JP2007059971A - Image processing system, image processing method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing system capable of appropriately extracting data to be used for correction processing after reducing waste of paper. <P>SOLUTION: An image processing apparatus 20 previously stores correction information of an image. Upon receiving an input image, the apparatus 20 performs color conversion processing to convert the pixel value of each of pixels for a correction target position while referring to the correction information. Image data are controlled by an image formation control apparatus 21 and an image subjected to the correction processing is formed on a recording paper 32. An image detecting sensor 22 reads an image from the recording paper 32 and outputs the read image to the apparatus 20. The apparatus 20 detects a correction region from the read image to determine the region, acquires correction information used for correcting colors or density from the determined region, and updates the stored correction information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming system such as a printer, a facsimile machine, and a copying machine.

Conventionally, in an image forming apparatus, density unevenness may occur in the surface.
Patent Document 1 discloses an image forming apparatus that outputs a test pattern, reads density unevenness generated in the axial direction of the photosensitive drum, and corrects a digital image signal.

  However, when the test pattern is output and corrected, the image forming apparatus interrupts the normal printing operation, which causes downtime of the apparatus. Further, the paper used for test pattern output is unnecessary for the user.

JP-A-6-3911

  The present invention has been made from the above-described background, and an object of the present invention is to provide an image processing system that can appropriately extract data used for correction processing while reducing paper waste.

  In order to achieve the above object, an image processing system according to the present invention includes a correction information storage unit that stores correction information of an image, an image reception unit that receives an input image, and a correction stored by the correction information storage unit. An area for obtaining correction information based on the correction means for correcting the input image received by the image receiving means based on the information, the input image received by the image receiving means, and the read read image An area detecting means for detecting the area, an area determining means for determining an area detected by the area detecting means based on the area and a peripheral area of the area, and an area determined by the area determining means. Correction information updating means for updating the correction information stored in the correction information storage means based on the image portion included in the input image and the read image Having.

Preferably, the correction information storage means stores image unevenness information.
Preferably, the region determination unit sets at least a part of an image portion including the region detected by the region detection unit and a peripheral region of the region as a correction information acquisition region.
Preferably, the area determination unit selects an image part whose pixel values are substantially uniform in the read image from among the image parts including the area detected by the area detection unit and the peripheral area of the area. And

Preferably, the area determination unit deletes, from the correction information acquisition area, an image portion where a defect has occurred among the areas detected by the area detection unit.
Preferably, in the image portion deleted by the area determination unit, the defect is a defect based on the structure of the input image.

  An image processing method according to the present invention stores image correction information, receives an input image, corrects the received input image based on the stored correction information, and An area for acquiring correction information is detected based on the read image that has been read, and the detected area is determined based on the area and a peripheral area of the area. Then, the stored correction information is updated based on the image portion included in the input image and the read image.

  Further, the program according to the present invention is based on the correction information storing step for storing the correction information of the image, the image receiving step for receiving the input image, and the stored correction information in the image processing system including the computer. A correction step for correcting the received input image, a region detection step for detecting a region for acquiring correction information based on the received input image and the read image that has been read, and the detected region Is determined based on the region and the peripheral region of the region, and the stored correction information based on the determined region and the image portion included in the input image and the read image The correction information update step for updating the image processing system is executed by the computer of the image processing system.

  According to the image processing system of the present invention, it is possible to appropriately extract data used for correction processing while reducing paper waste.

FIG. 1 is a diagram showing an image processing system according to the present invention centering on a tandem type image forming apparatus 10.
As shown in FIG. 1, the image forming apparatus 10 includes an image reading unit 12, an image forming unit 14, an intermediate transfer belt 16, a paper tray 17, a paper transport path 18, a fixing device 19, an image processing device 20, and an image forming control device. 21, an image detection sensor 22 and a user interface (UI) device 23. The image forming apparatus 10 has a function as a full-color copying machine using the image reading unit 12 and a function as a facsimile in addition to a printer function for printing image data received from a personal computer (not shown). It may be a multifunction machine.

  First, the outline of the image forming apparatus 10 will be described. In the upper part of the image forming apparatus 10, an image reading unit 12, an image processing apparatus 20, and an image forming control apparatus 21 are arranged. The image reading unit 12 reads an image displayed on the document 30 and outputs it to the image processing apparatus 20. The image processing apparatus 20 performs color conversion processing and correction processing described later on image data input from the image reading unit 12 or image data input from a personal computer or the like via a network line such as a LAN. Image processing is performed and output to the image formation control device 21. The image forming control device 21 controls the image forming unit 14 based on the image data subjected to image processing. Note that the image formation control device 21 may be included in the image processing device 20 as a part of the image processing device 20.

  A UI device 23 such as a touch panel is provided on the upper surface of the image forming apparatus 10. The UI device 23 displays control information and instruction information of the image forming apparatus 10 and accepts input by the user such as instruction information. That is, the user can operate the image forming apparatus 10 via the UI device 23. Note that the UI device 23 may accept only an input such as a switch, may perform only an output such as a display, or may be a combination of these.

  Below the image reading unit 12, a plurality of image forming units 14 are arranged corresponding to the colors constituting the color image. In this example, the first image forming unit 14K, the second image forming unit 14Y, and the third image forming corresponding to each color of black (K), yellow (Y), magenta (M), and cyan (C). The unit 14M and the fourth image forming unit 14C are arranged horizontally along the intermediate transfer belt 16 with a certain interval. The intermediate transfer belt 16 rotates as an intermediate transfer member in the direction of an arrow A in the figure, and these four image forming units 14K, 14Y, 14M, and 14C are configured based on the image data input from the image processing apparatus 20. The toner images are sequentially formed and transferred (primary transfer) to the intermediate transfer belt 16 at a timing at which the plurality of toner images are superimposed on each other. The order of the colors of the image forming units 14K, 14Y, 14M, and 14C is not limited to the order of black (K), yellow (Y), magenta (M), and cyan (C). ), Magenta (M), cyan (C), black (K), and the like.

  The sheet conveyance path 18 is disposed below the intermediate transfer belt 16. The recording paper 32 supplied from the paper tray 17 is transported on the paper transport path 18, and the toner images of each color transferred onto the intermediate transfer belt 16 are collectively transferred (secondary transfer). The transferred toner image is fixed by the fixing device 19 and discharged to the outside along the arrow B.

Next, each configuration of the image forming apparatus 10 will be described in detail.
As shown in FIG. 1, the image reading unit 12 includes a platen glass 124 on which a document 30 is placed, a platen cover 122 that presses the document 30 onto the platen glass 124, and a document 30 placed on the platen glass 124. And an image reading unit 130 for reading an image. The image reading unit 130 illuminates the original 30 placed on the platen glass 124 with a light source 132, and displays a reflected light image from the original 30 as a full rate mirror 134, a first half rate mirror 135, and a second half half. Scanning exposure is performed on an image reading element 138 made of a CCD or the like through a reduction optical system including a rate mirror 136 and an imaging lens 137, and the color material reflected light image of the document 30 is transferred to predetermined dots by the image reading element 138. It is configured to read at a density (for example, 16 dots / mm).

  The image processing device 20 performs predetermined image processing such as color conversion on image data read by the image reading unit 12 or image data input via a network line. The color material reflected light image of the document 30 read by the image reading unit 12 is, for example, document reflectance data of three colors of red (R), green (G), and blue (B). By the image processing by 20, the original color material gradation data of four colors of yellow (Y), magenta (M), cyan (C), and black (K) is converted.

  The image formation control device 21 generates a pulse signal according to the image data (YMCK) input from the image processing device 20 and outputs the pulse signal to the optical scanning device 140. More specifically, the image formation control device 21 performs a first optical scanning device 140K, a second optical scanning device 140Y, a third optical scanning device 140M, and a fourth optical scanning, which will be described later, based on the image data. A pulse signal is output to the device 140C to form an image.

The first image forming unit 14K, the second image forming unit 14Y, the third image forming unit 14M, and the fourth image forming unit 14C are arranged and formed in parallel at a certain interval in the horizontal direction. The configuration is almost the same except that the color of the image is different. Accordingly, the first image forming unit 14K will be described below. The configuration of each image forming unit 14 is distinguished by adding K, Y, M, or C.
The image forming unit 14K forms an electrostatic latent image by an optical scanning device 140K that scans a laser beam in accordance with image data input from the image processing device 20, and a laser beam scanned by the optical scanning device 140K. And an image forming apparatus 150K.

  The optical scanning device 140K modulates the semiconductor laser 142K according to the black (K) image data, and emits the laser light LB (K) from the semiconductor laser 142K according to the image data. The laser beam LB (K) emitted from the semiconductor laser 142K is applied to the rotary polygon mirror 146K via the first reflection mirror 143K and the second reflection mirror 144K, and is deflected and scanned by the rotation polygon mirror 146K. The light is irradiated onto the photosensitive drum 152K of the image forming apparatus 150K through the second reflecting mirror 144K, the third reflecting mirror 148K, and the fourth reflecting mirror 149K.

The image forming apparatus 150K includes a photosensitive drum 152K as an image carrier that rotates at a predetermined rotational speed in the direction of arrow A, and primary charging as a charging unit that uniformly charges the surface of the photosensitive drum 152K. And a developing device 156K for developing the electrostatic latent image formed on the photosensitive drum 154K, and a cleaning device 158K. The photosensitive drum 152K is uniformly charged by the scorotron 154K, and an electrostatic latent image is formed by the laser beam LB (K) irradiated by the optical scanning device 140K. The electrostatic latent image formed on the photosensitive drum 152K is developed with black (K) toner by the developing device 156K and transferred to the intermediate transfer belt 16. Residual toner, paper dust, and the like adhering to the photosensitive drum 152K after the toner image transfer process are removed by the cleaning device 158K.
The other image forming units 14Y, 14M, and 14C also form yellow (Y), magenta (M), and cyan (C) toner images in the same manner as described above, and intermediately transfer the formed toner images of the respective colors. Transfer to belt 16.

  The intermediate transfer belt 16 has a constant tension between the drive roll 164, the first idle roll 165, the steering roll 166, the second idle roll 167, the backup roll 168, and the third idle roll 169. The drive roll 164 is rotationally driven by a drive motor (not shown), and is circulated at a predetermined speed in the direction of arrow A. The intermediate transfer belt 16 is formed into an endless belt shape by, for example, forming a flexible synthetic resin film such as polyimide in a band shape and connecting both ends of the synthetic resin film formed in the band shape by welding or the like. It has been done.

  Further, the intermediate transfer belt 16 includes a first primary transfer roll 162K, a second primary transfer roll 162Y, a third primary transfer roll 162M, and a position facing the image forming units 14K, 14Y, 14M, and 14C, respectively. A fourth primary transfer roll 162C is provided, and the toner images of the respective colors formed on the photosensitive drums 152K, 152Y, 152M, and 152C are transferred onto the intermediate transfer belt 16 in a multiple manner by these primary transfer rolls 162. The The residual toner adhering to the intermediate transfer belt 16 is removed by a cleaning blade or brush of a belt cleaning device 189 provided downstream of the secondary transfer position.

In the paper transport path 18, a paper feed roller 180 for taking out the recording paper 32 from the paper tray 17, a first roller pair 181, a second roller pair 182 and a third roller pair 183 for paper transport, and a recording paper A registration roll 184 is provided that conveys 32 to the secondary transfer position at a predetermined timing.
In addition, a secondary transfer roll 185 that is in pressure contact with the backup roll 168 is disposed at the secondary transfer position on the paper transport path 18, and each color toner image transferred onto the intermediate transfer belt 16 is Secondary transfer is performed on the recording paper 32 by the pressing force and electrostatic force of the secondary transfer roll 185. The recording paper 32 onto which the toner image of each color is transferred is conveyed to the fixing device 19 by the first conveyance belt 186 and the second conveyance belt 187.
The fixing device 19 melts and fixes the toner to the recording paper 32 by performing heat treatment and pressure treatment on the recording paper 32 to which the toner images of the respective colors are transferred.

  An image detection sensor 22 is provided in the paper transport path 18. The image detection sensor 22 reads an image from the recording paper 32 conveyed along the paper conveyance path 18 and measures the feature amount of the image. The feature quantity measured by the image detection sensor 22 is color data such as the density, saturation, hue, and color distribution of each color, for example. The image detection sensor 22 outputs data relating to the read image (read image) to the image processing device 20.

FIG. 2 is a block diagram illustrating a functional configuration of the image processing apparatus 20.
As shown in FIG. 2, the image processing apparatus 20 includes an input image receiving unit 200, a color space converting unit 202, a correcting unit 204, a data output unit 206, a read image receiving unit 208, an area detecting unit 210, an area determining unit 212, The correction information update unit 214 and the correction information storage unit 220 are included, and the region detection unit 210 includes an input image analysis unit 216 and a difference detection unit 218.
Each of the above-described components included in the image processing apparatus 20 may be realized by software such as a CPU, a memory, and a program, or may be realized by hardware such as an ASIC. Further, the image processing apparatus 20 may be included not only in the image forming apparatus 10 but also in a personal computer, for example.

In the image processing apparatus 20, the input image receiving unit 200 receives an input image from a user's personal computer or the like and outputs the input image to the color space conversion unit 202. The input image data is, for example, an image that is represented by 8 bits for each of RGB and belongs to the sRGB space.
When input image data is not stored in the image processing apparatus 20, the input image receiving unit 200 can receive an input image from a personal computer or the like at an arbitrary timing.

  The color space conversion unit 202 converts the input image (RGB) into a CIELAB (L *, a *, b *) color space (or CIEXYZ) that is a colorimetric value, using a predetermined profile (color reproduction characteristics). . In addition, the color space conversion unit 202 converts the converted CIELAB color space image data into image data in the color system YMCK color space suitable for the printing process by using the profile, and the correction unit 204, area detection Output to the unit 210 and the correction information update unit 214. Here, the profile is information indicating the color reproduction characteristics of the image, and is, for example, an ICC profile. Note that the color space conversion unit 202 may convert the input RGB color space image into YMCK color space image data using a pre-stored DLUT (color conversion table).

  The correction unit 204 corrects the input image data to a gradation suitable for the printing process, and the input received by the input image reception unit 200 based on correction information stored in a correction information storage unit 220 described later. The image is corrected and output to the data output unit 206. More specifically, the correction unit 204 converts the pixel value of each pixel with reference to correction information related to color, density, and the like stored in the correction information storage unit 220. For example, the correction unit 204 refers to the correction information and performs uneven correction processing on the image data.

  The data output unit 206 outputs the image data in the YMCK color space input from the correction unit 204 to the image formation control device 21. Since the pixel value of the image data is converted by the correction unit 204, the image formation control device 21 controls the exposure light amount to the photosensitive drum 152 so as to be suitable for unevenness correction. The data output unit 206 may output the input image data and the corrected image data to a memory for storing image data.

  The area detection unit 210 is an image area suitable for detecting correction information (correction) based on an input image input from the color space conversion unit 202 and a read image input from a read image reception unit 208 described later. Area). Here, the read image is an image read by the image detection sensor 22, the image reading unit 12, or an external scanner.

  More specifically, in the region detection unit 210, the input image analysis unit 216 analyzes the input image and specifies an image portion with uniform data (image-smooth portion) in the input image. The input image analysis unit 216 analyzes the input image, generates a difference image between the input image and a low frequency image obtained by removing a high frequency component from the input image, and specifies a uniform image portion of the data in the input image. Further, the input image analysis unit 216 sets a threshold value, determines whether or not the image portion is larger than the threshold value, and selects an image portion that is equal to or larger than a predetermined range among the image portions as a correction candidate. This is an area.

  Note that the input image analysis unit 216 may analyze the input image in the time domain, obtain a variance value of pixel values in the peripheral area of the pixel of interest, and specify an image portion with uniform data in the input image. For example, the input image analysis unit 216 calculates a variance value using a 3 × 3 pixel matrix including the target pixel, compares the calculated variance value with a predetermined threshold value, and obtains an image portion with uniform data. It is determined whether or not.

The difference detection unit 218 detects a difference between the input image and the read image with respect to the pixels included in the correction candidate area, and sets an area having a large difference as a correction area.
The area detection unit 210 outputs the correction area detected by the difference detection unit 218 to the area determination unit 212.

The correction information is desirably extracted from a uniform color area for correction processing, particularly unevenness correction processing. Even when the image in the extracted area is uniform, an image close to the area may affect the color and density of the area.
The region determination unit 212 determines the correction region detected by the region detection unit 210 based on the region and the peripheral region of the region, and outputs the determination result to the correction information update unit 214. The determination process by the area determination unit 212 will be described in detail later.

  The read image reception unit 208 receives read image data input from the image detection sensor 22, the image reading unit 12, or an external scanner, and outputs the read image data to the region detection unit 210 and the correction information update unit 214. The read image receiving unit 208 outputs the read image data as data in the YMCK color space. For example, when the read image reception unit 208 receives a read image expressed in a device-independent color space such as the CIELAB color space or the CIEXYZ color space, the read image reception unit 208 converts the data into YMCK color space data and outputs the converted data. . Note that the read image receiving unit 208 is not limited to the YMCK color space, and may be converted into data of another color space and output.

  The correction information update unit 214 updates the correction information stored in the correction information storage unit 220 based on the image portion included in the input image and the read image that is the region determined by the region determination unit 212. More specifically, in the correction information acquisition area, the correction information update unit 214 inputs the input image (YMCK data) input from the color space conversion unit 202 and the read image (YMCK data) input from the read image reception unit 208. ) Is detected and stored in the correction information storage unit 220 as correction information for the image portion. The stored correction information is used by the correction unit 204 in subsequent image processing.

  The correction information storage unit 220 stores the correction information acquired and stored by the correction information update unit 214. In particular, the correction information storage unit 220 stores image unevenness information. The correction information storage unit 220 is realized by a recording device (not shown) such as an HDD, or a memory. The stored correction information is used for correction processing by the correction unit 204.

FIG. 3 is a diagram for explaining determination processing by the region determination unit 212.
FIG. 3A illustrates a defect generated in the read image based on the structure of the input image. In particular, a portion surrounded by a solid line is a developing roll of a developing device in a two-component developing system using a carrier and toner. This is a defect in which the density at the rear end of the patch on the white ground (originally the same density) generated by the difference in peripheral speed between the photosensitive member and the photosensitive member is reduced. This decrease in density does not occur in any image. As illustrated in FIG. 3B, there is a case where the density does not decrease in the portion surrounded by the solid line.

  Therefore, when the correction information update unit 214 detects density unevenness in the patch rear end region based on the read image of FIG. 3A and updates the correction information, the image of FIG. 3B is input. In this case, the image processing apparatus 20 performs correction processing so as to generate unevenness using the updated correction information.

  Therefore, the region determination unit 212 outputs at least a part of the image portion including the region detected by the region detection unit 210 and the peripheral region of the region to the correction information update unit 214 as a correction information acquisition region. To do. In this example, the area determination unit 212 deletes an image part (a part surrounded by a solid line) in which a defect has occurred from the area detected by the area detection unit 210 from the correction information acquisition area. Of the image portion including the region detected by the detection unit 210 and the peripheral region of the region, an image portion having substantially uniform pixel values in the read image is set as a correction information acquisition region.

  The region determination unit 212 stores in advance a determination criterion that “the density of the rear end of the patch on the white ground becomes light”, and determines the region detected by the region detection unit 210 using this determination criterion. Note that the region determination unit 212 stores a plurality of determination criteria, and these determination criteria may be updated at an arbitrary timing.

FIG. 4 is a diagram illustrating patches included in a halftone image region and defects caused by the image structure.
As illustrated in FIG. 4A, when a patch having a higher density is included in the halftone image area, a defect may occur in the halftone area adjacent to the rear end of the patch. This defect is a defect based on the structure of the input image and relates to a phenomenon in which the density of the halftone area adjacent to the rear end of the patch is lowered. The area determination unit 212 stores information indicating that an image part in which a defect based on the image structure has occurred is deleted from the correction information acquisition area.

  FIG. 4B illustrates a case where the defect is caused by the transfer in which the density of the halftone area around the high density patch is lowered. Such a decrease in density often occurs under the image structure. For this reason, the area determination unit 212 also stores information indicating that an image part in which a defect based on the image structure has occurred is deleted from the correction information acquisition area.

  Further, the defects illustrated in FIGS. 4A and 4B are based on the image structure, and thus do not occur in the image structure as shown in FIG. In the image data shown in FIG. 4C, since the area determination unit 212 uses the entire halftone image area as the correction information acquisition area, the correction information update unit 214 performs correction information from the entire halftone image area. Is detected.

FIG. 5 is a diagram illustrating another determination process performed by the region determination unit 212.
As shown in FIG. 5A, the defect may occur at the rear end of the white ground patch. When this area is recognized as a patch, as shown in FIG. 5B, the density reduction in the area is recognized as the density reduction of the entire image, and correction information for increasing the density is acquired. For this reason, the area determination unit 212 has a determination criterion that does not recognize the rear end portion of the patch as a patch in such an image structure.
As described above, the region determination unit 212 deletes the defect based on the image structure from the correction information acquisition region according to the determination criterion stored in advance.

FIG. 6 is a flowchart showing the operation (S10) of the image processing system centered on the image forming apparatus 10.
As shown in FIG. 6, in step 100 (S100), the user makes a print request via a personal computer or the like. When input image data is input, the input image receiving unit 200 acquires the input image data via a network, and receives the received image data (for example, 8 bits for each of RGB) to the color space conversion unit 202. Output.

  In step 102 (S102), the color space conversion unit 202 uses the profile to color-convert input image data in the RGB color space into the CIELAB color space, performs predetermined image processing, and then uses a different profile. The converted CIELAB color space data is color-converted into YMCK color space image data depending on the output device. The color space conversion unit 202 may color-convert input image data in the RGB color space into image data in the YMCK color space using a color conversion table. The color space conversion unit 202 outputs the image data whose color space has been converted to the correction unit 204, the region detection unit 210, and the correction information update unit 214.

In step 104 (S104), the correction unit 204 refers to the correction information relating to the color and density stored in the correction information storage unit 220, and if there is a color signal that is the correction target for the correction target position. The pixel value of each pixel at the position is converted.
In step 106 (S106), the data output unit 206 outputs the image data input from the correction unit 204 to the image formation control device 21. The image forming control device 21 controls the image forming unit 14 based on the image data. For this reason, the amount of exposure light to the photosensitive drum 152 is controlled, and an image subjected to correction processing is formed on the recording paper 32.

  In step 108 (S 108), the image detection sensor 22 reads an image from the recording paper 32 that is transported through the paper transport path 18 and outputs the read image data to the image processing device 20. In the image processing apparatus 20, the read image receiving unit 208 receives read image data input from the image detection sensor 22 and outputs the read image data to the region detection unit 210 and the correction information update unit 214.

In step 110 (S110), the input image analysis unit 216 of the region detection unit 210 analyzes the input image input from the color space conversion unit 202, identifies an image portion with uniform data in the input image, and outputs the image. An image portion within a predetermined range is detected from the portion.
In step 112 (S112), the difference detection unit 218 detects a difference between the input image and the read image input from the read image reception unit 208 in the area detected by the input image analysis unit 216, and the difference is large. The region is a region from which correction information is acquired.

In step 114 (S114), the region determination unit 212 determines the correction region detected by the region detection unit 210 and the peripheral region of the region based on a predetermined determination criterion. For example, the region determination unit 212 deletes an image portion including a defect caused by the image structure included in the determination criterion from the correction information acquisition region. The area determination unit 212 outputs the area determined as the correction information acquisition area to the correction information update unit 214.
In step 116 (S116), the correction information update unit 214 detects a color and density shift based on the input image and the read image in the correction information acquisition region, and the correction information storage unit as correction information in the image portion. 220.

  As described above, the image processing system according to the present invention stores image correction information, receives an input image, corrects the input image based on the correction information, and corrects the correction information based on the input image and the read image. The region for acquiring the image is detected, the region is determined based on the region and the peripheral region of the region, and the correction information is updated based on the determined region and the image portion included in the input image and the read image Therefore, it is possible to appropriately extract data used for the correction process while reducing paper waste, and to reduce downtime of the image forming apparatus 10.

Further, the image processing system according to the present invention deletes an image portion in which a defect based on the structure of the input image has occurred from the detected image portion, so that inappropriate correction information is acquired. Can be prevented.
In the present embodiment, the correction information is used for correcting the color and density in the image processing apparatus 20, but is used for controlling the amount of exposure light to the photosensitive drum 152 in the image forming control apparatus 21. May be.

1 is a diagram showing an image processing system according to the present invention centering on a tandem type image forming apparatus 10. FIG. 3 is a block diagram illustrating a functional configuration of the image processing apparatus 20. FIG. It is a figure explaining the determination process by the area | region determination part. It is a figure which illustrates the defect contained in the patch contained in the image area of a halftone, and this image structure. It is a figure explaining the other determination processing by the area | region determination part 212. FIG. 4 is a flowchart showing an operation (S10) of the image processing system centered on the image forming apparatus 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image reading unit 14 Image forming unit 18 Paper conveyance path 20 Image processing apparatus 21 Image formation control apparatus 22 Image detection sensor 23 UI apparatus 32 Recording paper 200 Input image reception part 202 Color space conversion part 204 Correction part 206 Data Output unit 208 Read image reception unit 210 Region detection unit 212 Region determination unit 214 Correction information update unit 216 Input image analysis unit 218 Difference detection unit 220 Correction information storage unit

Claims (8)

Correction information storage means for storing image correction information;
Image receiving means for receiving an input image;
Correcting means for correcting the input image received by the image receiving means based on the correction information stored by the correction information storage means;
Area detecting means for detecting an area for acquiring correction information based on the input image received by the image receiving means and the read read image;
Area determination means for determining the area detected by the area detection means based on the area and the surrounding area of the area;
Correction information updating means for updating correction information stored in the correction information storage means on the basis of an image portion included in the input image and the read image that is an area determined by the area determination means. system. The image processing system according to claim 1, wherein the correction information storage unit stores unevenness information of an image. The image processing system according to claim 1, wherein the area determination unit sets at least a part of an image portion including the area detected by the area detection unit and a peripheral area of the area as a correction information acquisition area. . The region determination unit uses, as a correction information acquisition region, an image portion in which a pixel value is substantially uniform in a read image among image portions including the region detected by the region detection unit and a peripheral region of the region. 4. The image processing system according to 3. The image processing system according to claim 3, wherein the region determination unit deletes, from the correction information acquisition region, an image portion where a defect has occurred among the regions detected by the region detection unit. The image processing system according to claim 5, wherein in the image portion deleted by the region determination unit, the defect is a defect based on a structure of an input image. Stores image correction information,
Accept input images,
Correcting the accepted input image based on the stored correction information;
Based on the received input image and the read image that has been read, a region for obtaining correction information is detected,
Determining the detected area based on the area and the surrounding area of the area;
An image processing method for updating the stored correction information based on an image portion included in an input image and a read image in the determined area. In an image processing system including a computer,
A correction information storing step for storing image correction information;
An image receiving step for receiving an input image;
A correction step of correcting the received input image based on the stored correction information;
An area detecting step for detecting an area for acquiring correction information based on the received input image and the read image read;
An area determination step for determining the detected area based on the area and a peripheral area of the area;
A program for causing a computer of the image processing system to execute a correction information update step of updating the stored correction information based on an image portion included in an input image and a read image in the determined area.

Images