Printed output color correction method, apparatus, device, and storage medium

Abstract

The application discloses a printing output color correction method, device and equipment and a storage medium, and relates to the technical field of printing. The method compresses the maximum color gamut of a printing device to a reasonable range according to a target ink cutting amount of the printing device, and then a first color management curve based on the compressed color gamut is made and the first color density of each ink amount step is obtained, so that color correction can be conveniently performed when output color difference occurs due to aging of parts and other reasons of the printing device. The method corrects the output color of the printing device to be consistent with the original output color without replacing the aging parts or replacing the ink with higher concentration, ensures the stability of the color output of the printing device, is low in cost, and is convenient to operate.

Description

Technical Field

[0001] This invention relates to the field of printing technology, and in particular to a method, apparatus, device, and storage medium for correcting printed output colors. Background Technology

[0002] In the color management process of printing equipment, color management curves (such as ICC curves) are often created to control the ink output of each channel of the printing equipment, thereby controlling the overall printing color effect. However, over time, due to the aging or wear of machine parts such as printheads, the condition of the printing equipment changes, and the color gamut of the printing equipment gradually shrinks, leading to changes in the output color and affecting the image printing effect. Existing solutions often involve replacing aging printheads or other parts to restore the equipment to its original state, or replacing the ink with a higher concentration to expand the color gamut and then adjusting the color to maintain consistency with the original output color. However, these solutions, such as replacing printheads or using higher concentration inks, are costly, complex to operate, and do not achieve ideal results in maintaining color stability. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a method, apparatus, device and storage medium for correcting the output color of printing equipment, in order to solve the problems of high cost, complicated operation and poor effect in correcting the output color of printing equipment in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a method for correcting printed output colors, the method comprising:

[0005] Obtain the target ink cut-off volume of the printing equipment;

[0006] The first color management curve of the printing equipment is obtained based on the target ink cut-off amount;

[0007] A second linear test pattern is obtained by printing a first linear test pattern based on the first color management curve, wherein the first linear test pattern includes several color blocks with ink volume increasing or decreasing successively;

[0008] Obtain the color density of each color block in the second linear test graph, and denote it as the first color density;

[0009] The output color of the printing equipment is corrected based on the first color density.

[0010] Preferably, the target ink cutoff amount of the printing equipment includes:

[0011] Obtain the standard color management curve of the printing equipment;

[0012] The printing equipment is controlled to print a first ink cut test pattern according to the standard color management curve to obtain a second ink cut test pattern, wherein the first ink cut test pattern includes several color blocks with ink volume increasing or decreasing successively;

[0013] The target ink cut-off amount is obtained based on the second ink cut-off test chart.

[0014] Preferably, obtaining the target ink-cutting amount based on the second ink-cutting test chart includes:

[0015] The actual ink-cutting volume is obtained based on the second ink-cutting test chart;

[0016] The target ink cut-off amount is obtained by subtracting the preset ink cut-off amount from the actual ink cut-off amount.

[0017] Preferably, obtaining the target ink-cutting amount based on the second ink-cutting test chart includes:

[0018] Obtain the color block corresponding to the actual amount of ink cut in the second ink cut test chart, and record it as the first color block;

[0019] Obtain the color value of the first color block and record it as the first color value;

[0020] The color block with a smaller amount of ink adjacent to the first color block is designated as the second color block, and the color value of the second color block is obtained and recorded as the second color value;

[0021] If the color difference between the first color value and the second color value is greater than a preset color difference threshold, then the target ink cut-off amount is equal to the average of the sum of the ink amounts of the first color block and the second color block;

[0022] If the color difference between the first color value and the second color value is less than or equal to the preset color difference threshold, then the target ink cut-off amount is equal to the ink amount of the second color block.

[0023] Preferably, adjusting the output color of the printing equipment according to the first color density includes:

[0024] The first linear test pattern is reprinted to obtain the third linear test pattern;

[0025] Obtain the color density of each color block in the third linear test graph, and denot it as the second color density;

[0026] Replace the second color density with the first color density and recreate the second color management curve of the printing equipment;

[0027] The output color of the printing equipment is corrected based on the second color management curve.

[0028] Preferably, the method further includes:

[0029] The printing equipment is controlled according to the second color management curve to print the first linear test pattern to obtain the fourth linear test pattern;

[0030] The third color density is obtained by obtaining the color density of each color block in the fourth linear test graph;

[0031] The density difference is obtained by comparing the density of the third color with the density of the first color;

[0032] When the density difference is greater than or equal to a preset density threshold, the second color management curve is readjusted according to the first color density until the density difference is less than or equal to the preset density threshold.

[0033] Preferably, the printing equipment includes any one of inkjet digital printing equipment, offset printing equipment, gravure printing equipment, letterpress printing equipment, and screen printing equipment.

[0034] Secondly, embodiments of the present invention provide an image sample reproduction method, the method comprising:

[0035] Acquire image samples;

[0036] Print the image sample according to the method described in the first aspect, and obtain a reproduction image with the same color as the image sample.

[0037] Thirdly, embodiments of the present invention provide a printing output color correction device, the device comprising:

[0038] The target ink cut-off volume acquisition module is used to acquire the target ink cut-off volume of the printing equipment.

[0039] The first color management curve acquisition module is used to acquire the first color management curve of the printing equipment based on the target ink cut-off amount.

[0040] The printing module is used to print a first linear test pattern according to the first color management curve to obtain a second linear test pattern, wherein the first linear test pattern includes a number of color blocks with ink volume increasing or decreasing successively.

[0041] The first color density acquisition module is used to acquire the color density of each color block in the second linear test graph, which is denoted as the first color density.

[0042] The correction module is used to correct the output color of the printing equipment according to the first color density.

[0043] Fourthly, embodiments of the present invention provide a printing apparatus, including: 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 of the first aspect described above.

[0044] Fifthly, embodiments of the present invention provide a storage medium storing computer program instructions thereon, which, when executed by a processor, implement the method of the first aspect described above.

[0045] In summary, the beneficial effects of the present invention are as follows:

[0046] The printing output color correction method, apparatus, device, and storage medium provided in this invention compress the maximum color gamut of the printing equipment to a reasonable range based on the target ink capacity of the printing equipment. Then, a first color management curve based on the compressed color gamut and the first color density of each ink volume tone are obtained to facilitate subsequent color correction when output colors differ due to aging of components or other reasons. This method corrects the output color of the printing equipment to match the original without replacing aging components or using ink with a higher concentration, ensuring the stability of the printing equipment's color output. It is low-cost and easy to operate. Attached Figure Description

[0047] 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.

[0048] Figure 1 This is a schematic flowchart of the printing output color correction method according to an embodiment of the present invention.

[0049] Figure 2 This is a schematic diagram of the first ink-cutting test diagram according to an embodiment of the present invention.

[0050] Figure 3 This is a schematic diagram of the first linear test graph according to an embodiment of the present invention.

[0051] Figure 4 This is a schematic diagram of the color density replacement interface according to an embodiment of the present invention.

[0052] Figure 5 This is a schematic diagram of the printing output color correction device according to an embodiment of the present invention.

[0053] Figure 6 This is a schematic diagram of the printing equipment according to an embodiment of the present invention. Detailed Implementation

[0054] 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.

[0055] 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.

[0056] Example 1

[0057] This invention provides a method for correcting printed output colors. This method is applicable to printing equipment, including digital printing equipment (such as reciprocating scanning inkjet printing equipment, OnePass inkjet printing equipment, high-speed SinglePass inkjet printing equipment, etc.), offset printing equipment, gravure printing equipment, letterpress printing equipment, screen printing equipment, etc. The digital printing equipment includes CMYK four-color channels and may also include several spot color channels. The offset printing equipment, gravure printing equipment, letterpress printing equipment, and screen printing equipment all include CMYK four-color channels.

[0058] Please see Figure 1 The printing output color correction method specifically includes the following steps:

[0059] S1: Obtain the target ink cut-off volume of the printing equipment;

[0060] S2: Obtain the first color management curve of the printing equipment based on the target ink cut-off amount;

[0061] S3: Print the first linear test pattern according to the first color management curve to obtain the second linear test pattern, wherein the first linear test pattern includes several color blocks with ink volume increasing or decreasing successively;

[0062] S4: Obtain the color density of each color block in the second linear test graph, and record it as the first color density;

[0063] S5: Correct the output color of the printing equipment according to the first color density.

[0064] Specifically, the maximum color gamut of a printing device in its current state will continuously shrink over time (due to factors such as aging of machine parts), resulting in inconsistent color output with the original state. To ensure that the output color remains consistent with the initial state after the color gamut (state) changes, a stable color gamut (denoted as the target color gamut) needs to be established for the printing device, serving as a reference for subsequent color adjustments. Therefore, the maximum color gamut of the printing device in its current state can be appropriately compressed, and the color gamut of the printing device after a certain period can be simulated in advance. This compressed color gamut can then be used as the target color gamut for subsequent color adjustments. In this embodiment of the invention, the maximum ink output of the printing device is limited to compress the maximum color gamut to a reasonable range, and this range is used as the target color gamut. The maximum ink output of the printing device within this target color gamut is the target ink cutoff.

[0065] Preferably, the target ink cutoff volume of the printing equipment is obtained through the following steps:

[0066] S11: Obtain the standard color management curve of the printing equipment;

[0067] S12: Control the printing equipment to print a first ink cut test pattern according to the standard color management curve to obtain a second ink cut test pattern, wherein the first ink cut test pattern includes a number of color blocks with ink volume increasing or decreasing successively;

[0068] S13: Obtain the target ink cut-off amount according to the second ink cut-off test chart.

[0069] First, a standard color management curve for the printing equipment is created according to existing conventional procedures (this is prior art and will not be elaborated here). Then, the printing equipment is controlled to print a first ink test pattern according to this standard color management curve. For example, such as... Figure 2 As shown, the first ink test chart includes four color channels: Cyan, Magenta, Yellow, and Black. Each color corresponds to 21 color patches with different ink amounts. These 21 patches are arranged in ascending order of ink amount, with the ink amount for each patch increasing sequentially, for example: 0%, 5%, 10%, 15%, 20%, ..., 100%. In other embodiments, the ink amount for each patch can decrease sequentially, for example: 100%, 90%, ..., 0%. It is worth noting that the color channels, the number of color patches corresponding to each color channel, and the ink amount for each color patch in the first ink test chart can be determined according to actual conditions. Figure 2This is only used as an example to illustrate the first ink-cut test pattern and is not intended to limit the first ink-cut test pattern.

[0070] The first ink cut-off test image is input into the printing equipment. The printing equipment prints the image onto the substrate according to the pre-made standard color management curve. The resulting image is recorded as the second ink cut-off test image. The substrate can be paper, wood, glass, crystal, PVC, ABS, acrylic, metal, plastic, stone, leather, cloth, or other textiles. The second ink cut-off test image provides the actual ink cut-off amount for each color channel on the substrate. For example, if the second ink cut-off test image shows that in a color patch image corresponding to a certain color channel, the color values ​​of the patches after 80% ink volume are very similar or indistinct, then 80% ink volume is the actual ink cut-off amount for that color channel. The actual ink cut-off amounts for different color channels may be the same or different, depending on the substrate material and ink properties.

[0071] The target ink cutoff amount corresponding to the target color gamut should be less than the actual ink cutoff amount. In one embodiment, obtaining the target ink cutoff amount based on the second ink cutoff test chart includes:

[0072] S131: Obtain the actual ink cut-off amount based on the second ink cut-off test chart;

[0073] S132: Subtract the preset ink amount from the actual ink amount to obtain the target ink amount.

[0074] The actual ink cut-off amount in the second ink cut-off test chart can be obtained through human observation or by using a color data acquisition device such as a spectrophotometer to obtain the color values ​​of each color patch. If the color difference between two adjacent color patches is less than or equal to a certain range, the ink amount of the color patch with the smaller ink amount is recorded as the actual ink cut-off amount. After obtaining the actual ink cut-off amount, the target ink cut-off amount is obtained by subtracting the preset ink amount from the actual ink cut-off amount. The preset ink amount can be set according to the actual situation; preferably, the preset ink amount is 2%-5%.

[0075] In another embodiment, obtaining the target ink cutoff amount based on the second ink cutoff test chart includes:

[0076] S133: Obtain the color block corresponding to the actual amount of ink cut off in the second ink cut-off test chart, and record it as the first color block;

[0077] S134: Obtain the color value of the first color block and record it as the first color value;

[0078] S135: The color block with smaller ink volume adjacent to the first color block is recorded as the second color block, and the color value of the second color block is obtained and recorded as the second color value;

[0079] S136: If the color difference between the first color value and the second color value is greater than a preset color difference threshold, then the target ink cut-off amount is equal to the average of the ink amounts of the first color block and the second color block.

[0080] S137: If the color difference between the first color value and the second color value is less than or equal to the preset color difference threshold, then the target ink cut-off amount is equal to the ink amount of the second color block.

[0081] Similarly, the actual ink cut-off amount in the second ink cut-off test chart can be obtained through human observation or by using a color data acquisition device such as a spectrophotometer to obtain the color values ​​of each color block. If the color difference between two adjacent color blocks is less than or equal to a certain range, the ink volume of the color block with the smaller ink volume among these two adjacent color blocks is recorded as the actual ink cut-off amount. The color block corresponding to the actual ink cut-off amount is recorded as the first color block, and the color value of the first color block is recorded as the first color value. In addition, the color block with the smaller ink volume adjacent to the first color block is recorded as the second color block, and the color value of the second color block is obtained and recorded as the second color value. The first color value and the second color value are compared. If the color difference between these two color values ​​is greater than a preset color difference threshold, the average of the ink volumes corresponding to the first color block and the second color block is taken as the target ink cut-off amount. If the color difference is less than or equal to the preset color difference threshold, the ink volume of the second color block with the smaller ink volume is taken as the target ink cut-off value. In other words, when the color difference between the first and second color blocks is significant, the target ink cut-off amount is the midpoint of the ink amount values ​​of the two color blocks; when the color difference between the first and second color blocks is not significant, the target ink cut-off amount is the smaller of the two ink amount values.

[0082] After obtaining the target ink cutoff amount, the printing equipment is processed to cut off the ink based on this target amount, and then the color management curve of the printing equipment is generated according to the conventional process, resulting in the first color management curve. The first color management curve is obtained based on the target ink cutoff amount and is also the first color management curve corresponding to the printing equipment after color gamut compression. The printing equipment is controlled to print a first linear test pattern on the substrate according to the first color management curve to obtain a second linear test pattern. For example, such as... Figure 3 As shown, the first linear test chart includes 22 color blocks with different ink amounts corresponding to four color channels: Cyan, Magenta, Yellow, and Black. These 22 color blocks are arranged in ascending order of ink amount, with the ink amount of each color block increasing sequentially, for example: 0%, 2.5%, 5%, 10%, 15%, 20%, ..., 100%. In other embodiments, the ink amount of each color block can decrease sequentially. It is worth noting that the color channels, the number of color blocks corresponding to each color channel, and the ink output of each color block in the first linear test chart can be determined according to actual conditions. Figure 3This is merely an example to illustrate the first linear test pattern and is not intended to limit the scope of the first linear test pattern. Furthermore, the first linear test pattern may be the same as or different from the first ink-cut test pattern.

[0083] The color density of each color patch in the second linear color patch image is collected using a color data acquisition device such as a spectrophotometer, and recorded as the first color density. The first color density is actually the color density value of each color channel at each ink volume level (i.e., 0%, 2.5%, 5%, 10%, ... 100%) after the color gamut of the printing equipment has been compressed. In one embodiment, a color density table for each ink volume level of each color channel is established and saved. When the color gamut of the printing equipment changes due to aging of machine parts or wear of printheads after a period of time, resulting in inconsistent output color effects, the output color of the printing equipment can be corrected according to the first color density, so as to keep the output color consistent between the early and late stages.

[0084] Specifically, correcting the output color of the printing equipment based on the first color density includes:

[0085] S51: Reprint the first linear test pattern to obtain the third linear test pattern;

[0086] S52: Obtain the color density of each color block in the third linear test graph, and record it as the second color density;

[0087] S53: Replace the second color density with the first color density and recreate the second color management curve of the printing equipment;

[0088] S54: Correct the output color of the printing equipment according to the second color management curve.

[0089] The first linear test pattern is reprinted on the substrate to obtain the third linear test pattern. The color density of each color patch in the third linear color patch pattern is collected using a color data acquisition device such as a spectrophotometer, and recorded as the second color density. The second color density characterizes the output color effect after the printing equipment state changes. To correct the output color, the second color density of each ink volume level in each color channel is replaced with the corresponding first color density, and the color management curve of the printing equipment is recreated, recorded as the second color management curve. In one embodiment, the color density replacement function is integrated into the color management software; during replacement, only the human-computer interaction window needs to display... Figure 4The interface shown displays ink density gradations, such as 0%, 2.5%, 5%, 10%, ... 100%, with "Target C" representing the first color density of channel C, "Measured C" representing the second color density of channel C, "Target M" representing the first color density of channel M, "Measured M" representing the second color density of channel M, and so on. After filling in the first and second color densities for each channel's ink density gradation, the software saves the data. The color management software then generates a second color management curve based on this data. The printing equipment is then controlled to reprint the first linear test chart up to the fourth linear test chart based on the second color management curve. Finally, the color density of each ink density gradation for each color channel obtained from the fourth linear test chart is essentially consistent with the first color density, thus adjusting the printing equipment's output color to match the original and ensuring the stability of the printing equipment's color output.

[0090] In one embodiment, the printing output color correction method further includes:

[0091] S60: Control the printing equipment to print the first linear test pattern according to the second color management curve to obtain the fourth linear test pattern;

[0092] S61: Obtain the color density of each color block in the fourth linear test graph to obtain the third color density;

[0093] S62: Compare the density of the third color with the density of the first color to obtain the density difference;

[0094] S63: When the density difference is greater than or equal to a preset density threshold;

[0095] S64: Re-adjust the second color management curve according to the first color density until the density difference is less than or equal to the preset density threshold.

[0096] Specifically, the printing equipment is controlled to reprint the first linear test image according to the second color management curve, leading to the fourth linear test image. Similarly, a color data acquisition device, such as a spectrophotometer, is used to collect the color density of each color block in the fourth linear color block image, which is recorded as the third color density. The third color density is compared with the first color density to obtain the density difference between the third color density and the first color density. If the density difference is large (e.g., greater than or equal to a preset density threshold), it is considered that the color output effect after this curve adjustment does not meet the requirements. At this time, the third color density of each ink volume level of each color channel is replaced with the corresponding first color density, and a new second color management curve is obtained. Similarly, the printing equipment is controlled to reprint the first linear test image according to the new second color management curve, leading to a new fourth linear test image. The color density of each color block in the new fourth linear color block image is collected to obtain the new third color density. The first color density is compared with the new third color density... The above process is repeated until the difference between the third color density and the first color density of each ink volume level of each color channel obtained according to the fourth linear test image is less than the preset density threshold, thereby ensuring that the color output effect of the printing equipment is consistent.

[0097] In summary, the printing output color correction method provided by this invention compresses the maximum color gamut of the printing equipment to a reasonable range based on the target ink volume of the printing equipment. Then, it generates a first color management curve based on the compressed color gamut and obtains the first color density for each ink volume level to facilitate subsequent color correction when output colors differ due to component aging or other reasons. This method corrects the output color of the printing equipment to match the original without replacing aging components or using ink with a higher concentration, ensuring the stability of the printing equipment's color output. It is low-cost and easy to operate.

[0098] Example 2

[0099] Based on the above embodiment one, embodiment two of the present invention provides an image sample reproduction method, the method comprising:

[0100] Acquire image samples;

[0101] Print the image sample according to the output color correction method described in Example 1 to obtain a reproduction image with the same color as the image sample.

[0102] In practical production applications, it is often necessary to reprint image samples from orders placed a few days or months ago (also known as reorders). This requires printing a batch of images with the same colors as the previous image samples. However, during this period, machine conditions, ink batches, and printhead conditions can change (e.g., changes in the machine's environment, ink batches, or printhead wear due to prolonged use). This can lead to significant color differences between the images printed on the same printing equipment after a certain time interval, even when performing the same printing task. The current practice is that if a printing machine performed a printing task some time ago and then needs to perform a reorder at a specified time, it is necessary to reprint a proof based on the original image sample, and then readjust the colors based on the printed output or perform color matching processing on the printing equipment to ensure consistent printing colors when performing the same printing task before and after the previous period. According to the method in Embodiment 1 of the present invention, it is only necessary to send the image sample (or the electronic artwork of the image sample scanned by a scanner or other device) from several days or months ago to the printing equipment. The printing equipment adjusts the color according to the printing output color correction method described in Embodiment 1 above and outputs an image with the same color as the image sample. This image has the same color as the image produced several days or months ago.

[0103] It's worth noting that if the inconsistent output colors aren't due to changes in the printing equipment's state caused by aging or wear, the existing methods described above will struggle to achieve the original state before the equipment change. In such cases, replacing parts and redoing color matching and proofing would be necessary. By compressing the printing equipment's color gamut, a certain degree of equipment aging or wear can be prevented from affecting the output color quality, reducing parts replacement cycles and maintenance costs.

[0104] Example 3

[0105] Based on the above embodiments one and two, this invention provides a method for output color reproduction based on multiple printing devices, the method comprising:

[0106] Obtain the current color output status of multiple printing devices;

[0107] Compare the color output status of the multiple printing devices recorded before a preset time with the current color output status;

[0108] When the comparison results meet the preset conditions, the output colors of the multiple printing devices are corrected according to the printing output color correction method as described in Example 1.

[0109] In practical production applications, multiple printing machines of the same type are often used to print the same image sample, thereby improving production efficiency. Of course, before production, color matching processing is performed on multiple printing machines to ensure consistent color output. To ensure consistent output color when using these multiple printing machines for repeat production later or after a period of time, it is necessary to record the color output status of these multiple printing machines. For example, this could involve controlling multiple printing machines to print standard color targets to obtain physical color targets, saving the physical targets, or recording the color management curves of these multiple machines. When a repeat order is needed after a few days, months, or a preset time, the first step is to check whether the color output status of the current printing equipment is consistent with that before the preset time. For example, multiple printing equipment are controlled to print the same standard color target to obtain a new physical color target. Then, it is compared with the physical color target printed before the repeat order (before the preset time). If the comparison result meets the preset conditions, the output color of the current printing equipment needs to be corrected. For example, if the color difference value of N color blocks between the physical color target before the repeat order and the new physical color target is greater than or equal to 2.5 or other preset color difference values, it is considered to meet the preset conditions. Alternatively, if the color management curves recorded before and after the repeat order are compared and the curves show a large difference, it is considered that the output color of the current printing equipment needs to be corrected; otherwise, it is impossible to print an image with the same color as before the repeat order. Accordingly, the printing output color correction method described in Embodiment 1 is used to correct the output color of multiple printing equipment to achieve the color output status before the repeat order (or before the preset time). Furthermore, the output colors of the multiple printing equipment after correction are compared. If there are differences in the output colors, these printing equipment are re-processed for color tracking to make their output color consistency higher. Using the method provided in the embodiments of the present invention, multiple printing machines can be used for simultaneous reorder production, which can greatly improve the production efficiency of reorders.

[0110] Example 4

[0111] Please see Figure 5 This invention provides a printing output color correction device 200, the device 200 comprising:

[0112] The target ink cut-off volume acquisition module 201 is used to acquire the target ink cut-off volume of the printing equipment.

[0113] The first color management curve acquisition module 202 is used to acquire the first color management curve of the printing equipment according to the target ink cut-off amount.

[0114] Printing module 203 is used to print a first linear test pattern according to the first color management curve to obtain a second linear test pattern, wherein the first linear test pattern includes a number of color blocks with ink volume increasing or decreasing successively;

[0115] The first color density acquisition module 204 is used to acquire the color density of each color block in the second linear test graph, which is denoted as the first color density.

[0116] The correction module 205 is used to correct the output color of the printing device according to the first color density.

[0117] Preferably, the correction module 205 includes:

[0118] The third linear test pattern acquisition unit is used to reprint the first linear test pattern to obtain the third linear test pattern;

[0119] The second color density acquisition unit is used to acquire the color density of each color block in the third linear test graph, which is denoted as the second color density.

[0120] A replacement unit is used to replace the second color density with the first color density and recreate the second color management curve of the printing equipment;

[0121] The correction unit is used to correct the output color of the printing equipment according to the second color management curve.

[0122] Obtain the standard color management curve of the printing equipment;

[0123] Preferably, the target ink interception volume acquisition module 201 includes:

[0124] The second ink test pattern acquisition unit is used to control the printing equipment to print the first ink test pattern according to the standard color management curve to obtain the second ink test pattern, wherein the first ink test pattern includes a number of color blocks with ink volume increasing or decreasing successively.

[0125] The target ink cut-off amount acquisition unit is used to acquire the target ink cut-off amount based on the second ink cut-off test chart.

[0126] Preferably, the target ink interception volume acquisition unit includes:

[0127] The actual ink-cutting volume acquisition unit is used to acquire the actual ink-cutting volume based on the second ink-cutting test chart.

[0128] The first ink cut-off amount acquisition unit is used to subtract the preset ink amount from the actual ink cut-off amount to obtain the target ink cut-off amount.

[0129] Preferably, the target ink interception volume acquisition unit includes:

[0130] The first color block acquisition unit is used to acquire the color block corresponding to the actual amount of ink cut in the second ink cut test diagram, and denoted as the first color block;

[0131] The first color value acquisition unit is used to acquire the color value of the first color block, which is denoted as the first color value;

[0132] The second color value acquisition unit is used to mark the color block with a smaller amount of ink adjacent to the first color block as the second color block, acquire the color value of the second color block, and record it as the second color value;

[0133] The second ink cut-off amount acquisition unit is used to determine if the color difference between the first color value and the second color value is greater than a preset color difference threshold, in which case the target ink cut-off amount is equal to the average of the sum of the ink amounts of the first color block and the second color block.

[0134] The third ink cut-off quantity acquisition unit is used to determine if the color difference between the first color value and the second color value is less than or equal to the preset color difference threshold, in which case the target ink cut-off quantity is equal to the ink quantity of the second color block.

[0135] Preferably, the printing output color correction device further includes:

[0136] The fourth linear test pattern acquisition module is used to control the printing equipment to print the first linear test pattern according to the second color management curve to obtain the fourth linear test pattern;

[0137] The third color density acquisition module is used to acquire the color density of each color block in the fourth linear test graph to obtain the third color density.

[0138] The density difference acquisition module is used to compare the density of the third color and the density of the first color to obtain the density difference.

[0139] An iterative module is used to readjust the second color management curve according to the first color density until the density difference is less than or equal to the preset density threshold when the density difference is greater than or equal to the preset density threshold.

[0140] In summary, the printing output color correction device provided in this embodiment of the invention compresses the maximum color gamut of the printing equipment to a reasonable range based on the target ink volume of the printing equipment. Then, it generates a first color management curve based on the compressed color gamut and obtains the first color density for each ink volume level to facilitate subsequent color correction when output colors differ due to aging of components or other reasons. This method corrects the output color of the printing equipment to match the original without replacing aging components or using ink with a higher concentration, ensuring the stability of the printing equipment's color output. It is low-cost and easy to operate.

[0141] Example 5

[0142] Furthermore, the printing output color correction method of this invention can be implemented by printing equipment. Figure 6A schematic diagram of the hardware structure of the printing equipment provided in an embodiment of the present invention is shown.

[0143] The printing apparatus may include a processor 301 and a memory 302 storing computer program instructions.

[0144] 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.

[0145] 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.

[0146] The processor 301 reads and executes computer program instructions stored in the memory 302 to implement any of the printing output color correction methods in the above embodiments.

[0147] In one example, the printing apparatus 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.

[0148] 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.

[0149] Bus 310 includes hardware, software, or both, that couples components of a printing apparatus 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. While specific buses are described and illustrated in embodiments of the invention, the invention contemplates any suitable bus or interconnect.

[0150] Example 6

[0151] Furthermore, in conjunction with the printing output color correction 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 these computer program instructions are executed by the processor 301, they implement any of the printing output color correction methods in the above embodiments.

[0152] In summary, the printing output color correction method, apparatus, device, and storage medium provided in this invention compress the maximum color gamut of the printing equipment to a reasonable range based on the target ink cut-off amount. Then, a first color management curve based on the compressed color gamut and the first color density of each ink volume tone are generated to facilitate subsequent color correction when output colors differ due to component aging or other reasons. This method corrects the output color of the printing equipment to match the original without replacing aging components or using ink with higher concentration, ensuring the stability of the printing equipment's color output. It is low-cost and easy to operate.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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 method for correcting colors in printed output, characterized in that, The method includes: Obtaining the target ink cut-off amount of a printing device includes: obtaining a standard color management curve of the printing device; controlling the printing device to print a first ink cut-off test pattern according to the standard color management curve to obtain a second ink cut-off test pattern, wherein the first ink cut-off test pattern includes several color blocks with ink amounts increasing or decreasing sequentially; and obtaining the target ink cut-off amount based on the second ink cut-off test pattern. The first color management curve of the printing equipment is obtained based on the target ink cut-off amount; A second linear test pattern is obtained by printing a first linear test pattern based on the first color management curve, wherein the first linear test pattern includes several color blocks with ink volume increasing or decreasing successively; Obtain the color density of each color block in the second linear test graph, and denote it as the first color density; Correcting the output color of the printing equipment based on the first color density includes: reprinting the first linear test pattern to obtain a third linear test pattern; obtaining the color density of each color block in the third linear test pattern, denoted as the second color density; replacing the second color density with the first color density and recreating the second color management curve of the printing equipment; and correcting the output color of the printing equipment based on the second color management curve. The step of obtaining the target ink cut-off amount based on the second ink cut-off test chart includes: The actual ink cut-off amount is obtained according to the second ink cut-off test chart; the target ink cut-off amount is obtained by subtracting the preset ink amount from the actual ink cut-off amount. or, Obtain the color block corresponding to the actual ink cut-off amount in the second ink cut-off test image, and record it as the first color block; obtain the color value of the first color block, and record it as the first color value; record the color block with smaller ink volume adjacent to the first color block as the second color block, and obtain the color value of the second color block, and record it as the second color value; if the color difference between the first color value and the second color value is greater than a preset color difference threshold, then the target ink cut-off amount is equal to the average of the sum of the ink volumes of the first color block and the second color block; if the color difference between the first color value and the second color value is less than or equal to the preset color difference threshold, then the target ink cut-off amount is equal to the ink volume of the second color block.

2. The printing output color correction method according to claim 1, characterized in that, The method further includes: The printing equipment is controlled according to the second color management curve to print the first linear test pattern to obtain the fourth linear test pattern; The third color density is obtained by obtaining the color density of each color block in the fourth linear test graph; The density difference is obtained by comparing the density of the third color with the density of the first color; When the density difference is greater than or equal to a preset density threshold, the second color management curve is readjusted according to the first color density until the density difference is less than or equal to the preset density threshold.

3. The printing output color correction method according to claim 1 or 2, characterized in that, The printing equipment includes any one of inkjet digital printing equipment, offset printing equipment, gravure printing equipment, letterpress printing equipment, and screen printing equipment.

4. A method for reproducing an image sample, characterized in that, The method includes: Acquire image samples; Print the image sample according to any one of claims 1-3 to obtain a reproduction image with the same color as the image sample.

5. A printing output color correction device, characterized in that, The device includes: A target ink cut-off volume acquisition module is used to acquire the target ink cut-off volume of a printing device, including: acquiring the standard color management curve of the printing device; controlling the printing device to print a first ink cut-off test pattern according to the standard color management curve to obtain a second ink cut-off test pattern, wherein the first ink cut-off test pattern includes several color blocks with progressively increasing or decreasing ink volume; and acquiring the target ink cut-off volume based on the second ink cut-off test pattern, including: The actual ink cut-off amount is obtained according to the second ink cut-off test chart; the target ink cut-off amount is obtained by subtracting the preset ink amount from the actual ink cut-off amount. or, Obtain the color block corresponding to the actual ink cut-off amount in the second ink cut-off test image, and record it as the first color block; obtain the color value of the first color block, and record it as the first color value; record the color block with smaller ink volume adjacent to the first color block as the second color block, and obtain the color value of the second color block, and record it as the second color value; if the color difference between the first color value and the second color value is greater than a preset color difference threshold, then the target ink cut-off amount is equal to the average of the sum of the ink volumes of the first color block and the second color block; if the color difference between the first color value and the second color value is less than or equal to the preset color difference threshold, then the target ink cut-off amount is equal to the ink volume of the second color block; The first color management curve acquisition module is used to acquire the first color management curve of the printing equipment based on the target ink cut-off amount. The printing module is used to print a first linear test pattern according to the first color management curve to obtain a second linear test pattern, wherein the first linear test pattern includes a number of color blocks with ink volume increasing or decreasing successively. The first color density acquisition module is used to acquire the color density of each color block in the second linear test graph, which is denoted as the first color density. The correction module is used to correct the output color of the printing equipment according to the first color density, including: reprinting the first linear test pattern to obtain a third linear test pattern; obtaining the color density of each color block in the third linear test pattern, denoted as the second color density; replacing the second color density with the first color density and recreating the second color management curve of the printing equipment; and correcting the output color of the printing equipment according to the second color management curve.

6. A printing apparatus, 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.

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