A three-dimensional model forming method based on ee hm

Abstract

The application provides a three-dimensional model forming method based on EEHM. In view of the joint problem caused by optical distortion due to pixel overlap at the splicing position of combined projection, an edge energy equalization scheme is proposed: a slice mask image of a three-dimensional model is obtained by slicing the three-dimensional model; the slice mask image is divided and pixel filled according to the splicing mode of the projection equipment to obtain a unit division mask image of each projection equipment; a group of symmetrical gray virtual mask images are generated in a nonlinear attenuation manner; the gray virtual mask images are fused with the unit division mask images according to the projection sequence, and are projected onto the surface of liquid resin to complete the solidification of a single layer slice, and the solidification layers are stacked layer by layer to generate the entity of the three-dimensional model. The optical distortion in DLP splicing projection is solved, the printing defects of the model entity at the splicing position due to uneven ultraviolet exposure energy are improved, the surface of the model product is more flat, and the forming quality is better.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing, and particularly relates to a three-dimensional model forming method based on EEHM. BACKGROUND

[0002] At present, in the 3D printing technology, the printing plane of the CLIP type 3D printer based on mask projection is often expanded by tiling multiple projection devices, and large-size three-dimensional model entities can be manufactured with small mechanical errors and fast forming speed. However, when the projection surface is expanded by combination and splicing, optical distortion caused by overlapping pixel brightness superposition is prone to occur at the splicing position, resulting in obvious joints of the model entity at the position. SUMMARY

[0003] Therefore, the present application aims to provide a three-dimensional model forming method based on EEHM, which can solve the above problems. In this chapter, a three-dimensional model forming method based on EEHM is provided to solve the joint problem caused by optical distortion. By optimizing the optical distortion of the projection surface, the surface quality and mechanical strength of the model product can be effectively improved.

[0004] To achieve the above purpose, the present application provides a three-dimensional model forming method based on EEHM, which comprises the following steps:

[0005] slicing the three-dimensional model to obtain a slice mask image of the three-dimensional model;

[0006] According to the projection device splicing mode, the slice mask image is divided and pixel-filled to obtain a unit division mask image of each projection device;

[0007] a set of symmetrical gray virtual mask images are generated in a non-linear attenuation manner;

[0008] The gray virtual mask images are fused with the unit division mask images according to the projection order, and are projected onto the surface of the liquid resin to complete the solidification of a single layer of slice, and the layers are stacked to generate a three-dimensional model entity.

[0009] Further, the step of slicing the three-dimensional model to obtain a slice mask image of the three-dimensional model comprises the following steps:

[0010] According to a preset thickness, the three-dimensional model is uniformly sliced from the bottom to the top with a cross section perpendicular to the Z axis to obtain a series of original slice mask images of the three-dimensional model.

[0011] Further, the step of pixel-filling to obtain a unit division mask image of each projection device comprises the following steps:

[0012] In the left and right splicing of two DLP projection devices, the pixel width of the overlapping area is γ, the left split mask image is placed at the rightmost side of the left DLP projection device, if the entire DLP projection surface cannot be filled, black pixels are filled in the insufficient part to obtain the left unit mask image;

[0013] The right split mask image fills the γ-width pixel image at the rightmost side of the left split mask image at the leftmost side of the right split mask image before filling the insufficient part of the image, then the left split mask image is placed at the leftmost side of the right DLP projection device, and black pixels are filled in the insufficient part on the right side to generate the right unit mask image.

[0014] Further, the merging of the gray virtual mask according to the projection sequence and the unit split mask image comprises:

[0015] The left and right gray virtual mask images included in a group of symmetric gray virtual mask images are respectively merged with the left and right unit mask images to obtain an ordered set of left and right unit mask images for optical correction of the overlapping area, and the merging is multiplying the brightness value of the pixel point in the overlapping area of the unit mask image by the attenuation coefficient of the corresponding position of the nonlinear attenuation curve designed by the EEHM algorithm to modify the brightness value of the target pixel point.

[0016] Further, the projection to the surface of the liquid resin to complete the solidification of a single layer of slices, and the layer-by-layer stacking of the solidified layers to generate a three-dimensional model entity, comprises:

[0017] The ordered set of left and right unit mask images for optical correction of the overlapping area is taken as a 3D printing data source, which is transmitted to the corresponding DLP device by the printing control software of the upper computer, and is projected to the photosensitive resin surface after splicing to obtain a solid thin layer, which is stacked layer by layer to form a three-dimensional entity.

[0018] Further, the generation of a group of symmetric gray virtual mask images in a nonlinear attenuation manner comprises:

[0019] An exponential decay function and a triangular decay function are combined to construct a generation curve of the gray virtual mask image, and the formula is as follows:

[0020]

[0021]

[0022] wherein B L (d li ) represents the left curve, B R (d ri ) represents the right curve, α and p are constants for optimizing the exponential decay function, λ and β are constants for optimizing the triangular decay function, D is the pixel width of the overlapping area of adjacent projection devices, and d liand d ri For the pixel point X i The left and right distances between the pixel point and the edge of the non-overlapping area, m and n are the specific gravity parameters.

[0023] Further, the determination process of the parameters in the formula is as follows: first, adjust the parameters a and p of the exponential decay function until the brightness of the middle pixels in the overlapping area changes uniformly, and record the parameter information; then adjust the parameters l and b of the triangular decay function to eliminate the brightness step effect caused by the too fast brightness change of the edge pixels; finally, substitute the optimal parameters a and p, l and b into the formula, and adjust the weights of the exponential decay function and the triangular decay function through the specific gravity parameters m and n to determine the final generation curve.

[0024] Further, the parameter values of the formula are as follows: a = 0.9, p = 0.75, l = 1.25, b = 0.75, m = 1.1, and n = 0.83.

[0025] In general, the advantages of the present application and the experience brought to the user are that the edge energy uniformization scheme of the present application can solve the optical distortion in DLP splicing projection in a simple and efficient way, improve the printing defects of the model entity caused by uneven ultraviolet exposure at the splicing place, make the surface of the model product more flat, improve the molding quality, improve the mechanical strength of the model entity, and achieve the goal of fully exerting the advantages of CLIP in high speed, high precision and high performance, while improving the overall quality of the model, providing a good experimental platform for further exploring the large-format three-dimensional model continuous scheme based on CLIP. BRIEF DESCRIPTION OF DRAWINGS

[0026] In the drawings, like reference numerals refer to like elements throughout the various drawings. The drawings are not necessarily to scale, the emphasis instead being placed upon illustrating principles of the application. It should be understood that the drawings are merely depictions of some embodiments of the application and should not be construed as limiting the scope of the application.

[0027] Figure 1 A schematic diagram of a nonlinear symmetric decay function is shown.

[0028] Figure 2 A schematic diagram of the distance between the pixel point and the edge of the overlapping area is shown.

[0029] Figure 3 A schematic diagram of the adjustment of the parameters of the exponential decay function is shown.

[0030] Figure 4 A schematic diagram of the adjustment of the parameters of the triangular decay function is shown.

[0031] Figure 5 A schematic diagram of the nonlinear decay function of EEHM is shown.

[0032] Figure 6 An energy output result schematic diagram showing that EEHM is not used.

[0033] Figure 7 An energy output result schematic diagram showing that EEHM is used.

[0034] Figure 8 A forming process schematic diagram of EEHM according to an embodiment of the application is shown.

[0035] Figure 9 A surface quality evaluation schematic diagram is shown.

[0036] Figure 10 A tensile test process schematic diagram is shown.

[0037] Figure 11 A wolf head forming quality comparison diagram is shown.

[0038] Figure 12 A structure schematic diagram of an electronic device provided by an embodiment of the application is shown.

[0039] Figure 13 A schematic diagram of a storage medium provided by an embodiment of the application is shown. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings.

[0041] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0042] The present application proposes an edge energy homogenization scheme (Edge Energy Homogenization Method, EEHM). The design idea of the EEHM forming scheme is to design a set of symmetrical attenuation grayscale virtual masks in a nonlinear attenuation manner based on experimental data, fuse the grayscale virtual masks with the adjacent DLP split mask images, realize uniformization and fusion processing of the overlapping area ultraviolet light, and ensure the uniformity of the overall projection surface brightness.

[0043] 1. Nonlinear attenuation function design

[0044] The core of the EEHM algorithm is to select the generation curve of the grayscale mask image. In two-dimensional coordinates, the attenuation curves of the left and right overlapping areas are as follows Figure 1As shown, the X-axis is the normalized horizontal coordinate of the pixel overlap area width, the edge of the projection device is the starting point of the pixel intensity decay, and the inner edge of the overlap area is the end point of the pixel intensity decay. The Y-axis is the decay coefficient of the pixel intensity, 0 represents complete decay, and 1 represents no decay. Multiplying the intensity value of the target position pixel by the gray virtual mask gray value at the corresponding position can obtain the gray value. In the EEHM scheme, the left projection device selects a decay curve from left to right from 1 to 0, and the right projection device selects a decay curve from right to left from 1 to 0. The decay curve is converted into a gray virtual mask image, which is fused with the segmented cross-sectional mask image, respectively. Due to the symmetry of the left and right gray decay, the decay coefficients at the same position in the overlap area are always 1, and under the theoretical condition, the ultraviolet light intensity in the entire overlap area is consistent with that in the non-overlap area.

[0045] After analyzing the advantages and disadvantages of the existing nonlinear decay function in actual projection, the EEHM algorithm uses a combination of exponential decay function and triangular decay function to construct the generation curve of the gray virtual mask. This scheme not only retains the advantage of uniform brightness change in the overlap area of the exponential decay function, but also fully utilizes the edge smoothing characteristics of the triangular decay function to improve the unnatural transition defect between the overlap area and the non-overlap area, ensuring the uniformity of the ultraviolet light intensity on the projection surface. The traditional exponential decay function and the triangular decay function are shown in formulas (1) and (2).

[0046]

[0047] wherein α and p are constants, and t is the normalized horizontal coordinate of the pixel width of the overlap area, with the innermost side of the projection picture being 1 and the outermost side being 0.

[0048]

[0049] wherein α is a constant, and θ is the pixel width of the overlap area mapped to the [0, 2π] horizontal coordinate, with the innermost side of the projection picture being 2π and the outermost side being 0.

[0050] Due to the brightness offset of the optical device, there may be a certain brightness decay at the edge of the device during ultraviolet light projection, and the total brightness at the junction of the overlap area and the non-overlap area is not necessarily 1. In order to more accurately correct the light intensity at the edge, the EEHM algorithm optimizes the traditional triangular decay function to obtain the improved triangular decay function (3). The improved triangular decay function takes the mathematical property of cos 2 θ+sin 2 θ=1 as the basic point decay, uses a variable parameter α instead of the original square coefficient, and adds an uncertain coefficient β to the variable x, making it more flexible. In the subsequent EEHM algorithm design and implementation process, the best projection effect is obtained by adjusting the parameters α and β.

[0051]

[0052] wherein, α and β are constants, and x is the normalized horizontal coordinate of the pixel overlap region width.

[0053] Although the exponential decay function in the EEHM algorithm makes the image brightness in the overlap region change uniformly, the improved triangular function improves the problem of large brightness difference in the image edge, but for narrow optical seams, the brightness decay from 1 is still not smooth enough. Therefore, when designing the nonlinear decay function in the EEHM algorithm, variable parameters m and n are introduced to combine the exponential decay function and the improved triangular decay function, the purpose is to dynamically adjust the proportion of the two according to the distance of the decay point from the edge to obtain better projection effect, as shown in Figure 2 MNPQ is the overlap region, D is the pixel overlap region width, d li and d ri is the distance between the pixel point X i and the edge of the non-overlapping region, and the ratio of the distance to the width of the overlapping pixel is set as an independent variable.

[0054] The nonlinear decay function of the EEHM algorithm is designed as formula (4). Wherein, α and p are constants for optimizing the exponential decay function, λ and β are constants for optimizing the triangular decay function, and D is the pixel width of the adjacent projection device overlap. L (d li ) represents the left curve, and B R (d ri ) represents the right curve.

[0055]

[0056] When the decay point is far from the edge of the projection device, the triangular decay function occupies a larger proportion; when the decay point is close to the junction of the overlap region and the non-overlapping region, the proportion of the exponential function is larger, which can fully play the advantages of the exponential decay function and the triangular decay function, and make the entire projection surface display the three-dimensional model section mask image after splicing without brightness difference.

[0057] 2 Distortion elimination algorithm implementation

[0058] This section further describes the implementation process of EEHM algorithm. The main work is to determine the values of the parameters in the nonlinear attenuation function of EEHM algorithm through experimental data and actual projection effect, mainly including the following three stages: first, adjust the parameters a and p of the exponential attenuation function until the brightness of the middle pixels in the overlapping area changes uniformly, and record the parameter information; then adjust the parameters λ and β of the triangular attenuation function to eliminate the brightness step effect caused by the rapid change of the brightness of the edge pixels; finally, put the optimal parameters recorded in the nonlinear attenuation function of EEHM algorithm, and adjust the weights of the two through the specific gravity parameters m and n to determine the final generation curve.

[0059] The main role of exponential attenuation is to ensure that the brightness of the pixels in the overlapping area changes uniformly, so when selecting parameters for the exponential attenuation function, the middle section of the exponential attenuation curve should be as smooth as possible. In formula (4), a and p are both parameters to be adjusted for the exponential attenuation function, Figure 3 (a) is to set a as a constant value, and select different values of p. In actual projection, the smaller the value of p, the higher the brightness of the overlapping area, the smoother the middle section of the attenuation curve, and the brightness of the overlapping area changes uniformly; the larger the value of p, the lower the brightness of the overlapping area, and when the change range of the middle section of the attenuation curve is large, a "dark band" appears in the center of the overlapping area. Figure 3 (b) sets p as a constant value. The smaller the value of a, the lower the brightness of the overlapping area, the faster the change of the middle section of the curve, but the transition of the edge is relatively smooth, and the edge brightness step effect is not obvious; the larger the value of a, the higher the brightness of the overlapping area, and the change of the middle section of the curve is relatively slow, and the brightness is relatively uniform. Through experimental comparison of the projection effect under different parameters and verification using an optical meter, it is obtained that when a = 0.9 and p = 0.75, the overlapping area obtains a relatively good effect of uniform light intensity change.

[0060] At this time, after adjusting the optical joint by exponential attenuation, the phenomenon of uneven change of pixel brightness in the overlapping area has been obviously improved, but from Figure 3 It can be seen that the change of the two ends of the exponential attenuation curve is very sharp, and the brightness of the edge of the image in the projection plane changes obviously, showing a brightness gradient effect. When the section mask image is light-cured, the brightness mutation will cause a slight protrusion or depression of the solid thin layer at that place, and the inconsistent curing thickness will cause the section thin layer to stretch at that place, and the model entity is prone to breakage due to stress concentration. The triangular attenuation function used by EEHM algorithm effectively improves this problem. The improved triangular function has two parameter variables λ and β. When β is set as a fixed value and λ is set as different values, the attenuation curve is as follows Figure 4(a) shows that the smaller the value of λ, the greater the brightness of the overlapping area, but the sharp curve in the middle will cause the "dark band" in the overlapping area; the larger the value of λ, the lower the brightness of the overlapping area, the brightness changes more evenly, and the edge transition is relatively flat, and there is no obvious brightness gradient change. When λ is set to a constant value, the attenuation function curve of β taking different values is shown in (b) shows that the smaller the value of β, the greater the brightness of the overlapping area, and the curve changes sharply at first, and a "dark band" will appear at the boundary; the larger the value of β, the smaller the brightness of the overlapping area, and the edge transition is relatively flat. Through experimental comparison of the projection effect under different parameters and verification using an optical meter, it is found that when λ = 1.25 and β = 0.75, the triangular attenuation function achieves the best effect in improving the brightness difference of the edge.

[0061] The last step of the EEHM algorithm design is to adjust the parameters to the optimal exponential attenuation function and triangular attenuation function applied to the nonlinear attenuation function designed by EEHM. In order to maximize the advantages of the uniform brightness change of the exponential attenuation function and the flat edge transition of the triangular attenuation function, variable parameters m and n are introduced into the function design, and the proportion of the two is dynamically adjusted according to the position of the attenuation point. Through repeated experiments and measurement using an optical meter, it is found that when m = 1.1 and n = 0.83, the grayscale virtual mask generated by the nonlinear attenuation curve under this parameter can make the three-dimensional section mask image after fusion with the split mask image have no optical seam when projected on the photosensitive resin surface. The grayscale virtual mask generation curve under the EEHM scheme is shown in (b). Figure 5

[0062] From the above experimental process, it can be seen that the exponential attenuation function and the triangular attenuation function have obvious advantages in optical adjustment of the overlapping area, but the disadvantages cannot be ignored. If the exponential attenuation function or the triangular attenuation function is used alone to correct the overlapping area, the optical seam problem cannot be completely eliminated. The EEHM algorithm proposed in this application combines the exponential attenuation function and the triangular attenuation function, uses their respective advantages to compensate for the shortcomings of the other to obtain the best projection effect. As shown in (a), without using the EEHM scheme, the ultraviolet exposure energy of the pixel overlapping area of the projection surface can almost double, and the energy output of the projection surface is very uneven. After using the EEHM scheme to design the grayscale virtual mask to correct the brightness of the overlapping area, the ultraviolet energy output of the projection surface is measured by an optical meter, as shown in (b), and the light intensity distribution of the projection surface is uniform. Figure 7

[0063] 3 Distortion elimination and splicing forming process

[0064] The three-dimensional model forming process based on the EEHM scheme mainly consists of model preprocessing, edge energy equalization processing and printing control, as shown in (a). Figure 8 The three-dimensional model forming process based on the EEHM scheme mainly consists of model preprocessing, edge energy equalization processing and printing control, as shown in (a).​​​Figure 8 The left and right unit mask images are obtained by the above steps.

[0065] Step 1: Uniform slicing of the three-dimensional model. The three-dimensional model is uniformly sliced from the bottom up with a cross section perpendicular to the Z axis according to the specified thickness, obtaining a series of original slice mask images of the three-dimensional model.

[0066] Step 2: Fixed segmentation of the slice mask image. The slice mask image is segmented into several sub-segmentation mask images according to the fixed integration of the splicing mode of the DLP projection device, and each sub-segmentation mask image corresponds to a DLP projection device.

[0067] Step 3: Pixel filling of the sub-segmentation mask image to generate a unit mask image. Taking the left and right splicing of the two DLP projection devices in the application as an example, the pixel width of the overlapping area is γ. To ensure that the sub-segmentation mask image is aligned at the edge and does not deform when projected, the left segmentation mask image is placed at the rightmost side of the left DLP projection device. If the entire DLP projection surface cannot be filled, black pixels are filled in the insufficient part to obtain the left unit mask image. The right segmentation mask image needs to be filled with γ width pixel image at the leftmost side of the right segmentation mask image before filling the insufficient part, and then placed at the leftmost side of the right DLP projection device to fill the insufficient part on the right with black pixels to generate the right unit mask image.

[0068] Step 4: Edge energy homogenization processing. The left and right gray virtual mask images designed by the EEHM algorithm are respectively fused with the left and right unit mask images. The so-called fusion is to multiply the brightness value of the pixel point in the overlapping area of the unit mask image by the attenuation coefficient at the corresponding position of the attenuation curve designed by the EEHM algorithm to modify the brightness value of the target pixel point.

[0069] After the three-dimensional model is processed by the above steps, the ordered set L[0, N] and R[0, N] of left and right unit mask images with optical correction of the overlapping area can be obtained, (where N is the number of slice mask images after uniform segmentation of the three-dimensional model), which is used as the 3D printing data source. Finally, the printing control software of the upper computer transmits it to the corresponding DLP device, and the continuous projection to the photosensitive resin surface after splicing obtains a solid thin layer, which is stacked layer by layer to form a three-dimensional entity.

[0070] According to the above process, the EEHM forming scheme reads the slice mask images in the three-dimensional model slice file according to the model stacking order, then segments each layer image according to the splicing mode of the DLP projection device, and fuses the segmented sub-segmentation mask with the gray virtual mask designed by the EEMH algorithm. Through DLP projection to the liquid resin surface, the solidification of a single layer slice is completed, and the above process is repeated to complete the printing work. The time complexity of printing all layers is O(N), and the pseudo code of the edge energy homogenization fixed splicing forming method is as follows.

[0071]

[0072]

[0073] 4 Experimental results and analysis

[0074] The printing effect of the EEHM scheme is evaluated on the two DLP projection fixed splicing CLIP type 3D printer experimental platforms designed in the application, including model surface treatment effect evaluation, model mechanical strength evaluation and overall forming quality evaluation of the model under the EEHM scheme.

[0075] 4.1 Joint treatment effect evaluation

[0076] The joint treatment effect evaluation is composed of model upper surface evaluation and model side surface evaluation. A cuboid with a length of 60mm, a width of 30mm and a height of 2.5mm is selected as a three-dimensional model, a high-toughness resin with good surface finish and high fluidity is used as the printing material, the ultraviolet light intensity is set to be greater than 250μm in transmission depth, the actual exposure energy is 8.52mW / cm 2 , and three schemes of direct exposure forming (denoted as scheme A), half-decay forming (denoted as scheme B) and EEHM forming (denoted as scheme C) are used to print the model products respectively.

[0077] The model products are as shown in Figure 9 , the upper surface solidification thickness of the overlapping area on the upper surface of the cuboid part printed by the scheme A without optical correction is obviously higher than that of other areas, the cuboid printed part has obvious distortion in the overlapping area, and the side surface has obvious vertical joint seams in the overlapping area, and the model entity surface is relatively rough. Due to the brightness deviation of the projection equipment, the model product printed by the scheme B has a slight depression in the upper surface overlapping area, and the side surface joint presents two not obvious vertical joint seams, and the model forming quality is still not ideal. The overall solidification thickness of the model product printed by the scheme C is basically consistent, the upper surface is smooth as a whole, and the side surface joint trace is obviously reduced, compared with the previous two forming schemes, the quality of the cuboid printed part is obviously improved.

[0078] 4.2 Mechanical strength evaluation

[0079] In terms of mechanical properties, a tensile test experiment as shown in Figure 10 is designed, the test object is a circular ring model with an outer diameter of 50mm, an inner diameter of 40mm and a height of 0.5mm, and the tensile failure test is performed by using the direct exposure forming scheme (denoted as A), the half-decay forming scheme (denoted as B) and the EEHM forming scheme (denoted as C) respectively, 10 test pieces are printed for each forming scheme, and the average value of the breaking tension of each group of test pieces is recorded in table 1.

[0080] The average breaking force under the direct exposure forming scheme is 287.7N, the average breaking tension under the half-decay forming scheme is 324.4N, and the average breaking tension of the test piece under the EEHM scheme is 380.3N. Compared with the first two forming schemes, the breaking tension of the test piece under the EEHM scheme is obviously higher than that of the first two schemes, which indicates that the printed piece under the EEHM scheme has higher mechanical strength.

[0081] Table 1: Ring printed piece tension test results

[0082]

[0083] 4.3 Size accuracy evaluation

[0084] A wolf head three-dimensional model with length, width and height dimensions of (88.37mm, 76.49mm, 13.50mm) is selected, and a test piece is printed by using direct exposure forming (denoted as A), half-decay forming (denoted as B), exponential decay forming scheme (denoted as C), triangular decay forming scheme (denoted as D), and EEHM forming scheme (denoted as E), respectively, and the printing results are as shown in Figure 11 The local enlarged A scheme model entity can clearly see a crack from the wolf's nose to the top of the head, and the model is easy to break along the joint; the forming quality of the B scheme is improved compared with the A scheme, but there is still a joint mark in the middle of the printed piece that penetrates the whole wolf head; the C scheme and the D scheme are local improvements of the EEHM scheme, and only the C scheme using exponential decay has a slight protrusion at the edge of the joint, and the middle section of the joint is smooth as a whole; the D scheme has no obvious joint mark at the edge of the joint, but a slight depression appears in the middle section; and the EEHM scheme using exponential decay and triangular function decay in combination has a smoother surface and higher forming precision.

[0085] The results of multiple model printing experiments show that the edge energy equalization scheme can solve the optical distortion in DLP splicing projection in a simple and efficient way, improve the printing defects of the model entity at the splicing place due to uneven ultraviolet exposure energy, make the surface of the model product smoother, and improve the forming quality and mechanical strength of the model entity, so as to achieve the goal of fully exerting the advantages of CLIP in high speed, high precision and high performance, and improving the overall quality of the model, and provide a good experimental platform for further exploring the continuous scheme of large-format three-dimensional model based on CLIP.

[0086] The application also provides an electronic device corresponding to the EEHM-based three-dimensional model forming method provided in the foregoing embodiments, to execute the EEHM-based three-dimensional model forming method. The embodiments of the application are not limited.

[0087] Please refer to Figure 12This illustrates a schematic diagram of an electronic device provided by some embodiments of this application. For example... Figure 12 As shown, the electronic device 20 includes: a processor 200, a memory 201, a bus 202, and a communication interface 203. The processor 200, the communication interface 203, and the memory 201 are connected via the bus 202. The memory 201 stores a computer program that can run on the processor 200. When the processor 200 runs the computer program, it executes the EEHM-based three-dimensional model forming method provided in any of the foregoing embodiments of this application.

[0088] The memory 201 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 203 (which can be wired or wireless), such as the Internet, wide area network, local area network, or metropolitan area network.

[0089] Bus 202 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. Memory 201 is used to store programs. After receiving an execution instruction, processor 200 executes the program. The EEHM-based 3D model forming method disclosed in any of the foregoing embodiments of this application can be applied to processor 200, or implemented by processor 200.

[0090] The processor 200 can be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above method can be completed by the integrated logic circuit of hardware in the processor 200 or the instruction in the form of software. The processor 200 described above can be a general processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a ready programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. Each method, step and logic block diagram disclosed in the embodiments of the present application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read only memory, a programmable read only memory or an electrically erasable programmable memory, a register, etc. The storage medium in the art. The storage medium is located in the memory 201, and the processor 200 reads the information in the memory 201, and combines the hardware to complete the steps of the above method.

[0091] The electronic device provided by the embodiments of the present application and the EEHM-based three-dimensional model forming method provided by the embodiments of the present application have the same beneficial effects as the method adopted, run or implemented.

[0092] The present application also provides a computer readable storage medium corresponding to the EEHM-based three-dimensional model forming method provided by the preceding embodiments. Please refer to Figure 13 The computer readable storage medium shown is an optical disc 30, and a computer program (i.e. program product) is stored on the optical disc 30. When the computer program is run by a processor, the EEHM-based three-dimensional model forming method provided by any of the preceding embodiments is executed.

[0093] It should be noted that examples of the computer readable storage medium can also include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other optical, magnetic storage medium, which will not be described one by one here.

[0094] The computer readable storage medium provided by the above embodiments of the present application has the same inventive concept as the three-dimensional model forming method based on EEHM provided by the embodiments of the present application, and has the same beneficial effects as the method adopted, run or implemented by the application stored therein.

[0095] It should be noted that:

[0096] The algorithms and displays presented herein are not inherently related to any particular computer, virtual system, or other apparatus. Various general purpose systems can be used with these teachings, with or without accompanying specific hardware. In

[0097] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0098] Similarly, it is to be understood that the mechanical features of the present application will at times be described in the specification by way of illustrative example in the description of the exemplary embodiments of the application. Such description, however, should not be construed to mean that the application is limited to such exemplary embodiments, and it is understood that the description of a particular feature in relation to an embodiment of the application is to be understood as potentially applicable to other embodiments of the application, unless specifically noted otherwise. Moreover, it should be understood that the description of the exemplary embodiments of the application is intended to be illustrative, and not be of a limiting nature.

[0099] Those skilled in the art will appreciate that the modules in the apparatuses in the embodiments can be adapted and placed in one or more apparatuses other than the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and furthermore can be split into multiple sub-modules or sub-units or sub-components. Any combination of all the features disclosed in the specification (including the accompanying claims, abstract and drawings), and any method or process or device of any combination of the features disclosed in the specification (including the accompanying claims, abstract and drawings) can be taken, except that at least some of such features and / or processes or units are mutually exclusive, unless explicitly stated otherwise. Each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by alternative features providing the same, equivalent, or similar functions unless stated explicitly otherwise.

[0100] Furthermore, those skilled in the art will appreciate that different embodiments of the application have different features, and thus not all embodiments of the application will exhibit all of the features described or claimed herein. It will further be appreciated that certain features can not be present in certain embodiments of the application. Thus, not all aspects of the features described or claimed herein are required in every embodiment of the application.

[0101] The various component embodiments of the present application can be implemented in hardware, or as software modules running in one or more processors, or in combinations thereof. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functionality of some or all of the components in a virtual machine creation system according to embodiments of the present application. The present application can also be implemented as a program of instructions for performing part or all of the methods described herein, e.g., a computer program and a computer program product. Such program of the present application can be stored on a computer readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier signal, or in any other form.

[0102] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a system claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. The use of relative terms such as 'about','substantially', 'approximately' and the like is intended to broadly describe the nature of the characteristics, features and / or elements, and is not intended to be limiting. The terms 'comprise(s)', 'comprising', 'contain(s)', 'containing', 'include(s)', and 'including' are used interchangeably and are meant to be construed in a non-exclusive way.

[0103] The above description is only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various changes or replacements within the technical range disclosed by the present application, and these should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for three-dimensional model forming based on EEHM, characterized by, The method comprises the following steps: obtaining a slice mask image of a three-dimensional model by slicing the three-dimensional model; dividing the slice mask image according to a projection device splicing mode, and performing pixel filling to obtain a unit division mask image of each projection device; generating a set of symmetrical gray virtual mask images in a non-linear attenuation manner; fusing the gray virtual mask images with the unit division mask images according to a projection sequence, and projecting the fusing result onto a liquid resin surface to complete single-layer slice solidification, and then stacking the solidified layers to generate a three-dimensional model entity; the pixel filling to obtain the unit division mask image of each projection device comprises the following steps: when two DLP projection devices are spliced left and right, the pixel width of the overlapping area is γ, the left division mask image is placed at the rightmost side of the left DLP projection device, if the entire DLP projection surface cannot be filled, black pixels are filled in the insufficient part to obtain a left unit mask image; the right division mask image is filled with the γ-width pixel image at the rightmost side of the left division mask image at the leftmost side of the right division mask image, then the left division mask image is placed at the leftmost side of the right DLP projection device, and black pixels are filled in the insufficient part on the right side to generate a right unit mask image; the fusing of the gray virtual mask images with the unit division mask images according to the projection sequence comprises the following steps: the left and right gray virtual mask images included in the set of symmetrical gray virtual mask images are fused with the left and right unit mask images respectively to obtain an ordered set of left and right unit mask images with optical correction of the overlapping area, and the fusing is to multiply the brightness value of a pixel point in the overlapping area of the unit mask image by the attenuation coefficient of the corresponding position of the non-linear attenuation curve designed by the EEHM algorithm to modify the brightness value of the target pixel point.

2. The method of claim 1, wherein the slice mask image of the three-dimensional model is obtained by slicing the three-dimensional model at a predetermined thickness.

3. The method of claim 1, wherein the three-dimensional model entity is generated by projecting the fusing result onto the liquid resin surface to complete single-layer slice solidification, and then stacking the solidified layers.

4. The method of claim 1, wherein the set of symmetrical gray virtual mask images is generated in a non-linear attenuation manner.

5. The method of claim 4, wherein the generation curve of the gray virtual mask image is constructed by combining an exponential attenuation function and a triangular attenuation function, and the formula is as follows: ​ ​ ​ ​ ​ wherein B L (d li ) represents a left curve, B R (d ri ) represents a right curve, a and p are constants for optimizing an exponential decay function, and l and b are constants for optimizing a triangular decay function, D is a pixel width of overlap of adjacent projection devices, d li and d ri are left and right distances between the pixel point X i and edges of non-overlapping regions, and m and n are proportionality parameters. ​ The determination process of the parameters in the formula is as follows: first, the parameters a and p of the exponential decay function are adjusted until the brightness of the intermediate pixels in the overlapping area changes uniformly, and the parameter information is recorded; then, the parameters λ and β of the triangular decay function are adjusted to eliminate the brightness step effect caused by the too fast brightness change of the edge pixels; finally, the optimal parameters a and p, λ and β are substituted into the formula, and the weights of the exponential decay function and the triangular decay function are adjusted through the specific gravity parameters m and n to determine the final generation curve.

6. The method of claim 4 or 5, wherein, The final values of the parameters of the formula are as follows: a = 0.9, p = 0.75, λ = 1.25, β = 0.75, m = 1.1, and n = 0.

83.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor runs the computer program to implement the method of any one of claims 1-5.

8. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method of any one of claims 1-5.

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