A method and apparatus for line etching of a thermal sensitive print sheet

Abstract

The application relates to the technical field of image processing, in particular to a circuit etching method and device for a thermal printing sheet, which comprises the following steps: obtaining each structure region in an exposure image of the thermal printing sheet; obtaining pixel disorder degrees of each structure region by equally dividing all pixel values in each structure region and analyzing pixel step changes and pixel value differences in the region; and obtaining an angle point distribution difference degree of each structure region by using angle point features in each structure region, taking corresponding structure regions with the same angle point distribution difference degree as same structure regions of each structure, and then obtaining a search step length of the same structure regions of each structure to etch the circuit of the thermal printing sheet. The application can improve the efficiency of circuit etching of the thermal printing sheet.

Description

Technical Field

[0001] This application relates to the field of image processing technology, specifically to a method and apparatus for etching lines on a thermal printing sheet. Background Technology

[0002] Thermal paper printing technology uses miniature heating elements within the printing sheet to transfer heat to designated areas of the thermal paper. This heat causes a chemical reaction between the leuco dye and the developer in the thermal paper, resulting in color. Therefore, the accuracy of the circuitry within the thermal printing sheet determines the performance of the thermal print. The heating element in thermal printing is a thin-film resistor, typically made of tantalum compounds or mixtures, and is fabricated through an exposure etching process.

[0003] For etching circuitry on thermal printed circuit boards, the resistive coating is typically etched using an exposure method. After etching, the exposure effect needs to be checked to ensure the continuity of subsequent circuitry. During the etching process, the image is enhanced, and the etching effect is determined based on the differences in pixels within the etched area. Traditional methods generally use Non-Local Means (NLM) filtering algorithms for noise reduction. However, due to the piecewise similarity of the circuit structure on thermal printed circuit boards, traditional NLM algorithms, when using a fixed search step size, are prone to generating unnecessary searches, thus increasing the computational load and detection time. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a method and apparatus for etching lines on a thermally printed wafer. The specific technical solution adopted is as follows:

[0005] This application provides a method for etching lines on a thermal printing wafer, including the following steps:

[0006] Obtain each structural region in the exposed image of the thermal print;

[0007] By dividing all pixel values ​​in each structural region into equal parts, a symbol set for each structural region is obtained. The pixel values ​​in the symbol set of each structural region are arranged in ascending order. The pixel order variation of each structural region is obtained by using the difference sequence of the arranged sequence. Then, the pixel disorder of each structural region is obtained by combining the differences of all pixel values ​​in the symbol set of each structural region.

[0008] By analyzing the differences between all corner points and the center point in each structural region, the corner point distribution difference of each structural region can be obtained.

[0009] The structural region with the same corner point distribution difference is taken as the same structure region of each structure, the difference degree of any two corner points in the same structure region is counted, the structural distribution distance of each same structure region is obtained, the search step of the same structure region of each structure is obtained, and then the thermal sensitive printing sheet is subjected to line etching.

[0010] Preferably, the method for obtaining each structural region of the thermal sensitive printing sheet is:

[0011] The post-exposure image collected by the camera is converted into a gray image to obtain an exposure image of the thermal sensitive printing sheet.

[0012] The exposure image of the thermal sensitive printing sheet is subjected to edge detection, and the non-edge pixel points in the edge image are merged to obtain a plurality of non-edge regions, and each structural region in the exposure image of the thermal sensitive printing sheet is obtained by taking the non-edge region as a mask.

[0013] Preferably, the method for obtaining the symbolic set of each structural region comprises:

[0014] All pixel values in each structural region are subjected to quartile equipotential division, and the pixel values between the lower quartile and the upper quartile are combined to form the symbolic set of each structural region.

[0015] Preferably, the pixel order degree of each structural region is the mean value of all elements in the difference sequence of each structural region.

[0016] Preferably, the pixel disorder degree of each structural region is positively correlated with the range value of all pixel values in the symbolic set of each structural region and the pixel order degree of each structural region.

[0017] Preferably, the method for obtaining the center point comprises: performing corner point detection on each structural region, and taking the mean value of all corner point pixel positions in each structural region as the center point of each structural region.

[0018] Preferably, the calculation method of the corner point distribution difference of each structural region comprises:

[0019] ;

[0020] In the formula, is the corner point distribution difference of the i th structural region; is the number of all corner points in the i th structural region; is the mean value of the Euclidean distance between all corner points and the corresponding center point in the i th structural region; is the variance of the Euclidean distance between all corner points and the corresponding center point in the i th structural region; is a preset constant.

[0021] Preferably, the method for obtaining the structure distribution distance of each homogenous structure region is as follows:

[0022] The Euclidean distance between any two corner points in the homogenous structure region is counted, and the square root of the maximum value and the minimum value square sum of all Euclidean distances is obtained as the structure distribution distance of each homogenous structure region.

[0023] Preferably, the method for calculating the search step of the homogenous structure region of each structure is as follows:

[0024] ;

[0025] In the formula, is the search step of the homogenous structure region of the jth structure; is the mean value of the pixel disorder degree of all structure regions in the homogenous structure region of the jth structure; is the mean value of the structure distribution distance of all structure regions in the homogenous structure region of the jth structure; is the maximum value of the Euclidean distance between any two corner points in all structure regions; is a summation normalization function; is a rounding function.

[0026] The embodiment of the present application also provides a line etching device of a thermal printing sheet, wherein the device stores a computer program, and the computer program is executed by a processor to realize the steps of the line etching method of the thermal printing sheet.

[0027] As can be seen from the above, the line etching method and device of the thermal printing sheet provided by the present application have at least the following beneficial effects:

[0028] The present application fully considers that the traditional filtering method denoising adopts a fixed search step when the thermal printing sheet is subjected to line etching, which is easy to cause unnecessary search. Therefore, the exposure image is divided into structure regions by an edge detection algorithm, and the corner point distribution difference degree of the structure region is calculated according to the corner point distribution state of the structure region, so as to distinguish the homogenous structure region in the exposure image of the thermal printing sheet, so as to process the exposure image, which is helpful to enhance the image, improve the image definition and reduce the noise in the image.

[0029] Further, by the shape distribution state of the same structure region, the search efficiency of the NLM algorithm can be improved, the search amount of the algorithm is reduced, the denoising time of the exposure image is shortened, and then the time consumption of the thermal sensitive printing sheet in the exposure process is shortened. By the search step of the improved NLM algorithm, the exposure image of the thermal sensitive printing sheet is enhanced, the noise in the exposure image can be quickly identified and processed. The enhanced image has higher definition, and the defects and residual regions in the line can be more accurately identified, so that the fast secondary exposure of the plating residual region is realized, the exposure time and the exposure etching time are shortened, and the efficiency of the line etching of the thermal sensitive printing sheet is improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0031] Figure 1 A step flow chart of a line etching method of a thermal sensitive printing sheet provided by the present application. DETAILED DESCRIPTION

[0032] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation, structure, features and effects of a line etching method and equipment of a thermal sensitive printing sheet according to the present application are described in detail as follows by combining with the drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0033] Unless otherwise defined and limited, such as the terms "comprise", "include" or any other variants thereof, are intended to cover non-exclusive inclusion, so that the circuit structure, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such article or equipment. Without more limitation, the element limited by the statement "including one" does not exclude the presence of another identical element in the article or equipment including the element. In addition, the term "and / or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as understood by those skilled in the art of the technology to which the present application belongs.

[0034] The application provides a circuit etching method and device for a thermal printing sheet.

[0035] Please refer to Figure 1 which shows a step flow chart of a circuit etching method for a thermal printing sheet according to an embodiment of the application, including the following steps:

[0036] Step 1: Obtain each structure region in an exposure image of the thermal printing sheet.

[0037] The circuit structure of the thermal printing sheet includes a conductor, a heat storage layer, a resistor and a voltage dividing resistor. The conductor is used to transmit a heating electric signal to a heating element to start heating; the heat storage layer uniformly transmits heat to the surface of thermal paper; the resistor is used to convert electric energy into heat energy; and the voltage dividing resistor can ensure that the generated heat is quickly dissipated by the ceramic substrate, so that a heating image is not formed on the printing paper, and the problem of complex processing technology of high-resistance film is solved.

[0038] For the thermal printing sheet with plated resistor film, when exposure etching is performed, the exposure machine determines the exposure area through the built-in positioning algorithm and performs exposure to eliminate the plated layer to be etched. At the same time, the image after exposure collected by the high-precision CCD camera is converted into a gray-scale image by using the weighted average method, and the exposure image of the thermal printing sheet is obtained.

[0039] Since each region in the plated thermal printing sheet has different functions, the circuit structure is not connected, and there is obvious layering between different structures, therefore, the Canny edge detection algorithm is used to perform edge detection on the exposure image of the thermal printing sheet, to obtain an edge image of the exposure image, and the non-edge pixel points in the edge image are merged to obtain a plurality of non-edge regions, and then the non-edge regions are used as a mask to extract the corresponding regions in the exposure image as each structure region in the exposure image of the thermal printing sheet, which is used to represent each functional region in the thermal printing sheet. Preferably, in the embodiment, the weighted average method and the Canny edge detection algorithm are both known technologies, and the specific process is not described again.

[0040] Step 2: Obtain a symbolic set of each structure region by equally dividing all pixel values in each structure region, arrange the pixel values in the symbolic set of each structure region in ascending order, obtain the pixel order degree of each structure region by using the difference sequence of the arranged sequence, and then obtain the pixel disorder degree of each structure region by combining the difference of all pixel values in the symbolic set of each structure region.

[0041] For each structural region of the thermal sensitive printing sheet, the structures of the same function type have the same nature and similarity, and there is a clear boundary between different structures. After exposure, there should be no plating layer remaining in the voltage dividing resistor region, so as to ensure the accuracy of the voltage dividing resistor after etching, and then ensure the stability of the performance of the entire circuit. Since the functionality of each position in each structural region is the same, the same material is used to manufacture each structural region, and therefore the pixels of each position in each structural region should be the same. However, due to the existence of noise, the pixel values of the pixels in the region change to some extent, so that the pixel values are no longer completely the same, and the noise points will cause the pixel values to be larger or smaller, deviating from the overall pixel value level.

[0042] Therefore, the pixel values of all pixels in each structural region are divided into four quartiles, and the pixel values between the lower quartile and the upper quartile are grouped to form a symbolic set of each structural region to represent the pixel distribution of the corresponding structural region as a whole, thereby removing the influence of noise.

[0043] Further, the pixel values of different values in the symbolic set of each structural region are arranged in ascending order, and the arranged sequence is subjected to first-order difference calculation to obtain a difference sequence of each structural region, and then the mean value of all elements in the difference sequence of each structural region is taken as the pixel step change degree of each structural region. Preferably, in the present embodiment, the calculation of the quartile and the first-order difference algorithm are both known technologies, and the specific process will not be repeated.

[0044] Through the above analysis, according to the difference of all pixel values in the symbolic set of each structural region, and combining the pixel step change degree of each structural region, the pixel turbulence degree of each structural region is calculated, and in the present embodiment, the specific calculation formula is:

[0045] ;

[0046] In the formula, is the pixel turbulence degree of the i th structural region; is the range value of all pixel values in the symbolic set of the i th structural region; is the pixel step change degree of the i th structural region.

[0047] wherein, represents the overall pixel difference change of each structural region; The gradient difference degree represents the pixel value change of each structure region. When the difference between the pixel values in a structure region is smaller, it means that the difference of the surface material in the current structure region is smaller, the exposure effect is better, and the pixel step degree value of the current structure region is smaller, and then the pixel disorder degree value of the current structure region is also smaller. The smaller the pixel disorder degree value is, the better the etching effect is, which can ensure the line functionality of the thermal sensitive printing sheet, so that the heat is dissipated more fully in the printing process, and the printing effect is better.

[0048] Step three: obtaining the corner point distribution difference degree of each structure region through the difference between all corner points and the center point in each structure region.

[0049] Since the manufacturing materials and manufacturing processes used in structure regions of the same functionality are the same, the distribution of structure regions of the same functionality on the thermal sensitive printing sheet is consistent, so that the pixel value distribution of structure regions of the same functionality is the same under normal circumstances, and then the pixel disorder degree of structure regions of the same functionality is also the same.

[0050] Further, each structure region pursues smoothness, that is, the distribution of pixel points in each structure region is similar, so that the pixel disorder degree of different structure regions may be similar or the same. However, since different structure regions have different functions, their shapes and sizes are different, so different structure regions have obvious structural differences, and the structure state of the same structure is the same because the line has repeatability.

[0051] Therefore, the Harris corner point detection algorithm is used for corner point detection for each structure region to obtain all corner points of each structure region, and the mean value of the pixel positions of all corner points in each structure region is counted, and the pixel position corresponding to the mean value is taken as the center point of each structure region, and then the mean value of the Euclidean distance between all corner points and the corresponding center point in each structure region is calculated to represent the distribution length of each structure region; the variance of the Euclidean distance between all corner points and the corresponding center point in each structure region is calculated to represent the distribution uniformity of each structure region. Preferably, in the present embodiment, the Harris corner point detection algorithm is a known technology, and the specific process is not described again.

[0052] Through the above analysis, the number of all corner points in each structure region is counted, and the average level and fluctuation of the distance between all corner points and the corresponding center point in each structure region are combined to calculate the corner point distribution difference degree of each structure region. In the present embodiment, the specific calculation formula is:

[0053] ;

[0054] In the formula, is the corner point distribution difference degree of the i th structure region; is the number of all corner points in the i-th structure region; is the average of the Euclidean distance between all corner points and the corresponding center point in the i-th structure region; is the variance of the Euclidean distance between all corner points and the corresponding center point in the i-th structure region; is a preset constant. Since there are symmetrical structures such as squares in the line of the thermal sensitive printing sheet, the variance of the distance between all corner points and the corresponding center point in the symmetrical structure may be 0, thereby causing the corner point distribution difference to be 0. To avoid this situation, The value range of is [1, 10], and is set to 1 in this embodiment.

[0055] For the structure of each part of the line in the thermal sensitive printing sheet, the more complex the structure distribution is, the more complex the shape is, the more the number of corner points formed by the corresponding structure region is, the more uneven the position distribution of the corner points is, the greater the distance value from the center point is, and the greater the variance of the distance from the center point of all corner points is. Therefore, the value of the corner point distribution difference of the structure region is greater, so that the feature between different structure regions is obvious, and each structure region is easy to identify.

[0056] Step four: the structure regions with the same corner point distribution difference are taken as the same structure regions of each structure, and the difference degree between any two corner points in the same structure region is counted to obtain the structure distribution distance of each same structure region, so as to obtain the search step length of the same structure region of each structure, and then the line etching of the thermal sensitive printing sheet is performed.

[0057] Further, since the structures between the same structure regions are similar, the corner point distribution differences of two structure regions are the same. Therefore, the structure regions with the same numerical value of the corner point distribution difference are taken as the same structure regions, and a plurality of same structure regions are obtained. For the same structure region of each structure, the Euclidean distance between any two corner points in the same structure region is calculated to represent the structure distance difference in each structure region, and the square root of the sum of squares of the maximum value of the Euclidean distance and the minimum value of the Euclidean distance is calculated to obtain the structure distribution distance of each same structure region, which is used to represent the distribution difference of each same structure region.

[0058] According to the average level of the structure distribution distance of all structure regions in the same structure region of each structure, and in combination with the average level of the pixel disorder degree of all structure regions in the same structure region of each structure, the search step length of the same structure region of each structure is calculated. In this embodiment, the specific calculation formula is:

[0059] ;

[0060] In the formula, is the average of the structure distribution distance of all structure regions in the same structure region of each structure, is the average of the pixel disorder degree of all structure regions in the same structure region of each structure, and is the search step length of the same structure region of each structure. a search step length of a same structure region of the jth structure; a mean value of pixel disorder degrees of all structure regions in the same structure region of the jth structure; a mean value of structure distribution distances of all structure regions in the same structure region of the jth structure; a maximum value of Euclidean distances between any two corner points in all structure regions; a summation normalization function; a rounding function.

[0061] When the structure shape of a structure region is larger, the distribution of pixel points in the structure region is more likely to be chaotic, and the structure distribution distance of the structure region is larger. Therefore, a longer step length is used to effectively search for similar pixel points in the exposure image, improve the efficiency of image denoising, and further enhance the image quality of the thermal printing sheet circuit, better identify the exposure effect of the resistance area in the circuit, and ensure the function of the thermal printing sheet circuit and improve the efficiency of the printer.

[0062] Therefore, the exposure image and the search step length of all structure regions in the exposure image are used as inputs of the NLM algorithm, and the output is an enhanced image of the exposure image. By enhancing the differences between the same structure regions in the enhanced image, such as the pixel value differences between the same structure regions, the regions with incomplete exposure and residual plating can be determined, and the thermal printing sheet is subjected to secondary exposure according to the positions of the structure regions. Further, the thermal printing sheet after secondary exposure is etched by an etching machine using etching liquid, and the thermal printing sheet after etching is subjected to pickling, thereby realizing a circuit etching method of a thermal printing sheet. The NLM algorithm is a known technology, and the specific process is not described again.

[0063] Based on the same inventive concept as the above method, the embodiments of the present application also provide a circuit etching device of a thermal printing sheet, wherein the device stores a computer program, and the computer program is executed by a processor to realize the steps of the circuit etching method of the thermal printing sheet according to any one of the above methods.

[0064] In addition, a circuit etching device of a thermal printing sheet includes a data collector, an exposure machine, a residual detector, an etching machine, and a pickling machine. The data collector is used to collect data of the thermal printing sheet during the exposure and etching process. The exposure machine is used to expose the thermal printing sheet. The residual detector is used to detect the residual plating of the exposed area of the thermal printing sheet. The etching machine is used to etch the exposed area of the thermal printing sheet. The pickling machine is used to clean the etching liquid.

[0065] It can be understood that the above-mentioned embodiments of the application are only for description, and do not represent the advantages and disadvantages of the embodiments. And the above describes specific embodiments of the specification. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0066] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments.

[0067] The above is only an embodiment of the application, and is not used to limit the scope of the application. Any equivalent structure or equivalent process transformation using the content of the specification and the drawings, or direct or indirect application in other related technical fields, is also included in the protection scope of the application.

Claims

1. A method for etching lines on a thermal printing sheet, characterized in that, Includes the following steps: Obtain each structural region in the exposed image of the thermal print; By dividing all pixel values ​​in each structural region into equal parts, a symbol set for each structural region is obtained. The pixel values ​​in the symbol set of each structural region are arranged in ascending order. The pixel order variation of each structural region is obtained by using the difference sequence of the arranged sequence. Then, the pixel disorder of each structural region is obtained by combining the differences of all pixel values ​​in the symbol set of each structural region. By analyzing the differences between all corner points and the center point in each structural region, the corner point distribution difference of each structural region can be obtained. Structural regions with similar corner point distribution differences are designated as the same structural region for each type of structure. The degree of difference between any two corner points within the same structural region is statistically analyzed to obtain the structural distribution distance of each same structural region. This allows us to obtain the search step size for the same structural region for each type of structure, which is then used to etch lines onto the thermal printout.

2. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining each structural region of the thermal printing sheet is as follows: The exposed image captured by the camera is converted into a grayscale image to obtain the exposed image of the thermal printing sheet; Edge detection is performed on the exposed image of the thermal print sheet, and non-edge pixels in the edge image are merged to obtain multiple non-edge regions. These non-edge regions are used as masks to obtain each structural region in the exposed image of the thermal print sheet.

3. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining the symbol set of each structural region includes: All pixel values ​​in each structural region are divided into quartiles, and the pixel values ​​between the lower quartile and the upper quartile are used to form a symbol set for each structural region.

4. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The pixel-level variation of each structural region is the mean of all elements in the difference sequence of each structural region.

5. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The pixel disorder of each structural region is positively correlated with the range of all pixel values ​​in the symbol set of each structural region and the pixel order variation of each structural region.

6. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining the center point is as follows: corner point detection is performed on each structural region, and the average value of the pixel positions of all corner points in each structural region is taken as the center point of each structural region.

7. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for calculating the corner point distribution difference of each structural region is as follows: ； In the formula, The corner point distribution difference of the i-th structural region; Let be the number of all corner points in the i-th structural region; The mean of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; Let V be the variance of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; This is a preset constant.

8. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining the structural distribution distance of each region with the same structural type is as follows: The Euclidean distance between any two corner points in the same structural region is calculated, and the square root of the sum of the squares of the maximum and minimum Euclidean distances is taken to obtain the structural distribution distance of each same structural region.

9. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for calculating the search step size of the same structural region for each type of structure is as follows: ； In the formula, Let be the search step size for the same structural region of the j-th structure; The mean pixel disorder of all structural regions in the same structural region of the j-th structure; The mean of the structural distribution distances of all structural regions within the same structural region of the j-th structure; It represents the maximum Euclidean distance between any two corner points in all structural regions; To find the summation normalization function; This is the rounding function.

10. A circuit etching apparatus for thermally printed wafers, the apparatus storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the line etching method for a thermal printed sheet as described in any one of claims 1-9.

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