JP4650250B2 - 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 technique for preventing or suppressing unauthorized copying of confidential documents, when printing confidential documents, the copy prohibition information is embedded in the image and then printed out. 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). ).

  Further, the illegal copy prohibition function has been developed, and two types of copy prohibition information in an image and copy permission condition information (for example, a personal identification number) for permitting copying under a specific condition when a confidential document is printed. Information is embedded and printed out, and at the time of copying, two types of information, copy-prohibited information and copy-permitted condition information, embedded in the image are detected from the scanned image 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. An image processing apparatus that analyzes a user, a client PC, a printer, and a date and time embedded in an image that has been read and read to identify an information leakage source has been studied. This function can be configured as an additional function of the conventional multifunction peripheral.
JP 2003-280469 A JP 2003-283790 A

  However, when embedding different information in units of pages such as page numbers as information to be embedded when a confidential document is printed out, it is necessary to generate a background copy-forgery-inhibited pattern image in which code information is embedded in units of pages and combine it with the document image. Therefore, there is a problem that the processing time for generating the background copy-forgery-inhibited pattern image becomes long and the printing speed is reduced.

  SUMMARY An advantage of some aspects of the invention is that it provides an image processing apparatus and an image processing method capable of embedding code information without reducing printing speed.

To achieve this object, an image processing apparatus according to the present invention generates an image input unit for inputting a document image and a background tint block image to be combined with each page of the document image input by the image input unit. The initial background pattern image to be used, wherein the plurality of blocks obtained by dividing the area of the initial background pattern image into a plurality of blocks having a predetermined size are printed materials in which the printed image of the document image is prohibited from being copied. A block in which a forbidden code indicating the information is arranged, a block in which a fixed information code obtained by encoding fixed information embedded as the same information in each page of the document image, and a page information indicating the page number of the document image are coded. Storage means for storing the initial background tint block image, comprising an arrangement planned block prepared for arranging the converted page information code; An initial background pattern image is read from the storage unit, and a means for generating a background pattern image by arranging the page information code in the arrangement planned block of the read initial background pattern image, A background copy-forgery-inhibited pattern image generation unit that generates a background copy-forgery-inhibited pattern image in which a page information code indicating a page number of a document image to be combined is arranged, and stores the generated background copy-forgery-inhibited pattern image in the storage unit; And an image composition unit for synthesizing the read background tint block image with the document image, and an image output unit for outputting the synthesized image synthesized by the image synthesizing unit, which is arranged in advance on the initial background pattern image The prohibited code is formed of a single pattern of repeated images that can be distinguished from the fixed information code and the page information code. The initial background pattern image is defined such that the prohibition code is arranged between the fixed information code and the page information code so that the fixed information code and the page information code are not adjacent to each other. It is characterized by being.

The present invention generates a background tint block image by arranging a page information code indicating a page number of a document image to be synthesized with a background tint block image on an initial background tint block image prepared in advance. Prohibition codes and fixed information codes are pre-arranged in the initial background pattern image, and it is necessary to re-arrange the prohibition code and fixed information code in the initial background pattern image when generating the background pattern image generated for each page. There is no. For this reason, it is possible to simplify the time and effort required to generate the background copy-forgery-inhibited pattern image and shorten the processing time. Accordingly, it is possible to suppress a decrease in the printing speed of the document image obtained by synthesizing the background copy-forgery-inhibited pattern image.
  In addition, the prohibition code is defined in the initial background pattern image so as to be formed by a single pattern repeated image that can be distinguished from the fixed information code and the page information code. The initial background pattern image includes the fixed information code and the page information code. Since the prohibition code is defined so as to be arranged between the fixed information code and the page information code so that they are not adjacent to each other, the delimitation between the codes becomes clear. Therefore, when a document image combined with a background copy-forgery-inhibited pattern image is formed on a sheet and this image is read by an input device such as a scanner, each code can be accurately identified.

An image processing method according to the present invention is an image processing method executed by an image processing apparatus, wherein a document image is input by an image input unit, and is combined with each page of the document image input by the image input unit. An initial background copy-forgery-inhibited pattern image used to generate a background copy-forgery-inhibited pattern image, wherein the plurality of blocks obtained by dividing the region of the initial background copy-forgery-inhibited pattern image into a plurality of blocks of a predetermined size are copied from the printed material of the document image. A block in which a prohibition code indicating that the print is prohibited, a block in which a fixed information code in which fixed information is embedded as the same information in each page of the document image, and a block of the document image are arranged. A layout plan block prepared for placing a page information code obtained by coding page information indicating a page number. Reading out the initial background pattern image from the storage means storing the background pattern image, and generating the background pattern image by arranging the page information code in the arrangement plan block of the read initial background pattern image. A step of generating a background copy-forgery-inhibited pattern image in which a page information code indicating a page number of a document image to be synthesized with the background copy-forgery-inhibited pattern image is arranged; a step of storing the generated background copy-forgery-inhibited pattern image in the storage unit; Reading the background pattern image, synthesizing the read background pattern image with the document image, and outputting a synthesized image obtained by synthesizing the background pattern image and the document image, the initial stage The prohibition code previously arranged in the background pattern image is a single code that can be distinguished from the fixed information code and the page information code. The initial background pattern image is defined between the fixed information code and the page information code so that the fixed information code and the page information code are not adjacent to each other. It is defined so that prohibited codes are arranged.

  According to the present invention, it is possible to provide an image processing apparatus and an image processing method capable of embedding code information without reducing the printing speed.

  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 multi-function device 1 includes an image developing unit 2 as an image input unit and an information input unit, an image storage unit 3, a reading unit 4, a scanned image processing unit 5, a prohibited code detecting unit 6, a digital code decoding unit. Means 7, user interface means 8, control means 9 as code means, background tint block image generation means 10, image composition means 11, and printing means 12 as 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 background copy-forgery-inhibited pattern 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 scanned image processing unit 5. The scanned image processing unit 5 performs image processing such as image correction, color conversion, and enlargement / reduction on the read image, and stores the image in the image storage unit 3. 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.

  The background copy-forgery-inhibited pattern image generation means 10 generates a background copy-forgery-inhibited pattern image by arranging each code encoded by the control means 9 in a predetermined area of the image. At this time, the background copy-forgery-inhibited pattern image generation means 10 rewrites only the area in which the page information code is arranged in the background copy-forgery-inhibited pattern image for each page of the output document image. That is, for each page of the document image to be output, the background pattern image generation unit 10 rewrites only the area where the page information code is arranged in the background pattern image and generates a plurality of background pattern images corresponding to each page of the document image. And stored in the image storage means 3. The image composition unit 11 synthesizes the document image and the background pattern image generated by the background pattern image generation unit. At this time, the image synthesizing unit 11 reads and synthesizes the document image and the background tint block image of each page accumulated in the image accumulating unit 3. The printing unit 12 prints and records the combined image data synthesized by the image synthesizing unit 11 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. Additional information (copy prohibition information, condition information, latent image information) is input from the control unit 9 to the background tint block image generation unit 10. The background tint block 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 background copy-forgery-inhibited pattern image generation means 10 generates a binary latent image image by drawing a latent image character string in the specified direction with the specified font type and font size.

  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 background copy-forgery-inhibited pattern 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 copy prohibition information is not input or when it does not indicate that a document that has been printed out is not to be copied by a 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 digital code in FIG. 2C represents a bit string of the 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 the figure is the copy prohibition code of FIG. 2A, the vertical hatched rectangle is the copy prohibition code of FIG. 2B, and the dot hatched rectangle is 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 background tint block image generation means 10.

  The background copy-forgery-inhibited pattern 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 copy-forgery-inhibited pattern 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, an operation at the time of printing when generating a background copy-forgery-inhibited pattern image for each page will be described. FIG. 6 is a code layout diagram. The background pattern image generation means 10 finally generates a background pattern image as shown in FIG. As shown in FIG. 6, a copy prohibition code T1 with all bits 0 inside the code and a copy prohibition code T2 with all bits 1 inside the code are arranged every other code. , Job information code B and page information code C are sequentially arranged. Here, the fixed information code A is always the same code even when the job or page is changed, the job information code B is the same code in the same job, and the page information code C is different for each page. FIG. 7 is a diagram of the initial background pattern image stored in the image storage unit 3.

  FIG. 8 is an operation flowchart during printing. In step S11, print data is received via the network and notified to the control means 9. In step S <b> 12, the image development unit 2 generates a document image by decomposing the received print data, and stores the document image in the image storage unit 3. For multiple pages, decompose all pages. In step S 13, the initial background pattern image stored in the image storage unit 3 is read out and input to the background pattern image generation unit 10. Here, as shown in FIG. 7, the initial background tint block image is pre-arranged with bit 0 and bit 1 prohibition codes and fixed information codes, and the area BX and page where the job information code B is to be embedded. No code is stored in the area CX where the information code C is to be embedded.

  In step S14, job information is input from the control means 9 to the background pattern image generation means 10 to generate a background pattern image. In step S15, the background copy-forgery-inhibited pattern image generation unit 10 generates a job code image from the job information, and writes the job code image in the area BX in which the job code of the initial background copy-forgery-inhibited pattern image is arranged. In step S16, the page information of the first page is encoded, and the page code image is written in the area CX in which the page code of the initial background pattern image is arranged. In step S17, the control unit 9 starts image output for the first page. The image composition unit 11 reads the document image of the first page from the image storage unit 3, composes the background pattern image input from the background pattern image generation unit 10, and outputs it to the printing unit 12. In step S18, printing (image formation) is performed on the paper by the printing means 12. In step S19, steps S16 to S19 are repeated for all pages. When all pages are printed, the printing operation is terminated.

  Next, another operation example of the multifunction peripheral according to the embodiment of the present invention will be described. FIG. 9 is another flowchart of the operation of the multifunction machine 1 according to the embodiment of the present invention. Here, an example of generating and accumulating background copy-forgery-inhibited pattern images for all pages and outputting them at once is shown.

  In step S21, print data is received via the network and notified to the control means 9. In step S <b> 22, the image development unit 2 generates a document image by decomposing the received print data, and stores the document image in the image storage unit 3. For multiple pages, decompose all pages. In step S 23, the initial background pattern image stored in the image storage unit 3 is read out and input to the background pattern image generation unit 10. Here, similarly to the above, the prohibition code and the fixed information code are arranged in advance in the initial background pattern image. In step S24, job information is input from the control unit 9 to the background tint block image generation unit 10 to generate a background tint block image.

  In step S25, the background copy-forgery-inhibited pattern image generation means 10 generates a job code image from the job information, and writes the job code image in the area BX (FIG. 7) in which the job code of the initial background copy-forgery-inhibited pattern image is arranged. In step S26, the page information of the first page is encoded, and the page code image is written in the area CX (FIG. 7) in which the page code of the initial background pattern image is arranged to generate the background pattern image of the first page. The image is stored in the image storage unit 3 in association with the document image of the eye. Similarly, background copy-forgery-inhibited pattern images for all pages are generated and stored in the image storage means 3. In step S27, after the background tint block image generation process is completed, the control unit 9 starts image output. The image synthesizing unit 11 reads out the document image and the background copy-forgery-inhibited pattern image in order from the first page from the image storage unit 3, synthesizes them, and outputs them to the printing unit 12. In step S28, the printing unit 12 performs printing (image formation) on the paper. In step S29, steps S27 to S29 are repeated for all pages. When all pages are printed, the printing operation is terminated.

  According to the above embodiment, the information to be embedded is divided into information that switches in units of pages, such as page numbers, and fixed information such as user information, machine identification information, etc., and individual digital codes are generated. To do. Then, the background pattern image is divided into a plurality of code blocks, and it is determined which information code is arranged in each code block. A background copy-forgery-inhibited pattern image including only the fixed information code is generated and stored in advance. At the start of printing, a page unit information code is generated and inserted into the background pattern image. For the second and subsequent pages, only a page unit information code is newly generated, and only that portion is inserted to form a background tint block image for each page. Since it is only necessary to generate a minimum number of images for each page, the processing time can be shortened and a decrease in printing speed can be suppressed.

  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. FIG. It is a figure of the initial background tint block image accumulated in the image accumulation means. 6 is an operation flowchart at the time of printing of the multifunction peripheral according to the embodiment of the present invention. 6 is another operation flowchart of the multi-function peripheral according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multifunction machine 2 Image expansion means 3 Image storage means 4 Reading means 5 Scan image processing means 6 Prohibition code detection means 7 Digital code decoding means 8 User interface means 9 Control means 10 Background tint block image generation means 11 Image composition means 12 Printing means

Claims (2)

An image input means for inputting a document image;
An initial background pattern image used for generating a background pattern image to be combined with each page of the document image input by the image input means, wherein the region of the initial background pattern image is divided into a plurality of blocks of a predetermined size The plurality of blocks include a block in which a prohibition code indicating that the printed matter on which the image of the document image is printed is prohibited from being copied, and fixed information embedded as the same information on each page of the document image. Accumulating the initial background tint block image including a block in which a coded fixed information code is arranged and an arrangement planned block prepared for arranging a page information code in which page information indicating the page number of the document image is coded Storage means to
A means for reading out the initial background pattern image from the storage means, and generating a background pattern image by arranging the page information code in the arrangement planned block of the read initial background pattern image; Generating a background copy-forgery-inhibited pattern image in which a page information code indicating the page number of the document image to be combined is generated, and storing the generated background copy-forgery-inhibited pattern image in the storage unit;
Image composition means for reading out the background pattern image from the storage means and synthesizing the read background pattern image with the document image ;
Image output means for outputting a synthesized image synthesized by the image synthesizing means,
The prohibition code arranged in advance in the initial background pattern image is defined to be formed by a single pattern repeated image that can be distinguished from the fixed information code and the page information code. An image processing apparatus , wherein the prohibition code is defined between the fixed information code and the page information code so that the fixed information code and the page information code are not adjacent to each other. . An image processing method executed by an image processing apparatus,
Inputting a document image by an image input means;
An initial background pattern image used for generating a background pattern image to be combined with each page of the document image input by the image input means, wherein the region of the initial background pattern image is divided into a plurality of blocks of a predetermined size The plurality of blocks include a block in which a prohibition code indicating that the printed matter on which the image of the document image is printed is prohibited from being copied, and fixed information embedded as the same information on each page of the document image. The initial background copy-forgery-inhibited pattern image comprising: a block in which a fixed information code that has been encoded is arranged; and a layout-scheduled block that is prepared for arranging a page information code in which page information indicating the page number of the document image is encoded. The initial background tint block image is read from the stored storage means, and the arrangement planned block of the read initial background tint pattern image is read A step of generating a background comprising the steps of generating a background pattern image, the background pattern image obtained by arranging the page information code indicating the page number of the document image synthesizing the background pattern image by arranging the page information code,
Storing the generated background tint block image in the storage means;
Reading the background copy-forgery-inhibited pattern image from the storage means, and combining the read background copy-forgery-inhibited image with the document image;
Outputting a synthesized image obtained by synthesizing the background tint block image and the document image,
The prohibition code arranged in advance in the initial background pattern image is defined to be formed by a single pattern repeated image that can be distinguished from the fixed information code and the page information code. An image processing method defined so that the prohibition code is arranged between the fixed information code and the page information code so that the fixed information code and the page information code are not adjacent to each other .

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