JP2021111117A - Image inspection device and image formation device and program - Google Patents

Abstract

To reliably detect and mask an edge of a content of original image data to prevent misjudgment of abnormalities in the read image data.SOLUTION: An image inspection device comprise: an image acquisition unit that acquires read image data from which an image formed on a recording medium is read and the original image data of the image formation of the read image data; a mask area creation unit that creates a mask area to mask and exclude the area to be detected as abnormal according to the calculated difference value of luminance between pixels of the acquired original image data using a plurality of differential value calculation methods of first and second pixel reference widths; and an analysis unit that performs analysis to detect a normal or abnormal state of the read image data by excluding the created mask areas.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image inspection device, an image forming device and a program.

Conventionally, an image inspection device that reads an image and inspects a streak of the scanned image is known. There is known a technique of detecting a streak-shaped edge by taking a difference (differentiating) between pixels separated by a predetermined pixel in a scanned image and detecting a change in brightness.

Here, with reference to FIGS. 9 and 10, a method of using a derivative (differential filter) as described above will be described as a technique for detecting a streak-shaped edge. FIG. 9A is a diagram showing the differential filter D1. FIG. 9B is a diagram showing an image I1 to which the differential filter D1 is applied. FIG. 10A is a diagram showing the brightness with respect to the coordinates of the image I1. FIG. 10B is a diagram showing the differential value of the luminance with respect to the coordinates of the image I1.

The differential filter detects a small range of differences on the image. For example, as shown in FIG. 9A, consider a differential filter D1 having a pixel reference width of 6 [pixel] for obtaining the pixel value (luminance) of pixels separated by 6 [pixel]. As shown in FIG. 9B, in the image I1, the differential filter D1 is moved and applied to all the pixels. The white part on the image I1 is a streak.

The graph shown in FIG. 10A is a graph in which the horizontal coordinates of the image I1 are taken on the horizontal axis, and the luminance values of one line of pixels in the horizontal direction of the image I1 are taken on the vertical axis. The brightness value is large at the streaks. The graph shown in FIG. 10B is a graph in which the horizontal coordinates of the image I1 are taken on the horizontal axis, and the differential value of the brightness of the pixel using the differential filter D1 in one line of the image I1 is taken on the vertical axis. .. At the edge of the streak, the differential value has a positive maximum value and a negative minimum value.

What is desired to be detected from the scanned image is a streak that occurs as an image abnormality, but the scanned image also has a streak of content. When the edge of the content is detected, it is a false detection because no abnormality has actually occurred. It is desirable not to detect the edges of the content.

Therefore, the limit value of the streak-shaped edge portion (threshold value that can distinguish the edge portion and the non-edge portion) is obtained from the image signal of the inspection target without defects, and the image signal of the inspection target is larger than the limit value. In some cases, a defect inspection device is known that determines a defective product if there is a pixel whose differential value is larger than the reference value by replacing it with a limit value (see Patent Document 1). The edge to be inspected is not detected, only the defect to be inspected is detected.

Further, when the paper on which the image data is printed is read to acquire the scanned image, the edge of the content is detected from the original image (RIP (Raster Image Processer) image) used for printing, and the area of the edge of the content detected there. However, there is a method in which streaks are not detected on the scanned image. That area is called an edge exclusion area as a mask area. The edge detection method from the original image uses the same method as the detection from the scanned image.

In addition, when performing image edge detection by binarizing an image, when calculating the brightness change rate using differentiation, leveling processing is performed to set the brightness of each pixel to the average brightness in a certain range before differentiation2. A binarizing device is known (see Patent Document 2).

Japanese Unexamined Patent Publication No. 6-27037 Japanese Unexamined Patent Publication No. 7-129761

However, in the method using the edge exclusion region, false detection occurs due to the inability to properly detect the edge of the content from the original image in a specific pattern of the image.

The reasons why the edge of the content cannot be detected from the original image are as follows.
(1). Specific frequency pattern in which the differential filter does not respond FIG. 11 is a diagram showing an image I2 to which the differential filter D1 is applied. FIG. 12A is a diagram showing the brightness with respect to the coordinates of the image I2. FIG. 12B is a diagram showing the differential value of the luminance with respect to the coordinates of the image I2.

In a pattern having a specific frequency, the edge may not be detected by the differential filter D1. For example, as shown in FIG. 11, as a pattern having a specific frequency, pixels separated by 6 [pixels] from each other with respect to an image I2 having a pattern in which edges are repeated at a frequency of 6 [pixels] in the horizontal coordinate direction. This is the case to find the difference between.

As shown in FIG. 12 (a), the brightness with respect to the coordinates of one line of the image I2 repeats up and down at a frequency of 6 [pixel] cycles. A differential filter D1 having a pixel reference width of 6 [pixel] is applied to the image I2. Then, as shown in FIG. 12B, the differential value of the luminance with respect to the coordinates of one line in the horizontal coordinate direction of the image I2 is not a value at which the difference in the edge pattern of the image I2 can be detected. As described above, even if the differential filter D1 is applied to the image I2, the difference cannot be detected, so that it cannot be detected as an edge.

The defect inspection device described in Patent Document 1 and the binarization device described in Patent Document 2 do not correspond to the above-mentioned problem (1).

Further, regarding the problem (1) above, the same applies to the scanned image, but the edge of only the scanned image may be detected due to the difference such as noise of the scanned image, and erroneous detection may occur in a place where no abnormality actually occurs. There is. In order to prevent such false detection, it is required to reliably detect the edge existing in the original image and create the edge exclusion area.

An object of the present invention is to reliably detect and mask the edge of the content of the original image data and prevent erroneous determination of an abnormality in the read image data.

In order to solve the above problems, the image inspection apparatus according to claim 1 is
An image acquisition unit that acquires the read image data obtained by reading the image formed on the recording medium and the original image data of the image formation of the read image data.
Using a plurality of difference value calculation methods with different pixel reference widths, the difference value of the brightness between the pixels of the acquired original image data is calculated, and the area for abnormal detection is masked according to the calculated difference value. And the mask area creation part that creates the mask area to exclude
It includes an analysis unit that excludes the created mask area and performs analysis for detecting normality or abnormality of the read image data.

The invention according to claim 2 is the image inspection apparatus according to claim 1.
The difference value calculation method uses a differential filter having a pixel reference width.

The invention according to claim 3 is the image inspection apparatus according to claim 1 or 2.
The plurality of pixel reference widths are not in an integral multiple or an integer fraction.

The invention according to claim 4 is the image inspection apparatus according to any one of claims 1 to 3.
A display control unit that displays the mask area together with the original image data on the display unit is provided.

The invention according to claim 5 is the image inspection apparatus according to any one of claims 1 to 4.
The mask area creation unit determines an area of the original image data using the plurality of difference value calculation methods according to the feature amount of the image of the original image data.

The invention according to claim 6 is the image inspection apparatus according to any one of claims 1 to 5.
The mask area creating unit determines the pixel reference width of the plurality of difference value calculation methods according to the feature amount of the image of the original image data.

The invention according to claim 7 is the image inspection apparatus according to any one of claims 1 to 5.
It is provided with an operation unit that accepts input for setting the pixel reference width of the plurality of difference value calculation methods.
The mask area creation unit determines the pixel reference widths of the plurality of difference value calculation methods according to the plurality of pixel reference widths set and input.

The invention according to claim 8 is the image inspection apparatus according to any one of claims 1 to 7.
The detection of the abnormality is the detection of streaks other than the content.

The image forming apparatus of the invention according to claim 9 is
The image inspection apparatus according to any one of claims 1 to 8.
An image forming unit that forms an image of the original image data on a recording medium,
It includes an image reading unit that reads the image-formed recording medium and generates the read image data.

The program of the invention according to claim 10
Computer,
An image acquisition unit that acquires read image data from which an image formed on a recording medium has been read and original image data for image formation of the read image data.
Using a plurality of difference value calculation methods with different pixel reference widths, the difference value of the brightness between the pixels of the acquired original image data is calculated, and the area for abnormal detection is masked according to the calculated difference value. Mask area creation unit, which creates a mask area to exclude
An analysis unit that excludes the created mask area and performs analysis to detect normality or abnormality of the read image data.
To function as.

According to the present invention, the edge of the content of the original image data can be reliably detected and masked, and an erroneous determination of an abnormality in the read image data can be prevented.

It is a schematic block diagram of the image forming apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the functional structure of an image forming apparatus. It is a flowchart which shows the image inspection process. (A) is a figure which shows the 2nd differential filter. (B) is a diagram showing a second image to which a second differential filter is applied. (A) is a diagram showing the brightness with respect to the coordinates of the second image. (B) is a figure which shows the differential value of the luminance with respect to the coordinates of the 2nd image. It is a figure which shows the luminance with respect to the coordinates of the 2nd image to which the 1st and 2nd differential filters are applied. It is a block diagram which shows the image inspection system of 2nd Embodiment. It is a block diagram which shows the functional structure of an image inspection apparatus. (A) is a figure which shows the 1st differential filter. (B) is a diagram showing a first image to which the first differential filter is applied. (A) is a diagram showing the brightness with respect to the coordinates of the first image. (B) is a figure which shows the differential value of the luminance with respect to the coordinates of the 1st image. It is a figure which shows the 2nd image to which the 1st differential filter is applied. (A) is a diagram showing the brightness with respect to the coordinates of the second image. (B) is a figure which shows the differential value of the luminance with respect to the coordinates of the 2nd image.

The first and second embodiments according to the present invention will be described in detail in order with reference to the accompanying drawings. The present invention is not limited to the illustrated examples.

(First Embodiment)
The first embodiment according to the present invention will be described with reference to FIGS. 1 to 3. First, the apparatus configuration of the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram of the image forming apparatus 100 of the present embodiment. FIG. 2 is a block diagram showing a functional configuration of the image forming apparatus 100.

The image forming apparatus 100 of the present embodiment is an MFP (MultiFunction Peripheral) that forms a color image by an electrophotographic method based on image data obtained by reading an image from a document and image data received from an external device. be.

As shown in FIG. 1, the image forming apparatus 100 includes an operation unit 10, a display unit 20, a document reading unit 30, an image forming unit 40, a paper feeding unit 50, an image reading unit 60, a conveying unit 70, and a paper ejection tray T1,. It is equipped with T2 and the like.

The operation unit 10 has a touch panel formed so as to cover the display screen of the display unit 20, and various operation buttons such as a number button and a start button.

The display unit 20 is composed of an LCD (Liquid Crystal Display), an EL (ElectroLuminescence) display, and the like, and displays various display information on the display screen.

The document scanning unit 30 includes an ADF (Auto Document Feeder), a scanner, and the like, and scans an image of a set document.

The image forming unit 40 forms an image on paper as a recording medium supplied from the paper feeding unit 50. The image forming unit 40 has photoconductor drums 41Y, 41M, 41C, 41K, and charging units 42Y, 42M, 42C, 42K for each of the colors of yellow (Y), magenta (M), cyan (C), and black (K). It has exposure units 43Y, 43M, 43C, 43K, development units 44Y, 44M, 44C, 44K, and primary transfer rollers 45Y, 45M, 45C, 45K. Further, the image forming unit 40 includes an intermediate transfer belt 46, a secondary transfer roller 47, a fixing unit 48, and the like.

A yellow toner image is formed on the photoconductor drum 41Y. The charging unit 42Y uniformly charges the photoconductor drum 41Y. The exposure unit 43Y scans and exposes the surface of the photoconductor drum 41Y with a beam such as a laser beam based on the yellow component of the image data related to the image formation to form an electrostatic latent image. The developing unit 44Y attaches toner to the electrostatic latent image on the photoconductor drum 41Y to develop the image. The primary transfer roller 45Y transfers the toner image formed on the photoconductor drum 41Y onto the intermediate transfer belt 46 (primary transfer). Each part corresponding to magenta, cyan, and black is the same as yellow except that the color (toner) handled is different.

The toner images formed on the photoconductor drums 41Y, 41M, 41C, and 41K are sequentially transferred onto the intermediate transfer belt 46. The secondary transfer roller 47 transfers the toner image formed on the intermediate transfer belt 46 onto the paper (secondary transfer).

The fixing portion 48 includes a fixing belt 48A that heats the paper on which the toner image is transferred, and a pressure roller 48B that pressurizes the paper, and fixes the toner image on the paper by heating and pressurizing.

The paper feed unit 50 includes paper feed trays 51, 52, 53, a paper feed roller, and the like, and supplies paper to the image forming unit 40. Each of the paper feed trays 51 to 53 stores paper of a paper type and size predetermined for each paper feed tray.

The image reading unit 60 is provided downstream of the image forming unit 40 on the paper transport path. The image reading unit 60 reads the surface of a plurality of sheets on which an image is formed, and reads images of R (Red: red), G (Green: green), and B (Blue: blue) corresponding to each of the sheets. Generate data. The image reading unit 60 is a color sensor that receives light emitted from a light source and reflected on the surface of paper by a light receiving element and outputs an RGB signal according to the intensity of the light. The image reading unit 60 is composed of, for example, a line sensor in which a plurality of light receiving elements are arranged at predetermined intervals in the paper width direction orthogonal to the paper transport direction.

The transport unit 70 is composed of a transport roller, a resist roller, and the like for transporting paper, and is arranged on the paper transport path from the paper feed section 50 to the output trays T1 and T2 via the image forming section 40. The paper on the paper transport path is transported. The conveying unit 70 includes an inversion unit that inverts the paper output from the image forming unit 40 and conveys the paper to the image forming unit 40 again, and the image reading unit 60 uses the image forming unit 40 to perform one-sided or double-sided images. The image of the front surface or the front surface and the back surface of the formed paper may be read.

The output trays T1 and T2 are trays on which the image-formed paper discharged from the main body of the image forming apparatus 100 is placed. In the present embodiment, as a result of the image inspection of the paper after the image formation, it is assumed that the paper is ejected to the output tray T1 when it is normal and the paper is ejected to the output tray T2 when it is abnormal. ..

As shown in FIG. 2, the image forming apparatus 100 has an image acquisition unit, a mask area creation unit, a control unit 81 as an analysis unit, an operation unit 10, a storage unit 82, a display unit 20, a communication unit 83, and so on. A document reading unit 30, an image forming unit 40, a paper feeding unit 50, an image reading unit 60, a conveying unit 70, and the like are provided. The control unit 81 functions as an image inspection device.

The control unit 81 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory).
) And the like, and controls each part of the image forming apparatus 100. The control unit 81 reads various programs stored in the storage unit 82, expands them in the RAM, and executes various processes in cooperation with the expanded programs and the CPU.

The operation unit 10 receives a touch input and a button press input from the user, and outputs the operation information to the control unit 81.

The storage unit 82 is composed of a non-volatile storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory, and stores various data and various programs. For example, the storage unit 82 stores an image inspection program for executing an image inspection process described later.

The display unit 20 displays the display information on the display panel according to the display information input from the control unit 81.

The communication unit 83 transmits / receives data to / from an external device such as a PC (Personal Computer) connected via a communication network such as a LAN (Local Area Network). The control unit 81 transmits / receives data to / from an external device via the communication unit 83. For example, the communication unit 83 receives a job including image data for printing from an external device.

The document reading unit 30 reads the set document according to the control of the control unit 81, generates image data thereof, and outputs the image data to the control unit 81.

The image forming unit 40 forms an image on the paper fed from the paper feeding unit 50 according to the control of the control unit 81.

The paper feed unit 50 selects a paper supply source from the paper feed trays 51 to 53 and supplies the paper according to the control of the control unit 81.

The image reading unit 60 reads the image of the paper after image formation output from the image forming unit 40 under the control of the control unit 81, generates the read image data, and outputs the read image data to the control unit 81.

The transport unit 70 supplies the paper stored in the paper feed unit 50 to the image forming unit 40 under the control of the control unit 81, and the image forming apparatus until the paper after image formation is conveyed to the output trays T1 and T2. Paper on the paper transport path is transported within 100.

Next, the operation of the image forming apparatus 100 will be described with reference to FIGS. 3 to 6. FIG. 3 is a flowchart showing an image inspection process. FIG. 4A is a diagram showing the differential filter D2. FIG. 4B is a diagram showing an image I2 to which the differential filter D2 is applied. FIG. 5A is a diagram showing the brightness with respect to the coordinates of the image I2. FIG. 5B is a diagram showing the differential value of the luminance with respect to the coordinates of the image I2. FIG. 6 is a diagram showing the brightness with respect to the coordinates of the image I2 to which the differential filters D1 and D2 are applied.

The external device connected to the image forming apparatus 100 RIP-converts the image data for printing (data in the page description language, bitmap data) into the image data for the image forming apparatus 100 (CMYK bitmap data). A job including CMYK image data for the image forming apparatus 100 is generated and transmitted to the image forming apparatus 100. In the image forming apparatus 100, the control unit 81 receives a job for printing from an external device via the communication unit 83, controls the paper feeding unit 50, the image forming unit 40, the conveying unit 70, and the like, and controls the job. The image data of the above is formed on a paper, and the image reading unit 60 is made to read the image of the paper after the image formation. The image data of the job received from the external device is used as the original image data. Further, the image data generated after the image is read by the image reading unit 60 is used as the image data to be read.

Then, in the image forming apparatus 100, the image reading unit 60 reads the image of the paper after image formation corresponding to a certain original image data (hereinafter, simply referred to as the original image data), and the RGB read image data is generated. With this as a trigger, the control unit 81 executes the image inspection process according to the image inspection program stored in the storage unit 82.

As shown in FIG. 3, the control unit 81 converts the CMYK original image data into RGB original image data (step S1). Step S1 may be executed before the scanned image data is generated.

Then, the control unit 81 converts the resolution of the (RGB) read image data to a predetermined low resolution (step S2). Here, for example, the read image data of 100 [dpi] is converted into the read image data of 50 [dpi]. Therefore, the processing load of the control unit 81 that performs image processing in the subsequent process is reduced.

Then, the control unit 81 differentially filters the read image data after the resolution conversion by using the differential filter (step S3). In step S3, a differential filter having a predetermined pixel reference width (for example, 6 [pixel] as shown in FIG. 9A) in which the pixels for which the difference is taken is separated by a predetermined length is used, and the lateral direction (main scanning direction) is used. While the differential filter is moved for the predetermined line, the differential value of the brightness on the horizontal axis (main scanning direction) of the scanned image data is calculated for all the lines on the vertical axis (horizontal direction, sub-scanning direction). Will be. In this way, the differential value of the brightness of the entire surface of the read image data is calculated.

Further, in parallel with step S2, the control unit 81 executes an edge exclusion area creation process (step S4). In step S4, first, the control unit 81 differentiates the (RGB) original image data by using a differential filter having a predetermined first pixel reference width (for example, 6 [pixel]) in the same manner as in step S3. Filter (step S41). The original image data after the differential filtering becomes the image data of the differential value of the brightness.

Then, the control unit 81 binarizes the original image data after the differential filtering in step S41 by comparing with a predetermined threshold value, and creates the binarized original image data indicating the region with the edge exclusion region. (Step S42). The predetermined threshold value in step S42 is a threshold value for dividing the differential value of the luminance into the edge exclusion region and the other region, and the predetermined threshold value (maximum value-minimum value) of the differential value of the luminance is set in advance. The above area is defined as an edge exclusion area (= 1) indicating the edge area of the content, and the area where the differential value of luminance (maximum value-minimum value) is smaller than a predetermined threshold value is the other area (= 0). Will be done.

Further, in parallel with step S41, the control unit 81 uses a differential filter having a predetermined second pixel reference width different from the first pixel reference width in the same manner as in step S3 to obtain the (RGB) original image. The data is differentially filtered (step S43). In step S43, for example, the differential filter D2 having a second pixel reference width of 4 [pixel] shown in FIG. 4A is used.

Here, as shown in FIG. 4B, consider a case where the differential filter D2 is applied to the image I2 having a pattern of repeating edges at a frequency of 6 [pixel] cycles in the horizontal coordinate direction as the original image data. .. As shown in FIG. 5A, the luminance value in the coordinate direction in one line of the image I2 is repeated up and down at a frequency of 6 [pixel] period. Then, as shown in FIG. 5B, the differential value of the luminance with respect to the coordinates of one line of the image I2 is a maximum value sufficiently large at a frequency of 6 [pixel] period corresponding to the edge pattern of the image I2. It has a small minimum value and is repeated, and it is a value that can detect the difference indicating the edge.

When the first pixel reference width and the second pixel reference width are in a relationship of an integral multiple or a fraction of an integer, there is a possibility that the difference cannot be detected by both differential filters, so an integer. It is set so that the relationship is not double or one-tenth of an integer.

Then, similarly to step S42, the control unit 81 binarizes the original image data after the differential filtering in step S43 by comparison with a predetermined threshold value, and after binarization indicating the region with the edge exclusion region. The original image data is created (step S44).

Then, the control unit 81 takes an OR (logical sum) of the binarized original image data created in step S42 and the binarized original image data created in step S44 and synthesizes them. The original image data (original image data after binarization synthesis) is generated (step S45). As shown in FIG. 6, the original image data after binarization synthesis generated in step S45 has a first pixel reference width of 6 [pixcel] in the image (brightness value with respect to the coordinates) of the original image data. It corresponds to the original image data after binarization when both the differential filter and the differential filter of 4 [pixcel] of the second pixel reference width are applied.

Then, the control unit 81 performs affine transformation or the like on the original image data after the binarization synthesis, and obtains the position of the image of the original image data after the binarization synthesis to be the position of the image of the (RGB) read image data. (Step S46). Then, the control unit 81 converts the resolution of the original image data after the binarization synthesis after the alignment into the same predetermined low resolution as in step S2 (step S47).

Then, the control unit 81 adds the read image data after differential filtering generated in step S3 to the region corresponding to the edge exclusion region of the original image data after the binarization synthesis after resolution conversion generated in step S47. A mask is applied, and the scanned image data other than the masked edge exclusion area is compared with a predetermined threshold value set in advance (step S5). The predetermined threshold value in step S5 is a threshold value for dividing the luminance differential value into streaks and non-streaks, and the region where the luminance differential value (maximum value-minimum value) is equal to or greater than the predetermined threshold value is the streak. It is determined that the region where the differential value of the luminance (maximum value-minimum value) is smaller than a predetermined threshold value is not a streak. In step S5, the comparison is not actually performed for all the pixels of the original image data and the read image after the differential filtering, and for example, the same main scan is performed for each predetermined length line (for example, 10 lines) in the sub-scan direction. The average value of the differential value of the brightness at the position in the direction is calculated, and the average value of the differential value of the brightness is compared with a predetermined threshold value. The predetermined length lines are shifted by a predetermined number of lines (for example, 5 lines), and each time, a comparison with a predetermined threshold value and a streak determination are made.

Then, when the read image data after the differential filtering has a streak (at a position different from the edge of the content), the control unit 81 determines the streak as a streak other than the content, and determines whether or not there is a streak other than the content. Is determined (abnormality analysis) (step S6). For example, if at least one streak other than the content is determined in the read image data by comparison with the predetermined threshold value for each movement of the predetermined length line and determination of the streak, it is determined that there is a streak other than the content. And.

When there is no streak other than the content (step S6; NO), the control unit 81 controls the transport unit 70 to obtain the read image data as the result of inspection of the read image data after the streak determination is normal. The corresponding image-formed paper is ejected from the output tray T1 (step S7), and the image inspection process is completed. When there is a streak other than the content (step S6; YES), the control unit 81 controls the transport unit 70 as a paper discharge in which the inspection result of the read image data after the streak determination is abnormal, and the read image data has a streak. The corresponding image-formed paper is ejected from the output tray T2 (step S8), and the image inspection process is completed.

As described above, according to the present embodiment, the image forming apparatus 100 acquires the read image data in which the image formed on the paper as the recording medium is read and the original image data for image formation of the read image data, and is different. Using the first and second pixel reference width difference value calculation methods, the difference value of the brightness between the pixels of the acquired original image data is calculated, and the area for abnormal detection is masked according to the calculated difference value. A control unit 81 is provided which creates a mask area (edge exclusion area) for exclusion, excludes the created mask area, and performs analysis for detecting normality or abnormality of read image data. The difference value calculation method uses a differential filter having a pixel reference width.

Therefore, the edge of the content of the original image data can be reliably detected and masked as an edge exclusion area, and it is possible to prevent erroneous determination of an abnormality in the read image data.

Further, the first and second pixel reference widths are not in an integer multiple or an integer fraction. Therefore, even if the original image data includes a specific frequency pattern, the edge of the content of the original image data can be detected and masked more reliably, and an erroneous determination of an abnormality in the read image data can be further prevented.

Further, the detection of abnormality is the detection of streaks other than the content. Therefore, it is possible to detect an abnormality caused by a streak other than the content.

Further, the image forming apparatus 100 reads a control unit 81 as an image inspection apparatus, an image forming unit 40 that forms an image of the original image data on a recording medium, and an image reading that reads the image-formed paper and generates the scanned image data. A unit 60 is provided. Therefore, it is possible to reliably detect the edge of the content of the original image data and mask it as an edge exclusion area without preparing and connecting an image inspection device as a separate device, and erroneous determination of an abnormality in image formation by the own device can be performed. Can be prevented.

(Second Embodiment)
A second embodiment according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a block diagram showing the image inspection system 1 of the present embodiment. FIG. 8 is a block diagram showing a functional configuration of the image inspection device 200.

In the first embodiment, the paper after image formation is inspected inside the image forming apparatus 100, and the paper is discharged according to the inspection result. However, in the present embodiment, the image as an external device is used. The inspection device 200 is configured to read and inspect the image-formed paper that has been image-formed and discharged by the image-forming device 100A.

As shown in FIG. 7, the image inspection system 1 of the present embodiment includes an image forming apparatus 100A and an image inspection apparatus 200. The image forming apparatus 100A has substantially the same configuration as the image forming apparatus 100, but does not have an image reading unit 60 and does not have a function of executing an image inspection process. The image forming apparatus 100A and the image inspection apparatus 200 are connected via a communication network N. The communication network N is a network such as a LAN.

The image inspection device 200 is an information processing device that is composed of a PC or the like and that reads and inspects an image of paper on which an image is formed by the image forming device 100A.

As shown in FIG. 8, the image inspection device 200 has an image acquisition unit, a mask area creation unit, an analysis unit, a control unit 201 as a display control unit, an operation unit 202, a storage unit 203, and a display unit 204 as functional configurations. It includes a communication unit 205, an image reading unit 206, and the like.

The control unit 201 is composed of a CPU, RAM, and the like, and controls each unit of the image inspection device 200. The control unit 81 reads various programs stored in the storage unit 82, expands them in the RAM, and executes various processes in cooperation with the expanded programs and the CPU.

The operation unit 202 has a pointing device such as a keyboard and a mouse, receives key input and position input from the user, and outputs the operation information to the control unit 201.

The storage unit 203 is composed of a non-volatile storage device such as an HDD or SSD, and stores various data and various programs. For example, the storage unit 203 stores an image inspection program for executing an image inspection process described later.

The display unit 204 displays the display information on the display panel according to the display information input from the control unit 201.

The communication unit 205 is composed of a network card or the like, and transmits / receives data to / from an external device such as an image forming device 100A connected via the communication network N. The control unit 201 transmits / receives data to / from an external device via the communication unit 205.

The image reading unit 206 is composed of a scanner or the like, and under the control of the control unit 201, the image forming apparatus 100A reads an image of the image-formed and discharged paper after image formation, and generates RGB-read image data thereof. Is output to the control unit 201.

Next, the operation of the image inspection system 1 will be described. First, for example, the control unit 201 of the image inspection device 200 RIP-converts the image data for printing to be inspected into the image data for the image forming apparatus 100A, and includes the image data of CMYK for the image forming apparatus 100A. A job for printing is generated, the job is transmitted to the image forming apparatus 100A via the communication unit 205, and the job is stored in the storage unit 203. The RIP-converted CMYK image data of this stored job is used as the original image data. A job for printing is created and transmitted by another information processing device connected to the communication network N, and the control unit 201 processes the original image data of the job via the communication unit 205 to process the other information processing. It may be configured to receive from the device.

The control unit 81 of the image forming device 100A receives a job for printing from the image inspection device 200 via the communication unit 83, and depending on the job for printing, the paper feeding unit 50, the image forming unit 40, and the transfer. The image data of the job is formed on paper and discharged by controlling the unit 70 and the like. The user sets the discharged image-formed paper in the image reading unit 206 of the image inspection device 200.

Then, in the image inspection device 200, the image reading unit 206 reads the image of the paper after image formation corresponding to the original image data of the job stored in the storage unit 203, and the RGB read image data is generated. The control unit 201 executes the image inspection process according to the image inspection program stored in the storage unit 203.

The image inspection process executed by the control unit 201 is the same as that shown in FIG. 3, but the control unit 201 uses the result information (abnormal analysis result information) of the determination of the presence or absence of streaks other than the content in step S6. It shall be displayed on the display unit 204. At this time, the control unit 201 displays the original image of the original image data, the mask area (edge exclusion area) thereof, and the determination result information of the streaks other than the content on the display unit 204. Further, the control unit 201 may be configured to display the original image of the original image data and its mask area, the read image of the read image data, and the determination result information of the streaks other than the content on the display unit 204.

As described above, according to the present embodiment, the same effect as that of the first embodiment can be obtained. Further, the image inspection device 200 displays the mask area (edge exclusion area) on the display unit 204 together with the original image data. Therefore, the user can easily visually confirm which area in the original image is the exclusion area for abnormality detection.

Further, the image inspection device 200 includes an image reading unit 206 that reads the image-formed paper and generates the read image data. Therefore, even if the image forming apparatus 100A is in an offline state after forming an image, the edge of the content of the original image data can be reliably detected and masked as an edge exclusion region, and an erroneous determination of abnormality can be prevented.

In the above description, an example in which an HDD or the like is used as a computer-readable medium for the program according to the present invention has been disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also applied to the present invention as a medium for providing data of a program according to the present invention via a communication line.

The description in the above embodiment is an example of a suitable image inspection device, image forming device, and program according to the present invention, and is not limited thereto.

For example, in the image inspection process of the first embodiment, along with the normal paper ejection (step S7) and the abnormal paper ejection (step S8), the control unit 81 controls the original image data as in the second embodiment. At least one of the original image, its mask area, the scanned image of the scanned image data, and the determination result information of the streaks other than the content may be displayed on the display unit 20.

Further, in each of the above embodiments, in steps S41 and S43 of the image inspection process, the area of the original image data using the plurality of differential filters having different pixel reference widths is the entire surface, but the region is not limited to this. .. The control unit 81 (control unit 201) may determine a region of the original image data using a plurality of differential filters having different pixel reference widths according to the feature amount of the image of the original image data. For example, looking at the dynamic range as the feature amount of the brightness of the area with the original image data, the area with a small difference in the dynamic range is processed by one type of differential filter with a pixel reference width, and the difference with a large dynamic range. In a region with a large number of images, a configuration may be configured in which processing is performed by a differential filter having a plurality of pixel reference widths. Since the amount of processing of the control unit 81 (control unit 201) increases when a differential filter having a plurality of pixel reference widths is used, it is better not to apply it to an area where the difference is originally small and no edge exists, which saves processing resources. And the processing load can be reduced.

Further, the control unit 81 (control unit 201) may determine the pixel reference width of the differential filter according to the feature amount of the image of the original image data. For example, it is possible to know what kind of frequency pattern exists from the spatial frequency characteristic as the feature amount of the image of the original image data. If a differential filter with a pixel reference width that matches the frequency of the spatial frequency characteristic of the image of the original image data is used, as in the case of applying the differential filter D1 to the image I2 of FIG. 11, the edge may not be detected. Therefore, it is desirable to set the frequency to a pixel reference width that is avoided. With this configuration, it is possible to more reliably detect the edge of the content of the original image data and mask it as an edge exclusion area, and it is possible to further prevent erroneous determination of an abnormality in the read image data.

Further, in each of the above embodiments, in steps S41, S43, and S2 of the image inspection process, the first and second pixel reference widths and predetermined pixel reference widths of the applied differential filter have a preset configuration. There was, but it is not limited to this. The control unit 81 (control unit 201) receives input of a plurality of pixel reference widths from the user via the operation unit 10 before or during the execution of the image inspection process, and responds to the input of the plurality of pixel reference widths. Therefore, the pixel reference widths of the plurality of differential filters to be applied may be determined. The width of the edge (streak) that can be detected changes depending on the pixel reference width. For example, when it is desired to detect a thin streak, setting a narrow pixel reference width makes it easier to detect the streak. By setting the pixel reference width by the user in this way, the edge (streak) of the pixel reference width that the user wants to detect can be detected.

Further, the detailed configuration and detailed operation of each part constituting the image forming apparatus 100 and the image inspection system 1 in the above embodiments can be appropriately changed without departing from the spirit of the present invention.

100 Image forming device 10 Operation unit 20 Display unit 30 Original reading unit 40 Image forming unit 41Y, 41M, 41C, 41K Photoreceptor drum 42Y, 42M, 42C, 42K Charging unit 43Y, 43M, 43C, 43K Exposure unit 44Y, 44M, 44C, 44K Development unit 45Y, 45M, 45C, 45K Primary transfer roller 46 Intermediate transfer belt 47 Secondary transfer roller 48 Fixing unit 48A Fixing belt 48B Pressurizing roller 50 Paper feed unit 51, 52, 53 Paper feed tray 60 Image reading Unit 70 Conveying unit T1, T2 Paper ejection tray 81 Control unit 82 Storage unit 83 Communication unit 1 Image inspection system 100A Image forming device 200 Image inspection device 201 Control unit 202 Operation unit 203 Storage unit 204 Display unit 205 Communication unit 206 Image reading unit N communication network

Claims (10)

An image acquisition unit that acquires the read image data obtained by reading the image formed on the recording medium and the original image data of the image formation of the read image data.
Using a plurality of difference value calculation methods with different pixel reference widths, the difference value of the brightness between the pixels of the acquired original image data is calculated, and the area for abnormal detection is masked according to the calculated difference value. And the mask area creation part that creates the mask area to exclude
An image inspection apparatus including an analysis unit that excludes the created mask area and performs analysis for detecting normality or abnormality of the read image data. The image inspection apparatus according to claim 1, wherein the difference value calculation method uses a differential filter having a pixel reference width. The image inspection apparatus according to claim 1 or 2, wherein the plurality of pixel reference widths are not an integral multiple or an integer fraction. The image inspection apparatus according to any one of claims 1 to 3, further comprising a display control unit that displays the mask area together with the original image data on the display unit. The mask area creating unit is described in any one of claims 1 to 4, wherein the area of the original image data is determined by using the plurality of difference value calculation methods according to the feature amount of the image of the original image data. Image inspection equipment. The image inspection apparatus according to any one of claims 1 to 5, wherein the mask area creating unit determines a pixel reference width of the plurality of difference value calculation methods according to an image feature amount of the original image data. .. It is provided with an operation unit that accepts input for setting the pixel reference width of the plurality of difference value calculation methods.
The image inspection according to any one of claims 1 to 5, wherein the mask area creating unit determines the pixel reference width of the plurality of difference value calculation methods according to the plurality of pixel reference widths set and input. Device. The image inspection apparatus according to any one of claims 1 to 7, wherein the abnormality is detected by detecting streaks other than the content. The image inspection apparatus according to any one of claims 1 to 8.
An image forming unit that forms an image of the original image data on a recording medium,
An image forming apparatus including an image reading unit that reads the image-formed recording medium and generates the read image data. Computer,
An image acquisition unit that acquires read image data from which an image formed on a recording medium has been read and original image data for image formation of the read image data.
Using a plurality of difference value calculation methods with different pixel reference widths, the difference value of the brightness between the pixels of the acquired original image data is calculated, and the area for abnormal detection is masked according to the calculated difference value. Mask area creation unit, which creates a mask area to exclude
An analysis unit that excludes the created mask area and performs analysis to detect normality or abnormality of the read image data.
A program to function as.

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