A method, device, equipment and medium for dynamically adjusting the printing color difference of a printer

Abstract

The present invention discloses a method, device, equipment and medium for dynamically adjusting the printing color difference of a printer, which relates to the technical field of industrial inkjet printing control software, and aims to solve the problems of high labor intensity and high requirements for equipment performance in the existing printing color difference adjustment methods. The method includes converting the acquired RGB image collected by the vision system into a first CMYK format image; comparing the first CMYK format image with a second CMYK format image to obtain the gray scale adjustment values of each gray scale adjustment area of the image; according to the gray scale adjustment values of each gray scale adjustment area of the image, using the Poisson disk sampling algorithm to perform dot layout adjustment of corresponding density on the second CMYK format image to obtain an adjusted CMYK format image; printing according to the adjusted CMYK format image to obtain a target printed image. The method, device, equipment and medium for dynamically adjusting the printing color difference of a printer provided by the present invention are used to reduce labor intensity and reduce the requirements for equipment performance.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial inkjet printing control software, and particularly to a method, device, equipment and medium for dynamically adjusting the printing color difference of a printer. Background Art

[0002] Color difference refers to the difference between the printed color and the color in the original image or design draft. Through precise color difference adjustment, the color of the printed product can be ensured to be highly consistent with the expectation, thereby improving the overall printing quality. There are mainly two methods for existing inkjet printers to adjust the printing color difference. One is to adjust the voltage of the print head. The disadvantage is that the relationship between the print head voltage and the color gray level is not linear, and the adjustment requires manual comparison multiple times, with a large labor intensity. The other is to make adjustments at the image RIP (Raster Image Processor) stage, that is, the print gray level adjustment parameters are fed back to the front end of the RIP. The disadvantages are that the RIP system does not have the layout information of the inkjet printer, it is difficult to accurately correspond to the corresponding position of the print head, and when the printing position is adjusted, it is necessary to re-check the adjustment range of the RIP, which is very inconvenient to use. At the same time, the RIP needs to reprocess the image, and the equipment performance requirements are high. Summary of the Invention

[0003] The purpose of the present invention is to provide a method, device, equipment and medium for dynamically adjusting the printing color difference of a printer, which is used to solve the problems of large labor intensity in the existing printing color difference adjustment method, the inability to accurately correspond the printed image information to the print head position, the need to re-check the RIP adjustment range, inconvenient use, and high equipment performance requirements.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] In the first aspect, the present invention provides a method for dynamically adjusting the printing color difference of a printer, including:

[0006] Obtain the RGB image collected by the vision system and convert the RGB image into a first CMYK format image;

[0007] Compare the first CMYK format image with the second CMYK format image to obtain the gray level adjustment values of each gray level adjustment area of the image;

[0008] According to the gray level adjustment values of each gray level adjustment area of the image, use the Poisson disk sampling algorithm to perform dot distribution adjustment with corresponding density on the second CMYK format image to obtain an adjusted CMYK format image;

[0009] Perform printing according to the adjusted CMYK format image to obtain a target printed image.

[0010] Compared with the prior art, a method for dynamically adjusting the printing color difference of a printer provided by the present invention converts the obtained RGB image into a first CMYK format image; compares the first CMYK format image with a second CMYK format image to obtain the gray-scale adjustment values of each gray-scale adjustment area of the image; according to the gray-scale adjustment values of each gray-scale adjustment area of the image, uses the Poisson disk sampling algorithm to perform dot layout adjustment of corresponding density on the second CMYK format image to obtain an adjusted CMYK format image; in this solution, due to the use of the Poisson disk sampling algorithm, the gray-scale adjustment of the CMYK format image can be directly performed according to the gray-scale adjustment value, so that the gray-scale adjustment value can be directly fed back to the back end of the RIP, that is, the printing engine, and the printing engine can directly print the adjusted CMYK format image without a series of processes of the RIP, reducing the performance requirements of the device, and also avoiding the problem of inconvenient use that requires re-checking the adjustment range of the RIP after adjusting the printing position. At the same time, since the printing engine retains the information of the actual corresponding nozzles and nozzle holes of each pixel of the image when processing the second CMYK image obtained after the first RIP processing, the adjusted CMYK format image data obtained by performing dot layout adjustment of corresponding density on the second CMYK format image according to the gray-scale adjustment value fed back to the printing engine can correspond to the printer layout. In addition, the Poisson disk sampling algorithm is used to adjust the image, ensuring the uniformity of dot layout and conforming to the human eye characteristics. The algorithm has a linear relationship with the gray scale and can be linearly adjusted, and the system response is fast.

[0011] Optionally, the step of using the Poisson disk sampling algorithm to perform dot layout adjustment of corresponding density on the second CMYK format image according to the gray-scale adjustment values of each gray-scale adjustment area of the image to obtain an adjusted CMYK format image includes:

[0012] Calculating the target percentage of the gray-scale adjustment value in the gray-scale value of the gray-scale adjustment area of the second CMYK format image;

[0013] Using the Poisson disk sampling algorithm to determine the target pixel dot layout diagram corresponding to the target percentage;

[0014] Adjusting the pixel dot density of the gray-scale adjustment area in the second CMYK format image according to the target pixel dot layout diagram, so that the pixel dot density of the adjusted gray-scale adjustment area increases or decreases by the target percentage compared with that before adjustment, to obtain an adjusted CMYK format image.

[0015] Optionally, the step of using the Poisson disk sampling algorithm to determine the target pixel dot layout diagram corresponding to the target percentage includes:

[0016] Substituting the target percentage into

[0017] sampleCount = width × height × M

[0018] Calculate the target sample quantity; where sampleCount is the target sample quantity, width is the width of the target pixel point layout diagram, height is the height of the target pixel point layout diagram, and M is the target percentage;

[0019] Substitute the target sample quantity into

[0020] minDistance = sqrt(width × height / sampleCount)

[0021] Obtain the minimum radius;

[0022] Randomly select pixel point samples that meet the preset conditions in the initial pixel point layout diagram according to the minimum radius to obtain the target pixel point layout diagram corresponding to the target percentage.

[0023] Optionally, the randomly selecting pixel point samples that meet the preset conditions in the initial pixel point layout diagram according to the minimum radius to obtain the target pixel point layout diagram corresponding to the target percentage includes:

[0024] Randomly generate an initial pixel point in the initial pixel point layout diagram, and save the initial pixel point into a random array;

[0025] Randomly generate N pixel points on a ring with the initial pixel point as the center, the minimum radius as the inner diameter, and the maximum radius as the outer diameter, where N is a positive integer, and the maximum radius is 2 times the minimum radius;

[0026] Check each of the N pixel points one by one, and save the pixel points whose distances from all the generated pixel points are greater than or equal to the minimum radius into the random array;

[0027] Continue sampling with a pixel point randomly selected from the random array until there are no pixel points that meet the preset conditions in the initial pixel point layout diagram to obtain the target pixel point layout diagram corresponding to the target percentage.

[0028] Optionally, the adjusting the pixel point density of the gray-scale adjustment area in the second CMYK format image according to the target pixel point layout diagram so that the pixel point density of the adjusted gray-scale adjustment area is increased or decreased by the target percentage compared with that before adjustment to obtain the adjusted CMYK format image includes:

[0029] If the pixel density of the adjusted grayscale adjustment area increases by the target percentage compared to before adjustment, then superimpose the target pixel layout map on the grayscale adjustment area so that the pixels in the target pixel layout map do not overlap with the pixels in the grayscale adjustment area, to obtain the addition positions of the pixels in the target pixel layout map in the grayscale adjustment area of the second CMYK format image, and add pixels at the addition positions to obtain the adjusted CMYK format image;

[0030] If the pixel density of the adjusted grayscale adjustment area decreases by the target percentage compared to before adjustment, then superimpose the target pixel layout map on the grayscale adjustment area so that the pixels in the target pixel layout map overlap with the pixels in the grayscale adjustment area, to obtain the deletion positions of the pixels in the target pixel layout map in the grayscale adjustment area of the second CMYK format image, and delete pixels at the deletion positions to obtain the adjusted CMYK format image.

[0031] Optionally, the comparing the first CMYK format image with the second CMYK format image to obtain the grayscale adjustment values of the grayscale adjustment areas of the image includes:

[0032] Calculate the difference between the first grayscale value of the pixels in the first CMYK format image and the second grayscale value of the corresponding pixels in the second CMYK format image;

[0033] Determine the initial grayscale adjustment value of the grayscale adjustment area according to the difference; if the first grayscale value is greater than the second grayscale value, then the initial grayscale adjustment value is to reduce the difference, and if the first grayscale value is less than the second grayscale value, then the initial grayscale adjustment value is to increase the difference;

[0034] Perform a fuzzy operation on the initial grayscale adjustment value of the grayscale adjustment area to obtain the target grayscale adjustment value of the grayscale adjustment areas of the image.

[0035] Optionally, after determining the target pixel layout map corresponding to the target percentage by using the Poisson disk sampling algorithm, it further includes:

[0036] Generate image blocks corresponding to the grayscales of each target percentage according to the target pixel layout map;

[0037] Save the image blocks corresponding to the grayscales of each target percentage as a lookup table;

[0038] Extract the corresponding image block from the lookup table according to the target percentage to be adjusted in the grayscale adjustment area of the second CMYK format image;

[0039] Adjust the pixel density of the gray-scale adjustment area in the second CMYK format image according to the extracted image blocks, so that the pixel density of the adjusted gray-scale adjustment area increases or decreases by the target percentage compared with that before adjustment, and obtain the adjusted CMYK format image.

[0040] In a second aspect, the present invention provides a device for dynamically adjusting the printing color difference of a printer, including:

[0041] An RGB image acquisition module, configured to acquire an RGB image collected by a vision system and convert the RGB image into a first CMYK format image;

[0042] A gray-scale adjustment value determination module, configured to compare the first CMYK format image with the second CMYK format image to obtain the gray-scale adjustment values of the gray-scale adjustment areas of the image;

[0043] A CMYK format image adjustment module, configured to perform dot layout adjustment with corresponding densities on the second CMYK format image according to the gray-scale adjustment values of the gray-scale adjustment areas of the image by using a Poisson disk sampling algorithm, and obtain the adjusted CMYK format image;

[0044] A printing module after the color difference adjustment is completed, configured to perform printing according to the adjusted CMYK format image to obtain a target printed image.

[0045] In a third aspect, the present invention provides a device for dynamically adjusting the printing color difference of a printer, including:

[0046] A communication unit / communication interface, configured to acquire an RGB image collected by a vision system and convert the RGB image into a first CMYK format image;

[0047] A processing unit / processor, configured to compare the first CMYK format image with the second CMYK format image to obtain the gray-scale adjustment values of the gray-scale adjustment areas of the image;

[0048] According to the gray-scale adjustment values of the gray-scale adjustment areas of the image, perform dot layout adjustment with corresponding densities on the second CMYK format image by using a Poisson disk sampling algorithm, and obtain the adjusted CMYK format image;

[0049] Perform printing according to the adjusted CMYK format image to obtain a target printed image.

[0050] In a fourth aspect, the present invention provides a computer-readable storage medium, in which instructions are stored, and when the instructions are run, the method for dynamically adjusting the printing color difference of a printer is implemented.

[0051] The technical effects achieved by the device - related solutions provided in the second aspect, the equipment - related solutions provided in the third aspect, and the computer - readable storage medium solutions provided in the fourth aspect are the same as those of the method - related solutions provided in the first aspect, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0053] Figure 1 It is a schematic diagram of the dynamic feedback process for adjusting the printing color difference of a printer provided by the present invention;

[0054] Figure 2 It is a flowchart of a method for dynamically adjusting the printing color difference of a printer provided by the present invention;

[0055] Figure 3 It is a schematic structural diagram of a device for dynamically adjusting the printing color difference of a printer provided by the present invention;

[0056] Figure 4 It is a schematic structural diagram of an equipment for dynamically adjusting the printing color difference of a printer provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and roles. For example, the first threshold and the second threshold are only used to distinguish different thresholds and do not limit their sequence. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order, and "first" and "second" do not necessarily mean different.

[0058] It should be noted that in the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0059] In the present invention, "at least one" means one or more, and "a plurality of" means two or more. "And / or" describes the relationship between associated objects and indicates that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates an "or" relationship between the associated objects before and after. "At least one (item)" or a similar expression refers to any combination of these items, including any combination of a single item or multiple items. For example, at least one (item) of a, b, or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b, and c, where a, b, and c can be single or multiple.

[0060] In the existing steps for adjusting the printing color difference of an inkjet printer, generally, the original image is processed by a raster image processor, and the processed data is sent to the printing engine. The printing engine prints according to the received data, determines the printing gray-scale adjustment parameters based on the printed image, and then sends the printing gray-scale adjustment parameters to the front end of the raster image processor. The printing gray-scale adjustment parameters are generally parameters for the RGB format. The raster image processor adjusts the RGB image according to the printing gray-scale adjustment parameters, and then performs a series of processes on the adjusted RGB image to obtain CMYK format data and send it to the printing engine for printing. By repeating the above steps, the printing color difference is finally adjusted. Since the raster image processor not only needs to convert the RGB image into a CMYK format image but also needs to complete color space conversion, halftone processing, gray balance, and color correction, and the amount of calculation involved in interpretation and screening is very large. Therefore, if the printing gray-scale adjustment parameters are sent to the front end of the raster image processor, it means that these processes need to be performed on the image again for each adjustment, and the requirements for device performance will be very high. In addition, there is no inkjet printer layout information in the raster image processor system, and it is difficult to accurately correspond the data of each area of the image to the corresponding position of the nozzle when adjusting the image according to the printing gray-scale adjustment parameters. Moreover, when the printing position is adjusted, it is necessary to recheck the adjustment range of the raster image processor, which is very inconvenient to use.

[0061] To solve the above problems, the present application provides a method, device, equipment, and medium for dynamically adjusting the printing color difference of a printer, as Figure 1As shown in the figure, the dynamic feedback process for adjusting the printing color difference is as follows: After the raster image processor (RIP) processes the original image, a CMYK format image is obtained. The printing engine processes the data of the CMYK format image and performs printing. The machine vision system captures the printed image, converts the captured image into a CMYK format image, and calculates the difference in grayscale values between the converted CMYK format image and the original CMYK format image to obtain the grayscale adjustment parameter. The grayscale adjustment parameter is fed back to the back end of the RIP, that is, the printing engine. Feeding back to the back end of the RIP eliminates the need for the RIP to process the image again, reducing the requirements for device performance. At the same time, since the grayscale adjustment parameter is directly sent to the printing engine, and the printing engine retains information about the actual corresponding nozzles, i.e., orifices, of each pixel when processing the original CMYK format image data, the printing engine can directly adjust the data of the CMYK format image based on the grayscale adjustment parameter in correspondence with the printer layout, and adjusting the printing position has no impact on the algorithm. Adjusting the data of the CMYK format image based on the grayscale adjustment parameter uses the Poisson disk sampling algorithm to increase or decrease points in the grayscale adjustment area, ensuring the uniformity of the point distribution and conforming to the characteristics of the human eye. In addition, the Poisson disk sampling algorithm has a linear relationship with the grayscale and can be linearly adjusted, with a fast system response. Next, an explanation will be given in conjunction with the accompanying drawings.

[0062] Figure 2 The following is a flowchart of a method for dynamically adjusting the printing color difference of a printer provided by the present invention. As Figure 2 shown, the method for dynamically adjusting the printing color difference of a printer includes the following steps:

[0063] Step 201: Obtain the RGB image captured by the vision system and convert the RGB image into a first CMYK format image;

[0064] The RGB image captured by the vision system is obtained by the vision system capturing the printed image obtained after the inkjet printer prints the original image.

[0065] As an optional method, the conversion of the RGB format image to the CMYK format image mainly involves two steps: the conversion from the RGB color model to the CMY color model and the conversion from the CMY color model to the CMYK color model. Specifically, converting the RGB image into the first CMYK format image includes:

[0066] Substitute the RGB data of the RGB image into formulas (1)-(3):

[0067] C1 = 1 - R / 255 (1)

[0068] M1 = 1 - G / 255 (2)

[0069] Y1 = 1 - B / 255 (3)

[0070] Calculate the grayscale values of each channel in the CMY model;

[0071] Wherein, R is the grayscale value of the red channel in the RGB image, G is the grayscale value of the green channel in the RGB image, B is the grayscale value of the blue channel in the RGB image; C1 is the grayscale value of the cyan channel in the CMY model, M1 is the grayscale value of the magenta channel in the CMY model; Y1 is the grayscale value of the yellow channel in the CMY model;

[0072] Substitute the grayscale values of each channel in the CMY model into formulas (4)-(7):

[0073] K = min(C, M, Y) (4)

[0074] C = (C1 - K) / (1 - K) (5)

[0075] M = (M1 - K) / (1 - K) (6)

[0076] Y = (Y1 - K) / (1 - K) (7)

[0077] Calculate the grayscale values of each channel in the CMYK model to obtain the first CMYK format image;

[0078] Wherein, C is the grayscale value of the cyan channel in the CMYK model, M is the grayscale value of the magenta channel in the CMYK model; Y is the grayscale value of the yellow channel in the CMYK model; K is the grayscale value of the black in the CMYK model.

[0079] Step 202: Compare the first CMYK format image with the second CMYK format image to obtain the grayscale adjustment values of each grayscale adjustment area of the image;

[0080] The second CMYK format image is a CMYK format image obtained by the raster image processor RIP processing the original image before the inkjet printer prints.

[0081] As an optional method, the comparing the first CMYK format image with the second CMYK format image to obtain the grayscale adjustment values of each grayscale adjustment area of the image includes:

[0082] Calculate the difference between the first grayscale value of the pixel point in the first CMYK format image and the second grayscale value of the corresponding pixel point in the second CMYK format image; it can be understood that both the first grayscale value and the second grayscale value are the grayscale values corresponding to each channel of CMYK.

[0083] Determine the initial gray-scale adjustment value of the gray-scale adjustment area according to the difference value; if the first gray-scale value is greater than the second gray-scale value, the initial gray-scale adjustment value is to reduce the difference value, and if the first gray-scale value is less than the second gray-scale value, the initial gray-scale adjustment value is to increase the difference value; it should be noted that for a gray-scale adjustment area, since the gray-scale values of all pixel points in this area may not be exactly the same, after calculating the difference value, this area may contain multiple different but approximate difference values, and these values are collectively referred to as the initial gray-scale adjustment values. In order to simplify the operation, a fuzzy operation is performed on the initial gray-scale adjustment values of the gray-scale adjustment areas to obtain the target gray-scale adjustment values of each gray-scale adjustment area of the image. In this way, the gray-scale adjustment values of each pixel in a gray-scale adjustment area can be unified into one value, which is convenient for subsequent calculations.

[0084] Step 203: According to the gray-scale adjustment values of each gray-scale adjustment area of the image, use the Poisson disk sampling algorithm to perform dot layout adjustment of the corresponding density on the second CMYK format image to obtain the adjusted CMYK format image;

[0085] The above step 203 may specifically include the following steps:

[0086] Step S1: Calculate the target percentage of the gray-scale adjustment value in the gray-scale values of the gray-scale adjustment area in the second CMYK format image;

[0087] Dividing the gray-scale adjustment value by the gray-scale values of the gray-scale adjustment area in the second CMYK format image can obtain the target percentage, and this target percentage is equivalent to the percentage of the pixel point density to be adjusted.

[0088] Step S2: Use the Poisson disk sampling algorithm to determine the target pixel point layout diagram corresponding to the target percentage;

[0089] As an optional method, the above step S2 may include:

[0090] Substitute the target percentage into formula (8):

[0091] sampleCount = width × height × M (8)

[0092] Calculate the target sample quantity; where sampleCount is the target sample quantity, width is the width of the target pixel point layout diagram, height is the height of the target pixel point layout diagram, and M is the target percentage;

[0093] Substitute the target sample quantity into formula (9):

[0094] minDistance = sqrt(width × height / sampleCount) (9)

[0095] Obtain the minimum radius;

[0096] Randomly select pixel point samples that meet the preset conditions in the initial pixel point layout diagram according to the minimum radius to obtain the target pixel point layout diagram corresponding to the target percentage. The obtained target pixel point layout diagram includes the target pixel point layout diagrams corresponding to each gray-scale adjustment area.

[0097] The target pixel point layout is linearly given according to the target percentage. Therefore, adjusting the gray-scale adjustment area according to the target pixel point layout can be adjusted linearly, reducing the labor intensity and enhancing the real-time performance.

[0098] Further, the randomly selecting pixel point samples that meet the preset conditions in the initial pixel point layout diagram according to the minimum radius to obtain the target pixel point layout diagram corresponding to the target percentage includes:

[0099] Randomly generate an initial pixel point in the initial pixel point layout diagram and save the initial pixel point into a random array; the initial pixel point layout diagram is a blank diagram with a preset size of width×height. Since the target pixel point layout is the position diagram of the point layout with the target percentage gray scale, which actually reflects the density distribution of pixel points, and the initial pixel point layout diagram is a custom sampling area, the initial pixel point layout diagram can be exactly the same as or different from the shape and size of the gray-scale adjustment area.

[0100] Randomly generate N pixel points on a ring with the initial pixel point as the center, the minimum radius as the inner diameter, and the maximum radius as the outer diameter, where N is a positive integer and the maximum radius is twice the minimum radius;

[0101] Check each of the N pixel points one by one, and save the pixel points whose distances from all the generated pixel points are greater than or equal to the minimum radius into the random array; the pixel points whose distances from all the generated pixel points are greater than or equal to the minimum radius are the pixel point samples that meet the preset conditions.

[0102] Continue sampling with a pixel point randomly selected from the random array as the center until there are no pixel points that meet the preset conditions in the initial pixel point layout diagram to obtain the target pixel point layout diagram corresponding to the target percentage. It should be noted that "continue sampling with a pixel point randomly selected from the random array as the center" is a repetition of the step of "randomly generate N pixel points on a ring with a pixel point randomly selected from the random array as the center, the minimum radius as the inner diameter, and the maximum radius as the outer diameter; check each of the N pixel points one by one, and save the pixel points whose distances from all the generated pixel points are greater than or equal to the minimum radius into the random array". It can be understood that the pixel points in the random array are the data of the target pixel point layout diagram.

[0103] Step S3: Adjust the pixel density of the gray-scale adjustment area in the second CMYK format image according to the target pixel layout diagram, so that the pixel density of the adjusted gray-scale adjustment area increases or decreases by the target percentage compared with that before adjustment, and obtain the adjusted CMYK format image.

[0104] As an optional method, step S3 may include the following steps:

[0105] Step S31: If the pixel density of the adjusted gray-scale adjustment area increases by the target percentage compared with that before adjustment, superimpose the target pixel layout diagram on the gray-scale adjustment area. If the pixels in the target pixel layout diagram coincide with the pixels in the gray-scale adjustment area, fine-tune the pixels in the target pixel layout diagram to positions that do not coincide with the pixels in the gray-scale adjustment area, so that the pixels in the target pixel layout diagram and the pixels in the gray-scale adjustment area do not overlap, obtain the addition positions of the pixels in the target pixel layout diagram in the gray-scale adjustment area of the second CMYK format image, add pixels at the addition positions, and obtain the adjusted CMYK format image;

[0106] Step S32: If the pixel density of the adjusted gray-scale adjustment area decreases by the target percentage compared with that before adjustment, superimpose the target pixel layout diagram on the gray-scale adjustment area, find the point closest to each pixel in the target pixel layout diagram in the gray-scale adjustment diagram, and adjust it to that point position, so that the pixels in the target pixel layout diagram and the pixels in the gray-scale adjustment area overlap. The deletion positions of the pixels in the target pixel layout diagram in the gray-scale adjustment area of the second CMYK format image are obtained, and pixels are deleted at the deletion positions to obtain the adjusted CMYK format image.

[0107] In practical applications, when the preset size of the initial pixel layout diagram is exactly the same as the shape and size of the gray-scale adjustment area, or both the width and height of the preset size are larger than those of the gray-scale adjustment area, the adjustment of the gray-scale adjustment area can be completed directly according to the steps of step S31 and step S32 above; if the preset size is smaller than the size of the gray-scale adjustment area, after performing step S31 or step S32, the target pixel layout diagram can be moved by the width distance along the width direction or the height distance along the height direction, and then step S31 or step S32 is continued until the moved target pixel layout diagram completely covers the gray-scale adjustment area, and the adjustment of the gray-scale adjustment area is completed.

[0108] As an alternative, the calculated target pixel layout map can be saved as a lookup table. During actual operation, the target pixel layout map required for each gray-scale adjustment area can be directly obtained by looking up the table, and then adjustment can be performed to improve the system operation performance. Specifically, after determining the target pixel layout map corresponding to the target percentage by using the Poisson disk sampling algorithm, the following steps are further included:

[0109] Generating image blocks corresponding to the gray scales of each target percentage according to the target pixel layout map;

[0110] Saving the image blocks corresponding to the gray scales of each target percentage as a lookup table;

[0111] Extracting the corresponding image block from the lookup table according to the target percentage required for adjustment in the gray-scale adjustment area in the second CMYK format image;

[0112] Adjusting the pixel density of the pixels in the gray-scale adjustment area of the second CMYK format image according to the extracted image block, so that the pixel density of the adjusted gray-scale adjustment area increases or decreases by the target percentage compared with that before adjustment, and obtaining the adjusted CMYK format image.

[0113] It can be understood that the target pixel layout maps corresponding to the gray scales of 1% - 99% target percentages can be calculated in advance, the corresponding image blocks can be generated, and saved as a lookup table, and then the table can be directly looked up during actual application.

[0114] Step 204: Printing according to the adjusted CMYK format image to obtain a target printed image.

[0115] The target printed image is the image printed by an inkjet printer after the printing color difference adjustment is completed.

[0116] The above method directly collects the image printed by the inkjet printer using a machine vision system, then compares the collected image with the second CMYK format image stored in the printing engine to obtain the gray-scale adjustment parameters, and feeds the gray-scale adjustment parameters back to the printing engine. The printing engine adjusts the second CMYK format image according to the gray-scale adjustment parameters, which can dynamically adjust the printing color difference of the inkjet printer. Since the Poisson disk sampling algorithm is adopted, the gray-scale adjustment of the CMYK format image can be directly performed according to the gray-scale adjustment value, so that the gray-scale adjustment value can be directly fed back to the back end of the RIP, that is, the printing engine. The printing engine can directly print the adjusted CMYK format image without going through a series of processes of the RIP, which reduces the performance requirements of the device and also avoids the problem of inconvenient use of having to re-check the adjustment range of the RIP after adjusting the printing position. At the same time, since the printing engine retains the information of the actual corresponding nozzles and nozzle holes of each pixel of the image when processing the second CMYK image obtained after RIP processing, the adjusted CMYK format image data obtained by performing dot distribution adjustment of the corresponding density on the second CMYK format image according to the gray-scale adjustment value fed back to the printing engine can correspond to the printer layout. In addition, the Poisson disk sampling algorithm is used to adjust the image, which ensures the uniformity of dot distribution and conforms to the human eye characteristics. The target pixel point layout is linearly given according to the target percentage. Therefore, adjusting the gray-scale adjustment area according to the target pixel point layout can be adjusted linearly, reducing the labor intensity and enhancing the real-time performance.

[0117] Embodiments of the present invention can divide functional modules according to the above method. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiments of the present invention is illustrative, only a logical function division, and there may be other division methods in actual implementation.

[0118] In the case of dividing each functional module corresponding to each function, Figure 3 shows a structural schematic diagram of a device for dynamically adjusting the printing color difference of a printer provided by the present invention. As Figure 3 shown, the device includes:

[0119] An RGB image acquisition module 301, configured to acquire the RGB image collected by the vision system and convert the RGB image into a first CMYK format image;

[0120] A gray-scale adjustment value determination module 302, configured to compare the first CMYK format image with the second CMYK format image to obtain the gray-scale adjustment values of each gray-scale adjustment area of the image;

[0121] The CMYK format image adjustment module 303 is configured to perform dot layout adjustment of corresponding density on the second CMYK format image by using the Poisson disk sampling algorithm according to the gray scale adjustment values of the gray scale adjustment regions of the image, so as to obtain an adjusted CMYK format image;

[0122] After the color difference adjustment is completed, the printing module 304 is configured to perform printing according to the adjusted CMYK format image to obtain a target printed image.

[0123] Optionally, the CMYK format image adjustment module 303 may include:

[0124] A target percentage calculation unit configured to calculate a target percentage of the gray scale adjustment value in the gray scale value of the gray scale adjustment region in the second CMYK format image;

[0125] A target pixel point layout map determination unit configured to determine a target pixel point layout map corresponding to the target percentage by using the Poisson disk sampling algorithm;

[0126] An adjusted CMYK format image determination unit configured to adjust the pixel point density of the gray scale adjustment region in the second CMYK format image according to the target pixel point layout map, so that the pixel point density of the adjusted gray scale adjustment region increases or decreases by the target percentage compared with that before adjustment, thereby obtaining an adjusted CMYK format image.

[0127] Optionally, the target pixel point layout map determination unit may specifically include:

[0128] Substitute the target percentage into

[0129] sampleCount = width × height × M

[0130] Calculate to obtain a target sample quantity; where sampleCount is the target sample quantity, width is the width of the target pixel point layout map, height is the height of the target pixel point layout map, and M is the target percentage;

[0131] Substitute the target sample quantity into

[0132] minDistance = sqrt(width × height / sampleCount)

[0133] Obtain the minimum radius;

[0134] Randomly select pixel point samples that meet the preset conditions in the initial pixel point layout map according to the minimum radius to obtain a target pixel point layout map corresponding to the target percentage.

[0135] Optionally, the target pixel layout map determination unit may further be configured to:

[0136] Randomly generate an initial pixel in the initial pixel layout map, and save the initial pixel into a random array;

[0137] Randomly generate N pixels on a ring centered on the initial pixel, where the inner diameter is the minimum radius and the outer diameter is the maximum radius, N is a positive integer, and the maximum radius is twice the minimum radius;

[0138] Check each of the N pixels one by one, and save the pixels whose distances from all the generated pixels are greater than or equal to the minimum radius into the random array;

[0139] Continue sampling with a pixel randomly selected from the random array until there are no pixels in the initial pixel layout map that meet the preset conditions, and obtain the target pixel layout map corresponding to the target percentage.

[0140] Optionally, the adjusted CMYK format image determination unit may be configured to:

[0141] If the pixel density of the adjusted grayscale adjustment area increases by the target percentage compared to before adjustment, then superimpose the target pixel layout map on the grayscale adjustment area so that the pixels in the target pixel layout map do not overlap with the pixels in the grayscale adjustment area, obtain the addition positions of the pixels in the target pixel layout map in the grayscale adjustment area of the second CMYK format image, and add pixels at the addition positions to obtain the adjusted CMYK format image;

[0142] If the pixel density of the adjusted grayscale adjustment area decreases by the target percentage compared to before adjustment, then superimpose the target pixel layout map on the grayscale adjustment area so that the pixels in the target pixel layout map overlap with the pixels in the grayscale adjustment area, obtain the deletion positions of the pixels in the target pixel layout map in the grayscale adjustment area of the second CMYK format image, and delete pixels at the deletion positions to obtain the adjusted CMYK format image.

[0143] Optionally, the grayscale adjustment value determination module 302 may specifically include:

[0144] A difference calculation unit, configured to calculate the difference between the first grayscale value of the pixel in the first CMYK format image and the second grayscale value of the corresponding pixel in the second CMYK format image;

[0145] An initial grayscale adjustment value determination unit, configured to determine an initial grayscale adjustment value for a grayscale adjustment area according to the difference value; if the first grayscale value is greater than the second grayscale value, the initial grayscale adjustment value is to reduce the difference value, and if the first grayscale value is less than the second grayscale value, the initial grayscale adjustment value is to increase the difference value;

[0146] A target grayscale adjustment value determination unit, configured to perform a fuzzy operation on the initial grayscale adjustment value of the grayscale adjustment area to obtain a target grayscale adjustment value for each grayscale adjustment area of the image.

[0147] Optionally, the device further includes a look-up table operation module, and the look-up table operation module may include:

[0148] An image block determination unit, configured to generate image blocks corresponding to the grayscales of each target percentage according to the target pixel point layout map;

[0149] A look-up table establishment unit, configured to save the image blocks corresponding to the grayscales of each target percentage as a look-up table;

[0150] A look-up unit, configured to extract a corresponding image block from the look-up table according to the target percentage required for adjustment in the grayscale adjustment area of the second CMYK format image;

[0151] An adjustment unit, configured to adjust the pixel point density of the pixel points in the grayscale adjustment area of the second CMYK format image according to the extracted image block, so that the pixel point density of the adjusted grayscale adjustment area increases or decreases by the target percentage compared with that before adjustment, and obtain an adjusted CMYK format image.

[0152] The above mainly introduces the solution provided by the embodiment of the present invention from the perspective of the interaction between each network element. It can be understood that, in order to implement the above functions, it includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should easily realize that, combining the units and algorithm steps of each example described in the embodiments disclosed in this article, the present invention can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0153] In the case of adopting corresponding integrated units, Figure 4 The structural schematic diagram of a device for dynamically adjusting the printing color difference of a printer provided by the present invention is shown. As Figure 4 shown, the device includes:

[0154] A communication unit / communication interface for acquiring an RGB image collected by a vision system and converting the RGB image into a first CMYK format image;

[0155] A processing unit / processor for comparing the first CMYK format image with a second CMYK format image to obtain gray-scale adjustment values for each gray-scale adjustment region of the image;

[0156] According to the gray-scale adjustment values for each gray-scale adjustment region of the image, using the Poisson disk sampling algorithm to perform dot distribution adjustment of corresponding density on the second CMYK format image to obtain an adjusted CMYK format image;

[0157] Performing printing according to the adjusted CMYK format image to obtain a target printed image.

[0158] Wherein, the processing unit can be a processor or a controller. For example, it can be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logic blocks, modules and circuits described in connection with the disclosure of the present invention. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on. The communication module can be a transceiver, a transceiver circuit or a communication interface, etc. The storage module can be a memory.

[0159] The above-mentioned processor can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present invention. The above-mentioned communication interface can be one or more. The communication interface can use any device such as a transceiver for communicating with other devices or communication networks.

[0160] As Figure 4 shown, the above-mentioned terminal device may further include a communication line. The communication line may include a path for transmitting information between the above-mentioned components.

[0161] Optionally, as Figure 4As shown, the terminal device may further include a memory. The memory is used to store computer-executable instructions for implementing the solution of the present invention, and is controlled by the processor for execution. The processor is used to execute the computer-executable instructions stored in the memory, thereby implementing the method provided by the embodiments of the present invention.

[0162] As Figure 4 shown, the memory may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor through a communication line. The memory may also be integrated with the processor.

[0163] Optionally, the computer-executable instructions in the embodiments of the present invention may also be referred to as application code, and the embodiments of the present invention do not make specific limitations thereto.

[0164] In a specific implementation, as an embodiment, as Figure 4 shown, the processor may include one or more CPUs, such as Figure 4 CPU0 and CPU1 in

[0165] In a specific implementation, as an embodiment, as Figure 4 shown, the terminal device may include multiple processors, such as Figure 4 the processors in

[0166] On the one hand, a computer-readable storage medium is provided, and instructions are stored in the computer-readable storage medium. When the instructions are run, the method for dynamically adjusting the printing color difference of a printer is implemented.

[0167] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present invention are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a terminal, a user device, or other programmable devices. The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it can also be an optical medium, such as a digital video disc (DVD); or it can be a semiconductor medium, such as a solid state drive (SSD).

[0168] Although the present invention has been described in conjunction with various embodiments, however, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality. A single processor or other unit can implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0169] Although the present invention has been described in connection with specific features and their embodiments, it is obvious that various modifications and combinations can be made without departing from the spirit and scope of the present invention. Accordingly, the present specification and the drawings are merely exemplary descriptions of the present invention defined by the appended claims, and are considered to have covered any and all modifications, variations, combinations, or equivalents within the scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A method for dynamically adjusting the color difference of a printer, characterized in that: include: Acquire an RGB image acquired by a visual system, and convert the RGB image into a first CMYK format image; The first CMYK format image is compared with the second CMYK format image to obtain the grayscale adjustment value of each grayscale adjustment area of ​​the image; the second CMYK format image is a CMYK format image obtained by processing the original image by a raster image processor before printing by the inkjet printer; According to the grayscale adjustment value of each grayscale adjustment area of ​​the image, a Poisson disk sampling algorithm is used to adjust the dot distribution of the second CMYK format image with a corresponding density to obtain an adjusted CMYK format image; Printing is performed according to the adjusted CMYK format image to obtain a target printed image; The step of adjusting the distribution of dots of the second CMYK format image according to the grayscale adjustment value of each grayscale adjustment area of ​​the image by using the Poisson disk sampling algorithm to obtain the adjusted CMYK format image includes: Calculate the target percentage of the grayscale adjustment value to the grayscale value of the grayscale adjustment area in the second CMYK format image; Substituting the target percentage into sampleCount=width×height×M Calculate the target sample number; where sampleCount is the target sample number, width is the width of the target pixel layout map, height is the height of the target pixel layout map, and M is the target percentage; Substituting the target sample size into minDistance=sqrt(width×height / sampleCount) Get the minimum radius; Among them, minDistance is the minimum radius; Randomly selecting pixel samples that meet preset conditions in the initial pixel layout map according to the minimum radius, and obtaining a target pixel layout map corresponding to the target percentage; The pixel density of the grayscale adjustment area in the second CMYK format image is adjusted according to the target pixel layout diagram, so that the pixel density of the grayscale adjustment area after adjustment increases or decreases by a target percentage compared with before adjustment, thereby obtaining an adjusted CMYK format image.

2. The method for dynamically adjusting the color difference of a printer according to claim 1, characterized in that: The randomly selecting pixel samples that meet a preset condition in the initial pixel layout map according to the minimum radius to obtain a target pixel layout map corresponding to the target percentage includes: Randomly generate an initial pixel point in the initial pixel point layout map, and save the initial pixel point into a random array; Randomly generate N pixel points on a circle with the initial pixel point as the center, the minimum radius as the inner diameter, and the maximum radius as the outer diameter, where N is a positive integer and the maximum radius is twice the minimum radius; Check the N pixel points one by one, and save the pixel points whose distances to all generated pixel points are greater than or equal to the minimum radius into the random array; Taking a pixel point randomly selected from the random array as the center, sampling is continued until there are no pixels satisfying the preset conditions in the initial pixel point layout diagram, thereby obtaining a target pixel point layout diagram corresponding to the target percentage.

3. The method for dynamically adjusting the color difference of a printer according to claim 1, characterized in that: The step of adjusting the pixel density of the grayscale adjustment area in the second CMYK format image according to the target pixel layout diagram so that the pixel density of the grayscale adjustment area after adjustment increases or decreases by a target percentage compared with that before adjustment, and obtaining the adjusted CMYK format image comprises: If the pixel density of the grayscale adjustment area after adjustment increases by a target percentage compared to before adjustment, superimpose the target pixel layout map with the grayscale adjustment area so that the pixels in the target pixel layout map and the pixels in the grayscale adjustment area do not overlap, obtain the added positions of the pixels in the target pixel layout map in the grayscale adjustment area of ​​the second CMYK format image, add pixels at the added positions, and obtain the adjusted CMYK format image; If the pixel density of the grayscale adjustment area after adjustment is reduced by a target percentage compared to before adjustment, the target pixel layout map and the grayscale adjustment area are superimposed so that the pixels in the target pixel layout map overlap with the pixels in the grayscale adjustment area, and the pixels in the target pixel layout map are deleted at the deletion position in the grayscale adjustment area of ​​the second CMYK format image, and the adjusted CMYK format image is obtained.

4. The method for dynamically adjusting the color difference of a printer according to claim 1, characterized in that: The step of comparing the first CMYK format image with the second CMYK format image to obtain the grayscale adjustment value of each grayscale adjustment area of ​​the image comprises: Calculating a difference between a first grayscale value of a pixel in the first CMYK format image and a second grayscale value of a pixel corresponding to the second CMYK format image; Determine an initial grayscale adjustment value of the grayscale adjustment area according to the difference; if the first grayscale value is greater than the second grayscale value, the initial grayscale adjustment value is to reduce the difference; if the first grayscale value is less than the second grayscale value, the initial grayscale adjustment value is to increase the difference; A fuzzy operation is performed on the initial grayscale adjustment value of the grayscale adjustment area to obtain a target grayscale adjustment value of each grayscale adjustment area of ​​the image.

5. The method for dynamically adjusting the color difference of a printer according to claim 1, characterized in that: After the Poisson disk sampling algorithm is used to determine the target pixel point layout map corresponding to the target percentage, the following further comprises: Generate image blocks corresponding to the grayscale of each target percentage according to the target pixel layout diagram; The image blocks corresponding to the grayscale of each target percentage are saved as a lookup table; Extracting a corresponding image block from the lookup table according to a target percentage of the grayscale adjustment area in the second CMYK format image that needs to be adjusted; The pixel density of the grayscale adjustment area in the second CMYK format image is adjusted according to the extracted image block, so that the pixel density of the grayscale adjustment area after adjustment increases or decreases by a target percentage compared with before adjustment, thereby obtaining an adjusted CMYK format image.

6. A device for dynamically adjusting the color difference of a printer, characterized in that: include: An RGB image acquisition module, used to acquire an RGB image collected by a visual system, and convert the RGB image into a first CMYK format image; a grayscale adjustment value determination module, configured to compare the first CMYK format image with the second CMYK format image to obtain grayscale adjustment values ​​of each grayscale adjustment area of ​​the image; the second CMYK format image is a CMYK format image obtained by processing the original image by a raster image processor before printing by the inkjet printer; A CMYK format image adjustment module, configured to adjust the dot distribution of the second CMYK format image according to the grayscale adjustment value of each grayscale adjustment area of ​​the image by using a Poisson disk sampling algorithm to obtain an adjusted CMYK format image; After the color difference adjustment is completed, the printing module is used to print according to the adjusted CMYK format image to obtain a target printed image; The CMYK format image adjustment module includes a target percentage calculation unit, which is used to calculate the target percentage of the grayscale adjustment value to the grayscale value of the grayscale adjustment area in the second CMYK format image; A target pixel point layout map determining unit, used to determine a target pixel point layout map corresponding to the target percentage by using a Poisson disk sampling algorithm; an adjusted CMYK format image determining unit, configured to adjust the pixel density of the grayscale adjustment area in the second CMYK format image according to the target pixel layout diagram, so that the pixel density of the grayscale adjustment area after the adjustment is increased or decreased by a target percentage compared with that before the adjustment, thereby obtaining an adjusted CMYK format image; The target pixel point layout map determining unit is used for: Substituting the target percentage into sampleCount=width×height×M Calculate the target sample number; where sampleCount is the target sample number, width is the width of the target pixel layout map, height is the height of the target pixel layout map, and M is the target percentage; Substituting the target sample size into minDistance=sqrt(width×height / sampleCount) Get the minimum radius; Pixel samples that meet preset conditions are randomly selected from the initial pixel layout map according to the minimum radius to obtain a target pixel layout map corresponding to the target percentage.

7. A device for dynamically adjusting the color difference of a printer, characterized in that: include: A communication unit / communication interface, used to obtain an RGB image acquired by a visual system, and convert the RGB image into a first CMYK format image; A processing unit / processor, used for comparing the first CMYK format image with the second CMYK format image to obtain grayscale adjustment values ​​of each grayscale adjustment area of ​​the image; the second CMYK format image is a CMYK format image obtained by processing the original image by a raster image processor before printing by the inkjet printer; According to the grayscale adjustment value of each grayscale adjustment area of ​​the image, a Poisson disk sampling algorithm is used to adjust the dot distribution of the second CMYK format image with a corresponding density to obtain an adjusted CMYK format image; Printing is performed according to the adjusted CMYK format image to obtain a target printed image; The step of adjusting the distribution of dots of the second CMYK format image according to the grayscale adjustment value of each grayscale adjustment area of ​​the image by using the Poisson disk sampling algorithm to obtain the adjusted CMYK format image includes: Calculate the target percentage of the grayscale adjustment value to the grayscale value of the grayscale adjustment area in the second CMYK format image; Substituting the target percentage into sampleCount=width×height×M Calculate the target sample number; where sampleCount is the target sample number, width is the width of the target pixel layout map, height is the height of the target pixel layout map, and M is the target percentage; Substituting the target sample size into minDistance=sqrt(width×height / sampleCount) Get the minimum radius; Among them, minDistance is the minimum radius; Randomly selecting pixel samples that meet preset conditions in the initial pixel layout map according to the minimum radius, and obtaining a target pixel layout map corresponding to the target percentage; The pixel density of the grayscale adjustment area in the second CMYK format image is adjusted according to the target pixel layout diagram, so that the pixel density of the grayscale adjustment area after adjustment increases or decreases by a target percentage compared with before adjustment, thereby obtaining an adjusted CMYK format image.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed, the method for dynamically adjusting the color difference of printer printing as described in any one of claims 1 to 5 is implemented.

Images