JP6627057B1 - Copy detection device, copy detection method, and program - Google Patents

Abstract

Improve the accuracy of duplicate detection. The duplication detection device (2) removes the surface reflection light of the printed matter (1) from the image light of the printed matter (1) on which the yellow gradation is printed, captures the image, and generates a captured image represented in the RGB color gamut. I do. The copy detection device (2) converts a captured image represented by the RGB color gamut into a captured image represented by the Lab color system, and extracts a b channel representing the b value of each pixel from the captured image. The duplication detection device (2) binarizes the b value of each pixel of the b channel to generate a binarized image. Then, when the portion corresponding to the yellow gradation in the binarized image does not have a predetermined shape, the copy detection device (2) determines the print (1) as a copy.

Description

  The present invention relates to a copy detection device, a copy detection method, and a program, and more particularly, to a copy detection device, a copy detection method, and a program that can improve the accuracy of copy detection.

  QR (Quick Response) code (registered trademark), which is a kind of two-dimensional code, embeds machine-readable information in printed matter, and has a monetary value recently, as represented by air tickets and tickets. The use of QR Code (registered trademark) is expanding (for example, see Patent Documents 1 and 2). For this reason, development of a method for detecting forgery or duplication of a two-dimensional code represented by a QR code (registered trademark) is an urgent issue.

  In order to solve the above-described problems, the inventor of the present application extracts an imaging unit that captures a printed matter on which a predetermined pattern is printed to generate a captured image, and extracts a chromaticity channel representing the chromaticity of each pixel from the captured image. However, the present invention has invented a duplicate detection device including a control unit for determining a printed material as a duplicate when a portion corresponding to a predetermined pattern in the chromaticity channel does not satisfy the first condition (PCT / JP2017 / 046489). .

  In this specification, Patent Documents 1 and 2, and the specification, claims and drawings of PCT / JP2017 / 046489 are incorporated by reference.

JP 2006-318328 A WO2010 / 140639

  However, also in the invention according to PCT / JP2017 / 046489, a part of a predetermined pattern in a photographed image is whitened due to surface reflection light of a printed matter generated by external light, and the copy detection device uses the printed matter as an original. In spite of the fact, there is a risk that it is erroneously determined to be a duplicate.

  SUMMARY An advantage of some aspects of the invention is to provide a copy detection device, a copy detection method, and a program that can improve the accuracy of copy detection.

  In order to achieve the above object, a copy detecting device (2) according to a first aspect of the present invention includes a light source (105) for irradiating a printed matter (1) on which a predetermined pattern is printed with illumination light, and a light source (105). An illumination polarizer (225) disposed on an optical path from the light source (105) to the printed matter (1) to linearly polarize the illumination light from the light source (105); and light of image light of the printed matter (1). An imaging polarizer (224) arranged on a road, the polarization direction of the illumination polarizer (225) being orthogonal to that of the illumination polarizer, and removing the surface reflected light of the print (1) from the image light of the print (1). And an imaging unit (22) that captures image light of the printed matter (1) from which the surface reflected light has been removed by the imaging polarizing plate (224), and generates a non-reflection image of the printed matter (1). And extracting a chromaticity channel representing the chromaticity of each pixel from the non-reflection image, Portion corresponding to the predetermined pattern in comprises does not meet the first condition, the control unit for discriminating the printed matter (1) and replica (24), the.

  In the above-described copy detection device (2), the predetermined pattern is a gradation, and the control unit (24) is configured such that a portion corresponding to the gradation in the chromaticity channel does not have a predetermined shape. In this case, the first condition may not be satisfied, and the printed matter (1) may be determined to be a duplicate.

  In the above-described duplication detection device (2), the predetermined pattern is a gradation, and the control unit (24) is configured such that, when a portion corresponding to the gradation in the chromaticity channel is shorter than a predetermined length, The printed matter (1) may be determined to be a duplicate, assuming that the printed matter does not have the predetermined shape.

  In the copy detection device (2), the gradation is preferably a yellow gradation.

  In the above-described duplication detection device (2), the imaging unit (22) generates the captured image represented by the RGB color gamut, and the control unit (24) generates the captured image represented by the RGB color gamut. Is converted into the captured image represented by the Lab color system, a b channel representing a b value of each pixel is extracted from the captured image represented by the Lab color system, and the yellow gradation is extracted in the b channel. If the portion corresponding to the above does not have the predetermined shape, it may be determined that the first condition is not satisfied, and the printed matter (1) is determined to be a duplicate.

  In the above-described duplication detection device (2), the control unit (24) binarizes the b value of each pixel of the b channel to generate a binarized image, and the yellow gradation in the binarized image. If the portion corresponding to the above does not have the predetermined shape, it may be determined that the first condition is not satisfied, and the printed matter (1) is determined to be a duplicate.

  The above-mentioned duplication detecting device (2) further includes an illuminance sensor (25) for detecting the illuminance of the printed matter (1), and the control unit (24) responds to the illuminance detected by the illuminance sensor (25). Then, a threshold value to be compared with the b value of each pixel of the b channel may be determined, and the b value of each pixel of the b channel may be compared with the threshold value to be binarized.

  In the above-described duplication detection device (2), the control unit (24) converts the printed matter (1) into an original when a portion corresponding to the predetermined pattern satisfies the first condition and the second condition. When the first condition is satisfied and the second condition is not satisfied, it may be determined that the printed matter (1) is likely to be the duplicate. .

  In the above-described copy detection device (2), when the control unit (24) determines that the print (1) is the copy, the control unit (24) may instruct the imaging of the print (1) again. .

The duplication detection device (2) includes an imaging terminal (100) including the light source (105), the imaging unit (22), and the control unit (24), the illumination polarizer (225), and the imaging device. with use polarizing plate (224) and a cylindrical portion (220), the tubular portion and the bottom surface at can shield external light over said predetermined pattern table surface reflected light removal unit (220) (200) The illumination polarizer (225) is located on the optical path from the light source (105) to the print (1), and the imaging polarizer (224) is an image light of the print (1). It may be formed by attaching the surface reflected light removing unit (200) to the imaging terminal (100) so as to be located on the optical path of (1).

  In order to achieve the above object, a copy detection method according to a second aspect of the present invention includes a light source (105) for irradiating a printed matter (1) on which a predetermined pattern is printed with illumination light, and a light source (105). A polarizing plate (225) for linearly polarizing illumination light from the light source (105) from the light source (105) to the printed matter (1); and an optical polarizing plate (225) arranged on the optical path of image light of the printed matter (1). And an imaging polarizer (224), in which the direction of polarization of the illumination polarizer (225) is orthogonal to that of the illumination polarizer (225) and which removes surface reflected light of the print (1) from image light of the print (1); Wherein the imaging unit (22) captures image light of the printed matter (1) from which the surface reflected light has been removed by the imaging polarizing plate (224). Then, a non-reflection image of the printed matter (1) is generated, and the control unit (24) A chromaticity channel representing the chromaticity of each pixel is extracted from the reflection image, and the control unit (24) determines that the portion corresponding to the predetermined pattern in the chromaticity channel does not satisfy the first condition. The printed matter (1) is determined to be a duplicate.

  In order to achieve the above object, a program according to a third aspect of the present invention includes a light source (105) for irradiating a printed matter (1) on which a predetermined pattern is printed with illumination light, and the light source (105) An illumination polarizer (225) that is arranged on the optical path to the printed matter (1) and converts the illumination light from the light source (105) into linearly polarized light, and is arranged on the optical path of the image light of the printed matter (1); The illumination polarizing plate (225) is provided with an imaging polarizing plate (224) whose polarization directions are orthogonal to each other and which removes surface reflected light of the printed matter (1) from image light of the printed matter (1). The computer of the copy detection device (22) captures the image light of the printed matter (1) from which the surface reflected light has been removed by the imaging polarizing plate (224), and generates a non-reflection image of the printed matter (1). And extracts a chromaticity channel representing the chromaticity of each pixel from the non-reflection image. And, a portion corresponding to the predetermined pattern in the chromaticity channel, does not meet the first condition, to determine the printed material (1) and replica, it is intended to execute that.

  According to the present invention, it is possible to provide a copy detection device, a copy detection method, and a program that can improve the accuracy of copy detection.

FIG. 2 is a diagram illustrating a printed matter according to the embodiment. (A) is a figure which shows the yellow gradation in the original of a printed matter, (b) is a figure which shows the yellow gradation in the copy of a printed matter. FIG. 2 is an upper side view illustrating the entire configuration of the copy detection device according to the embodiment. It is a rear view showing the example of composition of an imaging terminal. It is an upper side sectional view showing an example of composition of a surface reflection light removal unit. FIG. 4 is a diagram for explaining a use state of the copy detection device. It is a block diagram showing an example of composition of a copy detection device concerning this embodiment. FIG. 3 is an explanatory diagram illustrating a color space of a Lab color system. (A) is a figure which shows the binarized image at the time of imaging the original of a printed matter, (b) is a figure which shows the binarized image at the time of imaging the copy of the printed matter. 9 is a flowchart illustrating details of a copy detection process. (A) is a table showing an optimal threshold for each illuminance in the copy detection device according to the present embodiment, and (b) is a table showing an optimal threshold for each illuminance in the copy detection device according to the modification. . It is a block diagram which shows the example of a structure of the copy detection apparatus concerning a modification.

  Hereinafter, the best mode for carrying out the present invention will be described.

  First, a printed matter according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a printed matter according to the present embodiment.

  As shown in FIG. 1, printed matter 1 is a two-dimensional code 11 with a logo in which a two-dimensional code such as a QR code (registered trademark) is superimposed on a visible logo image on a printing medium such as a white printing paper, It is formed by printing a substantially square frame-shaped yellow gradation 12 surrounding the outer periphery of the two-dimensional code 11 with a logo. Here, the gradation 12 is yellow because yellow is the most susceptible to reproduction among various colors. For this reason, a yellow gradation 12 is printed on the printed material 1 in order to detect whether it is an original or a duplicate.

  The logo-added two-dimensional code 11 is a general-purpose two-dimensional code for a portion of the logo image that is recognized as black by a general-purpose two-dimensional code reader and has a brightness lower than the first brightness (a background portion, a keyhole portion, and the like in the example shown in FIG. 1). Only cells of the first type of brightness that are recognized as white by the two-dimensional code reader (white cells in the example shown in FIG. 1) are overlaid. On the other hand, in a portion of the logo image having the first brightness or higher (a key body portion or the like in the example shown in FIG. 1), cells of the first type of brightness (white cells in the example shown in FIG. 1) and general-purpose cells are used. Both cells of the second type of lightness that are recognized as black by the two-dimensional code reader (black cells in the example shown in FIG. 1) are superimposed.

  The two-dimensional code 11 with a logo is recognized as a first-type lightness cell (white cell in the example shown in FIG. 1) recognized as white by a general-purpose two-dimensional code reader and as black by a general-purpose two-dimensional code reader. Distribution of a second type of brightness cell (black cell in the example shown in FIG. 1) and a portion of the logo image having less than the first brightness (background portion, keyhole portion, etc. in the example shown in FIG. 1). The pattern expresses predetermined information such as a URL (Uniform Resource Locator).

  The gradation 12 is obtained by using only the Y (yellow) ink of the four colors of the CMYK color gamut on a printing medium such as a printing paper on a white background, and forming each vertex of a substantially square having a side length of about 23 mm. From the center to the center of each side.

  FIG. 2A is a view showing a yellow gradation in an original of a printed matter. FIG. 2B is a diagram showing a yellow gradation in a copy of a printed matter.

  The inventor obtained the length of the yellow gradation 12 in the original and the copy of the printed matter 1 respectively. Here, the length of the gradation 12 refers to the length of a portion of each side of the gradation 12 where the attachment of Y (yellow) ink can be visually confirmed. The length of the yellow gradation 12 in the original was approximately 21.5 mm to approximately 23 mm as shown in FIG. On the other hand, the length of the yellow gradation 12 in the copy was shorter than the original, and was about 14 mm to about 19.5 mm, as shown in FIG.

  Thus, the yellow gradation 12 is attenuated by duplication, and the length of the yellow gradation 12 in the duplicate is shorter than the original. The reason is that the color gamut (color space), the reproduction method, and the like are different between the CMYK color gamut used for printing and the RGB color gamut used for copying. Specifically, the CMYK color gamut becomes white when the color is reduced (it becomes black when added), and the color is expressed by subtractive color mixture. The RGB color gamut becomes white as the color is added (it becomes black when the color is added). The color is expressed by additive color mixing.

  The yellow gradation 12 is converted into a mixed color of the RGB color gamut at the time of scanning, and the CMYK color gamut is used again at the time of printing. At this time, the gradation 12 is printed in a mixed color of the CMYK color gamut, and a portion having a low density (light) is further lightened. The reason lies in the mechanism for expressing colors in printing. That is, in printing, a color is expressed by whether a dot (point) of ink is put on a printing medium such as paper or not, that is, a binary value of dot on / off, and the dot shape (for example, the size of the dot) and the dot Shading of colors is expressed in a dispersed manner. Lighter colors naturally have smaller dot shapes. In order for the image sensor to acquire such small dots when scanning, sufficient resolution is required, but the resolution of a general-purpose copying machine is high. There is only about 400 ppi. Therefore, light colors tend to be easily lost, and as a result, light colors tend to be lighter. In particular, the light color of the yellow gradation 12 is more likely to change to a lighter color by duplication using a scanner or a camera.

  Next, a copy detection device according to the present embodiment for detecting whether the printed matter 1 is an original or a copy using the property of the yellow gradation 12 will be described with reference to the drawings.

  When the copy detection device according to the present embodiment captures an image of the printed matter 1 using polarized light as illumination light, the state of polarization of light reflected on the surface of the printed matter 1 (surface reflected light) is maintained as it is, and A non-reflective image of the printed matter 1 from which the surface reflected light has been removed is generated by utilizing the property of polarized light that the light reflected after entering a part of the light (internal reflected light) is in a state where the polarized light is broken. Then, the copy detection device detects whether the print 1 is an original or a copy from the non-reflection image of the print 1 using the property of the yellow gradation 12 described above.

  The details of the technique for generating a non-reflection image are described in JP-A-8-251457, JP-A-11-332830, JP-A-2005-122203, JP-A-2007-179081, and JP-A-2014. No. 018439 and the like. The specifications and claims of JP-A-8-251457, JP-A-11-332830, JP-A-2005-122203, JP-A-2007-179081, and JP-A-2014-018439. , The entire drawing shall be taken in for reference.

  FIG. 3 is an upper side view illustrating the entire configuration of the copy detection device according to the present embodiment.

  As shown in FIG. 3, the copy detection device 2 is configured by combining the imaging terminal 100 and the surface reflected light removal unit 200.

  The imaging terminal 100 includes, for example, a general-purpose smartphone or tablet computer. In the present embodiment, it is composed of iPhone (registered trademark) 6s manufactured by Apple Inc. Note that the imaging terminal 100 may be an Android (registered trademark) smartphone, a tablet computer, or the like. In addition, the imaging terminal 100 is arbitrary as long as it has an imaging function, and may be a general-purpose digital camera, a general-purpose two-dimensional code reader, or the like.

  FIG. 4 is a rear view illustrating a configuration example of the imaging terminal.

  As shown in FIG. 4, in the imaging terminal 100, a lens 104 is exposed on a surface of a housing 101. The lens 104 forms a camera of the imaging terminal 100 together with the imaging unit 22 (FIG. 7) at the back.

  The imaging terminal 100 includes a light source 105 on a surface of a housing 101 thereof. The light source 105 includes, for example, an LED (Light Emitting Diode) and irradiates the printed matter 1 with illumination light.

  The surface reflected light removal unit 200 shown in FIG. 3 is configured to be detachable from the imaging terminal 100, and from image light generated when the imaging terminal 100 images the printed material 1, reflected light from the surface of the printed material 1 (surface reflected light). ) Is removed.

  FIG. 5 is an upper cross-sectional view illustrating a configuration example of the surface reflected light removing unit.

  As shown in FIG. 5, the surface reflected light removing unit 200 includes, for example, a black resin main body 210 and a cylindrical part 220 integrally formed.

  The main body unit 210 detachably fixes the surface reflected light removal unit 200 to the imaging terminal 100. The main body 210 has a substantially circular first hole 214 and a second hole 215 at positions corresponding to the lens 104 and the light source 105 of the imaging terminal 100 when the surface reflected light removing unit 200 is fixed to the imaging terminal 100, respectively. Is provided.

  The first hole 214 is for preventing the lens 104 from being covered with the main body 210 in order to form a path for the image light of the printing unit 1, and has a circular shape having substantially the same radius as the lens 104 or a slightly larger diameter. Be composed. The first hole 214 is not limited to a circle as long as it does not cover the lens 104 with the main body 210, and may be a substantially elliptical shape or a substantially polygonal shape. It does not matter. The first hole 214 is provided with an imaging polarizer 224 that transmits image light of the printing unit 1 and converts the image light into linearly polarized light. That is, the imaging polarizing plate 224 is arranged on the optical path of the image light of the printed matter 1.

  The second hole 215 is for preventing the light source 105 from being covered with the main body 210 in order to create a path for the illumination light from the light source 105, and has a circular shape having substantially the same radius as the light source 105 or a slightly larger diameter. Be composed. The second hole 215 is not limited to a circle as long as it does not cover the light source 105 with the main body 210, and may be substantially elliptical, substantially polygonal, or the like. It does not matter. The second hole 215 is provided with an illumination polarizing plate 225 that transmits illumination light from the light source 105 and converts the illumination light into linearly polarized light. That is, the illumination polarizer 225 is arranged on the optical path from the light source 105 to the printed matter 1. The polarizing directions of the imaging polarizer 224 and the illumination polarizer 225 are orthogonal to each other.

  The cylindrical portion 220 is formed, for example, in a substantially cylindrical shape, and is attached to the main body portion 210. The cylindrical portion 220 completely covers the two-dimensional code 11 with the logo and the yellow gradation 12 on the printed matter 1 on the bottom surface when the duplicate detection device 2 images the printed matter 1, and the outer surface contributes to the surface reflected light. Block light.

As described above, the duplicate detection device 2 is configured such that the illumination polarizing plate 225 is located on the optical path from the light source 105 to the printed matter 1 and the imaging polarizing plate 224 is located on the optical path of the image light of the printed matter 1. It is formed by attaching the surface reflected light removing unit 200 having the cylindrical portion 220 capable of blocking the external light by covering the two-dimensional code 11 with the logo and the yellow gradation 12 on the bottom surface thereof to the imaging terminal 100.

  Subsequently, an operation of capturing a non-reflection image of the printed matter 1 by the copy detection device 2 having the above configuration will be described with reference to the drawings.

  FIG. 6 is a diagram for explaining the imaging operation of the copy detection device.

  As shown in FIG. 6, the illumination light from the light source 105 becomes linearly polarized light by the illumination polarizing plate 225, impinges on the printed matter 1, and reflects the image light of the printed matter 1. Of the image light of the printed matter 1, the surface reflected light that is kept linearly polarized light is removed by the imaging polarizing plate 22. On the other hand, of the image light of the printed matter 1, at least a part of the internally reflected light whose polarization has been broken passes through the polarizing plate 22 for imaging. Then, the image light having passed through the imaging polarizing plate 22 is imaged by the lens 104, and is imaged by the imaging unit 22. Thereby, the copy detection device 2 generates a non-reflection image without surface reflection light as a captured image of the printed matter 1.

  FIG. 7 is a block diagram illustrating a configuration example of the copy detection device according to the present embodiment.

  As shown in FIG. 7, the copy detection device 2 includes a light source 105, a touch panel 21, an imaging unit 22, a storage unit 23, and a control unit 24, which are connected via a bus or the like. .

  The touch panel 21 includes, for example, a general-purpose touch panel that combines a liquid crystal display device and a pointing device. The touch panel 21 displays various screens and receives various operations by the user. In the present embodiment, the touch panel 21 displays a reading icon or the like for instructing reading of the two-dimensional code 11 with a logo.

  The imaging unit 22 includes, for example, a solid-state imaging device such as a CCD (Charge Coupled Device). The imaging unit 22 captures an image of the printed matter 1 and generates a non-reflection image of the printed matter 1 represented in the RGB color gamut.

  The storage unit 23 includes, for example, a nonvolatile memory such as a general-purpose flash memory. The storage unit 23 stores a copy detection application program for detecting whether the print 1 is an original or a copy.

  The control unit 24 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls various operations of the copy detection device 2 by using the RAM as a work memory and appropriately executing programs stored in the ROM and the storage unit 23 and the like.

  In the present embodiment, the control unit 24 turns on the light source 105 in response to the user operating the touch panel 21 to activate the copy detection application program stored in the storage unit 23, and displays the read icon. It is displayed on the touch panel 21. Further, the control unit 24 fixes the brightness of the light source 105 and the gain of the amplifier inside the copy detection device 2 to fixed values. Then, the control unit 24 determines that the user completely covers the two-dimensional code 11 with the logo and the yellow gradation 12 on the printed material 1 at the bottom of the cylindrical unit 220 to block external light, and then taps the read icon. In response, the printed matter 1 is imaged by the imaging unit 22 to generate a non-reflection image of the printed matter 1 represented in the RGB color gamut. Note that, when the inclination of the non-reflection image is equal to or larger than a predetermined angle (for example, 2 °) or when the size of the non-reflection image is smaller than a predetermined size (for example, the width is 300 pixels), the control unit 24 captures the printed matter 1 May be performed again.

  The control unit 24 converts the non-reflection image of the printed matter 1 represented by the RGB color gamut generated by the imaging unit 22 into a CIE L * a * b * (hereinafter, referred to as “Lab”) color system. Convert to reflection image.

  FIG. 8 is an explanatory diagram illustrating a color space of the Lab color system.

  As shown in FIG. 8, the color space of the Lab color system is a complementary color space that expresses a color by three values such as an L value indicating lightness, and an a value and a b value indicating chromaticity (hue and saturation). is there. The L value takes a value in the range of “0” to “100”, and the larger the value, the higher the brightness. When the L value is “0”, the color becomes black, and when the L value is “100”, the color becomes white. The a value is a value indicating the chromaticity between red and green, and in the present embodiment, takes a value in a range from “−255” to “255”. When the value a is a positive value, the color becomes red, and as the positive value increases, the density of red increases. On the other hand, when the a-value is a negative value, the color becomes green, and as the negative value decreases, the density of the green color increases. The b value is a value indicating the chromaticity between yellow and blue, and in the present embodiment, takes a value in a range from “−255” to “255”. When the b value is a positive value, the color becomes yellow, and as the positive value increases, the density of yellow increases. On the other hand, when the b value is a negative value, the color becomes blue, and as the negative value decreases, the density of the blue color increases. When both the a value and the b value are “0”, the color becomes achromatic.

  The control unit 24 illustrated in FIG. 7 extracts a b channel representing the b value of each pixel of the non-reflective image from the non-reflective image represented by the color space of the Lab color system. Then, the control unit 24 compares the b value of each pixel of the b channel with a predetermined threshold (“123” in the present embodiment), and sets the b value smaller than the threshold to “0” and the b value larger than the threshold to “0”. The image is binarized so as to be 1 "to generate a binarized image.

  FIG. 9A is a diagram illustrating a binarized image when an original of a printed matter is imaged. FIG. 9B is a diagram illustrating a binarized image when a copy of a printed matter is captured.

  In the binarized images shown in FIGS. 9A and 9B, pixels set to “0” are shown in black, and pixels set to “1” are shown in white. In the binarized image obtained when the original of the printed matter is imaged, the portion corresponding to the yellow gradation 12 is almost connected as shown in FIG. 9B, only the four corners of the gradation 12 remain as shown in FIG. 9B.

  The control unit 24 illustrated in FIG. 7 detects a line segment having a predetermined length or more in a portion corresponding to the yellow gradation 12 of the binarized image. The control unit 24 determines that the printed material 1 is a duplicate when a line segment having a predetermined length or more cannot be detected in a portion corresponding to the yellow gradation 12, and, together with the determination result, displays the read icon on the touch panel 21. indicate.

  The control unit 24 detects a line segment having a predetermined length or more in any of the four sides of the portion corresponding to the yellow gradation 12, even when a line segment having a predetermined length or more can be detected in the portion corresponding to the yellow gradation 12. When the detection is not possible, it is determined that there is a possibility that the printed matter 1 is a duplicate, and the reading icon is displayed on the touch panel 21 together with the determination result.

  When the control unit 24 can detect a line segment having a predetermined length or more on any of the four sides of the portion corresponding to the yellow gradation 12, the control unit 24 determines that the print 1 is the original, and determines the determination result on the touch panel. 21. Then, the control unit 24 reads predetermined information from the logo-added two-dimensional code 11 included in the non-reflection image.

  Next, a copy detection process executed by the copy detection device having the above configuration will be described with reference to the drawings.

  The control unit 24 of the duplication detection device 2 turns on the light source 105 in response to the user operating the touch panel 21 to activate the duplication detection application program stored in the storage unit 23, and displays the read icon. It is displayed on the touch panel 21. Then, the control unit 24 determines that the user completely covers the two-dimensional code 11 with the logo and the yellow gradation 12 on the printed material 1 at the bottom of the cylindrical unit 220 to block external light, and then taps the read icon. In response, the copy detection process is started.

  FIG. 10 is a flowchart showing details of the copy detection process.

  As shown in FIG. 10, in the copy detection process, first, the control unit 24 captures an image of the printed matter 1 including the two-dimensional code 11 with a logo by the imaging unit 22 and performs non-reflection of the printed matter 1 represented in the RGB color gamut. An image is generated (Step S1).

  Next, the control unit 24 converts the non-reflection image of the printed matter 1 represented in the RGB color gamut generated in step S1 into a non-reflection image represented in the Lab color system (step S2).

  Subsequently, the control unit 24 extracts a b-channel representing the b-value of each pixel of the non-reflection image from the non-reflection image represented by the Lab color system converted in step S2 (step S3).

  Then, the control unit 24 compares the b value of each pixel of the b channel extracted in step S3 with a predetermined threshold value, and sets a b value less than the threshold value to “0” and a b value equal to or more than the threshold value to “1”. In this way to generate a binarized image (step S4).

  Subsequently, the control unit 24 detects a line segment having a predetermined length or more in a portion corresponding to the yellow gradation 12 of the binarized image generated in Step S4 (Step S5).

  When a line segment having a predetermined length or more cannot be detected in the portion corresponding to the yellow gradation 12 (step S6; No), the control unit 24 determines that the printed matter 1 is a duplicate, and together with the determination result, After the read icon is displayed on the touch panel 21 (step S7), the copy detection processing ends.

  On the other hand, even when a line segment having a predetermined length or more can be detected in the portion corresponding to the yellow gradation 12 (step S6; Yes), the control unit 24 determines that the four sides of the portion corresponding to the yellow gradation 12 are not detected. When a line segment having a predetermined length or more cannot be detected in any of the cases (Step S8; No), it is determined that there is a possibility that the printed matter 1 is a duplicate, and a reading icon is displayed on the touch panel 21 together with the determination result. After that (step S9), the copy detection process ends.

  On the other hand, when the control unit 24 can detect a line segment having a predetermined length or more on any of the four sides of the portion corresponding to the yellow gradation 12 (step S8; Yes), it determines that the printed matter 1 is the original. Then, the result of the determination is displayed on the touch panel 21 (step S10).

  Then, the control unit 24 reads predetermined information from the logo-added two-dimensional code 11 included in the non-reflection image (step S11), and ends the copy detection process.

As described above, the copy detection device 2 according to the present embodiment includes the imaging terminal 100 and the surface reflected light removal unit 200. The imaging terminal 100 includes a light source 105 that irradiates the printed matter 1 on which a predetermined pattern (yellow gradation 12) is printed with illumination light, an imaging unit 22, and a control unit 24. The surface-reflected light removing unit 200 has a cylindrical portion 220 that covers a predetermined pattern printed on the printed matter 1 and can block external light , a polarizing plate 225 for illumination, a polarizing plate 225 for illumination, and its polarization on the bottom surface. And a polarizing plate for imaging 224 whose directions are orthogonal to each other. The duplicate detection device 2 includes a surface reflection light removing unit such that the polarizing plate for illumination 225 is located on the optical path from the light source 105 to the printed matter 1 and the polarizing plate for imaging 224 is located on the optical path of the image light of the printed matter 1. It is formed by attaching 200 to the imaging terminal 100.

  The illumination polarizer 225 converts the illumination light from the light source 105 into linearly polarized light. The imaging polarizing plate 224 removes the surface reflected light of the printed matter 1 from the image light of the printed matter 1. The imaging unit 22 captures the image light of the printed matter 1 from which the surface reflected light has been removed by the imaging polarizing plate 224, and generates a non-reflection image of the printed matter 1. The control unit 24 extracts a chromaticity channel representing the chromaticity of each pixel from the non-reflection image, and copies the printed matter 1 when a portion corresponding to the predetermined pattern in the chromaticity channel does not satisfy the first condition. It is determined as a thing.

  In this embodiment, a yellow gradation is printed on the printed matter 1 as a predetermined pattern. Further, the imaging unit 22 generates a non-reflection image represented in the RGB color gamut. The control unit 24 converts the non-reflection image represented by the RGB color gamut into a non-reflection image represented by the Lab color system. Next, the control unit 24 extracts a b channel representing the b value of each pixel as a chromaticity channel from the non-reflection image represented by the Lab color system. Subsequently, the control unit 24 binarizes the b value of each pixel of the b channel to generate a binarized image.

  Then, the control unit 24 determines that the portion corresponding to the yellow gradation in the binarized image does not have a predetermined shape, that is, the portion corresponding to the yellow gradation has no line segment longer than a predetermined length. It is determined that the first condition is not satisfied, and the printed matter 1 is determined to be a duplicate.

  On the other hand, if any of the four sides of the portion corresponding to the yellow gradation has a line segment of a predetermined length or more, the control unit 24 determines that the first condition and the second condition are satisfied, and determines that the printed matter 1 is satisfied. Judge as the original. On the other hand, if there is a line segment having a predetermined length or more in a portion corresponding to the yellow gradation, but there is no line segment having a predetermined length or more in any of the four sides, the first condition is satisfied. Is satisfied but the second condition is not satisfied, it is determined that there is a possibility that the printed matter 1 is a duplicate.

  When the printed material 1 is determined to be a duplicate, the control unit 24 displays a read icon on the touch panel 21 and instructs the imaging of the printed material 1 again.

  As described above, the control unit 24 generates the non-reflection image of the printed matter 1 represented by the RGB color gamut, from which the surface reflection light causing the erroneous determination has been removed. Subsequently, the control unit 24 converts the non-reflection image represented by the RGB color gamut into a color model that has two values (a value and b value) indicating L and chromaticity and has no device dependence. Is converted into a non-reflection image represented by the Lab color system. Then, the control unit 24 extracts only the b channel that is easily affected by the duplication from the non-reflection image represented by the Lab color system, and extracts the influence of the type of the smartphone or the tablet computer that constitutes the duplication detection device 2. After removing the L channel that represents the L value that is susceptible to interference and the a channel that represents the a value that is not easily affected by duplication, the non-reflection image is binarized. This allows the control unit 24 to generate a binarized image that is hardly affected by the type of the smartphone or tablet computer that constitutes the copy detection device 2 and that has a remarkable yellow component necessary for detection of the copy. . In the binarized image generated in this manner, the amount of attenuation in the portion corresponding to the yellow gradation 12 becomes clear depending on whether the printed matter 1 is the original or a duplicate, and the control unit 24 determines that the printed matter 1 is the original. Or a copy can be easily and reliably determined. In addition, the control unit 24 can improve the accuracy of duplicate detection by determining whether the printed material 1 is an original or a duplicate using a non-reflection image from which surface reflection light that causes erroneous determination has been removed. it can.

  Note that the present invention is not limited to the above embodiment, and various modifications and applications are possible. Hereinafter, modifications of the above embodiment applicable to the present invention will be described.

  In the above embodiment, the surface reflected light removing unit 200 has been described as including the cylindrical portion 220. However, the present invention is not limited to this, and the surface reflected light removing unit 200 may not include the cylindrical portion 220. In this case, in the above embodiment, the predetermined threshold value to be compared with the b value of each pixel of the non-reflection image is described as “123”. It may be made different depending on the model, the illuminance of the printed matter 1, and the like.

  The inventor of the present invention has described a duplicate detection device 2 composed of iPhone (registered trademark) 6s made by Apple Inc. and a duplicate detection device composed of a P9 light made by Huawei according to a modification. The optimum threshold value for each illuminance in each of the device 20 (FIG. 12) was obtained. Specifically, the present inventor images the original and the duplicate of the printed matter 1 at various thresholds for each illuminance (300 lx to 1000 lx) in a general living space, and performs the duplicate detection shown in FIG. Processing was executed. Then, in the copy detection process, the printed matter 1 is correctly determined for 50 consecutive times without being determined to be a duplicate even once and without being determined to be a possibility of being duplicated twice consecutively. The determined threshold was determined as the optimal threshold.

  FIG. 11A is a table showing optimal threshold values for each illuminance in the copy detection device according to the present embodiment. FIG. 11B is a table illustrating optimal threshold values for each illuminance in the copy detection device according to the modification.

  In FIGS. 11A and 11B, “○” indicates an optimum threshold value at each illuminance. As shown in FIG. 11A, in the copy detection device 2 according to the present embodiment, “123” is included in the optimum threshold value at any illuminance. Therefore, in the present embodiment, “123” is set as the predetermined threshold value to be compared with the b value of each pixel of the non-reflection image. On the other hand, as shown in FIG. 11B, in the copy detection device 20 (FIG. 12) according to the modified example, the optimum threshold value differs depending on the illuminance of the printed matter 1.

  FIG. 12 is a block diagram illustrating a configuration example of a copy detection device according to a modification.

  As shown in FIG. 12, the copy detection device 20 includes a light source 105, a touch panel 21, an imaging unit 22, a storage unit 23, and a control unit 24 included in the copy detection device 2, and an illuminance sensor 25 that detects the illuminance of the printed matter 1. And these are connected via a bus or the like.

  The control unit 24 of the copy detection device 20 may set a predetermined threshold value to be compared with the b value of each pixel of the non-reflection image according to the illuminance detected by the illuminance sensor 25. In the example illustrated in FIG. 11B, when the illuminance detected by the illuminance sensor 25 is 300 lx to 499 lx, the control unit 24 sets the predetermined threshold to be compared with the b value of each pixel of the non-reflection image to “139”. When the illuminance is 500 lx to 699 lx, the predetermined threshold is set to “135”. When the illuminance is 700 lx to 899 lx, the predetermined threshold is set to “132”, and when the illuminance is 900 lx to 1000 lx, In some cases, the predetermined threshold may be set to “128”.

  In addition, even when the surface reflected light removing unit 200 includes the cylindrical portion 220, the predetermined threshold value to be compared with the b value of each pixel of the non-reflection image is set to a model of a smartphone or a tablet computer constituting the copy detection device 2. It may be made different depending on the situation.

  In the above-described embodiment, the control unit 24 of the copy detection device 2 determines that the printed matter 1 has a length equal to or greater than the predetermined length on any of the four sides of the portion corresponding to the yellow gradation 12. It has been described that the original is determined. However, the present invention is not limited to this, and the conditions for determining that the printed matter 1 is the original is based on the model of the smartphone or tablet computer constituting the copy detection device 2, the illuminance at the time of imaging, and the like. Can be changed as appropriate.

  For example, the control unit 24 of the copy detection device 2 detects that a line segment having a predetermined length or more can be detected on any of the four sides of the portion corresponding to the yellow gradation 12, and that a line segment having a predetermined length or more is detected. The printed material 1 may be determined to be the original on condition that the number of the printed materials 1 (for example, five or more) has been detected. Further, in addition to these conditions, the control unit 24 of the duplication detection device 2 determines the number of white pixels on the outer periphery of the two-dimensional code 11 with a logo, performs noise determination, and when the noise is 10% or more, It is determined that the printed matter 1 is a duplicate, and if the noise is 0.8% or more and less than 10%, it is determined that the printed matter 1 is possibly a duplicate, and the noise is less than 0.8%. In such a case, the printed matter 1 may be determined to be the original.

  In addition, the control unit 24 of the copy detection device 2 has been able to detect a line segment having a predetermined length or more on at least a predetermined number of sides (for example, two sides) of the four sides corresponding to the yellow gradation 12. , The printed matter 1 may be determined to be the original. Furthermore, the control unit 24 of the copy detection device 2 has been able to detect a line segment having a predetermined length or more on at least a predetermined number of sides (for example, two sides) of the four sides corresponding to the yellow gradation 12. In addition, the printed matter 1 may be determined to be the original on the condition that a line segment having a predetermined length or more has been detected for a predetermined number (for example, five lines) or more.

  In the above embodiment, the gradation 12 has been described as having a substantially square frame shape. However, the present invention is not limited to this, and the shape of the gradation 12 is arbitrary, and for example, may be linear. In this case, the control unit 24 of the copy detection device 2 obtains the length of the portion corresponding to the yellow gradation 12 in the binary image, and the length of the portion corresponding to the yellow gradation 12 is longer than the predetermined length. If it is shorter, it may be determined that the printed matter 1 does not have a predetermined shape and the printed matter 1 is determined to be a duplicate.

  In the above embodiment, the control unit 24 has been described as converting the non-reflection image represented by the RGB color gamut into a non-reflection image represented by the Lab color system. However, the present invention is not limited to this, and may be any color system that can be separated into lightness and chromaticity. For example, the control unit 24 may convert the non-reflection image represented by the RGB color gamut into a non-reflection image represented by a YUV color system, a YCbCr color system, a YPbPr color system, or the like. Good.

  Further, the control unit 24 may convert the non-reflection image represented by the RGB color gamut into a non-reflection image represented by the CMYK color gamut. The control unit 24 extracts a Y channel representing the Y (yellow) value of each pixel of the non-reflection image from the non-reflection image represented by the CMYK color gamut, and sets the Y value of each pixel of the Y channel to a predetermined threshold value. In comparison, a binarized image is generated by binarizing the Y value smaller than the threshold value to “0” and the Y value equal to or larger than the threshold value to “1”. Then, the control unit 24 detects a line segment having a predetermined length or more in a portion corresponding to the yellow gradation 12 of the binarized image, and determines whether the print 1 is an original or a duplicate. May be.

  However, when the captured image is not a non-reflective image and converted to a captured image represented in the CMYK color gamut instead of a captured image represented in the Lab color system, the quality of the light source at the time of capturing (close to white light) And whether the brightness is high, etc.), the paper quality of the printed matter 1 (whether it is coated paper or matte paper and the paper thickness, etc.), and the distance and angle between the printed matter 1 and the copy detection device 2 at the time of imaging. At the time of image pickup, subtle light and darkness or the like occurs in the printed matter 1. For this reason, unless the printed matter 1 is made of paper having stable smoothness, and the light source condition, and the distance and angle between the printed matter 1 and the copy detection device 2 at the time of imaging are stable, unless the environment is stable. At the time of binarization, it is difficult to detect only a portion corresponding to the yellow gradation 12 due to the influence of delicate light and darkness generated at the time of imaging. Therefore, in order to cut off the information relating to the extra lightness and to extract only the portion corresponding to the yellow gradation 12 composed of the yellow component, the information is expressed in the Lab color system rather than converted into a captured image expressed in the CMYK color gamut. It is preferable to convert the image into a captured image. On the other hand, in the present invention, since the captured image is a non-reflective image, not only when converted to a captured image represented by the Lab color system, but also when converted to a captured image represented by the CMYK color gamut, yellow Only the portion corresponding to the gradation 12 can be properly detected.

  Further, the control unit 24 does not need to convert the non-reflection image represented by the RGB color gamut, and the color system representing the non-reflection image is arbitrary.

  In the above embodiment, the gradation is described as being yellow, but the present invention is not limited to this. The gradation may be a color other than yellow. Even if it is a gradation of a color other than yellow, it is not as good as the gradation of yellow, but the light color is attenuated and changed to white (paper color) by duplication, and the length of the gradation becomes shorter than the original. When the gradation is red or green, the control unit 24 extracts the a channel representing the a value of each pixel of the non-reflection image from the non-reflection image represented by the Lab color system, and What is necessary is just to determine whether it is an original or a duplicate.

  In the above embodiment, the pattern printed on the printed matter 1 has been described as a gradation, but the present invention is not limited to this. The pattern printed on the printed matter 1 is arbitrary as long as its shape changes by duplication. For example, a density of 20% to 30% using only K (black) ink in the CMYK color gamut. May be a gray (one-dimensional black) pattern printed on the printed matter 1.

  Such a gray (one-dimensional black) pattern is converted into a mixed color of RGB color gamut (three-dimensional red, green, and blue) at the time of scanning, and the CMYK color gamut is used again at the time of printing. At this time, the pattern is printed in a mixed color (cyan, magenta, yellow, and black four-dimensionally) and changes to cloudy and bluish gray. In the mixed color printing, 100% pure black can be expressed in the RGB color gamut, but 100% pure black cannot be physically created only with CMY inks in the CMYK color gamut. This is because black (black) ink must be used.

  Then, the control unit 24 extracts the a-channel and / or the b-channel from the non-reflection image represented by the Lab color system, and based on the a-value and / or b-value of the portion corresponding to the pattern, It is determined whether or not a color other than black is mixed with a predetermined reference value or more. If the control unit 24 determines that a color other than black is mixed in the pattern at or above the predetermined reference value, the control unit 24 determines that the first condition is not satisfied, and determines that the print 1 is a duplicate.

  In the above embodiment, the printed matter 1 has been described as including the two-dimensional code 11 with a logo. However, the present invention is not limited to this. The printed matter 1 may include something other than the two-dimensional code 11 with a logo, such as a barcode or a document, or may contain nothing other than the gradation 12.

  In the above embodiment, the printed matter 1 has been described by way of example of the logo-attached two-dimensional code 11 in which a two-dimensional code is superimposed on a visible logo image. However, the present invention is not limited to this, and may be a general-purpose two-dimensional code expressing predetermined information by a distribution pattern of white cells and black cells.

  In the above-described embodiment, the two-dimensional code with logo 11 is such that, while only the cells of the first type of brightness are superimposed on a portion of the logo image having a brightness lower than the first brightness, the first image of the logo image is superimposed. The description has been made assuming that both the cells of the lightness of the first type and the cells of the lightness of the second type are superimposed on the portion of the brightness or higher. However, the invention is not so limited.

  For example, in the two-dimensional code 11 with a logo, only a cell of the first type of brightness is superimposed on a portion of the logo image having a brightness lower than the first brightness, and a portion of the logo image having a brightness equal to or higher than the first brightness is lower than the brightness of the second brightness. Means that a cell of the first type of brightness and a cell of the second type of brightness are superimposed on each other, and a portion of the second type or higher that is recognized as white by a general-purpose two-dimensional code reader has a second type of brightness. May be superimposed. In this case, the two-dimensional code 11 with the logo is generated by the general-purpose two-dimensional code reader using the first type of lightness cell recognized as white by the general-purpose two-dimensional code reader and the second or higher brightness part of the logo image. Predetermined information is expressed by a distribution pattern of cells of the second type of lightness recognized as black and a portion of the logo image having a value lower than the first lightness (see, for example, WO2011 / 118540).

  Further, the two-dimensional code 11 with a logo is obtained by superimposing a cell having a predetermined brightness which is recognized as white by a general-purpose two-dimensional code reader on a logo image having a predetermined brightness which is recognized as black by a general-purpose two-dimensional code reader. May be used. In this case, the two-dimensional code 11 with a logo is a cell with a predetermined brightness or higher that is recognized as white by a general-purpose two-dimensional code reader, a logo image with lower brightness than a predetermined brightness that is recognized as black by a general-purpose two-dimensional code reader, The predetermined information is expressed by the distribution pattern (see, for example, JP-A-2007-287004).

  Further, the two-dimensional code 11 with a logo has a predetermined brightness that is recognized as white by the general-purpose two-dimensional code reader in a portion of the logo image having a brightness lower than the predetermined brightness recognized by the general-purpose two-dimensional code reader as black. Are superimposed on a portion having a predetermined brightness which is recognized as white by a general-purpose two-dimensional code reader, and a cell having a predetermined brightness which is recognized as black by a general-purpose two-dimensional code reader is superimposed. (For example, see JP-A-2008-15564).

  In addition, in this specification, the specification of JP-A-2007-287004, JP-A-2008-15564, and WO2011 / 118540, the claims, and the entire drawings are incorporated by reference.

  In the above embodiment, the two-dimensional code has been described as being a QR code (registered trademark). However, the present invention is not limited to this. The two-dimensional code is, for example, another matrix type two-dimensional code such as a data matrix, an Aztec code, a code one, an array tag, a box graphic code, a maxi code, a peri code, a soft strip, a CP code, a carla code, and an ultra code. There may be. Alternatively, a stack type two-dimensional code in which one-dimensional bar codes such as PDF417, code 49, code 16k, and coder block are vertically stacked may be used.

  In the above embodiment, the program executed by the CPU of the control unit 24 has been described as being stored in advance in the ROM, the storage unit 23, and the like. However, the present invention is not limited to this. The program for executing the process may be applied to an existing general-purpose computer to function as the copy detection device 2 according to the above embodiment.

  The method of providing such a program is arbitrary. For example, the program may be stored in a computer-readable recording medium (such as a flexible disk, a CD (Compact Disc) -ROM, or a DVD (Digital Versatile Disc) -ROM) and distributed. Alternatively, the program may be stored in a storage on a network such as the Internet, and provided by downloading the program.

  Further, when the above processing is performed by sharing an OS (Operating System) and an application program, or when the OS and the application program cooperate with each other, only the application program may be stored in a recording medium or a storage. It is also possible to superimpose a program on a carrier wave and distribute it via a network. For example, the program may be posted on a bulletin board (BBS: Bulletin Board System) on a network, and the program may be distributed via the network. Then, this program may be activated and executed in the same manner as other application programs under the control of the OS, so that the above-described processing can be executed.

  Note that the present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Further, the above-described embodiment is for describing an example of the present invention, and does not limit the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Printed matter 2 Duplication detection apparatus 11 Two-dimensional code with logo 12 Gradation 20 Duplication detection apparatus 21 Touch panel 22 Imaging unit 23 Storage unit 24 Control unit 25 Illuminance sensor 100 Imaging terminal 104 Lens 105 Lighting 200 Surface reflected light removal unit 214 First hole 215 Second hole 220 Cylindrical part 224 Imaging polarizing plate 225 Illuminating polarizing plate

Claims (12)

A light source (105) for irradiating a printed matter (1) on which a predetermined pattern is printed with illumination light;
An illumination polarizing plate (225) disposed on an optical path from the light source (105) to the printed matter (1), and configured to linearly polarize illumination light from the light source (105);
The polarizing plate (225) for illumination is arranged on the optical path of the image light of the printed matter (1), and its polarization direction is orthogonal to the surface of the printed matter (1) from the image light of the printed matter (1). An imaging polarizer (224) for removing light;
An imaging unit (22) that captures image light of the printed matter (1) from which the surface reflected light has been removed by the imaging polarizing plate (224) and generates a non-reflective image of the printed matter (1);
A chromaticity channel representing the chromaticity of each pixel is extracted from the non-reflection image. If a portion corresponding to the predetermined pattern in the chromaticity channel does not satisfy the first condition, the printed matter (1) is copied. A control unit (24) for determining the object;
A copy detection device (2) comprising: The predetermined pattern is a gradation,
When the portion corresponding to the gradation in the chromaticity channel does not have a predetermined shape, the control unit (24) determines that the first condition is not satisfied and regards the printed matter (1) as a copy. Judge,
A duplication detection device (2) according to claim 1. The predetermined pattern is a gradation,
When the portion corresponding to the gradation in the chromaticity channel is shorter than a predetermined length, the control unit (24) determines that the printed matter (1) is not a duplicate and determines that the printed matter (1) is a duplicate. Do
A duplication detection device (2) according to claim 2. The gradation is a yellow gradation,
A duplication detection device (2) according to claim 2 or 3. The imaging unit (22) generates the non-reflection image represented by an RGB color gamut,
The control unit (24) converts the non-reflection image represented by the RGB color gamut into the non-reflection image represented by a Lab color system,
Extracting a b channel representing a b value of each pixel from the non-reflection image represented by the Lab color system;
If the portion corresponding to the yellow gradation in the b channel does not have the predetermined shape, it is determined that the first condition is not satisfied, and the printed matter (1) is determined as a duplicate.
A duplication detection device (2) according to claim 4. The control unit (24) binarizes the b value of each pixel of the b channel to generate a binarized image,
When the portion corresponding to the yellow gradation in the binarized image does not have the predetermined shape, it is determined that the first condition is not satisfied, and the printed matter (1) is determined to be a duplicate.
Copy detection device (2) according to claim 5. An illumination sensor (25) for detecting the illumination of the printed matter (1);
The control unit (24) determines a threshold value to be compared with the b value of each pixel of the b channel according to the illuminance detected by the illuminance sensor (25),
Binarizing the b value of each pixel of the b channel with the threshold value;
A duplication detection device (20) according to claim 6. The control unit (24) determines that the printed matter (1) is an original when a portion corresponding to the predetermined pattern satisfies the first condition and the second condition,
When the first condition is satisfied but the second condition is not satisfied, it is determined that the printed matter (1) is possibly the duplicate.
A duplication detection device (2) according to any one of the preceding claims. The control unit (24) instructs a re-imaging of the printed matter (1) when determining the printed matter (1) as the duplicate.
A duplication detection device (2) according to any one of the preceding claims. An imaging terminal (100) including the light source (105), the imaging unit (22), and the control unit (24);
The illumination polarizing plate (225), the imaging polarizing plate (224), and a cylindrical portion (220) are provided, and the bottom surface of the cylindrical portion (220) covers the predetermined pattern and can block external light. comprising a front surface reflected light removal unit (200), a
The illumination polarizer (225) is located on the optical path from the light source (105) to the printed matter (1), and the imaging polarizer (224) is located on the optical path of image light of the printed matter (1). To be formed by attaching the surface reflected light removing unit (200) to the imaging terminal (100).
A duplication detection device (2) according to any one of the preceding claims. A light source (105) for irradiating the printed matter (1) on which a predetermined pattern is printed with illuminating light; and a light source (105) arranged on an optical path from the light source (105) to the printed matter (1). An illumination polarizing plate (225) for converting light into linearly polarized light, and an illumination polarizing plate (225) disposed on the optical path of image light of the printed matter (1), wherein the polarization direction of the illumination polarizing plate (225) is orthogonal to that of the printed matter (1). A copy detection device (22) comprising: an imaging polarizing plate (224) for removing the surface reflected light of the printed matter (1) from the image light of 1);
An imaging unit (22) captures image light of the printed matter (1) from which the surface reflected light has been removed by the imaging polarizing plate (224) to generate a non-reflection image of the printed matter (1);
A control unit (24) extracts a chromaticity channel representing the chromaticity of each pixel from the non-reflection image,
The control unit (24) determines that the printed matter (1) is a duplicate if a portion corresponding to the predetermined pattern in the chromaticity channel does not satisfy a first condition.
Duplication detection method. A light source (105) for irradiating the printed matter (1) on which a predetermined pattern is printed with illuminating light; and a light source (105) arranged on an optical path from the light source (105) to the printed matter (1). An illumination polarizing plate (225) for converting light into linearly polarized light, and an illumination polarizing plate (225) disposed on the optical path of image light of the printed matter (1), wherein the polarization direction of the illumination polarizing plate (225) is orthogonal to that of the printed matter (1). A computer for a copy detection device (22), comprising:
Imaging the image light of the printed matter (1) from which the surface reflected light has been removed by the imaging polarizing plate (224) to generate a non-reflection image of the printed matter (1);
Extracting a chromaticity channel representing the chromaticity of each pixel from the non-reflective image,
If the portion corresponding to the predetermined pattern in the chromaticity channel does not satisfy the first condition, the printed matter (1) is determined to be a duplicate.
A program that lets you do things.