Inspection system and image forming system

Abstract

To reduce a burden on a user in image inspection.SOLUTION: Reading means reads an image formed on a sheet to be conveyed. Detection means detects an area of a content in a reference image that is an image to be a reference in inspection of the image on the sheet. Display means displays a setting screen for setting an inspection level (indicating the reference of inspection of the image) corresponding to the detected area of the content. Inspection means inspects the image on the sheet corresponding to the area of the content at the inspection level set on the setting screen, based on first image data obtained by the reading means reading the image on the sheet and second image data corresponding to the reference image. The display means displays a screen for selecting whether to validate setting the inspection level corresponding to the area of the content detected by the detection means.SELECTED DRAWING: Figure 8C

Description

[Technical field]

[0001] The present invention relates to inspection systems and imaging systems. [Background technology]

[0002] Conventionally, a printing system has been proposed in which an inspection device inspects an image on a sheet printed by a printing device (Patent Document 1). The inspection device reads the image printed on the sheet and judges pass / fail by comparing the image with a correct image.

[0003] Patent Document 1 proposes that an area of ​​an image printed on a sheet that is to be inspected by an inspection device is set as an inspection area, and the inspection device performs inspection in the inspection area. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-14085 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the user must register a correct image and set the inspection area using the correct image. In commercial printing, etc., a large number of correct images are required. That is, in the configuration described in Patent Document 1, the user must manually set the inspection area for each of the many correct images, which lacks usability. On the other hand, when the inspection level is automatically set for multiple inspection areas, the user must check whether the inspection area for which the inspection level is automatically set is the inspection area as intended by the user. If the inspection level is automatically set for many inspection areas, the user's confirmation work will increase, and usability may be lacking. Therefore, the present invention aims to reduce the burden on the user in image inspection. [Means for solving the problem]

[0006] The present invention relates to, for example, A reading means for reading an image formed on a sheet being conveyed; a detection means for detecting an area of ​​a content in a reference image which is an image serving as a reference for inspection of the image on the sheet; a display means for displaying a setting screen for setting an inspection level corresponding to the area of ​​the content detected by the detection means and indicating a standard for inspecting the image; an inspection means for inspecting the image on the sheet corresponding to the region of the content at the inspection level set on the setting screen, based on first image data obtained by the reading means reading the image on the sheet and second image data corresponding to the reference image; The display means displays a screen for selecting whether or not to enable setting of the inspection level corresponding to an area of ​​the content detected by the detection means, and provides an inspection system. Effect of the Invention

[0007] According to the present invention, the burden on a user in image inspection is reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram for explaining an image processing system. [Diagram 2] A diagram explaining the electrical hardware. [Diagram 3] A diagram illustrating the mechanical hardware. [Figure 4] 6 is a flowchart showing a process of an external controller and a flowchart showing a process of an image forming apparatus. [Diagram 5] FIG. 13 is a diagram illustrating a UI for registering correct image data. [Figure 6] FIG. 13 is a diagram illustrating a UI for registering correct image data. [Figure 7]FIG. 13 is a diagram illustrating a UI for registering correct image data. [Figure 8A] A diagram explaining the UI for environment settings. [Figure 8B] A diagram explaining the UI for environment settings. [Figure 8C] A diagram explaining the UI for environment settings. [Figure 9] 11 is a flowchart showing a method for registering correct image data. [Figure 10] FIG. [Figure 11] FIG. 13 is a diagram illustrating a UI for selecting a candidate correct image. [Figure 12] 11 is a flowchart showing adding / deleting a correct image. [Figure 13] A diagram illustrating a UI for adding / deleting correct images. [Figure 14] FIG. 13 is a diagram illustrating a UI for adding a correct image. [Figure 15] FIG. 13 is a diagram illustrating a UI for setting an inspection job. [Figure 16] 1 is a flowchart illustrating an image inspection method. [Figure 17] A diagram explaining the UI for displaying inspection results. [Figure 18] A diagram explaining the UI for displaying inspection results. [Figure 19] FIG. 2 is a diagram for explaining functions realized by a CPU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the following description, the external controller may be called an image processing controller, a digital front end (hereinafter, DFE), a print server, etc. The image forming device may be called a printer, a multifunction device, or a multifunction peripheral (MFP). An example of an image processing device will be described below.

[0010] (1) Overview of the image processing system FIG. 1 is a diagram for explaining an image processing system 100. The image processing system 100 includes an image forming system 101, an external controller 102, and a PC 103. PC is an abbreviation for personal computer. The PC 103 may be a smartphone or a tablet terminal. The image forming system 101 and the external controller 102 are communicatively connected via an internal LAN 105 and a video cable 106. LAN is an abbreviation for local area network. The external controller 102 is communicatively connected to the PC 103 via an external LAN 104. The PC 103 transmits a print instruction to the external controller 102.

[0011] A printer driver is installed in the PC 103. The printer driver converts print data into a print description language (e.g., page description language) that can be processed by the external controller 102. A user issues a print instruction from various applications via the printer driver. The printer driver transmits print data to the external controller 102 based on the print instruction from the user.

[0012] The external controller 102 receives a print instruction and print data from the PC 103. The external controller 102 analyzes the print data, performs rasterization processing, and transmits the print data to the image forming system 101.

[0013] The image forming system 101 is connected to a plurality of devices having different functions, and executes complicated processes such as bookbinding. The image forming device 107 forms an image on a sheet conveyed from a feed unit at the bottom of the image forming device 107 using toner. The inserter 108 inserts an insertion sheet at an arbitrary position into a group of sheets printed by the image forming device 107 and conveyed. The inspection device 109 reads an image printed on a sheet conveyed from the image forming device 107, and compares it with preregistered correct image data to determine whether the image printed on the sheet is acceptable. If the image is unacceptable, the inspection device 109 changes the sheet discharge operation. The large-capacity stacker 110 can stack and accommodate a large number of sheets. The finisher 111 performs a finishing process on the conveyed sheets. The finishing process includes, for example, stapling, punching, or saddle-stitching. The finished product is discharged to a discharge tray.

[0014] Although an external controller 102 is connected to the image forming system 101, this is merely an example. The image forming system 101 may be connected to an external LAN 104, and print data may be transmitted from a PC 103 to the image forming system 101. In this case, the image forming system 101 performs analysis of the print data, rasterization processing, and the like.

[0015] (2) Electrical hardware 2 is a block diagram showing the electrical hardware of the image forming system 101, the external controller 102, and the PC 103. Note that the functions described below may be realized by at least one processor.

[0016] Image forming equipment The image forming apparatus 107 has a communication I / F 217, a LAN I / F 218, a video I / F 220, a HDD (hard disk drive) 221, a CPU 222, a memory 223, an operation unit 224, and a display 225. I / F is an abbreviation for interface. CPU is an abbreviation for central processing unit. The image forming apparatus 107 further has a document exposure unit 226, a laser exposure unit 227, an image creating unit 228, a fixing unit 229, and a feeding unit 230. These components are connected via a system bus 231.

[0017] The communication I / F 217 is a communication circuit connected to the inserter 108, the inspection device 109, the large-capacity stacker 110, and the finisher 111 via a communication cable 254. The LAN I / F 218 is a communication circuit connected to the external controller 102 via the internal LAN 105. The LAN I / F 218 receives, for example, print data from the external controller 102. The video I / F 220 is a communication circuit connected to the external controller 102 via a video cable 106. The video I / F 220 receives image data from the external controller 102.

[0018] The HDD 221 stores programs and data. The CPU 222 loads the programs stored in the HDD 221 into the memory 223 and executes the loaded programs to perform image processing control, print control, and the like. The memory 223 includes a random access memory (RAM) and a read-only memory (ROM). The memory 223 stores programs and image data required when the CPU 222 performs various processes. The operation unit 224 is an input device that accepts input of various settings and operation instructions from the user. The display 225 presents and displays setting information of the image forming system 101, the processing status of a print job, and the like to the user. The display 225 may have a touch panel function as part of the operation unit 224.

[0019] The document exposure unit 226 is an image reading device that reads a document and generates image data when using the copy function and the scan function. The document exposure unit 226 uses an exposure lamp to illuminate a document placed on the platen glass by a user or a document fed from a document feed unit (not shown), and generates image data by reading the document with an image sensor. The laser exposure unit 227 uniformly charges the surface of the photosensitive drum and irradiates the photosensitive drum with laser light to form an electrostatic latent image. The image creation unit 228 is a device that transfers toner to a sheet, and includes a developing unit, a transfer unit, a toner supply unit, and the like. The developing unit forms a toner image by attaching toner from a developing cylinder to the electrostatic latent image on the surface of the photosensitive drum. The transfer unit applies a positive potential to the primary transfer roller and transfers toner from the photosensitive drum surface to the intermediate transfer belt (primary transfer). The transfer unit applies a positive potential to the secondary transfer outer roller and transfers toner from the intermediate transfer belt to the sheet (secondary transfer). The fixing unit 229 includes a heater, a fixing belt, a pressure belt, etc., and fixes the toner image transferred to the sheet to the sheet by heat and pressure. The feeding unit 230 is a device for feeding the sheet to be used for printing to the image creating unit 228, and the sheet feeding operation and transport operation are controlled by rollers and various sensors.

[0020] Inserter The inserter 108 has a communication I / F 232, a CPU 233, and a memory 234, and each of these components is connected via a system bus 236. The communication I / F 232 is a communication circuit that is connected to the image forming apparatus 107 via a communication cable 254 and executes communication required for control. The CPU 233 executes a control program stored in the memory 234 to perform various controls required for feeding sheets. The memory 234 is a storage device that stores the control program. The CPU 233 controls the rollers and sensors in accordance with the control program, while controlling the feeding section of the inserter 108 and controlling the feeding and transport of sheets conveyed from the image forming apparatus 107.

[0021] Inspection equipment The inspection device 109 has a communication I / F 237, a CPU 238, a memory 239, a CIS 331 and a CIS 332, a display 241, and an operation unit 242. These are connected via a system bus 243. CIS is an abbreviation of contact image sensor. The communication I / F 237 is a communication circuit that is connected to the image forming device 107 via a communication cable 254 and executes communication required for control. The CPU 238 performs various controls required for inspection according to a control program stored in the memory 239. The memory 239 is a storage device that stores the control program. The CIS 331 and the CIS 332 read the conveyed sheet based on an instruction from the CPU 238. The CIS 331 and the CIS 332 not only read the printed matter to be inspected, but also read the printed matter that is a candidate for the correct image in order to register the correct image data. That is, image data is acquired from a plurality of printed matters that are candidates for the correct image. The CPU 238 applies image processing (e.g., resolution conversion, noise removal, superimposition, averaging) to the image data, generates correct image data, and stores it in the memory 239. Note that the correct image data may be, for example, RIP image data transmitted from the PC 103.

[0022] The CPU 238 compares the image data of the inspection target acquired by the CIS 331 and the CIS 332 with the correct image data stored in the memory 239, and judges whether the printed image (sheet) passes or fails. The CPU 238 instructs the transport control of the sheet that is judged to be a failure. The display 241 displays the inspection results, a setting screen, and the like. The operation unit 242 is operated by the user, and accepts instructions such as changing the settings of the inspection device 109 and registering correct image data.

[0023] ●Large capacity stacker The large-capacity stacker 110 has a communication I / F 244, a CPU 245, and a memory 246. These are connected via a system bus 248. The communication I / F 244 is a communication circuit that is connected to the image forming apparatus 107 via a communication cable 254 and executes communication required for control. The CPU 245 executes a control program stored in the memory 246 to perform various controls required for discharge. The memory 246 is a storage device that stores the control program. The CPU 245 conveys the conveyed sheet to a stack tray 341, an escape tray 346, or a subsequent finisher 111 in accordance with the control program.

[0024] Finisher The finisher 111 has a communication I / F 249, a CPU 250, a memory 251, and a post-processing unit 253. These are connected via a system bus 255. The communication I / F 249 is a communication circuit that is connected to the image forming apparatus 107 via a communication cable 254 and executes communication required for control. The CPU 250 executes a control program stored in the memory 251 to perform various controls required for finishing and discharge. The memory 251 is a storage device that stores the control program and the like. The CPU 250 controls the transport and discharge of sheets according to the control program. The post-processing unit 253 executes finishing processes such as stapling, punching, and saddle stitching based on instructions from the CPU 250.

[0025] External Controller The external controller 102 includes a CPU 208, a memory 209, a HDD 210, a keyboard 211, a display 212, a LAN I / F 213, a LAN I / F 214, and a video I / F 215. These are connected via a system bus 216. The CPU 208 loads a program stored in the HDD 210 into the memory 209 and executes the loaded program. The CPU 208 receives print data from the PC 103, executes RIP processing, and transmits print data to the image forming system 101. The memory 209 stores programs and data required for the CPU 208 to perform various processes. The HDD 210 stores programs and data required for operations such as print processing. The keyboard 211 accepts an operation instruction from the external controller 102 and inputs the operation instruction to the CPU 208. The display 212 displays information, still images, and moving images of applications executed by the external controller 102. The LAN I / F 213 is a communication circuit that is connected to the PC 103 via the external LAN 104 and executes communication such as print instructions. The LAN I / F 214 is a communication circuit that is connected to the image forming system 101 via the internal LAN 105 and executes communication such as print instructions. The video I / F 215 is a communication circuit that is connected to the image forming system 101 via the video cable 106 and executes communication such as print data.

[0026] ●PC (information processing device) The PC 103 includes a CPU 201, a memory 202, a HDD 203, a keyboard 204, a display 205, and a LAN I / F 206. These are connected via a system bus 207. The CPU 201 loads a document processing program and the like stored in the HDD 203 into the memory 202, and executes the loaded program to create print data and execute a print instruction. The CPU 201 executes a print instruction to add a pattern designated by a user to the background of the print data. This pattern may include a pattern indicating the device-specific number of the image forming device 107. The CPU 201 may shift the position of the pattern for each page and add it to the background. The CPU 201 comprehensively controls each device connected to the system bus 207. The memory 202 stores programs and data required for the CPU 201 to perform various processes. The HDD 203 stores programs and data required for operations such as print processing. The keyboard 204 is an input device that accepts operations and instructions for the PC 103. A display 205 displays information, still images, and moving images of applications executed by the PC 103. A LAN I / F 206 is connected to the external LAN 104, and is a communication circuit that executes communication such as printing instructions.

[0027] In FIG. 2, the external controller 102 and the image forming system 101 are connected via an internal LAN 105 and a video cable 106, but this is merely an example. It is sufficient that data necessary for printing can be transmitted and received. For example, the external controller 102 and the image forming system 101 may be connected only by a video cable. Each of the memory 202, the memory 209, the memory 223, the memory 234, the memory 239, the memory 246, and the memory 251 may be a storage device capable of holding data and programs. For example, these may be replaced by a volatile RAM, a non-volatile ROM, an internal HDD, an external HDD, a USB memory, or the like.

[0028] (3) Mechanical Hardware FIG. 3 is a structural cross-sectional view showing in a simplified manner the mechanical hardware of the image forming system 101. As shown in FIG.

[0029] Image forming equipment The image forming apparatus 107 prints an image on a sheet fed from the feeding devices 301 and 302 constituting the feeding section 230. The feeding devices 301 and 302 may be called a feeding deck, a sheet cassette, or a sheet tray. The feeding devices 301 and 302 separate the topmost sheet from a plurality of sheets and convey it to a conveying path 303. The developing stations 304 to 307 form a toner image using color toners of yellow "Y", magenta "M", cyan "C", and black "K", respectively, to form a color image. The developing stations 304 to 307 each have a laser exposure section 227 and an image forming section 228. The laser exposure section 227 outputs a light beam such as a laser beam modulated according to image data. The laser beam is reflected by a rotating polygon mirror such as a polygon mirror and irradiated onto a photosensitive drum. As a result, an electrostatic latent image is formed on the photosensitive drum. The electrostatic latent image is developed by toner to become a toner image. This series of image forming processes is performed for each of the YMCK toners. The intermediate transfer belt 308 transports each of the YMCK toner images to a secondary transfer unit 309. The secondary transfer unit 309 transfers the toner images onto a sheet transported via a transport path 303. The display 225 displays the printing status of the image forming system 101 and information required for settings.

[0030] The fixing section 229 includes fixing units 311 and 313. The fixing unit 311 fixes the toner image transferred to the sheet to the sheet. The fixing unit 311 includes a pressure roller and a heating roller. When the sheet passes between the pressure roller and the heating roller, the toner melts, and the melted toner is pressed onto the sheet. This fixes the toner image onto the sheet. The sheet that has passed through the fixing unit 311 is conveyed to a conveying path 315 through a conveying path 312. Depending on the type of sheet, further melting and pressing may be required. In this case, the sheet that has passed through the fixing unit 311 is conveyed to the fixing unit 313 through a conveying path 318. The sheet to which the additional melting and pressing have been applied is conveyed to the conveying path 315 through a conveying path 314. When the image forming mode is double-sided, the sheet is conveyed to a reversing path 316, where the traveling direction of the sheet is reversed. This changes the image forming side from the first side of the sheet to the second side. Thereafter, the sheet passes through a conveying path 317 and is conveyed again to the conveying path 303. A secondary transfer unit 309 transfers an image onto a second surface of the sheet.

[0031] Inserter The inserter 108 includes an inserter tray 321. An insertion sheet stacked on the inserter tray 321 is conveyed along a conveying path 322 and delivered to a conveying path 323. This allows the insertion sheet to be inserted at an arbitrary position in a series of sheets conveyed from the image forming device 107. The conveying path 323 conveys the sheet to a subsequent device (inspection device 109).

[0032] Inspection equipment The sheet that has passed through the inserter 108 is conveyed to the inspection device 109. The CIS 331 is disposed above the conveying path 333 and reads one side of the sheet. The CIS 332 is disposed below the conveying path 333 and reads the other side of the sheet. The CISs 331 and 332 may be replaced with line scan cameras. When the sheet conveyed to the conveying path 333 reaches a predetermined position, the inspection device 109 reads an image of the sheet using the CISs 331 and 332 and judges whether the image meets the pass criteria. The display 241 displays the inspection result and the like. The CPU 238 judges the timing when the sheet reaches a predetermined position (reading start timing) based on the timing when the sheet sensor 334 detects the leading edge of the sheet (detection timing). Usually, the difference between the detection timing and the reading start timing is a fixed value.

[0033] The inspection device 109 inspects an image (inspection target) formed on a sheet according to a preset inspection item. That is, the inspection device 109 compares the preset correct answer image data with the image data of the inspection target. The image data comparison method includes, for example, a comparison of pixel values ​​for each image position, a comparison of the position of an object extracted by edge detection, and a comparison of character data extracted by OCR (Optical Character Recognition). The inspection items include, for example, a print position, a color tone of an image, an image density, a streak or blur, a black spot, and a print void. The image inspection may be performed as follows. For example, the inspection content may be "position deviation". The inspection device 109 may determine that the image is passed if the amount of deviation between the position of the correct answer image and the position of the inspection image is equal to or less than a judgment threshold. The inspection device 109 may determine that the image is failed if the amount of deviation exceeds the judgment threshold. The inspection content may be set to "black spot". The inspection device 109 may determine that the image is passed if the size of a black spot that is not in the correct answer image and is in the inspection image is equal to or less than a judgment threshold. The inspection device 109 may determine that the image is unacceptable if the size of the black dot exceeds the judgment threshold. In this embodiment, the inspection contents are described as "misalignment" and "black dot", but this is merely an example. In this embodiment, when the inspection content is "misalignment", the relative position between the correct image and the inspection image is inspected, but this is merely an example. For example, the absolute position of the inspection image with respect to the edge of the sheet may be inspected. In this case, if the distance between the absolute position of the correct image and the absolute position of the inspection image is equal to or less than the judgment threshold, the image is determined to be acceptable. If the distance exceeds the judgment threshold, the image is determined to be unacceptable.

[0034] ●Large capacity stacker The large-capacity stacker 110 has a stack tray 341 as a tray for stacking sheets. A transport path 342 transports the sheet that has passed through the inspection device 109 to a transport path 344. The transport path 344 transports the sheet to a transport path 345. The transport path 345 transports the sheet to the stack tray 341. As a result, the sheet is stacked on the stack tray 341.

[0035] The large-capacity stacker 110 has an escape tray 346 as a discharge tray. The escape tray 346 is a tray onto which sheets that have been determined to be unacceptable by the inspection device 109 are discharged. When a sheet is discharged onto the escape tray 346, the conveying path 344 conveys the sheet to a conveying path 347. The conveying path 347 conveys the sheet to the escape tray 346.

[0036] When the sheet is to be conveyed to the finisher 111 connected to the rear stage of the large-capacity stacker 110, the conveying path 344 conveys the sheet to the conveying path 348. The conveying path 348 conveys the sheet to the finisher 111.

[0037] The inversion unit 349 is a transport path for inverting the front and back of a sheet. By inverting the front and back of a sheet, face-down ejection or face-up ejection can be realized. Face-down ejection means that in a single-sided printing mode, a sheet is ejected so that the image-formed side faces downward. Face-up ejection means that in a double-sided printing mode, a sheet is ejected so that the first side on which an image is formed faces upward. This allows the image-formed side of the sheet to face the direction intended by the user. If the sheet is transported to the escape tray 346 or the finisher 111, the inversion unit 349 does not need to invert the sheet.

[0038] Finisher The finisher 111 performs finishing processing on the conveyed sheets according to a function designated by the user. The post-processing unit 253 includes a staple unit 355 that performs stapling (one-place or two-place stapling) or punching (two or three holes) and a saddle stitching unit 356 that performs saddle stitching. The finisher 111 has two discharge trays 351 and 352. The conveying path 353 discharges the sheets received from the large-capacity stacker 110 to the discharge tray 351. However, the conveying path 353 cannot perform finishing processing such as stapling. When finishing processing such as stapling is required, the conveying path 354 conveys the sheets received from the large-capacity stacker 110 to the staple unit 355. The staple unit 355 performs the finishing processing (punching or stapling) designated by the user and discharges the sheets to the discharge tray 352. The discharge trays 351 and 352 can be raised and lowered. The CPU 250 may lower the discharge tray 351 and discharge the sheets to which the finishing process has been applied by the staple unit 355 onto the discharge tray 351. When saddle stitching is specified, the saddle stitching unit 356 staples the sheets in the center, folds the sheets in half, and conveys them along a conveying path 357. The conveying path 357 discharges the sheets onto a bookbinding tray 358. The bookbinding tray 358 has a belt conveyor, and conveys the bound bundle loaded on the bookbinding tray 358 to the left side of FIG.

[0039] (4) Flowchart (Registration process of correct image data) External Controller 4A shows a process executed by the CPU 208 of the external controller 102 according to a program. Here, it is assumed that the PC 103 transmits a print instruction for the correct image to the external controller 102 in order to register the correct image data in the inspection device 109.

[0040] In S401, the CPU 208 determines whether or not a print instruction for the correct image has been received from the PC 103. When a print instruction has been received, the CPU 208 advances the process from S401 to S402. In S402, the CPU 208 transmits a print job for the correct image to the image forming apparatus 107.

[0041] Image forming equipment 4B shows a process executed in accordance with a program by the CPU 222 of the image forming apparatus 107. Here, it is assumed that a print job for a correct image is transmitted from the external controller 102.

[0042] In S411, the CPU 222 determines whether or not a print job has been received from the external controller 102. If a print job has been received, the CPU 222 advances the process from S411 to S412.

[0043] In S412, the CPU 222 controls printing and optional devices according to the print job received from the external controller 102. The print job may include image data of the correct image, identification information of the feeding device that feeds the sheets, and identification information of the tray to which the sheets are discharged. The CPU 222 controls optional devices (the inserter 108, the inspection device 109, the large-capacity stacker 110, and the finisher 111) via the communication cable 254 according to the print job.

[0044] Inspection equipment 5 shows an example of a UI screen 500 displayed on the display 241 when the inspection device 109 is started. UI is an abbreviation for user interface. Message 501 is a message that explains to the user that since no correct answer image data has been registered, registration of correct answer image data is required to start the inspection. If correct answer image data has already been registered, message 501 indicates that the inspection process can be started.

[0045] Registered correct image data is displayed in area 502. In Fig. 5, the correct image data is not registered, so area 502 displays the word "not registered."

[0046] Button 503 is a button for calling a registration screen for correct image data. Button 506 is a button for calling an inspection setting screen. CPU 238 accepts inspection items and inspection levels (conditions for judging as fail or pass) according to the user's inspection purpose via the setting screen. Button 507 is a button for instructing the start of inspection. When button 507 is pressed, inspection device 109 starts inspecting the image of the conveyed sheet.

[0047] FIG. 6 is a diagram showing an example of a registration screen 600 of the correct image data. When the CPU 238 detects the pressing of the button 503, it displays the registration screen 600 on the display 241. The up and down buttons 601 are a setting section for setting the number of sheets to be inspected (the number of sheets per set). When one set is composed of two or more sheets (images or pages), the CPU 238 can register a plurality of correct images. The check box 602 is a setting section for setting the surface to be inspected. Either both sides of the sheet, only the front side, or only the back side is set as the inspection target. In the single-sided printing mode, both sides may be selected as the inspection target in order to inspect that there is no dust on the side on which the image is not printed. In the example of FIG. 6, both sides are selected as the inspection target. The up and down buttons 603 are a setting section for setting the number of read images that are the basis of the correct image data. For example, the CPU 238 reads M sheets to obtain M pieces of image data, and generates the correct image data by superimposing and averaging the M pieces of image data. The registration start button 604 is a button for instructing the start of registration of the correct image data to the CPU 238. When the CPU 238 detects that the registration start button 604 is pressed, it reads the image on the conveyed print sheet and registers the correct image data based on the image.

[0048] 7 shows an example of a UI screen 700 displayed on the display 241 during reading of a correct image started by pressing the registration start button 604. In the UI screen 700, the registration start button 604 is simply changed to a stop button 701. The CPU 238 continues to display the UI screen 700 on the display 241 until reading of the M sheets set by the up and down buttons 601 and 603 is completed. The stop button 701 is a button for instructing the CPU 238 to stop reading of the correct image. When the stop button 701 is pressed, the CPU 238 returns the UI screen 700 to the registration screen 600 without registering the correct image data.

[0049] 8A shows a setting screen 800 that is displayed on the display 241 when the button 506 is operated. The CPU 238 creates environmental settings in accordance with instructions input via the setting screen 800 and stores them in the memory 239.

[0050] The check box 801 is a control object for selecting whether to automatically detect a human face included in the correct image and automatically set an inspection area. The menu 802 is a pull-down menu for selecting the number (upper limit) of faces for which the inspection area is set. The check box 803a is a control object for selecting whether to execute an inspection item (e.g., black spot detection) in the inspection area. Black spots are a group of black pixels that do not exist in the correct image. The menu 804a is a control object for selecting the inspection level of the inspection item (e.g., black spot detection). The inspection level is a parameter that defines the strictness of the inspection item (the standard for determining whether the item is passed). The check box 803b is a control object for selecting whether to execute an inspection item (e.g., streak detection) in the inspection area. A streak is a group of linear defective pixels that do not exist in the correct image. The menu 804b is a control object for selecting the inspection level of the inspection item (e.g., streak detection). The check box 805 is a control object for selecting the process of a rejected product (e.g., discharge to the escape tray 346 / record in a log). When the user presses the OK button 806 , the CPU 238 saves the environmental settings in the memory 239 .

[0051] The preferences described here are preferences that apply when automatic region setting is enabled, and may exist independently of preferences associated with inspection regions that a user manually sets for a ground truth image.

[0052] 8B shows a setting screen 810 that is displayed on display 241 when button 506 is operated. Setting screen 810 is another example of setting screen 800. In place of check box 801, check box 811 is employed.

[0053] A check box 811 is a control object for selecting whether to automatically set an inspection area in the correct answer image. In this case, whether to automatically detect a human face included in the correct answer image may be stored in advance in the memory 239.

[0054] For example, when the check box 811 is checked, a mode is selected in which an inspection area is automatically set for a human face recognized by face recognition processing. When the check box 811 is not checked, a mode is selected in which an inspection area is manually set without executing face recognition processing. Note that face recognition processing may be executed even when the check box 811 is not checked. In this case, a frame may be displayed so as to surround a human face detected by face recognition processing. The user may set the inspection area by touching the frame.

[0055] 8C shows setting screen 820 that is displayed on display 241 when button 506 is operated. Setting screen 820 is another example of setting screen 800. Instead of check box 801, check box 811 and check box 821 are employed.

[0056] A check box 821 is a control object for selecting whether or not to automatically detect a human face. In this case, there are four modes.

[0057] (i) A mode in which a human face is automatically detected and an inspection area is automatically set around the detected face. (ii) A mode in which human faces are not automatically detected, and the inspection area is automatically set based on the results of edge detection, etc. (iii) A mode in which human faces are automatically detected and the inspection area is manually set on the detected face. (iv) A mode in which human faces are not automatically detected and the inspection area is set manually. 9 is a flow chart showing the process of registering the correct image data according to a program by the CPU 238 of the inspection device 109. When the registration start button 604 is pressed, the CPU 238 executes the following process.

[0058] In S901, the CPU 238 acquires print settings from the memory 239. The print settings are set through the registration screen 600, and include, for example, the number of sheets per set, the sides to be read, and the number of images to be read to generate the reference image data. The print settings may also include environment settings through the setting screen 800. The environment settings are settings that are referenced when registering the reference image.

[0059] In S902, the CPU 238 determines whether or not a sheet has been conveyed to the inspection device 109 based on the detection result of the sheet sensor 334. When the sheet sensor 334 detects the leading edge of the sheet, the CPU 238 advances the process from S902 to S903.

[0060] In S903, the CPU 238 reads the sheet using the CIS 331 and the CIS 332. The CPU 238 stores in the memory 239 the read image data generated by reading the sheet.

[0061] In S904, the CPU 238 converts the resolution of the read image data. There are resolutions suitable for comparing the image to be inspected with the correct image. For example, a low resolution is advantageous for increasing the inspection speed. When a precise inspection is required, a high resolution is advantageous. The appropriate resolution may be selected by the user. When a high resolution is selected, the CPU 238 may skip the resolution conversion.

[0062] In S905, the CPU 238 removes noise from the read image data. Noise will be included in the read image data if paper dust or the like is attached to the CIS 331, 332. Therefore, the CPU 238 removes noise from the read image data by performing morphological conversion or the like.

[0063] 10 is a diagram for explaining a morphological transformation in schematic form. If paper dust is attached to the CIS 331, 332 or the sheet, a large amount of noise 1005 is included in the read image 1001. The CPU 238 shrinks the read image 1001 to generate a shrunken image 1002. This removes small noise 1005. The CPU 238 performs an expansion process on the shrunken image 1002 to generate an image 1003. This removes the noise 1005 while maintaining the original image formed on the sheet.

[0064] In S906, the CPU 238 determines whether the reading of the sheets is complete. For example, the CPU 238 compares the number of sheets included in the print settings with the number of sheets that have been read so far to determine whether the reading is complete. If the reading is not complete, the CPU 238 advances the process from S906 to S902 and starts reading the next sheet. If the reading is complete, the CPU 238 advances the process from S906 to S907.

[0065] In S907, the CPU 238 generates a preview image for displaying a preview of the read image data acquired from the sheet on the display 241.

[0066] In S908, the CPU 238 displays the preview image and the UI screen on the display 241.

[0067] FIG. 11 is a diagram showing an example of a UI screen 1100. An area 1101 is an area for displaying a preview image. When n sheets have been read, the CPU 238 detects a user operation on a switching button 1102 and switches the preview image displayed in the area 1101. The switching button 1103 is a button for switching between a preview image of the front side of the sheet and a preview image of the back side of the sheet. Each time the CPU 238 detects a user operation on the switching button 1103, the CPU 238 switches between the preview image of the front side of the sheet and the preview image of the back side of the sheet. The switching button 1103 is enabled when inspection is performed on both sides of the sheet.

[0068] The enlargement / reduction button 1104 is a button for enlarging or reducing the preview image displayed in the area 1101. To check whether dust and streaks are present in the scanned image, the user can enlarge or reduce the image. The switching buttons 1102 and 1103 and the enlargement / reduction button 1104 are merely examples. The CPU 238 may detect a gesture operation such as a flick, pinch, or swipe, and switch and enlarge or reduce the image in response to the gesture operation. In this case, the operation unit 242 functions as a touch detection sensor mounted on the display 241.

[0069] A button 1105 is a button for instructing the CPU 238 to use the original image of the preview image displayed in the area 1101 as a candidate image for the correct image data.

[0070] Button 1106 is a button for explicitly instructing CPU 238 not to use the original image of the preview image displayed in area 1101 as a candidate image for the correct answer image data. CPU 238 discards the original image of the preview image for which button 1106 is pressed, and does not use it to obtain the correct answer image data.

[0071] The use all button 1107 is a button for instructing the CPU 238 to use all of the acquired images collectively to acquire the correct answer image data. On the other hand, the cancel button 1108 is a button for instructing the CPU 238 to discard all of the acquired images and not use them to acquire the correct answer image data.

[0072] When either the use all button 1107 or the cancel button 1108 is pressed, or the use all images button 1105 or the do not use button 1106 is pressed, the CPU 238 determines that the selection of the original images is complete.

[0073] In S909, CPU 238 determines whether selection of correct images (candidate images) has been completed for all scanned images. If selection of correct images has been completed, CPU 238 advances the process to S911. On the other hand, the number of candidate images may be insufficient because button 1106 has been pressed for some of the candidate images. In this case, selection of correct images has not been completed. Thus, if selection of correct images has not been completed, CPU 238 advances the process to S910.

[0074] In S910, CPU 238 inquires of the user as to whether or not to acquire additional images. If it is selected to acquire additional images, CPU 238 advances the process to S901 and acquires the additional images. On the other hand, if it is selected not to acquire additional images, CPU 238 advances the process to S911.

[0075] In S911, the CPU 238 reads image data of the candidate images from the memory 239 and generates the correct answer image data. For example, the CPU 238 superimposes and averages the image data of the multiple candidate images to generate the correct answer image data. The correct answer image data is stored in the memory 239.

[0076] In S912, the CPU 238 determines whether or not to register the correct image data based on the result of the inquiry to the user. For example, the CPU 238 displays the correct image data on the display 241 and inquires the user whether or not to register it as correct image data. When the user instructs to register the correct image data, the CPU 238 advances the process to S913. When the user rejects the registration of the correct image data, the CPU 238 ends the registration process.

[0077] In S913, the CPU 238 determines whether the automatic region setting is enabled based on the environment settings stored in the memory 239. As described with reference to Fig. 8A, if the check box 801 is checked, the CPU 238 determines that the automatic region setting is enabled and advances the process to S914. If the check box 801 is not checked, the CPU 238 advances the process to S920 to perform manual setting of the inspection region.

[0078] In S914, the CPU 238 detects human faces from the correct answer image data based on the environment settings. If an upper limit number is set by the environment settings, the CPU 238 detects a number of faces that does not exceed the upper limit number. For example, the CPU 238 calculates the area of ​​the detected faces and detects a number of faces that does not exceed the upper limit number in descending order of area. Note that if an upper limit number is not set, all faces are detected.

[0079] In step S915, the CPU 238 sets an inspection area for the detected face based on the environment settings. Each inspection area is associated with an inspection item and an inspection level included in the environment settings.

[0080] In S920, the CPU 238 manually sets the inspection area. For example, the CPU 238 displays the correct answer image data on the display 241, and sets the inspection area based on a user's instruction input through the operation unit 242. Note that the CPU 238 may execute manual setting when an inspection area that has already been automatically set exists, but an inspection area is to be manually added. The CPU 238 may also execute manual setting to delete or move an inspection area that has already been automatically set, or to change the inspection level. If the user does not set a new inspection area, the CPU 238 ends the registration process of the correct answer image data.

[0081] In addition, in S915, the CPU 238 may set an inspection area for the detected face based on the environment setting, and then display a correct answer image including the set inspection area (e.g., area 1303 in FIG. 13) on the display 241. This allows the user to confirm the inspection area and the correct answer image.

[0082] ● Option processing 12 is a flow chart showing optional processing that is executed after the correct image data is acquired. The CPU 238 executes the following processing according to a program.

[0083] In S1201, the CPU 238 displays on the display 241 an addition / deletion UI for adding or deleting the correct image data.

[0084] FIG. 13 shows an example of the add / delete UI 1300. A message 1301 indicates that the correct image data has been registered. A message 1302 indicates that an inspection area has already been set for the correct image data. An area 1303 displays a correct image corresponding to the correct image data. Here, the correct image data is image data created by superimposing and averaging a plurality of (e.g., three) pieces of image data obtained by reading with the CIS 331 and 332. In this example, the inspection area 1313 and the inspection area 1315 are each surrounded by a frame so that the user can see that the inspection area 1313 and the inspection area 1315 have been set for the correct image. The user can remove the inspection area 1313 from the inspection target by touching the inspection area 1313. That is, the user can check the inspection area automatically set by face detection, and remove the inspection area from the inspection target if the inspection area is not necessary.

[0085] The clear button 1304 is a button for instructing the CPU 238 to delete (clear) the correct image data registered in the memory 239. The add button 1305 is a button for instructing the CPU 238 to register additional correct image data. When some scanned images are discarded (set as unused) via the setting screen 800, a correct image derived from the scanned images is not created. When the user wishes to obtain an additional correct image, the user presses this add button 1305. When the add button 1305 is pressed, the CPU 238 displays an additional UI on the display 241.

[0086] FIG. 14 shows an example of an addition UI 1400. A designation button 1401 is a button for designating a page to be added as the correct image data. An addition button 1402 is a button for instructing the CPU 238 to individually add the page designated by the designation button 1401. An addition button 1403 is a button for instructing the CPU 238 to add all pages at once. A message 1404 indicates the page to be read. A setting section 1405 is a control object for setting how many images to read for each designated page. A start button 1406 is a button for causing the CPU 238 to start additional acquisition. When the start button 1406 is pressed, the correct image addition process shown in FIG. 9 is executed.

[0087] An additionally acquired correct answer image is displayed in an area 1303 in FIG. 13. Here, an inspection area 1313 is an inspection area that is automatically set based on a face recognition result. An inspection area 1315 is an inspection area that is manually set by a user's operation of the operation unit 242 (e.g., dragging a mouse, touching a touch detection panel). The inspection areas 1313 and 1315 are displayed so as to be visually distinguishable from each other. For example, the inspection area 1313 may be displayed with a blue dotted frame. The inspection area 1315 may be displayed with a green dotted frame. The inspection items and inspection levels may be set independently for the inspection area 1313 and the inspection area 1315. The setting unit 1306 is a control object that accepts the setting of the inspection item and the inspection level associated with the inspection area 1315. The setting unit 1307 is a control object that accepts the setting of the inspection item and the inspection level associated with the inspection area 1313. For example, the setting of the inspection item may be realized by checking / unchecking a check box. The inspection level may be set by the up / down buttons.

[0088] In FIG. 13, among the multiple faces detected based on the environment settings previously set through the setting screen 800, the inspection area is automatically set for three faces. For example, the areas of the multiple faces are compared, the evaluation value of the face is determined according to the area, and the inspection area is set for the face with the high evaluation value. However, this is only one example. The CPU 238 may analyze the expression of the detected face to calculate the evaluation value (degree of smile), and set the inspection area by giving priority to the face with the high evaluation value. Not inspecting the face with low priority means that image defects existing in the area with low priority are allowed. This improves the yield of the deliverable (printed matter). For example, the inspection area is not set for a face (e.g., an audience member) that happens to be reflected as the background of the subject of the document (e.g., a singer).

[0089] Returning to the description of Fig. 12, in S1202, the CPU 238 determines whether or not to clear the correct image. For example, when the clear button 1304 is pressed, the CPU 238 advances the process to S1203. When it is not instructed to clear the correct image, the CPU 238 advances the process to S1204.

[0090] In S1203 , the CPU 238 deletes the image data of the correct image (correct image data) displayed in the area 1303 from the memory 239 .

[0091] In S1204, the CPU 238 determines whether or not to add a correct answer image. For example, when the add button 1305 is pressed, the CPU 238 advances the process to S1205. When an instruction to additionally register a correct answer image is not given, the CPU 238 advances the process to S1211.

[0092] In S1205, the CPU 238 displays the additional UI 1400 on the display 241.

[0093] In S1206, the CPU 238 determines whether or not individual addition of a correct image has been instructed. For example, when an addition page is specified, the Add button 1402 is pressed, and the Start button 1406 is pressed, the CPU 238 advances the process to S1207. When individual addition has not been instructed, the CPU 238 advances the process to S1208.

[0094] In S1207, the CPU 238 executes individual addition of the correct image data for the specified page. The user instructs the image forming apparatus 107 to print the specified page. After that, the registration process shown in FIG. 9 is executed.

[0095] In S1208, the CPU 238 determines whether or not a command to add all the correct images at once has been issued. For example, when the add button 1403 is pressed and the start button 1406 is pressed, the CPU 238 advances the process to S1209. When a command to add all the correct images at once has not been issued, the CPU 238 advances the process to S1211.

[0096] In S1209, the CPU 238 executes batch addition of the correct image data for all pages. The user instructs the image forming apparatus 107 to print all pages. After that, the registration process shown in FIG. 9 is executed.

[0097] In S1210, the CPU 238 displays an add / delete UI 1300 on the display 241.

[0098] In S1211, the CPU 238 determines whether or not a change in the inspection conditions has been instructed via the addition / deletion UI 1300. If a change in the inspection conditions has been instructed, the CPU 238 advances the process to S1212. If a change in the inspection conditions has not been instructed, the CPU 238 advances the process to S1213.

[0099] In S1212, the CPU 238 changes the inspection conditions (e.g., inspection level, inspection item, inspection area) according to a user instruction input from the operation unit 242. The changed inspection conditions are associated with the correct image data displayed in the area 1303 and stored in the memory 239.

[0100] In S1213, the CPU 238 determines whether or not an instruction has been given to close the addition / deletion UI 1300. If an instruction has been given via the operation unit 242 to close the addition / deletion UI 1300, the CPU 238 advances the process to S1214. If an instruction has not been given to close the addition / deletion UI 1300, the CPU 238 advances the process to S1202.

[0101] In S1214, the CPU 238 closes the add / delete UI 1300.

[0102] (5) Imaging tests 15 shows an example of an inspection job setting screen 1500 displayed on the display 212 of the external controller 102. The CPU 208 of the external controller 102 instructs the image forming system 101 to transport the sheet of the correct image and the sheet to be inspected to the inspection device 109.

[0103] The setting unit 1501 is a control object for setting the number of copies to be printed (e.g., 1000 copies) to be inspected. The setting unit 1503 is a control object for setting the destination of sheets determined to be acceptable (e.g., stack tray 341) and the destination of sheets determined to be unacceptable (e.g., escape tray 346). The destination of acceptable and unacceptable products may be the same. In this case, the user checks the list of inspection results displayed on the displays 212, 225, and 241, and manually removes the sheets that have been rejected. For example, the image forming system 101 may, based on the inspection results provided by the inspection device 109, eject acceptable and unacceptable sheets to the same tray by shifting them in a direction perpendicular to the conveying direction. This makes it easier to remove the unacceptable products.

[0104] Button 1504 is a button for specifying the number of copies of the correct image to be printed. When the registration start button 604 is pressed, the inspection device 109 is instructed to start registering the correct image data. Thereafter, the user sets the number of copies to be printed with button 1504, and instructs the start of printing of the correct image with button 1505. The image forming device 107 prints the correct image based on the instruction from the external controller 102. The inspection device 109 executes reading of the correct image based on the instruction from the external controller 102.

[0105] When the registration start button 604 is pressed, the inspection device 109 may instruct the external controller 102 to print N correct images via the communication cable 254 and the internal LAN 105. Similarly, when the start button 1406 is pressed, the inspection device 109 may instruct the external controller 102 to print specific / all pages.

[0106] The print start button 1508 is a button for instructing the image forming system 101 to start printing the inspection target. When the print start button 1508 is pressed, the external controller 102 transmits an inspection job based on the printing conditions set via the setting screen 1500 to the image forming apparatus 107.

[0107] After instructing the inspection device 109 to start inspection with button 507, the user instructs the external controller 102 to start printing the object to be inspected with print start button 1508. The external controller 102 transmits print data to the image forming device 107 and instructs the image forming device 107 to transport the printed sheet to the inspection device 109. When the inspection device 109 detects that the sheet has been transported, it reads the image of the sheet to create inspection image data, compares it with the correct image data, and judges whether the printing is acceptable or not.

[0108] A cancel button 1509 is a button for instructing the CPU 208 to cancel the display of the inspection job setting screen 1500 without printing.

[0109] When the print start button 1508 is pressed to instruct the start of printing of the inspection target, the external controller 102 may instruct the inspection device 109 to start inspection. In this case, the inspection device 109 may notify the external controller 102 in advance whether or not the correct image data has been registered. If the correct image data has not been registered in the inspection device 109, the external controller 102 may refuse to print the inspection target.

[0110] FIG. 16 is a flowchart showing the inspection process executed by the CPU 238 of the inspection device 109 in accordance with a program.

[0111] In S1601, the CPU 238 determines whether an end instruction for the inspection process has been received from the operation unit 242 or the external controller 102. When the end instruction is received, the CPU 238 ends the series of inspection processes shown in Fig. 16. If the end instruction has not been received, the CPU 238 advances the process to S1602.

[0112] In S1602, the CPU 238 determines whether or not the sheet has arrived at the inspection device 109. For example, the CPU 238 determines whether or not the leading edge of the sheet has been detected based on the detection result of the sheet sensor 334 installed near the entrance of the inspection device 109. When the sheet has arrived at the inspection device 109, the CPU 238 advances the process to S1603.

[0113] In S1603, the CPU 238 reads the sheet by controlling the CIS 331 and the CIS 332. The CPU 238 stores in the memory 239 image data of the inspection target, which is the read result.

[0114] In S1604, the CPU 238 converts the resolution of the image data of the inspection target. There are resolutions suitable for comparing the image of the inspection target with the correct image. For example, a low resolution is advantageous for increasing the inspection speed. A high resolution is advantageous when a precise inspection is required. The user may select which resolution is appropriate. In any case, the resolution of the image data of the inspection target and the resolution of the correct image data must match. If a high resolution is selected, the CPU 238 may skip the resolution conversion.

[0115] In S1605, the CPU 238 removes noise from the image data of the inspection target. Noise will be included in the image data if paper dust or the like is attached to the CIS 331, 332. Therefore, the CPU 238 removes noise from the image data by performing morphological transformation or the like.

[0116] In S1606, the CPU 238 compares the image data of the inspection target with the correct image data. The correct image data is stored in advance in the memory 239. The comparison process is performed according to the inspection area, inspection item, and inspection level associated with the correct image data.

[0117] In S1607, the CPU 238 determines whether the inspection image passes based on the comparison result. If the inspection image meets the pass criteria, the CPU 238 advances the process to S1608. In S1608, the CPU 238 displays on the display 241 that the inspection result is pass.

[0118] In S1609, the CPU 238 instructs the image forming apparatus 107 to discharge the passing sheet to the stack tray 341 of the large capacity stacker 110. Here, the discharge destination is the discharge destination set by the setting unit 1503. Based on the instruction from the inspection apparatus 109, the image forming apparatus 107 instructs the large capacity stacker 110 to discharge the sheet to the stack tray 341. Thereafter, the CPU 238 advances the process to S1601 and performs inspection of the next sheet.

[0119] On the other hand, if the inspection result is a failure in S1607, the CPU 238 advances the process to S1610.

[0120] In S1610, the CPU 238 displays on the display 241 that the inspection result is a failure. In S1611, the CPU 238 instructs the image forming apparatus 107 to discharge the sheet to the escape tray 346 of the large capacity stacker 110. The discharge destination here is the discharge destination set by the setting unit 1503. Based on an instruction from the inspection apparatus 109, the image forming apparatus 107 instructs the large capacity stacker 110 to discharge the sheet to the escape tray 346. Thereafter, the CPU 238 advances the process to S1601 and performs inspection of the next sheet.

[0121] According to this embodiment, the CPU 238 can register correct answer image data and determine pass / fail of the inspection target by comparing the image data of the inspection target with the correct answer image data.

[0122] 17 shows an example of an inspection screen 1700 displayed on the display 241 when the button 507 is pressed. Area 1701 displays the image of the sheet last read by the inspection device 109 (inspection image). Message 1702 indicates whether the inspection image displayed in area 1701 is pass (OK) or fail (NG). The inspection image has been determined to be pass. Area 1704 indicates the number of images in the inspection job that the image (sheet) currently being inspected is.

[0123] The end of examination button 1703 is a button for instructing the end of the examination to the CPU 238. When the end of examination button 1703 is pressed, the CPU 238 displays the UI screen 500 on the display 241.

[0124] FIG. 18 shows an example of an inspection screen 1700 when an inspection image is determined to be a failing image. A message 1702 indicates that the inspection result is a fail. A cause display section 1801 indicates the cause of the fail. In this example, the inspection image displayed in area 1701 has a streak 1805. Therefore, CPU 238 displays in cause display section 1801 that the streak is present in the inspection area as the cause of the fail. A position display section 1802 indicates the position in the inspection image where the cause of the fail exists. In this example, position display section 1802 displays the position of streak 1805.

[0125] According to this embodiment, the CPU 238 detects a face in the correct image and sets an inspection area for the detected face, thereby reducing the user's workload for setting the inspection area.

[0126] (6) CPU functions FIG. 19 shows an example of a function that the CPU 238 of the inspection device 109 realizes according to a program. The registration control unit 1901 controls the registration of a correct image. For example, the registration control unit 1901 displays a UI on the display 241 and receives instructions from a user through the UI. The image processing unit 1902 applies various image processing to image data acquired by the CIS 331 and 332. The conversion unit 1911 converts the resolution of the image data. The removal unit 1912 reduces noise contained in the image data output from the conversion unit 1911. The preview unit 1913 reduces the image data output from the removal unit 1912 to generate a preview image. The superimposition averaging unit 1914 performs superimposition and averaging on the image data output from the removal unit 1912. As a result, the superimposition averaging unit 1914 generates correct image data in the registration mode and generates inspection image data in the inspection mode.

[0127] The face recognition unit 1903 analyzes the correct image data and detects a human face. As a method of face detection, for example, there is a method of extracting skin color data from image data and extracting an area determined to be a skin color range as a face area. There is also a method that focuses on facial parts such as eyes, nose, and mouth. Furthermore, there is also a method that uses elliptical shape information focusing on the outline of the face. In this way, this embodiment can adopt any method that can detect a face. The evaluation unit 1904 calculates an evaluation value of the face recognized by the face recognition unit 1903. The evaluation value includes the area of ​​the face, the facial expression, or the distance from the subject that is the main subject. The face recognition unit 1903 may add two or more individual evaluation values ​​to obtain a sum. The evaluation value may be calculated in the automatic area setting unit 1905. The automatic area setting unit 1905 sets an inspection area for the face recognized by the face recognition unit 1903 based on the environmental conditions set by the condition setting unit 1907 through the setting screen 800 and the evaluation value. An automatic area setting unit 1905 associates an inspection item and an inspection level with the inspection area and stores them in the memory 239. A manual area setting unit 1906 determines an inspection area at an arbitrary position and an inspection item and inspection level associated with the inspection area based on a user instruction input through the operation unit 242. The position, inspection item, and inspection level of the inspection area associated with the correct image data are stored in the memory 239 as inspection conditions.

[0128] The inspection control unit 1921 controls the inspection process shown in Fig. 16. The inspection unit 1922 applies inspection conditions to the inspection image data generated by the image processing unit 1902 and the correct image data read from the memory 239, and judges whether the inspection image data passes or fails. The result output unit 1923 displays the inspection result on the display 241 and transmits the inspection result to the inspection control unit 1921 and the external controller 102. The inspection control unit 1921 sets the sheet discharge destination to the image forming apparatus 107 according to the inspection result.

[0129] (7) Technical ideas derived from the examples [Item 1] The CIS 331 and 332 are examples of image sensors that read a sheet on which a correct image is printed and obtain first read data. The CPU 238 executes various operations according to a program. For example, the CPU 238 may execute an operation of accepting a selection from a first mode in which an inspection area is automatically set and a second mode in which an inspection area is manually set, an operation of reading a sheet on which a correct image is printed by an image sensor and obtaining first read data, a generation operation of generating correct data based on the first read data, an operation of executing a face recognition process on the correct data when the first mode is selected and setting an inspection area based on the recognition result of the face recognition process, an operation of accepting a designation of an inspection area for the correct data when the second mode is selected, and an inspection operation of comparing second read data obtained by reading a sheet on which an image to be inspected is printed by an image sensor with the correct data in the inspection area to inspect whether the sheet on which the image to be inspected is printed is a pass product.

[0130] The inspection device 109 is an example of an image processing device. The image processing device may be realized by the PC 103. The user selects the first mode, and the inspection area is automatically set. This reduces the burden on the user in image inspection. On the other hand, there are users who wish to set the inspection area manually. In this case, the user can manually set the inspection area by selecting the second mode.

[0131] [Item 2] An inspection level may be set for each inspection area. This allows the inspection sophistication to be changed for each inspection area. For example, a high inspection level may be set for a face that is the subject of the image, and a low inspection level may be set for a face located in the background. This may improve the inspection yield.

[0132] [Item 3] 13, the CPU 238 may set each of the multiple faces as an inspection target, or may set some of the multiple faces as non-inspection targets. Note that setting some faces as non-inspection targets includes not setting some faces as inspection targets.

[0133] [Item 4] 13, by displaying the face set as the inspection target, the user can check whether the automatic setting of the inspection area is working properly. Furthermore, the CPU 238 may delete the automatically set inspection area, change the size of the inspection area, or move the inspection area in response to a user operation input from the operation unit 242. By allowing the user to modify the inspection area in this way, an inspection that is more in line with the user's wishes can be performed.

[0134] [Item 5] 13, a frame may be added to a face set as an inspection target, and a frame may not be added to a face not set as an inspection target, allowing the user to visually distinguish between a face set as an inspection target and a face not set as an inspection target.

[0135] [Item 6] A frame may be displayed around the face set as the inspection target in the correct answer data, but an indicator or mark other than the frame may also be displayed.

[0136] [Item 7] An evaluation value may be calculated for each of the recognized faces. In this case, a face to be inspected may be selected based on the evaluation values ​​of each of the recognized faces.

[0137] [Item 8] The setting operation may be such that, from among a plurality of recognized faces, a face with a high evaluation value is preferentially selected as an inspection target.

[0138] This will enable the inspection to be carried out efficiently and will also shorten the inspection time.

[0139] [Item 9] Item 7. The image processing device according to item 7, The evaluation value may include the area of ​​the recognized face. In this case, a face having a larger area may be preferentially selected as an object to be examined.

[0140] A face with a large surface area is more likely to be the subject of a photograph. On the other hand, a face with a small surface area is more likely to be merely background. Therefore, by focusing on the surface area of ​​a face, it will be possible to accurately extract faces that require examination.

[0141] [Item 10] Of the multiple faces, a predetermined number of faces having a relatively large face area may be selected as inspection targets.

[0142] In this manner, a predetermined number of faces may be selected in descending order of evaluation value. Limiting the number of faces to be inspected improves inspection speed.

[0143] [Item 11] Item 7. The image processing device according to item 7, An evaluation value of the facial expression of each of the extracted faces may be calculated. Of the recognized faces, a face with a high evaluation value may be preferentially selected as an inspection target.

[0144] In this way, facial expressions can be used as a criterion for determining whether a face is the subject of a photo. Therefore, by focusing on the evaluation value of facial expressions, it may be possible to accurately extract faces that require examination.

[0145] [Item 12] A smiling face may be calculated to have a higher evaluation value, and a non-smiling face may be calculated to have a lower evaluation value.

[0146] Empirically, smiling faces are more likely to be the subject of the study, so by assigning a higher evaluation value to smiling faces and a lower evaluation value to non-smiling faces, it will be possible to accurately extract faces that require examination.

[0147] [Item 13] An area evaluation value and an expression evaluation value may be calculated for each of the extracted faces. Of the recognized faces, a face having a high sum of an area evaluation value and an expression evaluation value may be preferentially selected as an inspection target.

[0148] In this way, the CPU 238 may add up the evaluation value of the area and the evaluation value of the facial expression to obtain a sum, and preferentially select as the inspection target a face having a high sum of the evaluation values.

[0149] [Item 14] The large-capacity stacker 110 and the finisher 111 are examples of a discharge device that changes the discharge destination of a sheet according to the inspection result of an inspection device. The discharge device discharges a sheet to one of a plurality of discharge ports according to the inspection result output by the inspection device.

[0150] [Item 15] The stack tray 341 is an example of a first discharge tray that discharges sheets that have been determined to be acceptable by the inspection device, and the escape tray 346 is an example of a second discharge tray that discharges sheets that have been determined to be unacceptable by the inspection device.

[0151] This saves the user the trouble of sorting out acceptable and unacceptable products.

[0152] [Item 16] Passed and rejected products may be discharged onto an escape tray 346. In this case, the displays 241 and 225 may display a list of the inspection results of the inspection device.

[0153] In this way, when passed and rejected products are discharged onto the same tray, the user can refer to the list of inspection results to extract and discard the rejected products.

[0154] [Item 17] An imaging method is also provided.

[0155] [Item 18] Programs are also provided.

[0156] [others] According to the above example, an area including a face is detected as an inspection area by face recognition processing. However, the CPU 238 may detect an area including content such as a photo, a figure, or a character, not limited to a face. Note that a face, a photo, a figure, or a character may be called a content. In this case, the face area described above may be called a content area. That is, the CPU 238 may automatically set a content area in the reference image, or may accept manual setting of a content area in the reference image. Furthermore, the CPU 238 may display a setting screen for setting an inspection level for the set content area on the display 241. The CPU 238 may detect a content area from a read image generated from a sheet to be inspected, and inspect the content area according to the set inspection level.

[0157] The face recognition unit 1903 functions as a content area detection unit.

[0158] 8A to 8C, the display 241 may display a screen for selecting whether or not to enable setting of an inspection level corresponding to an area of ​​the content detected by the detection unit. Alternatively, the display 241 may display a screen for selecting whether or not to execute detection of the area of ​​the content by the detection unit.

[0159] The user may select not to enable setting of the inspection level corresponding to the detected content area, in which case the CPU 238 may accept, via the operation unit 242, the setting of the area for which the inspection level is to be set and the setting of the inspection level for that area.

[0160] A user may select to enable setting of an inspection level corresponding to a detected content area. In this case, the CPU 238 may also receive, via the operation unit 242, the setting of an area for which an inspection level is to be set and the setting of the inspection level for that area.

[0161] When a content area is automatically detected, CPU 238 may receive, via operation unit 242, a user operation to cancel the detected content area.

[0162] The process relating to the setting of the inspection device 109 and the process relating to the inspection may be executed by the PC 103 .

[0163] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0164] 109...Inspection equipment, 331, 332...CIS, 238...CPU

Claims

1. A reading means for reading an image on a sheet, A detection means for detecting the content area in a reference image used for inspecting a read image obtained by the reading means reading an image on the sheet, A display means that displays a setting screen for setting an inspection level that indicates the criteria for inspecting the read image and corresponds to the area of ​​the content detected by the detection means, An inspection means that inspects the read image corresponding to the area of ​​the content at the inspection level set on the setting screen, based on the read image and the reference image. It has, The inspection system is characterized in that the display means displays a screen for selecting whether or not to perform detection of the content area by the detection means.

2. The inspection system according to claim 1, characterized in that the area of ​​the content is the area of ​​the face.

3. The inspection system according to claim 1, characterized in that, if the display means is selected not to enable detection of the content area, it accepts user settings for the area where the inspection level is set and the inspection level for that area.

4. The inspection system according to claim 1, characterized in that, when the display means is selected to enable detection of the content area, it accepts user settings for the area to which the inspection level is set and the inspection level for said area.

5. The inspection system according to claim 1, characterized in that, when the display means is selected to enable detection of the content area, it accepts an operation to remove the content area detected by the detection means from the area for which the inspection level is set.

6. An image forming apparatus that forms an image on a sheet, A reading device that reads the image on the sheet being transported from the image forming apparatus, A detection means for detecting the content area in a reference image used for inspecting a read image obtained by the reading device reading an image on the sheet, A display means that displays a setting screen for setting an inspection level that indicates the criteria for inspecting the read image and corresponds to the area of ​​the content detected by the detection means, An inspection means that inspects the read image corresponding to the area of ​​the content at the inspection level set on the setting screen, based on the read image and the reference image. It has, The image forming system is characterized in that the display means displays a screen for selecting whether or not to perform detection of the content area by the detection means.

Images