Calibration method for sub-pixel micro-scanning vibration stitching and the use thereof
Patent Information
- Application Number
- PCT/CN2025/125148
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-17
- Filing Date
- 2025-09-29
- Publication Date
- 2026-09-24
Smart Images
Figure CN2025125148_24092026_PF_FP_ABST
Abstract
Description
Calibration method and application of subpixel microscanning vibration stitching Technical Field
[0001] This application mainly relates to the field of subpixel microscanning technology, and in particular to a calibration method for subpixel microscanning vibration splicing and its application. Background Technology
[0002] In the field of photopolymer 3D printing, subpixel micro-scanning technology significantly improves the forming resolution through precise vibration stitching. However, deviations between the vibration positions of different components and the ideal values lead to forming defects in the limiting dimensional features. Currently, the adjustment of vibration positions mainly relies on subjective evaluation of the printed product, making it difficult to guarantee its accuracy and consistency. This affects the application effect of subpixel 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 for subpixel micro-scanning vibration splicing and its application, which can automatically correct the deviation between the vibration position and the ideal value to improve printing accuracy.
[0004] To address the aforementioned technical problems, this application provides a calibration method for sub-pixel micro-scanning vibration stitching, applied to a photopolymerization 3D printing device. The photopolymerization 3D printing device is suitable for generating sub-pixel light spots and solidifying photosensitive objects within corresponding physical pixel regions using these sub-pixel light spots. The photopolymerization 3D printing device includes a vibration mechanism, which controls the movement of the sub-pixel light spot to the corresponding sub-region based on the position coordinate data of the sub-region within the physical pixel region. The method includes: Step S1: Acquiring multiple images of the sub-pixel light spot moving to multiple different sub-regions; Step S2: For each sub-region... Step S3: Determine the true coordinates of the sub-pixel spot in each corresponding image; Step S4: Based on the true coordinates and theoretical coordinates of each sub-region, determine whether the preset convergence condition has been met. If the result is yes, the calibrated photopolymerization 3D printing device is obtained; otherwise, continue to step S4; Step S5: For each sub-region, perform multinomial regression analysis on all the corresponding true coordinates and theoretical coordinates to obtain the vibration scaling factor of the sub-pixel spot in the sub-region; Step S6: Adjust the corresponding position coordinate data according to the vibration scaling factor of each sub-region, and continue to execute step S1.
[0005] Optionally, the ratio of the size of the subpixel 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 center of the physical pixel region, and the center distance is divided into K equal parts, with each part as the smallest unit scale of the coordinate system. Based on 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 theoretical coordinates, where K is an integer multiple of M.
[0007] Optionally, the theoretical coordinates of the sub-region can be used as the initial position coordinate data corresponding to the sub-region.
[0008] Optionally, in step S1, an image is acquired using a CCD camera.
[0009] Optionally, in step S2, the true coordinates C of the sub-pixel spot in image B corresponding to sub-region A are determined by the following steps: extracting the pixel region corresponding to the sub-pixel spot from image B; and determining the true coordinates C based on the pixel region.
[0010] Optionally, before extracting the pixel region corresponding to the sub-pixel spot from image B, the method further includes: image denoising of image B.
[0011] Optionally, the step of determining the true coordinates C based on the pixel region includes: calculating the weighted average of the coordinates of each pixel in the pixel region with its corresponding weight to obtain the corresponding true coordinates C, wherein the weight of the pixel is obtained based on the gray level of the pixel.
[0012] Optionally, the preset convergence condition is that for each sub-region, the deviation between at least one true coordinate and the corresponding theoretical coordinate is within a preset deviation range.
[0013] Optionally, in step S4, the vibration scaling factor D corresponding to the sub-pixel spot in sub-region A is obtained through the following steps: determining at least one fitting coordinate based on all the true coordinates corresponding to sub-region A; fitting the at least one fitting coordinate to the theoretical coordinates of sub-region A through polynomial regression analysis, and using the coefficients of the fitted polynomial as the vibration scaling factor.
[0014] Optionally, when the polynomial regression analysis is a first-order polynomial regression analysis, the average value of all true coordinates corresponding to sub-region A is used as the fitting coordinates; 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 multinomial regression analysis is a multiple multinomial regression analysis, all the true coordinates corresponding to sub-region A are clustered to generate multiple fitting coordinates.
[0016] Optionally, before determining at least one fitting coordinate based on all the true coordinates corresponding to sub-region A, the method further includes: removing outlier true coordinates from all true coordinates through data cleaning.
[0017] To address the aforementioned technical problems, this application provides a photopolymerization 3D printing device suitable for generating sub-pixel light spots and solidifying photosensitive objects within corresponding physical pixel regions using these sub-pixel light spots. The device includes: a vibration mechanism configured to control the movement of the sub-pixel light spot within a corresponding physical pixel region to the sub-region based on the position coordinate data of the sub-region within the physical pixel region; and a host computer, comprising a memory and a processor. The memory stores instructions executable by the processor, and the processor executes the instructions to implement the aforementioned sub-pixel micro-scanning vibration splicing calibration method.
[0018] To address the aforementioned technical problems, this application provides a computer-readable medium storing computer program code, which, when executed by a processor, implements the aforementioned subpixel micro-scanning vibration stitching calibration method.
[0019] Compared with the prior art, this application has the following advantages: The calibration method and application of subpixel micro-scanning vibration stitching in this application can obtain the real coordinates of the subpixel spot in each sub-region, perform regression analysis with the theoretical coordinates of the corresponding sub-region, and adjust the position coordinate data of the corresponding sub-region to correct the position deviation caused by the vibration mechanism controlling the subpixel spot to move to the sub-region; by setting a convergence condition, the position coordinate data of each sub-region are iterated multiple times to continuously reduce the position deviation, so as to achieve precise control of the subpixel spot movement when the hardware of the vibration mechanism has insurmountable fluctuation deviations; for a subpixel spot of a specified size, by setting the size of the sub-region to be larger than the subpixel spot, and using curve fitting and other methods, the computational load of the calibration process is reduced while ensuring precise control of the subpixel spot movement.
[0020] Overview of the attached figures
[0021] The accompanying drawings are included to provide a further understanding of this application. They are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.
[0022] In the attached image:
[0023] Figure 1 is a block diagram of a photopolymer 3D printing apparatus according to an embodiment of this application;
[0024] Figure 2 is a schematic diagram of a physical pixel region and its sub-regions according to an embodiment of this application;
[0025] Figure 3 is a flowchart of a calibration method for subpixel micro-scanning vibration stitching according to an embodiment of this application;
[0026] Figure 4 is an image containing subpixel light spots according to an embodiment of this application;
[0027] Figure 5 is a flowchart of determining the true coordinates C of the sub-pixel spot in image B corresponding to sub-region A according to an embodiment of this application;
[0028] Figure 6 is a schematic diagram of a pixel region according to an embodiment of the present application;
[0029] Figure 7 is a flowchart of obtaining the vibration scaling factor D of the sub-pixel spot in sub-region A according to an embodiment of the present application;
[0030] Figure 8 is a schematic diagram of the fitting coordinates and theoretical coordinates before correction according to an embodiment of this application; and
[0031] Figure 9 is a schematic diagram of the modified fitting coordinates and theoretical coordinates according to an embodiment of this application.
[0032] Preferred embodiments of the present invention
[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.
[0034] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.
[0035] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.
[0036] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.
[0037] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.
[0038] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.
[0039] 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, coupled to, or in contact with that 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 between the first and second components that allows current to flow. This electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even if there is no direct contact between the conductive components.
[0040] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.
[0041] Figure 1 is a block diagram of a photopolymer 3D printing apparatus according to an embodiment of this application. As shown in Figure 1, the photopolymer 3D printing apparatus 100 includes a vibration mechanism 11 and a host computer 12. This photopolymer 3D printing apparatus 100 is adapted to generate subpixel spots using subpixel microscanning technology, and to solidify the photosensitive object within the corresponding physical pixel area using the subpixel spots, thereby achieving photopolymer 3D printing. For information on subpixel microscanning technology (SMS), please refer to Chinese Patent Publication No. CN104669619A, the entire contents of which can be used to explain the subpixel microscanning technology in this application. It should be noted that the photosensitive object, physical pixel region, and sub-pixel spot in this application are all referred to by other names in CN104669619A. Here, we will refer to a part of the description of an embodiment in CN104669619A: "For example, the ratio of the converged spot size (like the size of 501a projected onto the surface of the photosensitive material) to the pixel size (the size of the liquid crystal pixel projected onto the surface of the photosensitive material) can be 1:2, that is, the area ratio is 1:4, and the spot brightness is correspondingly increased to 4 times the original." For example, "photosensitive material" is the "photosensitive object" of this application, "spot" is the "sub-pixel spot" of this application, and "pixel" is the "physical pixel region" of this application.
[0042] Referring again to Figure 1, the vibration mechanism 11 is configured to control the sub-pixel spot of the corresponding physical pixel region to move to the sub-region based on the position coordinate data of the sub-region within the physical pixel region. The vibration mechanism 11 controls the sub-pixel spot to move within the designated sub-region, enabling the sub-pixel spot to complete the photocuring process on at least a portion of the photosensitive object within the physical pixel region; this is vibration splicing. Preferably, the ratio of the size of the sub-pixel 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, with each part serving as the smallest unit scale of the coordinate system. Based on the relative position of the sub-region within the physical pixel region, the coordinates of the center of the sub-region in the coordinate system are obtained as theoretical coordinates. Further, the theoretical coordinates of the sub-region are used as the initial position coordinate data corresponding to the sub-region.
[0043] To better explain the concepts of physical pixel region, sub-region, sub-pixel spot, and theoretical coordinates, the following illustrative explanation is provided with reference to Figure 2. Figure 2 is a schematic diagram of the physical pixel region and its sub-regions. As shown in Figure 2, the physical pixel region is rectangular, with a length and width of 10 units each, i.e., a 10*10 rectangle. This same concept will not be repeated hereafter. For example, the length and width of the rectangle corresponding to the physical pixel region are in μm. Continuing to refer to Figure 2, the physical pixel regions are arranged sequentially adjacent to each other. 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 spot has the same shape as the sub-region in Figure 2, also a 5*5 rectangle. It should be noted that, according to the illustrative description of the physical pixel region, sub-region, and sub-pixel spot in Figure 2, the size of the sub-pixel spot, the size of the physical pixel region, and the size of the sub-region are all the side lengths of the corresponding rectangles. Referring again to Figure 2, when K = 4, and a coordinate system (including the origin o, x-axis, and y-axis) is constructed using the lower left right-angled side of the physical pixel region in Figure 2, 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, i.e., the coordinate point. Therefore, K is a multiple of 2M to obtain accurate coordinate points. In other embodiments, if the vertices of the rectangle are used as coordinate points, K can be a multiple of M. It should also be noted that due to the performance of the photopolymerization 3D printing equipment 100, when the physical pixel region is rectangular, the shape of the sub-pixel spot is not necessarily a standard rectangle; it can also be circular, etc. Furthermore, each sub-pixel spot corresponds to a different physical pixel region, and the sub-pixel spot only moves to the respective sub-regions of the corresponding physical pixel region.
[0044] Referring again to Figure 1, since the size of the subpixel spot is smaller than the physical pixel area, the hardware of the vibration mechanism 11 cannot accurately control the movement of the subpixel spot based on the initial position coordinate data. Therefore, it is necessary to adjust the position coordinate data through a subpixel micro-scanning vibration stitching calibration method to improve the movement accuracy of the subpixel 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 instructions to implement the subpixel micro-scanning vibration stitching calibration method.
[0045] The photopolymer 3D printing equipment 100 of this application can be calibrated by implementing the subpixel micro-scanning vibration stitching calibration method proposed in this application, thereby reducing the movement deviation of the subpixel spot. The subpixel micro-scanning vibration stitching calibration method will be described below.
[0046] Figure 3 is a flowchart of a calibration method for subpixel micro-scanning vibration stitching according to an embodiment of this application. Exemplarily, this calibration method 200 for subpixel micro-scanning vibration stitching can be performed by the photopolymerization 3D printing equipment 100 shown in Figure 1. As shown in Figure 3, the calibration method 200 for subpixel micro-scanning vibration stitching includes the following steps.
[0047] First, step S1 involves acquiring multiple images of the subpixel spot moving to different sub-regions. Preferably, images are acquired using a CCD camera in step S1 because, compared to a regular camera with a lens, images acquired by a CCD camera are distortion-free, thus enabling more accurate acquisition of the subpixel spot's position information. For example, referring to Figure 4, an image is shown, comprising a black background and nine white pixel regions, each representing the position of the subpixel spot when it moves to its corresponding sub-region. It should be noted that an image may contain only one white pixel region (i.e., the vibration mechanism 11 controls the subpixel spot to move to one sub-region before acquiring the corresponding image), or it may contain multiple white pixel regions (i.e., the vibration mechanism 11 controls the subpixel spot to move to multiple sub-regions and acquires corresponding images). Furthermore, to reduce interference from the external environment during the calibration process, preferably, multiple images are acquired for each sub-region. For example, the vibration mechanism 11 controls the subpixel spot to move to a sub-region 100 times, acquiring 100 corresponding images, each image containing the position information of the subpixel spot to that sub-region once.
[0048] Referring again to Figure 3, step S2 involves determining the true coordinates of the sub-pixel spot in each image corresponding to each sub-region. Referring to Figure 5 below, the specific sub-steps for determining the true coordinates C of the sub-pixel spot in image B corresponding to sub-region A through step S2 will be explained.
[0049] Step S21 involves denoising image B. Optionally, the image denoising in step S21 may include smoothing image B using a smoothing convolution kernel to avoid subsequently treating interfering pixels as subpixel spots.
[0050] Step S22 involves extracting the pixel region corresponding to the sub-pixel spot from image B. Optionally, by setting a pixel grayscale threshold, all pixels in image B below the threshold are set to black (the background color), making the white pixel regions corresponding to the sub-pixel spots in image B form unconnected islands (pixel regions), thus avoiding the extraction of connected white pixel regions as a whole in the original image B. For example, the area outside the black background in Figure 6 is a pixel region extracted through step S22.
[0051] Step S23 involves determining the true coordinates C based on the pixel region. Preferably, in step S23, a weighted average is calculated using the coordinates of each pixel in the pixel region and its corresponding weight to obtain the corresponding true coordinates C. The weight of each pixel is determined based on its grayscale value. Compared to selecting the brightest pixel as the true coordinates C, the weighted average calculation comprehensively considers the grayscale value (brightness state) of each pixel in the pixel region, thus selecting a more accurate true coordinate C.
[0052] Referring to Figure 3, step S3 involves determining whether a preset convergence condition has been met based on the actual coordinates and theoretical coordinates of each sub-region. If the result is yes, the calibrated photopolymerization 3D printing device is obtained; otherwise, step S4 is executed. Preferably, the preset convergence condition is that for each sub-region, the deviation between at least one actual coordinate and the corresponding theoretical coordinate is within a preset deviation range. Step S4 involves performing a polynomial regression analysis on all the corresponding actual coordinates and theoretical coordinates for each sub-region to obtain the vibration scaling factor of the sub-pixel spot in the sub-region. Referring to Figure 7 below, the specific sub-steps for obtaining the vibration scaling factor D of the sub-pixel spot in sub-region A through step S4 are explained.
[0053] Step S41 involves data cleaning to remove abnormal true coordinates from all true coordinates. For example, the deviation values between each true coordinate and the theoretical coordinate are calculated, and the deviation values are sorted from smallest to largest. The true coordinates corresponding to the deviation values in the bottom 5% that are greater than twice the average of the top 95% of the deviation values are taken as abnormal true coordinates, in order to remove the influence of dust, lens defects, and other abnormalities on the data.
[0054] Step S42 involves determining at least one fitting coordinate based on all the true coordinates corresponding to sub-region A. Step S43 involves fitting the at least one fitting coordinate to the theoretical coordinates of sub-region A using polynomial regression analysis, and using the coefficients of the fitted polynomial as the vibration scaling factor. Preferably, when the polynomial regression analysis is a 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 to avoid overfitting. Preferably, when the polynomial regression analysis is a 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:
[0055] 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. Referring again to Figure 3, step S5 involves adjusting the corresponding position coordinate data according to the vibration scaling factor for each sub-region, and then continuing with step S1. It should be noted that when the deviation between the true coordinates of the subpixel spot and the theoretical coordinates of a sub-region is within a preset deviation range, if the deviation of at least one other sub-region is still outside the preset deviation range, then the position coordinate data of all sub-regions are adjusted according to the corresponding vibration scaling factor.
[0056] To better understand the technical solutions described in the above embodiments of this application, the detailed steps of calibrating a photopolymer 3D printing device 100 using a subpixel micro-scanning vibration stitching calibration method 200 are systematically explained below. First, a checkerboard pattern is projected, and images are acquired using a CCD camera. Second, an image processing algorithm is used to perform feature recognition on the image, recording the actual position of each scanning point (i.e., the true coordinates of the subpixel spot). Next, the actual position and the theoretical position (i.e., the theoretical coordinates of the sub-region) are compared, and regression analysis is performed using a binary linear polynomial to calculate the vibration scaling factor. Subsequently, the vibration position (i.e., the position coordinate data) is adjusted according to the calculation results, and the above steps are repeated for iterative correction. Finally, when the coefficient of the linear term reaches a preset convergence threshold, the calibration process is completed, and the calibrated photopolymer 3D printing device 100 is obtained. For example, referring to Figures 8 and 9, Figure 8 is a schematic diagram showing the fitted coordinates and theoretical coordinates when multiple images are acquired for each sub-region within a physical pixel region before correction of the photopolymer 3D printing device 100. Figure 9 is a schematic diagram showing the fitted coordinates and theoretical coordinates of the photopolymerization 3D printing equipment 100 after iterative correction using the sub-pixel micro-scanning vibration stitching calibration method 200 when acquiring multiple images of each sub-region within a physical pixel region. It should be noted that Figures 8 and 9 are schematic diagrams of adjusting the position coordinate data of each sub-region within a physical pixel region. The parameter M corresponding to this sub-region is 8, meaning the physical pixel region has 8*8=64 sub-regions, and the parameter N corresponding to the sub-pixel spot within this physical pixel region is 8. In Figures 8 and 9, each rectangular box represents the fitted coordinates corresponding to each sub-region, which is the average of all corresponding true coordinates. Each crosshair represents the theoretical coordinates corresponding to each sub-region. In Figure 9, the rectangular boxes largely coincide with the crosshairs, indicating that the sub-pixel micro-scanning vibration stitching calibration method 200 can achieve accurate correction of the sub-pixel spot movement controlled by the vibration mechanism 11.
[0057] It should be noted that, since the physical pixel region has a fixed size and arrangement, and each sub-pixel spot generated by the sub-pixel micro-scanning technology has the same initial relative position with the corresponding physical pixel region, the sub-pixel micro-scanning vibration stitching calibration method 200 can calibrate the entire photopolymerization 3D printing equipment 100 by adjusting the position coordinate data of each position corresponding to a sub-pixel spot, that is, there is no need to adjust the position coordinate data of each sub-pixel spot separately. Furthermore, when M is less than N, the vibration mechanism 11 controls a sub-pixel spot with a size of 1 / N to move within M*M sub-regions of the physical pixel region (the size of each sub-region is 1 / M of the size of the physical pixel region), correcting the position coordinate data corresponding to the M*M sub-regions. After obtaining the calibrated photopolymer 3D printing equipment 100, the photopolymer 3D printing equipment 100 calculates the position coordinate data corresponding to N*N sub-regions of the physical pixel region (the size of each sub-region is 1 / N of the size of the physical pixel region) based on the corrected position coordinate data corresponding to the M*M sub-regions, so as to complete the accurate calibration of the photopolymer 3D printing equipment 100 through fewer sub-regions and reduce the amount of calculation in the calibration process. For example, a curve is fitted based on the theoretical coordinates and iteratively corrected position coordinate data of M sub-regions (the size of which is 1 / M of the size of the physical pixel region) in the same row or column. Then, corresponding values are selected from the curve as position coordinate data based on the theoretical coordinates of N sub-regions (the size of which is 1 / N of the size of the physical pixel region). The vibration mechanism 11 controls the sub-pixel spot to move to the specified sub-region (the size of which is 1 / N of the size of the physical pixel region) according to the selected position coordinate data.
[0058] Another aspect of this application also includes a computer-readable medium storing computer program code that, when executed by a processor, implements the aforementioned subpixel micro-scanning vibration stitching calibration method.
[0059] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.
[0060] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.
[0061] 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 aforementioned hardware or software may be referred to as a "data block," "module," "engine," "unit," "component," or "system." The processor may 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. Furthermore, aspects of this application may manifest as computer products residing in one or more computer-readable media, including computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes, etc.), optical discs (e.g., compressed CDs, digital multifunction DVDs, etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.).
[0062] A computer-readable medium may contain a propagated data signal containing computer program code, for example, on baseband or as part of a carrier wave. This propagated signal may take various forms, including electromagnetic, optical, and so on, or suitable combinations thereof. A computer-readable medium can be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, apparatus, or device to enable communication, propagation, or transmission of a program for use. The program code located on the computer-readable medium can be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or similar media, or any combination of the above media.
[0063] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.
[0064] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values are set as precisely as feasible.
[0065] Although this application has been described with reference to specific embodiments, those skilled 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, any changes or modifications to the above embodiments within the essential spirit of this application 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, An application is made in a photopolymerization 3D printing device, the photopolymerization 3D printing device being adapted to generate sub-pixel light spots and to solidify photosensitive objects within corresponding physical pixel regions using the sub-pixel light spots. The photopolymerization 3D printing device includes a vibration mechanism, the vibration mechanism being used to control the movement of the sub-pixel light spot corresponding to the physical pixel region to the sub-region based on the position coordinate data of the sub-region within the physical pixel region. The method includes: Step S1: Acquire multiple images of the sub-pixel spot moving to multiple different sub-regions; Step S2: For each of the sub-regions, determine the true coordinates of the sub-pixel spot in the corresponding image; Step S3: Based on the actual coordinates and theoretical coordinates of each sub-region, determine whether the preset convergence condition has been met. If the determination result is yes, the calibrated photopolymerization 3D printing device is obtained; otherwise, continue to step S4. Step S4: For each of the sub-regions, perform a polynomial regression analysis on all the corresponding real coordinates and theoretical coordinates to obtain the vibration scaling factor of the sub-pixel 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 stitching as described in claim 1, characterized in that, The ratio of the size of the subpixel 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 stitching as described in claim 2, characterized in that, It also includes constructing a coordinate system based on the center of the physical pixel region when the center distance between two adjacent physical pixel regions is a fixed value, dividing the center distance into K equal parts and using each part as the smallest unit scale of the coordinate system, and obtaining the coordinates of the center of the sub-region in the coordinate system based on the relative position of the sub-region in the physical pixel region as the theoretical coordinates, where K is an integer multiple of M.
4. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 3, characterized in that, The theoretical coordinates of the sub-region are used as the initial position coordinate data corresponding to the sub-region.
5. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 1, characterized in that, It also includes acquiring the image using a CCD camera in step S1.
6. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 1, characterized in that, In step S2, the true coordinates C of the sub-pixel spot in image B corresponding to sub-region A are determined through the following steps: Extract the pixel region corresponding to the sub-pixel spot from image B; The true coordinates C are determined based on the pixel region.
7. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 6, characterized in that, Before extracting the pixel region corresponding to the sub-pixel spot from the image B, the method further includes: performing image noise reduction on the image B.
8. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 6, characterized in that, The step of determining the true coordinates C based on the pixel region includes: calculating a weighted average of the coordinates of each pixel in the pixel region and its corresponding weight to obtain the corresponding true coordinates C, wherein the weight corresponding to the pixel is obtained based on the grayscale of the pixel.
9. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 1, characterized in that, The preset convergence condition is that for each of the sub-regions, the deviation between at least one of the actual coordinates and the corresponding theoretical coordinates is within a preset deviation range.
10. The calibration method for sub-pixel micro-scanning vibration stitching as described in any one of claims 1-9, characterized in that, In step S4, the vibration scaling factor D corresponding to the sub-pixel 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 the sub-region A; The at least one fitted coordinate is fitted to the theoretical coordinates of the sub-region A by polynomial regression analysis, and the coefficients of the fitted polynomial are used as the vibration scaling factor.
11. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 10, characterized in that, 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 coordinates; The vibration scaling factor includes the first component x' in the x direction and the first component y' in the y direction, and its calculation expression is as follows: 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 stitching as described in claim 10, characterized in that, 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 fitting coordinates.
13. The calibration method for sub-pixel micro-scanning vibration stitching as described in claim 10, characterized in that, Before determining at least one fitting coordinate based on all the true coordinates corresponding to the sub-region A, the method further includes: removing abnormal true coordinates from all the true coordinates through data cleaning.
14. A photopolymerization 3D printing device, characterized in that, Suitable for generating sub-pixel light spots and solidifying the photosensitive object within the corresponding physical pixel area with the sub-pixel light spots, including: A vibration mechanism is configured to control the sub-pixel spot corresponding to the physical pixel region to move to the sub-region based on the position coordinate data of the sub-region within the physical pixel region; and host computer, The host computer includes a memory and a processor. The memory is used to store instructions that can be executed by the processor. The processor is used to execute the instructions to implement the calibration method for subpixel microscanning vibration stitching as described in any one of claims 1-13.
15. A computer-readable medium storing computer program code, which, when executed by a processor, implements the calibration method for subpixel microscanning vibration stitching as described in any one of claims 1-13.