JP4779628B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to an image processing apparatus and an image processing method capable of preventing information leakage of confidential documents.

  In recent years, with the spread of personal computers, printers, and copying machines, there has been a problem of information leakage due to unauthorized copying of confidential documents printed out. As a conventional technology for preventing and suppressing unauthorized copying of confidential documents, when printing confidential documents, copy prohibition information is embedded in the image and then printed out, and when copying, the original is read and embedded in the image. Multifunction devices having an illegal copy prohibition function are being studied, such as detecting copy prohibition information being detected and stopping normal copy operations when copy prohibition information is included (see, for example, Patent Document 1). ).

  In addition, the unauthorized copying prohibition function has been developed, and when printing confidential documents, there are two types: copy prohibition information in the image, and copy permission condition information (for example, a personal identification number) for permitting copying under specific conditions. Information is embedded and printed out. When copying, two types of information, copy-prohibited information and copy-permitted condition information, embedded in the scanned image are detected to determine whether the copy-permitted condition is met. A multifunction device having an advanced illegal copy prohibition function is also considered, in which the copy operation is stopped when the copy permission condition is not met, but the copy operation is performed when the copy permission condition is met. Here, as an embedding method of copy prohibition information / copy permission condition information, for example, the following method has been proposed (for example, see Patent Document 2).

  That is, a background copy-forgery-inhibited pattern image having a comparatively low density is synthesized with a minute pattern on the entire background of the document image. The background copy-forgery-inhibited pattern image is composed of two regions, a latent image character region and a background region, and each region is composed of different micropatterns. The latent image character area is composed of a relatively small dot pattern, and the background area is composed of an array of two kinds of minute oblique line patterns. The two types of diagonal lines represent bits 0 and 1, respectively, and two-dimensional code images in which the two types of diagonal patterns are two-dimensional arrays of a predetermined size are repeatedly arranged adjacent to each other in the background portion. It has become. The copy permission condition information is embedded in this two-dimensional code.

  As copy prohibition information, the inside of the two-dimensional array is all embedded with a special code configured with a hatched pattern corresponding to bit 0, or the inside of the two-dimensional array is configured with a hatched pattern corresponding to bit 1 all. As another conventional example for preventing unauthorized copying of confidential documents, when printing confidential documents, information related to the user who performed the printing, date / time information, etc. are embedded and printed out, and the printed document is scanned, etc. An image processing apparatus that analyzes the user / client PC / printer / date and time embedded in the read image and identifies the information leakage source has been studied. This function can be configured as an additional function of the conventional multifunction peripheral.

Also, a method has been proposed in which embedded attribute information is separated from an input electronic image, print information is added to the separated attribute information, and the image is embedded and printed again in the separated image (patent). Reference 3).
JP 2003-280469 A JP 2003-283790 A JP 2003-110844 A

  However, with the technology of Patent Document 3, it is possible if the input is an electronic image original, but in the case of a scanned image obtained by reading a paper document or the like with a scanner, it is possible to separate the embedded attribute information from this image. If printing information is added without being separated, both original additional information and additional printing information cannot be detected, and information management for generation of paper documents cannot be performed. It was.

  Accordingly, the present invention has been made in view of the above problems, and an image processing apparatus and an image processing method capable of embedding new information other than embedded information in a document image read from a paper document or the like. The purpose is to provide.

In order to solve the above problems, an image processing apparatus of the present invention includes: a reading means for taking an original image, the obtained document image by said reading means, whether rewritable region capable of rewriting information exists If it is determined that the rewriting area does not exist, the density of the original image obtained by the reading unit is detected, and a non-image area having a density equal to or smaller than a predetermined value and having a predetermined area size is detected. The non-image area is determined as a rewritable area, and a plurality of codes obtained by combining the position information indicating the position of the determined rewritable area and information embedded in the document image included in the document image are repeatedly arranged. and to generate the code image, if it is determined that the rewriting area exists, by coding the rewriting embedded information rewrites the information present in the rewritable area A code image generation means for arranging the over de in the rewritable area in the code image, and superimposing means for generating image data obtained by superimposing said document image and the code image, the image data generated by the superimposing means And an image output means for outputting the image on a sheet. According to the present invention, new information other than embedded information can be embedded in a document image read from a paper document or the like. At this time, since new information can be embedded in the non-image area of the document image, the new information does not overlap the document image.

The image processing method of the present invention is a method of processing an image executed by the image processing apparatus, comprising the steps of: reading an original image, the obtained document image in the step of reading the, rewriting area rewritable information If it is determined whether or not the rewriting area is present, the density of the original image obtained by the reading unit is detected, the density is equal to or less than a predetermined value, and has a predetermined area size. A non-image area is detected, the non-image area is determined as a rewritable area, and position information indicating the position of the determined rewritable area and information embedded in the document image included in the document image are synthesized and coded. generating a plurality repeatedly arranged to code image code, when it is determined that the rewriting area exists, rewrite for rewriting the information present in the rewritable area Steps and, a step of generating an image data obtained by superimposing said document image and the code image, the image generated by the step of placing a code obtained by coding the order included information to the rewrite area in the code image And outputting a data image on a sheet. According to the present invention, new information can be embedded in a document image read from a paper document or the like. At this time, since new information can be embedded in the non-image area of the document image, the new information does not overlap the document image.

  The rewritable area is a non-image portion of the document image. According to the present invention, since new information can be embedded in the non-image part of the document image, the new information does not overlap the document image. The information embedded in the document image includes position information of the rewritable area. According to the present invention, a rewritable area can be easily known.

  An image processing apparatus according to the present invention includes a reading step of reading an image in which information is embedded, and a code image generation step of generating a code image by arranging a code obtained by encoding information embedded in the document image in a predetermined region of the image An image synthesis step for synthesizing the document image and the code image, and an image output step for outputting a synthesized image synthesized by the image synthesis means. The code image generation step is read in the reading step. A code obtained by encoding information to be rewritten when information indicating that the information rewriting area is included in the information embedded in the image is included in the rewriting area. According to the present invention, new information can be embedded in the designated rewritable area.

  Hereinafter, the best mode for carrying out the present invention will be described. FIG. 1 is a block diagram of a multifunction machine according to an embodiment of the present invention. The multifunction device 1 as an image processing apparatus has a plurality of functions such as a print function, a copy function, and a scan function. The multi-function device 1 is connected to a client PC (personal computer) connected to a network such as a LAN (Local Area Network). As shown in FIG. 1, the multifunction device 1 includes an image expanding unit 2, an image storing unit 3, a reading unit 4, a non-image portion detecting unit 5, a prohibited code detecting unit 6, a digital code decoding unit 7, a user interface unit 8, It has a control means 9, a code image generation means 10, an image mask means 11, an image superimposing means 12 as an image synthesizing means, and a printing means as an image output means.

  The image expansion means 2 performs drawing processing of print data (hereinafter referred to as “PDL data”) described in a print description language (PDL) input via the LAN, generates document image data, and draws the drawing data. The document image data is stored in the image storage means 3. The image storage unit 3 stores the document image and the code image in association with the page number. The reading unit 4 reads a document placed on the platen and outputs the read image data to the image storage unit 3. A document image is input from the image development means 2 or the reading means 4. The non-image part detection unit 5 detects a non-image part from the image read by the reading unit 4 and notifies the control unit 9 of the detection result.

  The prohibition code detection means 6 detects the prohibition code from the image read by the reading means 4. The digital code decoding means 7 decodes the digital code from the image read by the reading means 4. The user interface means 8 has an input / output device such as a touch panel display, and is a part that receives various operations and input of embedded information from the user.

  The control means 9 controls the entire multifunction device 1. The control means 9 encodes the fixed information, job information, and page unit information as a fixed information code, job information code, and page information code, respectively. The fixed information includes a machine identification ID of the MFP, a network address (IP address, MAC address), and the like. The job information includes a job identification ID, a transmission source PC network address, a user ID, an output start date and time, a total number of pages, and the like. The page information includes a page number and the like. The part information is information on some of the copies. Further, the control means 9 includes position information of the rewritable area in the information embedded in the document image.

  The code image generating means 10 generates a code image by arranging a code obtained by encoding information to be embedded in a document image in a predetermined area of the image. The code image generation means 10 provides a rewritable area in the code image. The rewritable area is a non-image portion of the document image detected by the non-image portion detection means 5. In addition, the code image generation unit 10, when information indicating that there is a rewriting area of the information is included in the information embedded in the image read by the reading unit 4, Is placed in the rewrite area in the code image. The image mask means 11 masks a halftone dot area in the document image. The image superimposing means 12 synthesizes the document image and the code image. The printing unit 13 prints and records the composite image data synthesized by the image superimposing unit 12 on a sheet and outputs it.

  Next, background tint block image generation processing will be described. FIG. 2 is a schematic diagram for explaining the code. FIG. 3 is a schematic diagram for explaining the pattern number arrangement. The operation of the code image generation means 10 will be described. Additional information (copy prohibition information, condition information, latent image information) is input to the code image generation unit 10 from the control unit 9. The code image generation means 10 generates a latent image based on the input latent image information. The latent image information is information indicating what kind of latent image character is embedded in the pattern image.Specifically, the latent image character string, font type, font size, and latent image character string direction ( Angle) and other information. The code image generation means 10 draws a latent image character string in the specified direction with the specified font type and font size, and generates a latent image information as a binary latent image image.

  Here, the resolution of the latent image is a resolution obtained by dividing the resolution of the printer by the size of a pattern to be described later. For example, when the printer resolution is 600 dpi and the pattern size is 12 pixels × 12 pixels, the resolution of the latent image is 50 dpi. The code image generation means 10 encodes the input copy prohibition information and condition information.

  First, when the copy prohibition information indicates that the document that has been printed out is not to be copied by the copying machine, two types of copy prohibition codes shown in FIGS. 2A and 2B are generated. Here, the copy prohibition code in FIG. 2 (A) has a bit 0 in the entire code, and the copy prohibition code in FIG. is there. When the copy prohibition information is not input or does not indicate that the document that has been printed out is not copied by the copying machine, the two types of codes shown in FIGS. 2A and 2B are generated. Not done.

  Next, when condition information is input, an error correction code is applied to the condition information to generate a digital code as shown in FIG. The code in FIG. 2C represents a bit string of encoded condition information by the arrangement of bit 0 and bit 1. The outer periphery of the cord has a special bit pattern for facilitating the positioning of the cord. Next, a plurality of the generated codes are repeatedly arranged as shown in FIG. 3A to generate a pattern number array having the same size as the size of the latent image. Here, the hatched rectangle in FIG. 2 is the copy prohibition code in FIG. 2A, the vertical hatched rectangle is the copy prohibition code in FIG. 2B, and the dot hatched rectangle is in FIG. 2C. It has become a digital code.

  If a copy prohibition code is not generated, a digital code is placed in the copy prohibition code portion in the figure. If a digital code is not generated, a copy prohibition code is placed in the digital code portion in the figure. At this time, the value of each element of the pattern number array is 0 or 1. Next, referring to the latent image, the pattern number of the element of the pattern number array corresponding to the coordinates of the black pixels in the latent image is changed to 2. If this is performed for all the black pixels in the latent image, the pattern number arrangement is such that the latent image characters are drawn with the pattern number 2 on the background where the copy prohibition code and the digital code are arranged side by side. This state is shown in FIG. A black “COPY” portion in the figure indicates a portion in which the pattern array number is changed to “2”. This pattern number array is output to the code image generating means 10.

  The code image generation unit 10 refers to each element of the input pattern number array, reads a pattern corresponding to the pattern number from the pattern storage unit, and converts it into a pattern image, thereby generating a background tint block image. The generated background tint block image is stored in the image storage means 3.

  4A and 4B are schematic diagrams showing examples of patterns stored in the pattern storage unit. FIG. 4A is a pattern corresponding to pattern number 0, FIG. 4B is a pattern corresponding to pattern number 1, and FIG. 4C is a pattern number. 2 is a pattern corresponding to 2. Here, the pattern number array corresponds to the resolution of the image obtained by dividing the printer resolution by the pattern size, and the pattern image generated based on this is generated by replacing one element of the pattern number array with one pattern. Therefore, the generated pattern image matches the resolution of the printer. Also, the pattern image is an image in which the latent image character is converted into an isolated dot pattern by converting it into a hatched pattern corresponding to the bit value of the copy prohibition code and digital code.

  The pattern image generated in this way is stored in the image storage means 3 as a background tint block image, synthesized with the document image data, and printed on paper. FIG. 5 is a schematic diagram illustrating an example of print output and copy output. An example of a printed image is shown in FIG. 5A (for convenience of explanation, the document image shows an example of a pure white image having no image elements). FIG. 5C is an enlarged view of the area surrounded by the rectangle in FIG. FIG. 5B shows a copy output image when FIG. 5A is copied by a copying machine.

  Next, the operation of the multifunction machine 1 according to the embodiment of the present invention will be described. FIG. 6 is a flowchart illustrating a first operation example of the multifunction peripheral according to the embodiment of the present invention. When the user presses the start button (“Y” in step S101), the reading unit 4 scans the document image (step S102). The non-image portion detection unit 5 detects a non-image area in the scan image based on the read image read by the reading unit (step S103). The control unit 9 determines a rewritable area in the code image generated by the code image generation unit 10 based on the detection result of the non-image portion detection unit 5 (step S104). The code image generation means 10 creates an embedded information image (code image) based on the code information from the control means 9 (step S105) and stores it in the image storage means 3. The image superimposing unit 12 superimposes the document image and code image stored in the image storage unit 3 (step S106). Based on the superimposed image superimposed by the image superimposing means 12, the printing means 13 prints on the recording paper (step S107). In this way, new information other than the embedded information can be embedded in the document image read from the paper document or the like.

  Here, the non-image portion detection means 5 performs a binarization process on the read image read by the reading means 4, detects the presence or absence of an image around the target pixel in a predetermined window, performs non-image pixel determination, and If the area of the image pixel is equal to or greater than a predetermined value, a non-image area is detected. Further, the non-image portion detection means 5 detects the image density around the target pixel in a predetermined window from the read image read by the reading means 4, and performs non-image pixel determination when the image density is less than a predetermined value. When the non-image pixel area is equal to or greater than a predetermined value, the non-image area is detected.

  FIG. 7 is a flowchart illustrating a second operation example of the multifunction machine 1 according to the embodiment of the present invention. When the user presses the start button (“Y” in step S201), the document is scanned by the reading unit 4 (step S202). The non-image portion detection unit 5 detects a non-image area of the scan image based on the read image read by the reading unit 4 (step S203). The control unit 9 determines a rewritable area in the code image generated by the code image generation unit 10 based on the detection result of the non-image portion detection unit 5 (step S204). The control means 9 creates position information of the rewritable area (step S205). The control means 9 combines the position information of the rewritable area and the embedded information (step S206). The code image generation means 10 creates a final embedded information image (step S207) and stores it in the image storage means 3. The image superimposing means 12 superimposes the document image and code image stored in the image storage means 3 (step S208). The printing unit 13 prints the image superimposed by the image superimposing unit 12 on the recording paper (step S209).

  FIG. 8 is a flowchart showing a third operation example of the multifunction machine according to the embodiment of the present invention. When the user presses the start button (“Y” in step S301), the reading unit 4 scans the document image (step S302). When the digital code decoding means 7 detects that there is a rewrite area (step S303), the control means 9 extracts rewrite area information and deletes the information in the rewrite area (step S304). The code image generation means 10 creates a rewrite embedded information image (step S305). That is, the code image generation means 10, when information indicating that there is a rewrite area of the information is included in the information embedded in the image read by the reading means 4, is a code obtained by encoding the information to be rewritten Is placed in the rewrite area in the code image.

  The non-image portion detection unit 5 detects a non-image area of the scanned image based on the image read by the reading unit 4 (step S306). The control means 9 determines a rewritable area based on the detection result of the non-image part detection means 5 (step S307). The control means 9 creates position information of the rewritable area (step S308). The control means 9 combines the position information of the rewritable area and the embedded information (step S309). The code image generation means 10 creates a final embedded information image (step S310) and stores it in the image storage means 3. The image superimposing unit 12 superimposes the document image and the code image stored in the image storage unit 3 (step S311). The printing unit 13 prints the image superimposed by the image superimposing unit 12 on the recording paper (step S312). In this way, new information can be embedded in the designated rewritable area.

  Note that the image processing method of the present invention is realized by the multifunction device 1. The multi-function device 1 is realized using, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The image processing method of the present invention can be realized as a program executed by controlling a computer. This program can be provided by being stored and distributed in a magnetic disk, an optical disk, a semiconductor memory, or other recording media, or distributed via a network.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications, within the scope of the gist of the present invention described in the claims, It can be changed.

1 is a block diagram of a multifunction machine according to an embodiment of the present invention. It is a schematic diagram explaining a code | cord | chord. It is a schematic diagram explaining a pattern number arrangement | sequence. It is a schematic diagram which shows the example of a pattern. It is a schematic diagram which shows the example of a print output and a copy output. 5 is a flowchart illustrating a first operation example of the multifunction peripheral according to the embodiment of the present invention. 6 is a flowchart illustrating a second operation example of the multifunction peripheral according to the embodiment of the present invention. 7 is a flowchart illustrating a third operation example of the multifunction machine according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multifunction machine 2 Image expansion | deployment means 3 Image storage means 4 Reading means 5 Non-image part detection means 6 Prohibition code detection means 7 Digital code decoding means 8 User interface means 9 Control means 10 Code image generation means 11 Image mask means 12 Image superposition means 13 Printing means

Claims (2)

Reading means for taking a document image ;
It is determined whether or not a rewrite area where information can be rewritten exists in the original image obtained by the reading means, and if it is determined that the rewrite area does not exist, the original image obtained by the reading means Position information indicating the position of the determined rewritable area by detecting a non-image area having a density equal to or lower than a predetermined value and having a predetermined area size, determining the non-image area as a rewritable area And a code image obtained by repeatedly arranging a plurality of codes encoded by combining the information to be embedded in the document image included in the document image and determining that the rewrite area exists , the code image exists in the rewrite area. Code image generation means for arranging a code obtained by coding rewrite embedded information for rewriting information to be placed in the rewrite area in the code image;
Superimposing means for generating image data in which the document image and the code image are superimposed;
Image output means for outputting an image of the image data generated by the superimposing means on paper;
An image processing apparatus comprising: An image processing method executed by an image processing apparatus,
Scanning the original image ,
It is determined whether or not there is a rewritable area in which information can be rewritten in the original image obtained in the reading step. If it is determined that the rewritable area does not exist, the original image obtained by the reading unit is determined. Position information indicating the position of the determined rewritable area by detecting a non-image area having a density equal to or lower than a predetermined value and having a predetermined area size, determining the non-image area as a rewritable area And a code image obtained by repeatedly arranging a plurality of codes encoded by combining the information to be embedded in the document image included in the document image and determining that the rewrite area exists , the code image exists in the rewrite area. Placing a code obtained by coding rewrite embedded information for rewriting information to be rewritten in the rewrite area in the code image ;
Generating image data in which the document image and the code image are superimposed;
Outputting an image of the image data generated by the step on a sheet;
An image processing method characterized by comprising:

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