk is disposed on the other surface side of the disk supported by the support surface, and has a surface facing the support surface. When the disk is present on the support surface, the surface is the contour of the disk. A background part that forms a background area outside, and
An illuminating unit that irradiates illumination light to the disk supported by the support surface and the background unit through the transparent unit;
An image sensor that receives the reflected light from one surface of the disk and the background part, which is transmitted through the transparent part, and
The illumination unit irradiates the illumination light including at least a first color component and a second color component having a wavelength different from that of the first color component;
The background portion is configured to reflect the illumination light of the first color component and absorb the illumination light of the second color component;
The image sensor receives reflected light from one surface of the disk and the background area when the disk is on the support surface, and the first captured image corresponding to the reflected light of the first color component and the A second captured image corresponding to the reflected light of the second color component, and the reflected light of the first color component is received by receiving the reflected light from the background when the disk is not on the support surface. A disk image acquisition device for acquiring a third captured image corresponding to.   The disc image acquisition device according to claim 1, wherein at least the surface of the background portion is colored in the same color or an approximate color as the first color component.   The disk image acquisition apparatus according to claim 1, wherein the background portion is configured such that reflection of the first color component in the background region is specular reflection.   The disk image acquisition apparatus according to claim 3, wherein the background portion includes a mirror covered with a transparent member colored in the same color as the first color component or an approximate color.   The disk image acquisition device according to claim 1, wherein the first color component is red and the second color component is blue. A transparent portion having a support surface for supporting one surface of the disk;
The disk is disposed on the other surface side of the disk supported by the support surface, and has a surface facing the support surface. When the disk is present on the support surface, the surface is the contour of the disk. A background part that forms a background area outside, and
An illuminating unit that irradiates illumination light to the disk supported by the support surface and the background unit through the transparent unit;
An image sensor that receives the reflected light from one surface of the disk and the background part, which is transmitted through the transparent part, and
The illumination unit irradiates the first illumination light of the first color component and the second illumination light of the second color component having a wavelength different from that of the first color component,
The background portion is configured to reflect the first illumination light of the first color component and absorb the second illumination light of the second color component;
The image sensor receives reflected light from one surface of the disk and the background area when the disk is on the support surface, and the first captured image corresponding to the reflected light of the first color component and the A second captured image corresponding to the reflected light of the second color component, and the reflected light of the first color component is received by receiving the reflected light from the background when the disk is not on the support surface. A disk image acquisition device for acquiring a third captured image corresponding to.   The disc image acquisition device according to claim 6, wherein at least the surface of the background portion is colored in the same color or an approximate color as the first color component.   The disk image acquisition device according to claim 6, wherein the background portion is configured such that reflection of the first color component in the background region is specular reflection.   The disk image acquisition device according to claim 8, wherein the background portion includes a mirror covered with a transparent portion colored in the same color as the first color component or an approximate color.   The disk image acquisition device according to any one of claims 6 to 9, wherein the first color component is red and the second color component is blue. A disc image acquisition device that captures an image of one surface of the disc to acquire a captured image, and a discriminating image generated based on the captured image acquired by the disc image acquisition device and a predetermined reference image are compared with each other. A disc discriminating device comprising: a discriminating unit for discriminating authenticity;
The disk image acquisition device comprises the disk image acquisition device according to any one of claims 1 to 10,
A contour detection unit for detecting a contour of the disc for each of the first and second captured images acquired by the disc image acquisition device;
A dirt detection unit for detecting dirt adhered to the transparent part based on the third captured image acquired by the disk image acquisition device;
A disk discrimination device further comprising: