JP2012169775A - Image processing device, image forming apparatus, and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing device that checks the quality of printed materials accurately in a short time.SOLUTION: An image processing device includes: a block density calculation unit 25 that, during printing, calculates the average density of respective blocks obtained by dividing a page image based on image data for printing, and, after printing, calculates the average density of respective blocks obtained by dividing a page image based on image data created by reading a printed material printed based on the image data for printing; and a quality determination unit 26 that compares the average density of the blocks calculated from the image data for printing during printing and the average density of the blocks calculated from the image data created by image reading after printing, and determines the quality of the printed material based on the comparison result.

Description

  The present invention relates to an image processing apparatus, an image forming apparatus, and an image processing method.

  In recent years, the printing speed of image forming apparatuses such as electrophotographic printers and multi-function printers has been remarkably improved, and it is possible to print a large number of pages in a short time. For example, in a multi-function peripheral, it is possible to print an original of several hundred pages in less than 10 minutes. Since it takes a considerable amount of time to visually check the quality of such a printed matter, means for improving the quality of the printed matter after printing is desired.

  A certain inkjet printer reads an image printed on printing paper with a sensor and compares the image data used for printing with the image data generated by the sensor to check the quality of the printed image. (For example, refer to Patent Document 1).

JP-A-5-14637

  However, in the above-described printing apparatus, since image data is compared for each pixel, the amount of calculation for the quality confirmation process increases, and the time required for the quality confirmation process increases.

  In addition, when image data is compared for each pixel, even if skew feeding, uneven conveyance speed, or slight misalignment of printing paper occurs in the paper conveyance, the pixel position is misaligned, so the quality can be confirmed accurately. There is no possibility.

  Furthermore, in an electrophotographic image forming apparatus, dot variations due to dot gain fluctuations and toner scattering are relatively large in a printed image. When image data is compared for each pixel, quality confirmation can be performed accurately. There is no possibility.

  SUMMARY An advantage of some aspects of the invention is that it provides an image processing apparatus, an image forming apparatus, and an image processing method capable of accurately checking the quality of printed matter in a short time.

  In order to solve the above problems, the present invention is configured as follows.

  An image processing apparatus according to the present invention includes a first block feature value calculation unit that calculates a reference feature value for each of blocks obtained by dividing a page image based on print image data, and a printed matter printed based on the print image data. A second block feature value computing unit that computes a printed product feature value for each of the blocks obtained by dividing the page image based on the image data generated by reading the image data, and a reference feature value computed by the first block feature value computing unit And a printed matter feature value computed by the second block feature value computing unit, and a quality determining unit for judging the quality of the printed matter based on the comparison result.

  Thereby, since the quality check is performed by comparing the feature values of the blocks, the quality of the printed matter can be checked accurately in a short time.

  In addition to the image processing apparatus described above, the image processing apparatus according to the present invention may be configured as follows. In this case, the image processing apparatus further includes a storage unit. For each page to be printed, the first block feature value calculation unit stores the reference feature value for the block for the page in the storage unit, and the quality determination unit stores the reference feature value stored in the storage unit for each page. And the printed product feature value are compared, and the quality of the printed material is determined for each page of the printed material based on the comparison result.

  As a result, the quality of the printed matter can be checked for each page.

  The image processing apparatus according to the present invention may be as follows in addition to any of the image processing apparatuses described above. In this case, the reference feature value and the print product feature value are average densities of the blocks.

  Thereby, it becomes easy to calculate the feature value of the block in a short time.

  The image processing apparatus according to the present invention may be as follows in addition to any of the image processing apparatuses described above. In this case, the block is a rectangular pixel region having a predetermined first pixel number in the main scanning direction and a predetermined second pixel number in the sub-scanning direction.

  Thereby, it becomes easy to calculate the feature value of the block in a short time.

  The image processing apparatus according to the present invention may be as follows in addition to any of the image processing apparatuses described above. In this case, the image processing apparatus is generated by reading the printed matter printed based on the first character type histogram calculation unit that calculates the character type histogram of the characters in the page image based on the print image data and the print image data. And a second character type histogram calculation unit that calculates a character type histogram of characters in the page image based on the image data. The quality determination unit compares the reference feature value and the printed matter feature value, compares the character type histogram calculated by the first character type histogram calculation unit and the character type histogram calculated by the second character type histogram calculation unit, The quality of the printed matter is determined based on the comparison result.

  Thereby, the quality check of printed matter can be performed more accurately.

  The image processing apparatus according to the present invention may be as follows in addition to any of the image processing apparatuses described above. In this case, the printed material is printed by an electrophotographic method.

  An image forming apparatus according to the present invention includes any of the image processing apparatuses described above.

  Thereby, the quality check of printed matter can be performed accurately in a short time.

  An image processing method according to the present invention includes a step of calculating, as a reference feature value, a feature value for each block obtained by dividing a page image based on print image data, and reading a printed matter printed based on the print image data. The feature value for each of the blocks obtained by dividing the page image based on the image data generated by the step is calculated as the print product feature value, and the reference feature value and the print product feature value are compared, and the quality of the print product based on the comparison result Determining.

  Thereby, since the quality check is performed by comparing the feature values of the blocks, the quality of the printed matter can be checked accurately in a short time.

  According to the present invention, it is possible to accurately check the quality of printed matter in a short time.

FIG. 1 is a perspective view showing an image forming apparatus which is an example of an image processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus according to the first embodiment. FIG. 3 is a flowchart illustrating print processing of the image forming apparatus according to the first embodiment. FIG. 4 is a flowchart for describing image reading and quality confirmation processing for a printed matter of the image forming apparatus according to the first embodiment. FIG. 5 is a block diagram illustrating a configuration of the image forming apparatus according to the second embodiment. FIG. 6 is a diagram for explaining a character type histogram in the second embodiment. FIG. 7 is a flowchart illustrating print processing of the image forming apparatus according to the second embodiment. FIG. 8 is a flowchart for explaining image reading and quality confirmation processing for a printed matter of the image forming apparatus according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.

  FIG. 1 is a perspective view showing an image forming apparatus which is an example of an image processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus 1 according to the first embodiment.

  An image forming apparatus 1 shown in FIG. 1 has an electrophotographic printer function and a scanner function, and performs image processing with the configuration shown in FIG.

  As illustrated in FIG. 2, the image forming apparatus 1 includes a printing device 11, an image reading device 12, an operation panel 13, a storage device 14, a communication device 15, and a controller 16.

  The printing apparatus 11 is an internal apparatus that prints an image page by page on a printing sheet in an electrophotographic manner based on printing image data. The image data for printing includes raster image data generated by scanning by the image reading device 12, raster image data generated from PDL (Page Description Language) data, and a raster image generated by facsimile reception by a built-in facsimile device (not shown). Data.

  Further, the image reading device 12 feeds a document such as a printed matter with an auto document feeder (ADF) 12a, for example, optically reads the image of the document page by page, and generates image data of each page image. It is an internal device.

  The operation panel 13 is disposed on the surface of the casing of the image forming apparatus 1 and includes a display device that displays various information to the user and an input device that detects a user operation. For example, a liquid crystal display is used as the display device. A key switch, a touch panel, or the like is used as the input device.

  The storage device 14 is a device capable of storing various data and programs. For example, image data generated by a copy job, a print job, a scan job, or the like is stored in the storage device 14 as necessary. As the storage device 14, a nonvolatile large-capacity storage medium such as a nonvolatile memory or a hard disk drive is used.

  The communication device 15 is a circuit that is connected to a computer network (not shown) and performs data communication with other devices (such as a host device) connected to the network.

  The controller 16 has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and loads a program from the ROM or the storage device 14 to the RAM. By executing it, various processing units are realized. In this embodiment, in the controller 16, a print processing unit 21, a scan processing unit 22, a UI processing unit 23, a job management unit 24, a block density calculation unit 25, and a quality determination unit 26 are realized.

  The print processing unit 21 generates print data based on the print image data, supplies the print data to the printing apparatus 11, and executes printing. The print image data is raster image data. The print data is data obtained from image data for printing by image processing such as halftoning.

  The scan processing unit 22 controls the image reading device 12, automatically feeds a document (printed material) with the ADF 12a, reads an image of the document (printed material) page by page, and generates raster image data of each page image. .

  The UI processing unit 23 controls the operation panel 13 to display various types of information on the operation panel 13 and accepts user operations on the operation panel 13.

  The job management unit 24 receives a job request received from a host device (not shown) via the communication device 15 and a job request based on a user operation on the operation panel 13, and uses the print processing unit 21, the scan processing unit 22, and the like. And execute the accepted job.

  The block density calculation unit 25 reads a first block feature value calculation unit that calculates a reference feature value for each of the blocks obtained by dividing the page image based on the print image data, and a printed matter printed based on the print image data. It functions as a second block feature value computing unit that computes a printed product feature value for each of the blocks obtained by dividing the page image based on the image data generated in this way.

  In the first embodiment, the reference feature value and the print feature value are average densities of blocks. In the first embodiment, each block is a rectangular pixel region having a predetermined first pixel number in the main scanning direction and a predetermined second pixel number in the sub-scanning direction.

  The quality determination unit 26 compares the above-described reference feature value for the corresponding block with the above-described printed material feature value, and determines the quality of the printed material based on the comparison result.

  In the first embodiment, the block density calculation unit 25 stores, for each printed page, the reference feature value for the block for the page in a RAM (not shown) or the storage device 14 in the controller 16 when printing the printed matter. When the printed material is scanned, for each page of the printed material, the printed material characteristic value for the block for the page is stored in a RAM (not shown) in the controller 16, and the quality determination unit 26 receives from the RAM or the like. The reference feature value and the print product feature value of each block in the page stored for each page are read and compared, and the quality of the print product is determined for each page of the print product based on the comparison result.

  Next, the operation of the image forming apparatus according to the first embodiment will be described.

  Here, an operation at the time of printing and an operation at the time of image reading and quality confirmation will be described.

(1) Operation during printing

  FIG. 3 is a flowchart illustrating print processing of the image forming apparatus according to the first embodiment.

  When receiving a print job based on a user operation on the operation panel 13 or a print request from a host device (not shown) (Step S1), the job management unit 24 causes the print processing unit 21 to execute printing. At this time, for example, when receiving the PDL data, the job management unit 24 performs rasterization from the PDL data and generates image data for printing.

  At this time, for example, when the print mode is selected from the normal mode and the quality confirmation mode by the user and the quality confirmation mode is selected, the reference block density data is calculated in step S4 described later, and the normal mode is selected. When is selected, calculation of reference block density data in step S4 described later is not performed.

  The print processing unit 21 generates print data by performing image processing such as halftoning on the printing image data page by page (step S2), and supplies the generated print data to the printing apparatus 11 to The page is printed (step S3). Further, the block density calculation unit 25 calculates, as reference block density data, the average density for each of a plurality of blocks obtained by dividing the page image from the print image data for the page (step S4).

  When the print image data is monochrome, the average density of the block is the average of the pixel values of a plurality of pixels constituting the block. When the image data for printing is color, for example, the average density of the block is an average of pixel values of a plurality of pixels constituting the block after gray-scale conversion. Alternatively, when the image data for printing is color, for example, the average density of the block is the block for each color coordinate (R, G, B in RGB color space, C, M, Y in CMY color space, etc.). The average of the color coordinate values of a plurality of constituent pixels is used.

  The block density calculation unit 25 stores reference block density data for the page in a RAM (not shown). The block density data for one page has a page number and the same density value as the number of blocks obtained by dividing the page.

  In this way, printing is performed page by page, and reference block density data is generated and stored for each page.

  Then, the job management unit 24 causes printing for each page and generation of block density data in order up to the last page, and when the printing for the last page and generation of block density data are finished, this print job is finished. (Step S5).

(2) Operation during image reading and quality confirmation

  FIG. 4 is a flowchart for describing image reading and quality confirmation processing for a printed matter of the image forming apparatus according to the first embodiment.

  When the quality confirmation mode is selected as described above, reference block density data is calculated in step S4 described later, and when the print job is completed, the job management unit 24 immediately waits for a scan job to be accepted. For example, when a user sets a printed matter generated by a print job in the ADF 12a and performs a scan execution operation on the operation panel 13, the operation is detected by the UI processing unit 23, and the scan job is detected by the job management unit. 24 (step S11).

  When the job management unit 24 receives a scan job, the job management unit 24 causes the scan processing unit 22 to read each page image of the document (here, the above-described printed material). The scan processing unit 22 feeds a document page by page (one page) by the ADF 12a, reads a page image of the fed document, counts up the page number every time the page image of one page is read, and Raster image data is generated (step S12).

  When reading the page image of one page, the scan processing unit 22 determines whether or not the page is a blank page (step S13). Blank page determination is performed by an existing method.

  When the page is not a blank page, the block density calculation unit 25 calculates an average density for each of a plurality of blocks obtained by dividing the page image from the image data of the page generated by the scan processing unit 22. Calculation is made as printed block density data (step S14). At this time, the method of dividing the page image into a plurality of blocks (the shape and size of each block and the number of blocks) is the same as the method of dividing at the time of printing. Therefore, the printed product block density data of this page has the same number of density values as the density values in the reference block density data of this page.

  As described above, when the printed block density data of this page is obtained, the quality determination unit 26 refers to the page number in the reference block density data, identifies the reference block density data for this page, and The average density value of each block in the reference block density data is compared with the average density value of the corresponding block in the printed block density data for this page, and the absolute value of the difference between the two is the predetermined threshold value for the total number of blocks. It is determined whether or not the ratio of the number of blocks below is equal to or greater than a predetermined threshold (step S15).

  When the absolute value of the difference between the average density values is equal to or less than a predetermined threshold for the page, the quality determination unit 26 determines that the reference block density data and the printed block density data are equal to or greater than the predetermined threshold. It is determined that they match. If the reference block density data matches the printed product block density data, the print quality of this page is good, and the scan processing unit 12 immediately causes the next page to be scanned.

  On the other hand, for this page, when the ratio of the number of blocks in which the absolute value of the difference between the average density values is less than or equal to a predetermined threshold is less than the predetermined threshold, the quality determination unit 26 determines that the reference block density data and the print block density data And the UI processing unit 23 is used to display an error message indicating that the print quality of the current page is poor on the operation panel 13 (step S16), the process is interrupted, and the user Wait for the operation to continue. When the UI processing unit 23 detects an operation to continue processing on the operation panel 13, the scan processing unit 12 causes the next page to be scanned.

  If it is determined in step S13 that this page is a blank page, the quality determination unit 26 reads the reference block density data of this page, and the average density value of all the blocks on this page is less than a predetermined threshold value. (That is, whether or not this page of the document is a blank page) (step S17). If this page of the document is a blank page, the print quality of this page is good, and the scan processing unit 12 scans the next page.

  On the other hand, when this page of the document is not a blank page, the print quality of this page is poor. Therefore, the quality determination unit 26 uses the UI processing unit 23 to check that the print quality of the current page is bad. An error message is displayed on the operation panel 13 (step S18), the process is interrupted, and the operation for continuing the process by the user is awaited. When the UI processing unit 23 detects an operation to continue processing on the operation panel 13, the scan processing unit 12 causes the next page to be scanned. In this case, this page of the scanned printed material is a blank page, but this page of the document is not a blank page. Therefore, a blank page is mixed due to double feeding of printing paper at the time of printing, or the printed material is fed incorrectly in the ADF 12a. Judging, the scan processing unit 22 does not count up the page number for the scan.

  In this way, scanning and quality confirmation are executed page by page.

  Then, the job management unit 24 sequentially scans each page and confirms the print quality until the last page. When the scan and the print quality confirmation for the last page are finished, the scan job is finished (step S1). S19).

  As described above, according to the first embodiment, the block density calculation unit 25 calculates the average density for each of the blocks obtained by dividing the page image based on the print image data during printing, and after printing, An average density is calculated for each of the blocks obtained by dividing the page image based on the image data generated by reading the printed matter printed based on the printing image data. The quality determination unit 26 compares the average density of the blocks calculated from the printing image data during printing with the average density of the blocks calculated from the image data generated by image reading after printing, and the comparison result To determine the quality of the printed material.

  As a result, since the quality check is performed by comparing the average density of the blocks, the size of the data to be held after printing can be reduced until the quality check is completed, and skewing, conveyance speed unevenness, dot gain fluctuations, and toner scattering are reduced. The print quality can be accurately confirmed in a short time without being affected by variations in dots in the printed image due to the above.

Embodiment 2. FIG.

  In Embodiment 2 of the present invention, a character type histogram obtained from image data for printing and a character type histogram obtained from image data generated by image reading after printing are compared, and the quality of the printed matter is determined based on the comparison result. To do.

  FIG. 5 is a block diagram illustrating a configuration of the image forming apparatus according to the second embodiment.

  As shown in FIG. 5, in the second embodiment, a character type histogram calculation unit 41 and a quality determination unit 42 are realized in the controller 16.

  The character type histogram calculation unit 41 calculates, for each page, the character type histogram of characters in the page image based on the print image data, and converts the print data printed based on the print image data into image data generated by reading the printed matter. Based on the page, a character type histogram of characters in the page image is calculated for each page.

  Here, the character type histogram will be described. FIG. 6 is a diagram for explaining a character type histogram in the second embodiment.

  The character type histogram is obtained by counting the appearance frequency of a specific character type in one page for each character type. The character type histogram in the second embodiment indicates the appearance frequency for each of the 50 hiragana characters as shown in FIG. 6A, for example. The appearance frequency may be the number of appearances or the ratio of the number of appearances of the character type to the total number of characters in one page. Or, for example, as shown in FIG. 6B, the character type histogram is 1 depending on the appearance frequency of some specific character types (here, a, i, u, e, o) and other character types. You may make it include the appearance frequency about a group.

  The character type histogram may calculate the application frequency one character at a time for a predetermined character type having a high appearance frequency, and may include the appearance frequency of the group by setting a plurality of predetermined character types having a low appearance frequency as one group.

  The character type histogram calculation unit 41 uses, for example, OCR (Optical Character Recognition) technology to perform character recognition on the image data for printing and the image data generated by scanning the printed matter, thereby converting the characters of each character type into those characters. And the appearance frequency of each character type is calculated.

  The quality determination unit 42 is generated by comparing the reference feature value and the print product feature value in the same manner as the quality determination unit 26 of the first embodiment, and reading the character type histogram calculated from the print image data and the print product. The character type histogram calculated from the image data is compared, and the quality of the printed matter is determined based on the comparison result.

  The other components in FIG. 5 are the same as those in the first embodiment, and a description thereof will be omitted.

  Next, the operation of the image forming apparatus according to the second embodiment will be described.

  Here, an operation at the time of printing and an operation at the time of image reading and quality confirmation will be described.

(1) Operation during printing

  FIG. 7 is a flowchart illustrating print processing of the image forming apparatus according to the second embodiment.

  In the second embodiment, when printing each page, the block density calculation unit 25 calculates the reference block density data from the print image data (step S4), and the character type histogram calculation unit 41 calculates the character type from the print image data. A histogram (hereinafter, this character type histogram is referred to as a reference histogram) is generated, and the reference histogram is stored in a RAM (not shown) (step S31).

  Since other operations during printing are the same as those in the first embodiment, description thereof is omitted.

(2) Operation during image reading and quality confirmation

  FIG. 8 is a flowchart for explaining image reading and quality confirmation processing for a printed matter of the image forming apparatus according to the second embodiment.

  In the second embodiment, at the time of scanning each page, the block density calculation unit 25 generates print product block density data from the image data generated by reading the print (step S14), and the character type histogram calculation unit 41 performs the print product. A character type histogram (hereinafter, this character type histogram is referred to as a printed material histogram) is generated from the image data generated by reading (step S41). Note that the character type (or group of character types) whose appearance frequency is calculated in the printed matter histogram is the same as the character type (or group of character types) whose appearance frequency is calculated in the above-described reference histogram.

  In the second embodiment, the quality determination unit 42 compares the block densities (step S15), calculates the absolute value of the difference in appearance frequency of each character type in the reference histogram and the printed material histogram, and calculates the total number of character types. Then, it is determined whether or not the proportion of character types whose absolute value of the difference in appearance frequency of each character type is equal to or smaller than a predetermined threshold is equal to or greater than a predetermined threshold (step S42).

  Then, the quality determination unit 42 determines that the reference histogram matches the printed material histogram when the ratio of the character types whose absolute value of the difference in appearance frequency is equal to or smaller than a predetermined threshold is equal to or larger than the predetermined threshold. If the reference histogram matches the printed matter histogram, the print quality of this page is good, and the scan processing unit 12 immediately causes the next page to be scanned.

  On the other hand, for this page, when the ratio of character types whose absolute value of the difference in appearance frequency is equal to or smaller than a predetermined threshold is less than the predetermined threshold, the quality determination unit 42 determines that the reference histogram and the printed matter histogram do not match. Then, using the UI processing unit 23, an error message indicating that the print quality of the current page is poor is displayed on the operation panel 13 (step S16), the process is interrupted, and the operation for continuing the process by the user is awaited. When the UI processing unit 23 detects an operation to continue processing on the operation panel 13, the scan processing unit 12 causes the next page to be scanned.

  Since other operations during image reading and quality confirmation are the same as those in the first embodiment, description thereof is omitted.

  As described above, according to the second embodiment, the character type histogram calculation unit 41 calculates the character type histogram of characters in the page image based on the print image data, and prints the printed matter based on the print image data. A character type histogram of characters in the page image based on the image data generated by reading is calculated. And the quality determination part 42 compares the above-mentioned reference | standard feature value and printed matter characteristic value, compares these character type histograms, and determines the quality of printed matter based on those comparison results.

  Thereby, the quality check of printed matter can be performed more accurately. By comparing the character type histograms, it is difficult to be affected by noise generated during printing or image reading, and the quality can be accurately confirmed.

  Each embodiment described above is a preferred example of the present invention, but the present invention is not limited to these, and various modifications and changes can be made without departing from the scope of the present invention. It is.

  For example, in each of the embodiments described above, the threshold for the density difference for the block may be changed according to the average density of the block for the print image data.

  In the above embodiment, the present invention is applied to the image forming apparatus 1 including the printing apparatus 11 and the image reading apparatus 12. However, independent printers and scanners are connected via a communication medium such as a computer network. In the connected system, the above-described processing may be performed in a terminal such as a printer or a scanner, or a host device connected to the communication medium.

  The present invention can be applied to, for example, quality confirmation of a printed matter generated by an image forming apparatus.

25 block density calculator (an example of a first block feature value calculator, an example of a second block feature value calculator)
26, 42 Quality determination unit 41 Histogram calculation unit (an example of a first character type histogram calculation unit, an example of a second character type histogram calculation unit)

Claims (8)

A first block feature value calculation unit for calculating a reference feature value for each of the blocks obtained by dividing the page image based on the print image data;
A second block feature value computing unit for computing a printed product feature value for each of the blocks obtained by dividing the page image based on the image data generated by reading the printed material printed based on the printing image data;
A quality determination for comparing the reference feature value calculated by the first block feature value calculation unit with the print feature value calculated by the second block feature value calculation unit and determining the quality of the print based on the comparison result And
An image processing apparatus comprising: A storage means,
The first block feature value calculation unit stores, for each page to be printed, the reference feature value for the block for the page in the storage unit,
The quality determining unit compares the reference feature value stored for each page in the storage unit with the printed matter feature value, and determines the quality of the printed matter for each page of the printed matter based on the comparison result. ,
The image processing apparatus according to claim 1.   The image processing apparatus according to claim 1, wherein the reference feature value and the printed matter feature value are average densities of the blocks.   4. The block is a rectangular pixel region having a predetermined first number of pixels in the main scanning direction and a predetermined second number of pixels in the sub-scanning direction. The image processing apparatus according to claim 1. A first character type histogram calculation unit for calculating a character type histogram of characters in the page image based on the print image data;
A second character type histogram calculation unit that calculates a character type histogram of characters in a page image based on image data generated by reading a printed matter printed based on the print image data;
The quality determination unit compares the reference feature value with the printed product feature value, and compares the character type histogram calculated by the first character type histogram calculation unit and the character type histogram calculated by the second character type histogram calculation unit. Comparing, and determining the quality of the printed matter based on the comparison results;
The image processing apparatus according to claim 1, wherein:   The image processing apparatus according to claim 1, wherein the printed matter is printed by an electrophotographic method.   An image forming apparatus comprising the image processing apparatus according to claim 1. Calculating a feature value for each of the blocks obtained by dividing the page image based on the print image data as a reference feature value;
Calculating a feature value for each of the blocks obtained by dividing the page image based on the image data generated by reading the printed matter printed based on the printing image data, as a printed matter feature value;
Comparing the reference feature value and the printed matter feature value, and determining the quality of the printed matter based on the comparison result;
An image processing method comprising:

Images