JP2007184880A - Image processor, and image processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor and an image processing system which have enhanced versatility by enabling information of an image mode to be imparted to image data without using a header or the like of the image data and can prevent deterioration in image quality of an output image when outputting stored image data to transfer paper or the like. <P>SOLUTION: The image processor performs: digital watermark information synthesis processing 121 for imparting information on an image mode used for performing processing by an RIP (Raster Image Processor) to image data to which image processing is applied by a printer correcting part; and correction processing for data format conversion for performing image correction of the image data on the basis of the digital watermark information when receiving via a network image data to which watermark information is imparted by the digital watermark information synthesis processing 121. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and an image processing system, and more particularly, to an image processing apparatus and an image processing system that can prevent image quality deterioration of an output image when image data is stored.

In recent years, a copying machine (image processing apparatus) that incorporates a scanner function, a printer function, a facsimile function, and the like in addition to a copy function and performs multi-function control has become widespread. Such a device can be easily connected to a network. Further, image data and information about the image data can be stored in a storage device such as an HDD in the device. Data stored in the storage device can be transmitted / received via a network or the like. On a network in which such a device is installed, for example, it is possible to output image data stored according to an instruction from a PC.
In recent years, color copiers have improved image processing technology and image forming technology, so that once an image has been captured by a scanner, etc. can be output easily, its copyright must be protected. There is a case where image processing for embedding information as digital watermark information is performed on an image. This technique is used as an image processing method for protecting copyrights and discriminating special manuscripts such as banknotes and securities.

For example, as a device for discriminating a special document, there is a method using a pattern matching method as disclosed in Patent Document 1. In this apparatus, it is determined whether or not a document is a specific copy-prohibited document based on the input image data and previously registered pattern data. At this time, the image data is already stored in the image storage device, and at this time, other related attribute data is also stored. Based on the attribute data, when a copy-prohibited document is to be copied, copying is prohibited, or a document that has been processed and copied can be easily distinguished from a document.
As an apparatus using digital watermark information, as shown in Patent Document 2, when predetermined digital watermark information is added to image data, image degradation processing based on the digital watermark information is performed as an image. An apparatus for protecting image data by applying to data has been proposed. Further, Patent Document 3 has a function of adding an electronic watermark information for specifying an operator and a device to an input image and a function of extracting the input image. A technique has been shown in which non-visible watermark data is left by performing additional processing on information, and forgery tracking is enabled to improve the effect of forgery prevention / counterfeit deterrence.
JP-A-2-83571 JP 2003-115992 A Japanese Patent Laid-Open No. 10-285381

However, the above-described conventional technique is a technique for limiting output and image quality, and handling information such as an operator, and intends to solve a security problem. For this reason, it has not been possible to meet the demand for maintaining and outputting the image quality at the first image formation without degrading the image quality of the stored image data. Also, for example, assuming that the image is output again based on the stored image data, if information such as the image mode can be extracted from the header of the stored image data, etc., it matches the image data. It is possible to output with the image quality, but if the information is not available from the beginning or if the information cannot be extracted, the optimum image mode cannot be set, so the output image is output with degraded image quality. There was a problem.
Therefore, the present invention has been made in consideration of the above-described circumstances, and improves versatility by allowing image mode information to be added to image data without using a header of the image data. An object of the present invention is to provide an image processing apparatus and an image processing system capable of preventing image quality deterioration of an output image when the accumulated image data is output to transfer paper or the like.

  In order to solve the above problems, the invention described in claim 1 is a device for performing a last image processing for printing information input from the outside, and a printer for performing image processing on image data generated by the device. Correction means; data storage means for storing information including image data subjected to image processing by the printer correction means; and image forming means for forming an image based on the image data generated by the printer correction means. In the image processing apparatus, digital watermark information synthesizing means for adding information about the image mode used when the last image processing is performed to image data subjected to image processing by the printer correcting means, and the digital watermark information synthesizing means When image data with watermark information is received via the network, Characterized by comprising an image correcting means for performing image correction on image data based on the electronic watermark information.

According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the digital watermark information is added when the image data is stored in the data storage unit, or the image data is stored in the data storage unit. An image processing apparatus capable of selecting whether to add the digital watermark information at the stage of transmitting image data to another image processing apparatus on the network without adding the digital watermark information when storing the data in To do.
According to a third aspect of the present invention, in the image processing apparatus according to the first or second aspect, an image processing apparatus that performs color correction as correction by the image correction unit is a main feature.
According to a fourth aspect of the present invention, an image processing system having the image processing apparatus according to any one of the first to third aspects and a PC on a network is a main feature.

  According to the present invention, when image mode information is added to image data, it is added to the image data as watermark information without using the header of the image data. Even when the image processing apparatus that has performed processing by last image processing (hereinafter referred to as RIP) and the image processing apparatus that performs image output are different, the image mode used at the time of processing by RIP in the image processing apparatus is converted into image data as watermark information. Since the image is corrected and output based on the watermark information on the receiving side and the image is output to the transfer paper, the image quality of the output image can be prevented from being deteriorated.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of an image processing apparatus according to the present invention together with a flow at the time of storing image data. The image processing apparatus has a function as an MFP (Multi Function Printer) such as a digital copying machine (image forming apparatus). FIG. 2 is a block diagram illustrating a configuration example of the scanner correction unit 2 of FIG.
This image processing apparatus is roughly divided into an engine unit and a printer controller unit. The engine unit includes a reading unit (scanner unit) 1, a scanner correction unit 2, a color / monochrome multi-value data fixed length compressor 3, an engine controller 4, a color / monochrome multi-value data fixed length decompressor 5, a printer correction unit 6 ( A printer correction unit), a GAVD (writing unit) 7, an image forming unit (image forming unit) 8, a FAX controller 9, an image recognition device 10, and the like. The printer controller unit includes a printer controller 11, a semiconductor memory 12, an HDD (hard disk device as data storage means) 13, a data format conversion device 14, a NIC (network interface controller) 15, an operation unit 20, and the like. Yes. The engine unit and the printer controller unit are connected by a general-purpose bus interface (hereinafter, “interface” is referred to as “I / F”) 16.

  The reading unit 1 of the engine unit is an image reading unit, and optically reads an image of a document set (placed) at a reading position (for example, on a contact glass) or a document passing through the reading position. At this time, R (red), G (green), and B (blue) color-separated light is photoelectrically converted and amplified, and an RGB image 8-bit image (which may be other than 8 bits) is an electrical image signal. The data is sent to the scanner correction unit 2 as data. The original for reading is set at the reading position of the reading unit 1 by the user, or the original on the original table is automatically fed one by one by an ADF (automatic document feeder) and set at the reading position. Or simply passes through the reading position by the ADF. Here, the image data read by the reading unit 1 is 8 bits for each color, but the present invention is not limited to this.

  As shown in FIG. 2, the scanner correction unit 2 includes a scanner gamma (γ) correction 101, a filter 102, a color correction 103, and a magnification / reduction 104 process. Image data obtained by sequentially performing scanner gamma (γ) correction processing, filter processing, color correction processing (color conversion from RGB system to CMYK system), and scaling process on the image data that has been processed. Is sent to the color / monochrome multi-value data fixed length compressor (fixed length irreversible compressor) 3. The color / monochrome multi-value data fixed length compressor 3 is a compression unit, and performs irreversible compression (encoding) on the image data sent from the scanner correction unit 2. That is, 8-bit color data (color signal) for each color of CMYK is converted into 2-bit (or other than 2 bits) color data for each color. Since the output unit of the color / monochrome multi-value data fixed length compressor 3 is connected to the general-purpose bus I / F 16, the CMYK image data after irreversible compression passes through the general-purpose bus I / F 16 to the printer controller unit. It is sent to the printer controller 11.

  The printer controller 11 uses a microcomputer including a CPU (Central Processing Unit), a ROM, and a RAM, and comprehensively controls the entire printer controller unit. The semiconductor memory 12 included in the printer controller 11 is independent for each color of CMYK, and can store (store) CMYK image data under the control of the printer controller 11. The HDD 13 is a large-capacity storage device, and can accumulate and store various data such as a large amount of image data, job history data, and various programs including a program according to the present invention. The HDD 13 and the semiconductor memory 12 correspond to image storage means. Further, instead of the HDD 13, another mass storage device such as an optical disk device can be used.

  Here, the image data stored in the semiconductor memory 12 is also stored in the HDD 13 as needed. This is to avoid rereading the same document again even when the paper is jammed during printing (printout) and printing does not end normally, or to perform electronic sorting that rearranges the image data of multiple documents. To do. In recent years, there are digital copying machines to which not only this but also a function of accumulating image data of a read original and re-outputting (reprinting or redistributing) when necessary is added. In this example, irreversible compression is applied to the CMYK image data. However, if the general-purpose bus I / F 16 has a sufficiently wide bandwidth and the storage capacity of the HDD 13 to be stored is large, the data is not compressed. May handle. This can prevent image degradation due to irreversible compression. At the time of copying, the CMYK image data (compressed data) in the HDD 13 is once expanded in the semiconductor memory 12 by the printer controller 11, and then passes through the general-purpose bus I / F 16 to fix the color / monochrome multi-value data fixed length of the engine unit. It is sent to the decompressor 5.

A color / monochrome multi-value data fixed length decompressor (fixed length irreversible decompressor) 5 in the engine unit is a decompressing unit that decompresses (decodes) image data (compressed data) sent from the printer controller unit. To do. That is, the CMYK 2-bit color data for each color is converted into 8-bit color data for each color. Then, the converted image data is sent to the printer correction unit 6. As shown in FIG. 3, the processing of the printer correction unit 6 includes color correction 109, printer gamma correction 110, and halftone processing 111. The color correction processing and printer gamma correction processing are followed by the image forming unit. The halftone processing is performed, and the image data subjected to the image processing is sent to the GAVD 7 for each color.
The GAVD 7 modulates and drives a semiconductor laser (laser diode) (not shown) based on the C image data sent from the printer correction unit 6 to emit a corresponding laser beam, and periodically uses a polygon mirror (rotating polygon mirror). A drum-shaped or belt-shaped photosensitive member (uniformly charged in advance by the charger of the image forming unit 8) in the main scanning direction is rotated in the sub-scanning direction by the laser beam deflected and focused by the scanning lens. An electrostatic latent image is formed by repeated scanning. Thereafter, the same processing as described above is performed on each of the M, Y, and K image data sequentially sent from the printer correction unit 6.

  The image forming unit 8 performs a known image forming process. For example, a charging device uniformly charges the surface of a photoconductor, and a C toner image is formed by adhering C toner to an electrostatic latent image corresponding to Y image data formed on the photoconductor by a C developing unit. Then, it is transferred onto a belt-shaped or drum-shaped intermediate transfer member by a primary transfer unit. Next, an M toner image is formed on the electrostatic latent image corresponding to the M image data formed on the photosensitive member by the M developing unit to form an M toner image, which is then transferred to the intermediate transfer member by the primary transfer unit. The toner image is transferred onto the C toner image. Thereafter, the Y and K developing units sequentially perform the same processing as described above to form a four-color superimposed toner image on the intermediate transfer member, and the four-color superimposed toner image is transferred from the paper feeding unit. After a batch transfer is performed on the fed paper (transfer paper) by the secondary transfer unit, the toner image on the paper is fused and fixed by the fixing unit, and the paper (copy) after the fixing process is transferred to the paper discharge unit. Eject paper. The order of image formation is not limited to CMYK.

  The engine controller 4 uses a microcomputer including a CPU, a ROM, and a RAM, and comprehensively controls the entire engine unit. The FAX controller 9 controls transmission / reception of FAX data (image data) to / from an image forming apparatus such as a FAX apparatus or another image processing apparatus having a FAX function via a public line. The data format converter 14 performs various processes such as resolution conversion and color space conversion, which will be described in detail later. The NIC 15 is a communication unit, and communicates with an external device such as a PC (Personal Computer) 30 (external PC) and a PC 31 (administrator PC) on a network such as a LAN (local area network). The operation unit 20 includes various operation buttons such as a copy button (copy key) and a display for displaying various information.

  The present image processing apparatus configured as described above applies to image data when output to transfer paper is performed in the image processing apparatus based on an image forming request from a PC (PC 30 or PC 31) on the network. In this case, the image mode information used at the time of processing by the RIP (Raster Image Processor) is added as electronic watermark information and stored in the HDD 13 and, if necessary, has the same function as the image processing apparatus on the network. The image data to which the digital watermark information is added can be transmitted to the image processing apparatus, and the image data can be transmitted to the PC on the network. The image processing apparatus can store the image data processed by the RIP in the HDD 13 without adding a digital watermark, and can add digital watermark information when transmitting the image data. It is possible to select whether to add digital watermark information or at the time of transmission. With respect to the image data transmitted in this manner, the other image processing apparatus on the receiving side can output the received image data to the transfer sheet based on the digital watermark information given thereto.

  The output operation to the transfer paper in the image processing apparatus based on the image forming request from the PC will be described in detail. First, the color space (RGB, sRGB, CMYK) on the PC by the printer driver depends on the image processing apparatus by color space conversion. To the device-dependent CMYK color space. The color image data converted to CMYK is subjected to halftone processing on the printer controller 11 (FIG. 1) and converted to low bit data of about 1 to 4 bits, and then processed by RIP. In the processing by RIP, processing for conversion into bitmap data is performed according to the resolution. The image data that has been processed by the RIP is sequentially compressed by a dedicated compressor and stored in the HDD 13. This is because the data size after processing by the RIP is large, and if it is stored in the memory without being compressed, a very large amount of memory is consumed. Note that the resolution at the time of image formation includes 300, 600, and 1200 dpi.

  Then, information on the image mode used by the RIP processing (selected by the user from modes such as general document, photo, DTP, and CAD) is added to the image data when stored in the HDD 13 as digital watermark information. . In this case, as described above, it is possible to select to add digital watermark information when transmitting image data. The digital watermarking is performed by a digital watermark synthesis process (digital watermark synthesis means) 121 in the data format conversion device 14 of FIG. When digital watermark information is added at the time of transmission, as shown in FIG. 4, the data format conversion device 14 performs block fixed length expansion processing 120 and digital watermark synthesis processing 121 and then transmits them. If digital watermark information has already been assigned at the time of storage, the data format conversion device 14 transmits the block fixed length expansion processing 120 as shown in FIG. In the image processing apparatus on the receiving side, digital watermark information is extracted. Information indicating in which image mode the image data was output is extracted through means (not shown) for extracting a digital watermark in the image recognition apparatus (FIG. 1). Next, based on the extracted digital watermark information, a data format conversion correction process 122 and an image format conversion process (in the example shown in the figure, a conversion process to JPEG format) 123 are performed in the data format conversion apparatus 14 as shown in FIG. After performing the above, output to transfer paper is performed. As a result, it is possible to prevent deterioration of the image quality of the output image. In this example, the digital watermark synthesizing means is provided in the data format conversion device 14, but the place where the digital watermark is added is not particularly limited here.

  Here, the data format conversion correction process 122 will be described. In this processing, for example, image processing as shown in FIG. 7 is performed. First, image data obtained by decompressing image data stored in a storage device such as the HDD 13 is input to a data format conversion correction process. The internal color space conversion process 124 converts the color space set when the image is distributed to the PC. For example, when the color space of the image data stored in the device is CMYK and the image data is distributed to the PC side in the TIFF format, the color space conversion process converts the CMYK space to the RGB space. In addition, even if the color space of the image data stored in the device is the same as the color space of the format, for example, both are RGB spaces, this color space conversion process performs optimum color correction when delivered to the PC side. To do. Next, in the resolution conversion process 125, for example, when the PC is requested to distribute data at a resolution of 200 dpi, the resolution conversion is performed if the image data stored in the device is 600 dpi. In the case of this example, the resolution is converted to 1/3 of the original image. Thereafter, a filtering process is performed in the spatial filter process 126. In this spatial filter processing, for example, smoothing processing for smoothing image data, edge enhancement processing for performing processing according to the image frequency such as image edges, and the like can be performed.

  Specifically, in the smoothing process, moire is suppressed in the image data, and in edge enhancement, the edge is enhanced in order to correct deterioration of frequency characteristics when the image is read by the reading device. After performing this spatial filter processing 126, the γ correction processing 127 adjusts the density γ of the image data. For example, if the density is for characters, processing is performed so as to obtain a γ characteristic that is raised to the high density side. After this γ correction, halftone processing 128 suitable for the output image format is performed. For example, when converting to a TIFF format such as FAX data, binarization processing or error diffusion processing is performed here. It should be noted that the image correction parameters in the data format conversion correction are simply set in the image mode set from the PC, for example, when it is normally received as image data on the PC side or for the purpose of OCR recognition. There are various image formats such as JPEG, TIFF, binary TIFF, and BMP. In accordance with these settings, the parameters for image correction for data format conversion correction are set according to their suitability.

  By the way, the reason for setting the option that the digital watermark information is added at the time of transmission is because it is assumed that the stored image data is to be edited after the processing by RIP. For example, when a general manuscript is assumed except for special manuscripts such as banknotes and securities, considering that image data is once edited by an editing means such as a PC and then stored again. Yes. Note that in the image data requested to be transferred to the transfer paper, the resolution and color space of the print output data stored in the HDD 13 is obtained in order to acquire, view, and process the data stored in the HDD 13 again with the PC. It must be viewable on the PC or be in the format required by the PC (match). As for the processing order, it is necessary to perform resolution conversion and color space conversion by performing “decompression → multi-value conversion → dpi conversion → color space conversion → compression” in the data format conversion device 14 (FIG. 1). By performing such processing, it is possible to acquire, browse, and process the data requested by the printer output stored in the HDD 13 again with the PC.

  Next, a case where image data stored in the HDD 13 is transferred to a PC (PC 30 or PC 31) via a network or the like will be described. First, in FIG. 8, the image data stored in the HDD 13 enters the data format conversion device 14 through the general-purpose bus. Since the image data first stored in the HDD 13 is stored in a compressed state as described above, it is expanded by the block fixed length expansion processing 120 as shown in FIG. Thereafter, image correction is performed in the data format conversion correction process 122, and conversion to an image format conversion process (JPEG format in the example in the figure) 123 desired to be received by the PC is performed. Then, as shown in FIG. 8, it is delivered to the PC through the NIC 15 via the network. In this example, the image is converted into the JPEG format. However, the image format can be converted into other general-purpose formats such as TIFF format and BMP format. But no problem.

  As described above, in the image processing apparatus as the best mode for carrying out the present invention, when image mode information is added to image data, image data is used as digital watermark information without using a header of the image data. As a result, the versatility of handling image mode information is improved, and even when the image processing apparatus that has performed the processing by RIP and the image processing apparatus that performs the image output are different, they are used at the time of processing by the RIP in the image processing apparatus. The image mode is added to the image data as digital watermark information and transmitted, and the image is corrected on the receiving side based on the digital watermark information and the image is output onto the transfer paper, thereby preventing deterioration of the image quality of the output image. Can do.

The instruction to output the image data to the transfer paper may be issued from a PC connected to the network or from an operation panel on another image processing apparatus. In that case, you may display thumbnail images such as thumbnails so that the contents of the image data can be visually understood, or display bibliographic information such as the image data name and date the data was acquired. May be. By displaying such information, the operation can be improved.
Further, when the digital watermark is recognized by the image recognition device of the image processing device, for example, bibliographic information such as model information of the image processing device is also stored in the image information stored as image data in the HDD 13. The administrator can confirm the information. As a result, the administrator can grasp from which image processing apparatus or image processing system the image data has been transmitted to the external PC via the network, and can also be used from the viewpoint of security. Furthermore, for special manuscripts such as banknotes and securities, output itself can be prohibited by the information of the electronic watermark, or conversely, processing that degrades image quality can be added.
In this embodiment, the method of outputting image data using digital watermark has been described. However, output can be performed by selecting whether to use digital watermark information or header information. It is also possible to use it.

It is a block diagram which shows the structural example of the image processing apparatus by this invention with the flow at the time of accumulation | storage of image data. It is a block diagram which shows the processing structure of the scanner correction | amendment part 2 of FIG. FIG. 6 is a block diagram showing a processing configuration of a printer correction unit 6. It is a flowchart which shows the processing structure (digital watermarking at the time of transmission) of the data format conversion apparatus 14 of a transmission side. It is a flowchart which shows the processing structure (The digital watermark is already provided at the time of accumulation | storage) of the data format conversion apparatus 14 of a transmission side. It is a flowchart which shows the process structure (at the time of output to a transfer paper) of the data format conversion apparatus 14 on the receiving side. It is a flowchart which shows the processing structure of the correction | amendment 122 for data format conversion. It is a block diagram which shows the structural example of the image processing apparatus by this invention with the flow at the time of transmission of image data. It is a flowchart which shows the processing structure (at the time of transmission to PC) of the data format conversion apparatus 14 of a transmission side.

Explanation of symbols

  1 reading unit, 2 scanner correction unit, 3 color / monochrome multi-value data fixed length compressor, 4 engine controller, 5 color / monochrome multi-value data fixed length decompressor, 6 printer correction unit, 7 GAVD, 8 image forming unit, 9 FAX controller, 10 Image recognition device, 11 Printer controller, 12 Semiconductor memory, 13 HDD, 14 Data format conversion device, 15 NIC, 16 General-purpose bus interface, 20 Operation unit, 30, 31 PC, 101 Scanner gamma (γ) correction , 102 filter, 103 color correction, 104 scaling, 109 color correction, 110 printer gamma correction, 111, 128 halftone processing, 120 block fixed length expansion processing, 121 digital watermark composition processing, 122 data format conversion correction, 123 images Format conversion processing , 124 color space conversion processing, 125 resolution conversion processing, 126 a spatial filter process, 127 gamma correction

Claims (4)

An apparatus for performing last image processing for printing information input from the outside, printer correction means for performing image processing on image data generated by the apparatus, and
Data storage means for storing information including image data subjected to image processing by the printer correction means;
In an image processing apparatus having image forming means for forming an image based on image data generated by the printer correcting means,
Digital watermark information synthesizing means for giving information about the image mode used when the last image processing was performed to image data subjected to image processing by the printer correction means;
Image correction means for performing image correction on the image data based on the digital watermark information when image data to which the digital watermark information is added by the digital watermark information combining means is received via a network. A featured image processing apparatus. The image processing apparatus according to claim 1.
When the image data is stored in the data storage means, the digital watermark information is added, or when the image data is stored in the data storage means, the image data is not added to the network other than the network. An image processing apparatus characterized in that it can be selected whether to give the digital watermark information at the stage of transmission to the image processing apparatus. The image processing apparatus according to claim 1 or 2,
An image processing apparatus that performs color correction as correction by the image correction unit.   An image processing system comprising the image processing apparatus according to claim 1 and a PC on a network.

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