Spray head voltage adjusting method and device based on camera automatic identification printing color blocks and storage medium

Abstract

The invention discloses a nozzle voltage adjustment method and device based on camera automatic identification printing color blocks and a storage medium, and relates to the technical field of printing device calibration, and the method comprises the steps: controlling a printing device to output a pattern containing each nozzle independent test area and color blocks; acquiring chromaticity distribution data through an image acquisition device, and extracting characteristic parameters such as brightness and saturation; determining a reference characteristic parameter based on a reference selection rule, and calculating a deviation value between each test area and the reference; an adjustment instruction is generated according to the mapping relation between the deviation value and the voltage adjustment amount, verification printing and iterative optimization are carried out after implementation until the precision is met, and through dynamic selection of a reference color block, LAB color space chromatic aberration calculation, voltage sensitivity coefficient matrix mapping and aging compensation, the adjustment precision and efficiency are improved, the dependence on artificial experience is reduced, and the adjustment precision and efficiency are improved. The method is suitable for nozzle calibration of high-precision printing equipment.

Description

Technical Field

[0001] This invention relates to the field of printing equipment calibration technology, and more specifically, to a method, device, and storage medium for adjusting printhead voltage based on automatic camera recognition of printing color blocks. Background Technology

[0002] In the maintenance and debugging of modern printing equipment, the uniformity of the printhead plays a crucial role in print quality. Traditional methods rely on printing uniform solid color blocks and the visual observation and experience of technicians to judge the uniformity of the printhead, which has many shortcomings. First, due to differences in manufacturing processes and materials, different batches of printheads will produce varying shades when printing the same color block, making it difficult to adjust the printhead voltage uniformly and affecting the consistency of print quality. Second, printheads gradually age during use, and the degree of aging of new and old printheads is different. Even when printing the same color block using the same voltage, obvious color differences will appear, making the printhead performance unstable and difficult to guarantee print results. In addition, traditional methods rely on the subjective judgment of technicians, which is not only time-consuming but also prone to judgment errors due to different color sensitivity of personnel, affecting the debugging effect. To solve these problems, this invention proposes a printhead voltage adjustment method based on automatic identification of printed color blocks by a camera. By scanning the printed color block with a high-precision camera and performing data analysis, automatic and accurate printhead voltage adjustment is achieved, improving the stability and consistency of print quality and reducing the reliance on the experience of technicians.

[0003] In summary, existing technologies suffer from inconsistent print quality and low debugging efficiency due to batch variations, aging issues, and subjective judgment in printhead voltage adjustment methods. Summary of the Invention

[0004] In order to overcome the problems of unstable print quality and low debugging efficiency caused by batch differences, aging issues and subjective judgment in the existing printhead voltage adjustment methods, this invention discloses a printhead voltage adjustment method, device and storage medium based on automatic identification of printed color blocks by camera, which can effectively solve the above-mentioned technical problems.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A printhead voltage adjustment method based on camera-based automatic recognition of printed color blocks includes the following steps:

[0007] The printing equipment is controlled to output a preset color block pattern, which includes a test area printed independently by each printhead, ensuring that each printhead participates in the printing process.

[0008] The color block pattern is scanned by an image acquisition device to obtain the color block depth data of each printhead, forming the color distribution data of the color block pattern. The color distribution data includes color feature parameters of each test area, including brightness value, color coordinate difference, color saturation and optical density value.

[0009] Record the current voltage value used by each nozzle and input it into the system;

[0010] Based on a preset benchmark selection rule, a benchmark feature parameter is determined from the chromaticity distribution data. The benchmark selection rule includes: selecting the median of the feature parameter in the chromaticity distribution data, the average of a preset number of optimal feature parameters, or the feature parameter of the test area with the highest matching degree with the preset standard color card, and using the color block corresponding to the benchmark feature parameter as the benchmark color block.

[0011] The deviation values ​​of the characteristic parameters of each test area from the reference characteristic parameters are calculated, including establishing a two-dimensional color difference matrix containing the nozzle position coordinates, performing spatial filtering on the color difference matrix to eliminate local outliers, and calculating the Euclidean distance between each node in the filtered matrix and the reference value as the final deviation value, so as to realize the comparative analysis of the color blocks of other nozzles and the reference color blocks.

[0012] Based on the mapping relationship between the deviation value and the voltage adjustment amount, a voltage adjustment instruction for each nozzle is generated, including constructing a nozzle voltage-chromaticity response curve database, querying the database for the corresponding optimal voltage adjustment amount based on the current deviation value, and calculating the theoretical adjustment amount through an interpolation algorithm when there is no matching record in the database, so as to obtain the recommended voltage adjustment value for each nozzle.

[0013] Adjust the voltage of each nozzle according to the recommended voltage adjustment value;

[0014] After voltage adjustment, a verification print is performed. The secondary deviation between the verification print color block and the reference color block is compared. When the secondary deviation exceeds the threshold, iterative adjustment is performed until the accuracy requirements are met.

[0015] Preferably, the benchmark selection rule specifically includes the step of dynamically selecting the optimal color block:

[0016] For each color patch, calculate the color uniformity score using the following formula:

[0017]

[0018] in, The standard deviation of brightness, The average saturation, To preset standard hue values, This is the measured average hue. , , The weighting coefficients are and satisfy the following conditions: + + = 1;

[0019] Choose the color block with the highest score as the benchmark.

[0020] Preferably, the calculation of the deviation value includes calculation in the LAB color space. Color difference value:

[0021]

[0022] when When the preset threshold is exceeded, the voltage adjustment command generation step is activated.

[0023] Preferably, the mapping relationship is constructed through a voltage sensitivity coefficient matrix, and the specific steps include:

[0024] Apply a stepped voltage to the test nozzle and print a test color patch;

[0025] Establish a voltage-color difference gradient model to extract the brightness difference caused by a unit voltage change. , saturation difference ΔC, hue difference ΔH change rate;

[0026] The rate of change is integrated into a three-dimensional coefficient matrix, which serves as the basis for mapping the deviation value to the voltage adjustment amount.

[0027] Preferably, it also includes a database dynamic update step:

[0028] Record the actual printing effect data after each adjustment, including the voltage value before and after the adjustment and the corresponding color difference value;

[0029] The printhead voltage-color response curve database is dynamically updated based on historical adjustment data using a linear regression algorithm, and the update cycle is adaptively adjusted according to the printing volume.

[0030] Preferably, an image preprocessing step is included before acquiring the chromaticity distribution data:

[0031] White balance calibration is performed using the camera's built-in color correction module to eliminate color deviations caused by ambient light sources;

[0032] A mapping table between the nozzle and the image region is established based on the color block positioning coordinates. The mapping table includes the nozzle number, image pixel coordinates, and geometric distortion correction parameters.

[0033] Preferably, the generation of the voltage adjustment command further includes aging compensation:

[0034] The aging index is calculated based on the cumulative working time of the nozzle. ;

[0035] The adjustment magnitude is weighted and corrected using the following formula:

[0036]

[0037] in, Basic adjustment amount, It is an aging compensation factor, determined through training with historical data.

[0038] Preferably, an electronic device includes:

[0039] The color block generation module is used to control the printing equipment to output a pattern that includes independent test areas for each printhead and color blocks.

[0040] The image analysis module is used to process the color distribution data acquired by the image acquisition device. It includes a color calibration unit, a region recognition unit, and a feature extraction unit. The color calibration unit corrects the ambient light source deviation, the region recognition unit locates the test area corresponding to each nozzle, and the feature extraction unit calculates the standardized color feature vector.

[0041] The voltage calculation module is used to generate adjustment instructions based on the mapping relationship between the deviation value and the voltage adjustment amount. It includes the functions of storing the voltage sensitivity coefficient matrix and executing the interpolation algorithm.

[0042] The verification and feedback module is used to perform effect verification and iterative optimization after adjustment, compare secondary deviations, and trigger a new round of adjustment process.

[0043] Preferably, it also includes a color analysis acceleration module that communicates with the camera, the module comprising dedicated hardware circuitry for real-time calculation of LAB color conversion and... Color difference value, supporting parallel processing of feature extraction for multi-nozzle test areas.

[0044] Preferably, a computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the adjustment method as described above.

[0045] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention effectively solves the problems of unstable print quality and low debugging efficiency caused by batch differences, aging issues, and subjective judgment in existing technologies through an innovative printhead voltage adjustment method. First, by controlling the printing equipment to output a preset color block pattern containing independent test areas and gradient color levels for each printhead, it ensures that each printhead participates in printing, providing a basis for evaluating printhead performance. Second, by using an image acquisition device to scan the color block pattern, it obtains chromaticity distribution data containing color feature parameters such as brightness value, chromaticity coordinate difference, color saturation, and optical density value. Compared with traditional methods, this can more comprehensively and accurately reflect the printhead performance. The actual printing effect solved the problem of inconsistent color block shades caused by batch differences. Furthermore, based on preset benchmark selection rules, benchmark characteristic parameters were determined, and the deviation values ​​of each test area were calculated. This process, through the establishment of a two-dimensional color difference matrix and spatial filtering, eliminated local outliers, improved the accuracy of the analysis, and avoided the impact of printhead performance instability due to aging on the adjustment results. In addition, adjustment instructions were generated based on the mapping relationship between deviation values ​​and voltage adjustment amounts, a printhead voltage-color response curve database was constructed, and theoretical adjustment amounts were calculated through interpolation algorithms when no matching records were available, achieving precise voltage adjustment and overcoming the reliance on technical expertise in traditional methods. To address the shortcomings of subjective judgment by technicians, this invention also includes a dynamic database update step. Based on historical adjustment data, a linear regression algorithm is used to dynamically update the database, enabling the system to adaptively adjust according to print volume, further improving the accuracy and adaptability of the adjustment. In the image preprocessing step before acquiring color distribution data, white balance calibration is performed through the camera's built-in color correction module, eliminating color deviations caused by ambient light sources and improving data reliability. The aging compensation mechanism calculates the aging index based on the cumulative working time of the printhead and performs weighted correction on the adjustment range, further ensuring the accuracy of the adjustment. This invention also provides an electronic device, including a color block generation module, an image analysis module, a voltage calculation module, and a verification feedback module, as well as a color analysis acceleration module that communicates with the camera. These modules work together to automate the entire process from color block generation to voltage adjustment, improving debugging efficiency. Furthermore, the computer program stored on a computer-readable storage medium allows the method of this invention to be easily implemented on different devices, showing broad application prospects. In summary, this invention solves the problems in the prior art through innovative technical means, achieving precise adjustment of printhead voltage, improving the stability and consistency of print quality, reducing reliance on technician experience, and improving debugging efficiency, thus possessing significant practical application value. Attached Figure Description

[0046] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary. For those skilled in the art, other embodiments can be derived from the provided drawings without creative effort.

[0047] Figure 1 This is a diagram illustrating the steps of the method of the present invention;

[0048] Figure 2 This is a structural diagram of the electronic device of the present invention. Detailed Implementation

[0049] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0050] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;

[0051] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0052] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0053] Example 1

[0054] Please see Figure 1 A printhead voltage adjustment method based on camera-based automatic recognition of printed color blocks includes the following steps:

[0055] The printing device is controlled to output a preset color block pattern, which includes test areas printed independently by each printhead, ensuring that each printhead participates in printing; in some embodiments, each test area has a gradient color level distributed according to a preset rule.

[0056] The color block pattern is scanned by an image acquisition device to obtain the color block depth data of each printhead, forming the color distribution data of the color block pattern. The color distribution data includes color feature parameters of each test area, including brightness value, color coordinate difference, color saturation and optical density value.

[0057] Record the current voltage value used by each nozzle and input it into the system;

[0058] Based on a preset benchmark selection rule, a benchmark feature parameter is determined from the chromaticity distribution data. The benchmark selection rule includes: selecting the median of the feature parameter in the chromaticity distribution data, the average of a preset number of optimal feature parameters, or the feature parameter of the test area with the highest matching degree with the preset standard color card, and using the color block corresponding to the benchmark feature parameter as the benchmark color block.

[0059] The deviation values ​​of the characteristic parameters of each test area from the reference characteristic parameters are calculated, including establishing a two-dimensional color difference matrix containing the nozzle position coordinates, performing spatial filtering on the color difference matrix to eliminate local outliers, and calculating the Euclidean distance between each node in the filtered matrix and the reference value as the final deviation value, so as to realize the comparative analysis of the color blocks of other nozzles and the reference color blocks.

[0060] Based on the mapping relationship between the deviation value and the voltage adjustment amount, a voltage adjustment instruction for each nozzle is generated, including constructing a nozzle voltage-chromaticity response curve database, querying the database for the corresponding optimal voltage adjustment amount based on the current deviation value, and calculating the theoretical adjustment amount through an interpolation algorithm when there is no matching record in the database, so as to obtain the recommended voltage adjustment value for each nozzle.

[0061] Adjust the voltage of each nozzle according to the recommended voltage adjustment value;

[0062] After voltage adjustment, a verification print is performed. The secondary deviation between the verification print color block and the reference color block is compared. When the secondary deviation exceeds the threshold, iterative adjustment is performed until the accuracy requirements are met.

[0063] The benchmark selection rule specifically includes the step of dynamically selecting the optimal color block:

[0064] For each color patch, calculate the color uniformity score using the following formula:

[0065]

[0066] in, The standard deviation of brightness, The average saturation, To preset standard hue values, This is the measured average hue. , , The weighting coefficients are and satisfy the following conditions: + + = 1;

[0067] Choose the color block with the highest score as the benchmark.

[0068] The calculated deviation value includes calculations performed in the LAB color space. Color difference value:

[0069]

[0070] when When the preset threshold is exceeded, the voltage adjustment command generation step is activated.

[0071] The mapping relationship is constructed through a voltage sensitivity coefficient matrix, and the specific steps include:

[0072] Apply a stepped voltage to the test nozzle and print a test color patch;

[0073] Establish a voltage-color difference gradient model to extract the brightness difference caused by a unit voltage change. , saturation difference ΔC, hue difference ΔH change rate;

[0074] The rate of change is integrated into a three-dimensional coefficient matrix, which serves as the basis for mapping the deviation value to the voltage adjustment amount.

[0075] It also includes the steps for dynamic database updates:

[0076] Record the actual printing effect data after each adjustment, including the voltage value before and after the adjustment and the corresponding color difference value;

[0077] The printhead voltage-color response curve database is dynamically updated based on historical adjustment data using a linear regression algorithm, and the update cycle is adaptively adjusted according to the printing volume.

[0078] Image preprocessing steps are also included before acquiring chromaticity distribution data:

[0079] White balance calibration is performed using the camera's built-in color correction module to eliminate color deviations caused by ambient light sources;

[0080] A mapping table between the nozzle and the image region is established based on the color block positioning coordinates. The mapping table includes the nozzle number, image pixel coordinates, and geometric distortion correction parameters.

[0081] The generation of voltage adjustment commands also includes aging compensation:

[0082] The aging index is calculated based on the cumulative working time of the nozzle. ;

[0083] The adjustment magnitude is weighted and corrected using the following formula:

[0084]

[0085] in, Basic adjustment amount, It is an aging compensation factor, determined through training with historical data.

[0086] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the adjustment method as described above.

[0087] This embodiment uses a large advertising inkjet printer equipped with 24 printheads and supporting high-precision color output as the application object. It is used to solve the problem of uneven printing color blocks caused by individual differences in printheads, long-term aging, and changes in environmental temperature and humidity. The equipment uses water-based ink and the daily printing material is PVC roll. It is required to control the color consistency error of the same batch of printed products within a range that is imperceptible to the human eye by automatically adjusting the printhead voltage.

[0088] In practice, the system sends instructions to the inkjet printer to control it to print a preset color block pattern on standard PVC rolls. The pattern contains 24 independent test areas, each corresponding to one of the 24 printheads. Each test area has 6 levels of color gradient (covering a range of colors from light to dark) distributed from low to high. The edges of the areas are marked with black positioning frames to facilitate camera recognition of the boundaries. The pattern printing parameters are uniformly set to standard resolution to ensure that each printhead outputs test color blocks under the same conditions.

[0089] Image acquisition: An industrial-grade color camera (equipped with a high-resolution lens) is used to photograph the printed color block pattern. During the shooting, a ring light source is used to provide stable illumination to avoid interference from ambient light. The camera is kept at a fixed distance from the pattern to ensure that each test area occupies enough pixels in the image in order to accurately extract color information.

[0090] Image preprocessing: The camera's built-in color correction module automatically performs white balance calibration to eliminate color temperature deviations caused by different ambient light sources, such as natural light and indoor lighting, ensuring consistent color acquisition.

[0091] Based on the positioning box at the edge of the test area, the system automatically establishes a mapping table between the nozzles and the image area, records the image pixel coordinates corresponding to each nozzle, and eliminates the image distortion caused by the shooting angle through a geometric distortion correction algorithm.

[0092] Extracting color feature parameters: Extracting multi-dimensional color feature parameters from the image of each test area, including brightness value (reflecting the lightness or darkness of the color), chromaticity coordinate difference (characterizing the positional deviation of the color in the color space), color saturation (reflecting the vividness of the color), and optical density value (reflecting the intensity of the color). These parameters together constitute the basic data for evaluating the printhead printing effect.

[0093] The baseline is determined by dynamically selecting the optimal color block, as follows:

[0094] Calculate the color uniformity score: For the test area corresponding to each printhead, calculate the score using the following formula:

[0095] in, The standard deviation of brightness, The average saturation, To preset standard hue values, This is the measured average hue. , , The weighting coefficients are and satisfy the following conditions: + + = 1, which are used to balance the effects of brightness uniformity, saturation and hue deviation on the score.

[0096] Selection of benchmark: The scores of the 24 test areas are sorted, and the area with the highest score is selected as the benchmark. The corresponding color feature parameters are the benchmark feature parameters. This benchmark represents the ideal printing effect and is the reference standard for deviation calculation.

[0097] Construct a two-dimensional color difference matrix: Using the physical position coordinates of the printhead as the horizontal axis and the extracted color feature parameters as the vertical axis, construct a two-dimensional color difference matrix that includes all printheads, and intuitively present the differences between each printhead and the reference.

[0098] Spatial filtering: Spatial filtering is performed on the color difference matrix to eliminate local outliers caused by accidental nozzle clogging, ink splashing, etc., and to ensure the accuracy of deviation calculation.

[0099] Calculate the final deviation value: In the LAB color space, calculate the Euclidean distance between each node in the filtered matrix and the reference value as the final deviation value. The formula is:

[0100] in, This represents the brightness difference, which is the absolute value of the difference between the values ​​of two colors in the L channel. This represents the difference on the a channel (red-green axis), that is, the absolute value of the difference between the values ​​of the two colors on the a channel; The color difference is the difference on the b channel (yellow-blue axis), specifically the absolute value of the difference between the numerical values ​​of two colors on the b channel. This represents the distance between two colors in the LAB color space. A larger value indicates a greater difference between the two colors. When the preset threshold is exceeded, the system activates the voltage adjustment instruction generation step to adjust the printhead voltage of the printing device, thereby reducing color difference and improving print quality.

[0101] Establishing a mapping relationship: A mapping relationship between deviation values ​​and voltage adjustment amounts is established using a voltage sensitivity coefficient matrix. Specifically, different stepped voltages are applied to each printhead, and test color patches are printed. The color deviation change corresponding to each voltage change is recorded, establishing a voltage-color difference gradient model and extracting the brightness difference caused by a unit voltage change. The rates of change of saturation difference ΔC and hue difference ΔH are integrated into a three-dimensional coefficient matrix, which serves as the basis for mapping.

[0102] Query and calculate adjustment amount: The system constructs a database of nozzle voltage-chromaticity response curves. Based on the currently calculated deviation value, it queries the database for the corresponding optimal voltage adjustment amount. When there is no matching record in the database, the theoretical adjustment amount is calculated through interpolation algorithm to ensure that each nozzle can obtain a suitable voltage adjustment suggestion.

[0103] Aging Compensation: The aging index is calculated based on the cumulative working time of each nozzle, and the adjustment range is weighted and corrected. The formula is as follows: in, Basic adjustment amount, An aging compensation factor (determined through training with historical data) is used to appropriately increase the adjustment range for nozzles with longer operating times and higher aging levels, in order to compensate for the impact of performance degradation.

[0104] Voltage adjustment: The system sends the generated voltage adjustment command to the printhead control unit of the inkjet printer, and each printhead adjusts its own voltage parameters according to the command.

[0105] Verification Printing: After adjustment, control the inkjet printer to reprint the color block pattern, and use the same image acquisition and analysis process to obtain the colorimetric data of the verification printed color block.

[0106] Iterative optimization: The secondary deviation between the printed color patch and the reference color patch is compared and verified. When the secondary deviation exceeds the preset threshold, the above steps are repeated for iterative adjustment until the deviation meets the accuracy requirements. At the same time, the system records the voltage value and the corresponding color difference value before and after each adjustment. Based on these historical data, the printhead voltage-color response curve database is dynamically updated using a linear regression algorithm. The update cycle is adaptively adjusted according to the printing volume of the device (the larger the printing volume, the higher the update frequency).

[0107] Example 2

[0108] Please see Figure 2 An electronic device, comprising:

[0109] The color block generation module is used to control the printing equipment to output color block patterns that include independent test areas for each printhead and gradient color levels;

[0110] The image analysis module is used to process the color distribution data acquired by the image acquisition device. It includes a color calibration unit, a region recognition unit, and a feature extraction unit. The color calibration unit corrects the ambient light source deviation, the region recognition unit locates the test area corresponding to each nozzle, and the feature extraction unit calculates the standardized color feature vector.

[0111] The voltage calculation module is used to generate adjustment instructions based on the mapping relationship between the deviation value and the voltage adjustment amount. It includes the functions of storing the voltage sensitivity coefficient matrix and executing the interpolation algorithm.

[0112] The verification and feedback module is used to perform effect verification and iterative optimization after adjustment, compare secondary deviations, and trigger a new round of adjustment process.

[0113] It also includes a color analysis acceleration module that communicates with the camera, the module containing dedicated hardware circuitry for real-time calculation of LAB color conversion and... Color difference value, supporting parallel processing of feature extraction for multi-nozzle test areas.

[0114] This electronic device is a dedicated intelligent calibration controller for inkjet printers. The hardware uses an industrial-grade motherboard, integrating a high-speed processor, image acquisition interface, voltage control module, and data storage unit. The software modules include color block generation, image analysis, voltage calculation, verification feedback, and color analysis acceleration modules. All modules work together to achieve automatic adjustment of printhead voltage.

[0115] The color block generation module connects to the inkjet printer via a communication interface. It can generate control commands based on user-defined parameters, such as the number of color levels and the size of the color blocks. This commands control the inkjet printer to output color block patterns that include independent test areas for each printhead and gradient color levels. Users can adjust the pattern parameters through the device's operating interface. The module converts the parameters into a command format that the inkjet printer can recognize, ensuring the standardization and consistency of the test patterns.

[0116] The image analysis module includes a color calibration unit, a region recognition unit, and a feature extraction unit, with the following specific functions:

[0117] After receiving image data from the camera, the color calibration unit automatically calls the color correction algorithm to perform white balance calibration, eliminates the influence of ambient light on color acquisition, and outputs a calibrated standardized image.

[0118] The region recognition unit locates the test area corresponding to each nozzle based on the positioning box in the image and uses image recognition algorithm to establish the mapping relationship between nozzle number and image pixel coordinates, and performs geometric distortion correction on the image to ensure the accuracy of region recognition.

[0119] The feature extraction unit extracts color feature parameters such as brightness value, chromaticity coordinate difference, color saturation and optical density value from each test area, and standardizes these parameters to form feature vectors, providing data support for subsequent deviation calculation.

[0120] The voltage calculation module is the core calculation unit, responsible for calculating the voltage adjustment of the nozzle based on the deviation value. Its specific functions include:

[0121] The storage voltage sensitivity coefficient matrix records the impact rate of unit voltage change on brightness, saturation, and hue, and is the key basis for mapping deviation values ​​to voltage adjustment amounts.

[0122] The built-in interpolation algorithm calculates the theoretical adjustment amount by interpolating neighboring data when the nozzle's deviation value has no matching record in the database, ensuring that each nozzle can receive appropriate adjustment suggestions.

[0123] By combining the aging index and aging compensation factor of the nozzle, the basic adjustment amount is corrected to generate the final voltage adjustment command.

[0124] The verification feedback module is used to evaluate the voltage adjustment effect and trigger iterative optimization. The specific process is as follows:

[0125] Receive the adjusted verification print color patch data and calculate its quadratic deviation from the reference color patch.

[0126] When the secondary deviation exceeds the preset threshold, a new round of voltage adjustment process is automatically triggered until the deviation meets the accuracy requirements.

[0127] Record detailed data for each adjustment, such as voltage and color difference values ​​before and after the adjustment, to provide raw data for dynamic updates of the database.

[0128] The color analysis acceleration module is equipped with dedicated hardware circuitry to accelerate the color data processing, supporting parallel processing of feature extraction from multiple printhead test areas and real-time calculation of LAB color conversion. Color difference values ​​significantly shorten data processing time, ensuring that the device can respond quickly and complete calibration.

[0129] After the equipment is started, the color block generation module first controls the inkjet printer to output test color block patterns; the image acquisition device captures the patterns and transmits the data to the image analysis module. After preprocessing and feature extraction, the color feature parameters of each printhead are obtained; the voltage calculation module uses the reference feature parameters to calculate the deviation value and generate a voltage adjustment command; after the inkjet printer performs the adjustment, the verification feedback module evaluates the adjustment effect through a second print. If it does not meet the standard, it triggers iteration until the accuracy requirements are met. The entire process does not require manual intervention and realizes fully automatic and precise adjustment of printhead voltage.

[0130] The above methods and equipment significantly improve the color consistency of inkjet printers, reduce material waste and rework caused by uneven color blocks, and reduce reliance on operator experience. They are suitable for the daily maintenance and calibration of various high-precision printing equipment.

[0131] The same or similar labels correspond to the same or similar parts;

[0132] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0133] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for adjusting printhead voltage based on automatic camera recognition of printed color blocks, characterized in that, Includes the following steps: The printing equipment is controlled to output a preset color block pattern, which includes a test area printed independently by each printhead, ensuring that each printhead participates in the printing process. The color block pattern is scanned by an image acquisition device to obtain the color block depth data of each printhead, forming the color distribution data of the color block pattern. The color distribution data includes color feature parameters of each test area, including brightness value, color coordinate difference, color saturation and optical density value. Record the current voltage value used by each nozzle and input it into the system; Based on a preset benchmark selection rule, a benchmark feature parameter is determined from the chromaticity distribution data. The benchmark selection rule includes: selecting the median of the feature parameter in the chromaticity distribution data, the average of a preset number of optimal feature parameters, or the feature parameter of the test area with the highest matching degree with the preset standard color card, and using the color block corresponding to the benchmark feature parameter as the benchmark color block. The deviation values ​​of the characteristic parameters of each test area from the reference characteristic parameters are calculated, including establishing a two-dimensional color difference matrix containing the nozzle position coordinates, performing spatial filtering on the color difference matrix to eliminate local outliers, and calculating the Euclidean distance between each node in the filtered matrix and the reference value as the final deviation value, so as to realize the comparative analysis of the color blocks of other nozzles and the reference color blocks. Based on the mapping relationship between the deviation value and the voltage adjustment amount, a voltage adjustment instruction for each nozzle is generated, including constructing a nozzle voltage-chromaticity response curve database, querying the database for the corresponding optimal voltage adjustment amount based on the current deviation value, and calculating the theoretical adjustment amount through an interpolation algorithm when there is no matching record in the database, so as to obtain the recommended voltage adjustment value for each nozzle. Adjust the voltage of each nozzle according to the recommended voltage adjustment value; After voltage adjustment, a verification print is performed. The secondary deviation between the verification print color block and the reference color block is compared. When the secondary deviation exceeds the threshold, iterative adjustment is performed until the accuracy requirements are met.

2. The adjustment method according to claim 1, characterized in that, The benchmark selection rule specifically includes the step of dynamically selecting the optimal color block: For each color patch, calculate the color uniformity score using the following formula: ； in, The standard deviation of brightness, The average saturation, To preset standard hue values, This is the measured average hue. , , The weighting coefficients are and satisfy the following conditions: + + = 1; Choose the color block with the highest score as the benchmark.

3. The adjustment method according to claim 1, characterized in that, The calculated deviation value includes calculations performed in the LAB color space. Color difference value: ； when When the preset threshold is exceeded, the voltage adjustment command generation step is activated.

4. The adjustment method according to claim 1, characterized in that, The mapping relationship is constructed through a voltage sensitivity coefficient matrix, and the specific steps include: Apply a stepped voltage to the test nozzle and print a test color patch; Establish a voltage-color difference gradient model to extract the brightness difference caused by a unit voltage change. , saturation difference ΔC, hue difference ΔH change rate; The rate of change is integrated into a three-dimensional coefficient matrix, which serves as the basis for mapping the deviation value to the voltage adjustment amount.

5. The adjustment method according to claim 1, characterized in that, It also includes the steps for dynamic database updates: Record the actual printing effect data after each adjustment, including the voltage value before and after the adjustment and the corresponding color difference value; The printhead voltage-color response curve database is dynamically updated based on historical adjustment data using a linear regression algorithm, and the update cycle is adaptively adjusted according to the printing volume.

6. The adjustment method according to claim 1, characterized in that, Image preprocessing steps are included before acquiring chromaticity distribution data: White balance calibration is performed using the camera's built-in color correction module to eliminate color deviations caused by ambient light sources; A mapping table between the nozzle and the image region is established based on the color block positioning coordinates. The mapping table includes the nozzle number, image pixel coordinates, and geometric distortion correction parameters.

7. The adjustment method according to claim 1, characterized in that, The generation of voltage adjustment commands also includes aging compensation: The aging index is calculated based on the cumulative working time of the nozzle. ; The adjustment magnitude is weighted and corrected using the following formula: ； in, Basic adjustment amount, It is an aging compensation factor, determined through training with historical data.

8. An electronic device for implementing the adjustment method according to any one of claims 1-7, characterized in that, include: The color block generation module is used to control the printing equipment to output a pattern that includes independent test areas for each printhead and color blocks. The image analysis module is used to process the color distribution data acquired by the image acquisition device. It includes a color calibration unit, a region recognition unit, and a feature extraction unit. The color calibration unit corrects the ambient light source deviation, the region recognition unit locates the test area corresponding to each nozzle, and the feature extraction unit calculates the standardized color feature vector. The voltage calculation module is used to generate adjustment instructions based on the mapping relationship between the deviation value and the voltage adjustment amount. It includes the functions of storing the voltage sensitivity coefficient matrix and executing the interpolation algorithm. The verification and feedback module is used to perform effect verification and iterative optimization after adjustment, compare secondary deviations, and trigger a new round of adjustment process.

9. The electronic device according to claim 8, characterized in that, It also includes a color analysis acceleration module that communicates with the camera, the module containing dedicated hardware circuitry for real-time calculation of LAB color conversion and... Color difference value, supporting parallel processing of feature extraction for multi-nozzle test areas.

10. A computer-readable storage medium, characterized in that, The device contains a computer program that, when executed by a processor, implements the steps of the adjustment method as described in any one of claims 1-7.

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