A method for improving the stair-step problem of inkjet pixels

Abstract

The application discloses a method for improving the pixel step problem of inkjet printing. After the alignment of the finished product, the system reads the printing image after rotation correction, and performs morphological close operation on the printing image. After the morphological close operation, the connected region of the printing image is extracted, the specific pattern to be printed is determined, the hole position corresponding to the printing pattern on the product is set as the image region not to be processed and is excluded, so that the image region to be processed is selected. The selected image region is subjected to open operation of a rectangular operator, and the difference operation is performed on the calculated inscribed rectangle and circumscribed rectangle. The result is intersected with the connected region, so that the position of the pixel step is obtained. Finally, according to the direction of the rotation deviation angle, the pixel step position is completed or deleted, so that the sawtooth and edge unsmooth conditions of the partial region of the printed image are avoided during the rotation correction, and the printing quality is improved.

Description

A method to improve the pixel staircase problem in inkjet printing Technical Field

[0001] This invention relates to the field of inkjet printing technology, and in particular to a method for improving the pixel staircase problem in inkjet printing. Background Technology

[0002] A printer is an automated device used to print graphics on PCD and FPC. During the alignment process, rotational deviations can occur, requiring the data and the printed product to be rotated for correction. There are two methods for rotational correction: First, the printing table has a built-in rotation axis, and correction is achieved by controlling the rotation axis; second, the printed data is rotated to achieve rotational correction. Currently, based on the rotational deviation correction method, printers can be classified into those with a T-axis and those without. Printers with a T-axis increase costs, and the increased table weight leads to a greater load on the equipment. Printers without a T-axis suffer from pixel staggering in the printed image due to image rotation, resulting in jagged edges and uneven edges in some areas of the printed image.

[0003] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method to improve the pixel staircase problem in inkjet printing.

[0005] The technical solution of the present invention is as follows: A method for improving the pixel staircase problem in inkjet printing is provided, comprising the following steps:

[0006] Step 1: Upload image data and read the rotated and corrected printed image;

[0007] Step 2: Perform morphological closing operations on the printed image;

[0008] Step 3: Based on the closing operation result, obtain the connected regions of the rotated printed image;

[0009] Step 4: Eliminate image regions that do not need to be processed;

[0010] Step 5: Calculate the position of the pixel steps for the area to be processed;

[0011] Step 6: Based on the rotation deviation angle direction, complete or delete the pixel step positions.

[0012] Furthermore, in step 2, the specific steps of the morphological closing operation are as follows:

[0013] Step 2.1: Perform dilation processing on the printed image first;

[0014] Step 2.2: Perform erosion processing on the dilated image to restore the shape and size of the dilated region.

[0015] Furthermore, the basis for excluding image areas that do not require processing in step 4 includes the position and size of the inscribed circle and / or holes on the printed surface.

[0016] Furthermore, the specific steps of step 5 are as follows:

[0017] Step 5.1: Based on the areas excluded in Step 4, determine the areas that need to be processed, and perform the opening operation of the rectangle operator to obtain the inscribed rectangle and the bounding rectangle;

[0018] Step 5.2: Perform the difference operation between the obtained inscribed rectangle and the bounding rectangle;

[0019] Step 5.3: Based on the result of the difference operation, perform an intersection operation with the connected region to obtain the position of the pixel staircase.

[0020] Furthermore, the specific steps of the opening operation of the rectangle operator in step 5.1 are as follows: perform erosion processing on the image within the selected area, perform noise reduction and compression on the image, perform dilation processing on the eroded image to further remove noise, retain the original image, and obtain the inscribed rectangle and the bounding rectangle.

[0021] Furthermore, the specific steps of the difference operation in step 5.2 are as follows: subtract the inscribed rectangular region and the common area between the regions from the circumscribed rectangular region to obtain a new region.

[0022] Furthermore, the specific steps of the intersection operation in step 5.3 are as follows: based on the region output by the difference operation result obtained in step 5.2, compare it with the common part between the region and the connected region, and delete other regions outside the common part to obtain the pixel step position.

[0023] By employing the above-mentioned scheme, the present invention processes and calculates the position of the pixel steps in the rotated and corrected printed image, thereby completing or deleting the pixel steps. This avoids jagged edges and uneven edges in some areas of the printed image while performing rotation correction, thus improving print quality. Detailed Implementation

[0024] The present invention will be described in detail below with reference to specific embodiments.

[0025] This invention provides a method for improving the pixel staircase problem in inkjet printing, comprising the following steps:

[0026] Step 1: Upload image data and read the rotated and corrected printed image.

[0027] Step 2: Perform morphological closing operations on the printed image. The purpose is to fill in the small holes, facilitating the subsequent positioning of pixel steps. The closing operation involves dilation followed by erosion; the specific process is as follows:

[0028] Step 2.1: First, dilate the image. At this time, the small hole area in the image will be filled by the dilation operation.

[0029] Step 2.2: Perform erosion processing on the image. After the dilation process in the previous step, the area will become larger. Erosion processing restores the shape and size of the area.

[0030] Step 3: Based on the closing operation result, obtain the connected regions of the rotated printed image.

[0031] Step 4: Exclude image areas that do not require processing. The basis for excluding image areas that do not require processing in Step 4 includes the position and size of the inscribed circle and / or holes on the printed surface.

[0032] Step 5: Calculate the position of the pixel steps for the area to be processed. The specific steps are as follows:

[0033] Step 5.1: Based on the areas excluded in Step 4, determine the areas to be processed and perform the opening operation of the rectangle operator, followed by the erosion and dilation processes. After erosion, the image is freed from noise but also compressed. Next, dilation is performed on the eroded image to remove noise while preserving the original image, obtaining the inscribed and bounding rectangles.

[0034] Step 5.2: Perform a difference operation on the obtained inscribed rectangle and bounding rectangle. The difference operation process is to remove the specified other regions and the common parts between regions from the region being subtracted, thereby obtaining a new region.

[0035] Step 5.3: Based on the result of the difference operation, perform an intersection operation with the connected regions. The intersection operation consists of the common part of two or more regions. Delete the regions outside the common part to obtain new regions and the position of the pixel ladder.

[0036] Step 6: Based on the rotation deviation angle direction, complete or delete the pixel step positions.

[0037] This invention is applicable to: 1. Printed images that originally lacked pixel staircases but developed them after rotational correction; 2. Printed images that inherently possess pixel staircases. When printing on a device without a T-axis, after product alignment, the system reads the rotationally corrected printed image and performs morphological closing operations to avoid the influence of sampling points on the correction effect. After morphological closing, the connected regions of the printed image are extracted, the specific graphic to be printed is determined, and holes and other locations on the product corresponding to the printed graphic are excluded as image areas that do not require processing, thus selecting the image areas that need processing. A rectangle operator opening operation is performed on the selected image areas to calculate the inscribed and circumscribed rectangles. The difference between the inscribed and circumscribed rectangles is then calculated, and the result is intersected with the extracted connected regions to obtain the pixel staircase positions. Finally, based on the direction of the rotational deviation angle, the pixel staircase positions are either completed or deleted, thereby avoiding jagged edges and uneven edges in parts of the printed image while performing rotational correction, thus improving print quality. Furthermore, using equipment without a T-axis can save on equipment installation and maintenance costs, and reduce the load on the equipment.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the pixel staircase problem in inkjet printing, characterized in that, The process includes the following steps: Step 1: Upload image data and read the rotated and corrected printed image; Step 2: Perform morphological closing operation on the printed image; Step 3: Obtain the connected regions of the rotated and corrected printed image based on the closing operation result; Step 4: Eliminate image regions that do not need processing; Step 5: Calculate the positions of pixel steps for the regions that need processing; Step 6: Complete or delete pixel step positions based on the rotation deviation angle direction; In Step 2, the specific steps of the morphological closing operation are as follows: Step 2.1: Dilate the printed image first; Step 2.2: Erode the dilated image to restore the shape and size of the dilated region; The basis for excluding image regions that do not need processing in Step 4 includes the position and size of the inscribed circle and / or holes on the printed surface. The specific steps of step 5 are as follows: Step 5.1: Based on the regions excluded in step 4, determine the regions to be processed and perform the opening operation of the rectangle operator to obtain the inscribed rectangle and the circumscribed rectangle; Step 5.2: Perform the difference operation based on the obtained inscribed rectangle and circumscribed rectangle; Step 5.3: Based on the result of the difference operation, perform the intersection operation with the connected regions to obtain the position of the pixel staircase; The specific steps of the opening operation of the rectangle operator in step 5.1 are as follows: perform erosion processing on the image within the selected region, perform noise reduction and compression on the image, and then perform dilation processing on the eroded image to further remove noise, retain the original image, and obtain the inscribed rectangle and the circumscribed rectangle; The specific steps of the difference operation in step 5.2 are as follows: subtract the inscribed rectangle region and the common area between the regions from the circumscribed rectangle region to obtain a new region.

2. The method for improving the pixel staircase problem in inkjet printing according to claim 1, characterized in that, The specific steps of the intersection operation in step 5.3 are as follows: based on the region output by the difference operation result obtained in step 5.2, compare it with the common part between the connected regions, and delete other regions outside the common part to obtain the pixel step position.