Inspection device, image processing method, and program

Abstract

To enable easy setting of appropriate inspection criteria for a printed matter.SOLUTION: A control unit of an inspection PC waits until a print image is received, analyzes the layout of the print image when receiving the print image, detects objects constituting the print image, and calculates inspection areas. The control unit causes the inspection areas and inspection levels of the detected objects to be displayed in an inspection level numeric box on a UI in the inspection PC. The inspection level for each object displayed in the inspection level numeric box is set as the average value of the inspection levels used in the past ten inspections for each object. The control unit acquires the contents of the inspection level numeric box and the type of object corresponding to each numeric value, and updates the inspection levels in an inspection level table stored in an HDD.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an image processing technology for inspecting the quality of printed matter.

Background Art

[0002] There is known an inspection apparatus that reads a printed matter printed by a printing apparatus with a scanner and detects defects such as dirt and printing omission on the printed matter from a read image. In order to perform the inspection, it is necessary to set an inspection area in an area to be inspected on the read image and to set a defect detection standard for the inspection area. Patent Document 1 discloses a technique for setting an inspection area and an inspection standard according to an object based on user input in order to appropriately perform such an inspection. When areas to which inspection standards are applied overlap within an image, it is presented so that the user can easily grasp whether the inspection is performed with a desired inspection standard.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, since the user manually inputs the setting of the inspection standard according to the object, there is a problem that the labor and time required for user input increase as the number of objects for which the inspection standard is individually set increases.

[0005] Therefore, an object of the present invention is to enable easy setting of an appropriate inspection standard for printed matter.

Means for Solving the Problems

[0006] The present invention relates to an inspection apparatus, which comprises: setting means for setting an inspection level that defines a defect detection criterion for a printed matter according to characteristic information of the printed matter, for an inspection apparatus that inspects the printed matter; and storage means for storing the inspection level used in the inspection in the inspection apparatus in association with the characteristic information, wherein the setting means updates the inspection level to be set in the inspection apparatus based on the inspection level stored in the storage means.

Effect of the Invention

[0007] According to the present invention, an appropriate inspection criterion for a printed matter can be easily set.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present invention according to the claims, and not all combinations of the features described in this embodiment are essential for the solution means of the present invention.

[0010] (Embodiment 1) Hereinafter, the image forming apparatus according to this embodiment will be described with reference to the drawings.

[0011] FIG. 1 is a diagram showing an overall configuration example of an image forming apparatus 1000 in Embodiment 1 to which the present embodiment is applied. As shown in FIG. 1, the image forming apparatus 1000 includes an image forming apparatus main body 1100, an image reading apparatus 1300, and a paper discharge unit 1400. A client PC 1200, which is an example of a terminal device, is connected to the image forming apparatus main body 1100 via a communication line 1201 such as a network. The client PC 1200 transmits print data to the image forming apparatus main body 1100. The image forming apparatus main body 1100 receives the print data transmitted by the client PC 1200 via the communication line 1201 and performs printing based on the received print data. A reading unit 1110 is provided on the upper part of the image forming apparatus main body 1100. The reading unit 1110 includes an ADF 1110A and a document reading unit 1110B. The ADF 1110A includes a document tray 1111, a paper feed path 1112, a paper discharge tray 1113, a contact type image sensor 1114, a density reference member 1115, and the like. The density reference member 1115 is used during shading correction of the ADF 1110A. The document reading unit 1110B includes a document illumination unit 1116, a reflection mirror 1117, a condenser lens 1118, a sensor 1119, a platen glass 1120, and the like. The reading unit 1110 separates and feeds out the documents set on the document tray 1111 one by one, conveys them in the sub-scanning direction along the paper feed path 1112 where the contact type image sensor 1114 is disposed, and discharges them to the paper discharge tray 1113. The document illumination unit 1116 includes a lamp 1116A and a mirror 1116B. While the document is being conveyed in the sub-scanning direction along the paper feed path 1112, the reading operation for each line in the main scanning direction is repeatedly executed by the document illumination unit 1116, the reflection mirror 1117, the condenser lens 1118, and the sensor 1119.

[0012] The image forming apparatus main body 1100 includes a control unit 1160, an image forming unit 1130, a fixing unit 1140, a paper feeding unit 1150, and the like. The control unit 1160 performs image processing on the original image data acquired from the client PC 1200 to generate a print image, and transmits it to the image forming unit 1130. Details will be described later. The control unit 1160 also controls the image forming unit 1130, the fixing unit 1140, the paper feeding unit 1150, and the like. The image forming unit 1130 includes an exposure device 1131, a developing device 1132, a photosensitive drum 1133, and a transfer belt 1134. The image forming unit 1130 supplies different color toners to the photosensitive drum 1133 by the exposure device 1131 and develops the image based on the print image data received from the control unit 1160 or the image data of the original read by the reading unit 1110. The image forming unit 1130 transfers the toner image developed on the photosensitive drum 1133 to the paper supplied from the paper feeding unit 1150 by the transfer belt 1134. The image forming unit 1130 melts the toner of the toner image transferred to the paper by the fixing unit 1140, thereby fixing the color image on the paper. The image reading device 1300 is arranged in an in-line manner on the downstream side of the image forming apparatus main body 1100, and reads the image printed on one or both sides of the paper on which the image is formed. In the following description, it is assumed that the image reading device 1300 is arranged in an in-line manner. However, the image reading device 1300 may be arranged in an off-line manner on the downstream side of the image forming apparatus main body 1100.

[0013] The image reading device 1300 includes a control unit 1360, an image reading unit 1340A, an image reading unit 1340B, a colorimeter 1350, background members 1330A to 1330C, a conveyance unit 1320, and a conveyance path 1310. The control unit 1360 transmits the read image acquired from the image reading unit 1340 to the control unit 1160. Details will be described later. Also, the control unit 1360 controls the conveyance unit 1320, the background members 1330, the image reading unit 1340, the colorimeter 1350, etc. The conveyance path 1310 is a path through which the paper passes. The conveyance unit 1320 conveys the paper on which an image is formed. Therefore, the paper is conveyed along the conveyance path 1310 by the drive of the conveyance unit 1320. When the image reading device 1300 receives, for example, a paper supplied from the image forming apparatus main body 1100, it causes the image reading units 1340A and 1340B and the colorimeter 1350 to read the image formed on the paper. The reading result of the image (hereinafter referred to as a read image) may be output to the image forming apparatus main body 1100 or the like. Specifically, each of the image reading unit 1340A and the image reading unit 1340B is disposed at a position facing either one of the front and back sides of the paper passing through the conveyance path 1310. The image reading unit 1340A is disposed at a position for reading the back surface of the paper. The reading result of the image reading unit 1340A may be used, for example, for checking the deviation between the front and back surfaces of the image printed on the paper or for checking the presence or absence of an unexpected image. On the other hand, the image reading unit 1340B is disposed at a position for reading the front surface of the paper. Specifically, the image reading unit 1340B reads the image printed on the paper. As the paper is conveyed, the image reading unit 1340B reads the color of the image formed on the paper along the orthogonal direction orthogonal to the advancing direction of the paper, that is, the main scanning direction. When the image reading unit 1340A and the image reading unit 1340B are collectively referred to, they are referred to as the image reading unit 1340. The image reading unit 1340 is composed of, for example, a scanner of a CCD sensor method or a CIS method. When the background members 1330A to 1330C are collectively referred to, they are referred to as the background member 1330.

[0014] The paper discharge unit 1400 has paper discharge destinations 1410 and 1420, conveyance paths 1430, 1440, 1450, and a reversing unit 1460. The paper that has passed through the image reading unit passes through the conveyance path 1430 and is conveyed from the conveyance path 1440 when the paper discharge destination 1410 is used, and is conveyed from the conveyance path 1450 when the paper discharge destination 1420 is used. The reversing unit 1460 reverses the paper once so that the direction of the incoming paper is the same as the direction of the paper at the time of paper discharge. The paper discharge destination of the printed matter may be selectively used, for example, the paper discharge destination 1410 when the inspection result is normal (OK), and the paper discharge destination 1420 when the inspection result is abnormal (NG).

[0015] Next, with reference to FIG. 2, the control for inspecting the finish of the printed matter will be described.

[0016] The control unit 1160 of the image forming apparatus main body 1100 includes a control unit 2001 such as a CPU and a memory 2002 such as a ROM and a RAM. Further, 1100 includes an HDD 2003, LAN interfaces 2004 and 2005 as communication interfaces, and a video interface 2006 for outputting image data to the image forming apparatus. The control unit 2001 reads a program from the memory 2002 according to the processing content and executes the program to control the operation of the image forming apparatus main body 1100. Various data stored in the HDD 2003 are referred to when the control unit 2001 controls the operation of the image forming apparatus main body 1100. Note that the HDD 2003 is not limited to an HDD, and may be other storage devices such as an SSD or a memory card.

[0017] The LAN interface 2004 is a communication interface for receiving print data and the like from the client PC 1200. The print data includes, as a data structure, for example, a PJL (Print Job Language) part and a subsequent PDL (Page Description Language) part. The PJL part is a print command language for controlling the image forming apparatus main body 1100. The PDL part is a page description language. The LAN interface 2005 is a communication interface for receiving an image from the image reading apparatus 1300.

[0018] The control unit 2001 performs screen processing, that is, raster image processing for dot screening, so that the print data generated by the client PC 1200 can be printed by the image forming apparatus main body 1100. The raster image processing, that is, RIP, generates a raster image. The raster image is data of a rasterized image and is image data constituting a so-called RIP image. The generated raster image is stored in the HDD 2003. When printing is executed, the control unit 3001 reads out the raster image stored in the HDD 2003 and further performs image correction. When image processing is performed, the control unit 2001 performs image processing, generates a print image, and stores it in the HDD 2003. Further, the control unit 2001 transmits the print image as a video signal to the image forming unit 1130, and the image forming unit 1130 forms an image on the paper. Note that the HDD 2103 is not limited to an HDD, and may be another storage device such as an SSD or a memory card.

[0019] The image formed on the paper is read by the image reading device 1300. The control unit 1360 of the image reading device 1300 includes a control unit 2101 such as a CPU and a memory 2102 such as a ROM and a RAM. The 1360 further includes an HDD 2103, a LAN interface 2104 as a communication interface, and an I / O interface 2105 that acquires the read image data acquired by the image reading unit 1340. The control unit 2101 reads out a program from the memory 2102 according to the processing content and executes the program to control the operation of the image reading device 1300. Various data stored in the HDD 2103 are referred to when an example of control means such as the control unit 2101 controls the operation of the image reading device 1300.

[0020] The read image is transmitted to the control unit 1160 via the LAN interface 2104 through the control unit 2101. The control unit 2001 of the control unit 1160 that has received the read image compares the raster image with the read image and inspects the finish of the printed matter by determining whether there is an abnormality in the printed matter. Details will be described later.

[0021] The inspection PC2000 represents the control configuration for inspecting the finish of the printed matter in this embodiment. The inspection PC2000 includes a control unit 2201 such as a CPU and a memory 2202 such as a ROM and a RAM. Also, the inspection PC2000 includes an HDD2203 and a LAN interface 2204 as a communication interface. The control unit 2201 reads a program from the memory according to the processing content and executes the program to control the operation of the inspection PC2000. Various data stored in the HDD2203 are referred to when the control unit controls the operation of the inspection PC2000. Also, the GPU2205 is a processor that performs the computational processing necessary for image processing and executes instructions regarding image processing from the control unit 2201. Note that the HDD2203 is not limited to an HDD and may be other storage devices such as an SSD or a memory card.

[0022] FIG. 3 shows a flowchart for explaining the processing on the image forming apparatus main body 1100 side among the processes for inspecting the finish of the printed matter in Embodiment 1. In this embodiment, a case where print data including the image shown in FIG. 5 is input and printed and the printed matter is inspected will be exemplified and described. Note that S3001 to S3007 in the flowchart are realized by the control unit 2001 such as a CPU reading and executing a program stored in the memory 2002. S3101 to S3104 in the flowchart are realized by the control unit 2101 such as a CPU reading a program stored in the memory 2102. S4001 to S4015 in the flowchart are realized by the control unit 2201 such as the CPU of the inspection PC calling a program stored in the memory 2202.

[0023] The control unit 2001 of the image forming apparatus main body 1100 starts processing when, for example, the power is turned on.

[0024] In S3001, the control unit 2001 waits until it receives a print image, and when it receives print data from the client PC1200, it proceeds to S3002.

[0025] In S3002, the control unit 2001 performs raster image processing on the received print data. For example, print data such as PDL is rasterized through a display list to generate a raster image, which is then stored in the HDD 2003.

[0026] In S3003, the control unit 2001 generates a print image based on the print setting information from the raster image generated in S3002. Here, the print setting information includes information related to the finish of the printed matter, such as magnification, color adjustment, and page number addition.

[0027] In S3004, the control unit 2001 sends the print image generated in S3003 to the inspection PC 2000.

[0028] In S3005, the control unit 2001 forms an image on the paper based on the print image and ends the process.

[0029] FIG. 4 shows a flowchart for explaining the processing on the inspection PC 2000 side among the processes for inspecting the finish of the printed matter in Embodiment 1.

[0030] In S4001, the control unit 2201 of the inspection PC waits until it receives the print image and then receives the print image.

[0031] In S4002, the control unit 2201 analyzes the layout of the print image, detects the objects that make up the print image, and calculates the inspection area. Here, the information about the objects that make up the detected print image is used as the feature information of the printed matter.

[0032] FIG. 5 shows a diagram for explaining the detection of objects, which are elements constituting the image for printing, and the inspection area. First, layout analysis of the image for printing is performed to detect an image area, character area objects, and background image objects from the image for printing. The background area object refers to an area obtained by excluding the image area and character area objects from the entire image for printing. Further, for the layout analysis of the image for printing, a machine learning model that has been learned to analyze the layout stored in the HDD 2203 in advance is used. Examples of the machine learning model used for layout analysis include PubLayNet (2021, Zejiang Shen et al.) for a machine learning model learned to analyze the layout. The method for analyzing the layout is not limited to the machine learning model, and characters and images may be detected by analyzing the histogram of luminance values. In the present embodiment, the image area 5002, character area objects 4003, and background area objects 4004 are detected from the image for printing 5001 by layout analysis.

[0033] Furthermore, the image area 4002 is analyzed to detect various objects within the image area 4002. For object detection within the image area 4002, a machine learning model that has been learned to detect objects in the image stored in the HDD 2203 in advance is used. Examples of the machine learning model used for object detection include Detectron2 (Facebook AI Research). In the example shown in FIG. 4, a face object 4005, a passenger car object 4006, and a truck object 4007 are detected from the image area by object analysis.

[0034] FIG. 6 shows a diagram for explaining the inspection area of the detected object. The inspection area is composed of graphic information surrounding the object and coordinate information representing the position of the object. FIG. 6 shows a state where the inspection area of each object is set. In the present embodiment, the graphic information includes information indicating the shape and size such as a rectangle or an ellipse like the inspection areas 6001 to 6004 shown in FIG. 5, and the size is selected so that the area when surrounding the object is minimized. The coordinate information is information indicating the coordinates for determining the position of the inspection area of the object. When the graphic information is a rectangle, the top left and bottom right vertex coordinates are used. When the graphic information is an ellipse, the top left and bottom right vertex coordinates of a rectangle circumscribing the ellipse are used. For example, for the rectangular inspection area 6002, the top left vertex coordinates (M, N) 6005 and the bottom right vertex coordinates (M + A, M + B) 6006 are held as coordinate information. Although two vertex coordinates are exemplified as the coordinate information, information that uniquely determines a rectangle and an ellipse, such as the lengths of two sides orthogonal to one vertex coordinate, or the center coordinate and the distance from the center, may also be used.

[0035] Here, the non-inspection area 6007 where no object is detected within the image area 5002 may be treated as an image area object or as the background object 5004. In the present embodiment, it will be described as being treated as the background object 5004. Regarding the overlapping area between the inspection area and the non-inspection area, the inspection area where an object is detected shall be preferentially treated. For example, the area where the inspection area 6003 and the non-inspection area 6007 overlap shall be treated as the inspection area 6003 where the track object 5007 is detected. Also, the inspection level that defines the detection criteria for defects in the printed matter set for each inspection area is set according to the objects included in each inspection area based on the inspection level set in advance for each object. When multiple objects are detected in the same inspection area, the inspection level of that inspection area shall be set to the highest inspection level among the inspection levels set for each detected object. The inspection level set for an inspection area shall be applied to all objects within the inspection area. Regarding the overlapping area between inspection areas, the highest inspection level among the inspection levels of the multiple overlapping inspection areas shall be set.

[0036] In S4003, the control unit 2201 causes the inspection PC 2000 to display an inspection condition setting screen indicating the inspection area and inspection level of the detected object on a UI (not shown) provided in the inspection PC 2000.

[0037] Figure 7 shows an example of an inspection condition setting screen to be displayed on the UI of the inspection PC2000 in this embodiment. This inspection condition setting screen is composed of a preview area 7000 for an object and an inspection area, an inspection level numeric box 7001, an inspection condition setting completion button 7002, and an inspection level update check box 7003. The user can check the inspection level for each object from the value displayed in the inspection level numeric box 7001 and change the inspection level as needed. In this embodiment, the inspection level has six levels from 0 to 5. Inspection level 5 represents performing the most stringent inspection, and as the numeric value of the inspection level decreases, the inspection criteria are relaxed. That is, the size and density difference of dirt and defect such as scratches determined to be abnormal are the smallest at inspection level 5 and the largest at inspection level 1. Inspection level 0 means "exclusion" from the inspection target of the object, and no inspection is performed on the object with inspection level 0 set. Thus, at each inspection level, different values are set for the thresholds for each parameter such as the size and density difference of the defect that serves as the detection criteria for defects determined to be abnormal.

[0038] The inspection condition setting completion button 7002 is a button for the user to confirm the inspection settings. When the user has completed changing the inspection level, the user can confirm the inspection settings by pressing the inspection condition setting completion button 7002. The inspection level update check box 7003 is a check box for setting whether to update the inspection level in an inspection level table described later.

[0039] FIG. 8 shows an inspection level table used to determine the recommended value to be displayed in the inspection level numeric box 7001 in the present embodiment. In the inspection level table 8000 shown in FIG. 8, the object type 8001 and the inspection level 8002 for each object used in past inspections are held. In the present embodiment, the inspection levels for 10 times including the latest setting and the past settings are held, but it is not limited to 10 times, and it may be one time or more, and may be 100 times or 1000 times. Also, the user may be able to specify how many times to hold the inspection level. Note that the initial value of the inspection level table 8000 may be set by the user via a UI (not shown), or a predetermined value may be set. Alternatively, the incidental information corresponding to the size, shape, and position on the printing image of the recognized object may also be held in the inspection level table 8000. That is, although only the inspection level is held for each past setting in the inspection level table 8000, the incidental information indicating the size, shape, and position on the printing image of the object may be further held in addition to the inspection level for each past setting. Thereby, even for the same object, the value to be displayed in the inspection level numeric box 7001 can be calculated based only on the inspection level used for the object having the same kind of incidental information. Similarly, the object types may be classified by distinguishing each position on the printing image, and different inspection levels may be set. Also, as the object type, for example, even the same object such as "face (large)", "face (medium)", "face (small)", etc. may be classified as different object types for each size, shape, and position on the printing image, and different inspection levels may be set for each. Thus, the inspection level table 8000 is not limited to the form shown in FIG. 8, and various changes are possible.

[0040] In this embodiment, the inspection level for each object to be displayed in the inspection level numeric box 7001 is the average value of the inspection levels for 10 times, which combines the latest setting and the past settings for each object. For example, since the average value of the inspection levels for the past 10 times regarding the face object 5005 is 2.2, the decimal part is truncated and it becomes 2. Similarly, the inspection level of the passenger car object 5006 is 2, the inspection level of the truck object 5007 is 3, the inspection level of the character object is 1, and the inspection level of the background object is 0. Note that the value displayed in the inspection level numeric box 7001 is not limited to the average value of the inspection levels used in a predetermined number of inspections, and may be the inspection level that was most frequently used in past inspections. The value displayed in this inspection level numeric box 7001 may be a value calculated by collecting the inspection level data of a plurality of inspection apparatuses and using all the inspection level data used in those plurality of inspection apparatuses. Further, when the inspection level table 8000 holds additional information, among the inspection levels of the object types corresponding to the detected objects, only the inspection levels with similar size, shape, and position within the image based on the additional information may be used for calculation. Also, a predetermined coefficient may be determined for each parameter included in the additional information, and the inspection level corresponding to the additional information may be calculated by multiplying the inspection level set for each object type by the coefficient corresponding to the additional information. For example, if the coefficient for the object size being "large" is 1, "medium" is 0.5, and "small" is 0, and the inspection level of the face object is 3, then depending on the size, the inspection level is 3 when "large", 2 when "medium", and 0 when "small". The calculation method of the inspection level to be displayed in the inspection level numeric box 7001 is not limited to these forms, and various changes are possible.

[0041] In S4004, the control unit 2201 waits until it detects the pressing of the inspection condition setting completion button 7002, and when it detects the pressing of the inspection condition setting completion button 7002, it proceeds to S4005.

[0042] In S4005, the control unit 2201 determines whether or not the inspection level update checkbox 7003 is checked. If the inspection level update checkbox 7003 is checked, the process proceeds to S4006. If the inspection level update checkbox 7003 is not checked, the process proceeds to S4007.

[0043] In S4006, the control unit 2201 acquires the content of the inspection level numeric box 7001 and the type of the object corresponding to each numeric value, and updates the inspection level 8002 of the inspection level table 8000 stored in the HDD 2203. In the present embodiment, the values of the inspection level numeric boxes 7001 for the face object, passenger car object, truck object, character object, and background object are stored in the latest settings 8003 to 8008, respectively. Also, the previous latest setting is overwritten by the setting 8009 of the past 1, the setting 8009 of the past 1 is overwritten by the setting 8010 of the past 2, and similarly, all are updated up to the setting 8011 of the past 9. As a result, when inspecting the next print, the value of the inspection level numeric box 7001 displayed is calculated based on the values from the updated latest setting to the setting 8011 of the past 9, so that the setting change by the user can be reduced.

[0044] If it is determined in S4005 not to update the inspection level, the inspection level table 8000 is not updated. This is to prevent a special value from affecting the subsequent inspection level by saving the value in the inspection level table 8000 when the inspection level setting is special. As a result, even when an inspection is performed with a special inspection level set, at the subsequent inspection, a standard inspection level suitable for many cases can be displayed in the inspection level numeric box 7001 without being affected by the special inspection level.

[0045] In S4007, the control unit 2201 waits until it receives a read image from the control unit 2101 of the image reading device 1300, and when it receives the read image, the process proceeds to S4008.

[0046] Here, the processing of the control unit 2101 of the image reading device 1300 will be described.

[0047] In S3101, the control unit 2101 waits until a read image is acquired, and when a read image is acquired, it proceeds to S3102.

[0048] In S3102, the control unit 2101 transmits the acquired read image to the control unit 1160 and ends the process.

[0049] Now, return to the description of the processing of the control unit 2201 of the inspection PC 2000. The control unit 2201 performs inspections from S4008 to S4011 based on the inspection condition settings set in S4003.

[0050] In S4008, the control unit 2201 starts inspecting each pixel of the read image received from the control unit 2101 based on the inspection condition settings stored in the HDD 2203. For this purpose, in S4008, S4008 to S4011 are repeatedly executed until the inspection of all pixels of the read image is completed while sequentially changing the target pixel.

[0051] In S4009, the control unit 2201 determines whether the inspection level of the target pixel is 0. If it is not 0, it proceeds to S4010 to perform the inspection, and if it is 0, it proceeds to S4011 without performing the inspection. Note that the object is composed of a plurality of pixels, and the inspection level of the target pixel is the inspection level of the object detected in the inspection area containing the target pixel.

[0052] In S4010, the control unit 2201 inspects the target pixel. For the inspection to be performed, for example, the density value of the target pixel in the read image may be compared with the density value of the pixel in the printing image at the position corresponding to the target pixel. Regarding the inspection result, it is determined whether it exceeds the threshold value according to the inspection level. If it exceeds, it is determined as abnormal, and if it does not exceed, it is determined as normal and saved in the HDD 2203. The corresponding position may be a pixel having the same coordinates as the target pixel, or when the position is corrected, the corrected position may be the same coordinates. When the inspection is performed by comparing pixels in this way, the threshold value may be an allowable value for the density difference between the target pixels. Also, in the inspection, instead of the density value, the color difference between the corresponding pixels of the printing image and the read image may be compared with the reference value. The color difference may be represented, for example, as the distance in the color space. The distance in the specific color space according to the inspection level becomes the threshold value for determining whether it is normal. The stricter the inspection level, the smaller the distance in the color space that becomes the threshold value. Regarding the inspection result, it is determined whether it is equal to or greater than the threshold value according to the inspection level. If it is equal to or greater than the threshold value, it is determined as abnormal, and if it is less than the threshold value, the inspection result determined as normal is saved in the HDD 2203.

[0053] In S4011, if the inspection has not been completed for all pixels, the control unit 2201 returns to S4008 and performs the inspection until the inspection is completed for all pixels. When the inspection is completed for all pixels, it proceeds to S4012.

[0054] In S4012, the control unit 2201 refers to the inspection result saved in the HDD 2203 in S4011. If it is YES, it proceeds to S4013. If it is NO, it proceeds to S4014 and ends, assuming that the necessary inspection has been completed.

[0055] In S4013, the control unit 2201 issues an NG notification indicating an abnormality. Note that the NG notification only needs to notify the user, a maintenance worker, or the like that an abnormality exists. For example, it may be displayed on a display panel (not shown) of the image forming apparatus main body 1100. Since the notification form of the NG notification is not particularly limited, it may be a notification by voice of a human voice, or a notification in a pattern of blinking or lighting of one or a plurality of lamps of a patrol lamp. Further, when separating the paper discharge destination between the printed matter determined to be normal (OK) and the printed matter determined to be abnormal (NG), a configuration may be adopted in which the NG notification is made by discharging the printed matter to the paper discharge destination determined to be abnormal (NG).

[0056] As described above, by automatically displaying and setting the inspection level according to the object based on the inspection level used in the past inspection of the inspection level according to the object, it is possible to reduce the labor of the user manually changing the inspection level.

[0057] In addition, in the present embodiment, the update processes (S4005, S4006) for updating the inspection level are performed before the inspection processes (S4008 to S4013) for inspection, but the order of the update process and the inspection process may be reversed.

[0058] (Embodiment 2) In Embodiment 1, when calculating the inspection level based on the feature information of the printed matter, the inspection level was calculated in units of objects. In contrast, in the present embodiment, a genre for classifying the types of objects is added as the feature information of the printed matter, and the inspection level is calculated in consideration of the genre of the object. In the description of the present embodiment, the same constituent elements and the same processing steps as those in Embodiment 1 are basically given the same numbers and the description thereof is omitted. Hereinafter, the description will be centered on the parts different from Embodiment 1. Unless otherwise specified, the parts not particularly mentioned are basically the same as those in the foregoing Embodiment 1.

[0059] Fig. 9 shows an inspection condition setting screen to be displayed on the UI of the inspection PC 2000 in this embodiment. The inspection condition setting screen in this embodiment includes an object genre 9000, an object genre selection checkbox 9001, and an object selection checkbox 9002. The object genre 9000 includes multiple types of objects. For example, in the vehicle object genre, it includes objects such as passenger cars, trucks, and buses. Similarly, the animal object genre includes objects such as dogs, cats, and birds. Here, the relationship between the object genre and the object may be predetermined or may be appropriately changeable from a UI (not shown). The relationship between the object genre and the object is not limited to these forms.

[0060] The object genre selection checkbox 9001 and the object selection checkbox 9002 are checkboxes for selecting whether to calculate the inspection level based on the object genre or based on the object. For example, when the object selection checkbox 9002 is selected, the inspection level "2" is calculated based on the past inspection level of a passenger car, and the inspection level "3" is calculated based on the past inspection level of a truck. Although a passenger car and a truck are of the same genre, when the object selection checkbox 9002 is selected, the inspection levels are calculated separately for the passenger car and the truck. On the other hand, as shown in Fig. 9, when the object genre selection checkbox 9001 is selected, since a passenger car and a truck are of the same genre, a common inspection level (here, inspection level "2") is calculated for their inspection levels.

[0061] Figure 10 shows an inspection level table 10000 used to determine the recommended value to be displayed in the inspection level numeric box in this embodiment. The inspection level is saved by associating the object genre 10001 with the object type 8001. When the object genre selection checkbox 9001 is selected in this embodiment, the value of the inspection level numeric box 7001 is the average value of the past 10 times for all objects existing in the object genre. For example, since the average value of all objects existing in the vehicle object genre is "2", the inspection level numeric boxes 7001 for passenger cars and trucks are both calculated and displayed as "2". The inspection level for each genre may be selected from among a plurality of inspection levels calculated for each object for a plurality of objects of the same genre, or one inspection level may be calculated for each genre without distinguishing between a plurality of objects of the same genre.

[0062] As described above, in this embodiment, when there are many objects with the same object genre in the image for printing, the user can automatically set the inspection level based on the inspection level used in the past inspection for each object genre with a simple operation.

[0063] (Embodiment 3) Regarding Embodiments 1 and 2, the inspection level was calculated using the information about the objects in the image for printing as the feature information of the printed matter. In contrast, in this embodiment, it is possible to calculate the inspection level according to the type of the printed matter for printed matters such as forms where the objects recognized from the image are not emphasized. In principle, the same numbers are added to the same constituent elements and the same processing steps, and the description is omitted. Hereinafter, the different parts will be mainly described. Unless otherwise specified, in principle, it is the same as in the aforementioned Embodiments 1 and 2.

[0064] Fig. 11 shows an inspection condition setting screen to be displayed on the UI of the inspection PC 2000 in the present embodiment. The inspection condition setting screen in the present embodiment includes a preview area 7000, a printed matter checkbox 11000, a printed matter type checkbox 11001 for selecting the type of printed matter, and an inspection level numeric box 11002 corresponding to the printed matter. The printed matter checkbox 11000 is for switching whether to set the inspection level according to the printed matter. In the present embodiment, the printed matter checkbox 11000, the object genre selection checkbox 9001, and the object selection checkbox 9002 are in an exclusive relationship. When the printed matter checkbox is checked, a diagonal line 11003 is displayed in the display area for setting the inspection conditions for each object genre and object. In the present embodiment, examples of the types of printed matter include forms, postcards, and envelopes, but the types of printed matter are not limited to these. The printed matter type checkbox 11001 is a checkbox for selecting the printed matter. In the present embodiment, the case where a form is checked is exemplified.

[0065] Fig. 12 is an inspection level table 12000 used to determine the recommended value to be displayed in the inspection level numeric box in the present embodiment. Forms, postcards, and envelopes, which are the types of printed matter, are each treated as an object, and the inspection level is saved. The value of the inspection level numeric box 11002 in the present embodiment is calculated from the average value of the past 10 times in the same manner as in Embodiment 1 by treating the printed matter in the same way as an object. For example, since the average value of the form object is 2.9, it is displayed as 3. In the present embodiment, when the printed matter checkbox 11000 is selected, the same inspection level is applied to all objects included in the print image.

[0066] Although the printed matter check box 11000 is in an exclusive relationship with the object genre selection check box 9001 and the object selection check box 9002, it may be possible to make them coexist. For example, the inspection level of the printed matter object may be applied only to the background object, and the inspection level for each object or object genre may be applied to each object included in the printed image. The settings regarding the printed matter and the object or object genre are not limited to this embodiment and can be variously changed. Also, the type of printed matter may be specified based on user input, or the control unit 2201 may specify it from the printed image using a machine learning model or the like.

[0067] As described above, in this embodiment, by treating the type of printed matter itself as an object and calculating the inspection level for each printed matter, the user can automatically set the inspection level based on the inspection level used in past inspections for each type of printed matter with a simple operation.

[0068] The present invention is not limited to the above-described Embodiments 1 to 3, and various modifications (including organic combinations of each embodiment) are possible based on the gist of the present invention, and they are not excluded from the scope of the present invention. That is, all configurations combining the above-described embodiments and their modified forms are also included in the present invention.

[0069] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

[0070] This disclosure includes the following configurations and methods. [Configuration 1] Setting means for setting an inspection level that defines a defect detection criterion for the printed matter according to the characteristic information of the printed matter with respect to an inspection apparatus that inspects the printed matter; Storage means for storing the inspection level used in the inspection in the inspection apparatus in association with the characteristic information; Comprising: The setting means updates the inspection level to be set in the inspection apparatus based on the inspection level stored in the storage means. An inspection apparatus characterized by this. [Configuration 2] The setting means: Acquisition means for acquiring a printing image used for printing the printed matter; First detection means for detecting an object from the printing image acquired by the acquisition means; Including: The setting means uses information about the object detected by the first detection means as the characteristic information. The inspection apparatus according to Configuration 1, characterized by this. [Configuration 3] The setting means sets the inspection level for each object based on the characteristic information. The inspection apparatus according to Configuration 2, characterized by this. [Configuration 4] The setting means sets an inspection area corresponding to the object, and sets the inspection level set for the object corresponding to the inspection area for the pixels included in the inspection area. The inspection apparatus according to Configuration 3, characterized by this. [Configuration 5] For the pixels included in the overlapping area where a plurality of the inspection areas overlap, the inspection level is the highest inspection level among the inspection levels set for the objects corresponding to the plurality of overlapping inspection areas. The inspection apparatus according to Configuration 4, characterized by this. [Configuration 6] The setting means includes a specifying means for specifying the type of the printed matter based on the information about the object detected by the first detection means, and uses the specified type of the printed matter as the feature information. The inspection apparatus according to any one of Claims 2 to 5, wherein the inspection apparatus is characterized by this. [Configuration 7] The feature information of the printed matter further includes a second detection means for detecting the type of the object from the printing image. The setting means sets the inspection level for each genre that classifies the type of the object detected by the second detection means. The inspection apparatus according to any one of Claims 2 to 6, wherein the inspection apparatus is characterized by this. [Configuration 8] In addition to the inspection level, the storage means stores additional information related to at least one of the size, shape, and position on the printing image of the object. When updating the set inspection level, the setting means updates it to the inspection level calculated based on the inspection level and the additional information stored in the storage means. The inspection apparatus according to any one of Claims 2 to 7, wherein the inspection apparatus is characterized by this. [Configuration 9] The setting means includes a receiving means for receiving, from a user, information indicating the type of the printed matter as the feature information. The inspection apparatus according to any one of Claims 1 to 8, wherein the inspection apparatus is characterized by this. [Configuration 10] A step of setting an inspection level for defining a defect detection criterion of the printed matter according to the feature information of the printed matter for an inspection apparatus for inspecting the printed matter, A step of storing, in a storage device, the inspection level used in the inspection in the inspection apparatus, and The setting step updates the inspection level set for the inspection apparatus based on the inspection level stored in the storage device. An image processing method characterized by this. [Configuration 11] A program for causing a computer to function as the inspection apparatus according to any one of Configurations 1 to 9.

Claims

1. Setting means for setting an inspection level that defines a defect detection criterion for the printed matter according to the characteristic information of the printed matter with respect to an inspection apparatus for inspecting the printed matter; Storage means for storing the inspection level used in the inspection in the inspection apparatus in association with the characteristic information; Comprising: The setting means updates the inspection level to be set in the inspection apparatus based on the inspection level stored in the storage means. An inspection apparatus characterized by this.

2. The setting means: Acquisition means for acquiring a printing image used for printing the printed matter; First detection means for detecting an object from the printing image acquired by the acquisition means; Including: The setting means uses information about the object detected by the first detection means as the characteristic information. The inspection apparatus according to claim 1, characterized by this.

3. The setting means sets the inspection level for each object based on the characteristic information. The inspection apparatus according to claim 2, characterized by this.

4. The setting means sets an inspection area corresponding to the object, and sets the inspection level set for the object corresponding to the inspection area for the pixels included in the inspection area. The inspection apparatus according to claim 3, characterized by this.

5. For the pixels included in the overlapping area where a plurality of the inspection areas overlap, the inspection level is the highest inspection level among the inspection levels set for the objects corresponding to the plurality of overlapping inspection areas. The inspection apparatus according to claim 4, characterized by this.

6. The setting means includes specifying means for specifying the type of the printed matter based on information about the object detected by the first detection means, and uses the specified type of the printed matter as the characteristic information. The inspection apparatus according to claim 2, characterized by this.

7. The characteristic information of the printed matter further includes second detection means for detecting the type of the object from the printing image. The setting means sets the inspection level for each genre for classifying the type of the object detected by the second detection means. The inspection apparatus according to claim 2, characterized by this.

8. In addition to the inspection level, the storage means stores additional information related to at least one of the size, shape, and position on the printing image of the object. When updating the set inspection level, the setting means updates it to the inspection level calculated based on the inspection level stored in the storage means and the attached information. The inspection apparatus according to claim 2, characterized in that.

9. The setting means includes a receiving means for receiving, from a user, information indicating the type of the printed matter as the characteristic information. The inspection apparatus according to any one of claims 1 to 8, characterized in that.

10. For an inspection apparatus that inspects a printed matter, a step of setting an inspection level that defines a defect detection criterion for the printed matter according to the characteristic information of the printed matter, A step of storing the inspection level used for the inspection in the inspection apparatus in a storage device, Comprising, In the setting step, the inspection level set for the inspection apparatus is updated based on the inspection level stored in the storage device. An image processing method, characterized in that.

11. A program for causing a computer to function as the inspection apparatus according to any one of claims 1 to 8.

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