JP6529413B2 - Pattern generation apparatus, information embedding apparatus, information detection apparatus, method, medium, and program - Google Patents

Description

  The present invention relates to a pattern generation apparatus, an information embedding apparatus, an information detection apparatus, a method, a medium, and a program for applying information to an input medium and detecting the information.

  Pattern that can not be seen in the original copy of the copy as a technology to simply prevent forgery of valuable media (for example, concert tickets) and media for which anti-counterfeiting is important (for example, resident card or family register) There is a technology in which a ground pattern is printed in advance on the original so that characters and letters are generated. This technology utilizes the occurrence of moiré at the time of reading with a copying machine, and moiré causes a pattern (for example, characters and patterns indicating that it is a copy) to an image after being read. With this technique, since information which is not in the original copy appears in the copy, the original and the copy can be easily distinguished visually.

  However, this technique is premised on visual confirmation by a person and can not be used for the purpose of automatically determining whether the original is a copy or a copy by reading the medium. This is because, even if the original document is read, if the "reading" process is performed, a pattern similar to that of a copy is generated in the data of the reading result. That is, the data obtained by reading the original will be the same as the data obtained by reading the copy in a state in which the pattern generated by the moire can be visually confirmed.

  As one of the approaches to read the medium using a reader such as a camera and to prevent forgery by the copying machine at low cost instead of assuming visual confirmation, “The copying machine emits light from the front A method is conceivable in which information is embedded in the surface of the medium with unevenness (for example, embossing) by utilizing the fact that small unevenness on the surface of the medium is not easily reflected by the copying machine. When reading information embedded by emboss, for example, a plurality of images obtained by photographing the medium under illumination conditions in a plurality of directions (for example, two directions in the obliquely upward direction and directly above) in which unevenness can be easily detected (for example, By patent document 1), the information embedded by the unevenness | corrugation can be extracted.

Japanese Patent Application Laid-Open No. 2000-037977

  However, if information is embedded on the medium surface in the form of letters and numbers due to unevenness, there is a problem that reading of the information becomes difficult when there are scratches, breakages, or clogs in local portions where the letters or numbers are engraved. . This means that the robustness is low.

  The present invention has been made to solve the above problems, and provides a pattern generation device, an information embedding device, a method, a medium, and a program that can embed information in a medium with a concavo-convex pattern. To aim.

  Another object of the present invention is to provide an information detection apparatus, method, and program capable of detecting ID information with high accuracy from a pattern of asperities formed on a medium.

  In order to achieve the above object, a pattern generation device according to a first aspect of the invention includes a digital watermark pattern generation unit that generates a linear digital watermark pattern represented by multivalued pixel values based on embedded information; The line using the intermediate value between the maximum pixel value and the minimum pixel value of the linear digital watermark pattern as a threshold based on each pixel value of the linear digital watermark pattern generated by the digital watermark pattern generation unit And a binarization processing unit that generates a binarized linear digital watermark pattern obtained by binarizing each pixel value of the digital watermark pattern.

  According to the first aspect of the invention, the digital watermark pattern generation unit generates a linear digital watermark pattern represented by multivalued pixel values based on the embedded information, and the line generated by the binarization processing unit Each pixel value of the linear digital watermark pattern is binarized by using, as a threshold value, an intermediate value between the maximum pixel value and the minimum pixel value of the linear digital watermark pattern based on each pixel value of the digital digital watermark pattern Generate a binarized linear digital watermark pattern.

  In this manner, a linear digital watermark pattern is generated based on the embedded information, and a binarized linear digital watermark pattern is generated based on each pixel value of the generated linear digital watermark pattern. Thus, information can be embedded in the medium in a concavo-convex pattern.

  An information embedding apparatus according to a second aspect of the present invention is an embossed ID for processing a medium so as to form on a surface unevenness of a binarized linear digital watermark pattern generated by the pattern generation apparatus according to the first aspect. It is comprised including an embedding part.

  An information embedding method according to a third aspect of the present invention is the information embedding method in an information embedding device including an embossed ID embedding unit, wherein the embossed ID embedding unit is generated based on the embedded information. Using the intermediate value between the maximum pixel value and the minimum pixel value of the linear digital watermark pattern generated based on each pixel value of the linear digital watermark pattern represented by the pixel value of The medium is processed so as to form on the surface unevenness of a binarized linear digital watermark pattern obtained by binarizing each pixel value of the digital digital watermark pattern.

  According to the second and third inventions, each pixel of the linear digital watermark pattern is used by the emboss ID embedding unit using an intermediate value between the maximum pixel value and the minimum pixel value of the linear digital watermark pattern as a threshold value. The medium is processed so as to form on the surface the concavities and convexities of a binarized linear digital watermark pattern whose value has been binarized.

  In this manner, the information is formed as unevenness by processing the medium to form on the surface the unevenness of the binarized linear digital watermark pattern obtained by binarizing each pixel value of the linear digital watermark pattern. It can be embedded in the medium in a pattern.

  In the information embedding apparatus according to the second aspect of the present invention, the information embedding apparatus further includes a medium input unit for physically inputting the medium, the information to be embedded is ID information, and the emboss ID embedding unit is the medium input unit. The medium is processed to form asperities of the binarized linear digital watermark pattern with an embosser, which is a mold for embossing, on an arbitrary area of the surface of the medium input by Good.

  An information detection apparatus according to a fourth aspect of the present invention is an information detection apparatus for detecting ID information embedded in advance in a medium by photographing the medium to be targeted, and an imaging apparatus for photographing the medium A camera input unit for capturing the medium for each illumination environment using at least one illumination light source and acquiring as digital data, and based on each of the acquired images, all of the images An image pair is created for the combination, and a difference image is calculated for each of the image pair by calculating a difference value of pixel values for each image included in the image pair, and for each of the difference images, the difference image is calculated Calculating a sum of absolute values of each of the pixel values, and selecting the difference image having the largest calculated sum, and combining the selected difference images A concavo-convex degree determining unit that determines whether a shade formed by the concavo-convex has been detected based on the value and a predetermined threshold value; and when it is determined that the shade has been detected, the selected difference image And an embossed ID detection unit that detects the ID information embedded as the concavo-convex pattern.

  In the information detection method according to the fifth aspect of the present invention, a medium serving as an object is captured by including a camera input unit with auxiliary illumination, a difference image calculation unit, an unevenness degree determination unit, and an emboss ID detection unit. An information detection method in an information detection apparatus for detecting ID information embedded in the medium in advance, wherein the camera input unit with auxiliary illumination is an imaging apparatus for imaging the medium, and at least one or more of them. The medium is photographed for each illumination environment using an illumination light source and acquired as digital data, and the difference image calculation unit creates an image pair for all combinations of images based on each of the acquired images. And calculating, for each of the image pairs, a difference image by calculating a difference value of pixel values of each image included in the image pair, and for each of the difference images, The sum of the absolute values of the pixel values of the divided image is calculated, the difference image having the largest calculated sum is selected, and the unevenness degree determination unit determines the sum of the selected difference images Based on a predetermined threshold value, it is determined whether or not the shadow generated by the unevenness can be detected, and the emboss ID detection unit determines from the selected difference image when it is determined that the shadow can be detected. ID information embedded as a concavo-convex pattern is detected.

  According to the fourth and fifth inventions, the medium is photographed for each illumination environment using the photographing device for photographing the medium and the at least one illumination light source by the camera input unit with auxiliary illumination Data is acquired as data, and the difference image calculation unit creates an image pair for every combination of images based on each of the acquired images, and for each of the image pairs, the pixel value of each image included in the image pair The difference image is calculated by calculating the difference value, the sum of the absolute values of the pixel values of the difference image is calculated for each difference image, and the difference image having the largest calculated sum is selected The unevenness degree judging unit judges whether or not the shadow generated by the unevenness can be detected based on the total value of the selected difference image and a predetermined threshold value, and the emboss ID detection unit can detect the shadow Tatto If it is constant, to detect the ID information embedded as a concavo-convex pattern from the difference image selected.

  Thus, the medium is photographed for each illumination environment, acquired as digital data, an image pair is created based on each of the acquired images, a difference image is calculated for each of the image pairs, and For each, the sum of the absolute values of each of the pixel values of the difference image is calculated, the difference image with the largest calculated sum is selected, and the sum of the selected difference images and a predetermined threshold value On the basis of this, it is determined whether or not the shadow produced by the unevenness has been detected, and if it is determined that the shadow has been detected, the medium is detected by detecting ID information embedded as the unevenness pattern from the selected difference image. The ID information can be detected with high accuracy from the formed unevenness pattern.

  The medium according to the sixth aspect of the present invention is a medium in which a linear pattern is embedded with unevenness, and the linear pattern is a linear digital watermark pattern in which each pixel value is represented by a binary value. is there.

  Further, a program according to the present invention is a program for causing a computer to function as the above-described pattern generation device, an information embedding device, or each part of an information detection device.

  As described above, according to the pattern generation apparatus of the present invention, a linear digital watermark pattern is generated based on the embedded information, and 2 is generated based on each pixel value of the generated linear digital watermark pattern. Information can be embedded in the medium in a concavo-convex pattern by generating a linearized digital watermark pattern.

  Further, according to the information embedding apparatus, method, and program, the medium is configured to form on the surface the unevenness of the binarized linear digital watermark pattern obtained by binarizing each pixel value of the linear digital watermark pattern. By processing the information, information can be embedded in the medium in a concavo-convex pattern.

  Further, according to the information detection apparatus, method, and program, a medium is photographed for each illumination environment, acquired as digital data, an image pair is created based on each of the acquired images, and each of the image pairs is generated. The difference image is calculated, and for each difference image, the sum of the absolute values of the pixel values of the difference image is calculated, and the difference image having the largest calculated sum is selected, and the selected difference image Based on the total value and a predetermined threshold value, it is determined whether or not the shadow produced by the unevenness has been detected, and when it is determined that the shadow has been detected, the selected differential image is embedded as an unevenness pattern. By detecting the ID information, the ID information can be accurately detected from the concavo-convex pattern formed on the medium.

It is a figure which shows an example of the image which copied the medium which embedded embossing ID by the copying machine. It is a figure which shows an example which images the medium which gave the process of the embossing seen from a specific angle. It is a figure which shows an example which images the medium which gave the process of the embossing seen from a specific angle. It is a figure showing the composition of the information embedding system concerning a 1st embodiment of the present invention. It is a block diagram showing functional composition of a pattern generation device concerning a 1st embodiment of the present invention. It is a block diagram showing functional composition of an information detecting device concerning a 1st embodiment of the present invention. It is a figure which shows an example of a lighting environment. It is a flowchart which shows the pattern generation processing routine in the pattern generation apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the detection processing routine in the information detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the information embedding system which concerns on the 2nd Embodiment of this invention. It is a block diagram showing functional composition of a pattern generation device concerning a 2nd embodiment of the present invention. It is a block diagram showing functional composition of an information detecting device concerning a 2nd embodiment of the present invention. It is a flowchart which shows the pattern generation processing routine in the pattern generation apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the detection processing routine in the information detection apparatus which concerns on the 2nd Embodiment of this invention.

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

<Overview of Embodiments of the Present Invention>
First, an outline of an embodiment of the present invention will be described. The apparatus according to the present embodiment can apply individual ID information to a paper medium on which an arbitrary pattern, an image, etc. is printed or a medium according to the same without visually affecting the background pattern or the image. The present invention relates to an ID information embedded detection apparatus and method which can be performed and which is difficult to copy in a general copy machine or the like.

  There is a digital watermarking technology as a technology to embed information in a wide area by enhancing resistance to partial information loss. Using the digital watermarking technology, information can be embedded in a large area of the surface of the medium so as to maintain robustness, so that information can be restored even if local partial reading is difficult.

  Therefore, in the present embodiment, processing of three-dimensional unevenness (hereinafter referred to as emboss) fine for the print medium (it is difficult to read by illumination from the front by a copying machine, but shaded by oblique illumination) The watermark pattern is applied to record and embed ID information (hereinafter referred to as emboss ID), and the emboss ID is detected using a camera having a plurality of illumination light sources.

  FIG. 1 shows an example of an image when a medium created by embedding an emboss ID is copied by applying a emboss process. As shown in FIG. 1, the unevenness embedded by the emboss does not appear after copying.

  Moreover, FIG. 2 and FIG. 3 represent an example of an image view seen from different angles, showing an example of imaging a medium created by embedding an emboss ID by applying embossing processing. Here, the information embedded by embossing is not visible at the angle of FIG. 2, but the pattern is clearly visible at the angle of FIG. Therefore, in the case of authenticity judgment of the medium, the medium is embedded by reading the medium at an angle corresponding to FIG. 3 (a predetermined angle corresponding to the depth and width of the unevenness of the emboss, etc.) and illumination conditions. Information can be read.

  In addition, it is possible to create a digital watermark of a pattern composed of “linear patterns” suitable for emboss expression from information to be embedded (Non-patent document 1: Takao Nakamura, Atsushi Katayama, Masashi Yamamuro, Sonehara Noto, "High-speed digital watermark detection method from analog images using camera-equipped mobile phones," Transactions of the Institute of Electronics, Information and Communication Engineers, D-II Vol. J87-D-II, No. 12, pp. 2145-2155, 2004). In addition, when embedding information by embossing, it is a linear pattern that is suitable for embedding information, and in addition to the decrease in the amount of information that can be embedded, spatially low-frequency patterns reduce scratches and dents on flat parts. It is not suitable for embedding information in embossing because it is susceptible to the influence and the robustness is reduced.

  However, the linear pattern created by the technique of Non-Patent Document 1 described above is a pattern having multiple values, and only a binary pattern can be expressed by embossing, so the technique described in Non-Patent Document 1 is used as it is And, it does not become an embossed pattern. Therefore, in the present embodiment, as described later, a binary pattern is created, and the binary pattern is used as an embossed pattern.

  Further, in the present embodiment, an ID information embedding portion for embedding ID information and an ID information detection portion for detecting ID information are divided.

  In the ID information embedded portion, the already printed object is subjected to addition of a frame edge and processing of embossing representing a digital watermark pattern. Embossed printed matter has the property that even if it is applied to a general copying machine, the embossed shadow pattern is not copied.

  This is because, in the scanner of the copying machine, since light is uniformly emitted from the front to the printing medium surface, shading due to fine unevenness does not occur. Therefore, the watermarked print medium obtained by the present embodiment is difficult to copy, such as copying a shadow pattern by a copying machine.

  In addition, as a condition under which the embossed pattern is not reflected as a shadow pattern, it is important not to make the depth of the unevenness too deep. In the present embodiment, for example, about 0.01 mm to 0.1 mm is used as the depth of the unevenness. However, it is not limited to the said range. Also, in order to increase the number of bits of ID information, the width of the line should be as thin as possible. However, since the embossable line width is generally up to about 1 pt = 0.35 mm, it is necessary to stop at a width larger than that. Further, as a medium to be printed, it is preferable to use a solid material such as a thick paper or a plastic sheet so that the concavo-convex pattern can be stored for a long time.

  On the other hand, in the ID information detection portion, a plurality of illumination light sources are blinked in a predetermined order, and synchronized with that, a plurality of camera capture images are obtained. Then, the frame edge of the print medium is detected from the image and projective conversion is performed, and after normalization to an image viewed from the front, a difference image is calculated from a plurality of camera capture images. As a result of the calculation, when the sum of difference values is larger than the threshold value, it is determined that the input image is a print medium including fine unevenness.

  Also, digital watermark information is detected from the difference image that has been determined to be a print medium that includes fine asperities, and the result is output. This makes it possible to identify whether the detected digital watermark information is a shadow pattern generated by embossing, and whether it is a forgery with a two-dimensional density pattern printed by a general printer Can be determined.

  From the above, in the present embodiment, since the ID information is embedded by applying the embossing process to the print medium and recording the watermark pattern, even a general copying machine can not copy the watermark pattern. Also, since a camera having a plurality of illumination light sources is used to detect its ID information, only a shadow pattern by embossing can be extracted, and a two-dimensionally forged watermark pattern can be eliminated. As a result, it is possible to create a watermarked print medium that is difficult to copy.

<Configuration of Information Embedding System According to First Embodiment>
Next, the configuration of the information embedding system according to the first embodiment will be described. As shown in FIG. 4, the information embedding system 100 according to the first embodiment includes a print medium input unit 101, a frame edge providing device 102, an embossed ID embedding device 103, a print medium output unit 104, and pattern generation. An apparatus 105, a control unit 106, and a transport unit 107 are provided.

  The print medium input unit 101 physically receives a target print medium, and conveys the print medium to the frame border applying device 102 via the conveyance unit 107. In the first embodiment, the print medium is a paper medium. In the first embodiment, it is assumed that the print medium is printed with an arbitrary pattern or image. In addition to the paper medium, the print medium may be a medium conforming to the paper medium such as a plastic sheet. Also, the print medium may not be printed at all. In addition, any printing necessary in the process of sending the printing medium received by the printing medium input unit 101 to the frame border applying device 102 via the conveyance unit 107 may be performed.

  The frame edge applying device 102 recognizes the entire print medium received by the print medium input unit 101 via the transport unit 107 by an arbitrary method such as a camera incorporated in the frame edge applying device 102. Further, when the frame border applying device 102 recognizes the entire printing medium, the printing medium detected by any method using a printing device such as a printer built in the frame border applying device 102 with respect to the print medium. Overwrite the rectangular border on the edge of. Note that the thickness and color of the rectangular frame line are determined in advance, and for example, white, black, or a color combining them can be set as the color. Further, the frame edge applying device 102 conveys the printing medium on which the rectangular frame line is overprinted to the emboss ID embedding device 103 via the conveying unit 107. The printed rectangular frame is added to specify the position of the digital watermark pattern from the camera capture image at the time of digital watermark detection.

  When the embossed ID embedding device 103 recognizes the entire print medium, which is conveyed through the conveyance unit 107 and overwritten by the frame edge applying device 102, by a camera or the like incorporated in the embossed ID embedding device 103, the print medium The entire image is photographed and output to the pattern generation device 105. Further, when the embossed ID embedding device 103 receives a binarized linear digital watermark pattern from the pattern generation device 105, the embossed ID embedding device 103 receives an embossing type called an embosser which is a part of the embossed ID embedding device 103. To adapt to the digital watermark pattern. Here, adapting to the digital watermark pattern means changing to an embosser that forms the asperities of the digital watermark pattern on the surface.

  In addition, the embossing ID embedding device 103 performs sanding from both sides of the target printing medium using the embossing machine embedded in the embossing ID embedding device 103, using the modified embosser. And embossing the surface of the digital watermark pattern so as to form asperities on the surface, and embedding the digital watermark pattern. Further, the emboss ID embedding device 103 transports the print medium in which the digital watermark pattern is embedded to the print media output unit 104 via the transport unit 107. In the first embodiment, the emboss ID embedding device 103 embeds the digital watermark pattern so as to fit within the frame border rectangle printed on the print medium.

  As described above, the embossing in the first embodiment is realized by taking a mold called an embosser and sanding the target print medium from both sides with a embossing machine or the like. In the first embodiment, the embosser is made of acrylic resin or the like, but the embosser is not limited to this. Also, a 3D printer may be used to create a mold.

  The print medium output unit 104 physically outputs the print medium having the digital watermark embedded therein, which is conveyed through the conveyance unit 107.

  The control unit 106 controls the print medium input unit 101, the frame edge applying device 102, the emboss ID embedding device 103, the print medium output unit 104, the pattern generation device 105, and the transport unit 107.

  The pattern generation device 105 can be configured by a computer including a CPU, a RAM, and a ROM storing a program for executing a pattern generation routine described later and various data. The pattern generation device 105 functionally includes an input unit 200, an operation unit 202, and an output unit 210, as shown in FIG.

  The input unit 200 receives, from the emboss ID embedding device 103, image data of the entire printed material photographed by the emboss ID embedding device 103.

  The arithmetic unit 202 includes a digital watermark pattern generation unit 204 and a binarization processing unit 206.

  The electronic watermark pattern generation unit 204 receives an image size (at least W × H pixel size of the entire print medium) representing the entire print medium photographed by the emboss ID embedding device 103 received by the input unit 200, and the photographed print medium The digital watermark pattern is generated based on the k-bit digital watermark information ID which is the embedded information stored in the memory (not shown) corresponding to B, and is output to the binarization processing unit 206. In the first embodiment, a method of generating a digital watermark pattern to be a type uses, for example, the method disclosed in Non-Patent Document 1. The information to be embedded in the first embodiment is ID information. Further, information to be embedded corresponding to the photographed print medium can be obtained by any method.

Specifically, first, error correction and error detection coding are performed on the acquired k-bit digital watermark information ID to obtain an n-bit post-code Code. Next, using a predetermined integer value N, a sequence of length N ² obtained by repeating each bit value c _j of code after code l = N ² / n times and repeating it is represented by the following equation (1) Do.

  Also, a pseudorandom number sequence of length l

And j = 0. . . A series of length N ² prepared for n-1 and arranging these is set as the following equation (2).

  Next, direct diffusion modulation is performed according to the following equation (3).

However, the value of b _i is calculated by reading “−1” when the bit value “0” and “+1” when the bit value “1”. Next, a pseudorandomly determined substitution represented by the following equation (4) is prepared.

Further, the scrambled sequence {t _i } is calculated according to the following equation (5) by scrambling the sequence of {s _i } using the permutation of the equation (4).

  Here, scrambling has an effect as interleaving coding, and contributes to preventing an imbalance in the resistance among bits.

Next, two two-dimensional sine curves P ⁻ = {P ⁻ _{x, y} } of 90 degree rotational symmetry, and P ⁺ = {{with the relative frequencies to the image size are (Freq, Freq) and (Freq,-Freq) Block image group by generating P ⁺ _{x, y} } and dividing it into N × N blocks respectively

To get Then, for each block position in the block division (h, v), along the raster scan order of blocks selecting the section embedded sequence _{t i (i = h + vN} ), the electronic watermark pattern in accordance with the value of t _i The block image P ^{(h, v)} _{x, y} is selected as in the following equation (6).

By performing this process for all block positions (h, v), a linear watermark pattern P = {P _{x, y} } of W × H pixels represented by multivalued pixel values is generated.

  A binarization processing unit 206 binarizes the acquired linear digital watermark pattern, converts the binarized linear digital watermark pattern converted into an embossable shape, and outputs the digital watermark pattern to the output unit 210. The information is output to the emboss ID embedding device 103 via the output unit 210.

  Here, the reason for performing the binarization process will be described. The digital watermark pattern represented by Non-Patent Document 1 can not be used as it is when processing the print medium as emboss as it is, as in the first embodiment, since all digital watermark patterns are represented as multi-valued patterns. . Therefore, in the first embodiment, the digital watermark pattern generated with the multi-level pattern is subjected to binarization processing, and is converted into the digital watermark pattern of the embossable binary pattern.

  Specifically, a fixed threshold value is provided for the digital watermark pattern, and pixel values larger than the threshold value are converted to 1 and other pixel values are converted to 0. By doing this, it can be converted into a binary pattern. However, by converting a multi-valued pattern into a binary pattern, the portion where the pixel value changes smoothly is crushed, and the amount of information as image data is lost. Therefore, there is a high possibility that conversion to a detectable pattern can not be made even if the threshold value for binarization is arbitrarily set.

  Therefore, in the first embodiment, the maximum value (maximum pixel value) and the minimum value (minimum pixel value) of all the pixel values constituting the digital watermark pattern are determined, and their intermediate value ((maximum value + minimum) Binarization is performed with the value) / 2) as the threshold value. In the digital watermark method as in Non-Patent Document 1, the gradation of the pattern is represented by a smoothly changing sine wave such that the spatial frequency of the stripe pattern becomes constant so as to be less visible. The ID information to be shown is represented by the shape of the pattern itself (specifically, the frequency of the wave represented by the pattern).

  Furthermore, since the digital watermark pattern is extracted based on the frequency in the detection of the digital watermark pattern, the ID information itself is not lost if the shape of the pattern is stored. By using a method in which an intermediate value of all pixel values of the digital watermark pattern is used as a threshold value, it can be converted into a rectangular wave having the same frequency as a sine wave, and therefore, binarization can be performed while holding ID information indicated by the pattern.

<Configuration of Information Detection Device According to First Embodiment>
Next, the configuration of the information detection apparatus according to the first embodiment will be described. As shown in FIG. 6, the information detection apparatus 300 according to the first embodiment is a computer including a CPU, a RAM, and a ROM storing a program for executing a detection processing routine to be described later and various data. It can be configured. The information detection apparatus 300 functionally includes a camera input unit with auxiliary illumination 310, an operation unit 320, and a result output unit 390 as shown in FIG.

  The camera input unit with auxiliary illumination 310 photographs a target printed matter using a digital camera or the like which is a photographing device, and receives each image of digital data. In the first embodiment, light is sequentially emitted at different angles from a plurality of places (two or more places may be used) using a light source provided in the camera input unit with auxiliary illumination 310 and a digital camera. Every time the illumination angle is changed (for each lighting environment), an image is taken. For example, in the case of the configuration as shown in FIG. 7, the light source 1 is turned on and the light source 2 is turned off, and shooting is performed once. Next, the light source 1 is turned off, and the light source 2 is turned on once. Then, the light source 1 is turned off, and the light source 2 is turned off, and shooting is performed once. Thereby, a plurality of images with different light irradiation angles can be obtained. Also, separately from this, the light source may be single, the shooting angle of the camera may be changed a plurality of times, and shooting may be performed once, or a plurality of cameras may be installed in advance so as to be able to shoot from different angles in advance. You may make it the system to image | photograph to.

  The calculation unit 320 includes a frame edge detection geometric correction unit 322, a difference image calculation unit 324, an unevenness degree determination unit 326, and an emboss ID detection unit 328.

  The frame edge detection geometric correction unit 322 determines the position of the rectangular frame line included in the image for each of the images received by the camera input unit with auxiliary illumination 310, and the definition seen from the front based on the rectangular frame line Projective transform to an image of size. Thus, regardless of the shooting angle of the camera, projective transformation distortion can be corrected and normalized to an image of a predetermined size. A specific method used in frame edge detection in the first embodiment utilizes the frame edge detection method shown in Non-Patent Document 1 or the like.

  The difference image calculation unit 324 creates an image pair for all the combinations of images based on each of the images normalized by the frame edge detection geometric correction unit 322. In addition, the difference image calculation unit 324 calculates, for each of the created image pairs, a difference image by calculating the difference between the pixel values of each image included in the image pair.

  In addition, when the number of times of photographing at the time of camera input is N times, N × (N−1) / 2 pairs of images are created, so N × (N−1) / 2 pairs of difference images can be obtained. it can. In addition, since it is necessary to equalize the overall brightness when calculating the difference, it is necessary to adjust the average value of the pixel values to be a predetermined numerical value.

  Further, the difference image calculation unit 324 selects, from each of the calculated difference images, a difference image having the largest sum of absolute values of pixel values of the difference image, and selects the selected difference image as the unevenness degree determination unit. Output to 326.

  When the sum of absolute values of pixel values of the difference image acquired by the difference image calculation unit 324 is larger than a predetermined threshold value, the unevenness degree determination unit 326 determines that the shadow generated by the unevenness has been detected, The determination result is output to the embossing ID detection unit 328.

  In addition, when the sum of absolute values of pixel values of the difference image acquired by the difference image calculation unit 324 is smaller than a predetermined threshold, the unevenness degree determination unit 326 determines that the shadow generated by the unevenness is not detected. The determination result is output from the result output unit 390.

  Note that, in addition to the determination method as described above, the embossing ID detection is performed directly from the plurality of images normalized by the frame edge detection geometric correction unit 322, and as a result, when illumination is applied from the front of the printing medium, detection If it can not be detected and illumination can be detected when the illumination is applied from an oblique direction, it may be determined that the shadow generated by the unevenness can be detected.

  The emboss ID detection unit 328 detects an emboss ID embedded as a digital watermark from the difference image acquired by the difference image calculation unit 324. As the digital watermark detection method, for example, the method disclosed in Non-Patent Document 1 can be used. This utilizes the fact that it is possible to filter only the shadow pattern produced by embossing by the difference image. By using this method, only the concavo-convex pattern represented by the concavities and convexities can be targeted for watermark detection, so that the effect of improving the detection accuracy can be expected. However, the emboss ID may be detected using the image normalized by the frame edge detection geometric correction unit 322 as it is without using the difference image.

  The result output unit 390 outputs, as a final result, the determination result of the unevenness degree determination unit 326 or the emboss ID detected by the emboss ID detection unit 328. In the output, the information is displayed on a display or the like, or output as data to a memory or the like.

<Operation of Pattern Generation Device According to First Embodiment>
Next, the operation of the pattern generation device 105 according to the first embodiment will be described. When the pattern generation device 105 receives the image data of the entire printing medium from the emboss ID embedding device 103, the CPU executes a program stored in the ROM of the pattern generation device 105, whereby the pattern generation processing routine shown in FIG. Run.

  First, in step S100, the k-bit digital watermark information ID corresponding to the acquired image data stored in the memory is read.

  Next, in step S102, a digital watermark pattern is generated based on the k-bit digital watermark information ID acquired in step S100 and the received image size representing the entire print medium.

  Next, in step S104, the digital watermark pattern acquired in step S102 is binarized.

  Next, in step S106, the digital watermark pattern subjected to the binarization processing acquired in step S104 is output through the output unit 210, and the pattern generation processing routine is ended.

<Operation of Information Detection Device According to First Embodiment>
Next, the operation of the information detection apparatus 300 according to the first embodiment will be described. The information detection apparatus 300 stores in the ROM of the information detection apparatus 300 when the camera input unit 310 with auxiliary illumination receives each of the images of digital data captured every time the imaging environment is changed in the target printed material. The CPU executes the program to execute the detection processing routine shown in FIG.

  First, in step S200, for each of the acquired images, the position of the rectangular frame included in the image is obtained, and projective transformation is performed to an image of a prescribed size viewed from the front based on the rectangular frame.

  Next, in step S202, based on each of the projective-transformed images acquired in step S200, an image pair is created for all the image combinations.

  Next, in step S204, a difference image is calculated for each of the image pairs acquired in step S202.

  Next, in step S206, based on each of the difference images acquired in step S204, a difference image having the largest sum of absolute values of pixel values of the difference image is selected.

  Next, in step S208, based on the difference image selected in step S206, it is determined whether the sum of the absolute values of the pixel values of the difference image is larger than a predetermined threshold. If the total value is larger than the predetermined threshold value, the detection processing routine proceeds to step S210. On the other hand, if the total value is equal to or less than the predetermined threshold value, the detection processing routine proceeds to step S300.

  Next, in step S210, the emboss ID embedded as a digital watermark is detected from the difference image acquired in step S206.

  Next, in step S212, the emboss ID acquired in step S210 is output as a final result, and the detection processing routine is ended.

  In step S300, the determination result that the shadow generated due to the unevenness is not detected is output as the final result, and the detection processing routine is ended.

  As described above, according to the information detection apparatus according to the first embodiment, the medium is photographed for each illumination environment, acquired as digital data, and an image pair is created based on each of the acquired images. Calculating the difference image for each of the image pairs, calculating the sum of the absolute values of the pixel values of the difference image for each of the difference images, and selecting the difference image having the largest calculated sum Based on the total value of the selected difference image and a predetermined threshold value, it is determined whether or not the shadow generated by the unevenness can be detected, and when it is determined that the shadow can be detected, the selected difference image is selected. By detecting the ID information embedded as the concavo-convex pattern, the ID information can be accurately detected from the concavo-convex pattern formed on the medium.

  In addition, since the ID information is embedded by applying embossing processing to the print medium and recording the digital watermark pattern, even the digital copier can not copy the digital watermark pattern even by a general copying machine. Further, since a camera having a plurality of illumination light sources is used to detect its ID information, only a shadow pattern by embossing can be extracted, and a two-dimensionally forged digital watermark pattern can be excluded. As a result, it is possible to provide a method for creating watermarked print media that is difficult to copy.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made without departing from the scope of the present invention.

  Next, an information embedding system and an information detecting device according to the second embodiment will be described.

  In the second embodiment, the emboss ID is embedded in the printing medium on which the two-dimensional code is printed, and the camera detects the two-dimensional code and the emboss ID, and the authenticity determination of the two-dimensional code is performed. It differs from the first embodiment. In addition, about the structure and effect | action similar to the information embedding system 100 which concerns on 1st Embodiment, and the information detection apparatus 300, the same code | symbol is attached | subjected and description is abbreviate | omitted.

<Configuration of Information Embedding System According to Second Embodiment>
First, the configuration of the information embedding system according to the second embodiment will be described. As shown in FIG. 10, the information embedding system 400 according to the second embodiment includes a print medium input unit 101, a frame edge providing device 102, an emboss ID embedding device 403, a print medium output unit 104, and pattern generation. An apparatus 405, a control unit 406, and a transport unit 107 are provided. In the second embodiment, a two-dimensional code is printed on the print medium received.

  When the emboss ID embedding device 403 recognizes the entire print medium, which is conveyed through the conveyance unit 107 and overwritten by the frame edge giving device 102, by the camera etc. embedded in the emboss ID embedding device 403, the print medium The entire image is taken and output to the pattern generation device 405. In the second embodiment, the entire print medium is photographed, and simultaneously, the two-dimensional code printed on the print medium is read, and the ID information represented by the two-dimensional code is also output to the pattern generation device 405.

  Further, when the embossed ID embedding device 403 receives a binarized linear digital watermark pattern from the pattern generation device 405, the embosser which is a part of the embossed ID embedding device 403 is adapted to the received digital watermark pattern To change.

  In addition, the embossing ID embedding device 403 sands the target printing medium using the modified embosser from both sides of the printing medium using the embossing machine built in the embossing ID embedding device 403. And embossing the surface of the digital watermark pattern so as to form asperities on the surface, and embedding the digital watermark pattern. Further, the emboss ID embedding device 403 transports the print medium in which the digital watermark pattern is embedded to the print media output unit 104 via the transport unit 107. In the second embodiment, the emboss ID embedding device 403 embeds the digital watermark pattern so as to overlap the two-dimensional code printed on the print medium.

  The control unit 406 controls the print medium input unit 101, the frame edge applying device 102, the emboss ID embedding device 403, the print medium output unit 104, the pattern generation device 405, and the transport unit 107.

  The pattern generation device 405 can be configured by a computer including a CPU, a RAM, and a ROM storing a program for executing a pattern generation routine described later and various data. The pattern generation device 405 functionally includes an input unit 500, an arithmetic unit 502, and an output unit 510 as shown in FIG.

  The input unit 500 receives, from the emboss ID embedding device 403, the image size of the entire print taken by the emboss ID embedding device 403, and the ID information represented by the two-dimensional code printed on the printing medium.

  The operation unit 202 includes a short code generation unit 503, a digital watermark pattern generation unit 504, and a binarization processing unit 206.

  The shortening code generation unit 503 generates a shortening code obtained by a hash function or the like based on the ID information represented by the two-dimensional code printed on the print medium received by the input unit 500, and generates the digital watermark pattern Output to unit 504.

  The digital watermark pattern generation unit 504 acquires the image size of the entire print medium (W × H pixel size of the entire print medium) captured by the emboss ID embedding device 403 accepted by the input unit 500 and the reduced code generation unit 503 A digital watermark pattern is generated based on the short code and output to the binarization processing unit 206. In the second embodiment, the shortening code is an emboss ID, which is ID information to be embedded, and is k-bit.

<Configuration of Information Detection Device According to Second Embodiment>
Next, the configuration of the information detection apparatus according to the second embodiment will be described. As shown in FIG. 12, an information detection apparatus 600 according to the second embodiment is a computer including a CPU, a RAM, and a ROM storing a program for executing a detection processing routine described later and various data. It can be configured. This information detection apparatus 600 functionally includes a camera input unit with auxiliary illumination 610, an operation unit 620, and a result output unit 690, as shown in FIG.

  The camera input unit with auxiliary illumination 610 captures an image of a target print medium using a digital camera or the like, which is an imaging device, and receives each image of digital data. Further, the camera input unit with auxiliary illumination 610 acquires ID information represented by the two-dimensional code from the two-dimensional code printed on the target print medium based on an arbitrary method.

  The calculation unit 320 includes a frame edge detection geometric correction unit 322, a difference image calculation unit 324, an unevenness degree determination unit 326, a shortening code generation unit 622, an emboss ID detection unit 624, and a determination unit 626. It is done.

  The shortening code generation unit 622 generates a shortening code by the same method as the shortening code generation unit 503 described above on the basis of the ID information represented by the two-dimensional code acquired by the camera input unit with auxiliary illumination 610, and the determination unit Output to 626.

  The emboss ID detection unit 624 detects an emboss ID embedded as a digital watermark from the difference image acquired by the difference image calculation unit 324, and outputs the emboss ID to the determination unit 626.

  The determination unit 626 compares the shortening code acquired from the shortening code generation unit 622 with the emboss ID acquired from the emboss ID detection unit 624, and outputs the emboss ID as a final result to the result output unit 690 when they match. Do. On the other hand, when they do not match, a result to the effect that they do not match is output to the result output unit 690 as the final result.

  The result output unit 690 outputs the determination result of the unevenness degree determination unit 326 or the determination result of the determination unit 626.

<Operation of Pattern Generation Device According to Second Embodiment>
Next, the operation of the pattern generation device 405 according to the second embodiment will be described. When the pattern generation device 405 receives the image data of the entire printing medium and the data represented by the two-dimensional code from the emboss ID embedding device 403, the CPU executes the program stored in the ROM of the pattern generation device 405 By doing this, the pattern generation processing routine shown in FIG. 13 is executed.

  First, in step S400, a shortened code obtained by a hash function or the like is generated based on the ID information represented by the received two-dimensional code.

  Next, in step S402, a digital watermark pattern is generated based on the shortening code acquired in step S400 and the received image size of the entire print medium.

<Operation of Information Detection Device According to Second Embodiment>
Next, the operation of the information detection apparatus 600 according to the second embodiment will be described. In the information detection apparatus 600, in the camera input unit with auxiliary illumination 610, each of the images of digital data captured every time the imaging environment is changed, and the two-dimensional code printed on the print media When the ID information to be expressed is received, the CPU executes a program stored in the ROM of the information detection apparatus 600 to execute a detection processing routine shown in FIG.

  In step S500, based on the ID information represented by the acquired two-dimensional code, a shortened code is generated using the same method as step S400 described above.

  Next, in step S502, it is determined whether the emboss ID acquired in step S210 matches the shortening code acquired in step S500. If the emboss ID matches the shortening code, the detection processing routine proceeds to step S504. On the other hand, if the emboss ID and the shortening code do not match, the detection processing routine proceeds to step S506.

  Next, in step S504, the emboss ID acquired in step S210 is output as a final result from the result output unit 690, and the detection processing routine is ended.

  In step S506, the detection processing routine output from the result output unit 690 as an end result that the emboss ID and the shortening code do not match is ended.

  As described above, according to the information detection apparatus according to the second embodiment, it is possible to create a system for performing the authenticity determination of a two-dimensional code.

  Further, at the time of detection, the authenticity judgment can be realized by collating the shortening code obtained from the two-dimensional code and the shortening code obtained from the emboss ID. Further, according to the information detection apparatus according to the second embodiment, since duplication by the copying machine can be suppressed, it is possible to guarantee the authenticity of the printed two-dimensional code with high accuracy. A one-dimensional barcode may be used instead of the two-dimensional code.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made without departing from the scope of the present invention.

  For example, in the first and second embodiments, the case where the frame border applying device overwrites the rectangular frame line on the input print medium frame has been described, but the present invention is not limited to this. For example, in the case of using a digital watermark method capable of specifying the position of the digital watermark pattern even without a frame, the above-described frame edge providing device and the frame edge detection geometric correction unit may be omitted. However, in the case of using a digital watermark method capable of specifying the position of the digital watermark area even without a frame, the frame edge providing device 102 and the frame edge detection geometric correction unit 322 may be omitted.

  Further, in the first and second embodiments, the case where the frame border applying device overwrites the rectangular frame line on the frame of the input print medium has been described, but the present invention is not limited to this. For example, the addition is not limited to a frame, and a specific pattern or the like such as a cutout symbol of QR code (registered trademark) may be added. However, in this case, it is necessary to replace the processing in the above-mentioned frame edge detection geometric correction unit with a detection method corresponding to a specific pattern or the like.

  In the first and second embodiments, the process of embedding the digital watermark is mainly described in the case of assuming a paper medium, but the present invention is not limited to this. For example, a 3D printer may be used to generate and output a molded product. In this case, the print medium input unit 101 may be configured to digitally input shape data of an object, and process the frame border providing device 102 and the emboss ID embedding device 103 as data.

  In the first and second embodiments, in the information embedding system, in each of the frame edge providing device and the emboss ID embedding device, the print medium is photographed or photographed using a camera or the like and recognized. However, the present invention is not limited to this. For example, the rectangular border may be printed on the printing medium in the border applying device based on the information (pixel value, size, etc.) of the printing medium received in the printing medium input unit and the transport speed of the transport unit. The digital watermark pattern may be generated in the pattern generation device.

  In the first and second embodiments, the embossing ID embedding device 103 has been described as being embedded so as to fit within the frame edge rectangle printed on the printing medium, but the present invention is not limited to this. For example, the digital watermark pattern may be embedded in the corresponding arbitrary area based on the frame edge rectangle, the predetermined frame edge rectangle, and the positional relationship. Also, the size of the embedded pattern to be embedded may be any predetermined size.

  Moreover, in the first and second embodiments, the case where the target print medium is not determined in advance has been described, but the present invention is not limited to this. For example, a target print medium may be determined in advance, and the above-described processing may be performed on the print medium. In this case, the rectangular frame line may be printed on the print medium by the frame edge applying device based on the information (size etc.) of the print medium determined in advance and the transport speed of the transport unit. In addition, a digital watermark pattern corresponding to a print medium predetermined in the pattern generation apparatus may be generated in advance. Further, in the emboss ID embedding device 103, it may be changed in advance to an embosser corresponding to a predetermined print medium.

  Moreover, in the first and second embodiments, the case where the embosser is changed for each process has been described, but the present invention is not limited to this. For example, when the target print medium is determined in advance, it may be changed to the corresponding embosser in advance. Alternatively, blocks of a plurality of uneven patterns may be prepared, and an embosser corresponding to a printing medium may be formed by combining the blocks of the uneven patterns.

  Also, if it is only necessary to receive the copy suppression effect by embedding by embossing, in order to simplify the digital watermark detection process, instead of irradiating multiple light sources in order, a single image is photographed with only ambient light and embossed ID May be detected. In this case, any method may be used to detect the emboss ID. Moreover, when using an arbitrary method, the process of the above-mentioned difference image calculation part 324 and the unevenness degree judgment part 326 may be abbreviate | omitted.

  Furthermore, although the present invention has been described as an embodiment in which the program is installed in advance, the program can be provided by being stored in a computer readable recording medium, and provided via a network. It is also possible.

100, 400 Information embedding system 101 Print medium input unit 102 Frame border giving device 103, 403 Embossed ID embedding device 104 Print medium output unit 105, 405 Pattern generation device 106, 406 Control unit 107 Conveying unit 200, 500 Input unit 202, 502 Operation unit 204, 504 Digital watermark pattern generation unit 206 Binarization processing unit 210, 510 Output unit 300, 600 Information detection device 310, 610 Camera input unit with auxiliary illumination 320, 620 Operation unit 322 Frame edge detection geometric correction unit 324 Difference Image calculation unit 326 Concavo-convex degree determination unit 328, 624 Embossed ID detection unit 390, 690 Result output unit 503 Short code generation unit 622 Short code generation unit 626 Determination unit

Claims (3)

A digital watermark pattern generation unit that generates a linear digital watermark pattern represented by multivalued pixel values based on embedded information that is ID information;
The intermediate value of the maximum pixel value and the minimum pixel value of the linear digital watermark pattern is used as a threshold based on each pixel value of the linear digital watermark pattern generated by the digital watermark pattern generation unit. A binarization processing unit that generates a binarized linear digital watermark pattern obtained by binarizing each pixel value of the linear digital watermark pattern;
A media input unit for physically inputting media ;
The embosser, which is a mold for embossing, is changed so as to form the unevenness of the generated linear digital watermark pattern, and an arbitrary area of the surface of the medium input by the medium input unit respect, said the modified embosser, embossed ID embedding unit for processing the medium,
Information embedding devices , including: A method for embedding information in an information embedding apparatus, comprising an electronic watermark pattern generation unit, a binarization processing unit, a medium input unit, and an emboss ID embedding unit,
The digital watermark pattern generation unit generates a linear digital watermark pattern represented by multivalued pixel values based on embedded information which is ID information;
The binarization processing unit is based on each pixel value of the linear digital watermark pattern generated by the digital watermark pattern generation unit, between the maximum pixel value and the minimum pixel value of the linear digital watermark pattern Generating a binarized linear digital watermark pattern by binarizing each pixel value of the linear digital watermark pattern, using a value as a threshold;
The medium input unit physically inputs a medium,
The emboss ID embedding unit changes the embosser, which is a mold for emboss processing, so as to form the concavities and convexities of the generated binarized linear digital watermark pattern, and the embosser is input by the medium input unit. A method of embedding information on an arbitrary area of a surface of a medium , wherein the medium is processed by the modified embosser . A program for a computer to function as each unit of the information embedding equipment according to claim 1 Symbol placement.