Calibration method for sub-pixel micro-scanning vibration splicing and application thereof

Abstract

The invention provides a sub-pixel micro-scanning vibration splicing calibration method and application thereof. The method comprises the following steps: S1, acquiring a plurality of images of sub-pixel light spots respectively moving to a plurality of different sub-regions; s2, for each sub-region, determining a real coordinate of a sub-pixel light spot in each image corresponding to each sub-region; s3, according to the real coordinates corresponding to all the sub-areas and the theoretical coordinates of the sub-areas, whether a preset convergence condition is met or not is judged, and if the judgment result is yes, the calibrated photocuring type 3D printing equipment is obtained; if not, continuing to execute the step S4; s4, performing polynomial regression analysis on all the corresponding real coordinates and theoretical coordinates of each sub-region to obtain a corresponding vibration zooming ratio of the sub-pixel light spot in the sub-region; and S5, adjusting the corresponding position coordinate data according to the vibration zooming multiplying power corresponding to each sub-region, and continuing to execute the step S1.

Description

Technical Field

[0001] This application mainly relates to the field of sub - pixel micro - scanning technology, and particularly relates to a calibration method and application for sub - pixel micro - scanning vibration stitching. Background Art

[0002] In the field of stereolithography 3D printing, sub - pixel micro - scanning technology greatly improves the forming resolution through fine vibration stitching. However, there are deviations between the vibration positions of different devices and the ideal values, resulting in forming defects of the ultimate size features. Currently, the adjustment of vibration positions mainly relies on the subjective evaluation of printed products, making it difficult to ensure its accuracy and consistency. This affects the application effect of sub - pixel micro - scanning technology in high - precision manufacturing. Summary of the Invention

[0003] The technical problem to be solved by this application is to provide a calibration method and application for sub - pixel micro - scanning vibration stitching, which can automatically correct the deviation between the vibration position and the ideal value to improve the printing accuracy.

[0004] To solve the above - mentioned technical problem, this application provides a calibration method for sub - pixel micro - scanning vibration stitching, which is applied to a stereolithography 3D printing device. The stereolithography 3D printing device is adapted to generate sub - pixel light spots and cure photosensitive objects within the corresponding physical pixel regions with the sub - pixel light spots. The stereolithography 3D printing device includes a vibration mechanism, and the vibration mechanism is used to control the sub - pixel light spot corresponding to the physical pixel region to move to the sub - region according to the position coordinate data of the sub - region within the physical pixel region. The method includes: Step S1: Obtain multiple images of the sub - pixel light spot moving to multiple different sub - regions respectively; Step S2: For each sub - region, determine the true coordinates of the sub - pixel light spot in the corresponding images; Step S3: According to the true coordinates corresponding to each sub - region and the theoretical coordinates of the sub - region, determine whether the preset convergence condition is reached. If the judgment result is yes, obtain the calibrated stereolithography 3D printing device; if the judgment result is no, continue to execute Step S4; Step S4: For each sub - region, perform polynomial regression analysis on all the corresponding true coordinates and theoretical coordinates to obtain the vibration scaling factor of the sub - pixel light spot corresponding to the sub - region; Step S5: Adjust the corresponding position coordinate data according to the vibration scaling factor corresponding to each sub - region, and continue to execute Step S1.

[0005] Optionally, the ratio of the size of the sub - pixel light spot to the size of the physical pixel region is 1:N, where N is greater than 1; the ratio of the size of each sub - region to the size of the physical pixel region is 1:M, where M is greater than 1 and M is less than or equal to N.

[0006] Optionally, when the center distance between two adjacent physical pixel regions is a fixed value, a coordinate system is constructed based on the centers of the physical pixel regions, and the center distance is divided into K equal parts with each equal part serving as the minimum unit scale of the coordinate system. According to the relative position of the sub-region in the physical pixel region, the coordinates of the center of the sub-region in the coordinate system are obtained as the theoretical coordinates, where K is an integer multiple of M.

[0007] Optionally, the theoretical coordinates of the sub-region are used as the initial position coordinate data corresponding to the sub-region.

[0008] Optionally, in step S1, an image is acquired by a CCD camera.

[0009] Optionally, in step S2, the true coordinates C of the sub-pixel light spot in the image B corresponding to the sub-region A are determined through the following steps: the pixel region corresponding to the sub-pixel light spot is extracted from the image B; the true coordinates C are determined according to the pixel region.

[0010] Optionally, before extracting the pixel region corresponding to the sub-pixel light spot from the image B, it further includes: performing image noise reduction on the image B.

[0011] Optionally, the step of determining the true coordinates C according to the pixel region includes: calculating the weighted average of the coordinates of each pixel in the pixel region and the corresponding weights to obtain the corresponding true coordinates C, where the weights corresponding to the pixels are obtained according to the gray levels of the pixels.

[0012] Optionally, the preset convergence condition is that for each sub-region, the deviations between the corresponding at least one true coordinate and the corresponding theoretical coordinate are all within the preset deviation range.

[0013] Optionally, in step S4, the vibration scaling factor D of the sub-pixel light spot corresponding to the sub-region A is obtained through the following steps: at least one fitting coordinate is determined according to all the true coordinates corresponding to the sub-region A; at least one fitting coordinate is fitted to the theoretical coordinates of the sub-region A through polynomial regression analysis, and the coefficients of the fitted polynomial are used as the vibration scaling factor.

[0014] Optionally, when the polynomial regression analysis is a first-order polynomial regression analysis, the average value of all the true coordinates corresponding to the sub-region A is used as the fitting coordinate; the vibration scaling factor includes the first-order component x in the x direction ′ and the first-order component y in the y direction ′ , and its calculation expression is: In the formula, x1 is the value of the true coordinate in the x direction, y1 is the value of the true coordinate in the y direction, x2 is the value of the fitting coordinate in the x direction, and y2 is the value of the fitting coordinate in the y direction.

[0015] Optionally, when the polynomial regression analysis is a multiple polynomial regression analysis, all the true coordinates corresponding to the sub-region A are clustered to generate multiple coordinates for fitting.

[0016] Optionally, before determining at least one coordinate for fitting according to all the true coordinates corresponding to the sub-region A, it further includes: eliminating the abnormal true coordinates among all the true coordinates through data cleaning.

[0017] To solve the above technical problems, the present application provides a light-curing 3D printing device, which is suitable for generating a sub-pixel light spot and curing a photosensitive object in a corresponding physical pixel region with the sub-pixel light spot, including: a vibration mechanism configured to control the sub-pixel light spot corresponding to a physical pixel region to move to a sub-region according to the position coordinate data of the sub-region in the physical pixel region; and a host computer, which includes a memory and a processor. The memory is used to store instructions executable by the processor, and the processor is used to execute the instructions to implement the above calibration method for sub-pixel micro-scanning vibration stitching.

[0018] To solve the above technical problems, the present application provides a computer-readable medium storing computer program code, and the computer program code implements the above calibration method for sub-pixel micro-scanning vibration stitching when executed by a processor.

[0019] Compared with the prior art, the present application has the following advantages: The calibration method for sub-pixel micro-scanning vibration stitching and its application in the present application can obtain the true coordinates of the sub-pixel light spot in each sub-region, perform regression analysis on them with the theoretical coordinates of the corresponding sub-region, so as to adjust the position coordinate data corresponding to the sub-region to correct the position deviation generated when the vibration mechanism controls the sub-pixel light spot to move to the sub-region; by presetting the convergence condition, iterating the position coordinate data of each sub-region multiple times, so as to continuously reduce the position deviation to achieve precise control of the movement of the sub-pixel light spot when there are fluctuations and deviations that cannot be overcome by the hardware of the vibration mechanism; for a sub-pixel light spot with a specified size, by setting the size of the sub-region to be larger than the sub-pixel light spot and using methods such as curve fitting, while reducing the calculation amount of the calibration process, ensuring precise control of the movement of the sub-pixel light spot. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Including the drawings is to provide a further understanding of the present application. They are incorporated and constitute a part of the present application. The drawings illustrate embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the drawings:

[0021] Figure 1 is a device block diagram of a light-curing 3D printing device according to an embodiment of the present application;

[0022] Figure 2Schematic diagram of a physical pixel region and its sub-regions according to an embodiment of the present application;

[0023] Figure 3 Flowchart of a calibration method for sub-pixel micro-scanning vibration mosaicking according to an embodiment of the present application;

[0024] Figure 4 Image containing sub-pixel light spots according to an embodiment of the present application;

[0025] Figure 5 Flowchart of determining the true coordinates C of sub-pixel light spots in image B corresponding to sub-region A according to an embodiment of the present application;

[0026] Figure 6 Schematic diagram of a pixel region according to an embodiment of the present application;

[0027] Figure 7 Flowchart of obtaining the vibration scaling ratio D of sub-pixel light spots corresponding to sub-region A according to an embodiment of the present application;

[0028] Figure 8 Schematic diagram of the fitting coordinates and theoretical coordinates before correction according to an embodiment of the present application; and

[0029] Figure 9 Schematic diagram of the fitting coordinates and theoretical coordinates after correction according to an embodiment of the present application. Detailed implementation manners

[0030] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the figures represent the same structure or operation.

[0031] As shown in the present application and the claims, unless the context clearly indicates an exception, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0032] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0033] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc., are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0034] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above", etc. may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientation of "above..." and "below...". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used herein.

[0035] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is merely for the convenience of differentiating the corresponding components. Without additional statements, these terms have no special meanings, and thus should not be construed as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meanings implied by each term.

[0036] It should be understood that when a component is referred to as "on another component", "connected to another component", "coupled to another component", or "in contact with another component", it can be directly on, connected to, or coupled to, or in contact with the other component, or there may be an intervening component. In contrast, when a component is referred to as "directly on another component", "directly connected to", "directly coupled to", or "directly in contact with" another component, there is no intervening component. Similarly, when a first component is referred to as "electrically contacting" or "electrically coupled to" a second component, there is an electrical path allowing current to flow between the first component and the second component. The electrical path may include capacitors, coupled inductors, and / or other components allowing current to flow, even if there is no direct contact between the conductive components.

[0037] Flowcharts are used in this application to illustrate the operations performed by the systems according to the embodiments of this application. It should be understood that the operations before or below may not necessarily be executed precisely in sequence. Instead, various steps may be executed in reverse order or simultaneously. Also, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0038] Figure 1 is a block diagram of a photocurable 3D printing device according to an embodiment of this application. As Figure 1As shown, the light-curing 3D printing device 100 includes a vibration mechanism 11 and a host computer 12. The light-curing 3D printing device 100 is adapted to generate a sub-pixel light spot through sub-pixel micro-scanning technology and cure a photosensitive object within a corresponding physical pixel region with the sub-pixel light spot to achieve light-curing 3D printing. Regarding the sub-pixel micro-scanning technology (SMS, Subpixel Micro Scanning), reference can be made to the Chinese patent with the publication number CN104669619A, and all the content in this patent can be used to illustrate the sub-pixel micro-scanning technology in this application. It should be noted that the photosensitive object, physical pixel region, and sub-pixel light spot in this application all have other names in CN104669619A. Here, in combination with part of the description of an embodiment in CN104669619A: "For example, the ratio of the size of the converged light spot (the size of the image 501a projected on the surface of the photosensitive material) to the pixel size (the size of the liquid crystal pixel projected on the surface of the photosensitive material) can be 1:2, that is, the area ratio is 1:4, and the brightness of the light spot is correspondingly increased to 4 times the original." An exemplary illustration is as follows: "photosensitive material" is the "photosensitive object" in this application, "light spot" is the "sub-pixel light spot" in this application, and "pixel" is the "physical pixel region" in this application.

[0039] Continue to refer to Figure 1 , the vibration mechanism 11 is configured to control the sub-pixel light spot of the corresponding physical pixel region to move to the sub-region according to the position coordinate data of the sub-region in the physical pixel region. Then, the vibration mechanism 11 controls the sub-pixel light spot to move in the specified sub-region, and the process of curing at least part of the photosensitive object in the physical pixel region with the sub-pixel light spot is the vibration splicing. Preferably, the ratio of the size of the sub-pixel light spot to the size of the physical pixel region is 1:N, where N is greater than 1; the ratio of the size of each sub-region to the size of the physical pixel region is 1:M, where M is greater than 1 and M is less than or equal to N. Further, when the center distance between two adjacent physical pixel regions is a fixed value, a coordinate system is constructed based on the center of the physical pixel region, and the center distance is divided into K equal parts, and each equal part is used as the minimum unit scale of the coordinate system. According to the relative position of the sub-region in the physical pixel region, the coordinates of the center of the sub-region in the coordinate system are obtained as the theoretical coordinates. Further, the theoretical coordinates of the sub-region are used as the initial position coordinate data corresponding to the sub-region.

[0040] To better explain the concepts of physical pixel region, sub-region, sub-pixel light spot, and theoretical coordinates, the following refers to Figure 2 for exemplary illustration. Figure 2 is a schematic diagram of the physical pixel region and its sub-regions. As shown in Figure 2As shown, the shape of the physical pixel region is a rectangle, and both the length and width of this rectangle are 10 units, that is, the physical pixel region is a 10*10 rectangle. The same content will not be repeated hereinafter. Exemplarily, the units of the length and width of the rectangle corresponding to the physical pixel region are μm. Continuing to refer to Figure 2 , each physical pixel region is arranged adjacent to each other in sequence. When M = 2, a physical pixel region is evenly divided into 4 sub-regions, and each sub-region is a 5*5 rectangle. When N = 2, the sub-pixel light spot has the Figure 2 same shape as the sub-region, which is also a 5*5 rectangle. It should be noted that according to the Figure 2 exemplary descriptions of the physical pixel region, sub-region, and sub-pixel light spot, the size of the sub-pixel light spot, the size of the physical pixel region, and the size of the sub-region are all the side lengths of the corresponding rectangles. Continuing to refer to Figure 2 , when K = 4, and with the Figure 2 lower left right-angled side of the lower left physical pixel region in to construct a coordinate system (including the origin o, the x-axis, and the y-axis), the theoretical coordinates of sub-region a are (2.5, 17.5). It should be noted that in this embodiment, the center of the rectangle is set as the point corresponding to the theoretical coordinates, that is, the coordinate point. Therefore, K takes an integer multiple of 2M to obtain accurate coordinate points; in other embodiments, if the vertex of the rectangle is used as the coordinate point, K can take an integer multiple of M. It should also be noted that due to the performance of the light-curing 3D printing device 100, when the physical pixel region is a rectangle, the shape of the sub-pixel light spot is not necessarily a standard rectangle, and it can also be a circle, etc. In addition, each sub-pixel light spot corresponds to a different physical pixel region, and the sub-pixel light spot only moves to each sub-region of the corresponding physical pixel region.

[0041] Continuing to refer to Figure 1 , since the size of the sub-pixel light spot is smaller than the physical pixel region, the accuracy that the hardware of the vibration mechanism 11 can achieve cannot accurately control the movement of the sub-pixel light spot according to the initial position coordinate data. Therefore, it is necessary to adjust the position coordinate data through the calibration method of sub-pixel micro-scanning vibration stitching to improve the movement accuracy of the sub-pixel light spot. Specifically, the host computer 12 includes a memory 121 and a processor 122. The memory 121 is used to store instructions that can be executed by the processor 122. The processor 122 is used to execute the instructions to implement the calibration method of sub-pixel micro-scanning vibration stitching.

[0042] The light-curing 3D printing device 100 of the present application can calibrate the light-curing 3D printing device 100 by executing the calibration method of sub-pixel micro-scanning vibration stitching proposed in the present application, and reduce the movement deviation of the sub-pixel light spot. The calibration method of sub-pixel micro-scanning vibration stitching will be described below.

[0043] Figure 3is a flowchart of a calibration method for sub-pixel micro-scanning vibration mosaicking according to an embodiment of the present application. Exemplarily, the calibration method 200 for sub-pixel micro-scanning vibration mosaicking can be executed by a light-curing 3D printing device 100 as shown in Figure 1 shown. As shown in Figure 3 shown, the calibration method 200 for sub-pixel micro-scanning vibration mosaicking includes the following steps.

[0044] First, step S1 is to obtain multiple images of the sub-pixel light spot moving to multiple different sub-regions. Preferably, in step S1, images are obtained by a CCD camera because, compared with an ordinary camera with a lens, the images obtained by the CCD camera have no distortion, so that the position information of the sub-pixel light spot can be obtained more accurately. Exemplarily, referring to Figure 4 , Figure 4 shows an image that includes a black background and 9 white pixel regions, and each white pixel region is the position where the sub-pixel light spot is located when it moves to the corresponding sub-region. It should be noted that an image may only contain one white pixel region, that is, after the vibration mechanism 11 controls the sub-pixel light spot to move to a sub-region, the corresponding image is obtained, or it may contain multiple white pixel regions, that is, the vibration mechanism 11 controls the sub-pixel light spot to move to multiple sub-regions respectively and obtains the corresponding images. In addition, in order to reduce the interference of the external environment on the calibration process, preferably, multiple images are obtained for each sub-region. For example, the vibration mechanism 11 controls the sub-pixel light spot to move to a sub-region 100 times, and 100 corresponding images are obtained. Each image contains the position information of the sub-pixel light spot to this sub-region once.

[0045] Continuing to refer to Figure 3 , step S2 is to determine the true coordinates of the sub-pixel light spot in each corresponding image for each sub-region. The following refers to Figure 5 to illustrate the specific sub-steps of determining the true coordinates C of the sub-pixel light spot in image B corresponding to sub-region A through step S2.

[0046] Step S21 is to perform image noise reduction on image B. Optionally, the image noise reduction in step S21 includes smoothing image B through a smoothing convolution kernel to avoid taking interference pixel points as sub-pixel light spots subsequently.

[0047] Step S22 is to extract the pixel region corresponding to the sub-pixel light spot from image B. Optionally, by setting a pixel gray threshold, all pixels in image B that are lower than the pixel gray threshold are set to black, that is, the background color, so that each white pixel region corresponding to the sub-pixel light spot in image B forms non-connected islands, that is, pixel regions, to avoid extracting the connected white pixel regions as a whole in the original image B. Exemplarily, Figure 6The area other than the black background is a pixel area extracted through step S22.

[0048] Step S23 is to determine the true coordinate C according to the pixel area. Preferably, in step S23, the coordinates of each pixel in the pixel area are calculated with the corresponding weights to obtain the corresponding true coordinate C, where the weights corresponding to the pixels are obtained according to the gray levels of the pixels. Compared with selecting the brightest pixel point as the true coordinate C, the above weighted average calculation can comprehensively consider the gray levels, i.e., the brightness states, of each pixel in the pixel area, so as to select a more accurate true coordinate C.

[0049] Continue to refer to Figure 3 , step S3 is to determine whether the preset convergence condition is met according to the true coordinates corresponding to each sub-region and the theoretical coordinates of the sub-region. If the judgment result is yes, the calibrated stereolithography 3D printing device is obtained; if the judgment result is no, step S4 is continued. Preferably, the preset convergence condition is that for each sub-region, the deviations between at least one corresponding true coordinate and the corresponding theoretical coordinate are all within the preset deviation range. Step S4 is to perform polynomial regression analysis on all the true coordinates corresponding to each sub-region and the theoretical coordinates to obtain the vibration scaling factor of the sub-pixel light spot corresponding to the sub-region. The following refers to Figure 7 , and the specific sub-steps for obtaining the vibration scaling factor D of the sub-pixel light spot corresponding to sub-region A through step S4 are described.

[0050] Step S41 is to eliminate the abnormal true coordinates in all the true coordinates through data cleaning. Exemplarily, the deviation values between each true coordinate and the theoretical coordinate are calculated, and the deviation values are sorted from small to large. When the true coordinates corresponding to the deviation values in the last 5% that are greater than twice the average value of the deviation values in the first 95% are used as the abnormal true coordinates, the influence of abnormal situations such as dust influence and lens defects on the data is removed.

[0051] Step S42 is to determine at least one fitting coordinate according to all the true coordinates corresponding to sub-region A. Step S43 is to fit at least one fitting coordinate to the theoretical coordinate of sub-region A through polynomial regression analysis, and use the coefficients of the fitted polynomial as the vibration scaling factor. Preferably, when the polynomial regression analysis is multiple polynomial regression analysis, all the true coordinates corresponding to sub-region A are clustered to generate multiple fitting coordinates. It should be noted that the highest degree of the multiple polynomial is preferably 3-4 times to avoid overfitting. Preferably, when the polynomial regression analysis is single polynomial regression analysis, the average value of all the true coordinates corresponding to sub-region A is used as the fitting coordinate. The vibration scaling factor includes the first-order component x ′ in the x direction and the first-order component y ′ in the y direction, and its calculation expression is:

[0052]

[0053] Where x1 is the value of the true coordinate in the x direction, y1 is the value of the true coordinate in the y direction, x2 is the value of the coordinate for fitting in the x direction, and y2 is the value of the coordinate for fitting in the y direction.

[0054] Continue to refer to Figure 3 , step S5 is to adjust the corresponding position coordinate data according to the vibration scaling factor corresponding to each sub-region, and continue to execute step S1. It should be noted that when the deviation between the true coordinate of the sub-pixel light spot in a sub-region and the theoretical coordinate of the sub-region is within the preset deviation range, if the deviation of at least one other sub-region is still outside the preset deviation range, all sub-regions will adjust the position coordinate data according to the corresponding vibration scaling factor.

[0055] To better understand the technical solutions described in the above embodiments of the present application, the following systematically describes the detailed steps of a calibration method 200 for sub-pixel micro-scanning vibration stitching of a stereolithography 3D printing device 100 of the present application. First, project a checkerboard pattern and use a CCD camera to collect images. Secondly, use an image processing algorithm to perform feature recognition on the images and record the actual positions of each scanning point (i.e., the true coordinates of the sub-pixel light spots). Then, compare the actual positions with the theoretical positions (i.e., the theoretical coordinates of the sub-regions), and use a binary linear polynomial for regression analysis to calculate the vibration scaling factor. Subsequently, adjust the vibration positions (i.e., the position coordinate data) according to the calculation results, and repeat the above steps for iterative correction. Finally, when the coefficient of the first-order term reaches the preset convergence threshold, the calibration process is completed, and the calibrated stereolithography 3D printing device 100 is obtained. Exemplarily, refer to Figure 8 and Figure 9 , Figure 8 are schematic diagrams of the coordinates for fitting and the theoretical coordinates when multiple images are respectively obtained for each sub-region in a physical pixel region before correction of the stereolithography 3D printing device 100. Figure 9 are schematic diagrams of the coordinates for fitting and the theoretical coordinates when multiple images are respectively obtained for each sub-region in this physical pixel region after iterative correction by the calibration method 200 of sub-pixel micro-scanning vibration stitching of the stereolithography 3D printing device 100. It should be noted that Figure 8 and Figure 9 are schematic diagrams of the adjustment of the position coordinate data for each sub-region in a physical pixel region. The parameter M = 8 corresponding to the sub-region means that this physical pixel region has 8 * 8 = 64 sub-regions, and the parameter N = 8 corresponding to the sub-pixel light spot in this physical pixel region. Figure 8 and Figure 9Among them, each rectangular box represents the fitting coordinates corresponding to each sub-region, and the fitting coordinates are the average values of all the corresponding real coordinates. Each cross mark represents the theoretical coordinates corresponding to each sub-region. In Figure 9 Among them, each rectangular block basically coincides with the cross mark. Thus, it can be seen that the calibration method 200 of sub-pixel micro-scanning vibration stitching can accurately correct the movement of the sub-pixel light spot controlled by the vibration mechanism 11.

[0056] It should be noted that since the physical pixel region has a fixed size and arrangement position, and each sub-pixel light spot generated by the sub-pixel micro-scanning technology has the same initial relative position with the corresponding physical pixel region, the calibration method 200 of sub-pixel micro-scanning vibration stitching can calibrate the entire light-curing 3D printing device 100 by adjusting the position coordinate data corresponding to each position of a sub-pixel light spot, that is, there is no need to separately adjust the position coordinate data of each sub-pixel light spot. In addition, when M is less than N, the vibration mechanism 11 controls the sub-pixel light spot with a size of to move in the M×M sub-regions (the size of this sub-region is ) of the physical pixel region, and corrects the position coordinate data corresponding to the M×M sub-regions. After obtaining the calibrated light-curing 3D printing device 100, the light-curing 3D printing device 100 calculates the position coordinate data corresponding to the N×N sub-regions (the size of this sub-region is ) of the physical pixel region according to the corrected position coordinate data corresponding to the M×M sub-regions, so as to complete the accurate calibration of the light-curing 3D printing device 100 through fewer sub-regions and reduce the calculation amount in the calibration process. Exemplarily, fit the curve according to the theoretical coordinates and the position coordinate data after iterative correction of the M sub-regions (the size of this sub-region is ) in the same row or column, and then select the corresponding value from this curve as the position coordinate data according to the theoretical coordinates of the N sub-regions (the size of this sub-region is ) in this row or this column, so that the vibration mechanism 11 can control the sub-pixel light spot to move to the specified sub-region (the size of this sub-region is ) according to the selected position coordinate data.

[0057] On the other hand, this application also includes a computer-readable medium storing computer program code, and the computer program code realizes the calibration method of sub-pixel micro-scanning vibration stitching described above when executed by a processor.

[0058] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only for illustration and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0059] Meanwhile, this application uses specific terms to describe the embodiments of this application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0060] Some aspects of this application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software can all be referred to as "data blocks", "modules", "engines", "units", "components", or "systems". The processor can be one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. In addition, aspects of this application may be embodied as a computer product located in one or more computer readable media, which includes computer readable program codes. For example, the computer readable media may include, but is not limited to, magnetic storage devices (such as hard disks, floppy disks, magnetic tapes...), optical disks (such as compact disks CD, digital versatile disks DVD...), smart cards, and flash memory devices (such as cards, sticks, key drives...).

[0061] The computer readable media may contain a propagated data signal containing computer program codes, such as on a baseband or as part of a carrier wave. The propagated signal may have various forms of representation, including electromagnetic form, optical form, etc., or a suitable combination of forms. The computer readable media can be any computer readable media other than computer readable storage media, which can be connected to an instruction execution system, apparatus, or device to achieve communication, propagation, or transmission for use of the program. The program codes located on the computer readable media can be propagated through any suitable media, including radio, cable, fiber optic cable, radio frequency signal, or similar media, or any combination of the above media.

[0062] Similarly, it should be noted that, in order to simplify the description disclosed in this application and thus help the understanding of one or more embodiments of the application, in the foregoing description of the embodiments of this application, multiple features are sometimes merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than those mentioned in the claims. In fact, the features of the embodiments are fewer than all the features of the single embodiment disclosed above.

[0063] In some embodiments, numbers are used to describe components and the quantity of attributes. It should be understood that such numbers used for the description of embodiments are modified by the modifiers "about", "approximate" or "substantially" in some examples. Unless otherwise stated, "about", "approximate" or "substantially" indicate that the said numbers allow a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, and such approximate values may change according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used in some embodiments of this application to confirm the breadth of their scope are approximate values, in specific embodiments, the setting of such numerical values is as precise as possible within the feasible range.

[0064] Although this application has been described with reference to the current specific embodiments, those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate this application, and various equivalent changes or substitutions can be made without departing from the spirit of this application. Therefore, as long as the changes and modifications of the above embodiments are within the scope of the spirit of this application, they will fall within the scope of the claims of this application.

Claims

1. A calibration method for sub-pixel micro-scanning vibration stitching, characterized in that, Applied to a photocuring 3D printing device, the photocuring 3D printing device is adapted to generate sub-pixel light spots and cure the photosensitive object within the corresponding physical pixel region with the sub-pixel light spots. The photocuring 3D printing device includes a vibration mechanism, and the vibration mechanism is used to control the sub-pixel light spot corresponding to the physical pixel region to move to the sub-region according to the position coordinate data of the sub-region within the physical pixel region. The method includes: Step S1: Obtain multiple images of the sub-pixel light spot moving to multiple different sub-regions respectively; Step S2: For each sub-region, determine the true coordinates of the sub-pixel light spot in the corresponding image; Step S3: According to the true coordinates corresponding to each sub-region and the theoretical coordinates of the sub-region, determine whether the preset convergence condition is met. If the judgment result is yes, obtain the calibrated photocuring 3D printing device; if the judgment result is no, continue to execute Step S4; Step S4: For each sub-region, perform polynomial regression analysis on all the corresponding true coordinates and the theoretical coordinates to obtain the vibration scaling factor corresponding to the sub-pixel light spot in the sub-region; Step S5: Adjust the corresponding position coordinate data according to the vibration scaling factor corresponding to each sub-region, and continue to execute Step S1.

2. The calibration method for sub-pixel micro-scanning vibration mosaicing according to claim 1, wherein, The ratio of the size of the sub-pixel light spot to the size of the physical pixel region is 1:N, where N is greater than 1; The ratio of the size of each sub-region to the size of the physical pixel region is 1:M, where M is greater than 1 and M is less than or equal to N.

3. The calibration method for sub-pixel micro-scanning vibration mosaicing according to claim 2, wherein It further includes that when the center distance between two adjacent physical pixel regions is a fixed value, a coordinate system is constructed based on the center of the physical pixel region, and the center distance is divided into K equal parts and each equal part is used as the minimum unit scale of the coordinate system. According to the relative position of the sub-region in the physical pixel region, the coordinates of the center of the sub-region in the coordinate system are obtained as the theoretical coordinates, where K is an integer multiple of M.

4. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 3, wherein, Use the theoretical coordinates of the sub-region as the initial position coordinate data corresponding to the sub-region.

5. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 1, characterized in that It further includes obtaining the image by a CCD camera in Step S1.

6. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 1, characterized in that In Step S2, the true coordinates C of the sub-pixel light spot in the image B corresponding to the sub-region A are determined through the following steps: Extract the pixel region corresponding to the sub-pixel light spot from the image B; Determine the true coordinates C according to the pixel region.

7. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 6, characterized in that Before extracting the pixel region corresponding to the sub-pixel light spot from the image B, it further includes: performing image denoising on the image B.

8. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 6, characterized in that The step of determining the true coordinates C according to the pixel region includes: calculating the weighted average of the coordinates of each pixel in the pixel region and the corresponding weights to obtain the corresponding true coordinates C, where the weight corresponding to the pixel is obtained according to the gray level of the pixel.

9. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 1, wherein The preset convergence condition is that for each sub-region, the deviation between at least one of the corresponding true coordinates and the corresponding theoretical coordinates is within the preset deviation range.

10. The calibration method for sub-pixel micro-scanning vibration mosaicking according to any one of claims 1-9, characterized in that, In step S4, the vibration scaling factor D corresponding to the sub-pixel light spot in sub-region A is obtained through the following steps: Determine at least one fitting coordinate based on all the true coordinates corresponding to sub-region A; Fit the at least one fitting coordinate to the theoretical coordinate of sub-region A through polynomial regression analysis, and use the coefficients of the fitted polynomial as the vibration scaling factor.

11. The calibration method for sub-pixel micro-scanning vibration stitching according to claim 10, characterized in that, When the polynomial regression analysis is a first-degree polynomial regression analysis, use the average value of all the true coordinates corresponding to sub-region A as the fitting coordinate; The vibration scaling factor includes the first-order component x in the x direction ′ and the first-order component y in the y direction ′ , and its calculation expression is: In the formula, x1 is the value of the true coordinate in the x direction, y1 is the value of the true coordinate in the y direction, x2 is the value of the fitting coordinate in the x direction, and y2 is the value of the fitting coordinate in the y direction.

12. The calibration method for sub-pixel micro-scanning vibration mosaicking according to claim 10, characterized in that, When the polynomial regression analysis is a multi-degree polynomial regression analysis, cluster all the true coordinates corresponding to sub-region A to generate multiple fitting coordinates.

13. The calibration method for sub-pixel micro-scanning vibration mosaicing according to claim 10, characterized in that, Before determining at least one fitting coordinate based on all the true coordinates corresponding to sub-region A, it further includes: eliminating the abnormal true coordinates among all the true coordinates through data cleaning.

14. A photocurable 3D printing device, characterized in that, Suitable for generating a sub-pixel light spot and curing the photosensitive object in the corresponding physical pixel region with the sub-pixel light spot, including: A vibration mechanism configured to control the sub-pixel light spot corresponding to the physical pixel region to move to the sub-region according to the position coordinate data of the sub-region in the physical pixel region; and A host computer, The host computer includes a memory and a processor, The memory is used to store instructions executable by the processor, The processor is used to execute the instructions to implement the calibration method of sub-pixel micro-scanning vibration stitching as described in any one of claims 1-13.

15. A computer-readable medium storing computer program code, the computer program code implementing the calibration method of sub-pixel micro-scanning vibration stitching as described in any one of claims 1-13 when executed by a processor.

Images