Image inspection device and image inspection program

Abstract

This provides an image inspection device and image inspection program that easily obtain inspection results that reflect changes in user evaluations. [Solution] An image inspection device 10 generates an inspection report showing the inspection result of performing an inspection based on a set first inspection level to determine whether or not a difference region identified from a difference image based on a comparison between a read image generated by reading a recording medium on which an image has been formed and a reference image is abnormal, and the device includes a report generation unit 514 that controls the device to store the inspection result from the set first inspection level and the inspection result from a second inspection level, which has a different inspection result from the inspection from the first inspection level, in association with the inspection report.

Description

Technical Field

[0001] The present invention relates to an image inspection apparatus and an image inspection program.

Background Art

[0002] Conventionally, the quality of printed matter has been inspected by comparing a reference image with an inspection image obtained by reading the printed matter to be inspected.

[0003] In addition, since the allowable range of abnormalities that can be tolerated by a user varies depending on the use and purpose of the printed matter, a technique for facilitating the setting of detection parameters as an allowable range is disclosed in Patent Document 1.

[0004] In the image forming system disclosed in Patent Document 1, an abnormality is detected based on preset detection parameters and displayed to the user. By receiving an input from the user to change the evaluation to normal with respect to the detection result of the abnormality, the image forming apparatus changes the evaluation of the abnormality and determines and sets the detection parameters of the abnormality so as not to detect this changed abnormality.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the image forming system disclosed in Patent Document 1, it is possible for the user to adjust the detection parameters to a more lenient direction, such as re-evaluating abnormalities that were previously judged as abnormal as normal, but it is difficult to adjust them to a more strict direction. Furthermore, in cases where an inspection report is attached to the printed material after delivery to the customer, if the detection parameters are changed to a more lenient or strict direction, the previous inspection results cannot be used, and it is necessary to perform the inspection again and generate a new inspection report.

[0007] This invention has been made in view of the above circumstances, and aims to provide an image inspection device and an image inspection program that can easily reflect changes in the user's evaluation in the inspection results for abnormalities in printed materials, without requiring re-inspection. [Means for solving the problem]

[0008] The above objectives of the present invention are achieved by the following means.

[0009] (1) An image inspection device that generates an inspection report showing the inspection result of performing an inspection based on a set first inspection level to determine whether or not a difference region identified from a difference image based on a comparison between a read image generated by reading a recording medium on which an image has been formed and a reference image is abnormal, An image inspection apparatus comprising a report generation unit that controls the storage of the inspection results obtained by the set first inspection level and the inspection results obtained by a second inspection level, which have different inspection results from those obtained by the first inspection level, in association with the inspection report.

[0010] (2) The image inspection apparatus according to (1) above, comprising a level determination unit that divides the difference region into multiple determination levels based on a preset level threshold.

[0011] (3) The image inspection apparatus according to (2) above, wherein the report generation unit stores all difference regions identified by comparison in association with the determination level determined by the level determination unit.

[0012] (4) Equipped with an inspection level setting unit for setting the inspection level, The image inspection apparatus according to (2) above, wherein the level determination unit compares the determination level of the difference region that has been divided into levels with a set inspection level to perform the inspection.

[0013] (5) The image inspection apparatus according to (1) above, comprising an inspection level setting unit that switches the first inspection level to the second inspection level according to a user's specification.

[0014] (6) With the switch to the second inspection level, The image inspection apparatus described in (5) above, which newly generates an inspection report showing the inspection result of performing an inspection based on the second inspection level to determine whether or not the difference region is abnormal.

[0015] (7) An image inspection program that is executed on an image inspection device, Step (a) is to generate an inspection report showing the inspection results, which is performed based on a set first inspection level to determine whether or not the difference region identified from the difference image, which is generated by reading the recording medium on which the image is formed, is abnormal, based on a set first inspection level. An image inspection program for causing an image inspection device to perform a process including (b) storing, in association with the inspection report, the inspection results obtained by a set first inspection level and the inspection results obtained by a second inspection level which differ from the inspection results obtained by the first inspection level.

[0016] (8) The image inspection program according to (7) above, wherein step (a) includes step (a1) of classifying the difference region into multiple judgment levels according to a predetermined criterion.

[0017] (9) In the above-mentioned step (b), all the differential regions identified by comparison are stored in association with the determination level determined in the above-mentioned step (a1). The image inspection program according to (8) above.

[0018] (10) It has a step (c) of setting an inspection level. By comparing the determination level of the differential region leveled in the above-mentioned step (a1) with the inspection level set in the above-mentioned step (c), the above-mentioned (8) The image inspection program described above.

[0019] (11) The image inspection program according to (7) above, which has a step (d) of switching the first inspection level to the second inspection level according to a designation from a user.

[0020] (12) Along with the switching to the second inspection level in the above-mentioned step (d). In the above-mentioned step (a), newly, whether the differential region is abnormal or not is determined based on the second inspection level. An image inspection program according to (11) above that generates an inspection report showing the inspection result of the executed inspection.

Effect of the Invention

[0021] The image inspection apparatus according to the present invention reads a recording medium on which an image is formed, and determines whether a differential region specified from a differential image based on comparison with a reference image is abnormal or not. An image inspection apparatus that generates an inspection report showing the inspection result of the inspection executed based on the set first inspection level, and controls the inspection result according to the set first inspection level and the inspection result according to the second inspection level, the inspection result of which is different from the inspection according to the first inspection level, to be stored in association with the inspection report. As a result, a change in evaluation by the user can be easily reflected in the inspection result.

Brief Description of the Drawings

[0022] The advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings. However, these are for illustrative purposes only and are not intended to limit the present invention. [Figure 1] It is a diagram showing a schematic configuration of a printing system 1000 including an image inspection device 10 according to a first embodiment. [Figure 2] It is a block diagram showing the hardware configuration of the image inspection device 10. [Figure 3] It is a functional block diagram showing the functions of a control unit 310 and an image inspection control unit 351. [Figure 4A] It is an example of a preset level threshold. [Figure 4B] It is a table showing the correspondence between abnormal / normal at the determination level and the inspection level. [Figure 5] It is a block diagram showing the hardware configuration of the terminal device 40. [Figure 6] It is a functional block diagram when the terminal device 40b in another embodiment functions as an image inspection device. [Figure 7A] It is a flowchart showing an image inspection process. [Figure 7B] It is a flowchart showing the process performed following FIG. 7A. [Figure 8] It is a diagram showing an example of a difference region list. [Figure 9] It is an example of a chart for setting a stain inspection level referred to when a user sets an inspection level. [Figure 10A] It is an example of a difference region list in which inspection results obtained by inspecting at inspection level 5 are described. [Figure 10B] It is an example of a display screen of an inspection report generated based on the inspection results of FIG. 10A. [Figure 11] It is an example of a setting screen for accepting a change in the setting of an inspection level. [Figure 12A] It is an example of a difference region list in which inspection results obtained by reinspecting each difference region at a second inspection level are described. [Figure 12B]This is an example of how an inspection report generated based on the inspection results list in Figure 12A is displayed. [Figure 13] This is an example of a settings screen that allows users to change the inspection level settings. [Figure 14A] This is an example of a list of difference regions, which describes the test results after each difference region has been re-examined at the second test level. [Figure 14B] This is an example of how an inspection report generated based on the inspection results list in Figure 14A is displayed. [Modes for carrying out the invention]

[0023] Embodiments of the present invention will be described below with reference to the attached drawings. However, the scope of the present invention is not limited to the embodiments disclosed. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. The advantages and features provided by one or more embodiments of the present invention will be fully understood from the detailed description below and the attached drawings. Furthermore, the attached drawings are provided for illustrative purposes only and are not intended to define the scope of the present invention.

[0024] <Printing System Configuration> Figure 1 is a diagram showing the schematic configuration of a printing system 1000 including an image inspection device 10 according to the first embodiment. Figure 2 is a block diagram showing the hardware configuration of the image inspection device 10. Figure 3 is a functional block diagram showing the functions of the control unit 310 and the image inspection control unit 351. Figure 4A is an example of a preset level threshold. Figure 4B is a table showing the correspondence between abnormal / normal in the judgment level and inspection level. Figure 5 is a block diagram showing the hardware configuration of the terminal device 40.

[0025] As shown in Figure 1, the printing system 1000 includes a terminal device 40 and an image inspection device 10. The terminal device 40 and the image inspection device 10 are connected to each other so as to be able to communicate with each other via a communication line 90.

[0026] The terminal device 40 may be, for example, a personal computer, a tablet, or a smartphone. The terminal device 40 has a printer driver installed for converting document data into a print job. The printer driver generates a print job in a format compatible with the print controller 320 (see Figure 2) of the image inspection device 10 and sends the print job to the image inspection device 10 via the communication line 90.

[0027] A print job includes, for example, print data in PDL (Page Description Language) format and job information. The print data includes, for example, print data consisting of pages 1 to n. The job information includes, for example, print settings such as the number of pages, number of copies, type of paper (recording medium), size, basis weight, single-sided / double-sided printing, and inspection settings (on / off). By turning on the inspection setting, the user can instruct the image inspection device 10 to perform image inspection.

[0028] The communication line 90 may include a LAN (Local Area Network) connecting computers and network devices according to a predetermined standard, or a WAN (Wide Area Network) connecting LANs with dedicated lines. The predetermined standard may be, for example, Ethernet (registered trademark) or Wi-Fi (Wireless Fidelity).

[0029] Note that the number of each of the above-mentioned components connected to the communication line 90 is not limited to the example shown in Figure 1.

[0030] <Configuration of the image inspection device 10> As shown in Figure 1, the image inspection device 10 includes a main unit 200 (also called the main unit of the image forming device), a paper feeder 210, a purge and discharge device 220, a post-processing device 230, an image reading unit 340, an image inspection unit 350, an operation display unit 360, etc. Also, as shown in Figure 2, the image inspection device 10 includes a control unit 310, a print controller 320, an image forming unit 330, a reference image generation unit 380, and a storage unit 391. The image inspection device 10 functions as an image forming device. The image inspection device 10 forms an image on paper fed and transported from the paper feeder 210, etc., using the image forming unit 330 of the main unit 200. The image formed on the paper is read by the scanner 341 of the downstream image reading unit 340, and inspection is performed.

[0031] <Configuration of the paper feeder 210> The paper feeder 210 is equipped with at least one large-capacity paper tray and supplies paper one sheet at a time to the downstream main unit 200 (image forming unit 330).

[0032] <Purge paper output device 220> The purge paper discharge device 220 is provided with a branching section in the transport path, and is equipped with a main transport path leading to the post-processing device 230 and a sub-transport path leading to the purge tray (located above the purge paper discharge device 220 in Figure 1). Paper that has been determined to be of poor quality by the image inspection unit 350 (waste paper) is discharged to the purge tray.

[0033] <Post-processing device 230> The post-processing device 230 performs post-processing on or discharges paper sent from the upstream device according to the settings of the print job. The post-processing device 230 comprises a paper output tray, a post-processing unit, and a transport path. The post-processing device 230 also comprises a control unit, a storage unit, a transport unit, and a communication unit (none of which are shown), which are interconnected via signal lines such as buses for exchanging signals. The post-processing unit of the post-processing device 230 performs at least one post-processing operation on the image-formed paper, such as stapling, punching, cutting, folding, and binding.

[0034] <Configuration of the control unit 310> Refer to Figure 2. The control unit 310 includes an image control unit 311, a DRAM (Dynamic Random Access Memory) control IC 312, a memory 313, an image memory (DRAM) 314, a compression / decompression IC 315, a read processing unit 316, a write processing unit 317, a storage unit 318, etc. The image control unit 311 is composed of a CPU (Central Processing Unit), etc.

[0035] The image control unit 311 loads various programs stored in the storage unit 318 into the memory 313 and, in cooperation with the loaded programs, comprehensively controls the operation of the entire main unit 200.

[0036] The reading processing unit 316 performs various processes such as analog processing, A / D conversion processing, and shading processing on the analog image signal output from the scanner 341 of the image reading unit 340 to generate digital image (read image) data. The generated digital image data is then output to the compression / decompression IC 315 by the DRAM control IC 312. Based on the control of the DRAM control IC 312, the compression / decompression IC 315 performs compression processing on the digital image data and decompression processing on the digital image data after compression processing. The DRAM control IC 312 also controls the input / output of the image memory 314 for the compressed / decompressed digital image data.

[0037] The image memory 314 is composed of DRAM and includes compressed memory and page memory areas internally, for temporarily storing compressed image data, decompressed image data, etc.

[0038] The writing processing unit 317 outputs the decompressed digital image data to the exposure unit 332 of the image forming unit 330.

[0039] <Configuration of Print Controller 320> The print controller 320 analyzes the print job received from the terminal device 40 via the communication line 90, performs processing such as color conversion, screening, and rasterization, and generates a bitmap-format original image. The generated original image is transmitted to the control unit 310. The print controller 320 functions as an original image acquisition unit.

[0040] The print controller 320 comprises a controller control unit 321, a reference image generation control unit 322, a DRAM control IC 323, an image memory (DRAM) 324, a communication control unit 325, a communication interface 326, and the like. The controller control unit 321 comprehensively controls the operation of each part of the print controller 320. The controller control unit 321 also receives print jobs from terminal devices 40, etc., via the communication interface 326. The communication control unit 325 controls the communication interface 326. The communication interface 326 is an interface that transmits and receives data via wired or wireless communication with various terminal devices via the communication line 90.

[0041] The print controller 320 comprises a controller control unit 321, a reference image generation control unit 322, a DRAM control IC 323, an image memory 324, a communication control unit 325, a communication interface 326, and the like. The controller control unit 321 comprehensively controls the operation of each part of the print controller 320. The controller control unit 321 also receives print jobs from terminal devices 40, etc., via the communication interface 326. The communication control unit 325 controls the communication interface 326.

[0042] A received print job includes print data (mainly in PDL format) that forms the basis of the original image, and job information that describes print settings such as the type of paper to be used. The print controller 320 performs rasterization (RIP) processing to convert the print data into page-level bitmap data based on the print settings. The RIP image after rasterization is temporarily stored in the image memory 324. The RIP image in the image memory 324 is temporarily stored in the compressed memory area of ​​the image memory 314 via the compression / decompression IC 315, under the control of the DRAM control IC 323 of the print controller 320 and the DRAM control IC 312 of the control unit 310. During normal printing, the RIP image stored in the compressed memory area is decompressed by the compression / decompression IC 315 and sent to the image forming unit 330 as the original image (image data) via the writing processing unit 317, where printing is performed.

[0043] The reference image generation control unit 322 outputs a reference image generation instruction to the reference image generation unit 380 (described later) to generate a reference image based on the original image at a predetermined generation timing. The predetermined generation timing may be, for example, when the inspection setting described in the job settings of the print job is turned on and the original image acquisition unit has acquired the original image. The reference image generation unit 380 generates a reference image based on the reference image generation instruction.

[0044] <Configuration of the reference image generation unit 380> The reference image generation unit 380 generates a reference image based on the original image acquired by the original image acquisition unit and outputs it to the control unit 310. The reference image generation unit 380 can be realized by a separate CPU (not shown) executing an image inspection program, separate from the image control unit 311.

[0045] Ideally, the scanned image generated by reading the inspection image formed on the paper should match the original image in terms of content. However, when scanning the inspection image formed on the paper, errors can occur in the scanned image compared to the original image due to various factors such as variations in the paper transport path, deviations in the scanner's reading position, color reproduction accuracy, and differences in paper type. Errors can also occur depending on the scanner's resolution. Therefore, simply comparing the scanned image with the original image is likely to result in errors, and it is not practical to inspect the inspection image by simply comparing the scanned image with the original image.

[0046] Therefore, in this embodiment, the reference image generation unit 380 is configured to generate a reference image by performing various processes on the original image regarding position, resolution, color, etc., so that it can be compared with the scanned image, and then compare the reference image with the scanned image. As a result, the comparison with the scanned image is performed appropriately, so that the inspection of printed materials can be performed with high accuracy. Details of the reference image generation process will be described later. In Figure 2, an example is shown in which the reference image generation control unit 322 is provided on the print controller 320, but the reference image generation control unit 322 may also be configured to be provided on the control unit 310.

[0047] <Configuration of the image forming unit 330> The image forming unit 330 forms (prints) an image on paper using an electrophotographic method that includes the steps of charging, exposure, development, transfer, and fixing, according to the instructions of the control unit 310. In this embodiment, the image forming unit 330 forms an inspection image on the paper according to the image forming conditions set based on the print settings, which is to be inspected by the image inspection unit 350. The image forming unit 330 includes a printer control unit 331 and an exposure unit 332, etc. The printer control unit 331 is connected to the image control unit 311 by serial communication and receives control from the image control unit 311. The printer control unit 331 drives the LD (Laser Diode) of the exposure unit 332 by a signal from the writing processing unit 317 to form an electrostatic latent image corresponding to the original image on the photoreceptor (not shown). The toner image formed on the photoreceptor is developed through the development process and transferred onto the paper supplied from the paper feeder 210. The unfixed toner image on the paper is then fixed by heating and pressurizing. The paper on which the toner image has been fixed is transported to the image reading unit 340.

[0048] <Configuration of the image reading unit 340> The image reading unit 340 includes a scanner 341 and a scanner control unit 342. The scanner 341 reads the paper (printed material) being transported along the transport path using an image sensor, such as a CMOS (Complementary Metal-Oxide-Semiconductor) or CCD (Charge Coupled Device). The scanner control unit 342 controls the scanner to read the inspection image formed on the paper transported from the image forming unit 330, according to the reading instruction from the control unit 310. The scanner control unit 342 outputs the read image, which is the inspection image formed on the paper, to the control unit 310.

[0049] <Configuration of the Image Inspection Unit 350> The image inspection unit 350 performs image inspection based on a reference image. More specifically, the image inspection unit 350 acquires a read image obtained by reading the reference image and the inspection image formed on the paper, and inspects the inspection image formed on the paper by comparing the reference image and the read image page by page.

[0050] The image inspection unit 350 includes an image inspection control unit 351. The image inspection control unit 351 includes an image control unit 311, or a CPU, RAM, ROM, and auxiliary storage device (not shown). The function of image inspection on the inspection image is realized by the CPU executing an image inspection program. The control unit 310 determines that the printed material is defective (waste paper) if there is a difference area in the inspection image where the inspection result is defective (abnormal). If there is no difference area of ​​defects in the inspection image, the control unit 310 determines that the printed material is good. Details of the image inspection will be described later.

[0051] <Configuration of the operation display unit 360> The operation display unit 360 includes a touch panel display 361, an operation control unit 362, and hard keys such as a numeric keypad, start button, stop button, etc. The touch panel display includes, for example, a touch sensor and an LCD (Liquid Crystal Display) located behind the touch sensor. The operation control unit 362 receives input from the touch sensor and hard keys and transmits the input data to the control unit 310. The operation control unit 362 also receives output data from the control unit 310 and displays it on the LCD. The operation display unit 360 is used for inputting various settings by the user (e.g., turning inspection settings on / off, setting inspection levels) and instructions (e.g., instructions to start printing). The operation display unit 360 is also used for outputting (displaying) the status of the image inspection device 10, the inspection results of printed materials (good / defective), images of defective printed materials, etc.

[0052] <Configuration of memory unit 391> The reference image generation unit 380 is as described above. The storage unit 391 consists of an auxiliary storage unit such as a hard disk that stores various programs and data in advance. The storage unit 391 stores the reference image generated by the reference image generation unit 380.

[0053] <Functions of control units 310 and 351> Referring to the functional block diagrams showing the functions of the control unit 310 and image inspection control unit 351 in Figure 3, the functions of the control units 310 and 351 will be explained.

[0054] As shown in Figure 3, the control unit 310 functions as a job acquisition unit 319. The job acquisition unit 319 acquires the original image from the print controller 320. It also receives image inspection instructions and image formation condition information from the print controller 320.

[0055] The image inspection control unit 351 functions as a difference image generation unit 510, a level determination unit 511, an inspection level setting unit 512, a pass / fail determination unit 513, and a report generation unit 514.

[0056] The difference image generation unit 510 generates a difference image by comparing a reference image generated by the reference image generation unit 380 for each page with a read image obtained by reading the inspection image on the paper to be inspected. Specifically, it calculates the difference (error) in pixel values ​​for each corresponding pixel in both images and obtains a difference image (image data on a page basis). The difference image generation unit 510 also identifies one or more difference regions from the difference image. Specifically, the difference image generation unit 510 uses clustering to group pixels in the difference image that have a pixel value (difference pixel value) of a predetermined value or greater as connected or continuous units. The difference image generation unit 510 then extracts units in which the number of pixels included in the group is a predetermined number or greater (corresponding to the number x 6 described later) as difference regions.

[0057] The level determination unit 511 classifies the identified difference regions into levels based on the type of anomaly being targeted and a level threshold set in advance according to that type. The level threshold describes various elements such as area (size, number of pixels), diameter, circularity, length, and difference density, according to the type of anomaly being targeted. For example, types of anomalies (defects) include dot-shaped stains (stains), vertical or horizontal line-shaped anomalies (streaks), and defects where the image is white in a circular area (the density becomes lighter) (fireflies). Figure 4A shows an example of a level threshold. This level threshold is stored in the storage unit 390. Here, the storage unit 390 corresponds to either the storage unit 391 or the storage unit 318. For example, if the type of anomaly is stains, it is classified into levels 1 to 6 according to its size. In Figure 4A, the diameter (average number of pixels of the major and minor axes) is used as the indicator for size, but the area (number of constituent pixels) may also be used as the indicator. For example, if the type is dirt, the difference region (group / cluster) to be judged as dirt is classified as Level 1 if the number of pixels in it is x1 or greater. If it is less than x1 but x2 or greater, it is classified as Level 2. The same process is used for Levels 3 through 6. Here, x1 > x2 > x3 > x4 > x5 > x6. Here, the number x6 is the smallest diameter (or number of pixels) that can be identified as a difference region.

[0058] Note that the level thresholds shown in Figure 4A are merely examples, and the types of abnormalities may include types other than dirt, streaks, and fireflies, and some types of abnormalities may be omitted. Also, multiple types of elements may be used for judgment. For example, for dirt, the judgment may be made not only by the size element, but also by a combination of size and density difference. The density difference here refers to, for example, the difference between the average density value of the surrounding pixels and the average density value of the pixels included in the difference region (group / cluster) that is the target of dirt judgment. In addition, the example shown in Figure 4 shows an example where the judgment level is divided into 6 stages from 1 to 6, but there may be fewer or more stages. Furthermore, different numbers of stages may be set for each type of abnormality (similarly for the inspection level).

[0059] The inspection level setting unit 512 specifies the inspection level for the inspection report. The inspection level setting is a threshold for the judgment level at which an item is classified as abnormal. In the example judgment level shown in Figure 4A, the inspection level is set to a range of 1 to 6. The inspection level setting is stored in the storage unit 390 and can be changed or updated by the user.

[0060] The pass / fail determination unit 513 determines pass or fail for each difference region by comparing the determination level determined by the level determination unit 511 with the inspection level set by the inspection level setting unit 512. Figure 4B is a table showing the correspondence between abnormal / normal at the determination level and the inspection level. As shown in Figure 4B, for example, if the inspection level is set to "1", the difference region at determination level 1 is determined to be abnormal (defective). Also, if the inspection level is set to "5", the difference regions from determination levels 1 to 5 are determined to be abnormal.

[0061] The report generation unit 514 generates an inspection report from the inspection results from the pass / fail determination unit 513 and the read image. The generated inspection report is stored in the storage unit 390 along with the difference area list. The difference area list is assigned a level determined by the level determination unit 511 (see Figure 8 below).

[0062] (Configuration of terminal device 40) Figure 5 is a block diagram showing the hardware configuration of the terminal device 40. The terminal device 40 comprises a control unit 410, a storage unit 420, an operation display unit 430, and a communication interface 440. Each component is interconnected by a bus or the like.

[0063] The control unit 410 consists of a CPU, RAM, ROM, etc., and performs control and calculation processing of the terminal device 40, etc., according to the program. The storage unit 420 consists of an auxiliary storage unit such as a hard disk that stores various programs and various data in advance. The operation display unit 430 includes a display unit such as a display and an input unit such as a keyboard, mouse, numeric keypad. The communication I / F 440 is an interface that transmits and receives data via wired or wireless communication with various terminal devices via the communication line 90.

[0064] The terminal device 40 can display an inspection report on the display of the operation display unit 430, showing the inspection results of the printed materials (good / defective), images of defective printed materials, etc.

[0065] (Image inspection device of another embodiment) Figure 6 is a functional block diagram showing how the terminal device 40b according to another embodiment functions as an image inspection device. In the other embodiment, the terminal device 40b performs some of the functions of the image inspection device 10 in the first embodiment shown in Figures 1 to 4B, and the terminal device 40b functions as an image inspection device.

[0066] In the modified example shown in Figure 6, the control unit 410 of the terminal device 40b corresponds to the image inspection control unit 351. The control unit 410 functions as a difference image generation unit 510, a level determination unit 511, an inspection level setting unit 512, a pass / fail determination unit 513, and a report generation unit 514. The storage unit 420 stores the inspection report, difference area list, level threshold, and inspection level setting. These are as described in the first embodiment.

[0067] The difference image generation unit 510 acquires the reference image generated by the reference image generation unit 380 of the image inspection device 10 and the read image generated by the reading unit 340, and generates a difference image by comparing them. Then, the difference region is identified from the difference image, and the level determination unit 511 refers to the determination level threshold and classifies each difference region into levels. The inspection level setting unit 512 sets the inspection level based on the user's specification. The pass / fail determination unit 513 determines the pass / fail status of each difference region by comparing the determination level of each difference region with the inspection level and generates an inspection result. The report generation unit 514 generates an inspection report from the inspection result by the pass / fail determination unit 513 and the read image. The generated inspection report is stored in the storage unit 420 along with the difference region list. In this way, a terminal device 40 connected to the image inspection device 10 via a network may also function as an inspection device.

[0068] (Image examination method) The image inspection method will be described with reference to Figures 7A to 14B. In the following description, the image inspection method will be described as being executed by a program running on the image inspection device 10 according to the first embodiment. Figure 7A is a flowchart of the image inspection process. Figure 7B is a flowchart of the process that follows Figure 7A.

[0069] (Step S11) When a print job is started, the image inspection device 10 acquires the original image from the print controller 320 via the job acquisition unit 319 and stores it in the page memory 1.

[0070] (Step S12) The reference image generation unit 380 generates a reference image from the original image stored in the page memory 1 and stores it in the page memory 1.

[0071] (Step S13) The control unit 310 instructs the image forming unit 330 to output an image. Upon receiving this instruction, the image forming unit 330 forms an image on the paper based on the original image. After the image formation is complete and the paper has been ejected to the downstream device, the main unit 200 notifies the control unit 310 that the ejection is complete.

[0072] (Step S14) The control unit 310 instructs the image reading unit 340 to read the image. The image reading unit 340 reads the inspection image of the object to be inspected on the printed paper that has been transported, and stores the read image obtained from the reading in the page memory 2. The image reading unit 340 also notifies the control unit 310 that the reading is complete.

[0073] (Step S15) The control unit 310 instructs the image inspection unit 350 to perform an image inspection. The image inspection unit 350 performs an image inspection based on the reference image stored in page memory 1 and the read image obtained by reading the inspection image on the paper stored in page memory 2, through the following steps S151 to S154.

[0074] (Step S151) The difference image generation unit 510 generates a difference image by comparing the reference image and the read image. The difference image generation unit 510 also identifies difference regions from the difference image. As described above, the difference region is a group of extracted difference pixels and is a region that is a candidate for a defect (anomaly is not yet determined).

[0075] (Step S152) The level determination unit 511 refers to the level threshold used for determination as shown in Figure 4A and performs level determination (level classification) for each difference region. Figure 8 is an example of a difference region list obtained through the processing described above.

[0076] As shown in Figure 8, the difference region list displays a list of difference regions identified for each page. Each difference region is automatically assigned a unique region ID, and contains difference region information and the judgment level determined by the level determination unit 511. The difference region information includes information such as the type of anomaly classified, its location (x and y coordinates), size, and difference concentration. Note that Figure 8 is merely an example, and the difference region information in the difference region list may omit some of the information, or other information may be included.

[0077] (Step S153) The inspection level setting unit 512 acquires the currently set inspection level (hereinafter referred to as the "first inspection level"). The inspection level setting is stored in the storage unit 390.

[0078] (Step S154) The pass / fail determination unit 513 performs a pass / fail determination by comparing the determination level assigned to each difference region with the first inspection level. Figure 9 is an example of a stain inspection level chart that is referenced when the user sets the inspection level. This chart may be distributed to the user as a printed document, or it may be displayed on the operation display unit 360. If the inspection level was set to level 5 (L5) as the initial value or the previous setting, it is set to detect stains larger than L5 (bad) in the chart shown in Figure 9 (see Figure 4B). In other words, the L5 stain shown in Figure 9 is set as the lowest level at which an abnormality (defect) is detected. The size of the stains at each level in the chart shown in Figure 9 corresponds to the size of the determination levels shown in Figure 4A. For example, the size (diameter) of the L1 stain in Figure 9 corresponds to the x1 pixel in Figure 4A.

[0079] Figure 10A is an example of a difference region list describing the inspection results performed at inspection level 5. The pass / fail determination unit 513 determines that a difference region where the judgment level > inspection level is good, i.e., "normal". It then determines that a difference region where the judgment level ≤ inspection level is bad, i.e., "abnormal".

[0080] (Step S16) The image inspection control unit 351 stores the inspection results, i.e., the difference area list to which abnormal / normal judgment results are assigned, in the storage unit 390, and also notifies the control unit 310 of the inspection results.

[0081] (Step S17) The control unit 310 proceeds to the next step S18 (indicated by the circled number 10) if printing of all pages of the print job has been completed (YES).

[0082] (Steps S18, S19) The control unit 310 instructs the report generation unit 514 to generate an inspection report. In response to the instruction, the report generation unit 514 generates an inspection report that includes the read image and the inspection results.

[0083] Furthermore, the control unit 310 associates the differential area list with the inspection report and stores it in the storage unit 390. This differential area list includes all identified differential areas regardless of whether the inspection result is abnormal or normal. This differential area list also includes differential areas that have been assigned up to the judgment level (judgment level 6) that can be inspected at the most stringent inspection level (inspection level 6). In other words, this differential area list corresponds to the inspection result of the first inspection level and the inspection result of a second inspection result level that has a different inspection result from the first inspection level.

[0084] (Step S20) The control unit 310 displays the inspection report via the operation display unit 360 (or the operation display unit 430 of the terminal device 40; the same applies hereinafter). Figure 10B is an example of the display screen d11 of the inspection report generated based on the inspection results shown in Figure 10A. As shown in Figure 10B, the display screen d11 shows a bookmark a1 for the entire print job and a scanned image a2 of the fourth page.

[0085] Bookmark a1 hierarchically displays the text of the type (name) of anomaly detected on each page of a single job, with each anomaly being presented as a heading. Bookmark a1 corresponds to the inspection results in Figure 10A. The function of bookmark a1 is to allow easy reference to anomalies on specific pages of a print job. For example, the heading [page4]-[dot noise total 2]-[i005 level 2] in bookmark a1 indicates that two stain anomalies were detected on page 4, one of which is named i005, and the stain detection level is 2. Note that the difference areas i005 and i006, which were determined to be anomalies, are included in the evaluation of the inspection report, but the difference area determined to be normal (e.g., i004) is not included in the evaluation of the inspection report and is not displayed. With such bookmark a1, it is possible to grasp the overall picture of the anomaly detection results and to jump to the page where each anomaly was detected from among multiple pages, making it easy to check the anomalies.

[0086] The scanned image a2 can be converted from PDF to a file format such as JPEG and displayed on the screen. In the image region of scanned image a2 where anomaly detection information is embedded, two stains (difference regions i005, i006 that were determined to be anomalies) and annotation marks a3, a4 (bounding boxes) surrounding them are displayed.

[0087] The marks A3 and A4 allow users to easily check the location and condition of stains.

[0088] (Step S21) The inspection level setting unit 512 proceeds to step S22 if it accepts a change in the inspection level from the user (YES). On the other hand, if the user refers to the inspection report and determines that there is no problem with the inspection level, they do not change the inspection level. In this case, the inspection level setting unit 512 does not accept a change in the inspection level (NO) and terminates the process (end).

[0089] (Step S22) Figure 11 shows an example of a setting screen d12 that accepts changes to the inspection level setting displayed on the operation display unit 360. In the following, we will explain the case where the first inspection level > the second inspection level, that is, the case where the user sets the second inspection level to be less stringent than the first inspection level. The case where the first inspection level is changed to be stricter will be described later (Figure 13 onwards). In the example of setting screen d12, the user changes the inspection level to 3. The inspection level setting unit 512 changes the inspection level to the accepted inspection level 3. The changed inspection level is stored in the storage unit 390. Here, the changed inspection level is the second inspection level. In other words, the inspection level setting unit 512 switches the first inspection level to the second inspection level as specified by the user.

[0090] (Steps S23, S24) The pass / fail determination unit 513 retrieves the differential area list stored in the memory unit 390. Since it is stored as a differential area list, a second determination process (step S152) is unnecessary. The pass / fail determination unit 513 then re-inspects each differential area at the modified second inspection level. The control unit 310 may also store the inspection results at the second inspection level in the memory unit 390 in association with an inspection report.

[0091] Figure 12A is an example of a list of difference regions, describing the inspection results after re-examining each difference region at the second inspection level. The inspection level has been changed to a less stringent one when switching from the first inspection level (5) to the second inspection level (3). Therefore, compared to Figure 10A, the inspection results for i006 and i016 have changed from abnormal to normal. Note that in Figure 12A, the changed areas are shaded for clarity.

[0092] (Step S25) The control unit 310 instructs the report generation unit 514 to regenerate the inspection report in conjunction with the switch from the first inspection level to the second inspection level. In response to the instruction, the report generation unit 514 generates an inspection report including the read image and inspection results.

[0093] (Step S26) The control unit 310 displays the regenerated inspection report on the operation display unit 360. Figure 12B is an example of the display screen d13 of the inspection report generated based on the inspection results shown in Figure 12A. As shown in Figure 12B, the display screen d13 shows the bookmark a1 of the entire print job and the read image a2, which have been updated according to the regenerated inspection report. For example, in the bookmark a1 on the display screen d13, the difference area i006 was determined to be normal and is therefore not listed, and the annotation marks (bounding boxes) are not displayed in the read image a2.

[0094] (An example of a stricter second level of testing) (Steps S22-S24) Next, we will explain the case where the first inspection level is less than the second inspection level, that is, the user sets the second inspection level to be stricter than the first inspection level.

[0095] Figure 13 shows an example of a setting screen d14 that accepts changes to the inspection level setting displayed on the operation display unit 360. In this example of setting screen d14, the user changes the inspection level to 6. The inspection level setting unit 512 changes the setting to the accepted inspection level 6 as the second inspection level. The pass / fail judgment unit 513 retrieves the difference area list stored in the storage unit 390 again and re-inspects with the changed second inspection level.

[0096] Figure 14A is an example of a difference region list describing the inspection results after re-examining each difference region at the second inspection level. The inspection level has been changed to a stricter one as the inspection level shifts from the first inspection level (5) to the second inspection level (6). Therefore, in comparison with Figure 10A, the inspection results for i004 and i015 in Figure 14A have changed from normal to abnormal. For clarity, the changed areas are shaded in Figure 14A.

[0097] (Steps S25-S26) The control unit 310 instructs the report generation unit 514 to regenerate the inspection report in conjunction with the switch from the first inspection level to the second inspection level. In response to the instruction, the report generation unit 514 generates an inspection report including the read image and inspection results. The control unit 310 causes the operation display unit 360 to display the regenerated inspection report. Figure 14B is an example of the display screen d15 of the inspection report generated based on the inspection results shown in Figure 14A. As shown in Figure 14B, the display screen d15 shows the bookmark a1 of the entire print job and the read image a2, which have been updated according to the regenerated inspection report. For example, in bookmark a1, the difference area i004 has been newly determined to be abnormal and has been added to the list. Page 12 has also been added to the list of bookmark a1. In addition, in the read image a2, an annotation mark a5 for the difference area i004 has been newly added. In this case, any abnormalities newly added due to the change to the second inspection level may be displayed in a manner that distinguishes them from the abnormalities that were originally present in the first inspection level (e.g., color coding, underlining, shading). For example, on display screen d15, the newly added abnormalities in bookmark a1 are shaded, and annotation a5 is displayed with a thicker line than the others.

[0098] As described above, the image inspection apparatus according to this embodiment is an image inspection apparatus that generates an inspection report showing the inspection result of performing an inspection based on a set first inspection level to determine whether or not a difference region identified from a difference image based on a comparison between a read image generated by reading a recording medium on which an image has been formed and a reference image is abnormal. Furthermore, the image forming apparatus includes a report generation unit that controls the storage of the inspection result based on the set first inspection level and the inspection result based on a second inspection level, which has a different inspection result from the inspection based on the first inspection level, in association with the inspection report. This makes it possible to easily reflect changes in the user's evaluation in the inspection result without forcing a re-inspection of the inspection result for abnormalities in printed materials. In particular, in this embodiment, all difference regions identified by comparison are stored in association with the judgment level determined by the level judgment unit (difference region list). By reading this and performing an inspection with the switched second inspection level, changes in the user's evaluation can be easily reflected in the inspection result of the inspection report.

[0099] The configuration of the image inspection apparatus 10 described above is intended to illustrate the main components of the above embodiment, and is not limited to the above configuration. Various modifications can be made within the scope of the claims. Furthermore, it does not exclude the configurations of a general image forming apparatus. The scope of the present invention should be interpreted in accordance with the attached claims.

[0100] Furthermore, the means and methods for performing various processing in the image inspection apparatus 10 or terminal device 40 according to the above-described embodiment can be implemented by either a dedicated hardware circuit or a programmed computer. The program may be provided, for example, on a computer-readable recording medium such as a USB memory stick or a DVD (Digital Versatile Disc)-ROM, or it may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred to and stored in a storage unit such as a hard disk. The program may also be provided as a standalone application software, or it may be incorporated into the software of the device as a function of the device.

[0101] While embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are for illustrative purposes only and are not limiting. The scope of the present invention should be interpreted in accordance with the language of the appended claims. [Explanation of Symbols]

[0102] 1000 Printing Systems 10. Image inspection equipment 40 Terminal devices 90 Communication lines 200 Main unit (Image forming apparatus main unit) 210 Paper feeder 220 Purge output device 230 Post-processing equipment 310 Control Unit 320 Print Controllers 330 Image forming unit 340 Image reading unit 341 Scanner 350 Imaging Inspection Department 351 Image Inspection Control Unit 360 Operation display section 380 Reference Image Generation Unit 390, 391, 318 Storage section 510 Difference Image Generation Unit 511 Level determination unit 512 Inspection level setting unit 513 Quality Determination Unit 514 Report Generation Department

Claims

1. An image inspection device that generates an inspection report showing the inspection results of an inspection performed based on a set first inspection level, which determines whether or not a difference region identified from a difference image based on a comparison between a read image generated by reading a recording medium on which an image has been formed and a reference image is abnormal, An image inspection apparatus comprising a report generation unit that controls the storage of the inspection results obtained by the set first inspection level and the inspection results obtained by the second inspection level, which have different inspection results from those obtained by the first inspection level, in association with the inspection report.

2. The image inspection apparatus according to claim 1, further comprising a level determination unit that divides the difference region into multiple determination levels based on a preset level threshold.

3. The image inspection apparatus according to claim 2, wherein the report generation unit stores all difference regions identified by comparison in association with the determination level determined by the level determination unit.

4. It is equipped with an inspection level setting unit for setting the inspection level, The image inspection apparatus according to claim 2, wherein the inspection is performed by comparing the determination level of the difference region classified into levels by the level determination unit with a set inspection level.

5. The image inspection apparatus according to claim 1, further comprising an inspection level setting unit that switches the first inspection level to the second inspection level upon user specification.

6. With the switch to the second inspection level mentioned above, The image inspection apparatus according to claim 5, which newly generates an inspection report showing the inspection result of performing an inspection based on the second inspection level to determine whether or not the difference region is abnormal.

7. An image inspection program executed by an image inspection device, Step (a) is to generate an inspection report showing the inspection results, which is performed based on a set first inspection level to determine whether or not the difference region identified from the difference image, which is generated by reading the recorded medium on which the image is formed, is abnormal, based on a set first inspection level. An image inspection program for causing an image inspection device to perform a process including (b) storing, in association with the inspection report, the inspection results obtained by the first set inspection level and the inspection results obtained by the second inspection level, which differ from the inspection results obtained by the first inspection level.

8. The image inspection program according to claim 7, wherein step (a) includes step (a1) of classifying the difference region into a plurality of judgment levels according to a predetermined criterion.

9. The image inspection program according to claim 8, wherein in step (b), all difference regions identified by comparison are stored in association with the determination level determined in step (a1).

10. The step (c) is to set the inspection level, The image inspection program according to claim 8, which performs the inspection by comparing the determination level of the difference region classified in step (a1) with the inspection level set in step (c).

11. The image inspection program according to claim 7, further comprising step (d) of switching the first inspection level to the second inspection level as specified by the user.

12. In conjunction with the switch to the second inspection level in step (d) above, The image inspection program according to claim 11, wherein in step (a), an inspection report is generated showing the inspection result of performing an inspection based on the second inspection level to determine whether or not the difference region is abnormal.

Images