Method and device for color register calibration of channels in same nozzle and storage medium

Abstract

The invention discloses a method and equipment for chromatography calibration of channels in the same nozzle and a storage medium. The method comprises the following steps: S1, obtaining a chromatography calibration pattern and importing the chromatography calibration pattern into a printer system; s2, printing a color register calibration pattern; s3, inputting the color register calibration pattern printed in the step S2 into picture processing software; s4, importing the color register calibration pattern in the step S1 into picture processing software; and S5, comparing the color register calibration pattern input in the step S3 with the color register calibration pattern imported in the step S4, and calibrating control parameters of a printer system according to a comparison result. The method solves the problem that in the prior art, errors of up-and-down offset color register between channels in the nozzles cannot be effectively calibrated, and left-and-right and up-and-down color register errors between the nozzles can be calibrated at the same time; in addition, the calibration image can be output at any resolution ratio, so that the printing requirements of different resolution ratios can be met, and the calibration precision and the printing quality of the printer are greatly improved.

Description

Technical Field

[0001] This invention relates to the technical field of printers, and in particular to a method, apparatus, and storage medium for color registration calibration within a single printhead channel. Background Technology

[0002] Conventional printhead internal channel color registration calibration typically consists of a simple calibration element and a reference element composed of thick and thin vertical lines, respectively. The resolution of the calibration image is usually set to the printer's reference resolution. However, during production, the resolution of printed images is often an integer multiple of the printer's reference resolution. Therefore, due to assembly or processing errors, this method can easily lead to inaccurate calibration and fail to calibrate vertical misalignment errors between printhead internal channels.

[0003] Traditional printhead internal channel color registration calibration methods primarily rely on calibration primitives composed of thick and thin vertical lines, and the resolution of the calibration pattern is fixed at the printer's reference resolution. This method has limitations when calibrating high-resolution print jobs, failing to adequately adapt to different resolution requirements, thus limiting calibration accuracy.

[0004] Existing technologies cannot effectively calibrate the vertical offset color registration error between channels within the printhead, and the calibration effect is poor when printing at non-reference resolutions, affecting print quality. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a method, apparatus and storage medium for color matching calibration of channels within the same printhead.

[0006] The technical solution of this invention is implemented as follows:

[0007] A method for color matching calibration within the same printhead channel includes the following steps:

[0008] S1, Obtain the color calibration pattern and import it into the printer system;

[0009] S2, according to step S1, print the color calibration pattern;

[0010] S3, Input the color calibration pattern printed in step S2 into the image processing software;

[0011] S4. Import the color calibration pattern from step S1 into the image processing software.

[0012] S5. Compare the color calibration pattern entered in step S3 with the color calibration pattern imported in step S4, and calibrate the control parameters of the printer system according to the comparison results.

[0013] Preferably, in step S1, the color calibration pattern is specifically a set of patterns composed of multiple large squares, small squares and color blocks in a grid pattern, wherein the color blocks are placed in the middle of the small squares, the small squares are placed in the middle of the large squares, and adjustment parameters of the same size as those in the printer system are set below each set of patterns.

[0014] Preferably, step S3 specifically involves scanning and inputting the color calibration pattern printed in step S2 into image processing software, and adjusting the size of the input color calibration pattern in the image processing software.

[0015] An apparatus for color matching calibration of channels within the same nozzle includes at least one processor, at least one memory, and computer program instructions stored in the memory. When the computer program instructions are executed by the processor, they implement the aforementioned method for obtaining color matching calibration of channels within the same nozzle.

[0016] A storage medium storing computer program instructions that, when executed by a processor, implement the aforementioned method for color matching calibration of channels within the same printhead.

[0017] This invention solves the problem that existing technologies cannot effectively calibrate the vertical misalignment and color registration errors between channels within the printhead. It can simultaneously calibrate the horizontal and vertical misalignment and color registration errors between printheads, thus improving calibration efficiency. In addition, the calibration diagram of this invention can be output at any resolution, thereby adapting to printing needs of different resolutions and greatly improving the calibration accuracy and print quality of the printer. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a method for color matching calibration within the same nozzle channel according to the present invention.

[0019] Figure 2 This is a schematic diagram of a color calibration pattern for a method of color calibration within the same nozzle channel according to the present invention. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, exemplary embodiments will be described in detail below, examples of which are illustrated in the accompanying drawings. In the following description relating to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of methods and systems consistent with some aspects of this application as detailed in the appended claims.

[0021] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0022] Example 1

[0023] like Figure 1 and Figure 2 As shown, the present invention provides a method for color matching calibration within a single printhead channel, comprising the following steps:

[0024] S1, Obtain the color calibration pattern and import it into the printer system;

[0025] Preferably, in step S1, the color calibration pattern is specifically a set of patterns composed of multiple large squares, small squares, and color blocks in a grid format. The color blocks are placed in the center of the small squares, and the small squares are placed in the center of the large squares. Each set of patterns has adjustment parameters of the same size as those in the printer system below it. The four lines of the large squares can be adjusted to different line thicknesses for more intuitive calibration in the horizontal and vertical directions. The color blocks are selected from high-contrast colors such as cyan, magenta, yellow, or black, with a side length of about 1-2 mm. They are placed in the center of the small squares and are completely filled within the small squares in the original calibration pattern for easy comparison later.

[0026] S2, according to step S1, print the color calibration pattern;

[0027] Preferably, in step S2, before printing, a print preview image is captured to determine the specific position of the color calibration pattern on the printing paper. Specifically, with the center of the printing paper as the center point, the coordinate parameters of the four corners of the color calibration pattern are obtained. After capturing the print preview image before printing, in addition to obtaining the coordinate parameters of the four corners of the color calibration pattern, the color distribution histogram of the preview image is also analyzed simultaneously to predict areas where color deviation may occur in advance, providing a reference for the focus of subsequent calibration. At the same time, the coordinate parameters are mapped and correlated with the physical position of the printer head to help determine the potential deviation of the print head when it moves laterally and longitudinally on the paper.

[0028] Before starting printing, use the printer's built-in preview function or professional print management software to capture a print preview image with a resolution of at least 300 dpi. Using the geometric center of the printing paper as the origin, employ a high-precision image analysis algorithm to obtain the coordinate parameters of the four corners of the color calibration pattern, controlling the error within ±0.05 mm. Simultaneously, use a color analysis plugin to analyze the color distribution histogram of the preview image, observing the peak values ​​and distribution of each color channel to estimate areas of color deviation. Furthermore, precisely map the coordinate parameters to the physical layout of the printer head, linking printhead movement. Finally, select the appropriate paper and ink to begin printing.

[0029] S3, Input the color calibration pattern printed in step S2 into the image processing software;

[0030] Preferably, step S3 specifically involves scanning and inputting the color calibration pattern printed in step S2 into image processing software, and adjusting the size of the input color calibration pattern in the image processing software.

[0031] Preferably, step S3 specifically involves scanning and inputting the color calibration pattern printed in step S2 into image processing software, and adjusting the size of the input color calibration pattern in the image processing software.

[0032] Using a scanning device with a resolution of at least 600 dpi, the printed pattern is completely imported into professional image processing software such as Adobe Photoshop or CorelDRAW. An intelligent edge detection tool captures the edge information of the imported pattern, and then obtains paper edge parameters from the paper specifications or printer driver, accurate to 0.01 mm. The imported pattern edges are scaled proportionally accordingly. The software displays the scaling ratio in real time, automatically records the adjustment values, and repeats the process until the difference between the imported pattern and the paper edge parameters is less than 0.01 mm. High scanning accuracy preserves original details, intelligent detection precisely locates edges, and scaling according to the actual paper parameters corrects dimensional deviations caused by scanning and paper deformation. Recorded values ​​facilitate problem remediation.

[0033] S4. Import the color calibration pattern from step S1 into the image processing software.

[0034] S5. Compare the color calibration pattern entered in step S3 with the color calibration pattern imported in step S4, and calibrate the control parameters of the printer system according to the comparison results.

[0035] Preferably, in step S1, the color calibration pattern, in addition to multiple sets of patterns composed of grid-like large and small squares and color blocks, uses contrasting colors commonly found in the printing color gamut, such as cyan, magenta, yellow, and black, to enhance visual recognizability. Simultaneously, a small blank area is reserved around each set of patterns to prevent color interference from affecting subsequent image recognition. The adjustment parameters set below the pattern not only include size information but also additionally indicate the corresponding printhead channel number, facilitating quick location of problematic channels.

[0036] Preferably, the step of adjusting the size of the entered color calibration pattern in the image processing software includes the following steps:

[0037] L1, obtain the edge information of the entered color calibration pattern;

[0038] L2, obtain the edge parameters of the printing paper;

[0039] L3, adjust the edge parameters of the entered color calibration pattern proportionally to the edge parameters of the printing paper;

[0040] L4. Repeat steps L1-L3 until the edge parameters of the entered color calibration pattern are exactly the same as the edge parameters of the printed paper.

[0041] Preferably, step S5, in the image processing software, involves the following steps:

[0042] Q1. Adjust the opacity of the color calibration pattern imported in step S4 to 50-70%. In the image processing software, select the imported original color calibration pattern layer, and through the layer properties panel, drag the opacity slider or directly enter a value to precisely adjust the opacity to the 50-70% range. After multiple tests, 50% opacity clearly shows the underlying pattern, while 70% ensures visual contrast while highlighting the details of the underlying layer, facilitating subsequent operations.

[0043] Q2, place the color calibration pattern obtained in step Q1 at the position in the print preview in step S2. Using the move tool of the image processing software, according to the coordinate parameters obtained in step S2, accurately place the original color calibration pattern with adjusted transparency at the corresponding position in the print preview to ensure that the two are initially aligned in space.

[0044] Q3. Place the color calibration pattern obtained in step S3 at the print preview position in step S2. Similarly, use the move tool to move the entered actual print pattern to the same print preview position as the original pattern in the previous step, in preparation for difference comparison.

[0045] Q4. Using image recognition methods, the two patterns from steps Q2 and Q3 are identified and compared. A deep learning-based image recognition method is employed to train a recognition model specifically tailored to the features of this color calibration pattern. Compared to traditional algorithms, the accuracy in recognizing subtle pattern shifts and color deviations is improved by over 30%. During the identification and comparison process, a comparison heatmap is generated in real time, visually displaying the distribution of differences between the two patterns.

[0046] Q5. Output comparison results. When comparing the entered color calibration pattern with the imported color calibration pattern, in addition to using the difference in coordinate parameters before and after the movement as the benchmark for adjusting the control parameters of the printer system, the software system also comprehensively considers the color deviation value when the color blocks fill the small squares. The software system organizes the comparison data, accurately calculates the difference in coordinate displacement of the entered pattern relative to the original pattern in the horizontal and vertical directions, and quantifies the color deviation when the color blocks fill the small squares, forming a detailed comparison report.

[0047] Preferably, the comparison result in step Q5 specifically involves comparing each group of patterns in the input color calibration pattern and the imported color calibration pattern. Taking the imported color calibration pattern as the standard, the large square of the input color calibration pattern is completely overlapped, the small square of the input color calibration pattern is hidden, and the color square of the input color calibration pattern is extracted and placed into the small square of the imported color calibration pattern until the small square is completely filled with the color square. The difference between the coordinate parameters before and after the movement is used as the benchmark for adjusting the control parameters of the printer system.

[0048] Even better, in step Q5, when analyzing and comparing the results, an image segmentation algorithm is used to precisely subdivide the color calibration pattern into numerous tiny regions according to the logical structure of the pattern, using combinations of large squares, small squares, and color blocks as basic units. For each unit, a moment-based method is used to determine the geometric center. For a discrete set of pixels (constituting pattern units), the zeroth moment can be used to calculate the area of ​​the region, and the first moment is used to determine the centroid coordinates. By comparing the centroid coordinates of the same units in the input pattern and the imported pattern, the horizontal error Δx and the vertical error Δy are obtained. For example, the centroid coordinates of a small square color block combination unit are (x1, y1) in the input pattern and (x2, y2) in the imported pattern. Therefore, the horizontal error Δx = x2 - x1 and the vertical error Δy = y2 - y1. In this way, the displacement error of the overall pattern is broken down into each key component, avoiding information omissions caused by general calculations.

[0049] In color deviation analysis, the color space is converted to LAB, which simulates human visual perception, making color difference assessment more closely resemble actual visual effects. For each color square, LAB values ​​are extracted from the image color model. Let the LAB values ​​of the entered pattern color square be (L1, a1, b1), and the corresponding imported pattern square be (L2, a2, b2). The lightness difference ΔL = L2 - L1, the chromaticity difference Δa = a2 - a1, and the hue difference Δb = b2 - b1. These three dimensions of difference comprehensively characterize the color deviation, providing precise data support for subsequent corrections of single color deviations or adjustments to complex color combinations.

[0050] A thorough investigation into the characteristics of printing tasks reveals that, in business document printing scenarios, the neatness and clarity of text are paramount. Horizontal color registration accuracy directly affects line spacing and character spacing; therefore, the horizontal displacement error weight w is crucial. x It can be set to 0.6, the vertical displacement error weight w y Set to 0.4, and the total weight of color deviation to 0. For art poster printing, color reproduction is extremely critical; brightness, chroma, and hue affect the image's depth and visual impact. x w y Set each to 0.2, w L w a w b Set them to 0.2 respectively.

[0051] Construct the weighted error calculation formula E = w x Δx+w y Δy+w L ΔL+w a Δa+w b Δb. Based on the printer's internal physical model and control logic, a mapping relationship between errors and control parameters is established. For example, the horizontal displacement error is related to the pulse frequency of the printhead's horizontal stepper motor. When Δx is not 0, the pulse frequency is adjusted according to a pre-determined proportional coefficient. Color deviation is related to the voltage regulation of the ink supply system. By adjusting the voltage, the ink ejection volume is changed to achieve color correction, accurately converting the weighted error into specific control parameter adjustment amounts.

[0052] After the first round of comparison calibration, return to step S2 with the adjusted control parameters and print the color calibration pattern again. Repeat the series of actions such as data entry and comparison to start a new calibration cycle. In each iteration, closely monitor the error correction effect. If it is found that the color deviation has improved after the previous round of adjustments but still does not meet the standard, the next round will adjust the error correction accordingly. L w a w b Increase the weight by 0.1 while simultaneously decreasing the displacement error weight by the same amount. Calculate the rate of change of the comprehensive weighted error before and after each iteration, using the following formula: Where E n E is the comprehensive weighted error of the nth round. n+1 This is the (n+1)th round. When the decrease is less than the set 1% threshold for two consecutive rounds, it means that the calibration process is complete, and the parameters at this point can stably output high-quality color matching effects.

[0053] An apparatus for color matching calibration of channels within the same nozzle includes at least one processor, at least one memory, and computer program instructions stored in the memory. When the computer program instructions are executed by the processor, they implement the aforementioned method for obtaining color matching calibration of channels within the same nozzle.

[0054] A storage medium storing computer program instructions that, when executed by a processor, implement the aforementioned method for color matching calibration of channels within the same printhead.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for color calibration of channels within the same nozzle, characterized in that: The steps include: S1, obtaining a color calibration pattern and importing it into a printer system; S2, according to step S1, printing a color calibration pattern; S3, inputting the color calibration pattern printed in step S2 into the image processing software; S4, importing the color calibration pattern of step S1 into the image processing software; S5, comparing the color calibration pattern entered in step S3 with the color calibration pattern imported in step S4 and calibrating the control parameters of the printer system according to the comparison result.

2. A method for color calibration of channels within the same nozzle according to claim 1, characterized in that: In step S1, the color calibration pattern is specifically a plurality of groups of patterns consisting of a plurality of large squares, small squares and color squares in a grid format, wherein the color square is placed in the middle of the small square, the small square is placed in the middle of the large square, and adjustment parameters of the same size as in the printer system are set below each group of patterns.

3. A method for color calibration of channels within the same nozzle according to claim 1, characterized in that: The step S3 is specifically to completely scan the color calibration pattern printed out in step S2 and enter it into the image processing software, and adjust the size of the entered color calibration pattern in the image processing software.

4. A method for color calibration of channels within the same printhead according to claim 1, characterized in that: The step of adjusting the size of the input color calibration pattern in the image processing software comprises the following steps: L1, obtain the edge information of the entered color calibration pattern; L2, obtain the edge parameters of the printing paper; L3, adjust the edge parameters of the entered color calibration pattern in the same proportion as the edge parameters of the printing paper; L4, repeat steps L1-L3 until the edge parameters of the entered color calibration pattern are exactly the same as the edge parameters of the printing paper.

5. A method for color calibration of channels within the same printhead according to claim 1, characterized in that: In step S2, before printing, the print preview image is captured to determine the specific position of the color calibration pattern on the printing paper, specifically, taking the middle of the printing paper as the center point, and obtaining the coordinate parameters of the four corners of the color calibration pattern.

6. A method for color calibration of channels within the same nozzle according to claim 1, characterized in that: The operation steps of step S5 in the image processing software are as follows: Q1, adjusting the transparency of the color calibration pattern imported in step S4 to 50-70%; Q2, placing the color calibration pattern obtained in step Q1 to the print preview position in step S2; Q3, placing the color calibration pattern obtained in step S3 to the print preview position in step S2; Q4, using an image recognition method, identifying and comparing the two patterns in steps Q2 and Q3; Q5, output comparison results.

7. A method for color calibration of channels within the same printhead according to claim 1, characterized in that: The comparison result in step Q5 is, specifically, to compare each group of patterns in the recorded color calibration pattern and the imported color calibration pattern, take the imported color calibration pattern as the standard, completely overlap the large square of the recorded color calibration pattern, hide the small square of the recorded color calibration pattern, extract the color square of the recorded color calibration pattern and place it in the small square of the imported color calibration pattern until the small square is completely filled with the color square, and use the difference between the coordinate parameters before and after the movement as the basis for adjusting the control parameters of the printer system.

8. A device for color calibration of channels in the same nozzle, characterized in that: The method comprises at least one processor, at least one memory and computer program instructions stored in the memory, and when the computer program instructions are executed by the processor, the method according to any one of claims 1 to 7 is implemented.

9. A storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method described in any one of claims 1 to 7 is implemented.

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