JP2007166225A - Image-forming device and authentication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image-forming device that maintains secrecy and at the same time can shorten the time of authentication work for improving productivity in reproduction. <P>SOLUTION: The image-forming device has a scanner part 11 and a control unit 16. The scanner part 11 stores identification information inputted by an operator in an internal memory in the control unit 16, and reads an original image where user restriction information is buried for each page. The control unit 16 compares the identification information stored in the memory with the user restriction information of each page for determining whether the operator has authority, and controls the formation of an image according to the determined result. In this case, authentication of each page is performed automatically when the identification information of the operator is inputted first, thus shortening the time required for authentication. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for preventing unauthorized copying of a document image.

  In recent years, copying of documents has become extremely simple due to the widespread use of image forming apparatuses having a copying function, such as personal computers, printers, and copying machines. In such a situation, a manuscript to which copyright has been granted, or a manuscript that prohibits unauthorized duplication such as “copy prohibited”, “restrict copying”, “confidential”, etc. (hereinafter collectively referred to as “confidential manuscript”) There is a drawback that copying is easily performed. In other words, it is a manuscript image containing character strings, figures, tables, graphs, etc., and it is necessary to prevent leakage of important information. The leakage of important information (confidential content) has become a problem. Therefore, it is necessary for an image forming apparatus having a copying function to have a function to prevent misuse and duplication of confidential documents.

  For example, in Patent Document 1, copying prohibition information (whether copying is prohibited), copying permission condition information (information for permitting copying when the conditions are met), latent image information (a latent image that floats when copied) In this technology, additional information such as information) is recorded as a background copy-forgery-inhibited pattern pattern of image data, and a user who can copy is restricted.

  Further, in Patent Document 2, when copying a document, prior to copying, additional information embedded in the document is read and analyzed, and if user restrictions are set by the additional information, user authentication is performed. Techniques for performing are disclosed.

JP 2003-280469 A JP 2004-072343 A

  However, when copying a document with user restriction information added, it is necessary to perform authentication for each page of the read document. For example, when a plurality of originals are read using ADF (Auto Document Feeder), authentication must be performed by analyzing user restriction information embedded every time one page of original is read.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming apparatus and an authentication method that improve the productivity of copying by reducing the time required for authentication work while maintaining confidentiality. And

In order to achieve such an object, an image forming apparatus of the present invention includes a storage unit that stores identification information input by an operator, a reading unit that reads a document image in which user restriction information is embedded for each page, and A control unit that compares the identification information stored in the storage unit with the user restriction information of each page to determine whether or not the user is an authorized operator, and controls image formation according to the determination result; It has and is constituted.
As described above, according to the present invention, if the operator's identification information is input first, authentication of each page is automatically performed, so that the time required for authentication can be shortened.

  In the image forming apparatus, when the control unit determines that the operator is an authorized operator, the control unit forms and outputs an image. When the control unit determines that the operator is an unauthorized operator, the control unit stops the image formation. Good.

  The authentication method of the present invention includes a step of inputting operator identification information, a step of reading a document image in which user restriction information is embedded for each page, the input identification information, and user restriction information of each page. And determining whether or not the operator is an authorized operator, and controlling the image formation according to the determination result.

  The authentication method of the present invention includes a step of reading a document image in which user restriction information is embedded for each page, a step of inputting operator identification information, the input identification information, and user restriction information of each page. And determining whether or not the operator is an authorized operator, and controlling the image formation according to the determination result.

  In the authentication method, the step of controlling the image formation determines that the operator is an authorized operator, forms and outputs an image, and determines that the operator is not authorized, the image formation is performed. It may be a step to stop.

  The present invention can improve the productivity of copying by reducing the time required for the authentication work while maintaining confidentiality.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the image forming apparatus 1 of the present embodiment will be described with reference to FIG. An image forming apparatus 1 according to the present embodiment illustrated in FIG. 1 includes an image developing unit 10, a scanner unit 11, a scanned image processing unit 12, an image storage unit 13, and a copy prohibition information detection unit as an additional information detection device 100. 14, a copy permission condition information detection unit 15, a control unit 16, a background copy-forgery-inhibited pattern image generation unit 17, an image composition unit 18, a print unit 19, and a user interface unit 20.

  The image development unit 10 inputs print data described in a print description language (PDL) via a network such as a LAN. The image expansion unit 10 performs image data expansion processing to generate image data. The generated image data is output to and stored in the image storage unit 13.

  The scanner unit 11 reads a document placed on the platen glass, and outputs the read image data to the scan image processing unit 12.

  The scanned image processing unit 12 performs color correction, color space conversion, screen processing, and the like on the input image data, and stores the image data after the image processing in the image storage unit 13.

  The image composition unit 18 reads the image data from the image storage unit 13 and outputs it to the printing unit 19. In addition, when the control unit 16 is set to synthesize a background pattern image, the background pattern image data stored in the memory in the image composition unit 18 in synchronization with the reading of the image data from the image storage unit 13. , The logical sum (OR) composition is performed on a predetermined color plane of the image data, and the composite image data is output to the print unit 19. The print unit 19 records the combined image data or image data output from the image combining unit 18 on a sheet.

The image forming apparatus according to the present exemplary embodiment is configured to read the additional information embedded in the background copy-forgery-inhibited image from the confidential document in which the background copy-forgery-inhibited pattern image is embedded, and to print the confidential document only to authorized users. .
Additional information embedded in the background pattern image includes the following.
(A) Copy prohibition information (whether or not to prohibit copying)
(B) ... Copy permission condition information (information for permitting copying if the conditions are met)
For example, a personal identification number, a user ID number that permits copying (employee number, etc.), a date and time for canceling copy prohibition, a machine number of a copier that permits copying (C) ... latent image information (related to a latent image that floats when copied) information)
For example, latent image character string, font type, font size, latent image character string direction (angle), background tint image color

  Here, the background copy-forgery-inhibited pattern image will be described in detail with reference to FIG. The background copy-forgery-inhibited pattern image includes a latent image IP and a background pattern PB that covers the entire surface of the output image O.

  The background pattern PB and the latent image IP are different from each other. However, the output image O is formed with a pattern having the same pixel area and pixel color per unit area so that it can be seen by the human eye as a uniform gray background.

  The latent image IP is composed of finer dots than other portions so that the image appears to the extent that the latent image IP can be identified by human eyes in the copied document.

  The background pattern PB is composed of codes. The code is composed of a condition code CD representing arbitrary code data and a prohibited copy code CP that restricts copying.

  The code is composed of a hatched pattern PS representing arbitrary code data. In the oblique line pattern PS, the one represented by a half line inclined 45 degrees counterclockwise with respect to the scanning direction D represents bit 0 of the code data, and the one inclined 135 degrees represents bit 1 of the code data.

  The forbidden copy code CP is composed of a pattern in which the entire hatched pattern PS represents bit 0 and a bit 1. The forbidden copy code CP is used to determine that a copy is restricted when two or more types of forbidden copy codes CP are detected.

The condition code CD is composed of a synchronization code area AS and a data code area AC.
The synchronous code area AS is a code area in which the outer periphery of a rectangular area of a predetermined size surrounding the data code area AC is composed of a hatched pattern PS1 in which all bits 1 are represented.
In the data code area, a code number, a user ID number permitting copying (employee number, etc.), a date and time for canceling copying prohibition, a machine number of a copying machine permitting copying, etc. are encoded and embedded as a condition code CD. ing.

Next, the copy prohibition information detection unit 14 will be described with reference to FIG. FIG. 3 shows a detailed configuration of the copy prohibition information detection unit 14.
The image data output from the scanner unit 11 is input to the gray scale conversion unit 21 and converted from full color to gray scale. Thereafter, it is binarized by the binarization processing unit 22.

  The binarized image data is input to the noise removal processing unit 23, and noise removal processing is performed. Specifically, a pixel block in which black pixels are connected is obtained, and each pixel of the pixel block whose size (number of connected pixels) is not within a predetermined range is replaced with a white pixel. The predetermined range is set to an appropriate range so that the hatched pattern is not deleted, and other patterns (isolated dot patterns, characters and figures in the document, etc.) are deleted.

  The image data from which noise has been removed is input to the pattern detection unit 24, where two types of oblique line pattern detection processing are performed, and the result is output as image data of 2 bits per pixel. Specifically, the pattern shown in FIGS. 4A and 4B is applied at the position of each pixel in the image data, and detection is performed by template matching. Here, when the pattern (A) shown in FIG. 4 is detected, the pixel value 0 is output, and when the pattern (B) shown in FIG. 4 is detected, the pixel value 1 is output and the pattern is not detected. , Pixel value 2 is output.

  The image data output from the pattern detection processing unit 24 is input to the blocking processing unit 25. Here, the block size is set to a size smaller than half the size of the copy prohibition code and the condition code, and is set to a size such that one or more blocks are completely included in the code. The blocking processing unit 25 divides the input image data into blocks of a predetermined size and outputs them to the number calculation unit 26.

  The number calculation unit 26 calculates the number of pixels having a pixel value 0 and the pixel having a pixel value 1 in the block, and outputs the result to the ratio calculation unit 27. The total is output to the determination processing unit 28. The ratio calculation unit 27 calculates the ratio of pixels with a pixel value of 0 and outputs the result to the determination processing unit 28.

  The determination processing unit 28 performs determination processing based on the total number input from the number calculation unit 26 and the ratio input from the ratio calculation unit 27.

  Here, when the inside of the block being processed is located inside the copy prohibition code of all bits 0, a diagonal line pattern corresponding to a predetermined number of bits 0 or more is detected in the block, and bit 1 Since the hatched pattern corresponding to is hardly detected, the ratio of the hatched pattern corresponding to bit 0 should be high and almost close to 1.0.

  If the block currently being processed is located inside the copy prohibition code of all bits 1, a hatched pattern corresponding to a predetermined number of bits 1 or more is detected in the block, and bit 0 is set. Since the corresponding diagonal pattern is hardly detected, the ratio of the diagonal pattern corresponding to bit 0 should be low and almost close to 0.0.

  If the block currently being processed includes at least a part of the condition code, a diagonal line pattern corresponding to a plurality of bits 0 and a diagonal line pattern corresponding to a plurality of bits 1 are detected in the block. The ratio of the hatched pattern corresponding to 1 should be much lower than 1.0 and much higher than 0.

  If the input image data is an image in which copy prohibition information is embedded, a copy prohibition code with all bits 0 in the block and a copy prohibition code with all bits 1 in the block are included in the image. There should be more than one embedded.

The following determination process is performed using the above characteristics.
If the total number> the first threshold value and the ratio> the second threshold value, the block is determined to be the copy prohibition code 0.
Total number> first threshold value and. When (1−ratio)> second threshold value, the block is determined to be copy prohibition code 1.
In cases other than the above, it is determined that the block is not a copy prohibition code. Also, the first threshold value is set by adding a margin to the number of theoretical patterns included in the block from the block size and pattern size. The second threshold value is set to a value close to 1.0.

  The determination processing unit 28 separately counts the number of blocks determined to be the copy prohibition code 0 and the number of blocks determined to be the copy prohibition code 1. If the number of blocks determined to be copy prohibition code 0 is equal to or greater than threshold value 3 and the number of blocks determined to be copy prohibition code 0 is equal to or greater than threshold value 3, the image is determined to be a copy prohibition document; The determination result is output to the control unit 16.

Next, details of the copy permission condition information detection unit 15 will be described with reference to FIG.
The image data output from the scanner unit 11 is input to the gray scale conversion unit 31, converted from full color to gray scale, and then binarized by the binarization processing unit 32.

  The binarized image data is input to the noise removal processing unit 33, and the noise removal processing 33 is performed. The image data from which the noise has been removed is input to the pattern detection processing unit 34, where two types of oblique line pattern detection processing are performed, and the data of the processing result is stored in the buffer memory 35. In this image data, the pixel value at the position where the diagonal line pattern corresponding to bit 0 is detected is 0, the pixel value at the position where the diagonal line pattern corresponding to bit 1 is detected is 1, and other values are 2 The image data is 2 bits per pixel.

  The image data stored in the buffer memory 35 is input to the skew angle detection processing unit 36, and the skew angle is detected. Here, the skew angle of the input image data is obtained. As a specific method, Hough transform is performed on a pixel having only a pixel value of 0 or 1, and the peak of the projection distribution on the angle axis is obtained. The obtained skew angle is output to the code detector 37.

  Further, the image data stored in the buffer memory 35 is read out and input to the code detection unit 37, and the two-dimensional code is detected. Specifically, the image is scanned at the obtained skew angle to extract a pixel value of 0 or 1 (corresponding to 0 or 1 of the bit). The synchronization code is found from the extracted bit string. The synchronization code is defined as a code in which the outer periphery of a rectangular area having a predetermined vertical and horizontal size is entirely composed of bits 1. A bit array surrounded by the synchronization code is a two-dimensional code (condition code). This bit array is rearranged into a one-dimensional bit string and output to the error correction decoding unit 38.

  The error correction decoding unit 38 performs a predetermined error correction decoding process on the input bit string and decodes it as condition information. The decrypted copy permission condition information is output to the control unit 16.

Next, the background pattern image generation unit 17 will be described with reference to FIG.
. Additional information (copy prohibition information, condition information, latent image information) is input from the control unit 16 to the background tint block image generation unit 17. Of these, copy prohibition information and copy permission condition information are input to the additional information encoding unit 42, and latent image information is input to the latent image generation unit 41.

  The latent image generation unit 41 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 direction of the latent image character string (angle) ) Etc. Upon receiving the latent image information, the latent image generation unit 41 draws a latent image character string in the specified direction with the specified font type and font size, and generates a binary latent image image. The generated latent image is output to the additional information encoding unit 42. Note that 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 additional information encoding unit 42 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 image forming apparatus, two types of copy prohibition codes shown in FIGS. 7A and 7B are generated. Here, the copy prohibition code of FIG. 7A is all bit 0 inside the code, and the copy prohibition code of 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 the image forming apparatus, two types of codes shown in FIGS. 7A and 7B are generated. Is not done.

  Next, when condition information is input, an error correction code is applied to the condition information to generate a condition code as shown in FIG. The code in FIG. 7C 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 generated codes are repeatedly arranged as shown in FIG. 8A to generate a pattern number array having the same size as the latent image. Here, the hatched rectangle in the figure is the copy prohibition code in FIG. 7A, the vertical hatched rectangle is the copy prohibition code in FIG. 7B, and the dot hatched rectangle is in FIG. 7C. This is the condition code. If a copy prohibition code is not generated, a condition code is placed in the copy prohibition code portion in the figure. If the condition code is not generated, a copy prohibition code is placed in the condition 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 in which the copy prohibition code and the condition 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”. The pattern number array is output to the pattern image generation unit 44.

  The pattern image generation unit 44 refers to each element of the input pattern number array, reads a pattern corresponding to the pattern number from the pattern storage unit 43 and converts it into a pattern image, thereby generating a background pattern image. The generated background tint block image is stored in a memory (not shown) in the image composition unit 18.

The operation procedure of this embodiment will be described with reference to the flowchart shown in FIG.
When starting the operation, the user inputs identification information such as an assigned user ID and password. The control unit 16 of the image forming apparatus stores the input identification information in a memory (step S1).

  When a document is read from the scanner unit 11, the copy prohibition information detection unit 14 detects copy prohibition information, and the copy permission condition information detection unit 15 detects copy permission condition information. Information indicating whether or not copy prohibition information exists in the document and copy permission condition information are stored in a memory in the control unit 16 for each page.

  In parallel with this operation, the control unit 16 authenticates the authentication information stored in the memory and the detected copy prohibition information and copy permission condition information. If the copy prohibition information cannot be detected by the copy prohibition information detection unit 14 (step S3 / NO), the control unit 16 determines that the copy prohibition original is not permitted and permits the copy of the original (step S9). . If the copy prohibition information can be detected (step S3 / YES), the copy permission condition information is analyzed (step S4). If the copy permission condition information includes condition information for permitting copying (step S5 / YES), authentication is performed by comparison with identification information registered in advance in the memory. If the identification information is included in the condition information for permitting copying, it is determined that there is a copying authority (step S7 / YES), and copying is permitted (step S8). If the identification information is not included in the copy permission condition information, it is determined that there is no copy authority (NO in step S7), and copying is prohibited.

  When the authentication of the copy prohibition information and the permitted copy permission condition information stored in the memory is completed (step S11), and scanning of all originals is completed in the scanner unit 11 (step S12), printing of the original permitted to be copied is performed. To start. Even during scanning of a document, printing may be started as soon as the document authentication is completed.

  Next, a procedure for performing authentication by inputting identification information when all pages of a document or images for a predetermined page are read and permission conditions are set will be described.

  When an original to be read is set on an ADF (not shown) tray and the start button is pressed (step S21 / YES), the ADF conveys the original set on the tray to the scanner unit 11 at a constant speed. To do.

  The scanner unit 11 acquires the image information by reading the document conveyed on the document placing table by the ADF (step S22). This information is subjected to predetermined image processing by the scan image processing unit, and stored in the subsequent image storage unit 13 (step S23).

  The image data read by the scanner unit 11 is input to the copy prohibition information detection unit 14 and the copy permission condition information detection unit 15. The copy prohibition information detection unit 14 detects the copy prohibition information and outputs it to the control unit 16 (step S23). The copy permission condition information detection unit 15 detects the copy permission condition information and outputs it to the control unit 16 (step S23). The control unit 16 stores and manages copy prohibition information and copy permission condition information for each page.

  When the scan of the image data for all pages or arbitrary pages of the document placed on the tray is completed (step S24 / YES), the copy prohibition information is determined from the first page of the document image and the copy permission condition information is authenticated. Do. If copy prohibition information is not set for the first page of the original image (step S25 / NO), copying is permitted (step S26). Here, when copy prohibition information is not set for the image data of the first page, it is determined that copy prohibition information is not set for all pages, but copy prohibition information is set for all pages. It may be determined whether or not.

  If the copy prohibition information is set for the image data of the first page (step S25 / YES), it is determined whether the copy permission condition information is set (step S27), and the copy permission condition information is determined. Is not set (step S27 / NO), it is determined that the document is a copy-prohibited document (step S28), and the copy of the document is prohibited.

  If copy permission condition information is set (step S27 / YES), the control unit analyzes the condition information and extracts authentication information (step S29). The authentication information is information that permits copying of the original, and for example, a group ID or a personal ID is set.

  The control unit 16 that has extracted the authentication information requests the display device of the user interface unit 20 to input identification information (step S30). For example, a message such as “Password is set for this manuscript. Please input the password” is displayed on the display unit to prompt the user to input identification information. If no identification information is input after a predetermined time has elapsed (step S32 / YES), copying of the read original is prohibited (step S33).

  If the identification information is input within a predetermined time (step S31 / YES), the copy permission condition information stored in the memory is sequentially read out, the authentication information is taken out and sequentially compared with the identification information (step S31). S34). When the identification information is not included in the authentication information (NO in step S35), the control unit 16 determines that copying is prohibited and prohibits copying of the document (step S36).

  This authentication process is continuously performed for all copy permission condition information stored in the memory (step S37). When authentication of all copy permission condition information stored in the memory is completed, it is determined whether or not reading of all originals has been completed (step S38). If reading of all originals has not been completed, the processing from step S22 is repeated. When reading of all the originals is completed and it is determined that all the originals have copy authority (step S38 / YES), the control unit 16 permits copying (step S39).

  In this way, in this embodiment, identification information for identifying the user is input and authentication with the copy permission condition information recorded on all pages of the document is performed at one time. Can be improved.

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

1 is a block diagram illustrating a configuration of an image forming apparatus. It is a figure which shows a background tint block image. It is a block diagram which shows the structure of a copy prohibition information detection part. It is a figure which shows an example of the image used for template matching. It is a block diagram which shows the structure of a copy permission condition information detection part. It is a block diagram which shows the structure of a background tint block image generation part. It is a figure which shows copy prohibition information and condition information. It is a figure which shows a pattern number arrangement | sequence. It is a flowchart which shows the operation | movement procedure of 1st Example. It is a flowchart which shows the operation | movement procedure of 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image expansion part 11 Scanner part 12 Scan image processing part 13 Image storage part 14 Copy prohibition information detection part 15 Copy permission condition information detection part 16 Control part 17 Background tint block image generation part 18 Image composition part 19 Print part 20 User interface part

Claims (5)

Storage means for storing identification information input by an operator;
Reading means for reading a manuscript image in which user restriction information is embedded for each page;
Control means for comparing the identification information stored in the storage means with the user restriction information of each page to determine whether or not the user is an authorized operator and to control image formation according to the determination result And an image forming apparatus.   2. The control unit according to claim 1, wherein if the operator is determined to be an authorized operator, an image is formed and output, and if the operator is determined to be an unauthorized operator, the image forming is stopped. The image forming apparatus described. Entering operator identification information;
A step of reading a manuscript image in which user restriction information is embedded for each page;
Comparing the input identification information with the user restriction information of each page to determine whether or not the operator is authorized;
And a step of controlling image formation according to the determination result. A step of reading a manuscript image in which user restriction information is embedded for each page;
Entering operator identification information;
Comparing the input identification information with the user restriction information of each page to determine whether or not the operator has authority;
And a step of controlling image formation according to the determination result. The step of controlling image formation is a step of forming and outputting an image when it is determined that the operator is an authorized operator, and stopping image formation when it is determined that the operator is not authorized. The authentication method according to claim 3 or 4, wherein

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