JP2005057797A - Image processing apparatus and method, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide techniques with which additional information is surely decoded from an image with the additional information added. <P>SOLUTION: This image processing apparatus is provided with an addition means for adding first additional information including an error-correcting code having a first error-correcting capability to an input image so as to be difficult to identify for human eyes, and for adding second additional information including an error-correcting code having a second error-correcting capability different from the first error-correcting capability so as to be difficult to identify for human eyes, and an output means for outputting the image with the predetermined additional information added by the addition means to an image forming part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus and method capable of adding additional information to an input image, and a storage medium storing the method.

  In recent years, image processing apparatuses such as color printers and color copiers are capable of forming high-quality images due to improved performance. Under such circumstances, it is becoming possible to form an image similar to securities such as banknotes, and a technique for preventing such an action is known. (Refer to patent document 1 etc.).

  For example, an addition method is known in which a dot pattern indicating the serial number of the image processing apparatus is additionally printed together with a color image to be printed.

  This dot pattern is periodically printed on the entire screen and added only to the yellow plane.

The dot pattern (additional information) addition method as described above is different for each manufacturer that manufactures each image processing apparatus. In order to decode the additional information such as the production number based on a certain formed image, It is necessary to sequentially use a decoding method according to each manufacturer's additional method.
Japanese Patent Laid-Open No. 04-294682

  However, when the number of manufacturers that manufacture the device is large, there is a problem that the load for sequentially using the decoding method is large as described above. In particular, when the above-described decoding is performed by software processing or the like, this problem appears remarkably.

  The present invention has been made in view of the above-described conventional example, and can efficiently decode additional information from an image in which additional information may be difficult to be identified by human eyes by a plurality of types of methods. It aims at providing the information addition technology which can be done.

  It is another object of the present invention to provide a technique capable of reliably decoding additional information from an image to which additional information is added.

  In order to solve the above problems, the image processing apparatus of the present invention adds the first additional information including the error correction code having the first error correction capability to the input image so that it is difficult to be recognized by human eyes, Addition means for adding second additional information including an error correction code having a second error correction capability different from the first error correction capability so that it is difficult for human eyes to identify, and predetermined additional information is added by the additional means. And an output unit that outputs the added image to the image forming unit.

  According to the present invention, the first additional information including the error correction code having the first error correction capability is added to the input image so that it is difficult for human eyes to identify, and is different from the first error correction capability. Since the second additional information including the error correction code having the second error correction capability is added to be difficult to be identified by the human eye, a plurality of additional information to be added to the image that is difficult to be identified by the human eye When the importance levels are different, it is possible to reliably decode the additional information having a high importance level.

  In this embodiment mode, an image processing apparatus using color electrophotographic technology is described. However, the present invention is not limited to this, and can also be applied to an image processing apparatus using a technique such as an inkjet method or a thermal transfer method. Further, the present invention is not limited to the invention of the apparatus, and a method for performing the processing described below, software for performing the method, and the like are also included in the scope of the present invention.

  In this embodiment, the input image data is multi-valued image data of 8 bits for each color of M (magenta), C (cyan), Y (yellow), and K (black). Input in frame order.

  The image processing apparatus (laser beam printer) of the present embodiment has a resolution of 600 dpi, and a dot pattern indicating additional information for forgery tracking is added only to the Y plane. In this way, it is possible to make it difficult for human eyes to identify as much as possible, and even a color image with additional information added can be used in the same way as the original color image before adding the additional information. Is possible. The present invention is not limited to the case where additional information for forgery tracking is added. In other words, the present invention includes the case where the name of the author who created the original image or the work name of the image is used as additional information.

  FIG. 1 shows the configuration of an image processing apparatus used in the following embodiments.

  An image processing unit 1000 sequentially inputs multi-value image data composed of M, C, Y, and K from an external device or another device inside the device, adds additional information to be described later, and then images of each color. A laser light emitting unit 1001 that outputs data to the laser light emitting unit 1001 emits a laser beam L, which will be described later, modulated according to the input image data.

  The photosensitive drum 100 is uniformly charged to a predetermined polarity by the charger 101, and a magenta first latent image, for example, is formed on the photosensitive drum 100 by exposure with the laser beam L. Next, in this case, a required developing bias voltage is applied only to the magenta developing device Dm to develop the magenta latent image, and a magenta first toner image is formed on the photosensitive drum 100.

  On the other hand, the transfer paper P is fed at a predetermined timing, and immediately before the leading edge reaches the transfer start position, a transfer bias voltage (+1.8 KV) having a polarity opposite to that of the toner (for example, plus polarity) is applied to the transfer drum 102. Then, the first toner image on the photosensitive drum 100 is transferred to the transfer paper P, and the transfer paper P is electrostatically attracted to the surface of the transfer drum 102. Thereafter, the magenta toner remaining on the photosensitive drum 100 is removed by the cleaner 103 to prepare for the next color latent image formation and development process.

  Next, as in the case of magenta, a second latent image of cyan is formed on the photosensitive drum 100 by the laser beam L, and then a second developer on the photosensitive drum 100 is formed by the cyan developing device Dc. The latent image is developed to form a cyan second toner image. The cyan second toner image is transferred onto the transfer paper P in accordance with the position of the first magenta toner image transferred onto the transfer paper P. In transferring the second color toner image, a bias voltage of +2.1 KV is applied to the transfer drum 102 immediately before the transfer paper reaches the transfer portion.

  Similarly, the yellow and black third and fourth latent images are sequentially formed on the photosensitive drum 100, and are sequentially developed by the developing devices Dy and Db, respectively, and transferred to the transfer paper P in advance. The third and fourth toner images of yellow and black are sequentially transferred in alignment with the image, and a full-color image in which the four color toner images are superimposed on the transfer paper P is formed.

  Next, additional information for forgery tracking added by the image processing apparatus of the present embodiment will be described.

  FIG. 2 shows a state in which additional information is added to the image represented by the input image data in the present embodiment. As described above, in the present embodiment, the additional information is added only to the Y plane. Therefore, FIG. 2 shows an image indicated by the Y plane of a color image composed of Y, M, C, and K planes. Shows about.

  Each dot 201 scattered in FIG. 2 is a minute area dot composed of a plurality of pixels. This dot is hereinafter referred to as an AddOn dot.

  In the drawing, an area 202 indicated by shading is a unit area indicating additional information added to the color image (yellow plane) in the present embodiment. This unit area 202 is periodically present in the original color image (yellow plane). In this way, the additional information can be analyzed with reference to any region of the color image finally formed after the additional information is added.

  The unit region 202 includes a plurality of lines 203 called AddOn lines, and in the present embodiment, 16 lines exist in the main running difference direction. Note that one AddOn dot described above is arranged on each AddOn line in the unit region 202. As will be described later, the additional information can indicate various types of information depending on the position (phase) of the AddOn dot on each AddOn line. It is possible to assign a product name, a manufacturing number, a manufacturer name, etc. of the image processing apparatus to the various information.

  Further, a reference dot 204 is added in the unit area 202 so as not to mistakenly identify the add-on dot arrangement direction for indicating additional information. The position of this reference dot is always fixed. In the present embodiment, the reference dot 204 is added together with the AddOn dot on the 0th and 7th AddOn lines. In this way, the AddOn line at the beginning of the unit region can be determined, and the direction of the arrangement of the AddOn lines 0 to 15 can be determined.

  FIG. 4 is a block diagram of an AddOn dot addition processing unit included in the image processing unit 1000 of FIG. Additional information (product name, serial number, manufacturer name, etc.) stored in the EEPROM 401 is automatically loaded into the register 402 in the CPU when the image processing apparatus is turned on.

  FIG. 3 shows the internal configuration of the register 402. In the register 402, codes from F000 to F00A are stored. A total of 12 bits including 8 bits of F000 address and upper 4 bits of F0001 addressed by hatching in the figure is an area dedicated to the manufacturer name (manufacturer ID) described above, and is assigned to each manufacturer that manufactured the image processing apparatus. Are stored. In other areas (the lower 4 bits of address F0001 and F002 to F00A), codes indicating the product name, serial number, etc. of the image processing apparatus uniquely determined by each manufacturer are entered.

  In addition to the additional information described above, the register 402 also stores a fixed bit that contains a fixed value and a parity bit for parity check.

  When the image processing apparatus receives a command to print a color image, the additional information (product name, serial number, manufacturer name, etc.) is input to the encryption circuit 405 and encrypted.

  This encrypted additional information is input to the parity check circuit 406, where parity and fixed bits are checked. If an error occurs, control is performed to stop the printing operation because the additional information has been modified.

  The main scanning counter 407 performs a counting operation according to the clock signal PCLK in the main scanning direction of the image data, and sends ON at a position where an AddOn dot should be added according to the code loaded from the parity check 406. The sub-scanning counter 408 performs a counting operation in accordance with the clock signal BD in the sub-scanning direction and sends ON on the AddOn line.

  The AddOn dot generation circuit 409 receives the AddOn dot shape parameter stored in the ROM 403 in the CPU, and the AddOn permission signal, the main scanning counter 407, and the sub-scanning counter 408 that are turned on only when the yellow plane of the image data is sent are turned on. Only at that time, an AddOn dot is generated and the AddOn signal is turned ON and transmitted.

  The AddOn addition circuit 404 sends the input image data as it is if the AddOn signal is OFF, and converts it to AddOn dots if the AddOn signal is ON. Thereby, additional information (AddOn dots) is formed as shown in FIG.

  Next, a method for analyzing additional information added to image data according to the present embodiment, that is, a method for expressing additional information with AddOn dots will be described.

  FIG. 5 is an enlarged view of the nth and n + 1th AddOn lines in the unit region 202 of FIG. The n + 1th AddOn line will be described. The phase difference based on the AddOn dot on the nth AddOn line is assigned to 0 to 7 (3 bits) as shown in the figure. Then, an AddOn dot is added at a position corresponding to 3-bit information to be added in the (n + 1) th AddOn line. Thus, 3-bit information can be represented by one AddOn line (AddOn dot). Therefore, since there are 16 AddOn lines in the present embodiment, it is possible to add additional information of 48 bits in total.

  However, the present invention is not limited to this, and additional information may be added by another method. For example, more additional information may be added by adding a plurality of AddOn dots on each AddOn line.

  The above phase difference analysis is performed by, for example, reading a color image with additional information added by a scanner, extracting only a Y (yellow) plane image to the host computer, and the interval between AddOn dots on the monitor of the host computer. It is possible to measure by measuring. The code of each AddOn line is determined from the measured phase difference, and the determined codes are arranged as shown in FIG. 6 and converted into binary numbers, which are assigned as address information of a00 to a30 and b00 to b112.

  Here, a00 to a32 indicate manufacturer IDs (manufacturer names), and a22, a30, a31, and a32 are parity bits.

  First, when analyzing manufacturer IDs, a00 to a32 are arranged as shown in FIG. 7, and it is confirmed that a22, a30, a31, and a32 are even parity in the direction of the arrow in the figure. If an error occurs in this parity check, the measurement is restarted as a manufacturer ID reading error (analysis error).

On the other hand, if no error occurs in the parity check, the manufacturer ID is obtained by arranging a00 to a21 as follows.
Manufacturer ID = (a21, a20, a12, a11, a10, a02, a01, a00)
In the example of FIG.
Manufacturer ID = (a21, a20, a12, a11, a10, a02, a01, a00)
= 0, 0, 1, 0, 0, 0, 1, 0 (B) = 34 (D)
It becomes.

  Based on the manufacturer ID acquired here, the manufacturer that manufactured the image processing apparatus involved in the formation of the color image is analyzed.

  After analyzing the manufacturer ID, it is possible to analyze additional information such as a product name and a manufacturing number by a method according to each manufacturer. This is because there is a possibility that a method for adding additional information such as a product name and a manufacturing number may be different for each manufacturer. Therefore, a parity bit is added independently to the manufacturer ID, the product name, and the manufacturing number.

  Subsequently, b00 to b112 (including parity bits) indicating additional information such as product name and manufacturing number are analyzed (parity check) independently of the manufacturer ID.

  The additional information of b00 to b112 is obtained by decoding the additional information of b00 to b112 and performing a parity check using a method suitable for each manufacturer, and then obtaining a model number, a machine number, and the like.

  As described above, by adding a parity bit independently to the manufacturer ID (manufacturer name), product name, and manufacturing number (model number, machine number, etc.), additional information of the manufacturer ID and product Even when additional information such as a name and a production number is added to an image by a different method, it is possible to reliably check whether or not the analyzed various additional information is accurate.

  FIG. 9 shows a conceptual diagram of the additional information of the manufacturer ID, the product name, and the manufacturing number added in the above embodiment.

  9, 202 corresponds to the unit area 202 of FIG. The manufacturer ID is added (represented) using the AddOn line (AddOn lines 0 to 3) in the upper area 901 of the unit area 202, and the product name and serial number are the AddOn line (AddOn line) in the lower area 902 of the unit area 202. 4 to 15) are added (expressed).

  A procedure for decoding the additional information will be described with reference to FIG.

  When the decoding is started, the color image is first read by the scanner. However, since the additional information of this embodiment is added to the yellow plane, only the yellow plane is read (step S1). Next, the reference dot is detected, the head of the AddOn line and the direction of the AddOn line are recognized, and the phase difference between the AddOn lines 0 to 3 (AddOn lines 15 and 0, 0 and 1, 1 and 2, 2 and 3) is measured. (Step S2).

  The codes of AddOn lines 0 to 3 are acquired from the measured phase difference (step S3), converted into binary numbers, and assigned to a00 to a32 (step S4). Next, the above-described parity check of FIG. 7 is performed (step S5). If there is an error, the phase difference measurement (step S2) is repeated. On the other hand, if no error occurs, the manufacturer ID is acquired (step S6).

  Next, the phase difference of the AddOn lines 4 to 15 is measured (step S7). From the measured phase difference, the codes of the AddOn lines 4 to 15 are acquired (step S8), binarized, and assigned to b00 to b112 (step S9).

  Here, it is determined whether or not the manufacturer ID acquired in Step S6 indicates Company A (Step S10). If it is Company A, a module for Company A is activated (Step S11). Here, the module for company A rearranges b00 to b112 in accordance with the regulations of company A, and after performing a parity check or the like, acquires the product name, serial number, and the like.

  On the other hand, if it is not company A in step S10, it is then determined whether the manufacturer ID indicates company B (step S12), and if it is company B, a module for company B is activated (step S13). As in step S11, b00 to b112 are rearranged according to the regulations of company B, and after a parity check or the like, the product name, serial number, etc. are acquired.

  Similarly, if it is not B company in step S12, then C company, D company. . . Thus, the manufacturer IDs are checked for the number of registered manufacturers.

  In this embodiment, the AddOn lines for storing information for each manufacturer are fixed to 12 AddOn lines 4 to 15. However, the number of AddOn lines may be variable for each manufacturer.

  In the above embodiment, the parity bit is simply added to each of the manufacturer ID corresponding to the area 901 in FIG. 9 and the product name and serial number corresponding to the area 902 in FIG. However, the present invention is not limited to this, and each of the additional information corresponding to the area 901 and the area 902 may have an error correction code that can correct the error of the additional information. good.

  Thereby, even if there is an error in the analysis of the additional information, the operation of reading the phase difference again can be omitted.

  Furthermore, the additional information (manufacturer ID) in the area 901 is more than the additional information (product name, serial number, etc.) corresponding to the area 902, such as the possibility that the area 902 cannot be analyzed unless the additional information in the area 901 can be analyzed. If the degree of importance is considered high, the additional information in the area 901 is given an error correction code having a high error correction capability, and the area 902 is given an error correction code having a lower error correction capability than the area 901. You may do it.

  According to this, it becomes possible to analyze the important part of additional information reliably. Specifically, since the manufacturer ID can be analyzed with certainty, a method for analyzing the product name, production number, etc. can be determined thereafter.

  In the above embodiment, the method of adding the manufacturer ID to the area 901 and the method of adding the product name, the manufacturing number, etc. to the area 902 have been described as the same system. However, the present invention is not limited to this. This includes the case where the additional methods of additional information 901 and 902 are different.

  That is, in the above embodiment, the addition method of the additional information in the areas 901 and 902 is different by adding the manufacturer ID that can specify the addition method of the area 902 to the area 901 different from the area 902. However, if the analysis is performed in the order of the areas 901 and 902 as described above, there is an effect that all of the additional information can be sufficiently decoded.

  In the above embodiment, the additional information is simply added by the AddOn dot in which the original image is modulated to the highest density, but the present invention is not limited to this. For example, sufficient analysis can be performed even if a single AddOn dot is formed by combining a region where the density of the original image is + α and a region where the density is −α. In this case, since the density of the original image is stored, it is possible to maintain better image quality than in the above embodiment. Further, one AddOn dot may be configured by combining a region where the density of the original image is modulated to the highest density and a region where the density is modulated to the lowest density. According to this, the AddOn dot can be easily decoded regardless of the density of the original image.

(Modification)
Even if the present invention is applied as a part of a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it can be realized from a single device (for example, a copier, a printer, a facsimile machine). You may apply to one part of the apparatus which becomes.

  In addition, the present invention is not limited only to the apparatus and method for realizing the above-described embodiment, and software for realizing the above-described embodiment on a computer (CPU or MPU) in the system or apparatus. A case in which the above-described embodiment is realized by supplying a software program code and causing the system or apparatus computer to operate the various devices according to the program code is also included in the scope of the present invention.

  In this case, the program code of the software itself realizes the function of the above embodiment, and the program code itself and means for supplying the program code to the computer, specifically, the program code Is included in the scope of the present invention.

  As a storage medium for storing such a program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  The computer controls various devices according to only the supplied program code so that the functions of the above-described embodiments are realized, and the OS (operating system) on which the program code is running on the computer is also provided. Such program code is also included in the scope of the present invention even when the above embodiment is realized in cooperation with a system) or other application software.

  Further, after the supplied program code is stored in the memory of the function expansion board of the computer or the function expansion unit connected to the computer, the program code is stored in the function expansion board or function storage unit based on the instruction of the program code. The case where the above-described embodiment is realized by performing a part or all of the actual processing and the processing is included in the scope of the present invention.

The figure which shows an example of the image processing apparatus applied to this invention The figure showing a state of adding additional information to the input image The figure showing the state of the register that stores the tracking code (additional information) Block diagram of AddOn dot addition processing unit The figure explaining the expression method of the information by AddOn dot The figure showing the code which each AddOn line shows Diagram showing parity bits of manufacturer ID The figure which shows the procedure which decodes additional information from the image to which additional information was added. Conceptual diagram of additional information of manufacturer ID, product name and serial number

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Photosensitive drum 101 Charger 102 Transfer drum 103 Cleaner 1000 Image processing part

Claims (16)

The first additional information including the error correction code having the first error correction capability is added to the input image so that it is difficult to be recognized by human eyes, and the second error correction capability is different from the first error correction capability. Adding means for adding the second additional information including an error correction code having the following difficulty to human eyes:
An image processing apparatus comprising: an output unit that outputs an image to which predetermined additional information is added by the adding unit to an image forming unit.   The image processing apparatus according to claim 1, wherein the first additional information is information that can specify a method of adding the second additional information by the adding unit.   The image processing apparatus according to claim 1, wherein the first error correction capability is higher than the second error correction capability.   The image processing apparatus according to claim 1, wherein a method for adding the first additional information is different from a method for adding the second additional information.   The image processing apparatus according to claim 1, wherein a method for adding the first additional information and a method for adding the second additional information are the same.   The input image is a color image composed of a plurality of color planes, and the adding means adds the first and second additional information only to a part of the plurality of color planes. The image processing apparatus according to claim 1.   The image processing apparatus according to claim 1, wherein the first additional information is a manufacturer of the image treatment apparatus.   The image processing apparatus according to claim 1, wherein the second additional information is a model number or a product name of the image processing apparatus.   The image processing apparatus according to claim 1, wherein the second additional information is a machine number or a manufacturing number of the image processing apparatus.   The image processing apparatus according to claim 1, further comprising the image forming unit.   The image processing apparatus according to claim 1, wherein the first additional information is a pattern composed of a plurality of dots.   The image processing apparatus according to claim 1, wherein the second additional information is a pattern composed of a plurality of dots.   The image processing apparatus according to claim 1, wherein the additional information is periodically added to the input image.   2. The first additional information is added to a first area of the input image, and the second additional information is added to a second area different from the first area. An image processing apparatus according to 1. The first additional information including the error correction code having the first error correction capability is added to the input image so that it is difficult to be recognized by human eyes, and the second error correction capability is different from the first error correction capability. An additional step of adding the second additional information including the error correction code having
And an output step of outputting the image to which the predetermined additional information is added in the adding step to the image forming unit. The first additional information including the error correction code having the first error correction capability is added to the input image so that it is difficult to be recognized by human eyes, and the second error correction capability is different from the first error correction capability. An additional step of adding the second additional information including the error correction code having
A storage medium storing an image processing program in a readable state from a computer, the output step outputting to the image forming unit an image to which predetermined additional information is added in the adding step.

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