JP2015053561A - Printed matter inspection device, printed matter inspection method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed matter inspection device, a printed matter inspection method, and a program capable of improving the accuracy of quality inspection for printed matter.SOLUTION: A printed matter inspection device comprises: a reading section for generating an inspection image by reading printed matter; an acquisition section for acquiring an original image which is the generation source of the printed matter; a multi-value section 213 for making the original image multi-valued; a first smoothing section 215 for performing first smoothing processing on the multi-valued original image; a detection section 217 for performing edge detection on the original image having the first smoothing processing performed, with use of an edge threshold based on the number of print lines of the printed matter; a second smoothing section 219 for performing second smoothing processing on a non-edge area of the multi-valued original image corresponding to an area not detected as an edge in the edge detection; an image processing section 221 for generating a master image by performing image processing on the original image having the second smoothing processing performed; and an inspection section for inspecting the quality of the printed matter by comparing the inspection image with the master image.

Description

  The present invention relates to a printed matter inspection apparatus, a printed matter inspection method, and a program.

  In printing that requires high quality such as production printing, quality inspection for printed matter is required. For example, there is known a printed material inspection apparatus that inspects the quality of a printed material by comparing a master image generated from an original image from which the printed material is generated with an inspection image generated by optically reading the printed material.

  In general, the original image is a low-value image composed of dither patterns, and the inspection image is often a multi-valued image. Often, conversion from a value to a multi-value is necessary.

  However, in the conversion by the smoothing filter, not only the halftone dots but also the edges are smoothed. Therefore, the master image is subjected to non-linear color space conversion and γ correction on the original image after conversion to multivalue by the smoothing filter. Is generated, the edges become thick, and the shapes of the original image and the master image are different. As a result, the shapes of the inspection image and the master image are also different.

  For this reason, for example, Patent Document 1 discloses a technique for detecting an edge from an image and performing smoothing for the edge portion weaker than the non-edge portion.

  However, in the conventional technology as described above, since a uniform threshold is used for edge detection, there is a possibility that the edge cannot be accurately detected depending on the printing condition of the printed matter. For this reason, in the conventional technology as described above, a master image in which the inspection image is accurately reproduced cannot be generated, and there is a possibility that the quality inspection of the printed matter is deteriorated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a printed matter inspection apparatus, a printed matter inspection method, and a program capable of improving the quality inspection accuracy of a printed matter.

  In order to solve the above-described problems and achieve the object, a printed matter inspection apparatus according to one aspect of the present invention acquires a reading unit that reads a printed matter and generates an inspection image, and an original image that is a generation source of the printed matter. An acquisition unit, a multi-value conversion unit that multi-values the original image, a first smoothing unit that applies first smoothing to the multi-valued original image, and the first smoothing. A detection unit that performs edge detection on the original image using an edge threshold value based on the number of printed lines of the printed material, and the multi-valued original image corresponding to an area that is not detected as an edge by the edge detection. A second smoothing unit that performs second smoothing on the non-edge region, an image processing unit that performs image processing on the original image that has been subjected to the second smoothing, and generates a master image; Compare the image with the master image and check the quality of the printed matter. Comprising a checking unit which, a.

  According to the present invention, it is possible to improve the accuracy of quality inspection of printed matter.

FIG. 1 is a schematic diagram illustrating an example of a printed matter inspection system according to the present embodiment. FIG. 2 is a block diagram illustrating an example of a configuration of the printing apparatus and the printed matter inspection apparatus according to the present embodiment. FIG. 3 is a block diagram illustrating an example of a detailed configuration of the master image generation unit of the present embodiment. FIG. 4 is a diagram illustrating an example of the Gaussian filter of the present embodiment. FIG. 5 is a diagram illustrating an example of a Laplacian filter of the present embodiment. FIG. 6 is a flowchart illustrating an example of a flow of a process performed by the printed matter inspection apparatus according to the present embodiment. FIG. 7 is a diagram illustrating an example of a third smoothing Gaussian filter according to the first modification. FIG. 8 is a diagram illustrating an example of the moving average filter of the third modification. FIG. 9 is a diagram illustrating an example of the moving average filter according to the third modification. FIG. 10 is a block diagram illustrating an example of a hardware configuration of the printing apparatus and the printed matter inspection apparatus according to the embodiment and each modification.

  Hereinafter, embodiments of a printed matter inspection apparatus, a printed matter inspection method, and a program according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram illustrating an example of a printed matter inspection system 1 according to the present embodiment. As shown in FIG. 1, the printed matter inspection system 1 includes a printing apparatus 100, a printed matter inspection apparatus 200, and a stacker 300.

  The printing apparatus 100 includes an operation panel 101, photosensitive drums 103Y, 103M, 103C, and 103K, a transfer belt 105, a secondary transfer roller 107, a paper feeding unit 109, a conveyance roller pair 111, and a fixing roller 113. , And an inversion path 115.

  The operation panel 101 is an operation display unit that inputs various operations to the printed material inspection system 1 and displays various screens.

  Each of the photosensitive drums 103Y, 103M, 103C, and 103K forms a toner image by performing an image forming process (charging process, exposure process, developing process, transfer process, and cleaning process), and the formed toner image. Is transferred to the transfer belt 105. In this embodiment, a yellow toner image is formed on the photoreceptor drum 103Y, a magenta toner image is formed on the photoreceptor drum 103M, a cyan toner image is formed on the photoreceptor drum 103C, and the photoreceptor drum 103K is formed. Although a black toner image is formed, the present invention is not limited to this.

  The transfer belt 105 conveys the toner image (full color toner image) transferred from the photosensitive drums 103Y, 103M, 103C, and 103K to the secondary transfer position of the secondary transfer roller 107. In this embodiment, a yellow toner image is first transferred to the transfer belt 105, and then a magenta toner image, a cyan toner image, and a black toner image are sequentially superimposed and transferred. However, the present invention is not limited to this. Is not to be done.

  The paper feeding unit 109 stores a plurality of recording papers, and feeds the recording papers.

  The transport roller pair 111 transports the recording paper fed by the paper feed unit 109 in the direction of arrow s on the transport path a.

  The secondary transfer roller 107 collectively transfers the full-color toner image conveyed by the transfer belt 105 onto the recording paper conveyed by the conveyance roller pair 111 at the secondary transfer position.

  The fixing roller 113 fixes the full color toner image on the recording paper by heating and pressing the recording paper on which the full color toner image is transferred.

  In the case of single-sided printing, the printing apparatus 100 discharges a printed matter, which is a recording sheet on which a full-color toner image is fixed, to the printed matter inspection apparatus 200. On the other hand, in the case of double-sided printing, the printing apparatus 100 sends the recording paper on which the full-color toner image is fixed to the reverse path 115.

  The reverse path 115 reverses the front and back surfaces of the recording paper by switching back the fed recording paper and conveys it in the direction of the arrow t. The recording paper conveyed by the reverse path 115 is re-conveyed by the conveying roller pair 111, the full-color toner image is transferred to the surface opposite to the previous one by the secondary transfer roller 107, fixed by the fixing roller 113, and printed. The paper is discharged to the printed product inspection apparatus 200.

  The printed matter inspection apparatus 200 includes reading units 201A and 201B. The reading unit 201A optically reads one surface of the printed material discharged from the printing apparatus 100, and the reading unit 201B optically reads the other surface of the printed material discharged from the printing device 100. The reading units 201A and 201B can be realized by, for example, a line scanner. Then, the printed matter inspection apparatus 200 discharges the printed matter that has been read to the stacker 300.

  The stacker 300 includes a tray 301. The stacker 300 stacks the printed material discharged by the printed material inspection apparatus 200 on the tray 301.

  FIG. 2 is a block diagram illustrating an example of the configuration of the printing apparatus 100 and the printed matter inspection apparatus 200 according to the present embodiment. As illustrated in FIG. 2, the printing apparatus 100 includes a RIP (Raster Image Processor) unit 121, a print control unit 123, and a printing unit 125. The printed matter inspection apparatus 200 includes a reading unit 201, an acquisition unit 203, a master image generation unit 205, a buffer 207, and an inspection unit 209. In this embodiment, it is assumed that the printing apparatus 100 and the printed material inspection apparatus 200 are connected by a local interface such as USB (Universal Serial Bus) or PCIe (Peripheral Component Interconnect Express). The connection form between the apparatus 100 and the printed matter inspection apparatus 200 is not limited to this.

  The RIP unit 121 receives print data from an external device such as a host device (not shown), and generates an original image (a basis for printing) from which the printed material is generated from the received print data. Specifically, the RIP unit 121 performs RIP processing on the print data and generates a RIP image as an original image.

  In the present embodiment, the print data includes data described in a page description language (PDL) such as PostScript (registered trademark), image data in a TIFF (Tagged Image File Format) format, and the like. However, the present invention is not limited to this. In this embodiment, the original image is CMYK RIP image data, and each pixel of the RIP image data of C (Cyan), M (Magenta), Y (Yellow), and K (Black) is 2 bits at 600 dpi. It shall be, but is not limited to this.

  The print control unit 123 transmits the RIP image generated by the RIP unit 121 to the printed matter inspection apparatus 200 and also to the printing unit 125. Further, the print control unit 123 uses the inspection result transmitted (feedback) from the printed material inspection apparatus 200 to specify, for example, the discharge destination of the printed material that has not passed the quality inspection for the stacker 300 or the quality inspection. The printed material that does not pass is marked, or the printing unit 125 is instructed to perform replacement printing.

  The RIP unit 121 and the printer control unit 123 may be realized by software by causing a processing device such as a CPU (Central Processing Unit) to execute a program, that is, an IC (Integrated Circuit) or an ASIC (Application It may be realized by hardware such as (Specific Integrated Circuit) or may be realized by using software and hardware together.

  The printing unit 125 executes a print processing process such as an image forming process, prints a print image based on the RIP image on a recording sheet, and generates a printed matter. In this embodiment, the printing unit 125 is realized by the photosensitive drums 103Y, 103M, 103C, and 103K, the transfer belt 105, the secondary transfer roller 107, the fixing roller 113, and the like, but is not limited thereto. . As described above, in this embodiment, an image is printed by an electrophotographic method, but the present invention is not limited to this, and an image may be printed by an inkjet method.

  The reading unit 201 reads the printed matter generated by the printing unit 125 and generates an inspection image. Specifically, the reading unit 201 optically reads the print image from the printed material on which the print image based on the RIP image is printed, and generates an inspection image. In the present embodiment, the reading unit 201 is realized by the reading units 201A and 201B. In the present embodiment, the inspection image is RGB image data, and each pixel of the R, G, and B image data has 8 bits of 200 dpi. However, the present invention is not limited to this.

  The acquisition unit 203 acquires the original image that is the generation source of the printed matter generated by the printing unit 125. Specifically, the acquisition unit 203 acquires C, M, Y, and K RIP images from the printing apparatus 100 (print control unit 123).

  The master image generation unit 205 generates a master image based on the original image acquired by the acquisition unit 203. The acquisition unit 203 and the master image generation unit 205 may be realized by causing a processing device such as a CPU to execute a program, that is, by software, or by hardware such as an IC or an ASIC. However, software and hardware may be used in combination.

  FIG. 3 is a block diagram illustrating an example of a detailed configuration of the master image generation unit 205 of the present embodiment. As illustrated in FIG. 3, the master image generation unit 205 includes a multi-value conversion unit 211 and an image processing unit 221.

  The multi-value conversion unit 211 performs multi-value conversion on the original image acquired by the acquisition unit 203. The multi-value conversion unit 211 includes a multi-value conversion unit 213, a first smoothing unit 215, a detection unit 217, and a second smoothing unit 219.

  The multi-value conversion unit 213 multi-values the original image acquired by the acquisition unit 203. In the present embodiment, the multi-value conversion unit 213 multiplies the pixel value of each pixel of each of the C, M, Y, and K RIP images acquired by the acquisition unit 203 by a coefficient and multi-values from 2 bits to 8 bits. Multi-value into value data.

  The first smoothing unit 215 performs first smoothing on the original image multi-valued by the multi-value converting unit 213. Here, the first smoothing by the first smoothing unit 215 prevents not only the edge part (the boundary of the image) but also the halftone part from being detected as an edge in the edge detection by the detection part 217 described later. To be done.

  Specifically, the first smoothing unit 215 generates the first smoothing by the printing unit 125 for each RIP image of C, M, Y, and K in which each pixel is converted to multi-value data of 8 bits. Smoothing is performed using a first smoothing filter having a smoothing coefficient corresponding to the number of printed lines of the printed matter.

  Here, the lower the number of printed lines of the printed material, the rougher the halftone dots of the printed material. Therefore, in order to eliminate the halftone dots of the RIP image, a first smoothing filter having a strong smoothing effect is required. On the other hand, the higher the number of printed lines of the printed matter, the finer the halftone dots of the printed matter. Therefore, the first smoothing filter having a weak smoothing effect is sufficient to eliminate the halftone dots of the RIP image. For this reason, in this embodiment, the 1st smoothing part 215 enlarges the smoothing coefficient of a 1st smoothing filter, and strengthens the smoothing by a 1st smoothing filter, so that the number of printed lines of printed matter is low.

  In the present embodiment, a filtering process using a Gaussian filter represented by Expression (1) is taken as an example of smoothing using the first smoothing filter having a smoothing coefficient corresponding to the number of printed lines of the printed matter. However, the present invention is not limited to this.

  Here, x indicates coordinates in the X direction from the filter center, y indicates coordinates in the Y direction from the filter center, and σ indicates a smoothing coefficient corresponding to the number of printed lines of the printed matter. Note that the smoothing coefficient σ increases as the number of printed lines of the printed material decreases.

  FIG. 4 is a diagram illustrating an example of the Gaussian filter of the present embodiment. The Gaussian filter shown in FIG. 4 is set to σ≈0.8 in Equation (1).

  The detection unit 217 performs edge detection using an edge threshold value based on the number of printed lines of the printed matter generated by the printing unit 125 for the original image subjected to the first smoothing by the first smoothing unit 215. In the present embodiment, the detection unit 217 performs smoothing of the first smoothing filter as an edge threshold value based on the number of printed lines of the printed material for each of the RIP images of C, M, Y, and K subjected to the first smoothing. Edge detection is performed using a threshold value corresponding to the conversion factor.

  Here, the edge of the RIP image becomes weaker as the smoothing by the first smoothing filter (the first smoothing by the first smoothing unit 215) becomes stronger, and the edge of the RIP image becomes weaker as the smoothing by the first smoothing filter becomes weaker. Becomes stronger. Therefore, in this embodiment, the detection unit 217 decreases the edge threshold as the smoothing coefficient of the first smoothing filter increases. For example, the detection unit 217 determines the edge threshold using Equation (2).

  Here, t represents an edge threshold, k represents a coefficient, and a represents a constant. For example, when k = 100, a = −60, and σ = 0.8, t = 65.

  In the present embodiment, a filtering process using a Laplacian filter (secondary differential filter) shown in FIG. 5 is taken as an example of edge detection using an edge threshold corresponding to the smoothing coefficient of the first smoothing filter. Although explained, it is not limited to this.

  Since the Laplacian filter is a second derivative, a positive value and a negative value are obtained across the edge center. However, in this embodiment, a negative value is regarded as zero, and a pixel whose positive value is equal to or greater than the edge threshold is detected as an edge. To do. For example, the detection unit 217 performs edge detection by generating an edge image in which a pixel having a positive value equal to or greater than the edge threshold and a pixel having a positive value less than the edge threshold are binarized.

  The second smoothing unit 219 performs the second smoothing on the non-edge region of the original image multi-valued by the multi-value quantization unit 213 corresponding to the region not detected as an edge by the edge detection by the detection unit 217. Apply.

  Specifically, the second smoothing unit 219 includes C, M, Y, and C generated by the detection unit 217 among C, M, Y, and K RIP images in which each pixel is converted into 8-bit multi-value data. As a second smoothing for the non-edge region corresponding to the region that is not detected as an edge in each of the Y and K edge images, the second smoothing coefficient corresponding to the number of printed lines generated by the printing unit 125 is used. 2 Smoothing is performed using a smoothing filter.

  In the present embodiment, the smoothing coefficient of the first smoothing filter and the smoothing coefficient of the second smoothing filter are the same, but they may be different.

  The image processing unit 211 performs image processing on the original image that has been subjected to the second smoothing by the second smoothing unit 219 (the original image that has been subjected to the multi-value conversion by the multi-value conversion unit 211), and obtains a master image. Is generated. In the present embodiment, the image processing unit 211 includes the resolution conversion unit 223 and the color conversion unit 225, but is not limited to this, and includes a processing unit that performs other image processing. Also good. For example, the image processing unit 211 sets a reference point that serves as a reference for alignment when an inspection unit 209 described below compares an inspection image generated by the reading unit 201 with a master image generated by the image processing unit 211. A processing unit that performs processing may be included.

  The resolution conversion unit 223 converts the resolution of each of the C, M, Y, and K RIP images subjected to the second smoothing by the second smoothing unit 219 from 600 dpi to 200 dpi that is the reading resolution of the reading unit 201. To do. In the present embodiment, the resolution conversion unit 223 converts the resolution by a method in which one pixel is thinned out into three pixels, but the present invention is not limited to this, and any method may be used as the resolution conversion method.

  The color conversion unit 225 converts the C, M, Y, and K RIP images that have undergone resolution conversion by the resolution conversion unit 223 into RGB images. For example, the color conversion unit 225 determines a value of RGB (total 24 bits) of each pixel 8 bits corresponding to CMYK (total 32 bits) of each pixel 8 bits, and converts the CMYK RIP image data into the RGB image data of the determined values. Convert. The color conversion unit 225 performs an interpolation operation using tetrahedral interpolation from eight discrete lattice points in each of C, M, Y, and K to obtain RGB values. Accordingly, the color conversion unit 225 can obtain a set of RGB data for a certain lattice point parameter from a set of CMYK data.

  Returning to FIG. 2, the buffer 207 stores the master image generated by the master image generation unit 205. When an inspection image is generated by the reading unit 201, the buffer 207 outputs a master image used for inspection to the inspection unit 209. The buffer 207 can be realized by, for example, a DRAM (Dynamic Random Access Memory).

  The inspection unit 209 compares the inspection image generated by the reading unit 201 with the master image generated by the master image generation unit 205, and inspects the quality of the printed matter generated by the printing apparatus 100. Specifically, the inspection unit 209 compares the inspection image generated by the reading unit 201 with the master image output from the buffer 207 in units of pixels, and calculates a difference value of pixel values of 8 bits for each RGB color for each pixel. To do. The inspection unit 209 inspects the quality of the printed matter generated by the printing apparatus 100 based on the magnitude relationship between the difference value for each pixel and the threshold value, and transmits (feeds back) the inspection result to the printing apparatus 100. The inspection unit 209, for example, causes a processing device such as a CPU to execute a program, that is, may be realized by software, may be realized by hardware such as an IC or an ASIC, or software and hardware. May be realized in combination.

  FIG. 6 is a flowchart illustrating an example of a flow of processing performed by the printed matter inspection apparatus 200 according to the present embodiment.

  First, the acquisition unit 203 acquires C, M, Y, and K RIP images from the printing apparatus 100 (print control unit 123) (step S101).

  Subsequently, the multi-value conversion unit 213 multiplies the pixel value of each pixel of each of the C, M, Y, and K RIP images acquired by the acquisition unit 203 by a coefficient and multi-value data from 8 bits to 8 bits. Is multi-valued (step S103).

  Subsequently, the first smoothing unit 215 is generated by the printing unit 125 as the first smoothing for each RIP image of C, M, Y, and K in which each pixel is converted into multi-value data of 8 bits. Smoothing is performed using a first smoothing filter having a smoothing coefficient corresponding to the number of printed lines of the printed material (step S105). In the present embodiment, the first smoothing unit 215 increases the smoothing coefficient of the first smoothing filter and strengthens the smoothing by the first smoothing filter as the number of printed lines of the printed material is lower.

  Subsequently, the detection unit 217 uses the smoothing coefficient of the first smoothing filter as an edge threshold value based on the number of printed lines of the printed material for each of the RIP images of C, M, Y, and K subjected to the first smoothing. Edge detection is performed using a threshold value corresponding to (step S107). In the present embodiment, the detection unit 217 decreases the edge threshold as the smoothing coefficient of the first smoothing filter increases.

  Subsequently, the second smoothing unit 219 includes C, M, Y, and C generated by the detection unit 217 among the C, M, Y, and K RIP images in which each pixel is converted into 8-bit multi-value data. The second smoothing of the smoothing coefficient corresponding to the number of printed lines of the printed matter generated by the printing unit 125 is performed as the second smoothing for the non-edge region corresponding to the region that is not detected as the edge in each edge image of K. Smoothing is performed using an activating filter (step S109).

  Subsequently, the resolution conversion unit 223 reads the resolution of the RIP images of C, M, Y, and K that have been subjected to the second smoothing by the second smoothing unit 219 from 600 dpi, and is the reading resolution of the reading unit 201. Conversion to 200 dpi is performed (step S111).

  Subsequently, the color conversion unit 225 converts the C, M, Y, and K RIP images that have undergone resolution conversion by the resolution conversion unit 223 into RGB images (step S113).

  Subsequently, the buffer 207 buffers the master image generated by the master image generation unit 205 (step S115).

  Subsequently, the reading unit 201 optically reads the print image from the printed material on which the print image based on the RIP image is printed, and generates an RGB inspection image (step S117).

  Subsequently, the inspection unit 209 compares the inspection image generated by the reading unit 201 with the master image output from the buffer 207 on a pixel-by-pixel basis, calculates a pixel-value difference value for each RGB 8-bit pixel, Based on the magnitude relationship between the difference value for each pixel and the threshold value, the quality of the printed matter generated by the printing apparatus 100 is inspected (step S119).

  As described above, in this embodiment, since edge detection is performed using an edge threshold value that matches the strength of the first smoothing for edge detection, the edge can be detected accurately, and the inspection image is accurately reproduced. A master image can be generated. For this reason, according to this embodiment, the precision of the quality inspection of printed matter can be improved.

(Modification)
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

(Modification 1)
In the above embodiment, the second smoothing unit 219 performs the second processing on the edge region of the original image multi-valued by the multi-value quantization unit 213 corresponding to the region detected as an edge by the edge detection by the detection unit 217. You may make it further perform the 3rd smoothing weaker than smoothing.

  Specifically, the second smoothing unit 219 includes C, M, Y, and C generated by the detection unit 217 among C, M, Y, and K RIP images in which each pixel is converted into 8-bit multi-value data. A third smoothing filter having a smoothing coefficient smaller than the smoothing coefficient of the second smoothing filter is applied as the third smoothing to the edge area corresponding to the area detected as an edge in each of the Y and K edge images. The smoothing used may be applied.

  FIG. 7 is a diagram illustrating an example of a third smoothing Gaussian filter according to the first modification. The Gaussian filter shown in FIG. 7 is set to σ≈0.5 in Equation (1).

  In this way, it is possible to deal with a case in which an inconvenience arises if some processing is not applied to the edge area of the original image, such as the edge portion of the inspection image being slightly dull due to the scanner characteristics of the reading unit 201. Can do.

(Modification 2)
In the above embodiment, when the first smoothing unit 215 performs smoothing by the first smoothing filter using a uniform smoothing coefficient regardless of the number of printed lines of the printed matter, the detecting unit 217 For each of the smoothed C, M, Y, and K RIP images, edge detection using a threshold corresponding to the number of printed lines may be performed as an edge threshold based on the number of printed lines of the printed matter. .

  In this case, the detection unit 217 detects the halftone dot as an edge more easily as the number of printed lines of the printed material is lower (because the edge of the halftone dot becomes stronger), and detects the edge as the number of printed lines is lower. An edge threshold value that is difficult to set is set, that is, the edge threshold value may be increased as the number of printed lines is lower.

(Modification 3)
In the above embodiment, a moving average filter may be used for the first smoothing of the first smoothing unit 215 and the second smoothing of the second smoothing unit 219. The moving average filter has a smoothing effect that increases as the filter size increases. Therefore, if the number of printed lines is high, a moving average filter having a size of 3 × 3 as shown in FIG. If the number of lines is low, a moving average filter having a size of 5 × 5 as shown in FIG. 9 may be used.

  In this case, since the edge of the RIP image becomes weaker as the size of the moving average filter is larger, the detection unit 217 sets an edge threshold value such that the edge is easier to detect as the size of the moving average filter is larger. The edge threshold value may be reduced as the size of is increased.

(Modification 4)
In the above embodiment, the RIP unit 121, the print control unit 123, and the printing unit 125 that configure the printing apparatus 100 may be configured as separate apparatuses. Moreover, in the said embodiment, you may comprise the printing apparatus 100 and the printed matter inspection apparatus 200 as the same apparatus. In the above embodiment, the printing apparatus 100 and the printed matter inspection apparatus 200 may be connected via a network, and the functions of the printed matter inspection apparatus 200 may be provided in a cloud form.

(Hardware configuration)
FIG. 10 is a block diagram illustrating an example of a hardware configuration of the printing apparatus 100 and the printed matter inspection apparatus 200 according to the embodiment and each modification.

  As shown in FIG. 10, the printing apparatus 100 and the printed matter inspection apparatus 200 have a configuration in which a controller 910 and an engine unit (Engine) 960 are connected by a PCI bus. The controller 910 is a controller that controls the entire control of the printing apparatus 100 or the printed matter inspection apparatus 200, drawing, communication, and input from the operation display unit 920. The engine unit 960 is an engine that can be connected to a PCI bus. In the case of the printing apparatus 100, for example, a printer engine such as a black and white plotter, a one-drum color plotter, or a four-drum color plotter. A scanner engine such as a scanner. The engine unit 960 includes an image processing part such as error diffusion and gamma conversion in addition to the engine part.

  The controller 910 includes a CPU 911, a north bridge (NB) 913, a system memory (MEM-P) 912, a south bridge (SB) 914, a local memory (MEM-C) 917, and an ASIC (Application Specific Integrated Circuit). 916 and a hard disk drive (HDD) 918, and the North Bridge (NB) 913 and the ASIC 916 are connected by an AGP (Accelerated Graphics Port) bus 915. The MEM-P 912 further includes a ROM 912a and a RAM 912b.

  The CPU 911 performs overall control of the printing apparatus 100 or the printed matter inspection apparatus 200, has a chip set including the NB 913, the MEM-P 912, and the SB 914, and is connected to other devices via the chip set.

  The NB 913 is a bridge for connecting the CPU 911 to the MEM-P 912, SB 914, and the AGP bus 915, and includes a memory controller that controls reading and writing to the MEM-P 912, a PCI master, and an AGP target.

  The MEM-P 912 is a system memory used as a memory for storing programs and data, a memory for developing programs and data, a memory for drawing printers, and the like, and includes a ROM 912a and a RAM 912b. The ROM 912a is a read-only memory used as a memory for storing programs and data, and the RAM 912b is a writable and readable memory used as a program / data development memory, a printer drawing memory, and the like.

  The SB 914 is a bridge for connecting the NB 913 to a PCI device and a peripheral device. The SB 914 is connected to the NB 913 via a PCI bus, and a network interface (I / F) unit and the like are also connected to the PCI bus.

  The ASIC 916 is an IC (Integrated Circuit) for image processing having hardware elements for image processing, and has a role of a bridge for connecting the AGP bus 915, the PCI bus, the HDD 918, and the MEM-C 917, respectively. The ASIC 916 includes a PCI target and an AGP master, an arbiter (ARB) that forms the core of the ASIC 916, a memory controller that controls the MEM-C 917, and a plurality of DMACs (Direct Memory) that perform image data rotation by hardware logic and the like. Access Controller) and a PCI unit that performs data transfer between the engine unit 960 via the PCI bus. The ASIC 916 is connected to a USB 940 and an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface (I / F) 950 via a PCI bus. The operation display unit 920 is directly connected to the ASIC 916.

  The MEM-C 917 is a local memory used as a copy image buffer and a code buffer, and the HDD 918 is a storage for storing image data, programs, font data, and forms.

  The AGP bus 915 is a bus interface for a graphics accelerator card proposed for speeding up graphics processing. The AGP bus 915 speeds up the graphics accelerator card by directly accessing the MEM-P 912 with high throughput. It is.

  The programs executed by the printing apparatus 100 and the printed matter inspection apparatus 200 according to the above-described embodiment and each modified example are provided by being incorporated in advance in the ROM 912a or the like.

  The programs executed by the printing apparatus 100 and the printed matter inspection apparatus 200 according to the above-described embodiment and each modified example are files in an installable format or executable format, and are CD-ROM, flexible disk (FD), CD-R, DVD. (Digital Versatile Disk) or the like may be recorded on a computer-readable storage medium and provided.

  Furthermore, the program executed by the printing apparatus 100 and the printed matter inspection apparatus 200 according to the above-described embodiment and each modified example is provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. It may be configured. Further, the program executed by the printing apparatus 100 and the printed matter inspection apparatus 200 according to the above-described embodiment and each modification may be configured to be provided or distributed via a network such as the Internet.

  The program executed by the printing apparatus 100 and the printed matter inspection apparatus 200 according to the above-described embodiment and each modification has a module configuration for realizing the above-described units on a computer. As actual hardware, the CPU 911 reads out a program from the ROM 912a onto the RAM 912b and executes it, whereby the above-described units are realized on a computer.

DESCRIPTION OF SYMBOLS 1 Image inspection apparatus 100 Printing apparatus 101 Operation panel 103Y, 103M, 103C, 103K Photosensitive drum 105 Transfer belt 107 Secondary transfer roller 109 Paper feed part 111 Conveyance roller pair 113 Fixing roller 115 Reverse path 121 RIP part 123 Print control part 125 Printing unit 200 Printed matter inspection apparatus 201, 201A, 201B Reading unit 203 Acquisition unit 205 Master image generation unit 207 Buffer 209 Inspection unit 211 Multi-value conversion unit 213 Multi-value conversion unit 215 First smoothing unit 217 Detection unit 219 Second smoothing Unit 221 image processing unit 223 resolution conversion unit 225 color conversion unit 910 controller 911 CPU
912 System memory 912a ROM
912b RAM
913 North Bridge 914 South Bridge 915 AGP Bus 916 ASIC
917 Local memory 918 Hard disk drive 920 Operation display unit 940 USB
950 IEEE1394 interface 960 engine part

JP 2012-195980 A

Claims (12)

A reading unit that reads a printed matter and generates an inspection image;
An acquisition unit for acquiring an original image from which the printed matter is generated;
A multi-value conversion unit that multi-values the original image;
A first smoothing unit that performs first smoothing on the multi-valued original image;
A detection unit that performs edge detection using an edge threshold value based on the number of printed lines of the printed material on the original image subjected to the first smoothing;
A second smoothing unit that performs second smoothing on a non-edge region of the multi-valued original image corresponding to a region that is not detected as an edge by the edge detection;
An image processing unit that performs image processing on the original image subjected to the second smoothing to generate a master image;
An inspection unit that compares the inspection image with the master image and inspects the quality of the printed matter;
A printed matter inspection apparatus comprising: The first smoothing is smoothing using a first smoothing filter having a smoothing coefficient corresponding to the number of printed lines,
The printed matter inspection apparatus according to claim 1, wherein the edge threshold is a threshold corresponding to the smoothing coefficient.   The printed matter inspection apparatus according to claim 2, wherein the smoothing coefficient increases the smoothing by the first smoothing filter as the value increases.   The printed matter inspection apparatus according to claim 2, wherein the edge threshold value decreases as the smoothing coefficient increases.   The printed matter inspection apparatus according to claim 2, wherein the smoothing coefficient increases as the number of printed lines decreases.   The printed matter inspection apparatus according to claim 2, wherein the second smoothing is smoothing using a second smoothing filter having a smoothing coefficient corresponding to the number of printed lines.   The printed matter inspection apparatus according to claim 6, wherein a smoothing coefficient of the first smoothing filter and a smoothing coefficient of the second smoothing filter are the same.   The second smoothing unit further performs third smoothing weaker than the second smoothing on the edge region of the multi-valued original image corresponding to the region detected as an edge by the edge detection. The printed matter inspection apparatus according to any one of claims 1 to 7.   The printed matter inspection apparatus according to claim 1, wherein the edge threshold is a threshold corresponding to the number of printed lines.   The printed matter inspection apparatus according to claim 9, wherein the edge threshold value increases as the number of printed lines decreases. A reading step of reading a printed matter to generate an inspection image;
An acquisition step of acquiring an original image of a generation source of the printed matter;
A multi-value conversion step of multi-value the original image;
A first smoothing step for applying a first smoothing to the multi-valued original image;
A detection step of performing edge detection using an edge threshold based on the number of printed lines of the printed matter on the original image subjected to the first smoothing;
A second smoothing step for applying a second smoothing to a non-edge region of the multi-valued original image corresponding to a region not detected as an edge by the edge detection;
An image processing step of performing image processing on the original image subjected to the second smoothing to generate a master image;
Comparing the inspection image with the master image and inspecting the quality of the printed matter;
A printed matter inspection method. A reading step of reading a printed matter to generate an inspection image;
An acquisition step of acquiring an original image of a generation source of the printed matter;
A multi-value conversion step of multi-value the original image;
A first smoothing step for applying a first smoothing to the multi-valued original image;
A detection step of performing edge detection using an edge threshold based on the number of printed lines of the printed matter on the original image subjected to the first smoothing;
A second smoothing step for applying a second smoothing to a non-edge region of the multi-valued original image corresponding to a region not detected as an edge by the edge detection;
An image processing step of performing image processing on the original image subjected to the second smoothing to generate a master image;
Comparing the inspection image with the master image and inspecting the quality of the printed matter;
A program that causes a computer to execute.

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