JP2008244611A - Image processing unit and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing unit capable of recording paper fingerprint information in a non-image area. <P>SOLUTION: Paper fingerprints in a plurality of fixed areas (1401, A, B, C) of a white paper 1405 are read and stored by a scanner part for reading the whole white paper. The non-image areas A, B, C are detected and stored by referring to the stored information and image data 1402, 1403, 1404 in one page. In printing, the paper fingerprints in an area equivalent to a white paper area C are read on a carrying path in a device by another scanner for reading only part of paper in a width direction in the device. The read information is compared with the stored paper fingerprints in the non-image area. When there is the corresponding information, the image data 1402, 1403, 1404 and coding information of the area C are synthesized and printed in the white paper. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and an image processing method that can handle optically detected feature data at a plurality of locations on the surface of an image recording medium.

  Paper fingerprint (hereinafter referred to as a paper fingerprint) information is known as optically detected feature data at a plurality of locations on the surface of an image recording medium.

  There are documents where it is important to guarantee the original with respect to official documents such as resident cards, insurance certificates, or other confidential documents. Improving printing technology has led to the printing of paper documents as described above with image forming devices such as printers and copiers. At the same time, counterfeiting using color scanners and color copiers has been implemented. It is becoming necessary to prevent it.

  As a technique for preventing forgery, measures such as embedding a pattern such as a tint block when printing on paper and embossing a pattern when printing are made have been taken. In addition, semiconductor parts such as non-contact ICs and RFIDs may be added to the paper itself, and data for guaranteeing the original may be written and copied on these semiconductor parts. In this case, information read from these semiconductor components by the scanner or copying machine is recorded, and a copy history is recorded. Or in combination with user authentication, copying of information read from a semiconductor component and making it impossible to perform copying with a copying machine unless user authentication is performed are being performed.

  Furthermore, when printing, specific pattern information is embedded as invisible information in a halftone that is invisible to the user, and when copying, the printing operation is stopped when the scanner or copier reads the information. It is happening.

  However, in order to add the semiconductor component or the like to paper, there is a problem that the price of the paper itself increases. In addition, special hardware is required for scanners and copiers in order to add invisible information and support non-contact ICs and RFIDs, resulting in increased costs. Another problem is that the invisible information may be counterfeited by being read by a scanner or a copying machine.

  In response to such a problem, the original paper (printed material) is utilized by utilizing the fact that the arrangement of fibers on the surface of paper, which is an image recording medium, is different for each recording medium such as paper. It is performed to determine whether or not. That is, the surface of a recording medium such as paper is read by a reading unit such as a scanner or a copying machine, and the read fiber arrangement is converted into digital information as pattern data. Record in halftone. Thus, when a recording medium such as paper once printed is read for copying again, the pattern information of the fiber that the paper itself has is compared with the pattern data converted into digital information printed on the paper. As a result, whether or not it is an original is being performed. In this case, it is possible to guarantee the original document at low cost by modifying a part of the software using an existing scanner, printer, or copying machine.

JP 2004-102562 A

  However, the above prior art has the following problems. That is, first, an original document is created by printing a public document such as a resident's card, an insurance certificate, or other confidential documents on a recording medium such as paper with a printer or a copying machine. Before the creation, it is possible to read the characteristic data of the paper in an area where printing will be performed by a printer or copier, for example, by a reading unit such as a scanner of the copier. However, if, for example, solid black is printed in the area after the feature data is read, the feature data of the paper may not be read correctly when reading again to determine whether the printed matter is the original. There was a problem.

  Accordingly, an object of the present invention is to provide an image processing apparatus, an image processing method, a program, and a storage medium that have solved the above problems.

  The present invention refers to first storage means for storing optically detected feature data at a plurality of locations on the surface of an image recording medium, and image data to form an image on the image recording medium. Non-image area detecting means for detecting a non-image area in which data is not recorded on the image recording medium, and the non-image area among feature data at a plurality of locations of the image recording medium stored in the first storage means. Feature data selection means for selecting feature data corresponding to the non-image area detected by the image area detection means, and feature data selected by the feature data selection means are stored as feature data for specifying an image recording medium And a second storage means.

  According to the present invention, feature data optically detected at a plurality of locations on an image recording medium such as paper is stored in advance, and feature data corresponding to a non-image area is detected and stored. This makes it possible to use the feature data of the area determined to be a non-image area. As a result, for example, printing is performed in solid black so that the feature data cannot be read accurately later. It becomes.

  Also, only a part of the feature data in the width direction of the image recording medium is read, the feature data of other areas of the same image recording medium are read in advance and inquired to the storage means, and all the feature data is read. It can be handled. Thereby, the reading means inside the machine body and the processing means for the reading result can be realized with a simple structure.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[Example 1]
<Printing system (Fig. 1)>
Next, Example 1 will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a printing system according to an embodiment of the present invention. In this system, the host computer 40 and the three image forming apparatuses (10, 20, 30) are connected to the LAN 50. However, in the printing system according to the present invention, the number of connections is not limited. In this embodiment, LAN is applied as a connection method, but the present invention is not limited to this. For example, an arbitrary network such as a WAN (public line), a serial transmission method such as USB, and a parallel transmission method such as Centronics and SCSI can be applied.

  A host computer (hereinafter referred to as a PC) 40 has a function of a personal computer. The PC 40 can send and receive files and send and receive e-mails using the FTP and SMB protocols via the LAN 50 and WAN. Further, it is possible to send a print command from the PC 40 to the image forming apparatuses 10, 20, and 30 via a printer driver.

  The image forming apparatuses 10 and 20 are apparatuses having the same configuration. The image forming apparatus 30 is an image forming apparatus having only a print function, and does not have the scanner unit included in the image forming apparatuses 10 and 20. In the following, for the sake of simplicity of explanation, the configuration will be described in detail focusing on the image forming apparatus 10 of the image forming apparatuses 10 and 20.

  The image forming apparatus 10 includes a scanner unit 13 that is an image input device and a printer unit 14 that is an image output device. The image forming apparatus 10 further includes a controller 11 that controls operation of the entire image forming apparatus 10 and an operation unit 12 that is a user interface (UI).

<Image Forming Apparatus 10 (FIG. 2)>
An appearance of the image forming apparatus 10 is shown in FIG. The scanner unit 13 has a plurality of CCDs. If the sensitivity of each CCD is different, it is recognized that each pixel has a different density even if the density of each pixel on the document is the same. Therefore, the scanner unit first performs exposure scanning on a white plate (uniformly white plate), converts the amount of reflected light obtained by the exposure scanning into an electrical signal, and outputs it to the controller 11. As will be described later, the shading correction unit 500 in the controller 11 recognizes the difference in sensitivity of each CCD based on the electric signal obtained from each CCD. Then, using the recognized difference in sensitivity, the value of the electric signal obtained by scanning the image on the document is corrected. Further, when the shading correction unit 500 receives gain adjustment information from a CPU 301 in the controller 11 described later, the shading correction unit 500 performs gain adjustment according to the information. The gain adjustment information is used to adjust how the electric signal value obtained by exposing and scanning the original is assigned to the luminance signal value of 0 to 255. By this gain adjustment, the value of the electrical signal obtained by exposing and scanning the document can be converted into a high luminance signal value or converted into a low luminance signal value. Next, a configuration for scanning the image on the document will be described.

  The scanner unit 13 converts information of an image into an electrical signal by inputting reflected light obtained by exposing and scanning the image on the document to the CCD. The scanner unit 13 further converts the electrical signal into a luminance signal composed of R, G, and B colors, and outputs the luminance signal to the controller 11 as image data.

  The document is set on the tray 202 of the document feeder 201. When the user instructs to start reading from the operation unit 12, a document reading instruction is given from the controller 11 to the scanner unit 13. Details of the operation unit 12 will be described later. Upon receiving this instruction, the scanner unit 13 feeds the documents one by one from the tray 202 of the document feeder 201 and performs a document reading operation. Note that the document reading method is not an automatic feeding method by the document feeder 201, but a method of scanning the document by placing the document on a glass surface (not shown) and moving the exposure unit.

  The printer unit 14 is an image forming device that forms image data received from the controller 11 on a sheet. In this embodiment, the image forming method is an electrophotographic method using a photosensitive drum or a photosensitive belt, but the present invention is not limited to this. For example, the present invention can also be applied to an ink jet system that prints on paper by ejecting ink from a micro nozzle array. The printer unit 14 is provided with a plurality of paper cassettes 203, 204, and 205 that allow selection of different paper sizes or different paper orientations. The paper after printing is discharged to the paper discharge tray 206.

  FIG. 17 is a cross-sectional view of the printer unit 14 and the scanner unit 13. The printer unit 14 includes a laser exposure unit 1701, an image forming unit 1702, a fixing unit 1703, and a paper feeding / conveying unit 1704. These components are controlled by the controller 11. The laser exposure unit 1701 causes a light beam such as a laser beam modulated according to the image data to enter a rotating polygonal mirror (polygon mirror) that rotates at a constant angular velocity, and irradiates the photosensitive drum 1709 as reflected scanning light.

  The image forming unit 1702 rotates the photosensitive drum 1709 and charges it with a charger, and develops the latent image formed on the photosensitive drum 1709 by the laser exposure unit 1701 with toner. Further, the image forming unit 1702 performs image formation by executing a series of electrophotographic processes in which the toner image is transferred to a sheet, and minute toner remaining on the photosensitive drum 1709 without being transferred at that time is collected. At that time, the sheet is wound around a predetermined position of the transfer drum and rotated four times. That is, during the four rotations, the above-described electrophotographic processes are sequentially repeated with each developing unit (developing station) having magenta (M), cyan (C), yellow (Y), and black (K) toners being replaced. Execute. The developing units are indicated by 1730, 1731, 1732 and 1733 in FIG. After four rotations, the sheet on which the four color full-color toner images have been transferred leaves the transfer drum and is conveyed to the fixing unit 1703. The fixing unit 1703 includes a combination of a roller and a belt, and includes a heat source such as a halogen heater. The toner on the sheet onto which the toner image has been transferred by the image forming unit 1702 is melted and fixed by heat and pressure. The sheet feeding / conveying unit 1704 has one or more sheet storages represented by a sheet cassette or a paper deck, and one sheet is selected from a plurality of sheets stored in the sheet storage according to an instruction from the controller 11. Separated and conveyed to the image forming unit 1702 and the fixing unit 1703. The sheet is wound around the transfer drum 1711 of the image forming unit 1702, and after four rotations, the sheet is conveyed to the fixing unit 1703. During the four rotations, the above-described toner images of each color of YMCK are transferred to the sheet. Further, when forming an image on both sides of the sheet, control is performed so that the sheet that has passed through the fixing unit 1703 passes through a conveyance path for conveying the sheet to the image forming unit 1702 again.

  In addition, a paper fingerprint reading sensor constituting an internal scanner unit 1705 for reading a paper fingerprint of the fed paper is provided on the paper transport path 1706 of the printer unit 14. The paper fingerprint reading sensor that constitutes the internal scanner unit 1705 reads the fiber irregularities of the paper that is being fed and supplied to the image forming unit, and converts the read information on the irregular image of the fibers into an electrical signal. Further, the electric signal is converted into a luminance signal composed of R, G, and B colors, and the luminance signal is output to the controller 11 as image data. The output signal is subjected to processing similar to that described later (<processing by the paper fingerprint information acquisition unit 607 in <detailed description of the scanner image processing unit 312 (FIG. 6)>) to acquire paper fingerprint information. That is, the paper fingerprint information constitutes optically detected feature data. The paper fingerprint reading sensor constituting the internal scanner unit 1705 can be moved in a direction orthogonal to the paper transport direction (paper width direction) by the moving means. In this case, a paper fingerprint at a desired position in the width direction of the paper can be read. The moving means can be controlled by a CPU 301 in the controller 11 described later, and instruction information for the control can be performed from the operation unit 12.

<Detailed Description of Controller 11 (FIG. 3)>
FIG. 3 is a block diagram for explaining the configuration of the controller 11 of the image forming apparatus 10 in more detail.

  The controller 11 is electrically connected to the scanner unit 13 and the printer unit 14. On the other hand, the controller 11 is connected to the PC 40 or an external device via the LAN 50 or the WAN 331. As a result, image data and device information can be input and output.

  The CPU 301 comprehensively controls access to various connected devices based on a control program or the like stored in the ROM 303 serving as storage means, and also comprehensively controls various processes performed in the controller. A RAM 302 is a system work memory for the operation of the CPU 301 and also a memory for temporarily storing image data. The RAM 302 includes an SRAM that retains stored content even after the power is turned off, and a DRAM that erases the stored content after the power is turned off. The ROM 303 stores a boot program for the apparatus. An HDD 304 is a hard disk drive and can store system software and image data.

  The operation unit I / F 305 is an interface unit for connecting the system bus 310 and the operation unit 12. The operation unit 12 has an operation display screen on the main body of the image forming apparatus 10. The operation display screen of the operation unit 12 constitutes a sensor capable of touch key input at each of a plurality of predetermined locations. The operation unit I / F 305 receives image data as tab information to be displayed at predetermined positions on the operation display screen of the operation unit 12 from the system bus 310 and outputs the image data to the operation unit 12. The operation unit I / F 305 outputs information input by pressing (touching) the touch sensor at a predetermined position on the operation display screen of the operation unit 12 to the system bus 310.

  FIG. 8 is an initial screen of the operation display screen of the operation unit 12 in the image forming apparatus 10. An area 801 indicates whether or not the image forming apparatus 10 is ready to copy, and indicates the set number of copies. A document selection tab 804 is a tab for selecting a document type, and when this tab is depressed, three types of selection menus of text, photo, and text / photo mode are popped up. A finishing tab 806 is a tab for performing settings related to various finishings. A duplex setting tab 807 is a tab for performing settings relating to duplex reading and duplex printing. A reading mode tab 802 is a tab for selecting an original reading mode. When this tab is depressed, three types of selection menus of color / black / automatic (ACS) are popped up. Note that color copy is performed when color is selected, and monochrome copy is performed when black is selected. When ACS is selected, the copy mode is determined by the monochrome color determination signal described above. An area 808 is a tab for selecting a paper fingerprint information registration process. The paper fingerprint information registration process will be described later. An area 809 is a tab for selecting a paper fingerprint information matching process. This paper fingerprint information matching process will be described later.

  A network I / F 306 is connected to the LAN 50 and the system bus 310 to input / output information. The Modem 307 is connected to the WAN 331 and the system bus 310, and inputs and outputs information. A binary image rotation unit 308 converts the direction of image data before transmission. The binary image compression / decompression unit 309 converts the resolution of the image data before transmission into a resolution that matches a predetermined resolution or the partner's ability. For compression and expansion, methods such as JBIG, MMR, MR, and MH are used. The image bus 330 is a transmission path for exchanging image data, and is configured by a PCI bus or IEEE1394.

  The scanner image processing unit 312 corrects, processes, and edits image data received from the scanner unit 13 via the scanner I / F 311. The scanner image processing unit 312 determines whether the received image data is a color document or a monochrome document, a character document, or a photographic document. Then, the determination result is attached to the image data. Such accompanying information is referred to as attribute data. Furthermore, the attribute data can also output information for determining whether or not the image is in an area, and this attribute data is used when registering paper fingerprint information of a non-image area to be described later. Is done. Details of processing performed by the scanner image processing unit 312 will be described later.

  The compression unit 313 receives the image data from the scanner image processing unit 312 and divides the image data into blocks of 32 pixels × 32 pixels. The 32 × 32 pixel image data is referred to as tile data. FIG. 4 conceptually shows this tile data. In the document (paper medium before reading) 400, an area corresponding to the tile data is referred to as a tile image. The tile data is added with the average luminance information in the 32 × 32 pixel block and the coordinate position of the tile image on the document as header information. Further, the compression unit 313 compresses image data including a plurality of tile data and supplies the compressed image data onto the image bus 330.

  The paper fingerprint reading sensor constituting the internal scanner unit 1705 reads a predetermined fixed area 501 (x and y pixels in the vertical and horizontal directions) of the paper 550 as shown in FIG. It is for capturing paper fingerprints. The scanner I / F 331, the scanner image processing unit 332, and the compression unit 333 have the same functions as the scanner I / F 311, the scanner image processing unit 312, and the compression unit 313. However, these are not for reading the entire paper, but for reading a fixed area as shown in FIG. 5, so that the circuit scale is larger than that of the scanner I / F 311, the scanner image processing unit 312, and the compression unit 313. Is small.

  The decompression unit 316 decompresses image data including a plurality of tile data received via the image bus 330, rasterizes the image data, and sends the raster data to the printer image processing unit 315.

  The printer image processing unit 315 receives the image data sent from the decompression unit 316 and performs image processing on the image data while referring to attribute data attached to the image data. The image data after the image processing is output to the printer unit 14 via the printer I / F 314. Details of processing performed by the printer image processing unit 315 will be described later.

  An image conversion unit 317 connected to the image bus 330 so as to be able to exchange data performs a predetermined conversion process on the image data. This processing unit includes components as indicated by reference numerals 318 to 327 below.

  A decompression unit 318 decompresses received image data. A compression unit 319 compresses the received image data. A rotation unit 320 rotates received image data. The scaling unit 321 performs resolution conversion processing (for example, 600 dpi to 200 dpi) on the received image data. The color space conversion unit 322 converts the color space of the received image data. The color space conversion unit 322 performs a known background removal process using a matrix or a table, performs a known LOG conversion process (RGB → CMY), or performs a known output color correction process (CMY → CMYK). Can be. The binary multi-value conversion unit 323 converts the received two-gradation image data into 256-gradation image data. Conversely, the multi-level binary conversion unit 324 converts the received 256-gradation image data into 2-gradation image data using a technique such as error diffusion processing.

  The synthesizer 327 synthesizes the received two pieces of image data to generate one piece of image data. When combining two pieces of image data, a method of using an average value of luminance values of pixels to be combined as a combined luminance value, or a luminance value of a pixel having a brighter luminance level, A method for obtaining a luminance value is applied. In addition, it is possible to use a method in which the darker pixel is used as a synthesized pixel. Furthermore, a method of determining a luminance value after synthesis by a logical sum operation, a logical product operation, an exclusive logical sum operation, or the like between pixels to be synthesized is also applicable. These synthesis methods are all well-known methods. The thinning unit 326 performs resolution conversion by thinning out the pixels of the received image data, and generates image data such as 1/2, 1/4, and 1/8. The moving unit 325 adds a margin part to the received image data or deletes the margin part. The above is the configuration of the image conversion unit 317.

  The RIP 328 receives intermediate data generated based on PDL code data transmitted from the PC 40 or the like via the system bus 310, and generates bitmap data (multi-value). When generating the bitmap, the RIP 328 can generate the region information of the image with reference to the intermediate data. For example, region information indicating whether the image is JPEG, text, or a non-image region where no image exists is generated separately from the bitmap data. Furthermore, it is possible to register a paper fingerprint in a non-image area by using this area information when registering a paper fingerprint to be described later.

<Detailed Description of Scanner Image Processing Unit 312 (FIG. 6)>
FIG. 6 shows an internal configuration of the scanner image processing unit 312.

  The scanner image processing unit 312 receives image data composed of RGB 8-bit luminance signals.

  The shading correction unit 600 performs shading correction on the luminance signal. As described above, the shading correction is a process for preventing the brightness of the document from being erroneously recognized due to variations in CCD sensitivity. Further, as described above, the shading correction unit 500 can perform gain adjustment according to an instruction from the CPU 301.

  Subsequently, the luminance signal is converted into a standard luminance signal that does not depend on the CCD filter color by the masking processing unit 601.

  The filter processing unit 602 arbitrarily corrects the spatial frequency of the received image data. This processing unit performs arithmetic processing using, for example, a 7 × 7 matrix on the received image data. By the way, in a copying machine or a multifunction machine, a character mode, a photo mode, or a character / photo mode can be selected as a copy mode by pressing a tab 804 in FIG. 8 (details will be described later). If the character mode is selected by the user, the filter processing unit 602602502 applies a character filter to the entire image data. When the photo mode is selected, a photo filter is applied to the entire image data. When the character / photo mode is selected, the filter is adaptively switched for each pixel in accordance with a character photo determination signal (part of attribute data) described later. In other words, it is determined for each pixel whether to apply a photo filter or a character filter. Note that coefficients for smoothing only high-frequency components are set in the photographic filter. This is because the roughness of the image is not noticeable. In addition, a coefficient for performing strong edge enhancement is set in the character filter. This is to increase the sharpness of the characters.

  The histogram generation unit 603 samples the luminance data of each pixel constituting the image data received from the filter processing unit 602. More specifically, luminance data in a rectangular area surrounded by a start point and an end point specified in the main scanning direction and the sub scanning direction are sampled at a constant pitch in the main scanning direction and the sub scanning direction. Then, histogram data is generated based on the sampling result. The generated histogram data is used to estimate the background level when performing background removal processing. The input side gamma correction unit 604 converts the data from the histogram generation unit 603 into luminance data having nonlinear characteristics using a table or the like, and outputs the luminance data to the compression unit 313.

  The color / monochrome determination unit 605 determines whether each pixel constituting the image data received from the masking processing unit 601 is a chromatic color or an achromatic color, and the determination result is a color / monochrome determination signal (part of attribute data). ) As image data.

  The character photo determination unit 606 performs the following processing on the image data received from the masking processing unit 601. That is, whether each pixel constituting the received image data is a pixel constituting a character, a pixel constituting a halftone dot, a pixel constituting a character in a halftone dot, or a pixel constituting a solid image. The determination is made based on the pixel value of each pixel and the pixel values of surrounding pixels of each pixel. It should be noted that a pixel that does not correspond to any one is determined to be a pixel constituting a white area. Then, the determination result is attached to the image data as a character / photo determination signal (part of the attribute data).

  The paper fingerprint information acquisition unit 607 acquires image data of a plurality of predetermined areas among the RGB image data input from the shading correction unit 600. The plurality of areas correspond to, for example, the respective areas (for example, areas A, B, C, and 1401) indicated by the squares in FIG. 14 in the input RGB image data.

  FIG. 9 is a flowchart showing a paper fingerprint information acquisition process performed by the paper fingerprint information acquisition unit 607.

  In step 901, the image data extracted by the paper fingerprint information acquisition unit 607 is converted into grayscale image data. In step 902, mask data for collation is created by removing from the image converted to grayscale image data in step 901 what may cause erroneous determination such as printing or handwritten characters. The mask data is binary data of “0” or “1”. In the grayscale image data, the value of the mask data is set to “1” for a pixel whose luminance signal value is equal to or greater than the first threshold (that is, bright). Further, the mask data value is set to “0” for a pixel whose luminance signal value is less than the first threshold value. The above processing is performed on each pixel included in the grayscale image data. In step 903, the image data converted to gray scale in step 901 and the mask data created in step 902 are acquired as paper fingerprint information. Next, the processing shifts to step 904, and it is determined whether or not the reading of the paper fingerprint information of all the predetermined areas of the entire paper has been completed. If the paper fingerprint information of all the areas has not been read yet, the process returns to step S901 again to read the paper fingerprint information of the remaining areas.

  When the reading of the paper fingerprint information of all the predetermined areas of the entire paper is completed, the paper fingerprint information acquisition unit 607 sends the paper fingerprint information of the predetermined area to the RAM 302 using a data bus (not shown). . The paper fingerprint information temporarily stored in the RAM 302 is transferred to the HDD 304 and stored for each paper.

  When the image data output from the masking processing unit 601 includes code image data including data obtained by encoding paper fingerprint information generated as described later, the decoding unit 608 detects the presence. Then, the detected code image data is decoded to extract information.

<Detailed Description of Printer Image Processing Unit 315 (FIG. 7)>
FIG. 7 shows the flow of processing performed in the printer image processing 315.

  The background removal processing unit 701 uses the histogram generated by the scanner image processing unit 312 to remove (remove) the background color of the image data. The monochrome generation unit 702 converts the color data from the background removal processing unit 701 into monochrome data. The Log conversion unit 703 performs luminance density conversion of the image data from the monochrome generation unit 702. For example, the log conversion unit 703 converts RGB input image data into CMY image data. The output color correction unit 704 corrects the output color of the image data from the log conversion unit 703. For example, image data input as CMY is converted into CMYK image data using a table or matrix. The output-side gamma correction unit 705 corrects the input signal value so that the signal value input from the output color correction unit 704 to the output-side gamma correction unit 705 is proportional to the reflection density value after copy output. The code image synthesis unit 707 synthesizes (original) image data corrected by the output-side gamma correction unit 705 and code image data generated by <paper fingerprint information encoding processing> described later. The halftone correction unit 706 performs halftone processing on the image data from the output-side gamma correction unit 705 or the composite image data from the code image synthesis unit 707 in accordance with the number of gradations of the printer unit to be output. For example, the received high gradation image data is binarized or binarized.

  Each processing unit in the scanner image processing unit 312 or the printer image processing unit 315 can output the received image data without performing each processing. Such passing of data without performing processing in a certain processing unit will be expressed as “through the processing unit” below.

<Paper fingerprint information encoding process>
In the paper fingerprint information encoding process, the CPU 301 reads the paper fingerprint information of a predetermined area of the paper sent from the paper fingerprint information acquisition unit 607 to the RAM 302 and stored in the HDD 304, and encodes the read paper fingerprint information. To generate code image data. That is, the registration information for each paper in the HDD 304 includes gray scale image data, mask data, and code image data.

  In this specification, the code image indicates an image such as a two-dimensional code image or a barcode image.

  Further, the CPU 301 transmits the generated code image data to the code image synthesis unit 707 in the printer image processing unit 315 using a data bus (not shown).

  The above control (code image generation control, transmission control) is performed, for example, by executing a program read from the HDD 304 and stored in the RAM 302.

<Paper fingerprint information matching process>
In the paper fingerprint information matching processing, the CPU 301 performs matching processing between different paper fingerprint information on the RAM 302, calculates the matching degree, and compares the matching degree with the threshold value. Then, “valid” indicating that the two match or “invalid” indicating that they do not match is basically determined. Details will be described later. Specifically, there are two forms of paper fingerprint information matching processing. One is when the paper fingerprint information collation tab is pressed, and the other is when the paper fingerprint information registration processing tab is pressed. These correspond to feature data matching processing instructions, and in response to this, paper fingerprint information matching processing is executed.

  In the paper fingerprint information matching process when the paper fingerprint information matching tab is pressed, the CPU 301 reads the paper fingerprint information sent from the paper fingerprint information acquisition unit 607 to the RAM 302 and stored in the HDD 304 onto the RAM 302. Also, the read paper fingerprint information is collated with other paper fingerprint information read out on the RAM 302. The other paper fingerprint information refers to other paper fingerprint information in the HDD 304, paper fingerprint information obtained by decoding other code image data in the HDD 304, and paper fingerprint information registered in the server. means. When the encoded image data obtained by encoding the paper fingerprint information from the server is obtained, the CPU 301 temporarily stores the encoded image data in the RAM 302 and performs a decoding process. The obtained paper fingerprint information is converted into the paper fingerprint information. Used for information verification processing.

  In the paper fingerprint information matching process when the tab of the paper fingerprint information registration process is pressed, the paper fingerprint information read out on the RAM 302 is supplied from the scanner image processing unit 332 or the compression unit 333 and sent to the RAM 302. is there. The one paper fingerprint information is stored in the HDD 304 as needed and is read out on the RAM 302. The other paper fingerprint information is obtained by optically reading the target paper with the scanner unit 13, sent from the paper fingerprint information acquisition unit 607 to the RAM 302, and stored in the HDD 304 as follows. Selected information. That is, the paper fingerprint information of the area selected in step 1306 in FIG. 13 among the paper fingerprint information stored in the HDD 304 is read out on the RAM 302. Further, the other paper fingerprint information includes other paper fingerprint information in the HDD 304, other paper fingerprint information obtained by decoding the encoded image data in the HDD 304, and paper fingerprint information registered in the server. When the encoded image data obtained by encoding the paper fingerprint information from the server is obtained, the CPU 301 temporarily stores the encoded image data in the RAM 302 and performs a decoding process. The obtained paper fingerprint information is converted into the paper fingerprint information. Used for information verification processing.

  FIG. 10 is a flowchart showing the paper fingerprint information matching process. Each step of this flowchart is centrally controlled by the CPU 301.

  This process starts when the paper fingerprint information collation tab 809, which is a collation instruction for paper fingerprint information, is pressed. In step 1001, paper fingerprint information obtained by decoding the encoded image data or paper fingerprint information registered in the server. Is taken out from the RAM 302.

  In step 1002, in order to collate the paper fingerprint information sent from the paper fingerprint information acquisition unit 607 with the paper fingerprint information taken out in step 1001, the two pieces of paper fingerprint information are obtained using equation (1). The matching degree is calculated. Assuming that one paper fingerprint information is obtained by shifting the other paper fingerprint information, an error image (E) between the two paper fingerprint information is obtained as follows. That is, in the function shown in Expression (1), the position is shifted for each pixel and the value obtained by the function of Expression (1) is minimized, that is, where the difference between the two pieces of paper fingerprint information is the smallest. An error image (E) of fingerprint information is obtained.

In the equation (1), α ₁ is mask data in the paper fingerprint information extracted (registered) in step 1001. f ₁ is gray scale image data in the paper fingerprint information extracted (registered) in step 1001. alpha ₂ is the mask data of the sent from the paper fingerprint information acquisition unit 507 in (now retrieved freshly) paper fingerprint information in step 1002. f ₂ is a grayscale image data sent from the paper fingerprint information acquisition unit 507 in (now retrieved freshly) paper fingerprint information in step 1002.

  A specific method will be described with reference to FIGS. FIGS. 19A and 19B are image diagrams of the registered paper fingerprint information and the paper fingerprint information obtained this time, respectively. Assume that each pixel is composed of horizontal n pixels and vertical m pixels.

  In the function shown in Expression (1), i and j are shifted by 1 pixel in the range of −n + 1 to n−1 and −m + 1 to m−1, respectively, and the registered paper fingerprint information and just obtained this time. (2n−1) × (2m−1) error values E (i, j) of the paper fingerprint information of are obtained. That is, E (−n + 1, −m + 1) to E (n−1, m−1) are obtained.

  FIG. 20A shows an image diagram in which the upper left pixel of the registered paper fingerprint information is overlapped by the lower right pixel of the obtained paper fingerprint information. In this state, the value obtained by the function of Expression (1) is E (−n + 1, −m + 1). FIG. 20B shows an image diagram in which the paper fingerprint information obtained this time is moved to the right by one pixel as compared with FIG. In this state, a value obtained by the function of Expression (1) is E (−n + 2, −m + 1). Similarly, calculation is performed while moving the paper fingerprint information just obtained this time. In FIG. 20C, the paper fingerprint information just obtained this time is moved to a position where it overlaps with the registered paper fingerprint information, and E (0,-(m-1)) is obtained. Further, in FIG. 20D, the paper fingerprint information obtained this time is moved to the right end to obtain E (n−1, −m + 1). Thus, when shifted in the horizontal direction, i of E (i, j) is added one by one.

  Similarly, in FIG. 21A, the paper fingerprint information obtained this time is moved by one pixel downward in the vertical direction as compared with FIG. 20A, and the value of E (−n + 1, −m + 2) is obtained. Ask for.

  Furthermore, FIG. 21 (B) moves the paper fingerprint information obtained this time to the right end with respect to FIG. 21 (A) and obtains the value of E (n−1, −m + 2).

  FIG. 22A shows the case where the registered paper fingerprint information and the paper fingerprint information obtained this time are at the same position, and the value of E (i, j) at this time is represented by E (0,0). And

  Similarly, the calculation is performed while shifting the images so that each paper fingerprint information overlaps at least one pixel. Finally, E (n−1, m−1) is obtained as shown in FIG.

  In this way, a set of (2n−1) × (2m−1) error values E (i, j) is obtained.

Here, in order to consider the meaning of the equation (1), i = 0, j = 0, and α ₁ (x, y) = 1 (where x = 0 to n, y = 0 to m ) And α ₂ (x−i, y−j) = 1 (where x = 0 to n and y = 0 to m). That is, α ₁ (x, y) = 1 (where x = 0 to n, y = 0 to m), and α ₂ (xi, y−j) = 1 (where x = 0). E (0,0) in the case of .about.n, y = 0 to m).

  Note that i = 0 and j = 0 indicate that the registered paper fingerprint information and the paper fingerprint information obtained this time are at the same position as shown in FIG.

Here, α ₁ (x, y) = 1 (where x = 0 to n, y = 0 to m) indicates that all pixels of the registered paper fingerprint information are bright. In other words, when the registered paper fingerprint information is acquired, it indicates that no color material such as toner or ink or dust has been placed on the paper fingerprint acquisition area.

Further, α ₂ (x−i, y−j) = 1 (where x = 0 to n, y = 0 to m) indicates that all pixels of the paper fingerprint information acquired this time are bright. In other words, when the paper fingerprint information just acquired is acquired, it indicates that no color material such as toner or ink or dust is on the paper fingerprint acquisition area.

Thus, when α ₁ (x, y) = 1 and α ₂ (x−i, y−j) = 1 hold in all pixels, the equation (1) becomes

Will be expressed.

This {f ₁ (x, y) −f ₂ (x, y)} ² is the gray scale image data in the registered paper fingerprint information and the gray scale image data in the paper fingerprint information just extracted. The square value of the difference between Therefore, this equation (1) is the sum of the squares of the differences in each pixel between the two pieces of paper fingerprint information. That is, the more pixels f ₁ (x, y) and f ₂ (x, y) are similar, the smaller this E (0, 0) will be.

What has been described above is how to obtain E (0,0), but other E (i, j) are obtained in the same manner. Incidentally, since E (i, j) takes a smaller value as the number of pixels in which f ₁ (x, y) and f ₂ (x, y) are similar is larger,
If E (k, l) = min {E (i, j)}, the position when the registered paper fingerprint information is acquired, and the position when the paper fingerprint information just acquired is acquired It can be seen that they were shifted from each other by k and l.

<Significance of α>
The numerator of formula (1) means the result of multiplying {f ₁ (x, y) -f ₂ (xi, yj)} ² by α ₁ and α ₂ (exactly Is further determined by the Σ symbol). Α ₁ and α ₂ indicate 0 for a dark pixel and 1 for a light pixel.

Accordingly, when one (or both) of α ₁ and α ₂ is 0, α ₁ α ₂ {f ₁ (x, y) −f ₂ (xi, y−j)} ² Will be 0.

  That is, when one or both (or both) of the paper fingerprint information has a dark pixel, the density difference between the pixels is not considered. This is for ignoring pixels on which dust or color material has been placed.

As a result of this processing, the total number increases or decreases depending on the Σ symbol, so normalization is performed by dividing by the total number Σα ₁ (x, y) α ₂ (xi, y−j). Note that an error value E (i, j) in which Σα ₁ (x, y) α ₂ (x−i, y−j) in the denominator of Expression (1) becomes 0 is a set of error values (E (-(N-1),-(m-1)) to E (n-1, m-1)) are not included.

<Determination method of matching degree>
As described above, when E (k, l) = min {E (i, j)}, the position when the registered paper fingerprint information is acquired and the paper fingerprint information just acquired are acquired. It can be seen that the positions were shifted by k and l from each other.

  Subsequently, a value indicating how much the two pieces of paper fingerprint information are similar (this value is referred to as a matching degree) is obtained using the E (k, l) and other E (i, j). .

First, a set of error values obtained by the function of (1) (for example, E (0,0) = 10 *, E (0,1) = 50, E (1,0) = 50, E (1,1 ) = 50) to obtain the average value (40). ... (A)
Note that * is not related to the value. It is simply a symbol indicating that it should be noted.

Next, each error value (10 *, 50, 50, 50) is subtracted from the average value (40) to obtain a new set (30 *, −10, −10, −10). .... (B)
Then, a standard deviation (30 × 30 + 10 × 10 + 10 × 10 + 10 × 10 = 1200, 1200/4 = 300, √300 = 10√3 = about 17) is obtained from this new set. Then, the new set is divided by 17 to obtain a quotient (1 *, -1, -1, -1). .... (C)
And let the maximum value of the calculated | required values be a matching degree (1 *). The value 1 * corresponds to the value E (0,0) = 10 *. In this case, E (0,0) is a value that satisfies E (0,0) = min {E (i, j)}.

<Conceptual explanation of how to determine the degree of matching>
The process of performing the matching degree determination method eventually calculates how far the smallest error value in the plurality of error value sets is from the average error value (A and B).

  Then, the degree of matching is obtained by dividing the degree of separation by the standard deviation (C).

  Finally, a matching result is obtained by comparing the matching degree with a threshold (D).

  The standard deviation means an average value of “difference between each error value and the average value”. In other words, the standard deviation is a value indicating how much variation occurs in the entire set.

  By dividing the above degree of separation by such an overall variation value, how small is min {E (i, j)} in the set E (i, j) (projectingly small or slightly small) ) Will be understood.

  Then, it is determined to be valid when min {E (i, j)} is very prominent and small in the set E (i, j), and is invalid otherwise (D).

<Reason why min {E (i, j)} is determined to be effective only when it is very small in the set E (i, j)>
Here, it is assumed that the registered paper fingerprint information and the paper fingerprint information just acquired are acquired from the same paper.

  Then, there should be a place (shift position) where the registered paper fingerprint information and the paper fingerprint information just acquired are very consistent. At this time, at this misalignment position, the registered paper fingerprint information and the paper fingerprint information just acquired are very coincident, so E (i, j) should be very small.

  On the other hand, if the position is slightly shifted from this position, the registered paper fingerprint information and the paper fingerprint information just acquired are no longer relevant. Therefore, E (i, j) should be a normal large value.

  Therefore, the condition that “two pieces of paper fingerprint information are acquired from the same paper” matches the condition that “the smallest E (i, j) protrudes and is small in the set E (i, j)”.

  Return to <paper fingerprint information collation processing>.

  In step 1003, “valid” and “invalid” are determined by comparing the matching degree of the two pieces of paper fingerprint information obtained in step 1002 with a predetermined threshold value. Note that the degree of matching may be referred to as similarity. A comparison result between the matching degree and a predetermined threshold value may be referred to as a matching result.

  The description of the controller 11 has been described above.

<Operation when the tab for paper fingerprint information registration processing is pressed>
Next, a paper fingerprint information registration process executed when the user presses the paper fingerprint information registration tab 808 shown in FIG. 8 and then presses the start key will be described with reference to the flowchart of FIG. Pressing the paper fingerprint information registration tab 808 by the user corresponds to a feature data registration processing instruction, and in response to this, paper fingerprint information registration processing is executed.

  The user sets a blank sheet in the document feeder 201 and presses the tab for the paper fingerprint information registration process. In step 1101, the CPU 301 controls to send the image data obtained by reading the blank paper with the scanner unit 13 to the scanner image processing unit 312 via the scanner I / F 311.

  In step 1102, the scanner image processing unit 312 sets a gain adjustment value smaller than a general gain adjustment value in the shading correction unit 600. Then, each luminance signal value obtained by applying the small gain adjustment value to the image data is output to the paper fingerprint information acquisition unit 607. Thereafter, as shown in FIG. 9, the paper fingerprint information acquisition unit 607 acquires the paper fingerprint information based on the output data. Then, the obtained paper fingerprint information is sent to the RAM 302 using a data bus (not shown). After this operation is performed on a plurality of predetermined areas (total of 20 areas exemplified by 1401 etc.) on the paper 1405 as shown in FIG. 14 and all the paper fingerprint information on the paper is stored in the RAM 302, All the paper fingerprint information of one sheet is transferred to the HDD 304 and stored. Further, regarding the paper fingerprint information stored in the RAM 302, when the processing in step 1102 is completed, the processing in step 1103 is started.

  In step 1103, the CPU 301 encodes the paper fingerprint information to generate a code image, temporarily stores the encoded information (encoded data) in the RAM 302, and then associates it with a plurality of paper fingerprint information on the paper. The encoded information is stored in the HDD 304 for each area in FIG. Next, in step 1104, it is determined whether or not paper remains in the document feeder 201. If blank paper still remains in the 201 document feeder, the processing from step 1101 is repeated, and the paper fingerprint information of all blank paper is read and encoded. When the paper on the document feeder 201 runs out, the CPU 301 ends the processing.

  Next, the user reads the paper fingerprint information, takes out the blank paper that has been encoded, from the document feeder 201, and prints the paper fingerprint at the portion of the paper cassette where 203, 204, 205 or manual paper is fed. Load the scanned paper. Next, when the user presses a print start tab indicated by reference numeral 810 in FIG. 8, the image processing apparatus feeds the blank paper after reading the paper fingerprint information as described above, and forms an image on the paper. The operation to start is started.

  Next, using the flowchart of FIG. 12, for example, an operation when rendering and saving one page of PDL data will be described.

  First, the CPU 301 once stores the network packet data transferred from the external host computer via the LAN 50 in the RAM 302 via the network I / F 306. The CPU 301 analyzes the stored packet data, extracts PDL data, and stores the PDL data in the HDD 304. Next, the PDL data is taken out from the HDD 304 again and rendered by the RIP unit 328.

  In step 1202, the compression unit 329 divides the new image data generated by the RIP unit 328 into blocks of 32 pixels × 32 pixels to generate tile data. Further, the compression unit 329 compresses the image data including the plurality of tile data.

  In step 1203, the CPU 301 sends the image data compressed by the compression unit 329 to the RAM 302 and stores it. The image data is sent to the image conversion unit 317 as necessary, subjected to predetermined image processing, and then sent to the RAM 302 again for storage. Next, the CPU 301 stores the image data on the RAM 302 in the HDD 304 and ends the processing.

  Next, the operation when the CPU 301 detects the non-image area of the image rendered as described above will be described using the flowchart of FIG. The function of the non-image area detecting means is realized by the CPU 301 operating according to the flowchart of FIG. First, in step 1301, image data stored in the HDD 304 is read and transferred to the RAM 302. Next, in step 1302, the compressed image is expanded using the expansion unit 318, and then in step 1303, the image rendered at, for example, 1200 dpi is scaled to a 300 dpi image using the scaling unit 321. . Next, in step 1304, the CPU 301 uses the multi-value binary unit 324 to convert, for example, 8-bit multi-value image data per pixel into a monochrome binary image. The image data converted into binary data is stored in the RAM 302 again. As the image data stored in the RAM 302, for example, images 1402, 1403, and 1404 on one page as shown in FIG. 14 are stored. Next, in step 1305, the CPU 301 analyzes binary image data as shown in FIG. 14 by reading the RAM 302, and determines a non-image area in one page. Next, in step 1306, the following processing is performed. That is, as a result of the analysis of the non-image area, among the plurality of white fixed areas obtained by reading the paper fingerprint using the scanner unit 13 described above with reference to FIG. 11, for example, the area A, area B, and area C in FIG. For example, the one located in the non-image area is selected as the paper fingerprint area, and the process is terminated. Here, the CPU 301 can store the selected paper fingerprint area information in the RAM 302 in association with the image to be printed on the white paper obtained by reading the paper fingerprint. That is, the image to be printed on the white paper obtained by reading the paper fingerprint includes the rendered image data described in FIG. 13 or the image data read by the scanner unit and stored in the HDD. Furthermore, the selected paper fingerprint area information, which is characteristic data, can be stored in the RAM 302 in association with attribute data, which is information for specifying image data. The CPU 301 constitutes this association means. Note that the fixed area data not selected in step 1306 can be discarded.

  Next, the operation during printing will be described using the flowchart of FIG. First, in step 1501, the CPU 301 reads the image data to be printed stored in the HDD 304 as described above and transfers it to the RAM 302. Note that the image data to be printed stored in the HDD 304 includes image data read using the scanner unit 13 in addition to the rendered image data described above. In step 1502, the CPU 301 instructs the printer unit 14 to read paper fingerprints at a plurality of locations before feeding the paper manually or set in paper cassettes 203, 204, and 205. That is, this corresponds to feeding a sheet as an original on which the image data to be printed is printed. In step 1503, the CPU 301 uses the internal scanner unit 1705, the scanner image processing unit 332, and the compression unit 333 to use the paper fingerprint of the area corresponding to the area selected in step 1306 of the fed paper. Information is acquired on the paper transport path. This internal scanner unit 705 only needs to read the area selected in 1306 on the conveyed paper. For example, it is only necessary to read a part of the paper in the width direction, and it can be made smaller than a reading unit that reads the entire surface of the document. Of course, the entire original may be read. For example, the paper fingerprint information of area C in FIG. 14 is acquired, and the data is transferred to the RAM 302. Next, in step 1504, the CPU 301 includes data that matches the paper fingerprint information of the area C on the supplied paper (on the surface of the recording medium) transferred to the RAM 302 in the paper fingerprint information stored in the HDD 304. Search whether there is. If it is determined in step 1505 that matching paper fingerprint information does not exist in the HDD 304, the process proceeds to step 1506, an error message is displayed on the operation unit 12, and the process ends. If there is matching paper fingerprint information in the HDD 304 in step 1505, in step 1507, the data encoded in the previous (S1103) at the position corresponding to the areas A and B in FIG. The data is stored in the RAM 302 as data. At this point, the encoded information of the paper fingerprint information at positions other than A and B is not used, and may be deleted from the HD 304. As a result, the capacity of HD304 can be used effectively. The code image data is an image obtained by converting paper fingerprint information into a barcode or a watermark image converted into a digital watermark.

  In step 1508, the printer image processing unit 315 performs image data editing according to attribute data attached to the image data. This process is the process shown in FIG. In this step, the encoded image data read in step 1507 and the (original) image data are combined. Then, the halftone correction unit 706 performs halftone processing on the composite image data obtained by the synthesis in accordance with the number of gradations of the printer unit to be output. The composite image data after the halftone process is sent to the printer unit 14 via the printer I / F 314. The printer unit 14 forms an image of the composite image data on the output paper, and the process ends. As a result, the image can be correctly printed on the paper that is correctly recognized as the original paper.

<Operation when the tab for fingerprint information collation processing on the paper pattern is pressed>
Next, an operation when the start key is pressed after the user has pressed the paper fingerprint information collation tab 809 shown in FIG. 8 will be described with reference to FIG.

  In step 1601, the CPU 301 controls the document read by the scanner unit 13 to be sent as image data to the scanner image processing unit 312 via the scanner I / F 311.

  In step 1602, the scanner image processing unit 312 performs the processing described in <Detailed description of the scanner image processing unit 312 (FIG. 6)> on the image data, and generates attribute data together with new image data. . Further, this attribute data is attached to the image data.

  Further, in step 1602, the paper fingerprint information acquisition unit 607 in the scanner image processing unit 312 acquires paper fingerprint information (such as gain adjustment of the shading correction unit 600 to acquire paper fingerprint information). Is as described above). Then, the obtained paper fingerprint information is sent to the RAM 302 using a data bus (not shown).

  Further, in step 1602, when there is a code image, the decoding unit 608 in the scanner image processing unit 312 decodes the code image to obtain information. Then, the acquired information is sent to the RAM 302 using a data bus (not shown).

  In step 1603, the CPU 301 performs a paper fingerprint information matching process. This paper fingerprint information matching process is as described in <Paper fingerprint information matching process>.

  In step 1604, the CPU 301 controls to display the result (valid or invalid) obtained by the <paper fingerprint information matching process> on the display screen of the operation unit 12.

  As described above, a plurality of paper fingerprint information on an image recording medium such as paper is read in advance, and the scanner inside the machine simply reads the paper fingerprint information in a certain fixed area. It is possible to make a match with the paper fingerprint information. For this reason, it is not necessary for the scanner inside the machine to read the entire page, and the cost of the scanner inside the machine can be reduced.

[Example 2]
In the second embodiment, paper fingerprint information of an image recording medium such as paper is stored in a server, and the paper fingerprint information is acquired from the server when printing. Detailed description of the same parts as those in the first embodiment will be omitted.

  The second embodiment differs from the first embodiment in that a server 1801 for storing paper fingerprint information is provided on the network as shown in FIG. The means for storing the paper fingerprint information is merely replaced with the server 1801 from the image forming apparatus, and the processing itself is the same as the details described in the first embodiment. Paper used in printers and copiers can be obtained from the manufacturer that manufactures the paper, but when the paper is manufactured, paper fingerprint information at a plurality of locations on the paper is obtained and the paper on one page as shown in FIG. Are registered in the server for each paper. Regarding the paper fingerprint registration method, paper fingerprint information is acquired for each paper according to the flowchart shown in FIG. 9 described in the first embodiment, and <paper fingerprint information encoding processing> is also executed if necessary. It is assumed that the data is stored in the server 171801.

  Next, a case where print data is printed on paper will be described. This is performed according to the flowchart of FIG. 15. In step 1504, the network 50 is accessed via the network I / F 306 instead of the HDD 304, and the paper fingerprint information is inquired to the server 1801. The <paper fingerprint information collation process> described above is performed on the server. Even if the user registers the server address on the network in advance, the address is linked from, for example, a barcode on a paper wrapping paper, and the server 1801 is automatically registered by a printer or copier. It is also possible to leave it. If paper fingerprint information is detected as a result of the inquiry, the processing after step S1507 in FIG. 15 can be performed to synthesize the paper fingerprint code data with the image data to be printed and print it.

  By storing the paper fingerprint information (and the encoded image thereof) in the server 1801, it becomes possible for a person other than the user to register the paper fingerprint without using the scanner or copying machine used by the user. Furthermore, for a user who owns a plurality of copiers, printers, and scanners, paper fingerprint information can be managed by a single server.

(Other examples)
Further, the present invention can be applied to a system constituted by a plurality of devices (for example, a computer, an interface device, a reader, a printer, etc.), and can also be applied to an apparatus (multifunction device, printer, facsimile machine, etc.) comprising a single device. It is also possible.

  Another object of the present invention is that a computer (or CPU or MPU) of a system or apparatus reads and executes the program code from a storage medium that stores the program code for realizing the procedure of the flowchart shown in the above-described embodiment. Is also achieved. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment. Therefore, the program code and a storage medium storing the program code also constitute one of the present invention.

  As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like is used. be able to.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the following cases are included. That is, the case where the OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing. It is.

  Furthermore, the program code read from the storage medium can be written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. In this case, based on the instruction of the written program code, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing. The

1 is a diagram illustrating an overall configuration of an image forming system. 1 is an external view of an input / output device of an image forming apparatus. 1 is a diagram illustrating an overall configuration of an image forming apparatus. It is a figure which shows tile data notionally. It is the schematic which shows the reading area | region of the paper fingerprint on paper. It is a block diagram of a scanner image processing unit. It is a block diagram of a printer image processing unit. It is explanatory drawing of the copy screen of an operation part. It is a flowchart of a paper fingerprint information acquisition process. It is a flowchart of a paper fingerprint information collation process. It is a flowchart of the process which reads a paper fingerprint from blank paper. It is a flowchart of a rendering process. It is a flowchart of a non-image area detection process of an image. It is a figure which shows the paper fingerprint area | region and image of paper. It is a flowchart of a printing process. It is a flowchart of a paper fingerprint collation process. 1 is an internal configuration diagram of an image forming apparatus. 1 is a diagram illustrating an overall configuration of an image forming system. It is a figure which shows the registered paper fingerprint information and the paper fingerprint information obtained this time. (A) is a diagram showing how to determine E _{1 × 1} , (B) is a diagram illustrating how to determine E _{2 × 1} , (C) is a diagram illustrating how to determine _{En × 1} , and (D) is E It is a figure which shows how to obtain | require _2n-1x1 . (A) is a figure which shows how to obtain | require E1 _{* 2} , (B) is a figure which shows how to obtain | require _{E2n-1 * 2} . (A) is a figure which shows how to obtain | require _{En * m} , (B) is a figure which shows how to obtain | require _{E2n-1 * 2m-1} .

Explanation of symbols

1401, A, B, C area 1402, 1403, 1404 image 1405 paper

Claims (13)

  Referring to first storage means for storing optically detected feature data at a plurality of locations on the surface of the image recording medium, and image data to form an image on the image recording medium, the image data is the image Non-image area detecting means for detecting a non-image area not recorded on the recording medium, and the non-image area detecting means among the feature data of a plurality of locations of the image recording medium stored in the first storage means Feature data selection means for selecting feature data corresponding to the non-image area detected by the second feature, and second storage for storing the feature data selected by the feature data selection means as feature data for specifying an image recording medium And an image processing apparatus.   The image processing apparatus according to claim 1, further comprising means for discarding feature data not selected by the feature data selection means.   The image processing apparatus according to claim 1, further comprising an encoding unit that encodes the feature data stored in the second storage unit.   The image processing apparatus according to claim 3, further comprising a combining unit configured to combine the data encoded by the encoding unit with the image data.   2. The image processing apparatus according to claim 1, further comprising third storage means for storing the feature data stored in the second storage means in association with the image data.   The image processing apparatus according to claim 5, wherein the third storage unit further stores information for specifying the associated feature data and image data.   The image processing apparatus is an image forming apparatus, and an image forming unit for forming an image corresponding to the image data on an image recording medium, and a surface of the image recording medium on a conveyance path in the middle of being supplied to the image forming unit First reading means for optically reading a part in the upper width direction, feature data on the surface of the image recording medium detected based on a reading result by the first reading means, and the second storage means Comparing means for comparing a plurality of feature data stored in the recording means, and means for specifying an image recording medium supplied to the image forming means based on a comparison result by the comparing means The image processing apparatus according to claim 1.   The image processing apparatus according to claim 7, further comprising second reading means for optically reading the surface of the image recording medium and detecting characteristic data stored in the first storage means.   The image forming unit further includes an encoding unit that encodes the feature data stored in the second storage unit, and the image forming unit displays an image corresponding to the data encoded by the encoding unit on an image recording medium. The image processing apparatus according to claim 7, wherein the image processing apparatus is formed.   The image data further includes a combining unit that combines the data encoded by the encoding unit with the image data, and the image forming unit includes an image corresponding to the image data combined with the data encoded by the encoding unit. The image processing apparatus according to claim 9, wherein the image processing apparatus is formed on an image recording medium.   The server further includes means for acquiring the feature data via a network from a server that holds optically detected feature data at a plurality of locations on the surface of the image recording medium, and the first storage means includes the acquisition The image processing apparatus according to claim 7, wherein the feature data is stored. Using the image processing device according to any one of claims 7 to 11,
In response to the feature data collation processing instruction, the feature data of the surface of the image recording medium before being supplied to the image forming unit using the first reading unit is acquired,
An image processing method, wherein the comparison means compares the acquired feature data with other feature data in the second storage means. Using the image processing apparatus of claim 10;
In response to the characteristic data registration processing instruction, the second reading unit optically reads the image recording medium,
Storing feature data detected based on a reading result by the second reading unit in the first storage unit;
The non-image area detecting means refers to image data to be recorded on the image recording medium, detects a non-image area in which the image data is not recorded on the image recording medium,
Feature data corresponding to the non-image area detected by the non-image area detection means among the feature data of the plurality of locations of the image recording medium stored in the first storage means by the feature data selection means. Selected,
Storing the selected feature data in the second storage means as feature data for specifying an image recording medium;
The first reading unit optically reads a part in the width direction on the surface of the image recording medium on a conveyance path in the middle of being supplied to the image forming unit,
Comparing the feature data on the surface of the image recording medium detected based on the reading result by the first reading means with the plurality of feature data stored in the second storage means by the comparing means;
Based on the comparison result by the comparison means, it is determined that the feature data on the surface of the image recording medium read by the first reading means matches any one of the plurality of feature data stored in the second storage means. In this case, the image forming unit forms an image corresponding to the image data combined by the combining unit on the image recording medium from which the characteristic data is read by the first reading unit. Image processing method.

Images