A method and system for improving printed image quality based on frequency modulation dots

Abstract

The present application discloses a method and system for improving the quality of printed images based on frequency modulation dots. The method comprises obtaining initial process parameters based on the acquired platemaking machine equipment parameters and the platemaking standard information of each platemaking link in the platemaking process; obtaining frequency modulation dots and corresponding standard dot parameters of different brightness gradation zones of the preprocessed target image; obtaining historical printing grayscale images according to the platemaking machine equipment parameters, determining the equipment imaging characteristics and mesh control adjustment area corresponding to the platemaking machine equipment parameters based on the historical printing grayscale images, and determining the target dot grayscale level and dot dynamic control parameters in combination with the frequency modulation dots and corresponding standard dot parameters of different brightness gradation zones; the dot dynamic control parameters include dot output range parameters based on frequency modulation dots; triggering platemaking printing control instructions according to the target dot grayscale level and dot dynamic control parameters; the present application improves the reproduction quality of printed images.

Description

Technical Field

[0001] The present application relates to the field of printing technology, and in particular to a method and system for improving the quality of printed images based on frequency modulation dots. Background Art

[0002] The hard copy reproduction of images mainly involves the screen plate-making technology of printers and high-end printing plate-making equipment. The screen technology used for hard copy reproduction of images is also called digital image halftone technology. Digital image halftone technology can be divided into two categories, namely amplitude modulation screen and frequency modulation screen. Among them, frequency modulation screen uses the printing technology of frequency modulation dots. The technical feature of frequency modulation dots is that the size of the dots remains unchanged, and the density of the dots is used to express the density of the image; this technology expresses the gradation of the image, that is, the brightness and color depth of the image by controlling the density of the dots.

[0003] At present, most of the commonly used halftone mixed screening is a simple mixture in the traditional sense, that is, frequency modulation screening is used for the light and dark tones of the image (0-10% and 90%-100%), and amplitude modulation screening is used for the middle tone (10%-90%). Since the frequency modulation dots are scattered independent dots, if they are not processed, there will still be problems such as dot loss (dot loss problem caused by the fragility of light tone dots) or plate blurring (printing plate blurring problem caused by the shallow dark tone dots), resulting in low quality of printed image reproduction, so there is room for improvement. Summary of the invention

[0004] In order to improve the reproduction quality of printed images, the present application provides a method and a system for improving the quality of printed images based on frequency modulation dots.

[0005] In the first aspect, the invention objective of the present application is achieved by adopting the following technical solutions:

[0006] A method for improving the quality of printed images based on frequency modulation dots, comprising:

[0007] Performing image preprocessing on the target printing image to obtain a preprocessed target image;

[0008] Based on the acquired plate-making machine equipment parameters and the plate-making standard information of each plate-making link in the plate-making process, the initial process parameters are obtained;

[0009] Acquire frequency modulation dots and corresponding dot standard parameters in different brightness gradation areas of the preprocessed target image based on the initial process parameters;

[0010] Acquire a historical printing grayscale image according to the plate-making machine equipment parameters, determine the equipment imaging characteristics and screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determine the target dot grayscale level and dot dynamic control parameters in combination with the frequency-modulated dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency-modulated dots;

[0011] According to the target dot grayscale level and the dot dynamic control parameter, a plate-making printing control instruction is triggered.

[0012] By adopting the above technical scheme, the target printing image is the target plate-making image content of the plate-making machine, and the target printing image is preprocessed by image processing software to obtain a preprocessed target image suitable for FM dot conversion, wherein the plate-making machine equipment parameters are the initial equipment parameters of the current plate-making machine equipment, and the plate-making standard information of each plate-making link is obtained through the plate-making machine equipment parameters and the plate-making standard information of each plate-making link, and the initial process parameters according to the process standard requirements corresponding to the current printing materials and printing equipment characteristics are obtained, and the FM dots and corresponding dot standard parameters in different brightness gradation zones under the current plate-making machine equipment conditions are obtained through the initial process parameters, and the dot standard parameters are dot parameters that meet the high standards of relevant printing image quality; in order to detect the plate-making printing quality of the current plate-making machine, effectively improve the control accuracy of the plate-making machine, and improve the quality of printed images, the present application obtains historical printing grayscale images of the same plate-making machine equipment parameters to determine the device imaging characteristics and screen type control adjustment area based on the current plate-making machine. domain, the imaging characteristics of the device include the output linearization characteristics and dot shape characteristics of the device, and the screen type control adjustment area is an unstable area of ​​the dot shape, and the screen type of this area needs to be adjusted; at this time, the target dot grayscale level and dot dynamic control parameters are determined in combination with the FM dots in different brightness gradation areas of the current platemaking machine equipment and the corresponding dot standard parameters, so as to determine the dot gradation area that needs to be adjusted, the corresponding dot position and the specific adjustment content, so as to achieve high-quality FM dot hanging effect based on different density areas and on the basis of the screen type formed by the existing FM dots, combined with the requirements of the dot shape of the printed image for the stability of the device output, and finely control the dot shape. By confirming the FM dots to be adjusted in advance and determining the adjustment content, it is helpful to reduce the problems of FM dot loss and plate blurring. Finally, according to the target dot grayscale level and dot dynamic control parameters, the platemaking printing control instruction is triggered, which is conducive to achieving the purpose of improving the quality of printed image reproduction.

[0013] In a preferred example of the present application: the historical printing grayscale image is obtained according to the plate-making machine equipment parameters, the device imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters are determined based on the historical printing grayscale image, and the target dot grayscale level and dot dynamic control parameters are determined in combination with the frequency modulation dots in the different brightness gradation areas and the corresponding dot standard parameters, including:

[0014] Acquire a historical printing grayscale image based on the plate-making machine equipment parameters, wherein the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the plate-making machine equipment parameters;

[0015] Determine dot shape information and a plurality of mesh density areas based on the historical printing grayscale image, and determine device imaging characteristics and mesh control adjustment areas corresponding to the platemaking machine equipment parameters in combination with device output stability and output linearization characteristics of the platemaking machine equipment parameters;

[0016] Based on the imaging characteristics of the device and the screen type control adjustment area, the corresponding output grayscale level information is obtained, and according to a preset output grayscale dynamic statistical algorithm, a number of target frequency modulation control dots are determined in the frequency modulation dots in the different brightness gradation areas;

[0017] Based on the device imaging characteristics of the platemaking machine device parameters, the screen type control adjustment area, a number of the target frequency modulation control dots and the corresponding dot standard parameters, the target dot grayscale level and dot dynamic control parameters are determined.

[0018] By adopting the above technical scheme, the historical printing grayscale image is a reference grayscale image obtained by platemaking printing based on the current platemaking machine process parameter standard setting. Image quality evaluation is performed based on the historical printing grayscale image, and the output stability and image quality output evaluation results of the current platemaking machine equipment can be obtained to analyze the characteristics of the platemaking machine equipment and the printing effect; for the plate number repetition function based on the current platemaking machine equipment parameters, the frequency modulation dots in different brightness gradation areas are repeatedly output multiple times to obtain the platemaking machine process parameter setting with better repeatability and batch replication consistency, so as to obtain the platemaking machine equipment with higher printing image quality; specifically, the dots in the current frequency modulation dot mode are determined based on the historical printing grayscale image. Shape information and several corresponding mesh density areas. The mesh density area is an area where FM dots are densely distributed. The mesh density area is an area where dot loss, plate blurring, and other factors that may affect the reproduction of printed image details are more likely to occur. It is a key analysis area that can provide feedback on the printing quality and image accuracy of the platemaking machine. Therefore, after determining the equipment imaging characteristics and mesh control adjustment area of ​​the corresponding platemaking machine equipment parameters, in order to obtain a printed image with higher quality in the subsequent printing process, this application determines the target dot grayscale level and dot dynamic control parameters based on FM dot technology in the printing process by outputting a grayscale dynamic statistical algorithm, so as to achieve dynamic control of the printing accuracy of the FM dots and realize efficient adjustment of the FM network.

[0019] In a preferred example of the present application: the dot dynamic control parameter includes a dot enlargement threshold value set corresponding to different types of printing paper and dot standard parameters; after triggering the platemaking printing control instruction according to the target dot gray level and the dot dynamic control parameter, it includes:

[0020] Based on the target frequency modulation control dots, generating a plurality of grayscale control units in the mesh control adjustment area;

[0021] In the preset dynamic control output model, each grayscale control unit is used as a basic unit, a target output grayscale value is set for all target frequency modulation control points in the grayscale control unit, and the sum of the grayscale values ​​of all target frequency modulation control points in the grayscale control unit is set equal to a preset grayscale value sum threshold;

[0022] Based on the identified current printing paper type and the current dot standard parameters, the corresponding dot enlargement threshold is obtained; with each grayscale control unit as a basic unit, the dot enlargement value of all target frequency modulation control dots of each grayscale control unit is controlled to be less than or equal to the corresponding dot enlargement threshold.

[0023] By adopting the above technical scheme, a platemaking machine based on frequency modulation dot technology needs to select different dot enlargement thresholds due to the need to select different dot enlargement thresholds for different types of printing paper and dot standard parameters in the dot amplitude, dot shape and dot line number. In order to improve the precision and image quality of printed images and improve the product quality of printed images during color separation printing, the present application generates a plurality of grayscale control units in the screen type control adjustment area based on the target frequency modulation control dots, and associates and matches the corresponding dot enlargement thresholds based on the control parameters of each grayscale control unit; wherein the grayscale control unit is an area where the grayscale value and tone level of the dots change more obviously during the platemaking process, and is also an area where the number of dots of the target frequency modulation control dots of the printed image is large, or an area where the printed image has a large number of dots. The area where the expansion rate of the target frequency modulation control dots changes significantly is an area. In order to effectively ensure that the entire printed image outputs standard grayscale during the frequency modulation screen printing process, the present application uses a grayscale control unit as a basic unit. During the printing process, the total grayscale value of all target frequency modulation control dots in the grayscale control unit is controlled to be equal to a preset grayscale value total threshold, and the dot enlargement value of all target frequency modulation control dots of each grayscale control unit is controlled to be less than or equal to the corresponding dot enlargement threshold. The frequency modulation network technology is applied to make the dots reach the standard of the ideal dots as much as possible. The grayscale value on the printed image is correctly compensated through the control of the dot enlargement value, which can effectively ensure and improve the product quality during color separation printing.

[0024] In a preferred example of the present application, the preset grayscale value sum threshold includes a preset horizontal grayscale value and a preset vertical grayscale value; the target output grayscale value is set for all target frequency modulation control dots in the grayscale control unit, and the sum of the grayscale values ​​of all target frequency modulation control dots in the grayscale control unit is set to be equal to the preset grayscale value sum threshold, including:

[0025] Using a traversal method to set target output grayscale values ​​for all target frequency modulation control points in the grayscale control unit;

[0026] In the preset dynamic control output model, a first preset fixed number of multiple target frequency modulation control dots in the grayscale control unit is set, and the sum of the target output grayscale values ​​in the horizontal direction is equal to the preset horizontal total grayscale value; a second preset fixed number of multiple target frequency modulation control dots in the grayscale control unit is set, and the sum of the target output grayscale values ​​in the vertical direction is equal to the preset vertical total grayscale value.

[0027] By adopting the above technical solution, the output grayscale values ​​of all grayscale control units are finely controlled through dynamic control of grayscale values ​​in the horizontal and vertical directions combined with the traversal method, so that the grayscale values ​​on the printed image can be correctly compensated in the printing image process, which can effectively ensure and improve the product quality during color separation printing.

[0028] In a preferred example of the present application: the method further includes:

[0029] In different brightness gradation areas of the preprocessed target image, reference identification points and a plurality of calibration reference points are respectively set in one-to-one correspondence to obtain a reference identification grid pattern and corresponding theoretical grid pattern data based on the same brightness gradation area;

[0030] After triggering the plate-making printing control instruction according to the target dot grayscale level and the dot dynamic control parameter, the method further includes:

[0031] Based on the obtained printing plate halftone image that has been printed, the reference mark dot images and calibration reference dot images in different brightness gradation areas are obtained; based on the reference mark dot images and calibration reference dot images in the same brightness gradation area, the image quality evaluation result of the printing plate halftone image in each printing process is calculated with the corresponding reference mark network type and theoretical network type data as the reference;

[0032] Based on the image quality evaluation result, the laser power output value of different frequency modulation dots of the corresponding plate-making machine in the frequency modulation dot mode is corrected.

[0033] By adopting the above-mentioned technical scheme, in order to ensure standardization and repeatability in the printing production process, the present application adopts a dot distance calibration method of setting reference identification points and multiple calibration reference points in different brightness gradation zones, and calculates and determines the image quality evaluation result of the printing plate dot image of each printing process by setting the reference identification network type and theoretical network type data as calibration in multiple different brightness gradation zones, and then corrects the laser power output value of different frequency modulation dots of the corresponding platemaking machine in the frequency modulation dot mode based on the image quality evaluation result, and optimizes and adjusts the frequency modulation dots based on the actual equipment parameters of the platemaking machine by selecting appropriate random rate of dot hanging and laser beam diameter, so as to obtain a printed image with higher image reproduction quality and more convenient operation. Through the optimized application of frequency modulation Jiawang technology and the technical means of improving image reproduction accuracy, a printing production technology that can be replicated in batches is realized, which effectively ensures the standardization and repeatability of the production process of the platemaking machine.

[0034] In the second aspect, the invention objective of the present application is achieved by adopting the following technical solutions:

[0035] A system for improving the quality of printed images based on frequency modulation dots, the system comprising:

[0036] An image preprocessing module is used to perform image preprocessing on a target printing image to obtain a preprocessed target image;

[0037] The initial process parameter analysis module is used to obtain the initial process parameters based on the acquired platemaking machine equipment parameters and the platemaking standard information of each platemaking link in the platemaking process;

[0038] A dot standard parameter acquisition module, used for acquiring frequency modulation dots and corresponding dot standard parameters in different brightness gradation areas of the preprocessed target image based on the initial process parameters;

[0039] A dot dynamic control parameter acquisition module is used to acquire a historical printing grayscale image according to the plate-making machine equipment parameters, determine the device imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determine the target dot grayscale level and dot dynamic control parameters in combination with the frequency-modulated dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency-modulated dots;

[0040] The instruction control execution module is used to trigger the plate-making printing control instruction according to the target dot gray level and the dot dynamic control parameter.

[0041] By adopting the above technical solution, the target printing image is preprocessed by image processing software to obtain a preprocessed target image suitable for FM dot conversion, wherein the platemaking machine equipment parameters are the initial equipment parameters of the current platemaking machine equipment, and the platemaking standard information of each platemaking link is used to obtain the initial process parameters according to the process standard requirements corresponding to the current printing material and printing equipment characteristics, and the FM dots and corresponding dot standard parameters in different brightness gradation areas under the current platemaking machine equipment conditions are obtained through the initial process parameters, and the dot standard parameters are the dot parameters that meet the high standards of relevant printing image quality. In order to detect the platemaking and printing quality of the current platemaking machine, effectively improve the control accuracy of the platemaking machine, and improve the quality of printed images, the present application obtains historical printing grayscale images of the same platemaking machine equipment parameters to determine the equipment imaging characteristics and screen type control adjustment area based on the current platemaking machine, and the equipment imaging characteristics include The output linearization characteristics and dot shape characteristics of the equipment, the screen type control adjustment area is an unstable area of ​​the dot shape, and the screen type of this area needs to be adjusted; at this time, the target dot grayscale level and dot dynamic control parameters are determined in combination with the FM dots in different brightness gradation areas of the current platemaking machine equipment and the corresponding dot standard parameters, so as to determine the dot gradation area that needs to be adjusted, the corresponding dot position and the specific adjustment content, so as to achieve high-quality FM dot hanging effect based on different density areas and on the basis of the screen type formed by the existing FM dots, combined with the requirements of the dot shape of the printed image for the stability of the equipment output, and finely control the dot shape. By confirming the FM dots to be adjusted in advance and determining the adjustment content, it is helpful to reduce the problems of FM dot loss and plate blurring. Finally, according to the target dot grayscale level and dot dynamic control parameters, the platemaking printing control instructions are triggered, which is conducive to achieving the purpose of improving the quality of printed image reproduction.

[0042] In a preferred example of the present application: the network point dynamic control parameter acquisition module includes:

[0043] A historical printing grayscale image acquisition submodule, used for acquiring a historical printing grayscale image based on the platemaking machine equipment parameters, wherein the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the platemaking machine equipment parameters;

[0044] A plate-making machine equipment parameter analysis submodule, for determining dot shape information and a plurality of mesh density areas based on the historical printing grayscale image, and determining device imaging characteristics and mesh control adjustment areas corresponding to the plate-making machine equipment parameters in combination with device output stability and output linearization characteristics of the plate-making machine equipment parameters;

[0045] A target frequency modulation control dot determination submodule is used to obtain corresponding output grayscale level information based on the imaging characteristics of the device and the mesh type control adjustment area, and determine a number of target frequency modulation control dots among the frequency modulation dots in the different brightness gradation areas according to a preset output grayscale dynamic statistical algorithm;

[0046] The grayscale level and dynamic control parameter determination submodule is used to determine the target dot grayscale level and dot dynamic control parameters based on the device imaging characteristics of the platemaking machine equipment parameters, the screen type control adjustment area, a number of the target frequency modulation control dots and the corresponding dot standard parameters.

[0047] By adopting the above technical scheme, the dot shape information and several corresponding mesh density areas under the current FM dot mode are determined based on the historical printing grayscale image. The mesh density area is the area where the FM dots are densely distributed. The mesh density area is the area where the possibility of dot loss, plate blurring, etc. affecting the reproduction of printed image details is relatively high. It is the key analysis area that can provide feedback on the printing quality and image accuracy of the platemaking machine. Therefore, after determining the equipment imaging characteristics and mesh control adjustment area of ​​the corresponding platemaking machine equipment parameters, in order to obtain a printed image with higher image quality in the subsequent printing process, the present application determines the target dot grayscale level and dot dynamic control parameters based on the FM dot technology in the printing process by outputting a grayscale dynamic statistical algorithm, so as to achieve dynamic control of the printing accuracy of the FM dots and realize efficient adjustment of the FM network.

[0048] In the third aspect, the invention objective of this application is achieved by adopting the following technical solutions:

[0049] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for improving the quality of printed images based on frequency modulation dots are implemented.

[0050] In a fourth aspect, the invention objective of the present application is achieved by adopting the following technical solutions:

[0051] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for improving the quality of printed images based on frequency modulation dots are implemented.

[0052] In summary, the present application includes at least one of the following beneficial technical effects:

[0053] 1. Preprocess the target printing image through image processing software to obtain a preprocessed target image suitable for FM dot conversion, wherein the platemaking machine equipment parameters are the initial equipment parameters of the current platemaking machine equipment, and the platemaking standard information of each platemaking link is used to obtain the initial process parameters according to the process standard requirements corresponding to the current printing materials and printing equipment characteristics, and the FM dots and corresponding dot standard parameters in different brightness gradation areas under the current platemaking machine equipment conditions are obtained through the initial process parameters. The dot standard parameters are dot parameters that meet the high standards of relevant printing image quality requirements; in order to detect the platemaking and printing quality of the current platemaking machine, effectively improve the control accuracy of the platemaking machine, and improve the quality of printed images, this application obtains historical printing grayscale images of the same platemaking machine equipment parameters to determine the device imaging characteristics and screen type control adjustment area based on the current platemaking machine, and the device imaging characteristics include the output of the device Linearization characteristics and dot shape characteristics, the mesh type control adjustment area is an unstable area of ​​the dot shape, and the mesh type of this area needs to be adjusted; at this time, the target dot grayscale level and dot dynamic control parameters are determined in combination with the FM dots in different brightness gradation areas of the current platemaking machine equipment and the corresponding dot standard parameters to determine the dot gradation area that needs to be adjusted, the corresponding dot position and the specific adjustment content, so as to achieve high-quality FM dot hanging effect based on different density areas and on the basis of the mesh type formed by the existing FM dots, combined with the requirements of the dot shape of the printed image for the output stability of the equipment, and finely control the dot shape. By confirming the FM dots to be adjusted in advance and determining the adjustment content, it is helpful to reduce the problems of FM dot loss and plate smearing. Finally, according to the target dot grayscale level and dot dynamic control parameters, the platemaking printing control instruction is triggered, which is conducive to achieving the purpose of improving the reproduction quality of the printed image;

[0054] 2. Based on the historical printing grayscale image, determine the dot shape information and the corresponding several mesh density areas under the current FM dot mode. The mesh density area is the area where the FM dots are densely distributed. The mesh density area is the area where the possibility of dot loss, plate smudging, etc. that affect the reproduction of printed image details is relatively high. It is a key analysis area that can provide feedback on the printing quality and image accuracy of the platemaking machine. Therefore, after determining the device imaging characteristics and mesh control adjustment area of ​​the corresponding platemaking machine equipment parameters, in order to obtain a printed image with higher printing image quality in the subsequent printing process, this application determines the target dot grayscale level and dot dynamic control parameters based on the FM dot technology in the printing process by outputting a grayscale dynamic statistical algorithm, so as to achieve dynamic control of the printing accuracy of the FM dots and realize efficient adjustment of the FM network;

[0055] 3. In order to ensure standardization and repeatability in the printing production process, the present application adopts a dot distance calibration method of setting reference identification points and multiple calibration reference points in different brightness gradation zones. By setting the reference identification network type and theoretical network type data as calibration in multiple different brightness gradation zones, the image quality evaluation result of the printing plate dot image of each printing process is calculated and determined, and then based on the image quality evaluation result, the laser power output value of different frequency modulation dots of the corresponding platemaking machine in the frequency modulation dot mode is corrected. Based on the actual equipment parameters of the platemaking machine, the appropriate network dot hanging random rate and laser beam diameter are selected to optimize and adjust the frequency modulation dots to obtain a printed image with higher image reproduction quality and more convenient operation. Through the optimized application of the frequency modulation Jiawang technology and the technical means of improving the image reproduction accuracy, a printing production technology that can be replicated in batches is realized, which effectively ensures the standardization and repeatability of the production process of the platemaking machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a flow chart of a method for improving printed image quality based on frequency modulation dots in one embodiment of the present application;

[0057] Figure 2 is a flow chart of step S4 in a method for improving printed image quality based on frequency modulation dots in one embodiment of the present application;

[0058] Figure 3 It is a schematic diagram of a device in an embodiment of the present application. DETAILED DESCRIPTION

[0059] The present application is further described in detail below in conjunction with the accompanying drawings.

[0060] In one embodiment, if Figure 1 As shown, the present application discloses a method for improving the quality of printed images based on frequency modulation dots, which specifically includes the following steps:

[0061] S1: performing image preprocessing on a target printing image to obtain a preprocessed target image.

[0062] In this embodiment, the target printing image is the target plate-making image content of the plate-making machine; the target printing image is pre-processed using image processing software to obtain a pre-processed target image in the form of a digital file suitable for frequency modulation dot conversion.

[0063] S2: Based on the acquired platemaking machine equipment parameters and the platemaking standard information of each platemaking link in the platemaking process, the initial process parameters are obtained.

[0064] Specifically, the platemaking machine equipment parameters are the initial equipment parameters of the current platemaking machine equipment. The initial process parameters required by the process standards corresponding to the current printing materials and printing equipment characteristics are obtained through the platemaking machine equipment parameters and the platemaking standard information of each platemaking link.

[0065] S3: Acquire frequency modulation dots and corresponding dot standard parameters of different brightness gradation areas of the preprocessed target image based on the initial process parameters.

[0066] In this embodiment, different brightness tone areas include bright tone, middle tone and dark tone divided based on the gray value of the image; gray levels 0 to 25 and 230 to 255 are set as bright tone and dark tone respectively, and gray levels 25 to 230 are middle tone. The standard parameters of the dots are theoretical parameters of dots that meet the high standards of relevant printed image quality, and the standard parameters of the dots include dot line number information, dot shape, dot amplitude and dot enlargement threshold.

[0067] S4: Obtain historical printing grayscale images according to platemaking machine equipment parameters, determine device imaging characteristics and screen type control adjustment areas corresponding to platemaking machine equipment parameters based on the historical printing grayscale images, and determine target dot grayscale levels and dot dynamic control parameters in combination with frequency-modulated dots in different brightness gradation zones and corresponding dot standard parameters; dot dynamic control parameters include dot output range parameters based on frequency-modulated dots.

[0068] In this embodiment, the imaging characteristics of the device include the output linearization characteristics and dot shape characteristics of the device; the screen type control adjustment area is an unstable area of ​​the dot shape, and the screen type of this area needs to be adjusted; the dot dynamic control parameter is the corresponding dynamic parameter range of the control parameter of the frequency modulation dot when it meets the ideal dot standard requirements.

[0069] Specifically, in order to detect the plate-making printing quality of the current plate-making machine, effectively improve the control accuracy of the plate-making machine, and improve the quality of the printed image, the present application obtains the historical printing grayscale image of the same plate-making machine equipment parameters to determine the equipment imaging characteristics and mesh control adjustment area based on the current plate-making machine. Through the equipment imaging characteristics and mesh control adjustment area of ​​the current plate-making machine, combined with the frequency-modulated dots in different brightness gradation areas and the corresponding standard parameters of the dots, the target dot grayscale level and the dot dynamic control parameters are determined, so as to determine the dot gradation area that needs to be adjusted, the corresponding dot position and the specific adjustment content, so as to achieve a high-quality frequency-modulated dot hanging screen effect based on different density areas and on the basis of the mesh formed by the existing frequency-modulated dots, combined with the requirements of the device output stability on the dot shape of the printed image, and finely control the dot shape.

[0070] S5: triggering the plate-making and printing control instructions according to the target dot grayscale level and dot dynamic control parameters.

[0071] Specifically, the platemaking machine executes the platemaking printing operation based on the received platemaking printing control instructions. The present application predetermines the target dot grayscale level and dot dynamic control parameters to confirm the FM dots to be adjusted and determine the adjustment content in advance, which is beneficial to reduce the problems of FM dot loss and plate blurring. Finally, the platemaking printing control instructions are triggered according to the target dot grayscale level and dot dynamic control parameters, which is beneficial to achieve the purpose of improving the quality of printed image reproduction.

[0072] In one embodiment, if Figure 2 As shown, in step S4, a historical printing grayscale image is obtained according to the plate-making machine equipment parameters, and the device imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters are determined based on the historical printing grayscale image, and the target dot grayscale level and dot dynamic control parameters are determined in combination with the frequency modulation dots in different brightness gradation areas and the corresponding dot standard parameters, including:

[0073] S41: acquiring a historical printing grayscale image based on the plate-making machine equipment parameters, where the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the plate-making machine equipment parameters.

[0074] In this embodiment, the historical printing grayscale image is a reference grayscale image obtained by performing plate-making printing based on the current standard setting of plate-making machine process parameters.

[0075] Specifically, by performing image quality evaluation based on historical printing grayscale images, it is possible to obtain evaluation results of the output stability and image quality output of the current platemaking machine equipment, so as to analyze the characteristics of the platemaking machine equipment and the printing effect; the present application is based on the plate number repetition function of the current platemaking machine equipment parameters, and repeatedly outputs the frequency-modulated dots in different brightness gradation areas to obtain platemaking machine process parameter settings with better repeatability and batch replication consistency, so as to obtain platemaking machine equipment with higher printing image quality, and adaptively adjust the actual platemaking machine equipment parameters of different platemaking machines to improve the applicability of the software for improving the printing image quality based on frequency-modulated dots.

[0076] S42: Determine dot shape information and several mesh density areas based on historical printing grayscale images, and determine device imaging characteristics and mesh control adjustment areas corresponding to the platemaking machine equipment parameters in combination with device output stability and output linearization characteristics of the platemaking machine equipment parameters.

[0077] In this embodiment, the mesh density area is an area where FM dots are densely distributed. The mesh density area is an area where dot loss, plate blurring, and other factors that may affect the reproduction of printed image details are more likely to occur. It is a key analysis area that can provide feedback on the printing quality and image accuracy of the platemaking machine.

[0078] S43: Based on the imaging characteristics of the device and the screen type control adjustment area, the corresponding output grayscale level information is obtained, and according to a preset output grayscale dynamic statistical algorithm, a number of target frequency modulation control dots are determined in the frequency modulation dots in different brightness gradation areas.

[0079] In this embodiment, the output grayscale dynamic statistical algorithm is a grayscale value summing algorithm for a fixed rectangular area (such as a 3X3 rectangular area) based on the dot distribution area, and the total grayscale values ​​of multiple dots in the current row, two adjacent rows, current column and two adjacent columns of the current FM dot are counted. The output grayscale dynamic statistical algorithm is a dynamic summation method using a rolling window for summing.

[0080] S44: Determine the target dot grayscale level and dot dynamic control parameters based on the device imaging characteristics of the platemaking machine device parameters, the screen type control adjustment area, a number of target frequency modulation control dots and corresponding dot standard parameters.

[0081] Specifically, after determining the device imaging characteristics and screen control adjustment area of ​​the corresponding platemaking machine equipment parameters, in order to obtain a printed image with higher quality in the subsequent printing process, the present application determines the target dot grayscale level and dot dynamic control parameters based on the frequency modulation dot technology in the printing process by outputting a grayscale dynamic statistical algorithm, so as to achieve the printing accuracy of the dynamic control of the frequency modulation dots and realize the efficient adjustment of the frequency modulation network.

[0082] In one embodiment, the dot dynamic control parameter includes a dot enlargement threshold value set corresponding to different types of printing paper and dot standard parameters. After step S5, a method for improving the quality of printed images based on frequency modulation dots includes:

[0083] S51: Based on a plurality of target frequency modulation control dots, a plurality of grayscale control units are generated in a screen type control adjustment area.

[0084] Specifically, the grayscale control unit is an area where the grayscale value and tone level of the dots change more obviously during the platemaking process, an area where the number of target frequency modulation control dots of the printed image is relatively large, or an area where the expansion rate of the dot percentage of the target frequency modulation control dots of the printed image changes more obviously. As long as any of the above conditions is met, the grayscale control unit can be divided and generated in the screen type control adjustment area.

[0085] S52: In the preset dynamic control output model, each grayscale control unit is taken as a basic unit, and a target output grayscale value is set for all target frequency modulation control points in the grayscale control unit, and the sum of the grayscale values ​​of all target frequency modulation control points in the grayscale control unit is set equal to a preset grayscale value sum threshold.

[0086] In this embodiment, the dynamic control output model is constructed based on neural network recognition and deep learning models, and is an intelligent control model used to control the output grayscale values ​​of all target frequency modulation control dots in the printing process.

[0087] S53: Based on the identified current printing paper type and current dot standard parameters, a corresponding dot gain threshold is obtained; taking each grayscale control unit as a basic unit, the dot gain values ​​of all target frequency modulation control dots of each grayscale control unit are controlled to be less than or equal to the corresponding dot gain threshold.

[0088] In this embodiment, the dot gain threshold is a warning threshold designed accordingly based on the dot gain value of the dots. The specific value needs to be customized according to the current printing paper type and the current dot standard parameters, such as a dot gain threshold of 1%-4%.

[0089] Specifically, in order to effectively ensure that the entire printed image outputs standard grayscale with frequency modulation and screening during the printing process, the present application uses a grayscale control unit as a basic unit. During the printing process, the total grayscale values ​​of all target frequency modulation controlled dots in the grayscale control unit are controlled to be equal to a preset grayscale value total threshold, and the dot enlargement values ​​of all target frequency modulation controlled dots of each grayscale control unit are controlled to be less than or equal to the corresponding dot enlargement threshold. The frequency modulation network technology is applied to make the dots reach the standard of ideal dots as much as possible. The grayscale values ​​on the printed image are correctly compensated through the control of the dot enlargement value, which can effectively ensure and improve the product quality during color separation printing.

[0090] In one embodiment, the preset gray value sum threshold includes a preset horizontal gray value and a preset vertical gray value; in step S52, setting a target output gray value for all target frequency modulation control dots in the gray control unit, and setting the gray value sum of all target frequency modulation control dots in the gray control unit to be equal to the preset gray value sum threshold, including:

[0091] S521: Using the traversal method to set the target output grayscale value for all the target frequency modulation control points in the grayscale control unit.

[0092] Specifically, after setting the target output grayscale values ​​for all the target frequency modulation control dots in the grayscale control unit, the platemaking machine performs the platemaking printing operation based on the received platemaking printing control instruction.

[0093] S522: In a preset dynamic control output model, a first preset fixed number of multiple target frequency modulation control dots are set in the grayscale control unit, and the sum of the target output grayscale values ​​in the horizontal direction is equal to the preset total grayscale value in the horizontal direction; a second preset fixed number of multiple target frequency modulation control dots are set in the grayscale control unit, and the sum of the target output grayscale values ​​in the vertical direction is equal to the preset total grayscale value in the vertical direction.

[0094] In this embodiment, the first preset fixed number and the second preset fixed number are both 3, and the specific number can be customized as needed.

[0095] Specifically, the grayscale values ​​in the horizontal and vertical directions are dynamically controlled in combination with the traversal method to finely control the output grayscale values ​​of all grayscale control units, so that the grayscale values ​​on the printed image can be correctly compensated in the printing image process, which can effectively ensure and improve the product quality during color separation printing.

[0096] In one embodiment, a method for improving printed image quality based on frequency modulation dots further includes:

[0097] S100: setting reference identification points and a plurality of calibration reference points in a one-to-one correspondence in different brightness gradation areas of the preprocessed target image, and obtaining a reference identification grid pattern and corresponding theoretical grid pattern data based on the same brightness gradation area.

[0098] In this embodiment, the reference identification grid is a dot grid formed by multiple dots that are accurately reproduced in the brightness gradation area in accordance with the standardized process parameter requirements; the theoretical grid data includes shape data, amplitude data and dot line quantity data of multiple dots in the grid.

[0099] Specifically, in order to ensure standardization and repeatability in the printing production process, the present application adopts a dot distance calibration method that sets reference identification points and multiple calibration reference points in different brightness gradation zones. By setting reference identification screen patterns and theoretical screen pattern data for calibration in multiple different brightness gradation zones, the image quality evaluation results of the printing plate dot image of each printing process are calculated and determined.

[0100] After triggering the plate-making printing control instruction according to the target dot grayscale level and dot dynamic control parameters, the following steps are also included:

[0101] S501: Based on the obtained printing plate dot image that has been printed, obtain the benchmark identification dot images and calibration reference dot images in different brightness gradation areas; based on the benchmark identification dot images and calibration reference dot images in the same brightness gradation area, take the corresponding benchmark identification network type and theoretical network type data as the reference, calculate the image quality evaluation result of the printing plate dot image of each printing process.

[0102] S502: Correcting the laser power output values ​​of different frequency modulation dots of the corresponding plate-making machine in the frequency modulation dot mode based on the image quality evaluation result.

[0103] In this embodiment, the laser power output value includes the dot laser power and the laser beam diameter. In actual application, the dot randomness rate of different frequency-modulated dots in the frequency-modulated dot mode of the corresponding platemaking machine will be corrected based on the image quality evaluation result, so that the printing quality of the platemaking machine's production is further improved.

[0104] Specifically, based on the image quality evaluation results, the laser power output values ​​of different FM dots of the corresponding platemaking machine in the FM dot mode are corrected, and based on the actual equipment parameters of the platemaking machine, the FM dots are optimized and adjusted by selecting appropriate dot hanging random rate and laser beam diameter to obtain a printed image with higher image reproduction quality and more convenient operation. Through the optimized application of FM Jiawang technology and the technical means of improving image reproduction accuracy, a batch-replicable printing production technology is realized, which effectively ensures the standardization and repeatability of the production process of the platemaking machine.

[0105] It should be understood that the serial numbers of the steps in the above embodiments do not imply a sequence of execution. The execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0106] In one embodiment, a system for improving printed image quality based on frequency modulation dots is provided, and the system for improving printed image quality based on frequency modulation dots corresponds to the method for improving printed image quality based on frequency modulation dots in the above embodiment.

[0107] A system for improving the quality of printed images based on frequency modulation dots includes an image preprocessing module, an initial process parameter analysis module, a dot standard parameter acquisition module, a dot dynamic control parameter acquisition module, and an instruction control execution module. The detailed description of each functional module is as follows:

[0108] An image preprocessing module is used to perform image preprocessing on a target printing image to obtain a preprocessed target image;

[0109] The initial process parameter analysis module is used to obtain the initial process parameters based on the acquired platemaking machine equipment parameters and the platemaking standard information of each platemaking link in the platemaking process;

[0110] A dot standard parameter acquisition module, used for acquiring frequency modulation dots and corresponding dot standard parameters of different brightness gradation areas of a preprocessed target image based on the initial process parameters;

[0111] A dot dynamic control parameter acquisition module is used to acquire a historical printing grayscale image according to the plate-making machine equipment parameters, determine the device imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determine the target dot grayscale level and dot dynamic control parameters in combination with the frequency-modulated dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency-modulated dots;

[0112] The instruction control execution module is used to trigger the plate-making printing control instruction according to the target dot gray level and dot dynamic control parameters.

[0113] Optionally, the network point dynamic control parameter acquisition module includes:

[0114] A historical printing grayscale image acquisition submodule is used to acquire a historical printing grayscale image based on the platemaking machine equipment parameters, and the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the platemaking machine equipment parameters;

[0115] The plate-making machine equipment parameter analysis submodule is used to determine the dot shape information and several mesh density areas based on the historical printing grayscale image, and determine the equipment imaging characteristics and mesh control adjustment area corresponding to the plate-making machine equipment parameters in combination with the equipment output stability and output linearization characteristics of the plate-making machine equipment parameters;

[0116] The target frequency modulation control dot determination submodule is used to obtain the corresponding output grayscale level information based on the device imaging characteristics and the mesh type control adjustment area, and determine a number of target frequency modulation control dots in the frequency modulation dots in different brightness gradation areas according to the preset output grayscale dynamic statistical algorithm;

[0117] The grayscale level and dynamic control parameter determination submodule is used to determine the target dot grayscale level and dot dynamic control parameters based on the device imaging characteristics of the platemaking machine equipment parameters, the screen type control adjustment area, a number of target frequency modulation control dots and the corresponding dot standard parameters.

[0118] Regarding the specific definition of a system for improving printed image quality based on frequency modulation dots, please refer to the definition of a method for improving printed image quality based on frequency modulation dots in the above text, which will not be repeated here; each module in the above-mentioned system for improving printed image quality based on frequency modulation dots can be fully or partially implemented by software, hardware and their combination; each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0119] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 3 As shown. The computer device includes a processor, a memory, a network interface and a database connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store standard parameters of dots, historical printing grayscale images, target dot grayscale levels and dot dynamic control parameters, etc. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for improving the quality of printed images based on frequency modulation dots is implemented.

[0120] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0121] S1: performing image preprocessing on a target printing image to obtain a preprocessed target image;

[0122] S2: based on the acquired plate-making machine equipment parameters and the plate-making standard information of each plate-making link in the plate-making process, the initial process parameters are obtained;

[0123] S3: obtaining frequency modulation dots and corresponding dot standard parameters in different brightness gradation areas of the preprocessed target image based on the initial process parameters;

[0124] S4: acquiring a historical printing grayscale image according to the plate-making machine equipment parameters, determining the equipment imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determining the target dot grayscale level and dot dynamic control parameters in combination with the frequency modulation dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency modulation dots;

[0125] S5: triggering the plate-making and printing control instructions according to the target dot grayscale level and dot dynamic control parameters.

[0126] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0127] S1: performing image preprocessing on a target printing image to obtain a preprocessed target image;

[0128] S2: based on the acquired plate-making machine equipment parameters and the plate-making standard information of each plate-making link in the plate-making process, the initial process parameters are obtained;

[0129] S3: obtaining frequency modulation dots and corresponding dot standard parameters in different brightness gradation areas of the preprocessed target image based on the initial process parameters;

[0130] S4: acquiring a historical printing grayscale image according to the plate-making machine equipment parameters, determining the equipment imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determining the target dot grayscale level and dot dynamic control parameters in combination with the frequency modulation dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency modulation dots;

[0131] S5: triggering the plate-making and printing control instructions according to the target dot grayscale level and dot dynamic control parameters.

[0132] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0133] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0134] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some of the features thereof may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for improving the quality of printed images based on frequency modulation dots, characterized in that: include: Performing image preprocessing on the target printing image to obtain a preprocessed target image; Based on the acquired plate-making machine equipment parameters and the plate-making standard information of each plate-making link in the plate-making process, the initial process parameters are obtained; Acquire frequency modulation dots and corresponding dot standard parameters in different brightness gradation areas of the preprocessed target image based on the initial process parameters; Acquire a historical printing grayscale image according to the plate-making machine equipment parameters, determine the equipment imaging characteristics and screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determine the target dot grayscale level and dot dynamic control parameters in combination with the frequency-modulated dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency-modulated dots; Triggering a plate-making printing control instruction according to the target dot grayscale level and the dot dynamic control parameter; The method of acquiring a historical printing grayscale image according to the plate-making machine equipment parameters, determining the equipment imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determining the target dot grayscale level and dot dynamic control parameters in combination with the frequency modulation dots in different brightness gradation areas and the corresponding dot standard parameters, includes: Acquire a historical printing grayscale image based on the plate-making machine equipment parameters, wherein the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the plate-making machine equipment parameters; Determine dot shape information and a plurality of mesh density areas based on the historical printing grayscale image, and determine device imaging characteristics and mesh control adjustment areas corresponding to the platemaking machine equipment parameters in combination with device output stability and output linearization characteristics of the platemaking machine equipment parameters; Based on the imaging characteristics of the device and the screen type control adjustment area, the corresponding output grayscale level information is obtained, and according to a preset output grayscale dynamic statistical algorithm, a number of target frequency modulation control dots are determined in the frequency modulation dots in the different brightness gradation areas; Based on the device imaging characteristics of the platemaking machine device parameters, the screen type control adjustment area, a number of the target frequency modulation control dots and the corresponding dot standard parameters, the target dot grayscale level and dot dynamic control parameters are determined.

2. The method for improving the quality of printed images based on frequency modulation dots according to claim 1, characterized in that: The dot dynamic control parameters include dot enlargement thresholds set corresponding to different types of printing paper and dot standard parameters; after triggering the plate-making printing control instruction according to the target dot grayscale level and the dot dynamic control parameters, the method includes: Based on the target frequency modulation control dots, generating a plurality of grayscale control units in the mesh control adjustment area; In the preset dynamic control output model, each grayscale control unit is used as a basic unit, a target output grayscale value is set for all target frequency modulation control points in the grayscale control unit, and the sum of the grayscale values ​​of all target frequency modulation control points in the grayscale control unit is set equal to a preset grayscale value sum threshold; Based on the identified current printing paper type and the current dot standard parameters, the corresponding dot enlargement threshold is obtained; with each grayscale control unit as a basic unit, the dot enlargement value of all target frequency modulation control dots of each grayscale control unit is controlled to be less than or equal to the corresponding dot enlargement threshold.

3. The method for improving the quality of printed images based on frequency modulation dots according to claim 2, characterized in that: The preset gray value sum threshold includes a preset horizontal gray value and a preset vertical gray value; the step of setting a target output gray value for all target frequency modulation control dots in the gray control unit and setting the gray value sum of all target frequency modulation control dots in the gray control unit to be equal to the preset gray value sum threshold includes: Using a traversal method to set target output grayscale values ​​for all target frequency modulation control points in the grayscale control unit; In the preset dynamic control output model, a first preset fixed number of multiple target frequency modulation control dots in the grayscale control unit is set, and the sum of the target output grayscale values ​​in the horizontal direction is equal to the preset horizontal total grayscale value; a second preset fixed number of multiple target frequency modulation control dots in the grayscale control unit is set, and the sum of the target output grayscale values ​​in the vertical direction is equal to the preset vertical total grayscale value.

4. The method for improving the quality of printed images based on frequency modulation dots according to claim 2, characterized in that: The method further comprises: In different brightness gradation areas of the preprocessed target image, reference identification points and a plurality of calibration reference points are respectively set in one-to-one correspondence to obtain a reference identification grid pattern and corresponding theoretical grid pattern data based on the same brightness gradation area; After triggering the plate-making printing control instruction according to the target dot grayscale level and the dot dynamic control parameter, the method further includes: Based on the obtained printing plate halftone image that has been printed, the reference mark dot images and calibration reference dot images in different brightness gradation areas are obtained; based on the reference mark dot images and calibration reference dot images in the same brightness gradation area, the image quality evaluation result of the printing plate halftone image in each printing process is calculated with the corresponding reference mark network type and theoretical network type data as the reference; Based on the image quality evaluation result, the laser power output value of different frequency modulation dots of the corresponding plate-making machine in the frequency modulation dot mode is corrected.

5. A system for improving the quality of printed images based on frequency modulation dots, characterized in that: The system comprises: An image preprocessing module is used to perform image preprocessing on a target printing image to obtain a preprocessed target image; The initial process parameter analysis module is used to obtain the initial process parameters based on the acquired platemaking machine equipment parameters and the platemaking standard information of each platemaking link in the platemaking process; A dot standard parameter acquisition module, used for acquiring frequency modulation dots and corresponding dot standard parameters in different brightness gradation areas of the preprocessed target image based on the initial process parameters; A dot dynamic control parameter acquisition module is used to acquire a historical printing grayscale image according to the plate-making machine equipment parameters, determine the device imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determine the target dot grayscale level and dot dynamic control parameters in combination with the frequency-modulated dots in different brightness gradation areas and the corresponding dot standard parameters; the dot dynamic control parameters include dot output range parameters based on the frequency-modulated dots; An instruction control execution module, used for triggering a plate-making printing control instruction according to the target dot grayscale level and the dot dynamic control parameter; The method of acquiring a historical printing grayscale image according to the plate-making machine equipment parameters, determining the equipment imaging characteristics and the screen type control adjustment area corresponding to the plate-making machine equipment parameters based on the historical printing grayscale image, and determining the target dot grayscale level and dot dynamic control parameters in combination with the frequency modulation dots in different brightness gradation areas and the corresponding dot standard parameters, includes: Acquire a historical printing grayscale image based on the plate-making machine equipment parameters, wherein the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the plate-making machine equipment parameters; Determine dot shape information and a plurality of mesh density areas based on the historical printing grayscale image, and determine device imaging characteristics and mesh control adjustment areas corresponding to the platemaking machine equipment parameters in combination with device output stability and output linearization characteristics of the platemaking machine equipment parameters; Based on the imaging characteristics of the device and the screen type control adjustment area, the corresponding output grayscale level information is obtained, and according to a preset output grayscale dynamic statistical algorithm, a number of target frequency modulation control dots are determined in the frequency modulation dots in the different brightness gradation areas; Based on the device imaging characteristics of the platemaking machine device parameters, the screen type control adjustment area, a number of the target frequency modulation control dots and the corresponding dot standard parameters, the target dot grayscale level and dot dynamic control parameters are determined.

6. The system for improving printed image quality based on frequency modulation dots according to claim 5, characterized in that: The network point dynamic control parameter acquisition module includes: A historical printing grayscale image acquisition submodule, used for acquiring a historical printing grayscale image based on the platemaking machine equipment parameters, wherein the historical printing grayscale image meets the conditions of the equipment pulse width modulation technical parameter standard corresponding to the platemaking machine equipment parameters; A plate-making machine equipment parameter analysis submodule, for determining dot shape information and a plurality of mesh density areas based on the historical printing grayscale image, and determining device imaging characteristics and mesh control adjustment areas corresponding to the plate-making machine equipment parameters in combination with device output stability and output linearization characteristics of the plate-making machine equipment parameters; A target frequency modulation control dot determination submodule is used to obtain corresponding output grayscale level information based on the imaging characteristics of the device and the mesh type control adjustment area, and determine a number of target frequency modulation control dots among the frequency modulation dots in the different brightness gradation areas according to a preset output grayscale dynamic statistical algorithm; The grayscale level and dynamic control parameter determination submodule is used to determine the target dot grayscale level and dot dynamic control parameters based on the device imaging characteristics of the platemaking machine equipment parameters, the screen type control adjustment area, a number of the target frequency modulation control dots and the corresponding dot standard parameters.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for improving the quality of printed images based on frequency modulation dots as described in any one of claims 1 to 4 are implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of a method for improving the quality of printed images based on frequency modulation dots as claimed in any one of claims 1 to 4 are implemented.

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