Image processing-based printing machine color tracking method, device, equipment and storage medium

Abstract

The application discloses a printing machine color tracking method and device based on image processing, equipment and a storage medium, and relates to the technical field of printing. The method prints a preset color chart by a first printing machine and a second printing machine to obtain a first color chart and a second color chart; then, the same image acquisition device is used to acquire the first color chart and the second color chart to obtain a first sampling chart and a second sampling chart; a first lookup table and a second lookup table are obtained according to the preset color chart and the first sampling chart and the second sampling chart; a second image is obtained by processing a first image according to the first lookup table and the second lookup table; then, the first image and the second image are input into the first printing machine and the second printing machine for printing to obtain a printed image with consistent colors. The method is simple and fast, and color matching can be completed without changing the state of the printing machine, thereby saving time and effort and improving color tracking efficiency.

Description

Technical Field

[0001] This invention relates to the field of printing technology, and in particular to a color matching method, apparatus, device, and storage medium for printing presses based on image processing. Background Technology

[0002] In practical production applications, when the output color of one or more secondary printing presses is required to match the output color of the primary printing press, it is necessary to adjust the output color of the secondary printing presses with the primary printing press as the color-tracking target; that is, to perform color-tracking processing on the secondary printing presses. One existing approach involves adjusting the color management profile of the secondary printing press. By adjusting the color management profile, the ink output of each channel of the secondary printing press is controlled, thereby ensuring the output color matches that of the primary printing press. Creating the color management profile requires controlling the printing press to print color patches containing multiple colors, and then using a spectrophotometer to scan each color patch individually to obtain its color information before creating the color management profile. However, simply adjusting the color management profile of the secondary printing press is insufficient to achieve good color-tracking results, and it is time-consuming, labor-intensive, and inefficient. Other... One approach involves manually and repeatedly adjusting the ink volume curves of each color channel in the second printing press based on the color differences between the first and second printing presses, then printing images for comparison. In this case, the quality of color matching is highly dependent on the number of adjustments, the experience and skill of the technicians, resulting in significant uncertainty, low efficiency, and high time and labor costs. Another method involves comparing the output images from the first and second printing presses and manually adjusting the pixel values ​​of the second printing press based on the comparison results. This method is only suitable for small production runs. If a large number of images need to be printed, the technicians need to process each image individually, leading to a huge workload. Therefore, finding a simple and efficient way to perform color matching on printing presses to ensure consistent output colors across all presses has been a problem that those skilled in the art have been striving to solve. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a printing press color matching method, apparatus, device and storage medium based on image processing, to solve the problems of complex and inefficient color matching processing in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a color matching method for printing presses based on image processing, the method comprising:

[0005] Control the first and second printing presses to print preset color mark images to obtain the first and second color mark images respectively;

[0006] The first sampled image and the second sampled image are obtained by acquiring the first color mark image and the second color mark image respectively using the same image acquisition device;

[0007] A first lookup table and a second lookup table are obtained based on the preset color mark image, the first sampling image, and the second sampling image;

[0008] The first image is processed according to the first lookup table and the second lookup table to obtain the second image;

[0009] The first image and the second image are respectively input into the first printing press and the second printing press for printing.

[0010] Preferably, the preset color chart includes N color blocks with different color values, where N is a natural number greater than or equal to 1.

[0011] Preferably, the first printing machine and the second printing machine are any one of inkjet digital printing machine, offset printing machine, gravure printing machine, letterpress printing machine, and screen printing machine.

[0012] Preferably, before controlling the first printing press and the second printing press to print preset color mark images to obtain the first color mark image and the second color mark image, the method further includes:

[0013] The color gamuts of the first printing press and the second printing press are obtained respectively, and are denoted as the first printing press color gamut and the second printing press color gamut;

[0014] The number N of color blocks and the color of each color block are determined based on the intersection area of ​​the first printing press color gamut and the second printing press color gamut.

[0015] The preset color chart is constructed based on the number N of color blocks and the colors of the color blocks.

[0016] Preferably, obtaining the first lookup table and the second lookup table based on the preset color mark image, the first sampling image, and the second sampling image includes:

[0017] Obtain the color data of each color block in the preset color mark image, the first sampling image, and the second sampling image, and record them as preset color data, first sampling color data, and second sampling color data, respectively.

[0018] Establish a mapping relationship between the preset color data and the first sampled color data, and generate the first lookup table, wherein the first lookup table includes a first forward lookup table mapping the preset color data to the first sampled color data and a first reverse lookup table mapping the first sampled color data to the preset color data;

[0019] A mapping relationship is established between the preset color data and the second sampled color data, and a second lookup table is generated. The second lookup table includes a second forward lookup table mapping the preset color data to the second sampled color data and a second reverse lookup table mapping the second sampled color data to the preset color data.

[0020] Preferably, the step of processing the first image according to the first lookup table and the second lookup table to obtain the second image includes:

[0021] The color data of the first image is obtained and recorded as the first image color data;

[0022] The mapping value corresponding to the first image color data is obtained according to the first forward lookup table in the first lookup table, and is denoted as the intermediate color data.

[0023] The mapping value corresponding to the intermediate color data is obtained according to the second reverse lookup table in the second lookup table, and is denoted as the second image color data;

[0024] The second image is obtained by adjusting the color of the first image based on the color data of the second image.

[0025] Preferably, the image acquisition device is any one of a scanner, camera, or video camera.

[0026] Preferably, the first printing press and the second printing press are different printing presses, or the first printing press and the second printing press are the same printing press, and the second printing press is the first printing press that has been used for a period of time.

[0027] Secondly, embodiments of the present invention provide a color-tracking device for a printing press based on image processing, the device comprising:

[0028] The control module is used to control the first printing press and the second printing press to print preset color mark images to obtain the first color mark image and the second color mark image, respectively;

[0029] The acquisition module is used to acquire the first color mark image and the second color mark image respectively using the same image acquisition device to obtain the first sample image and the second sample image;

[0030] The table creation module is used to obtain a first lookup table and a second lookup table based on the preset color mark image, the first sampling image, and the second sampling image;

[0031] The image processing module is used to process the first image according to the first lookup table and the second lookup table to obtain the second image;

[0032] The printing module inputs the first image and the second image into the first printing press and the second printing press respectively for printing.

[0033] Thirdly, embodiments of the present invention provide a printing press color matching device based on image processing, comprising: at least one processor, at least one memory, and computer program instructions stored in the memory, wherein when the computer program instructions are executed by the processor, the method of the first aspect described above is implemented.

[0034] Fourthly, embodiments of the present invention provide a storage medium storing computer program instructions, which, when executed by a processor, implement the method of the first aspect described above.

[0035] In summary, the beneficial effects of the present invention are as follows:

[0036] The image processing-based color matching method, apparatus, device, and storage medium provided in this invention involve controlling a first printing press and a second printing press to print preset color mark images to obtain a first color mark image and a second color mark image, respectively; then, using the same image acquisition device, acquiring the first and second color mark images to obtain a first sample image and a second sample image; obtaining a first lookup table and a second lookup table based on the preset color mark image, the first sample image, and the second sample image; processing a first image based on the first and second lookup tables to obtain a second image; and then inputting the first image and the second image into the first and second printing presses respectively for printing to obtain a printed image with consistent colors. This method is simple and fast, completes color matching without changing the state of the printing press, saves time and effort, and has high color matching efficiency. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of the present invention.

[0038] Figure 1 This is a flowchart illustrating the color matching method for printing presses based on image processing, according to an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of a preset color code diagram according to an embodiment of the present invention.

[0040] Figure 3a This is a schematic diagram of the first and second printing press color gamuts according to an embodiment of the present invention.

[0041] Figure 3bThis is a schematic diagram of the first and second printing press color gamuts according to an embodiment of the present invention.

[0042] Figure 3c This is a schematic diagram of the first and second printing press color gamuts according to an embodiment of the present invention.

[0043] Figure 4 This is a schematic diagram of the structure of a printing press color tracking device based on image processing according to an embodiment of the present invention.

[0044] Figure 5 This is a schematic diagram of the structure of a printing press color matching device based on image processing according to an embodiment of the present invention. Detailed Implementation

[0045] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] Example 1

[0048] This invention provides an image processing-based color matching method for printing presses, applicable to color matching processing of printing presses. The printing press here refers to any one of the following: digital inkjet printing press, offset printing press, gravure printing press, letterpress printing press, and screen printing press. The first and second printing presses are of the same type.

[0049] In actual production applications, it is often required that several printing presses can print sample prints with the same color as a target printing press. Therefore, it is necessary to perform color matching processing on several printing presses. Here, the target printing press is referred to as the first printing press, and the printing press that needs to be subjected to color matching processing is referred to as the second printing press.

[0050] It is worth noting that the first printing press and the second printing press can be different printing presses or the same printing press.

[0051] In some embodiments, the first printing press is a proofing machine used to print a sample of an image, and the second printing press is the printing press used in actual production. In actual production, the printing press needs to use the image sample printed by the proofing machine as the target, and the printed image needs to be consistent with the color of the sample. Therefore, it is necessary to perform color matching processing on the second printing press with the first printing press as the color matching target.

[0052] In some embodiments, the usage time of the first printing press is longer than that of the second printing press. The first and second printing presses can be the same model manufactured by the same manufacturer, or they can be different models manufactured by different manufacturers. The first printing press is put into actual production application before the second printing press. After the user has used the first printing press to perform printing tasks for a period of time, the second printing press is added to perform the same printing tasks to improve printing efficiency. At this time, it is necessary to perform color matching processing on the second printing press with the first printing press as the color matching target to ensure that the printed colors are consistent when performing the same printing tasks.

[0053] In some embodiments, the first printing press and the second printing press are manufactured by different manufacturers. In practical applications, the first printing press and the second printing press manufactured by different manufacturers may be used simultaneously to perform the same printing task. Since the differences in hardware and software of printing presses manufactured by different manufacturers can cause the final printed image to have different colors even when printing the same image, it is necessary to perform color matching processing on the first printing press or the second printing press to ensure that the printing color is consistent when performing the same printing task.

[0054] In some embodiments, the first printing press and the second printing press are the same printing press, with the second printing press being the first printing press that has been used for a period of time. In actual production applications, product orders placed a few days or months ago are often re-produced (also known as reorders), requiring the printing of a batch of images with the same colors as the previous orders. During this period, the machine status, ink batch, and printhead status may change (e.g., changes in the machine's environment, ink batch, or wear and tear on the printhead due to prolonged use), resulting in significant color differences between the images printed on the same printing press after a certain period of time when performing the same printing task. If a printing press (referred to as the first printing press) performed a printing task some time ago, and this printing press (referred to as the second printing press) needs to perform a reorder some time later, then color matching processing is required for the second printing press to ensure consistent printing colors when performing the same printing task before and after the previous period.

[0055] Please see Figure 1 The image processing-based color matching method for printing presses includes the following steps:

[0056] S1: Control the first printing press and the second printing press to print the preset color mark image to obtain the first color mark image and the second color mark image respectively;

[0057] S2: Use the same image acquisition device to acquire the first color mark image and the second color mark image respectively to obtain the first sample image and the second sample image;

[0058] S3: Obtain a first lookup table and a second lookup table based on the preset color mark image, the first sampling image, and the second sampling image;

[0059] S4: Process the first image according to the first lookup table and the second lookup table to obtain the second image;

[0060] S5: Input the first image and the second image into the first printing press and the second printing press respectively for printing.

[0061] The first color chart here is an image recorded in electronic document format. It can be an international standard color chart image (such as IT8.7-2 / 1993), or an image designed by the user according to actual application requirements. Preferably, the first color chart is a color image comprising N color patches with different color values, where N is a natural number greater than or equal to 1. The color values ​​of the color patches can be RGB values ​​or CMYK values. For example, ... Figure 2As shown, the first color chart contains multiple color blocks with different RGB values. Each color block has at least one color channel (R, G, and B) whose value differs from the other color blocks. The first color chart should contain as many color blocks with different color values ​​as possible. The more color blocks with different color values, the richer the color data contained in the first color chart, and the more accurate the subsequent color conversion will be based on the first and second lookup tables built from this color data. Preferably, N is greater than or equal to 3000. In one embodiment, R, G, and B values ​​are selected every 15 intervals from 0 to 255, i.e., R = {0, 15, 30, ..., 255}, G = {0, 15, 30, ..., 255}, B = {0, 15, 30, ..., 255}. The R, B, and G values ​​are permuted and combined to obtain 4913 color values. Corresponding color blocks are generated based on these 4913 color values ​​to obtain the first color chart. In other embodiments, R, G, and B values ​​can be selected at intervals of 1, 2, 5, 10, etc., and the color values ​​can be arranged and combined to obtain corresponding color blocks to form a first color chart. For example, R, G, and B values ​​are selected at intervals of 1 from 0 to 255, i.e., R = {0, 1, 2, ..., 255}, G = {0, 1, 2, ..., 255}, B = {0, 1, 2, ..., 255}. The R, B, and G values ​​are then arranged and combined to obtain 256. 3 The color values ​​are calculated and corresponding color blocks are generated to obtain the first color mark map.

[0062] In other embodiments, the C, M, Y, and K values ​​from the CMYK four-color channels can be selected at intervals of 1, 2, 3, 5, 10, etc., and the color values ​​can be arranged and combined to obtain corresponding color blocks to form a first color chart. For example, C, M, Y, and K values ​​are selected at intervals of 1 from 0 to 100, i.e., C = {0, 1, 2, ..., 100}, M = {0, 1, 2, ..., 100}, Y = {0, 1, 2, ..., 100}, K = {0, 1, 2, ..., 100}, and the CMYK values ​​are arranged and combined to obtain a color chart consisting of 101... 4 The first color chart consists of color blocks with color values.

[0063] In other embodiments, digital printing presses used in the digital printing industry, in addition to the CMYK four-color channels, also have several spot color channels for printing spot color inks. Therefore, the C, M, Y, and K values ​​in the CMYK four-color channels can be selected at intervals of 1, 2, 3, 5, 10, etc., and the color values ​​of the spot color channels can be arranged and combined to obtain corresponding color blocks to form a first color chart. For example, suppose the printing press also includes a spot color channel P, and the C, M, Y, K, and P values ​​are selected at intervals of 2 from 0-100, i.e., C = {0, 2, 4, ..., 100}, M = {0, 2, 4, ..., 100}, Y = {0, 2, 4, ..., 100}, K = {0, 2, 4, ..., 100}, P = {0, 2, 4, ..., 100}. The CMYK P values ​​are arranged and combined to obtain a color chart consisting of 51... 5 A first color swatch image composed of color blocks. In one embodiment, the first color swatch image is determined based on the color gamut of a first printing press and the color gamut of a second printing press. Preferably, before controlling the first and second printing presses to print the preset color swatch image to obtain the first and second color swatch images respectively, the method further includes:

[0064] The color gamuts of the first printing press and the second printing press are obtained respectively, and are denoted as the first printing press color gamut and the second printing press color gamut;

[0065] The number N of color blocks and the color of each color block are determined based on the intersection area of ​​the first printing press color gamut and the second printing press color gamut.

[0066] The preset color chart is constructed based on the number N of color blocks and the colors of the color blocks.

[0067] The first and second printing press color gamuts refer to the color gamuts that the first and second printing presses can display in the Lab color space. When the second printing press is different from the first, the two color gamuts will differ. Even if the second and first printing presses are the same press, but the second press is a version of the first press that has been used for a period of time, due to wear and tear, equipment aging, etc., the color gamut of the second press will change compared to its earlier version, thus the two color gamuts will also differ. The first and second printing press color gamuts can be directly obtained using ICC viewers, color gamut viewers, or user-defined color gamut viewers.

[0068] like Figure 3a , Figure 3b and Figure 3c The diagram illustrates three topological relationships between the first printing press color gamut 10 and the second printing press color gamut 20. Figure 3aIn this process, there is partial overlap between the first printing press color gamut 10 and the second printing press color gamut 20, and partial non-overlap. The topological relationship between the first printing press color gamut 10 and the second printing press color gamut 20 is "intersecting". Therefore, the intersecting area between the first and second printing press color gamuts is the overlapping area. Figure 3b In this embodiment, the first printing press color gamut 10 is included within the second printing press color gamut 20. In this case, the second printing press color gamut 20 "includes" the first printing press color gamut 10. The topological relationship between the second printing press color gamut 20 and the first printing press color gamut 10 is "inclusion." The intersection area of ​​the first and second printing press color gamuts is the second printing press color gamut. If color matching processing is performed between the two, the first printing press color gamut should be the target. In other embodiments, the second printing press color gamut may be included within the first printing press color gamut. In this case, if color matching processing is performed between the two, the second printing press color gamut should be the target. Figure 3c In the diagram, the first printing press color gamut 10 and the second printing press color gamut 20 have no overlapping or intersecting parts, and their topological relationship is "non-inclusive". In actual printing applications, if the topological relationship between the first and second printing press color gamuts is non-inclusive, then the colors printed by the first and second printing presses will not be consistent. In this case, color matching processing performed on the printing presses is meaningless. Therefore, only when the topological relationship between the first and second printing press color gamuts is intersecting or inclusive, that is, when there is an overlapping part between the two color gamuts, can the colors printed by the first and second printing presses be consistent. In other words, color matching processing can ensure that the first and second printing presses print consistent colors.

[0069] Preferably, a preset color chart is constructed using the number and color of sampling points in the intersection region of the first and second printing press color gamuts. Specifically, sampling is performed on the intersection region of the first and second printing press color gamuts, with each sampling point corresponding to a color value (in the Lab color space, the color value of the sampling point is a Lab value, which can be converted to a CMYK or RGB value). A preset color chart is constructed based on the color value of each sampling point and the number of sampling points. The more sampling points, the more color information is contained in the preset color chart, and the more accurate the color conversion is when using the first and second lookup tables built based on this color data. Suppose N sampling points are determined from the printing press color gamut, the Lab values ​​corresponding to these N sampling points are obtained, and the Lab values ​​are converted to CMYK or RGB values. A color block is constructed for each sampling point, and all color blocks constitute the preset color chart.

[0070] After obtaining the preset color mark image, the first and second printing presses are controlled to print the preset color mark image onto the printing medium, respectively, to obtain the first color mark image and the second color mark image. An image acquisition device is used to acquire the first color mark image on the printing medium to obtain an electronic image of the first color mark image, denoted as the first sampling image. The same image acquisition device is used to acquire the second color mark image on the printing medium to obtain an electronic image of the second color mark image, denoted as the second sampling image. Then, a first lookup table and a second lookup table for color conversion are generated based on the preset color mark image, the first sampling image, and the second sampling image. It is worth noting that the same image acquisition device is used for acquiring the first and second color mark images to ensure consistency in color data acquisition. The image acquisition device can be any one of a CCD / CMOS scanner, a CCD / CMOS camera, or a CCD / CMOS camcorder.

[0071] Preferably, obtaining the first lookup table and the second lookup table based on the preset color mark image, the first sampling image, and the second sampling image includes:

[0072] Obtain the color data of each color block in the preset color mark image, the first sampling image, and the second sampling image, and record them as preset color data, first sampling color data, and second sampling color data, respectively.

[0073] Establish a mapping relationship between the preset color data and the first sampled color data, and generate the first lookup table, wherein the first lookup table includes a first forward lookup table mapping the preset color data to the first sampled color data and a first reverse lookup table mapping the first sampled color data to the preset color data;

[0074] A mapping relationship is established between the preset color data and the second sampled color data, and a second lookup table is generated. The second lookup table includes a second forward lookup table mapping the preset color data to the second sampled color data and a second reverse lookup table mapping the second sampled color data to the preset color data.

[0075] The preset color mark image, the first sample image, and the second sample image are all electronic images. Color data for each color block in the preset color mark image, the first sample image, and the second sample image are acquired using image processing software on a host computer. Preset color data, first sample color data, and second sample color data are then generated. The color data can be either RGB or CMYK data. Preferably, the preset color data, the first sample color data, and the second sample color data are all RGB data.

[0076] Since both the first and second sampled images are obtained based on a pre-defined color mark image, there is a one-to-one mapping between the pre-defined color data in the pre-defined color mark image and the first color data in the first sampled image. A first forward lookup table is generated based on this mapping (e.g., through interpolation), and a first reverse lookup table is generated based on this mapping (again, through interpolation). The first forward lookup table and the first reverse lookup table together form the first lookup table. Similarly, there is a one-to-one mapping between the pre-defined color data in the pre-defined color mark image and the second color data in the second sampled image. A second forward lookup table is generated based on this mapping, and a second reverse lookup table is generated based on this mapping. The second forward lookup table and the second reverse lookup table together form the second lookup table.

[0077] When the first printing press prints the first image, if the second printing press directly prints the same first image, the colors of the images printed by the two presses will differ. Therefore, when printing the first image using the first printing press, the first lookup table and the second lookup table are used to adjust the first image. The adjusted first image (denoted as the second image) is then input into the second printing press for printing (the first printing press still prints the original first image), so that the colors of the images printed by the two presses are consistent.

[0078] Preferably, the step of processing the first image according to the first lookup table and the second lookup table to obtain the second image includes:

[0079] The color data of the first image is obtained and recorded as the first image color data;

[0080] The mapping value corresponding to the first image color data is obtained according to the first forward lookup table in the first lookup table, and is denoted as the intermediate color data.

[0081] The mapping value corresponding to the intermediate color data is obtained according to the second reverse lookup table in the second lookup table, and is denoted as the second image color data;

[0082] The second image is obtained by adjusting the color of the first image based on the color data of the second image.

[0083] The first image here is an electronic image. In other embodiments, if the first image is a physical image, an image acquisition device can be used to convert the first image (physical image) into an electronic image before acquiring its color data. The color data of each color in the first image is recorded as the first image color data; preferably, the first image color data is RGB data. The mapping value corresponding to the first image color data is obtained according to the first forward lookup table in the first lookup table, and this mapping value is recorded as the intermediate color data. Then, the mapping value corresponding to the intermediate color data is obtained from the second reverse lookup table in the second lookup table, and recorded as the second color data. The second image is obtained based on the second color data; the second image is an image after adjusting the color data in the first image. The first image is input into the first printing press, and the second image is input into the second printing press for printing, resulting in a first printed image and a second printed image with consistent colors.

[0084] In one embodiment, the first lookup table and the second lookup table are integrated into the image processing software of the host computer (such as ImageMaster). When the second printing press needs to perform color matching printing with the first printing press as the color matching target, the first image to be printed by the first printing press is input into the image processing software of the host computer, the image processing software outputs the second image, and then the first image and the second image are sent to the first printing press and the second printing press for printing, respectively.

[0085] Furthermore, it is worth noting that the first printing press can be one or more printing presses, and the second printing press can also be one or more printing presses. For example, the first printing press includes one printing press for printing the first image, and the second printing press includes multiple printing presses, such as second printing press A and second printing press B. A first lookup table A and a second lookup table A corresponding to second printing press A are obtained respectively. The second image A is obtained using the first lookup table A and the second lookup table A. Similarly, a first lookup table B and a second lookup table B corresponding to second printing press B are obtained using the first lookup table B and the second lookup table B. Then, the first printing press is controlled to print the first image, the second printing press A to print the second image A, and the second printing press B to print the second image B, resulting in a first printed image and a second printed image with consistent colors (A and B). The number of the first and second printing presses can be determined according to the actual situation and is not limited further. The image processing-based printing press color matching method of this embodiment can perform color matching processing on multiple printing presses, making the output colors of multiple printing presses consistent.

[0086] Unlike existing technologies that rely on adjusting the printing press's color management profile or ink volume curve to change the printing press's state and achieve consistent output colors, the image processing-based printing press color matching method of this invention starts by inputting images from a first printing press and a second printing press. The first and second printing presses then print a first image and a second image adjusted based on the first image, respectively. This achieves consistent output colors for both printing presses without needing to adjust their color management profiles or ink volume curves. This method is simple, fast, and completes color matching without changing the printing press's state, saving time and effort while achieving high color matching efficiency.

[0087] In summary, the image processing-based color matching method for printing presses provided by this invention involves controlling a first printing press and a second printing press to print preset color mark images to obtain a first color mark image and a second color mark image, respectively; then, using the same image acquisition device, acquiring the first color mark image and the second color mark image to obtain a first sample image and a second sample image; obtaining a first lookup table and a second lookup table based on the preset color mark image, the first sample image, and the second sample image; processing the first image based on the first lookup table and the second lookup table to obtain a second image; and then inputting the first image and the second image into the first printing press and the second printing press, respectively, for printing to obtain a printed image with consistent colors. This method is simple and fast, completes color matching without changing the state of the printing press, saves time and effort, and has high color matching efficiency.

[0088] Example 2

[0089] Please see Figure 4 This invention provides a color-tracking device 200 for a printing press based on image processing. The device 200 includes:

[0090] Control module 201 is used to control the first printing press and the second printing press to print preset color mark images to obtain the first color mark image and the second color mark image respectively;

[0091] The acquisition module 202 is used to acquire the first color mark image and the second color mark image respectively using the same image acquisition device to obtain the first sample image and the second sample image;

[0092] The table creation module 203 is used to obtain a first lookup table and a second lookup table based on the preset color mark image, the first sampling image, and the second sampling image;

[0093] Image processing module 204 is used to process the first image according to the first lookup table and the second lookup table to obtain the second image;

[0094] The printing module 205 inputs the first image and the second image into the first printing machine and the second printing machine, respectively, for printing.

[0095] Preferably, the device 200 further includes:

[0096] The color gamut acquisition module is used to acquire the color gamuts of the first printing press and the second printing press respectively, denoted as the first printing press color gamut and the second printing press color gamut;

[0097] The number determination module is used to determine the number N of color blocks and the color of each color block based on the intersection area of ​​the first printing machine color gamut and the second printing machine color gamut.

[0098] A construction module is used to construct the preset color chart based on the number N of color blocks and the colors of the color blocks.

[0099] Preferably, the table creation module 203 includes:

[0100] The color data acquisition unit is used to acquire the color data of each color block in the preset color mark image, the first sampling image and the second sampling image, which are respectively denoted as preset color data, first sampling color data and second sampling color data;

[0101] The first table building unit is used to establish a mapping relationship between the preset color data and the first sampled color data, and generate the first lookup table, wherein the first lookup table includes a first forward lookup table mapping the preset color data to the first sampled color data and a first reverse lookup table mapping the first sampled color data to the preset color data.

[0102] The second table building unit is used to establish the mapping relationship between the preset color data and the second sampled color data, and generate the second lookup table. The second lookup table includes a second forward lookup table mapping the preset color data to the second sampled color data and a second reverse lookup table mapping the second sampled color data to the preset color data.

[0103] Preferably, the image processing module 204 includes:

[0104] The first image color data acquisition unit is used to acquire the color data of the first image, which is denoted as the first image color data.

[0105] The first lookup unit is used to obtain the mapping value corresponding to the first image color data according to the first forward lookup table in the first lookup table, and denoted as the intermediate color data;

[0106] The second lookup unit is used to obtain the mapping value corresponding to the intermediate color data according to the second reverse lookup table in the second lookup table, which is denoted as the second image color data.

[0107] An adjustment unit is used to adjust the color of the first image according to the color data of the second image to obtain the second image.

[0108] In summary, the image processing-based color matching device for printing presses provided in this embodiment of the invention obtains a first color mark image and a second color mark image by controlling a first printing press and a second printing press to print preset color mark images respectively; then, the same image acquisition device is used to acquire the first color mark image and the second color mark image respectively to obtain a first sample image and a second sample image; a first lookup table and a second lookup table are obtained based on the preset color mark image, the first sample image, and the second sample image; and the first image is processed according to the first lookup table and the second lookup table to obtain a second image; then, the first image and the second image are respectively input into the first printing press and the second printing press for printing to obtain a printed image with consistent colors. This method is simple and fast, completes color matching without changing the state of the printing press, saves time and effort, and has high color matching efficiency.

[0109] Example 3

[0110] In addition, the printing press color matching method based on image processing in this embodiment of the invention can be implemented by a printing press color matching device based on image processing. Figure 5 A schematic diagram of the hardware structure of a printing press color matching device based on image processing provided in an embodiment of the present invention is shown.

[0111] Image processing-based color matching equipment for printing presses may include a processor 301 and a memory 302 storing computer program instructions.

[0112] Specifically, the processor 301 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of the present invention.

[0113] Memory 302 may include mass storage for data or instructions. For example, and not limitingly, memory 302 may include a hard disk drive (HDD), a floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 302 may include removable or non-removable (or fixed) media. Where appropriate, memory 302 may be internal or external to a data processing device. In a particular embodiment, memory 302 is a non-volatile solid-state memory. In a particular embodiment, memory 302 includes read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0114] The processor 301 reads and executes computer program instructions stored in the memory 302 to implement any of the image processing-based color matching methods for printing presses in the above embodiments.

[0115] In one example, the image processing-based printing press color matching device may also include a communication interface 303 and a bus 310. For example, Figure 5 As shown, the processor 301, memory 302, and communication interface 303 are connected through bus 310 and complete communication with each other.

[0116] The communication interface 303 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of the present invention.

[0117] Bus 310 includes hardware, software, or both, that couples components of an image-processing-based printing press color-matching device together. For example, and not limitingly, bus 310 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 310 may include one or more buses. Although specific buses are described and illustrated in embodiments of the invention, the invention contemplates any suitable bus or interconnect.

[0118] Example 4

[0119] Furthermore, in conjunction with the image processing-based printing press color matching method in the above embodiments, this invention can be implemented using a computer-readable storage medium. This computer-readable storage medium stores computer program instructions; when executed by the processor 301, these computer program instructions implement any of the image processing-based printing press color matching methods in the above embodiments.

[0120] In summary, the image processing-based color matching method, apparatus, device, and storage medium provided in this invention involve controlling a first printing press and a second printing press to print preset color mark images to obtain a first color mark image and a second color mark image, respectively; then, using the same image acquisition device to acquire the first color mark image and the second color mark image to obtain a first sample image and a second sample image; obtaining a first lookup table and a second lookup table based on the preset color mark image, the first sample image, and the second sample image; processing the first image based on the first lookup table and the second lookup table to obtain a second image; and then inputting the first image and the second image into the first printing press and the second printing press respectively for printing to obtain a printed image with consistent colors. This method is simple and fast, completes color matching without changing the state of the printing press, saves time and effort, and has high color matching efficiency.

[0121] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0122] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the required tasks. The programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0123] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0124] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A color matching method for printing presses based on image processing, characterized in that, The method includes: Control the first and second printing presses to print preset color mark images to obtain the first and second color mark images respectively; The first sampled image and the second sampled image are obtained by acquiring the first color mark image and the second color mark image respectively using the same image acquisition device; A first lookup table and a second lookup table are obtained based on the preset color mark image, the first sampling image, and the second sampling image; The first image is processed according to the first lookup table and the second lookup table to obtain the second image; The first image and the second image are respectively input into the first printing press and the second printing press for printing; The preset color chart includes N color blocks with different color values, where N is a natural number greater than or equal to 1; Before controlling the first and second printing presses to print preset color mark images to obtain the first and second color mark images, the process also includes: The color gamuts of the first printing press and the second printing press are obtained respectively, and are denoted as the first printing press color gamut and the second printing press color gamut; The number N of color blocks and the color of each color block are determined based on the intersection area of ​​the first printing press color gamut and the second printing press color gamut. The intersecting region is the area where the first printing press color gamut and the second printing press color gamut overlap. The preset color chart is constructed based on the number N of color blocks and the colors of the color blocks; The step of obtaining the first lookup table and the second lookup table based on the preset color mark image, the first sampling image, and the second sampling image includes: Obtain the color data of each color block in the preset color mark image, the first sampling image, and the second sampling image, and record them as preset color data, first sampling color data, and second sampling color data, respectively. Establish a mapping relationship between the preset color data and the first sampled color data, and generate the first lookup table, wherein the first lookup table includes a first forward lookup table mapping the preset color data to the first sampled color data and a first reverse lookup table mapping the first sampled color data to the preset color data; Establish a mapping relationship between the preset color data and the second sampled color data, and generate the second lookup table, wherein the second lookup table includes a second forward lookup table mapping the preset color data to the second sampled color data and a second reverse lookup table mapping the second sampled color data to the preset color data; The step of processing the first image according to the first lookup table and the second lookup table to obtain the second image includes: The color data of the first image is obtained and recorded as the first image color data; The mapping value corresponding to the first image color data is obtained according to the first forward lookup table in the first lookup table, and is denoted as the intermediate color data. The mapping value corresponding to the intermediate color data is obtained according to the second reverse lookup table in the second lookup table, and is denoted as the second image color data; The second image is obtained by adjusting the color of the first image based on the color data of the second image.

2. The printing press color matching method based on image processing according to claim 1, characterized in that, Both the first printing press and the second printing press are any one of inkjet digital printing press, offset printing press, gravure printing press, letterpress printing press, and screen printing press.

3. The printing press color matching method based on image processing according to any one of claims 1-2, characterized in that, The first printing press and the second printing press are different printing presses, or the first printing press and the second printing press are the same printing press, and the second printing press is the first printing press that has been used for a period of time.

4. A color-tracking device for a printing press based on image processing, characterized in that, The device includes: The control module is used to control the first printing press and the second printing press to print preset color mark images to obtain the first color mark image and the second color mark image, respectively; The acquisition module is used to acquire the first color mark image and the second color mark image respectively using the same image acquisition device to obtain the first sample image and the second sample image; The table creation module is used to obtain a first lookup table and a second lookup table based on the preset color mark image, the first sampling image, and the second sampling image; The image processing module is used to process the first image according to the first lookup table and the second lookup table to obtain the second image; A printing module is used to input the first image and the second image into the first printing press and the second printing press respectively for printing; The preset color chart includes N color blocks with different color values, where N is a natural number greater than or equal to 1; Before controlling the first and second printing presses to print preset color mark images to obtain the first and second color mark images, the process also includes: The color gamuts of the first printing press and the second printing press are obtained respectively, and are denoted as the first printing press color gamut and the second printing press color gamut; The number N of color blocks and the color of each color block are determined based on the intersection area of ​​the first printing press color gamut and the second printing press color gamut. The intersecting region is the area where the first printing press color gamut and the second printing press color gamut overlap. The preset color chart is constructed based on the number N of color blocks and the colors of the color blocks; The step of obtaining the first lookup table and the second lookup table based on the preset color mark image, the first sampling image, and the second sampling image includes: Obtain the color data of each color block in the preset color mark image, the first sampling image, and the second sampling image, and record them as preset color data, first sampling color data, and second sampling color data, respectively. Establish a mapping relationship between the preset color data and the first sampled color data, and generate the first lookup table, wherein the first lookup table includes a first forward lookup table mapping the preset color data to the first sampled color data and a first reverse lookup table mapping the first sampled color data to the preset color data; Establish a mapping relationship between the preset color data and the second sampled color data, and generate the second lookup table, wherein the second lookup table includes a second forward lookup table mapping the preset color data to the second sampled color data and a second reverse lookup table mapping the second sampled color data to the preset color data; The step of processing the first image according to the first lookup table and the second lookup table to obtain the second image includes: The color data of the first image is obtained and recorded as the first image color data; The mapping value corresponding to the first image color data is obtained according to the first forward lookup table in the first lookup table, and is denoted as the intermediate color data. The mapping value corresponding to the intermediate color data is obtained according to the second reverse lookup table in the second lookup table, and is denoted as the second image color data; The second image is obtained by adjusting the color of the first image based on the color data of the second image.

5. A color-tracking device for a printing press based on image processing, characterized in that, include: At least one processor, at least one memory, and computer program instructions stored in the memory, which, when executed by the processor, implement the method as described in any one of claims 1-3.

6. A storage medium storing computer program instructions thereon, characterized in that, When the computer program instructions are executed by a processor, the method as described in any one of claims 1-3 is implemented.

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