JP4143625B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to an image processing apparatus and an image processing method for synthesizing and outputting a copy-suppressed copy-forgery-inhibited pattern on a document for the purpose of suppressing illegal forgery and information leakage caused by copying an important document.

  Receipts, securities, and certificates may have a special pattern printed on the background that makes characters and images appear when copied so that they are not easily copied. This special pattern, including the latent image portion and the background portion, is generally called a forgery-suppressing tint block. This is a pattern in which the original cannot be easily copied by copying. By applying this pattern to the original, psychologically, the act of copying the original and forging the original is suppressed. To achieve the effect.

  The forgery-preventing copy-forgery-inhibited pattern is composed of two areas having the same density, an area where dots remain after copying and an area where dots disappear after copying. These two areas have almost the same average density, and macroscopically, it is not obvious that characters and images such as “copy” are hidden, but microscopically have different characteristics. Yes. In the present invention, this hidden character or image is called a latent image as distinguished from the background.

  For example, an area in which dots remain after copying (called a latent image portion) is composed of clustered dots in which each dot is concentrated, and an area in which dots disappear after copying (called a background portion) is a dot in which each dot is dispersed. By constructing, it is possible to create two regions having substantially the same concentration and different characteristics.

  Concentrated dots and dispersed dots can be generated in image processing by halftone processing using halftone dots having different numbers of lines or dither processing using dither matrices having different characteristics.

  In the halftone processing, it is preferable to use a halftone dot with a low line number to obtain a concentrated dot arrangement, and use a halftone dot with a high line number to obtain a dispersed dot arrangement.

  In dither processing using a dither matrix, a dot concentrated dither matrix is preferably used to obtain a concentrated dot arrangement, and a dot distributed dither matrix is preferably used to obtain a dispersed dot arrangement.

  Therefore, when generating a tint block image using halftone processing, the latent image portion is suitable for halftone processing with a low number of lines, and the background portion is suitable for halftone processing with a high number of lines. In the case of generation, dither processing using a dot concentration type dither matrix is suitable for the latent image portion, and dither processing using a dot dispersion type dither matrix is suitable for the background portion.

  In general, a copying machine has a limit of image reproduction capability that depends on an input resolution for reading minute dots of a copied document and an output resolution for reproducing minute dots. Therefore, if there are isolated minute dots in the document that exceed the limit of the image reproduction capability of the copying machine, the minute dots cannot be completely reproduced in the copied material, and the isolated minute dot portions are lost. .

  Therefore, if the background of the forgery-inhibited background pattern is created to exceed the limit of dots that can be reproduced by a copying machine, large dots (concentrated dots) in the forgery-inhibited background pattern can be reproduced by copying, but small dots (distributed) (Dot) cannot be reproduced, and a hidden image (latent image) appears. In addition, even if the dispersed dots do not disappear completely by copying, the density difference after copying is clearly different from the concentrated dots, resulting in a hidden image (latent image) from the human eye. It will appear to emerge.

  Also, a technique called “camouflage” that makes it difficult to distinguish a hidden character or image (latent image) from a forgery-inhibited tint block is well known.

  The camouflage has a different density from the latent image part and background part, and a finer pattern part than the latent image part is placed on the entire forgery-inhibited tint block image including the latent image part and the background part (additional) At first glance, macroscopically, the contrast between the camouflage and the latent image portion or the background portion is emphasized rather than the contrast between the latent image portion and the background portion, so that the camouflage pattern stands out and the latent image or This has the effect of making the outline of the latent image less noticeable.

  In addition, compared to a counterfeit pattern having no camouflage pattern, the counterfeit pattern having a camouflage pattern has an effect of giving a decorative impression to the printed matter.

  In the camouflage pattern, it is desirable that dots in the camouflage pattern disappear as much as possible after copying so that the latent image can be easily distinguished after copying. In the simplest implementation, camouflage can be achieved by not hitting dots at locations corresponding to the camouflage pattern. Needless to say, a dot is hit around the portion where the dot is not hit, and the dots have different ways of hitting in the case of the latent image portion and the background portion.

  The above is the outline of the counterfeit copy-forgery pattern.

  Conventionally, printing paper manufacturers have previously printed a copy-forgery-inhibited pattern including characters and images (latent images) such as “copy” on dedicated paper and sold it as anti-copy paper. Then, government offices and companies purchased copy-preventing paper and printed on the copy-preventing paper to prevent the copy of the printed matter from being printed.

  However, conventional copy prevention paper is created by printing paper manufacturers by preprinting the background pattern on special paper, so the cost of using special paper, the cost caused by preparing more than the required number of preprinted paper, etc. There was a demerit in cost.

  However, in recent years, a technique for creating a forgery-inhibited tint block image in software and outputting a document in which a forgery-inhibiting tint block is placed on the background by a laser printer (in the present invention, this is referred to as an on-demand tint block output method using a printer). ) Is realized (see Patent Document 1).

  With the on-demand copy-forgery-inhibited pattern output method using a printer, it is possible to print a document with forgery-suppressed copy-forgery-inhibited patterns placed on the background using plain paper. be able to. Therefore, it is not necessary to prepare copy prevention sheets more than necessary as in the prior art. Therefore, in the on-demand copy-forgery-inhibited pattern output method using a printer, the cost for paper can be significantly reduced as compared with a conventional document copy suppression method using copy-preventing paper.

  Further, users of conventional copy protection paper can only use hidden characters and images (latent images) prepared in advance, or hidden characters and images (latent images) ordered on a custom-made basis.

JP 2001-197297 A

  In the copy of the base paper that has a counterfeit copy-forgery pattern, the raised pattern appears to clearly distinguish the copy from the original, and at the same time, the copy alone can clearly be copied. It has features that can be distinguished. In addition, it is possible to prevent receiving the copied material as a base paper, and to expect psychological deterrence of trying to use the copied material as the base paper. However, an image of a forgery-inhibited tint block pattern is generally generated with a dot pattern and is synthesized on the entire content image, in order to determine information related to the output material, for example, output device information, output person name, etc. There is a problem that it is not possible to secure an area for expressing the digital information such as the digital information and the digital signature information on the printed paper.

  It is possible to embed such information in the output by synthesizing a two-dimensional barcode etc. into a part of the content image, but in this case, it is necessary to control so that the background pattern image does not overlap the two-dimensional barcode. In addition, the tint block image generation process and the synthesizing process become very complicated. In addition, if there is a region where the copy-forgery-inhibited pattern image does not exist, the aesthetic appearance is also impaired.

  In view of these problems, the present invention has an object to provide an apparatus and a method for generating a forgery-inhibited tint block that has a function of forgery-inhibiting tint block and that has digital information embedded therein.

In order to achieve the above object, the image processing apparatus of the present invention arranges a plurality of types of white patterns indicating information according to shapes based on information (bit strings) to be embedded, thereby providing a white pattern attached. A generating unit that generates a tint block image; and a synthesizing unit that synthesizes a tint block image with a white pattern generated by the generating unit with an input image, and the white pattern is a latent image included in the tint block image The generating means is a bit corresponding to the white pattern in the information (bit string) to be embedded in the shape of each white pattern included in the plurality of white patterns. formed to be based on, the white pattern is placed on a specific area on the basis of the information (bit string) for embedding said, and the specific region, latent in the background pattern image The generation means arranges the plurality of types of white patterns in a latent image area based on the information to be embedded, and the generation means further includes the plurality of types of white patterns. In the background pattern image, it is arranged in the background area .

Further, the generation means arranges the plurality of types of white patterns in a background area based on the generated random number.

Further, the generation means, a camouflage area designation image generation means for generating a camouflage area designation image by arranging a plurality of types of white patterns indicating information by shape on a specific area based on information to be embedded; A tint block for generating a tint block image with a white pattern based on the camouflage region designation image generated by the camouflage region designation image generating unit, the binary pattern for the latent image portion, and the binary pattern for the background portion. And an image generation means.

  Furthermore, it has an input means for inputting arbitrary information, and the information to be embedded is information generated by making the information input by the input means redundant. is there.

The image processing apparatus control method according to the present invention generates a tint block image with a white pattern by arranging a plurality of types of white patterns indicating information according to shapes based on information to be embedded (bit strings). And a synthesis step of synthesizing the background pattern image with the white pattern generated in the generation step with the input image, wherein the white pattern makes the outline of the latent image included in the background pattern image conspicuous The generation step is configured so that the shape of each white pattern included in the plurality of white patterns is based on a bit corresponding to the white pattern in information to be embedded (bit string). formed, the white pattern is placed on a specific area on the basis of the information for embedding the (bit string), the the specified region, that of the latent image area in the copy-forgery-inhibited pattern image The generating step arranges the plurality of types of white patterns in the latent image area based on the information to be embedded, and the generation step further includes the plurality of types of white patterns in the copy-forgery-inhibited pattern image. It is arranged in the background area .

Further, the generating step is characterized in that the plurality of types of white patterns are arranged in a background area based on the generated random number.
Further, the generation step includes a camouflage region designation image generation step of generating a camouflage region designation image by arranging a plurality of types of white patterns indicating information according to shape on a specific region based on information to be embedded, and A tint block for generating a tint block image with a white pattern based on the camouflage region designation image generated by the camouflage region designation image generating unit, the binary pattern for the latent image portion, and the binary pattern for the background portion. And an image generation step.
Furthermore, it has an input step for inputting arbitrary information, and the information to be embedded is information generated by making the information input in the input step redundant.
Further, the present invention is a program to be executed by a computer, and is a computer program for causing a computer to execute the control method according to any one of claims 5 to 8 .

  According to the present invention, since it is possible to express arbitrary information with a camouflage pattern that constitutes a forgery-inhibiting tint block, for example, information related to output operations and output items can be expressed as a forgery-inhibiting tint block that does not impair the aesthetics. Can be generated. Furthermore, by applying such a camouflage pattern to an area reproduced in a copy, it is possible to obtain arbitrary information from the copy, and to enable tracking from the copy.

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

  The present embodiment relates to digital information expression using camouflage in a forgery-suppressing tint block. As a result, in addition to the original function of anti-counterfeiting tint block such as psychological deterrence of illegal copying, the point of the present invention is that other security-related functions such as falsification detection data and electronic signature can be realized.

(Overview of on-demand background printing system)
First, the outline of the on-demand copy-forgery-inhibited pattern printing system will be described with reference to FIG. FIG. 1 shows an outline of a general configuration of a computer system as an embodiment that can be used as the image processing apparatus of the present invention or that can implement the image processing method of the present invention. Yes.

  The on-demand copy-forgery-inhibited pattern printing system is a system that implements the on-demand copy-forgery-inhibited pattern output method described in “Prior Art”, and uses, for example, a general PC and printer configuration as shown in FIG. Can be realized.

  Here, how each unit shown in FIG. 1 functions when an on-demand copy-forgery-inhibited pattern printing system is realized with such a configuration will be described.

  In the figure, reference numeral 111 denotes a CPU, which controls the entire computer using programs and data stored in a RAM 112 and a ROM 113 and performs each process described in the embodiments described later. .

  The RAM 112 has an area for temporarily storing programs and data loaded from the external storage device 118 and programs and data downloaded from other computer systems 124 via the I / F (interface) 123, and the CPU 111 An area necessary for performing various processes is provided.

  The ROM 113 stores computer function programs and setting data. Reference numeral 114 denotes a display control device, which performs control processing for displaying images, characters, and the like on the display 115. The display 115 displays images and characters. As a display, a CRT, a liquid crystal screen or the like can be applied.

  Reference numeral 116 denotes an operation input device, such as a keyboard or a mouse, which is a device that can input various instructions to the CPU 111. In addition, when inputting various information etc. manually, these can be input via this operation input device 116. FIG. Reference numeral 117 is an I / O for notifying the CPU 111 of various instructions input via the operation input device 116.

  Reference numeral 118 denotes an external storage device that functions as a large-capacity information storage device such as a hard disk, and a program (for example, a tint block image generation program) that causes the CPU 111 to execute an OS (Operating System) and processing according to each of the above embodiments. ), Various types of information, generated copy-forgery-inhibited pattern images, input document images, and the like. Writing information to the external storage device 118 and reading information from the external storage device 118 are performed via the I / O 119.

  Reference numeral 121 denotes a printer for outputting a document or an image. Output data is transmitted from the RAM 112 or the external storage device 118 via the I / O 122 using a network such as a dedicated communication line or LAN, or various transmission forms such as wireless. Sent. Examples of printers for outputting documents and images include ink jet printers, laser beam printers, thermal transfer printers, and dot impact printers.

  Reference numeral 130 denotes a bus connecting the CPU 111, the ROM 113, the RAM 112, the I / O 122, the I / O 119, the display control device 114, the I / F 123, and the I / O 117.

  Here, the processing except the printing unit of the copy-forgery-inhibited pattern image generation unit, which will be described later, is performed by a computer (including at least a portion connected to the bus 130), but a dedicated hardware circuit inside the printer is used. The processing performed by the computer may be executed on the printer side.

  In addition, all of the above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

  The above is the outline of the on-demand printing system.

(Detailed explanation of generation of tint block image)
Next, the tint block image generation process will be described in detail. In the present embodiment, the image corresponding to the background portion of the copy-forgery-inhibited pattern image is designed so that dots are discretely arranged using a dot-dispersed dither matrix, and the latent image reproduced on a copy at the time of copying In the following description, it is assumed that an image corresponding to a portion is designed so that dots are concentrated and arranged using a dot concentration type dither matrix.

  Hereinafter, the dither matrix used to generate the background image is referred to as a background dither matrix, and the dither matrix used to generate the latent image is referred to as a latent image dither matrix.

  The dither method is a method in which a multi-value input image signal is compared with a threshold value calculated according to a certain rule, and a binary image is output based on the magnitude relationship. The dither matrix is a threshold matrix in which thresholds for binarizing an input image signal by the dither method are two-dimensionally arranged.

  A binary image (threshold pattern) is obtained by binarizing the pixel value of the input image signal with the threshold value of the corresponding dither matrix, but the obtained binary image has a tone of the input image signal dithered. If it is less than the threshold value of the matrix, one bit (eg, 1) is assigned to the pixel value, and if it is greater than or equal to the threshold value, the other bit (eg, 0) is assigned.

  In the present embodiment, the binary image constituting the background and the binary image constituting the latent image portion are dark in which the background portion and the latent image portion are substantially the same on human vision when printed on paper using a printer. It is assumed that appropriate input image signals are input so as to be generated in advance by the dither method.

  In the following description, the binary image constituting the background portion is referred to as a background threshold pattern, and the binary image constituting the latent image portion is referred to as a latent image threshold pattern.

  FIG. 2 is a block diagram showing an internal process for generating a tint block image in this embodiment. The copy-forgery-inhibited pattern image generation apparatus includes a copy-forgery-inhibited pattern image generation unit 201, a composition unit 202, a print data processing unit 203, and a print unit 204. In the following description, it is assumed that the printed matter 204 is provided in the printer 121 in FIG.

  First, an input background image, color information, processing region information, latent image threshold pattern, background threshold pattern, latent image background region designation image, and camouflage region designation image are input to the tint block image generation unit 201 to generate a tint block image. Output.

  The tint block image generation unit 201 performs image processing on the input background image according to a predetermined rule, and outputs a tint block image. The input background image is an image corresponding to the generation size of the tint block image, and may be a multi-value image or a binary image. The processing area information indicates an area in the input image information where the background pattern embedding process is performed. This processing area information is expressed by coordinate values or the like, and is determined according to coordinate values determined in advance corresponding to the output paper size or a tint block image application area set by a user interface or the like.

  The latent image background area designation image is a basic image for designating a latent image portion and a background portion, and is composed of one pixel and one bit. One bit value (for example, 1) of the latent image background area designation image represents the latent image portion, and the other bit value (for example, 0) represents the background portion. FIG. 3 is a diagram showing an example of a latent image background area designation image and a camouflage area designation image. Reference numeral 301 is an example of a latent image background area designation image, and reference numeral 302 is an example of a camouflage area designation image. The latent image background area designation image and the camouflage area designation image may be arranged in a tile shape so that the image shown in FIG. 3 corresponds to the print area size.

  The camouflage area designating image is an image for designating an area where the density is to be reduced in order to provide a camouflage effect, and it is assumed that the camouflage area designating image is composed of 1 bit per pixel. One bit value (for example, 1) of the camouflage area designation image indicates that it is not a camouflage area where the density is reduced, and the other bit value (for example, 0) indicates that it is a camouflage area where the density is reduced compared to the surrounding area.

  The tint block image generated by the tint block image generation unit 201 is output to the synthesis unit 202. A method for generating a tint block image will be described in detail later.

  The combining unit 202 combines the input document image and the copy-forgery-inhibited pattern image generated by the copy-forgery-inhibited pattern image generation unit 201 to generate an output document image in which the copy-forgery-inhibited pattern image is combined. Note that, when the copy-forgery-inhibited pattern image is directly used as the copy-forgery-inhibited pattern output original image regardless of the contents of the input document image, it is not necessary to refer to the input document image in the combining unit.

  When a copy-forgery-inhibited pattern output image is generated, color matching processing is executed for each object constituting the copy-forgery-inhibited pattern image or the input original image, and then the object constituting the input original image and the copy-forgery-inhibited pattern image are combined to generate a copy-forgery-inhibited pattern output original image. Alternatively, the print data processing unit 203 in the subsequent stage may execute color matching processing on the copy-forgery-inhibited pattern synthesized output document image.

  In the print data processing unit 203, a drawing interface of an OS (Operating System) (for example, Windows (registered trademark) series Graphic Device Interface (GDI) which is an OS of Microsoft Corporation, MacOS series QuickDraw which is an OS of Apple Computer, etc.) The copy-forgery-inhibited pattern synthesized output original image synthesized by the synthesis unit 202 is received as drawing information and is sequentially converted into a print command. At this time, image processing such as color matching processing, RGB-CMYK conversion, and half-tone processing is executed as necessary. Then, the print data processing unit 203 uses a data format (for example, a data format described in a page description language or a data format developed in a print bitmap) that can be interpreted by the printing unit 204 as the copy-forgery-inhibited pattern output original image data. The data is sent to the subsequent printing unit 204.

  The printing unit 204 prints and outputs a copy-forgery-inhibited pattern composite output document according to the information of the input copy-forgery-inhibited pattern output document image data.

  In the case of a laser beam printer, the printing unit 204 is composed of a printer controller and a printer engine (not shown). The printer controller includes a print information control unit, a page memory, an output control unit, and the like. The print information control unit analyzes the page description language (PDL) sent from the print data processing unit 203, and develops corresponding patterns for drawing and printing commands in the page memory.

  Here, image processing such as RGB-CMYK conversion and half-tone processing is also executed as necessary. If it is determined that the copy-forgery-inhibited pattern output original image data or a part thereof is a print bitmap, the image data is expanded as it is in the page memory.

  The output control unit converts the contents of the page memory into a video signal and outputs it to the printer engine. The printer engine includes, for example, a recording medium transport mechanism, a semiconductor laser unit, a photosensitive drum, a developing unit, a fixing unit, a drum cloning unit, a separation unit, and the like, and performs printing by a known electrophotographic process.

  When the copy-forgery-inhibited pattern image generation unit 201 creates a copy-forgery-inhibited pattern image with the intention that each pixel is printed and output only with the primary colors of the printer (for example, cyan, yellow, magenta, and black), the primary pattern of the printer It is not desirable that each pixel expressed assuming output in colors (cyan, yellow, magenta, black) is printed as a composite color pixel of a plurality of different colors of ink or toner.

  Therefore, in the print data processing unit 203 and the printing unit 204, for pixel values corresponding to the copy-forgery-inhibited pattern image in the copy-forgery-inhibited pattern output original image (for example, cyan, magenta, yellow, and black), It is desirable to set so that a plurality of inks and toners of different colors are not expressed at the same time, that is, not to be a mixed color pixel value. Specifically, it is preferable to introduce a setting in which each pixel is always printed with a single color ink or toner even after color conversion processing such as color matching is passed and halftone processing is executed. However, in the case of an ink jet printer, this is not the case when one pixel of a copy-forgery-inhibited pattern image is expressed by light ink, dark ink, large ink dots, or small ink dots of the same color. Moreover, as a variation of the color of the tint block image, it is possible to generate a tint block image that looks green at first glance by arranging cyan pixels and yellow pixels in a balanced manner. If one pixel is composed of the primary colors of the printer (cyan, yellow, magenta, black), one pixel of the copy-forgery-inhibited pattern image can be accurately output only with the corresponding cyan or yellow toner or ink. desirable.

  However, it is possible to generate an image that realizes the effect of the tint block even if one pixel of the tint block image is not printed out only with the primary colors (cyan, yellow, magenta, black) of the printer. Even if one pixel of a copy-forgery-inhibited pattern image is expressed by a plurality of different colors of ink or toner, it can be used as a forgery-proof copy-forgery-inhibited pattern if a latent image remains after copying (the image appears to float up against the background).

  In this embodiment, the copy-forgery-inhibited pattern image, the input document image, the copy-forgery-inhibited pattern output document image, and the copy-forgery-inhibited pattern output document image data are digital data, and the copy-forgery-inhibited pattern output document image represents an image printed on paper.

  It is also possible to provide the print data processing unit 203 in the preceding stage of the synthesizing unit 202 and execute processing for converting the copy-forgery-inhibited pattern image data generated by the copy-forgery-inhibited pattern image generation unit and input document image data into print commands. In this case, the composition unit 202 is provided in the printer 121 and adopts a configuration in which the copy-forgery-inhibited pattern image data converted into the print command and the input document image data are developed into a bit map image and then combined.

  FIG. 4 is a flowchart showing an internal processing procedure of the tint block image generation unit 201 in the present embodiment. Hereinafter, processing for generating a forgery-inhibited tint block image will be described with reference to FIG. Although this processing is described as being performed by the tint block image generation program, the present invention is not limited to this configuration.

  First, the copy-forgery-inhibited pattern image generation process is started in S401 through an instruction from the user to the user interface or the activation of the program.

  In step S402, the above-described input background image, background threshold pattern, latent image threshold pattern, latent image background area designation image, and camouflage area designation image are read.

  In step S403, an initial pixel for generating a tint block image is determined. For example, when generating a copy-forgery-inhibited pattern image to be applied to the entire printable range of the output paper size of the input image, the data size corresponding to this paper size is the generation size of the copy-forgery-inhibited pattern image. When the copy-forgery-inhibited pattern image is generated by performing image processing in the raster scanning order from the upper left to the lower right for this generation size, the upper left is set as the initial position.

  In step S404, the background threshold pattern, the latent image threshold pattern, the latent image background area designating image, and the camouflage image are arranged on the tile from the upper left of the input background image. Then, the following equation (1) is calculated to determine nWriteDotOn indicating whether or not to write a pixel value corresponding to a dot at the time of printing. At this time, the pixel value corresponds to the input color information.

The definition of the components of the formula is shown below.
nCamouflage: 0 if the pixel is a camouflage area in the camouflage area designation image, 1 otherwise.
nSmallDotOn: 1 if the pixel value is black in the background threshold pattern, 0 if it is white.
nLageDotOn: 1 if the pixel value is black in the latent image threshold pattern, 0 if it is white.
nHiddenMark: 1 for a pixel corresponding to the latent image portion and 0 for a pixel corresponding to the background portion in the latent image background region designation image.

  Note that it is not necessary to calculate using all the elements of Expression (1) for each pixel to be processed. The processing speed can be increased by eliminating unnecessary calculations.

  For example, the above section

  Further, the value of nCamouflage is an integration over the whole. If nCamouflage = 0, nWriteDotOn = 0. Therefore, when nCamouflage = 0, the calculation of equation (2) can be omitted.

  Also, in the generated tint block image, the background threshold pattern, latent image threshold pattern, latent image background area designation image, and camouflage area designation image have the least common multiple of the vertical and horizontal lengths as the minimum unit of repetition. The copy-forgery-inhibited pattern image generation unit 101 generates only a portion of the copy-forgery-inhibited pattern image, which is the minimum unit of repetition, and repeatedly arranges a part of the copy-forgery-inhibited pattern image in a tile shape in the size of the input background image, thereby performing processing related to copy-forgery-inhibited pattern image generation. You can save time.

  Next, in S405, the calculation result (value of nWriteDotOn) in S404 is determined. If nWriteDotOn = 1, the process proceeds to S406. If nWriteDotOn = 0, the process proceeds to S407.

  In S406, a process of writing a pixel value corresponding to a dot at the time of printing is performed.

  The pixel value can be changed according to the color of the tint block image. When it is desired to create a black background pattern, the processing target pixel of the input background image is set to black.

  In addition, a color copy-forgery-inhibited pattern image can be created by setting cyan, magenta, and yellow according to the color of the toner or ink of the printer.

When the input background image is image data of 1 to several bits per pixel, the pixel value may be expressed using the index color. Index color is a method of expressing image data. Color information that frequently appears in a target color image is set in the table of contents (for example, index 0 is white, index 1 is cyan, etc.), and the value of each pixel is color information. It is expressed by the described table of contents numbers (for example, the first pixel value is expressed as index 1 value, the second pixel value is expressed as index 2 value,...).
In S407, it is determined whether all the pixels in the processing target area of the input background image have been processed. If all the pixels in the processing target area of the input background image have not been processed, the process proceeds to 408, an unprocessed pixel is selected, and the processes of S404 to S406 are executed again.

  If the processing for all the pixels in the processing target area of the input background image is completed, the process proceeds to S409, and the image processing in the tint block image generation unit 101 is terminated.

  Through the above processing, a tint block image obtained by performing image processing on the input background image can be generated.

  Next, processing in the composition unit 202 that composes the generated tint block image and an input document image (for example, a form or a certificate) will be described.

  FIG. 5 is a diagram schematically showing the process of combining the input document image and the copy-forgery-inhibited pattern image. 5, reference numeral 501 represents text attribute data, reference numeral 502 represents graphic attribute data, and reference numeral 503 represents an image attribute copy-forgery-inhibited pattern image. Text attribute data 501 and graphic attribute data 502 correspond to an input document image. Of course, the types and formats of input document images are not limited to these types and formats.

  The composition unit 202 superimposes each of the images 501 to 503 by software according to the priority order (layer structure) regarding the arrangement using the OS drawing interface, and the text attribute data and graphic attribute data as indicated by reference numeral 504. An image 504 in which the data and the copy-forgery-inhibited pattern image having the image attribute are combined is generated. This processing is almost the same processing as screen drawing (display drawing) in drawing software which is a general application of a computer. Note that the composition unit 202 may independently perform image composition processing without depending on the drawing interface processing of the OS.

  In FIG. 5, it is assumed that the copy-forgery-inhibited pattern image 503 having the image attribute is superimposed as the lowest layer compared to the text attribute data 501 and the graphic attribute data 502.

  For example, in the position where the image attribute copy-forgery-inhibited pattern image 503 and the text attribute data 501 overlap, the text attribute data 501 is preferentially drawn. Accordingly, the copy-forgery-inhibited pattern image is appropriately arranged in the background of the input document image, and the visibility of the text attribute data and the graphic attribute data is not deteriorated.

  In FIG. 5, the copy-forgery-inhibited pattern image 503 is an image having the same size as the input image. However, when a copy-forgery-inhibited pattern image is to be superimposed only on a part of the area, the copy-forgery-inhibited pattern image generation unit 201 applies the image to the partial area. An input background image having a corresponding size may be input, only a copy-forgery-inhibited pattern image matching the input image size may be generated, and the combining unit 202 may combine it with the input document image.

  The copy-forgery-inhibited pattern combined output document image output by the combining unit 202 may be data expressed by an OS drawing interface, or may be a bitmap image as a result of combining.

  The copy-forgery-inhibited pattern combined output original image generated by the combining unit 202 is sent to the print data processing unit 203 at the subsequent stage.

  The print data processing unit 203 receives the copy-forgery-inhibited pattern synthesized output document image synthesized by the synthesis unit 2102 as drawing information via the OS drawing interface, and sequentially converts it into a print command. At this time, image processing such as color matching processing, RGB-CMYK conversion, and half-tone processing is executed as necessary. Then, the print data processing unit 203 uses a data format (for example, a data format described in a page description language or a data format developed in a print bitmap) that can be interpreted by the printing unit 204 as the copy-forgery-inhibited pattern output original image data. The data is sent to the subsequent printing unit 204.

  The printing unit 204 prints and outputs a copy-forgery-inhibited pattern composite output document according to the information of the input copy-forgery-inhibited pattern output document image data.

  In the above-described method for synthesizing a copy-forgery-inhibited pattern image, the synthesis process for an input document image having a layer structure has been described. Of course, a process for synthesizing a copy-forgery-inhibited pattern image to an input document image having no layer structure is also possible. is there.

(Technical explanation of 2D code expression with multiple camouflage patterns)
Next, a configuration in which a camouflage area designating image capable of expressing digital information, in other words, a camouflage pattern itself has digital information will be described. In this configuration, the camouflage pattern is configured as a matrix of a plurality of patterns (bit expression patterns), and each pattern position is set as arbitrary information, that is, digital information to be embedded, or for camouflaging the information. Whether to use a random value is determined by predetermined key information.

  The information embedded as a camouflage pattern can be extracted not only from the original output output by combining the anti-counterfeiting pattern and the original image, but also from the copy obtained by copying this output. It is also possible to make it possible to extract only from the original, or it is possible to extract everything from the original and extract only a part from the copy. First, a configuration that enables extraction of the same embedded information from an original and a copy will be described.

(First configuration)
First, the structure for expressing arbitrary information with a camouflage pattern is demonstrated using FIG. 6 which showed the 1st structure. This configuration may be provided as a part of the tint block image generation program, or may be provided independently of the tint block image generation program. Although this embodiment will be described as software, it can also be configured as hardware.

  This configuration (functional configuration) includes a redundancy unit 601, a key information generation unit 602, a random number generation unit 603, a key information holding unit 604, and a camouflage configuration unit 605.

  The redundancy unit 601 is a part that performs redundancy of information to be embedded (bit string), and uses repetition or an error correction code for redundancy. For example, it is conceivable to use a known turbo code.

  The random number generation unit 603 generates a random number sequence for randomly arranging a plurality of patterns (bit expression patterns) constituting the camouflage pattern.

  The key information generation unit 602 is a part that generates the above-described key information from the latent image information, the document size information, and the bit expression pattern. In order to make it possible to extract embedded information from the original (output printed with copy-forgery-inhibited pattern image) or a copy, information is embedded only in the latent image portion, and multiple patterns are randomly formed in other portions. (Bit expression pattern) is arranged. For this purpose, the key information in this configuration inputs information for specifying a latent image area which is an area reproduced on a sheet in both the original and the copy. The generated key information is information necessary for extracting arbitrary information expressed by replacing with a camouflage pattern. The latent image information corresponds to a basic image that becomes a copy-forgery-inhibited pattern image, that is, the above-described latent image background region designation image. In this embodiment, since arbitrary information is expressed only in the camouflage pattern portion that is superimposed on the image area configured as the latent image portion, information for identifying the latent image portion and the background portion is required.

  Here, the bit expression pattern refers to a plurality of patterns constituting a camouflage pattern, and each of the plurality of patterns is a pattern representing a different bit string or bit. For example, if 1-bit information is to be expressed, 1 and 0 are allocated to each using two patterns. An example of these two patterns is shown in FIG.

  To represent 2-bit information (bit string), 00, 01, 10, and 11 are appropriately assigned to each of the four patterns. Examples of these four patterns are shown in FIGS. The present invention is not limited to the patterns shown in FIGS. 7, 8, and 9, and any pattern or pattern shape may be used.

Here, the key information is generally a matrix whose elements are 0 or 1, and the size of this matrix is determined as follows.
(Number of lines) = (Width of one page of document) ÷ (Width of bit expression pattern)
(Number of columns) = (Vertical width of one page of document) ÷ (Vertical width of bit expression pattern)
That is, there are as many elements as the number of bit expression patterns included in the background of the document.

  Here, in general, when the element is 1, the corresponding bit expression pattern indicates arbitrary information, that is, digital information to be embedded. When the element is 0, the corresponding bit expression pattern is A random value for camouflaging this digital information indicates a bit expression pattern. In this first configuration, whether an element is 0 or 1 is determined by whether or not a certain bit expression pattern is included in a latent image portion visualized on a copy after copying. . The case of 1 represents a case where all of a certain bit expression pattern is included in the latent image portion, and the case of 0 represents a case where it is not.

  Next, an example of key information is shown using FIG. In FIG. 10, a large cross indicates a latent image, and a lattice indicates a boundary of the bit expression pattern. At this time, the matrix representing the key information is shown superimposed on this figure. FIG. 11 shows combinations of bit expression patterns formed using such key information. FIG. 11 shows an example in which a camouflage pattern is synthesized with a latent image portion and a background portion. As described above, each element has a camouflage pattern defined as either 1 or 0.

  The random number generation unit 603 is a part that generates a random number sequence for determining individual bit expression patterns corresponding to the element 0 of the key information matrix. In order to print a dummy bit expression pattern in the element 0 area, a bit expression pattern corresponding to a randomly assigned number is used as a bit expression pattern corresponding to an element of 0 in the above-described key information matrix. . That is, in this configuration, dummy data is embedded in the camouflage pattern of the background area that disappears after copying, without embedding data to be extracted later. In other words, the camouflage pattern superimposed on the area constituting the background portion in the output is similar to the camouflage pattern superimposed on the latent image portion at first glance, but the information expressed by the camouflage pattern does not make sense. There is no information.

  The key information holding unit 604 is a part that mainly holds key information generated by the key information generation unit 602 from latent image information. The key information may be held in the program, or may be output to another device such as an image reading apparatus.

  The camouflage configuration unit 605 is a part that configures a camouflage area designating image using key information, redundant information, a random number sequence, and a bit expression pattern. Redundant information is embedded using a bit expression pattern corresponding to a part having an element of 1 in a key information matrix, and a random number sequence is embedded using a bit expression pattern corresponding to a part having an element of 0. It will be. In this way, a camouflage area designating image is constructed.

  Then, this camouflage area designating image is input as the camouflage area designating image of FIG. 2 to the above-mentioned tint block image generation unit, and a tint block image in which digital information is embedded can be generated.

  The information on the size of one page of the document is necessary because the size of the output camouflage area designating image is assumed to be equal to the size of one page of the document. Based on this premise, the pattern representing the latent image region can take an arbitrary size.

  As described above, the camouflage region designation image output from the camouflage configuration unit 605 represents not only the role of making the boundary between the latent image portion and the background portion difficult to be seen by human eyes but also digital information. And has a bit expression pattern as shown in FIGS.

  Here, the key information is a matrix created by the following processing, and each element represents whether each bit representation pattern is included in the latent image portion for each bit representation pattern. . In this key information, if all are included, 1 is used, and if not, 0 is used as an element.

As described above, the key information is expressed in the form of a matrix. In order to simplify the description, for example, the key information is 000111010, and the bit sequence of the random number sequence is composed of 2 bits each of r ₁ , r ₂ , r ₃ , r ₄ , r ₅ , r ₆ , r ₇ , Assume that r ₈ and r ₉ are set, and a bit string of arbitrary information is set to a, b, c, and d each consisting of 2 bits, and a bit expression pattern is specified as shown in FIG. 8, for example. In this case, finally, a bit string in the form of r ₁ , r ₂ , r ₃ , a, b, c, r ₇ , d, r ₉ is generated by the key information, and the bit expression pattern corresponding to this bit string is in turn. Are lined up. In this case, a bit string in the form of r ₁ , r ₂ , r ₃ , a, b, c, r ₄ , d, r ₅ may be generated. In short, the bit string of arbitrary information is assigned in order only to the place where the element of the key information is 1.

  Next, a procedure when the above processing is executed as software processing, for example, on a computer will be described with reference to the flow of FIG.

  First, in S1201, arbitrary information (data) to be embedded as a camouflage pattern is input. This input is performed by a user or the like through a user interface. Alternatively, a tint block image generation program or another program may be automatically executed. In addition, here, input or selection of latent image information, document size information, bit expression pattern, and the like, which will be described later, may be performed. In step S1202, the input data is made redundant. For the purpose of this redundancy, in addition to the above, arbitrary information, that is, a bit expression pattern based on digital information to be embedded (corresponding to element 1 of the key information matrix) is made random, You may not be aware that the surrounding bit expression pattern represents specific data. For example, if a specific bit expression pattern is continued twice, it is possible to set the next bit expression pattern in the next order.

  In step S1203, a random number sequence is generated. In step S1204, key information generation processing is performed based on latent image information, document size information, and bit expression pattern size information. Thereafter, in step S1205, a plurality of bit expression patterns themselves are input. In step S1206, the camouflage configuration unit 605 outputs a camouflage area designating image based on the redundant information, random number sequence, key information, and bit expression pattern.

  In the first configuration described above, a configuration in which a camouflage pattern expressing arbitrary information is superimposed on the latent image portion is shown in order to make it possible to reliably extract information from a copy. For the purpose of not extracting any information from the copy, it is also possible to superimpose a camouflage pattern expressing any information on the background. In this case, the key information generation unit 602 may determine whether the element is 0 or 1 depending on whether a bit expression pattern is included in the background portion.

  In the above configuration, the key information generation unit uses the latent image information regardless of whether arbitrary information, that is, digital information to be embedded is applied to the latent image portion or the background portion.

(Second configuration)
In the first configuration of the invention, arbitrary information expressed as a camouflage pattern of the tint block image is extracted from the copied material after copying, that is, the paper in which the background image disappears or becomes thin and the latent image is visualized. The processing to do was described. This is realized by having latent image information as one of the key information, and the portion in which the information is embedded is only the latent image portion. This is because the latent image portion is also reproduced in the copy, and the camouflage pattern drawn so as to overlap the latent image portion can be identified in the copy. Conversely, the case where the portion where information is embedded is the background portion is also added.

  In contrast to the first configuration described above, in the second configuration, a configuration will be described in which only the intended information is extracted from the original forgery-inhibited tint block image, that is, a normal output product. In the case of the present embodiment, the configuration for making the information into a camouflage pattern is substantially the same as in the first embodiment described above, but the difference is that the latent image is generated when the first embodiment generates key information. In contrast to the need for information, the present embodiment does not require latent image information in generating key information. In other words, the present configuration is intended for an image that can be handled in the same manner without providing a latent image portion or without dividing the latent image portion and the background portion. This configuration is shown in FIG. The generation procedure and the processing contents in each processing unit are basically the same as those in the first embodiment.

  If we consider only the extraction of arbitrary information from the original output, which is the synthesized output of the forgery-inhibited tint block and the content image, that is, the camouflage superimposed on the background portion as well as the latent image portion. Information can be expressed even with patterns.

  In the configuration shown in FIG. 13, a part different from the configuration shown in FIG. 6 is a key information generation unit 1302. Although not shown in the figure, it is understood that information for determining whether the element in the key information matrix is 1 or 0 is required. In the first configuration, this is performed based on latent image information. In this configuration, it is also possible to use the element 1 within the predetermined area, or detect the blank area of the input document image shown in FIG. . In particular, when the element 1 portion is a blank area of the input document image, only the camouflage pattern that does not include characters, graphs, symbols, etc. of the input document image is read regardless of the size of the camouflage pattern. Therefore, it is possible to make the data obtained as a result accurate. Of course, even if the camouflage pattern is overwritten by characters, graphs, symbols, etc. of the input document image, the camouflage pattern is not affected by the size or position of the overwritten character etc. It is also possible to consider the size of the line (for example, utilization between lines).

Hereinafter, various generations of key information will be described from the aspect of obtaining data embedded as a camouflage pattern.
1) Only the latent image portion is element 1; data can be obtained from the original and its copy. However, it is affected by the input document image printed thereon.
2) Only the background part is element 1; data can be acquired only from the original. However, it is affected by the input document image printed thereon.
3) All or part of the blank area of the input document image is set as element 1 without using latent image information; data can be acquired only from the original. It is not affected by the input document image printed thereon. When the blank area is small, the amount of data that can be embedded is reduced.

[Other Embodiments]
The first embodiment and the second embodiment of the present invention described above may be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but only one device. The present invention may be applied to an apparatus (for example, a copying machine, a facsimile machine, etc.) comprising

  In addition, an object of the present invention is to supply a recording medium (or storage medium) that records a program code of software that realizes the functions of the above-described embodiments to a system or apparatus, and a computer (or CPU) of the system or apparatus. Needless to say, this can also be achieved by reading and executing the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present embodiment. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. Needless to say, a case where the functions of the above-described embodiments are realized by performing part or all of the actual processing and the processing is included.

  Furthermore, after the program code read from the recording medium is written to a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. It goes without saying that the CPU of the function expansion card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  When the present embodiment is applied to the recording medium, the recording medium stores program codes corresponding to the flowcharts and functional configurations described above.

It is the figure which showed the example of an outline | summary of the on-demand tint block printing system for implement | achieving this invention. It is a block diagram which shows the internal process of a tint block image generation. It is a figure which shows the example of a latent image background area | region designation | designated image and a camouflage area | region designation | designated image. It is the flowchart which showed the procedure of the tint block image generation process. FIG. 6 is a diagram schematically illustrating a composition process of an input document image and a tint block image. It is a block diagram which shows the structure of the camouflage area designation | designated image generation part concerning the 1st Embodiment of this invention. It is a figure which shows an example of a bit expression pattern. It is a figure which shows an example of a bit expression pattern. It is a figure which shows an example of a bit expression pattern. It is a figure which shows an example of key information. It is a figure which shows the example of the tint block image to which the camouflage pattern produced | generated is applied. It is the flowchart which showed the procedure of the camouflage area designation | designated image generation process concerning the 1st Embodiment of this invention. It is a block diagram which shows the structure of the camouflage area designation | designated image generation part concerning the 2nd Embodiment of this invention.

Explanation of symbols

111 CPU
112 RAM
113 ROM
114 Display control device 115 Display 116 Operation input device 117 I / O
118 External storage device 119 I / O
121 Printer 122 I / O
123 Interface 124 Other computer system 201 Copy-forgery-inhibited pattern image generation unit 202 Composition unit 203 Print data processing unit 204 Printing unit 301 Example of latent image background area designation image 302 Example of camouflage area designation image 501 Text attribute data 502 Graphic attribute data 503 Image attribute copy-forgery-inhibited pattern image 504 Image attribute data, graphic attribute data, and image attribute combined copy-forgery-inhibited pattern image 601 Redundancy unit 602 Key information generation unit 603 Random number generation unit 604 Key information holding unit 605 Camouflage configuration unit 701, 702 Pattern examples 801 to 804, 901 to 904 each representing a value of 1 bit 1301 Redundancy unit 1302 Key information generation unit 1303 Random number generation unit 1304 Key information storage Part 1305 camouflage component

Claims (9)

Generating means for generating a tint block image with a white pattern by arranging a plurality of types of white patterns indicating information according to shapes based on information to be embedded (bit string);
Synthesis means for synthesizing the background pattern image with the white pattern generated by the generation means with the input image;
The white pattern is a pattern for making the outline of the latent image included in the tint block image inconspicuous,
The generating means forms the shape of each white pattern included in the plurality of white patterns so as to be based on the bit corresponding to the white pattern in the information (bit string) to be embedded ,
The white pattern is arranged on a specific area based on the information to be embedded (bit string),
The specific area is a latent image area in the tint block image,
The generating means arranges the plurality of types of white patterns in a latent image area based on the information to be embedded ,
The image processing apparatus is characterized in that the generation unit further arranges the plurality of types of white patterns in a background region in a tint block image. The image processing apparatus according to claim 1 , wherein the generation unit arranges the plurality of types of white patterns in a background area based on the generated random number. The generating means includes
Camouflage area designation image generating means for generating a camouflage area designation image by arranging a plurality of types of white patterns indicating information according to the shape on a specific area based on information to be embedded;
A tint block for generating a tint block image with a white pattern based on the camouflage region designation image generated by the camouflage region designation image generating unit, the binary pattern for the latent image portion, and the binary pattern for the background portion. The image processing apparatus according to claim 1, further comprising: an image generation unit.   2. The information processing apparatus according to claim 1, further comprising input means for inputting arbitrary information, wherein the information to be embedded is information generated by making the information input by the input means redundant. The image processing apparatus described. A generation step of generating a tint block image with a white pattern by arranging a plurality of types of white patterns indicating information according to shapes based on information to be embedded (bit string);
A synthesis step of synthesizing the background pattern image with a white pattern generated in the generation step with an input image;
The white pattern is a pattern for making the outline of the latent image included in the tint block image inconspicuous,
The generating step forms the shape of each white pattern included in the plurality of white patterns so as to be based on the bit corresponding to the white pattern in the information to be embedded (bit string) ,
The white pattern is arranged on a specific area based on the information to be embedded (bit string),
The specific area is a latent image area in the tint block image,
The generating step arranges the plurality of types of white patterns in a latent image region based on the information to be embedded ,
The generating step further includes arranging the plurality of types of white patterns in a background area in a tint block image. 6. The method according to claim 5 , wherein the generating step arranges the plurality of types of white patterns in a background region based on the generated random number. The generating step includes
A camouflage area designating image generating step for generating a camouflage area designating image by arranging a plurality of types of white patterns indicating information according to the shape on a specific area based on information to be embedded;
A tint block for generating a tint block image with a white pattern based on the camouflage region designation image generated by the camouflage region designation image generating unit, the binary pattern for the latent image portion, and the binary pattern for the background portion. An image generation process according to claim 5 , further comprising: an image generation step. 6. The method according to claim 5 , further comprising an input step of inputting arbitrary information, wherein the information to be embedded is information generated by making the information input in the input step redundant. A control method of the image processing apparatus described. Computer program for executing the control method according to any one of claims 5 to 8 on a computer.

Images