Color matching method, device, equipment and storage medium for printing equipment

Abstract

The application discloses a color tracking method and device for a printing apparatus, an apparatus and a storage medium, and relates to the field of inkjet printing technology. The method comprises the following steps: obtaining a second image by performing image processing on a first image to be printed according to a preset color tracking curve through a preset raster image device; performing raster processing on the first image and the second image respectively and sending the first image and the second image to corresponding first and second printing apparatuses for printing, so that a printed image with consistent colors is obtained. The method is equivalent to adding a preset raster image processing device at the front end of a raster image processing device of a host computer, and the color tracking process is completed in the preset raster image processing device, so that repeated adjustment of a color management curve of the second printing apparatus for color tracking is avoided, color matching is completed without changing the state of the apparatus, the threshold for an operator is greatly reduced, and enterprise costs are saved.

Description

Technical Field

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

[0002] In the printing industry, to ensure the color output of printing equipment, color management is necessary. This includes creating color management profiles for each printing machine to control the overall printing color effect. In practical production applications, when the output color of one or more secondary printing machines is required to match that of the primary printing machine, the output color of the secondary machines needs to be adjusted with the primary machine as the target for color matching—that is, color matching processing of the secondary machines. Current technologies often use the color management profile of the primary machine as the target, adjusting the color management profile of the secondary machines using RIP software to control the ink output of each channel of the secondary machine, thereby ensuring color consistency with the primary machine. However, this method is highly dependent on the experience level of the debugging personnel (e.g., their familiarity with different printing machines and RIP software), resulting in high uncertainty, low efficiency, and significant time and effort required. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a method, apparatus, device and storage medium for color matching in printing equipment, in order to solve the problems of complex and uncertain color matching processes in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a color matching method for printing equipment, the method comprising:

[0005] Construct a preset color matching curve for the second printing equipment relative to the first printing equipment;

[0006] The preset raster image processing device is controlled to process the first image according to the preset color tracking curve to obtain the second image, wherein both the first image and the second image are bitmaps;

[0007] The first raster image processing device is controlled to perform rasterization processing on the first image and the second image respectively to obtain the first raster dot matrix image and the second raster dot matrix image;

[0008] The first raster dot matrix image and the second raster dot matrix image are sent to the first printing equipment and the second printing equipment, respectively, for printing.

[0009] Preferably, the control preset raster image processing device processes the first image according to the preset color matching curve to obtain the second image, including:

[0010] The preset raster image processing device is controlled to perform rasterization processing on the first image according to the preset color tracking curve to obtain a preset raster dot matrix image;

[0011] The preset raster dot matrix image is converted into a bitmap to obtain the second image.

[0012] Preferably, the construction of the preset color matching curve of the second printing equipment relative to the first printing equipment includes:

[0013] The first printing equipment is controlled to print a preset color block image to obtain a first color block image; wherein, the preset color block image includes several color blocks with different ink amounts;

[0014] The second printing equipment is controlled to print the preset color block image to obtain the second color block image;

[0015] The ink volume of the second printing device is obtained based on the first color block image and the second color block image.

[0016] Based on the ink volume cut-off, the second printing equipment is controlled to reprint the preset color block image to obtain a third color block image;

[0017] The preset color-tracking curve is obtained based on the first color block image and the third color block image.

[0018] Preferably, obtaining the ink volume of the second printing device based on the first color block image and the second color block image includes:

[0019] Obtain the color value of the color block with the largest ink volume in the first color block image, and record it as the first maximum color value;

[0020] The color block with the smallest color difference value compared with the first maximum color value in the second color block image is recorded as the ink cut-off color block;

[0021] The amount of ink in the cut-off ink patch is the cut-off ink volume.

[0022] Preferably, obtaining the preset color matching curve based on the first color block image and the third color block image includes:

[0023] Obtain the color difference value between each color block in the third color block image and the color block with the smallest ink amount in the first color block image, and obtain the ink amount of each color block in the third color block image and its corresponding color difference value, which is denoted as the first color difference set;

[0024] Obtain the color difference value between each color block in the first color block image and the color block with the smallest ink amount in the first color block image, and obtain the set of ink amount of each color block in the first color block image and its corresponding color difference value, which is denoted as the second color difference set;

[0025] The preset color matching curve is obtained based on the first color difference set and the second color difference set.

[0026] Preferably, obtaining the preset color matching curve based on the first color difference set and the second color difference set includes:

[0027] The elements in the first color difference set are fitted to obtain the first fitting curve;

[0028] Obtain the ink volume of the color blocks in all elements of the second color difference set, and denote it as the first ink volume;

[0029] Based on the first fitted curve, obtain the second ink volume corresponding to the color difference value of all elements in the second color difference set;

[0030] The first ink volume and the second ink volume are fitted to obtain the preset color matching curve.

[0031] Preferably, the first printing equipment and the second printing equipment are any one of inkjet digital printing equipment, offset printing equipment, gravure printing equipment, letterpress printing equipment, and screen printing equipment.

[0032] In a second aspect, embodiments of the present invention provide a color matching device for printing equipment, the device comprising:

[0033] The preset color matching curve construction module is used to construct the preset color matching curve of the second printing equipment relative to the first printing equipment;

[0034] The image processing module is used to control a preset raster image processing device to process the first image according to the preset color tracking curve to obtain a second image, wherein both the first image and the second image are bitmaps;

[0035] The raster processing module is used to control the first raster image processing device to perform rasterization processing on the first image and the second image respectively to obtain the first raster dot matrix image and the second raster dot matrix image;

[0036] The printing module is used to send the first raster dot matrix image and the second raster dot matrix image to the first printing equipment and the second printing equipment, respectively, for printing.

[0037] Thirdly, embodiments of the present invention provide a color matching device for printing equipment, 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.

[0038] 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.

[0039] In summary, the beneficial effects of the present invention are as follows:

[0040] The color matching method, apparatus, device, and storage medium for printing equipment provided in this invention involve processing a first image to be printed using a preset raster image device according to a preset color matching curve to obtain a second image. Then, the first and second images are rasterized and sent to the corresponding first and second printing devices for printing, resulting in a printed image with consistent colors. This method is equivalent to adding a preset raster image processing device in front of the raster image processing device on the host computer, completing the color matching process within this preset raster image processing device. After obtaining the second image with completed color matching, it is sent to the second printing device (which acts as the color matching device) for normal rasterization processing before printing, thus achieving color consistency with the output color of the first image printed by the first printing device. This invention avoids repeatedly adjusting the color management curve of the second printing device for color matching, completing color matching without changing the equipment status, greatly reducing the operator's threshold and saving enterprise costs. Attached Figure Description

[0041] 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.

[0042] Figure 1 This is a schematic flowchart of the color matching method for printing equipment according to an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of a preset color block diagram according to an embodiment of the present invention.

[0044] Figure 3a This is a schematic diagram of the first color block diagram according to an embodiment of the present invention.

[0045] Figure 3b This is a schematic diagram of the second color block diagram according to an embodiment of the present invention.

[0046] Figure 4 This is a schematic diagram of the third color block diagram according to an embodiment of the present invention.

[0047] Figure 5 This is a schematic diagram of the preset color matching curve in an embodiment of the present invention.

[0048] Figure 6 This is a schematic diagram of the color matching device of the printing equipment according to an embodiment of the present invention.

[0049] Figure 7 This is a schematic diagram of the color matching device in the printing equipment according to an embodiment of the present invention. Detailed Implementation

[0050] 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.

[0051] 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 additional identical elements in the process, method, article, or apparatus that includes said element.

[0052] Example 1

[0053] This invention provides a color matching method for printing equipment, applicable to color matching processing of printing equipment. The printing equipment referred to here is any one of digital printing equipment, offset printing equipment, gravure printing equipment, letterpress printing equipment, and screen printing equipment.

[0054] In practical production applications, it is often required that several printing machines can print a sample with the same color as a target printing machine. Therefore, color matching processing is needed for these machines. Here, the target printing machine is referred to as the first printing machine, and the printing machine requiring color matching processing is referred to as the second printing machine. Generally, color matching between the two machines can be achieved as long as their color gamuts overlap. Preferably, using a printing machine with a larger color gamut to perform color matching on a printing machine with a smaller color gamut yields better results.

[0055] It is worth noting that the first printing equipment and the second printing equipment can be of the same type, for example, both of them can be digital printing equipment. Alternatively, the first printing equipment and the second printing equipment can be of different types, such as the first printing equipment being a offset printing equipment and the second printing equipment being a digital printing equipment. Furthermore, the first printing equipment and the second printing equipment can also be the same printing equipment.

[0056] In some embodiments, the first printing equipment is a proofing machine (e.g., a digital printing machine) used to print a sample of an image, and the second printing equipment is the printing equipment used in actual production (e.g., a offset printing machine). In actual production, the printing equipment needs to target the image sample printed by the proofing machine, and the printed image needs to match the color of the sample. Therefore, the second printing equipment needs to perform color matching processing with the first printing equipment as the color matching target.

[0057] In some embodiments, the usage time of the first printing equipment is longer than that of the second printing equipment. The first and second printing equipment can be machines of the same model manufactured by the same manufacturer, or they can be machines of different models manufactured by different manufacturers. The first printing equipment is put into actual production application before the second printing equipment. After the user uses the first printing equipment to perform printing tasks for a period of time, the second printing equipment 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 equipment with the first printing equipment as the color matching target to ensure that the printed colors are consistent when performing the same printing tasks.

[0058] In some embodiments, the first printing equipment and the second printing equipment are manufactured by different manufacturers. In practical applications, the first printing equipment and the second printing equipment manufactured by different manufacturers may be used simultaneously to perform the same printing task. Since the differences in hardware and software of printing equipment 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 equipment or the second printing equipment to ensure that the printing color is consistent when performing the same printing task.

[0059] In some embodiments, the first printing equipment and the second printing equipment are the same printing equipment, with the second printing equipment being the first printing equipment after a period of use. 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 printhead wear due to prolonged use), resulting in significant color differences between the images printed on the same printing equipment after a period of time when performing the same printing task. If a printing equipment (referred to as the first printing equipment) performed a printing task some time ago, and this printing equipment (referred to as the second printing equipment) needs to perform a reorder some time later, then color matching processing is required for the second printing equipment to ensure consistent printing colors when performing the same printing task before and after the previous period.

[0060] Please see Figure 1 The color matching method for the printing equipment includes the following steps:

[0061] S1: Construct a preset color matching curve for the second printing equipment relative to the first printing equipment;

[0062] S2: Control the preset raster image processing device to process the first image according to the preset color tracking curve to obtain the second image, wherein both the first image and the second image are bitmaps;

[0063] S3: Control the first raster image processing device to perform rasterization processing on the first image and the second image respectively to obtain the first raster dot matrix image and the second raster dot matrix image;

[0064] S4: Send the first raster dot matrix image and the second raster dot matrix image to the first printing equipment and the second printing equipment respectively for printing.

[0065] Specifically, the first and second printing equipment each have corresponding linearization curves for adjusting the ink output of each color channel. The preset color matching curve of the second printing equipment relative to the first printing equipment refers to the curve used to achieve color matching when the first printing equipment is used as the target for color matching. This is done by adjusting the linearization curve of the second printing equipment. The adjusted linearization curve of the second printing equipment is the preset color matching curve. This color matching curve method is called the linear color matching method. The method for obtaining the preset color matching curve will be described in detail in Example 2 below.

[0066] After obtaining the preset color matching curve, the preset raster image processing device (RIP software installed in the host computer) is controlled to perform image processing on the first image to be printed according to the preset color matching curve. The first image is a bitmap image. In the prior art, the bitmap image to be printed is often sent to the host computer of the printing equipment. The raster image processing device installed in the host computer converts the bitmap image to be printed into raster dot matrix data (image) that the printing equipment can recognize, such as an image in PRN format, according to the linearization curve constructed in the device. The printing equipment controls the ink output of each color channel to print the image according to this raster dot matrix data.

[0067] The preset raster image processing device here can rasterize a bitmap to obtain a raster bitmap image, and can also convert the raster bitmap image into a bitmap image. A preset color-tracking curve is used as the linearization curve in the preset raster image processing device to rasterize the first image, obtaining the raster bitmap data of the first image, denoted as the preset raster bitmap image. Rasterizing the first bitmap image is existing technology and will not be elaborated here. After obtaining the preset raster bitmap image, it is converted into a bitmap image, denoted as the second image. The second image is a bitmap image that has undergone color-tracking processing of the first image using the preset color-tracking curve. The first image and the second image are rasterized again using the first raster image processing device to obtain raster dot matrix data of the first image and the second image, respectively, denoted as the first raster dot matrix image and the second raster dot matrix image. The first raster image processing device here differs from the preset raster image processing device; it is installed in a host computer, performs rasterization on the input bitmap, and then outputs raster dot matrix data (images). The first and second raster dot matrix images are images (data) recognizable by the printing equipment. The first and second raster dot matrix images are sent to the first and second printing devices respectively for printing, outputting a first printed image and a second printed image with consistent colors.

[0068] Current linear color matching methods generally use the linearization curve of a first printing device as the color matching target. Color matching is achieved by adjusting the linearization curve of a second printing device. In this case, the machine state of the second printing device (such as the ink output of each channel) changes with the adjustment of its internal linearization curve, thereby altering the printed output color to match the output color of the first printing device. In this embodiment of the invention, it is not necessary to change the machine state of the second printing device. Instead, the color matching process is placed before the image rasterization process. This is equivalent to adding a preset raster image processing device in front of the raster image processing device of the host computer. The color matching process is completed in this preset raster image processing device, resulting in a color-matched image (bitmap). This image is then sent to the color matching device (second printing device) for normal rasterization processing before printing, thus achieving the color matching objective.

[0069] Because the color matching process is transformed into a front-end file processing step, without requiring changes to the machine state of the printing equipment, it eliminates geographical limitations and enables remote multi-device color matching or color consistency processing. For example, an image to be printed on the local printing equipment, after undergoing color matching processing, is sent to a remote printing equipment for printing, and the printed output image has the same color as the image output from the local printing equipment.

[0070] Example 2

[0071] Based on the above embodiment one, this embodiment of the invention provides a color matching method based on multiple printing devices, the method comprising the following steps:

[0072] Construct multiple preset color matching curves for the second printing equipment relative to the first printing equipment;

[0073] A preset raster image processing device is controlled to process a first image according to the preset color tracking curve to obtain a plurality of second images, wherein the first image and the plurality of second images are bitmaps;

[0074] The first raster image processing device is controlled to perform rasterization processing on the first image and a plurality of second images respectively to obtain a first raster dot matrix image and a plurality of second raster dot matrix images;

[0075] The first raster dot matrix image is sent to the first printing device, and multiple second raster dot matrix images are sent to the corresponding second printing devices for printing.

[0076] The specific implementation of this color matching method based on multiple printing devices is similar to that of Embodiment 1 described above, and will not be repeated here. Using this method, multiple printing devices in the same region can simultaneously output images with consistent colors, enabling mass production of color-consistent images and greatly improving production efficiency. Furthermore, this method can also ensure that various image output devices in different regions output images with consistent colors, thereby overcoming geographical limitations and achieving color consistency across multiple types of image output devices remotely. For example, this method can ensure that images printed by printing devices in locations A, B, and C have consistent colors, enabling remote sample color confirmation.

[0077] Example 3

[0078] Based on the above embodiment one, embodiment two of the present invention discloses a method for obtaining a preset color-tracking curve. Specifically, the method includes:

[0079] S11: Control the first printing equipment to print a preset color block image to obtain a first color block image; wherein, the preset color block image includes several color blocks with different ink amounts;

[0080] S12: Control the second printing equipment to print the preset color block image to obtain the second color block image;

[0081] S13: Obtain the ink volume of the second printing device based on the first color block image and the second color block image;

[0082] S14: Control the second printing equipment to reprint the preset color block image according to the ink cut-off amount to obtain the third color block image;

[0083] S15: Obtain the preset color matching curve based on the first color block image and the third color block image.

[0084] Specifically, the preset color block diagram here includes several color blocks with different ink amounts. For example, such as... Figure 2 As shown, the preset color block diagram includes 21 color blocks with different ink volumes, arranged in ascending order of ink volume, with a minimum ink output of 0 and a maximum of 100. Therefore, the ink volume interval between each color block in the preset color block diagram is 5, and the ink output of each color block is 0, 5, 10, 15, ..., 100 respectively. It is worth noting that the number of color blocks and the ink volume settings for each color block in the preset color block diagram can be adjusted according to actual conditions. For example, if the preset color block diagram includes 11 color blocks with different ink volumes, arranged in ascending order of ink volume, with a minimum ink output of 0 and a maximum of 100, then the ink volume interval between each color block in the preset color block diagram is 10, and the ink output of each color block is 0, 10, 20, ..., 100 respectively.

[0085] After obtaining the preset color block image, the first printing equipment and the second printing equipment are controlled to print the preset color block image to obtain the first color block image and the second color block image, respectively. Figure 3a and Figure 3b As shown, the first color block diagram and the second color block diagram respectively reflect the actual ink output state of the first printing equipment and the second printing equipment under the set ink output volume. Based on the ink output state reflected by the first color block diagram and the second color block diagram, the corresponding color tracking curve of the second printing equipment when the first printing equipment is the color tracking target is constructed, which is the preset color tracking curve.

[0086] When constructing the linearization curve of printing equipment, it is often necessary to first perform ink cut-off processing, that is, to obtain the ink cut-off amount (or ink cut-off data) of the printing equipment.

[0087] Preferably, obtaining the ink volume of the second printing device based on the first color block image and the second color block image includes:

[0088] S131: Obtain the color value of the color block with the largest ink volume in the first color block image, and record it as the first maximum color value;

[0089] S132: Obtain the color block in the second color block image that has the smallest color difference value compared with the first maximum color value, and record it as the ink cut-off color block;

[0090] S133: Obtain the amount of ink in the cut-off ink block, which is the amount of ink cut off.

[0091] Specifically, firstly, the color values ​​of the color blocks in the first color block image are collected. For example, the actual Lab or CMYK values ​​of the color blocks in the first color block image are measured using a photometer. The Lab or CMYK value of the color block with the largest ink volume is obtained and recorded as the first maximum color value. Simultaneously, the color values ​​of each color block in the second color block are obtained. The color values ​​of each color block in the second color block are compared one by one with the first maximum color value. The color block with the smallest color difference value compared to the first maximum color value is found, and the ink volume corresponding to this color block is recorded as the ink volume cut off by the second printing equipment. By comparing the color values ​​of the color blocks in the first and second color block images (the color value comparison can be done manually or automatically using machine vision technology, etc.), the ink volume cut off by the second printing equipment can be obtained simply and quickly.

[0092] After obtaining the ink cutoff amount of the second printing device, the ink cutoff amount is set to the actual maximum output ink volume of the second printing device. Then, according to the control, the second printing device prints a preset color block image based on the original linearization curve to obtain a third color block image. Similarly, the third color block image consists of several color blocks with different ink volumes. For example, as shown in the figure, the ink cutoff amount Cmax is set to 88. Figure 4The third color block diagram shown consists of 21 color blocks. In the third color block diagram, the actual ink volume of each color block is 0, 4, 8, ..., 88, respectively. After obtaining the third color block diagram, the actual color value of each color block in the third color block diagram is collected. In one example, a photometer is used to obtain the actual Lab or CMYK value of each color block in the third color block diagram.

[0093] After obtaining the actual maximum ink output (cut-off ink volume) of the second printing device and printing the third color block image based on the cut-off ink volume, the preset color tracking curve is obtained based on the color difference of the color blocks at the same position in the first color block image and the third color block image.

[0094] Preferably, obtaining the preset color matching curve based on the first color block image and the third color block image includes:

[0095] S151: Obtain the color difference value between each color block in the third color block image and the color block with the smallest ink amount in the first color block image, and obtain the ink amount of each color block in the third color block image and its corresponding color difference value, which is denoted as the first color difference set;

[0096] S152: Obtain the color difference value between each color block in the first color block image and the color block with the smallest ink amount in the first color block image, and obtain the set of ink amount of each color block in the first color block image and its corresponding color difference value, which is denoted as the second color difference set;

[0097] S153: Obtain the preset color matching curve based on the first color difference set and the second color difference set.

[0098] Preferably, obtaining the preset color matching curve based on the first color difference set and the second color difference set includes:

[0099] S1531: Fit the elements in the first color difference set to obtain the first fitting curve;

[0100] S1532: Obtain the ink amount of the color block in all elements of the second color difference set, and record it as the first ink amount;

[0101] S1533: Obtain the second ink amount corresponding to the color difference value in all elements of the second color difference set according to the first fitting curve;

[0102] S1534: Fit the first ink volume and the second ink volume to obtain the preset color matching curve.

[0103] Specifically, let the number of color blocks in both the third and first color block diagrams be n. Calculate the color difference between each color block in the third color block diagram and the color block with the smallest ink content in the first color block diagram, and obtain the first color difference set A, A = {(C A1 ΔE A1 ),(CA2 ΔE A2 ),……,(C An ΔE An )}, where ΔE A1 C is the color difference between the first color patch in the third color patch image and the color patch with the smallest ink content in the first color patch image. A1 ΔE represents the ink volume corresponding to the first color block in the third color block image. A2 C represents the color difference between the second color patch in the third color patch image and the color patch with the smallest ink content in the first color patch image. A2 For the ink volume corresponding to the second color block in the third color block image, and so on, ΔE An C represents the color difference between the second color patch in the third color patch image and the color patch with the smallest ink content in the first color patch image. An is the amount of ink corresponding to the first color block in the third color block image, and n is the number of color blocks in the third color block image.

[0104] Similarly, calculate the color difference between each color patch in the first color patch image and the color patch with the smallest ink content in the first color patch image to obtain the second color difference set B, B = {(C B1 ΔE B1 ),(C B2 ΔE B2 ),……,(C Bn ΔE Bn )}, where ΔE B1 C is the color difference between the first color patch in the first color patch image and the color patch with the smallest ink content in the first color patch image. B1 ΔE represents the ink volume corresponding to the first color block in the first color block image. B2 C is the color difference between the second color patch in the first color patch image and the color patch with the smallest ink content in the first color patch image. B2 For the ink volume corresponding to the second color block in the first color block image, and so on, ΔE Bn C is the color difference between the nth color patch in the first color patch image and the color patch with the smallest ink content in the first color patch image. Bn Let C be the ink amount corresponding to the nth color block in the first color block image, where n is the number of color blocks in the third color block image. Then, let C be the ink amount of each element in the second color difference set. B1 C B2 ... C Bn Collectively referred to as the first ink volume.

[0105] Each element (C) in the first color difference set A1 ΔE A1 ),(C A2 ΔE A2 ),……,(C An ΔE AnThe first color difference set A is represented by n coordinate points on a two-dimensional plane, with ink volume as the x-axis and color difference as the y-axis. A cubic spline curve is fitted to all elements in the first color difference set A to obtain the first fitted curve.

[0106] The second ink volume corresponding to the color difference value in all elements of the second color difference set is obtained based on the first fitted curve; the color difference value ΔE of all elements in the second color difference set is... B1 ΔE B2 ... ΔE Bn Substituting into the first fitted curve, we obtain the second ink amount corresponding to each of the above color difference values: C B1 '、C B2 '、……、C Bn ', for (C) B1 C B1 '), (C B2 C B2 '), ..., (C Bn C Bn The fitting process is performed, and the resulting fitted curve is the preset color matching curve for the second printing equipment. For example, such as... Figure 5 The figure shown is for (C) B1 C B1 '), (C B2 C B2 '), ..., (C Bn C Bn The preset color matching curve for the second printing equipment is obtained by fitting the data at each point. Based on this fitting method, the preset color matching curve exhibits small color difference, high color reproduction, and good color matching effect. Controlling the second printing equipment to dispense ink according to this preset color matching curve ensures that the output color matches that of the first printing equipment. Because this color matching curve is obtained from the linearized curve of the printing equipment, the method of color matching using this curve is also called the linear color matching method.

[0107] In other embodiments, the method for obtaining the preset color tracking curve can be based on the color tracking curve acquisition method described in the patent application "Color Reproduction Method, Apparatus and Device for Inkjet Printer" (application date: November 12, 2021, application number: 202111341290.2) or the patent application "Iterative Color Tracking Method, Apparatus and Device for Inkjet Printer" (application date: November 12, 2021, application number: 202111341286.6) (application date: November 12, 2021).

[0108] In this embodiment of the invention, after obtaining the preset color matching curve, instead of using the conventional linear color matching method to control the second printing equipment to adjust the output ink volume according to the preset color matching curve, the color matching process is placed before the image is rasterized. This is equivalent to adding a preset raster image processing device in front of the raster image processing device of the host computer. The color matching process is completed in the preset raster image processing device, resulting in a color-matched image (bitmap). After the image is sent to the color matching device (second printing equipment) for normal rasterization processing, printing is performed to achieve the purpose of color matching.

[0109] Example 4

[0110] Please see Figure 6 This invention provides a color matching device 200 for printing equipment, the device 200 comprising:

[0111] The preset color matching curve construction module 201 is used to construct a preset color matching curve of the second printing equipment relative to the first printing equipment;

[0112] Image processing module 202 is used to control a preset raster image processing device to process the first image according to the preset color tracking curve to obtain a second image, wherein both the first image and the second image are bitmaps;

[0113] Raster processing module 203 is used to control the first raster image processing device to perform rasterization processing on the first image and the second image respectively to obtain the first raster dot matrix image and the second raster dot matrix image;

[0114] The printing module 204 is used to send the first raster dot matrix image and the second raster dot matrix image to the first printing equipment and the second printing equipment respectively for printing.

[0115] In summary, the color matching device for printing equipment provided in this embodiment of the invention processes a first image to be printed according to a preset color matching curve using a preset raster image device to obtain a second image. Then, the first and second images are rasterized and sent to the corresponding first and second printing devices for printing, resulting in a printed image with consistent color. This method is equivalent to adding a preset raster image processing device in front of the raster image processing device on the host computer, completing the color matching process within this preset raster image processing device. After obtaining the second image with completed color matching, it is sent to the second printing device (which acts as the color matching device) for normal rasterization before printing, thus achieving color consistency with the output color of the first image printed by the first printing device. This invention avoids repeatedly adjusting the color management curve of the second printing device for color matching, completing color matching without changing the equipment status, greatly reducing the operator's threshold and saving enterprise costs.

[0116] Example 5

[0117] In addition, the color matching method for printing equipment in this embodiment of the invention can be implemented by a color matching device for printing equipment. Figure 7 A schematic diagram of the hardware structure of the color matching device for printing equipment provided in an embodiment of the present invention is shown.

[0118] The color matching device for printing equipment may include a processor 301 and a memory 302 storing computer program instructions.

[0119] 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.

[0120] Memory 302 may include mass storage for data or instructions. For example, and not limitingly, memory 302 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or 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.

[0121] The processor 301 reads and executes computer program instructions stored in the memory 302 to implement any of the color matching methods for printing equipment in the above embodiments.

[0122] In one example, the color-matching device for printing equipment may also include a communication interface 303 and a bus 310. For example, Figure 7 As shown, the processor 301, memory 302, and communication interface 303 are connected through bus 310 and complete communication with each other.

[0123] 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.

[0124] Bus 310 includes hardware, software, or both, that couples components of a printing apparatus color matching device together. For example, and not as a limitation, 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.

[0125] Example 6

[0126] Furthermore, in conjunction with the color matching method for printing equipment 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 these computer program instructions are executed by the processor 301, they implement any of the color matching methods for printing equipment in the above embodiments.

[0127] 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. 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.

[0128] 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.

[0129] 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.

[0130] 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 equipment, characterized in that, The method includes: Constructing a preset color matching curve for a second printing device relative to a first printing device includes: controlling the first printing device to print a preset color block image to obtain a first color block image; wherein, the preset color block image includes several color blocks with different ink amounts; controlling the second printing device to print the preset color block image to obtain a second color block image; obtaining the ink cut-off amount of the second printing device based on the first color block image and the second color block image; controlling the second printing device to reprint the preset color block image based on the ink cut-off amount to obtain a third color block image; and obtaining the preset color matching curve based on the first color block image and the third color block image. Controlling a preset raster image processing device to process a first image according to a preset color-tracking curve to obtain a second image includes: controlling the preset raster image processing device to perform rasterization processing on the first image according to the preset color-tracking curve to obtain a preset raster dot matrix image; converting the preset raster dot matrix image into a bitmap to obtain a second image; wherein, both the first image and the second image are bitmaps; The first raster image processing device is controlled to perform rasterization processing on the first image and the second image respectively to obtain the first raster dot matrix image and the second raster dot matrix image; The first raster dot matrix image and the second raster dot matrix image are sent to the first printing equipment and the second printing equipment, respectively, for printing.

2. The color matching method for printing equipment according to claim 1, characterized in that, The step of obtaining the ink volume of the second printing device based on the first color block image and the second color block image includes: Obtain the color value of the color block with the largest ink volume in the first color block image, and record it as the first maximum color value; The color block with the smallest color difference value compared with the first maximum color value in the second color block image is recorded as the ink cut-off color block; The amount of ink in the cut-off ink patch is the cut-off ink volume.

3. The color matching method for printing equipment according to claim 1, characterized in that, The step of obtaining the preset color matching curve based on the first color block image and the third color block image includes: Obtain the color difference value between each color block in the third color block image and the color block with the smallest ink amount in the first color block image, and obtain the ink amount of each color block in the third color block image and its corresponding color difference value, which is denoted as the first color difference set; Obtain the color difference value between each color block in the first color block image and the color block with the smallest ink amount in the first color block image, and obtain the set of ink amount of each color block in the first color block image and its corresponding color difference value, which is denoted as the second color difference set; The preset color matching curve is obtained based on the first color difference set and the second color difference set.

4. The color matching method for printing equipment according to claim 3, characterized in that, The step of obtaining the preset color matching curve based on the first color difference set and the second color difference set includes: The elements in the first color difference set are fitted to obtain the first fitting curve; Obtain the ink volume of the color blocks in all elements of the second color difference set, and denote it as the first ink volume; Based on the first fitted curve, obtain the second ink volume corresponding to the color difference value of all elements in the second color difference set; The first ink volume and the second ink volume are fitted to obtain the preset color matching curve.

5. The color matching method for printing equipment according to any one of claims 1-4, characterized in that, The first printing equipment and the second printing equipment are any one of inkjet digital printing equipment, offset printing equipment, gravure printing equipment, letterpress printing equipment, and screen printing equipment.

6. A color matching device for printing equipment, characterized in that, The device includes: A preset color matching curve construction module is used to construct a preset color matching curve of a second printing device relative to a first printing device, including: controlling the first printing device to print a preset color block image to obtain a first color block image; wherein, the preset color block image includes several color blocks with different ink amounts; controlling the second printing device to print the preset color block image to obtain a second color block image; obtaining the ink cut-off amount of the second printing device based on the first color block image and the second color block image; controlling the second printing device to reprint the preset color block image based on the ink cut-off amount to obtain a third color block image; and obtaining the preset color matching curve based on the first color block image and the third color block image. An image processing module is used to control a preset raster image processing device to process a first image according to the preset color tracking curve to obtain a second image, including: controlling the preset raster image processing device to perform rasterization processing on the first image according to the preset color tracking curve to obtain a preset raster bitmap image; converting the preset raster bitmap image into a bitmap to obtain the second image; wherein, both the first image and the second image are bitmaps; The raster processing module is used to control the first raster image processing device to perform rasterization processing on the first image and the second image respectively to obtain the first raster dot matrix image and the second raster dot matrix image; The printing module is used to send the first raster dot matrix image and the second raster dot matrix image to the first printing equipment and the second printing equipment, respectively, for printing.

7. A color matching device for printing equipment, 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 1-5.

8. 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 1-5 is implemented.

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