Image processing apparatus, image inspection system, and program

Abstract

To provide an image processing device, an image inspection system, and a program capable of performing color conversion more speedily than in a case of performing color conversion of a normal color and a special color collectively to another color space.SOLUTION: The image processing device comprises a processor. The processor calculates color data for inspection by converting print data that is data basing an image to print and that includes a normal color being a color to use normally and a special color being a color other than the normal color to color data of another color space in which the number of colors is reduced with respect to each of print data of the normal color and print data of the special color, and thereafter composing them, and the device outputs the calculated color data for inspection.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image processing apparatus, an image inspection system, and a program.

Background Art

[0002] Conventionally, an image inspection apparatus has been used that compares print data serving as the source of an image to be printed with read data obtained by reading the printed image, and inspects the printed image.

[0003] Patent Document 1 describes an image inspection system. This image inspection system includes a client PC that issues a print instruction to a DFE, a print server that analyzes a printer language for original image data for which a print instruction has been given and draws the original image data, a printer that prints a manuscript to be inspected based on RIP image data obtained from the print server, an image reading device that reads image data of the manuscript to be inspected printed by the printer, and RGB data (image inspection means) related to the manuscript to be inspected read by the image reading device and RIP image data output from the print server.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when using a special color that is a color other than a normal color in addition to a normal color that is a commonly used color, the data amount of print data sent to the image inspection apparatus may become excessive. At this time, it is possible to reduce the data amount by converting the print data into color data in another color space. However, when performing color conversion of the normal color and the special color together into another color space, a lot of time is required for the conversion process, leading to a decrease in the inspection speed. An object of the present invention is to provide an image processing apparatus, an image inspection system, and a program that can perform color conversion more quickly than when color conversion is performed on a combined normal color and special color to another color space.

Means for Solving the Problems

[0006] The invention according to claim 1 includes a processor, and the processor converts print data including normal colors, which are data serving as a source of an image to be printed and are normally used colors, and special colors, which are colors other than normal colors, into color data in another color space with a reduced number of colors for each of the print data of the normal colors and the print data of the special colors, and then synthesizes them to calculate inspection color data, and outputs the calculated inspection color data. An image processing apparatus characterized by In the invention according to claim 2, the processor converts the inspection color data into first color data, which is color data in the other color space, for the print data of the normal colors, converts the print data of the special colors into second color data, which is color data in the other color space, and calculates the first color data and the second color data by synthesizing them using a mixing ratio representing the degree of influence of the special color on the image. The image processing apparatus according to claim 1 In the invention according to claim 3, the processor calculates a first contribution rate, which is the degree of influence of the special color on the image, based on the first color data for the mixing ratio, and calculates a second contribution rate, which represents the usage rate of the special color, based on the print data of the special color, and calculates the mixing ratio from the first contribution rate and the second contribution rate. The image processing apparatus according to claim 2 In the invention according to claim 4, the first contribution rate is obtained based on the lightness and chroma of the first color data. The image processing apparatus according to claim 3 In the invention according to claim 5, the mixing ratio is calculated by a product having the first contribution rate and the second contribution rate as elements. The image processing apparatus according to claim 3 The invention according to claim 6 is the image processing apparatus according to claim 2, wherein the processor synthesizes the first color data and the second color data by alpha blending using the mixing ratio. The invention according to claim 7 is the image processing apparatus according to claim 1, wherein the color data for inspection is changed according to the order of printing the normal color and the special color. The invention according to claim 8 is the image processing apparatus according to claim 7, wherein the color data for inspection is changed by converting the print data of the normal color into color data in another color space, and taking into account the degree to which the special color affects the image based on the converted color data. The invention according to claim 9 is an image inspection system comprising a printing device that prints an image on a sheet, a reading device that reads the image printed on the sheet by the printing device, an inspection device that inspects the image read by the reading device, and an information processing device that creates color data for inspection which is data of the image to be inspected by the inspection device, the information processing device comprising a processor, the processor calculating the color data for inspection by converting print data including a normal color which is data serving as a source of an image to be printed and is a color normally used and a special color which is a color other than the normal color into color data in another color space with a reduced number of colors for each of the print data of the normal color and the print data of the special color and then synthesizing them, and outputting the calculated color data for inspection. The invention according to claim 10 is a program for causing a computer to realize a function of calculating color data for inspection by converting print data including a normal color which is data serving as a source of an image to be printed and is a color normally used and a special color which is a color other than the normal color into color data in another color space with a reduced number of colors for each of the print data of the normal color and the print data of the special color and then synthesizing them, and a function of outputting the calculated color data for inspection.

Advantages of the Invention

[0007] According to the invention of claim 1, color conversion can be performed more quickly compared to the case where color conversion is performed collectively for the normal color and the special color to another color space. According to the invention of claim 2, it is possible to generate color data for inspection that more closely matches the color of the image to be actually printed. According to the invention of claim 3, it is possible to reflect the degree of influence of the feature on the image when calculating the mixing ratio. According to the invention of claim 4, it is possible to reflect the degree of influence of the feature on the image in consideration of the relationship between the feature and the lightness and chroma of the first color data. According to the invention of claim 5, the mixing ratio can be calculated more easily. According to the invention of claim 6, it is possible to synthesize the first color data and the second color data in consideration of the degree of influence of these on the image. According to the invention of claim 7, it is possible to generate color data for inspection that more closely matches the color of the image to be actually printed. According to the invention of claim 8, it is possible to more easily reflect the degree of influence of the feature depending on the printing order. According to the invention of claim 9, it is possible to provide an image inspection system with a high inspection speed. According to the invention of claim 10, a computer can realize a function capable of performing color conversion promptly, as compared with the case where color conversion is performed on the normal color and the feature together to another color space.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0010] <Explanation of the Entire Image Inspection System> FIG. 1 is a diagram showing a configuration example of an image inspection system 1 in the present embodiment. As shown in the figure, the image inspection system 1 of the present embodiment includes a printing device 10 that prints an image on a sheet of paper, which is a recording medium, and outputs it as a printed document, a reading device 20 that reads the printed image, an image inspection device 30 that inspects the image, and an information processing device 40 that creates print data and inspection color data.

[0011] The printing device 10 is a device having a printer function that prints an image on a sheet of paper, which is a recording medium, and outputs it as a printed document.

[0012] FIG. 2 is a diagram showing a hardware configuration example of the printing device 10. As shown in the figure, the printing device 10 includes a CPU 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, a storage 14, an operation panel 15, an image forming unit 16, and a communication I / F 17. And these perform the exchange of necessary data via a bus B.

[0013] The CPU 11 realizes each function described later by loading various programs stored in the ROM 13 and the like into the RAM 12 and executing them. The RAM 12 is a memory used as a working memory of the CPU 11 and the like. The ROM 13 is a memory that stores various programs and the like executed by the CPU 11. The storage 14 is a HDD (Hard Disk Drive) or an SSD (Solid State Drive), and stores image information and the like used by the image forming unit 16.

[0014] The operation panel 15 is, for example, a touch panel that displays various information and receives operation inputs from the user. When the operation panel 15 is a touch panel, it includes a display unit such as a liquid crystal panel that displays content (information content) as an image in a predetermined area. Further, when a contact object typified by a human finger or a stylus pen contacts the liquid crystal panel or the like, it has a function of detecting the position where the contact object contacts the liquid crystal panel. In the present embodiment, the touch panel is not particularly limited, and various types such as a resistive film method and a capacitance method can be used.

[0015] The image forming unit 16 is an example of a printing mechanism that forms an image on paper. Here, the image forming unit 16 can use an electrophotographic method that transfers toner attached to a photoreceptor onto paper to form an image, or an inkjet method that ejects ink onto paper to form an image.

[0016] The communication I / F 17 transmits and receives various information to and from other devices.

[0017] The reading device 20 reads an image printed on paper by the printing device 10. The reading device 20 is a so-called in-line sensor, and reads an image printed on the paper being conveyed. FIGS. 3(a) to (b) are diagrams for explaining the reading device 20. Here, FIG. 3(a) is a diagram when the reading device 20 is viewed from the same direction as in FIG. 1. Further, FIG. 3(b) is a diagram when the reading device 20 is viewed from the IIIb direction of FIG. 3(a). As shown in the figure, the reading device 20 includes a light source 21, an optical system 22, a CCD (Charge Coupled Device) sensor 23, and a housing 24.

[0018] The light source 21 irradiates light onto the sheet P on which an image is formed. The light source 21 is composed of, for example, a pair of tungsten lamps 21a and 21b. Then, it irradiates light onto the image formed on the sheet P to generate reflected light containing image information.

[0019] The optical system 22 guides the light reflected by the image formed on the sheet P to the CCD sensor 23. In the present embodiment, the optical system 22 is composed of a self-focusing lens array (SLA: registered trademark) which is a lens array. Then, this self-focusing lens array condenses mainly the diffusely reflected light among the reflected light from the image and forms an image on the CCD sensor 23.

[0020] The CCD sensor 23 receives the light guided by the optical system 22. In the CCD sensor 23, CCDs 23a as pixels for receiving the light reflected by the image are arranged in a line. In the present embodiment, CCDs corresponding to each of the colors R (Red), G (Green), and B (Blue) are arranged in three columns, and the image can be measured in each of the RGB colors. That is, the CCD 23a is a three-line color CCD. The CCD 23a is arranged in the main scanning direction for each of the RGB colors. That is, thereby, the image can be read in the main scanning direction. Also, in the sub-scanning direction, since the sheet moves in the sub-scanning direction as the sheet is conveyed, it can be read accordingly. The light received by the CCD 23a is photoelectrically converted into electric charges, and these electric charges are transferred to the read data generation unit 23b.

[0021] The read data generation unit 23b detects the electric charges transferred from the CCD 23a and makes them detection signals. This detection signal becomes the read data obtained by reading the image formed on the sheet. Since the CCD 23a is a three-color CCD of R, G, and B, in the read data generation unit 23b, an R signal, a G signal, and a B signal are generated as read data corresponding to each color.

[0022] The housing 24 is a case for housing the light source 21, the optical system 22, and the CCD sensor 23.

[0023] The image inspection device 30 inspects the image read by the reading device 20. The image inspection device 30 acquires reference image data as color data for inspection from the information processing device 40. Also, the image inspection device 30 acquires inspection image data, which is reading data, from the reading data generation unit 23b of the reading device 20. Then, the reference image data and the inspection image data are compared to inspect the image. This matter will be described in detail later.

[0024] The information processing device 40 creates print data. Further, the information processing device 40 creates color data for inspection, which is data of the image to be inspected by the image inspection device 30. In the present embodiment, the color data for inspection is characterized by being data with the number of colors of the print data reduced. This matter will also be described in detail later.

[0025] The image inspection device 30 and the information processing device 40 are computer devices. Then, the image inspection device 30 and the information processing device 40 perform their respective processes by operating various application softwares under the management of an OS (Operating System). The image inspection device 30 and the information processing device 40 include a CPU (Central Processing Unit) which is an arithmetic means, a main memory which is a storage means, and a storage such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). Here, the CPU executes various programs such as the OS and application softwares. Also, the main memory is a storage area for storing various programs and data used for their execution, and the storage is a storage area for storing input data for various programs and output data from various programs. Further, the image inspection device 30 and the information processing device 40 include a communication interface for communicating with the outside. Here, the CPU is an example of a processor.

[0026] FIG. 4 is a diagram showing the processing flow performed in the image inspection system 1. As shown in the figure, in the image inspection system 1, the information processing device 40 creates print data for printing by the printing device 10. This print data is RIP (Raster Image Processer) data and is color data based on the colors of color materials such as toner used in the printing device 10. In the present embodiment, in addition to C (cyan), M (magenta), Y (yellow), and K (black) as the colors of the color materials, special colors are used. In this case, the four colors of C, M, Y, and K are normal colors that are usually used. On the other hand, the "special color" is a color other than this normal color. The special color is, for example, colors such as red, pink, white, gold, and silver. Also, colorless (clear) may be used as a special color.

[0027] Furthermore, the information processing device 40 creates reference image data as inspection color data for inspecting an image with the image inspection device 30. This reference image data is created based on the print data, as will be described in detail later. And it becomes color data in another color space with the number of colors reduced with respect to the print data. For example, when two special colors are used in addition to the normal colors (four colors), the total number of color data is six colors. The inspection color data of the present embodiment reduces the number of colors from these six colors. For example, the inspection color data is color data consisting of three parameters represented in another color space. The other color space is not particularly limited, but for example, the L * a * b * color space, XYZ color space, L * u * v * color space, HSV color space, RGB color space, etc. can be mentioned. The information processing device 40 performs conversion from six-color data to three-color data. In the present embodiment, the following description will be made assuming conversion to color data in the L * a * b * color space. The conversion method at this time will be described later.

[0028] In the printing device 10, printing is performed on paper based on the print data. Then, the printed paper is conveyed, and the reading device 20 reads the printed image. The reading data read by the reading device 20 is sent to the image inspection device 30 as inspection image data.

[0029] In the image inspection device 30, the data acquisition unit 31 acquires the reference image data created by the information processing device 40 and the inspection image data sent from the reading device 20. Then, for the inspection image data, the edge extraction unit 32 performs edge extraction to extract a part of the image. And the difference between the reference image data and the inspection image data is calculated. Also, the threshold calculation unit 33 calculates a threshold for determining an image defect based on the reference image data. This threshold is for determining that there is no image defect if the difference between the reference image data and the inspection image data is equal to or less than the threshold, and determining that there is an image defect if it exceeds the threshold. Then, the threshold comparison unit 34 compares the difference between the reference image data and the inspection image data with the threshold, and the output unit 35 outputs the image defect extraction result. Thereby, it can be detected whether there is an image defect in the image printed by the printing device 10. Note that this image defect is, for example, a case where dust adheres to the paper, or a case where dots, streaks, etc. that should not originally exist occur in the image.

[0030] <Description of the information processing device 40> Next, the processing performed by the information processing device 40 will be described in detail. FIG. 5 is a block diagram showing the signal processing system in the information processing device 40. The information processing apparatus 40 includes an RGB data acquisition unit 41 that acquires RGB data created for outputting an image by the printing apparatus 10, a PDL generation unit 42 that receives the RGB (Red, Green, Blue) data and converts it into page description language (PDL) code data, a rasterize unit 43 that creates a raster image from the PDL generated by the PDL generation unit 42, a color conversion processing unit 44 that converts the RGB data into CMYK data, a color adjustment unit 45 that performs color adjustment on the CMYK data, a raster image adjustment unit 46 that adjusts the raster image converted by the color adjustment unit 45, a halftone processing unit 47 that performs halftone processing, and a reference image data creation unit 48 that creates reference image data.

[0031] In the present embodiment, first, the RGB data acquisition unit 41 receives RGB data from an external PC. This RGB data is image data that a user using the PC wants to print by the printing apparatus 10. Then, the RGB data is sent to the PDL generation unit 42, and the PDL generation unit 42 converts it into code data described in PDL and outputs it.

[0032] The rasterize unit 43 converts the code data described in PDL output from the PDL generation unit 42 into raster data for each pixel to form a raster image.

[0033] The color conversion processing unit 44 converts the raster data input from the rasterize unit 43 into CMYK data (the colors of the toner, which is a colorant, namely CMYK and spot colors) and spot color data that are the reproducible colors of the printing apparatus 10, and outputs them. This CMYK data consists of C color data, M color data, Y color data, and K color data separated by color. The spot color data consists of color data separated by the colors used as spot colors.

[0034] The tone adjustment unit 45 functions as a tone adjustment means for adjusting the tone of an image formed by the printing apparatus 10. The tone adjustment unit 45 adjusts the tone of this CMYK data and spot color data so as to match the target color that should originally be output by the printing apparatus 10.

[0035] The raster image adjustment unit 46 performs various adjustments on the CMYK data and spot color data output from the tone adjustment unit 45, such as gamma conversion, sharpness processing, and halftone processing, so that better image quality can be obtained by the printing apparatus 10.

[0036] The halftone processing unit 47 performs halftone processing on the print data by dither mask processing using a dither mask having a threshold array determined in advance in the main scanning direction and the sub-scanning direction. As a result, the print data becomes, for example, print data represented by binary values from that represented by multiple values.

[0037] The reference image data creation unit 48 creates reference image data which is color data for inspection. The reference image data creation unit 48 converts the CMYK and spot color data into color data in the L * a * b * color space. That is, in the reference image data creation unit 48, based on the CMYK and spot color data, three color data of L * a * b * are generated.

[0038] <Explanation of the reference image data creation unit 48> Next, a method for creating reference image data as color data for inspection by the reference image data creation unit 48 will be described in detail. FIG. 6 is a flowchart showing the process of creating reference image data by the reference image data creation unit 48. Further, FIG. 7 is a diagram showing the transition of color data when creating color data for inspection by the reference image data creation unit 48.

[0039] First, the reference image data creation unit 48 acquires CMYK and spot color data, which are print data, from the halftone processing unit 47 (step 101). Next, the reference image data creation unit 48 converts the CMYK color data into L * a * b * color data (step 102). Further, the reference image data creation unit 48 converts the spot color data into L * a * b * color data (step 103). This can also be said to be the conversion of the print data of normal colors and the print data of spot colors respectively into the color data of the Lab color space, which is another color space with a reduced number of colors. Hereinafter, the color data of the Lab color space obtained by converting the print data of normal colors is sometimes referred to as the first color data, and the color data of the Lab color space obtained by converting the print data of spot colors is sometimes referred to as the second color data. * a * b * The color data of the Lab color space obtained by converting the print data of normal colors is sometimes referred to as the first color data, and the color data of the Lab color space obtained by converting the print data of spot colors is sometimes referred to as the second color data. * a * b * The color data of the Lab color space obtained by converting the print data of normal colors is sometimes referred to as the first color data, and the color data of the Lab color space obtained by converting the print data of spot colors is sometimes referred to as the second color data. * a * b * color data of the color space is sometimes referred to as the second color data.

[0040] Then, based on the first color data, the reference image data creation unit 48 calculates a first contribution rate BR1, which is the degree to which the characteristic affects the image (step 104). The first contribution rate BR1 is an example of the contribution rate of the characteristic to the image and represents the degree of influence when the characteristic is added to the normal color. That is, if the image formed by the normal color is a high-chroma or dark image, even if the characteristic is added to it, it is considered that the characteristic is hardly reflected in the image. In this case, the contribution rate of the characteristic to the image is small. That is, the effect of adding the characteristic to the normal color is small. On the other hand, if the image formed by the normal color is a low-chroma or bright image, when the characteristic is added to it, it is considered that the characteristic is more greatly reflected in the image. In this case, the contribution rate of the characteristic to the image is large. That is, the effect of adding the characteristic to the normal color is large. Therefore, the first contribution rate BR1 is obtained based on the lightness and chroma of the first color data. Actually, the first contribution rate BR1 is obtained in advance by conducting experiments or the like based on the lightness and chroma of the image.

[0041] Furthermore, based on the printing data of the characteristic, the reference image data creation unit 48 calculates a second contribution rate BR2, which represents the usage rate of the characteristic (step 105). The second contribution rate BR2 is an example of the contribution rate of the characteristic to the image and represents the ratio of the use of the characteristic. That is, when more of the color material of the normal color is used, even if the characteristic is added to it, it is considered that the characteristic is hardly reflected in the image. That is, the effect of adding the characteristic to the normal color is small. On the other hand, when the image formed by the normal color uses little of the color material of the normal color, when the characteristic is added to it, it is considered that the characteristic is more greatly reflected in the image. In this case, the contribution rate of the characteristic to the image is large. That is, the effect of adding the characteristic to the normal color is large. Therefore, it can be said that the second contribution rate BR2 is the coverage (color material coverage rate) of the characteristic. Note that the second contribution rate BR2 is not limited to the case where it is the coverage of the characteristic, and it may be other values according to the coverage of the characteristic. For example, when the coverage of the characteristic is 50%, the second contribution rate BR2 may be set to 0.5 (50%), but it may also be set to 0.7.

[0042] Then, the reference image data creation unit 48 calculates the mixing ratio α from the first contribution rate BR1 and the second contribution rate BR2 (step 106). This mixing ratio α represents the degree of influence of the feature on the image. The mixing ratio α is calculated by the product having the first contribution rate BR1 and the second contribution rate BR2 as elements. In FIG. 7, the mixing ratio α is obtained by simply multiplying the first contribution rate BR1 and the second contribution rate BR2. That is, it is obtained by the following equation (1). However, correction coefficients, weights, etc. may be included as other elements.

[0043] α = BR1 × BR2 …(1)

[0044] Next, the reference image data creation unit 48 calculates the reference image data by synthesizing the first color data and the second color data. Specifically, the reference image data creation unit 48 creates the reference image data by synthesizing the first color data and the second color data using the mixing ratio α (step 107). Here, the reference image data creation unit 48 synthesizes the first color data and the second color data by alpha-blending them using the mixing ratio α. In FIG. 7, the reference image data BlendLab is obtained by the following equation (2). Here, CMYK_Lab is the first color data, and Spot_Lab is the second color data.

[0045] BlendLab = α × Spot_Lab + (1 - α) × CMYK_Lab …(2)

[0046] Then, the reference image data creation unit 48 outputs the calculated reference image data BlendLab to the image inspection apparatus 30.

[0047] <Modification Example> The reference image data BlendLab, which is color data for inspection, may be changed according to the order of printing normal colors and special colors. Depending on the order in which toner is placed on the paper for normal colors and special colors, the degree of influence of the special color on the image is different. Therefore, at least one of the first contribution rate and the second contribution rate is changed according to the order in which toner is placed on the paper for normal colors and special colors. Alternatively, in equation (1), a method of assigning a correction coefficient or weight to at least one of the first contribution rate and the second contribution rate may be used. This can also be said to mean that the reference image data BlendLab is changed by converting the print data of normal colors into color data in another color space and taking into account the degree of influence of the special color on the image based on the converted color data.

Example

[0048] Hereinafter, the processing performed by the reference image data creation unit 48 will be described in more detail using examples. The present invention is not limited to these examples as long as the gist thereof is not exceeded.

[0049] (Example 1) In addition to the toners of each color of CMYK, which are normal colors, white toner was used as a special color. The color data when the coverage of the white toner is 100% is set to (L * a * b * ) = (90, 0, 0). When the coverage of the toners of each color of CMYK is (C, M, Y, K) = (0, 0, 0, 0) and white toner is placed at a coverage of 100% at the location where (L * , a * , b * ) = (95, 0, 0), the first contribution rate BR1 with respect to L * = 95 was set to BR1 = 1.0. Also, the second contribution rate BR2 = 1.0. At this time, the mixing ratio α = 1.0. As a result, as the reference image data BlendLab, L * = 1.0×90 + 0×15 = 90, and a * , b * each become 0. The reference image data BlendLab is (L * , a * , b* ) = (90, 0, 0).

[0050] (Example 2) In addition to the toners of each color of CMYK which are normal colors, a white toner was used as a special feature. The color data when the coverage of the white toner is 100% is, similar to Example 1, (L * a * b * ) = (90, 0, 0). When the coverage of the toners of each color of CMYK is (C, M, Y, K) = (0, 0, 0, 100) and a white toner is placed at a location where (L * , a * , b * ) = (15, 0, 0) with a coverage of 100%, for L * = 15, the first contribution rate BR1 was set to BR1 = 0.3. Also, the second contribution rate BR2 = 1.0. At this time, the mixing rate α = 0.3. As a result, as the reference image data BlendLab, L * = 0.3×90 + 0.7×15 = 37.5, and a * , b * become 0 respectively. Therefore, the reference image data BlendLab is (L * , a * , b * ) = (37.5, 0, 0).

[0051] (Example 3) In addition to the toners of each color of CMYK which are normal colors, a red toner was used as a special feature. The color data when the coverage of the red toner is 100% is set to (L * a * b * ) = (50, 30, 40). When the coverage of the toners of each color of CMYK is (C, M, Y, K) = (0, 0, 50, 0) and a red toner is placed at a location where (L * , a * , b * ) = (85, 0, 60) with a coverage of 100%, (L * , a * , b *) = The first contribution rate BR1 for (85, 0, 60) was set to BR1 = 0.7. Also, the second contribution rate BR2 = 1.0. At this time, the mixing rate α = 0.7. As a result, as the reference image data BlendLab, L * = 0.7×50 + 0.3×85 = 60.5, a * = 0.7×30 + 0.3×0 = 21.0, b * = 0.7×40 + 0.3×60 = 46.0. Therefore, the reference image data BlendLab is (L * , a * , b * ) = (60.5, 21.0, 46.0).

[0052] (Example 4) In addition to the toners of each color of CMYK which are normal colors, a pink toner was used as a special feature. The color data when the coverage of the pink toner is 100% is set to (L * a * b * ) = (70, 70, 0). When the coverage of the toners of each color of CMYK is (C, M, Y, K) = (100, 0, 0, 0) and (L * , a * , b * ) = (60, -30, -50), and the pink toner is placed with a coverage of 70%, the first contribution rate BR1 for (60, -30, -50) was set to BR1 = 0.5. Also, the second contribution rate BR2 = 0.5. At this time, the mixing rate α = 0.25. As a result, as the reference image data BlendLab, L * = 0.25×70 + 0.75×60 = 62.5, a * = 0.25×70 + 0.75×(-30) = -5.0, b * = 0.25×0 + 0.75×(-50) = -37.5. Therefore, the reference image data BlendLab is (L * , a * , b * ) = (62.5, -5.0, -37.5). * , a * , b * ) = (62.5, -5.0, -37.5).

[0053] Conventionally, when printing data with added features to normal colors is sent from the information processing apparatus 40 to the image inspection apparatus 30, the data volume of the printing data increases according to the number of feature colors for the four normal colors of YMCK. For example, when using two feature colors, the printing data to be sent is for six colors, and the data volume of the printing data becomes 1.5 times. That is, since the transfer time of the printing data becomes 1.5 times, it affects the inspection speed and becomes a factor for the inspection speed to slow down. In this embodiment, in the information processing apparatus 40, printing data with added features to normal colors is converted into color data with a reduced number of colors, and this problem is avoided by sending the converted color data to the image inspection apparatus 30. This color data consists of, for example, three parameters. Therefore, the transfer time of the printing data can be reduced. However, for example, when converting six-color printing data using a DLUT (Direct Look Up Table) which is a multidimensional table, the conversion time becomes large, and as a result, it becomes a factor for the inspection speed to slow down. Therefore, in this embodiment, as described above, for each of the normal-color printing data and the feature printing data, they are converted into color data in another color space with a reduced number of colors. In the above description, the CMYK + feature printing data is converted into color data in the L * a * b * color space. Then, after conversion, these color data are synthesized using the mixing ratio α to calculate the reference image data BlendLab. Thereby, the conversion time can be small, and the problem of the inspection speed slowing down can be avoided.

[0054] <Description of the Program> Here, the processing performed by the information processing apparatus 40 in the embodiment described above is realized by the cooperation of software and hardware resources. That is, the CPU inside the control computer provided in the information processing apparatus 40 executes a program for realizing each function of the information processing apparatus 40 to realize these respective functions.

[0055] Therefore, in the present embodiment, the processing performed by the information processing apparatus 40 is to cause a computer to convert print data including data that is the source of an image to be printed and including normal colors that are normally used colors and special colors that are colors other than normal colors into color data in another color space with the number of colors reduced for each of the normal color print data and the special color print data, and then synthesize the converted data to calculate inspection color data, and a function of outputting the calculated inspection color data. It can also be regarded as a program for realizing these functions.

[0056] Note that the program for realizing the present embodiment can be provided not only by communication means but also by storing it in a recording medium such as a CD-ROM and providing it.

[0057] As described above, the present embodiment has been explained, but the technical scope of the present invention is not limited to the scope described in the above embodiment. It is obvious from the description of the claims that various modifications or improvements added to the above embodiment are also included in the technical scope of the present invention.

Explanation of Reference Numerals

[0058] 1... Image inspection system, 10... Printing apparatus, 20... Reading apparatus, 30... Image inspection apparatus, 40... Information processing apparatus, 43... Rasterization unit, 48... Reference image data creation unit

Claims

1. Comprising a processor, The processor, For print data which is data serving as a source of an image to be printed and includes normal colors which are colors for normal use and special colors which are colors other than normal colors, by converting the print data of each of the normal color print data and the special color print data into color data in another color space with the number of colors reduced and then synthesizing them, calculates inspection color data, Outputs the calculated inspection color data, An image processing apparatus characterized by the above.

2. The processor converts the inspection color data, Converts the normal color print data into first color data which is color data in the other color space, Converts the special color print data into second color data which is color data in the other color space, The image processing apparatus according to claim 1, wherein the first color data and the second color data are calculated by synthesizing them using a mixing ratio representing the degree of influence of the special color on the image.

3. The processor determines the mixing ratio, Based on the first color data, calculates a first contribution rate which is the degree of influence of the special color on the image, Based on the special color print data, calculates a second contribution rate representing the usage rate of the special color, The image processing apparatus according to claim 2, wherein the first contribution rate and the second contribution rate are calculated from the above.

4. The first contribution rate is obtained based on the lightness and chroma of the first color data, for the image processing apparatus according to claim 3.

5. The mixing ratio is calculated by a product having the first contribution rate and the second contribution rate as elements, for the image processing apparatus according to claim 3.

6. The processor synthesizes the first color data and the second color data by alpha blending them using the mixing ratio, for the image processing apparatus according to claim 2.

7. The inspection color data is changed according to the order of printing the normal color and the special color, for the image processing apparatus according to claim 1.

8. The inspection color data is changed by converting the normal color print data into color data in the other color space and taking into account the degree of influence of the special color on the image based on the converted color data, for the image processing apparatus according to claim 7.

9. A printing apparatus for printing an image on paper, A reading apparatus for reading the image printed on the paper by the printing apparatus, An inspection apparatus for inspecting the image read by the reading apparatus, An information processing apparatus that creates inspection color data, which is data of an image to be inspected by the inspection apparatus, comprising: The information processing apparatus includes a processor, The processor converts print data, which is data serving as the source of an image to be printed and includes normal colors that are normally used and special colors that are colors other than normal colors, into color data in another color space with a reduced number of colors for each of the print data of the normal colors and the print data of the special colors, and then synthesizes them to calculate inspection color data, outputs the calculated inspection color data, An image inspection system characterized by the above.

10. On a computer, a function of calculating inspection color data by converting print data, which is data serving as the source of an image to be printed and includes normal colors that are normally used and special colors that are colors other than normal colors, into color data in another color space with a reduced number of colors for each of the print data of the normal colors and the print data of the special colors, and then synthesizing them, a function of outputting the calculated inspection color data, A program for realizing the above.

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