Movable DLP projection positioning system and method based on visual calibration

Abstract

The invention discloses a movable DLP projection positioning system and method based on visual calibration, and the system can achieve the high-precision projection of an overall large-size image in a splicing manner through the segmented projection and the independent precise visual calibration of each segment. Secondly, a fixed scale with a special mark is used as an absolute reference, closed-loop visual feedback calibration is carried out in combination with a camera, and high-precision projection positioning can be achieved; meanwhile, after the projector moves to a new position every time, the calibration process can be automatically completed, manual intervention is not needed, the preparation time is greatly shortened, and the working efficiency is improved; in addition, the projector can move on the guide rail and easily cover different areas of a large working table or a mold table, and the problem that the fixed projection range is limited is solved.

Description

Technical Field

[0001] The present invention relates to the field of industrial production technology, and in particular to a movable digital light processing projection positioning system and a control method for automatically calibrating and calibrating by combining visual feedback and a ruler. Background Art

[0002] In modern industrial manufacturing, it's often necessary to precisely project marking lines, contours, or work instructions onto workpieces or mold surfaces. Traditional marking methods, such as manual scribing and the use of fixed templates, suffer from inefficiencies, low precision, limited flexibility, and prone to errors.

[0003] Therefore, DLP projection technology is now widely used, which can improve efficiency and flexibility to a certain extent. However, the existing DLP projection application methods also have some limitations:

[0004] Fixed projection: For large work surfaces or mold tables, a single fixed-position projector is difficult to cover the entire area, or it may cause large projection distortion and reduced accuracy in the edge areas.

[0005] Manual alignment: After moving the projector, complex manual re-alignment and calibration is usually required, which is time-consuming and labor-intensive, and the accuracy depends on the operator's experience and responsibility.

[0006] Poor environmental adaptability: Changes in the on-site environment, such as lighting and slight displacement of the mold platform, may lead to a decrease in projection accuracy and lack of automatic compensation mechanism.

[0007] It is difficult to guarantee accuracy over a large range: As the projection distance and range increase, factors such as lens distortion and installation errors have a more significant impact on the final projection accuracy, making it difficult to ensure uniform high accuracy over a large range.

[0008] Therefore, there is an urgent need for a projection system and method that can move over a large range and quickly and automatically complete high-precision calibration and positioning after each movement to meet the requirements of modern industrial production for precision and efficiency. Summary of the Invention

[0009] In response to the technical problems of limited projection range, low calibration efficiency and low large-scale projection accuracy in existing projection methods, the purpose of the present invention is to provide a movable DLP projection positioning system based on visual calibration, which can use equipment with limited projection range to achieve high-precision splicing projection of large-size images. On this basis, a movable DLP projection positioning method based on visual calibration is also provided, which effectively overcomes the problems existing in the existing technology.

[0010] In order to achieve the above-mentioned objectives, the present invention provides a movable DLP projection positioning system based on visual calibration, comprising a projection unit and a working mold platform unit, the projection path of the projection unit being arranged relative to the working mold platform unit, and further comprising a moving unit, an image acquisition unit, a calibration unit and a control processing unit; the moving unit is movably connected to the projection unit, and the projection unit can move laterally along the moving unit; the calibration unit is installed at the edge of the working mold platform unit close to the projection unit, and has a plurality of predefined and easy-to-identify special physical marking points thereon; the image acquisition unit is arranged relative to the projection unit, and can move with the projection unit to simultaneously capture the marking points on the calibration unit and the test projection points formed by the projection unit projected onto the surface of the working mold platform unit; the control processing unit interacts with data of the projection unit and the image acquisition unit respectively.

[0011] Furthermore, the control processing unit includes a receiving module, a data processing module and a control module;

[0012] The receiving module is used to receive the specific target marking points collected by the image acquisition unit and the trial projection points formed by the projection unit projected onto the surface of the mold stage unit; the receiving module interacts with the data processing module for data, and the receiving module transmits the received specific target marking points and the trial projection points formed by projecting onto the surface of the mold stage unit to the data processing module. The data processing module first calculates the actual projection deviation of the trial projection points formed by the projection unit projected onto the surface of the mold stage unit relative to the specific target marking points, and calculates the geometric correction parameters based on the deviation; the control module interacts with the data processing module and the projection unit for data respectively, and the control module controls the projection unit according to the parameters to accurately project the corrected segmented image to a predetermined position on the mold stage unit.

[0013] To achieve the above-mentioned object, the present invention provides a method for positioning a movable DLP projection projector based on visual calibration. The method for positioning a movable DLP projection projector based on visual calibration is implemented in conjunction with the method for positioning a movable DLP projection projector based on visual calibration. The method for positioning a movable DLP projection projector based on visual calibration comprises the following steps:

[0014] S1: Planning of projection image segmentation and position coordinates;

[0015] S2: Load the camera intrinsic parameters and the precise world coordinates of all scale markers based on the planning of S1 position coordinates;

[0016] S3: Based on the target physical position determined in S1, initialize the mobile projector to the target position of the target segment;

[0017] S4: Start the segmented calibration procedure;

[0018] S5: Control the projector to test project the target segmented pattern;

[0019] S6: Capturing and processing the image of the pattern projected by S5;

[0020] S7: performing coordinate mapping and error determination on the segmented image captured by S6;

[0021] S8: solving the correction transformation for the deviation vector calculated in S7;

[0022] S9: pre-distorting the current image segment using the correction transformation solved in S8 and generating a corrected segmented image;

[0023] S10: Control the projector to project the corrected segmented image onto the working mold platform;

[0024] S11: The projector moves to the next segmented position and performs the above operations S2-S10.

[0025] Furthermore, the S1 includes the following steps:

[0026] S11: Segment the entire image according to the effective field of view of the projector, the required accuracy, and the optional overlap;

[0027] S12: determining the target physical position of the projector on the guide rail during segmented projection according to the segmented image formed in S11;

[0028] S13: Pre-mark on the ruler the reference point to which each segmented image actually corresponds when projected onto the mold platform.

[0029] Furthermore, the S6 includes the following steps:

[0030] S61: command the camera to capture an image;

[0031] S62: Identify the image coordinates of the scale mark points associated with the segmented pattern in the image;

[0032] S63: Identify the image coordinates of the test feature points projected by the projector in the image.

[0033] Furthermore, the S7 includes the following steps:

[0034] S71: Using the camera intrinsic parameters and the known world coordinates of the scale mark points, establish an image-to-world coordinate mapping at the current position;

[0035] S72: Mapping the image coordinates of the test feature point to the world coordinates to obtain its actual projected world coordinates;

[0036] S73: Calculate the deviation vector of the test feature point relative to its corresponding theoretical target world coordinates in S71.

[0037] Furthermore, in said S8, a plurality of pairs of theoretical target world coordinates and actual projected world coordinates or deviations are used to solve a correction transformation for accurately mapping the projector coordinates to the world coordinates or compensating for the deviation at the current position.

[0038] Furthermore, the S9 includes the following steps:

[0039] S91: Obtain segmented image content;

[0040] S92: Apply inverse transformation to all actual projected world coordinates on the segmented image to calculate the corresponding projector coordinates;

[0041] S93: Generate a corrected segmented image based on the projector coordinates calculated in S92.

[0042] The present invention provides a movable DLP projection positioning system and method based on visual calibration, which effectively overcomes the accuracy loss and distortion problems of single large-scale projection and can achieve high-precision projection of overall large-scale images in a splicing manner.

[0043] Secondly, it can effectively compensate for deviations caused by factors such as projector movement, installation errors, and lens distortion, and achieve high-precision projection positioning.

[0044] At the same time, each time the projector is moved to a new position, the calibration process can be completed automatically without manual intervention, which greatly shortens the preparation time and improves work efficiency.

[0045] In addition, it can easily cover different areas of large work surfaces or mold tables, solving the problem of limited fixed projection range. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0047] Figure 1 This is a structural diagram of the mobile DLP projection positioning system based on visual calibration;

[0048] Figure 2 Schematic diagram of the pilot projection calibration process of this mobile DLP projection positioning method based on visual calibration;

[0049] Figure 3 Schematic diagram of the segmented projection and cyclic correction process in the movable DLP projection positioning method based on visual calibration.

[0050] The following is a description of the components in the accompanying drawings:

[0051] 1. Projection unit 2. Working mold unit 3. Projection path 4. Image information 5. Moving unit 6. Calibration unit 7. Image acquisition unit. DETAILED DESCRIPTION

[0052] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations.

[0053] Due to structural and technical limitations, existing DLP projection technology cannot be applied to scenarios that require high-precision projection of long strips or large-format image information over a large area. To address the problems existing in existing DLP projection technology, the present invention provides a movable DLP projection positioning system and method based on visual calibration. By enabling the projection device to be moved to easily cover different areas of a large work surface or mold platform, the system solves the problem of limited fixed projection range.

[0054] Secondly, by moving the projection device to perform segmented projection and independently performing precise visual calibration on each segment, the accuracy loss and distortion problems of single large-scale projection are effectively overcome, and high-precision projection of the overall large-size image can be achieved in a splicing manner.

[0055] At the same time, using a fixed, specially marked ruler as an absolute reference and combining it with a camera for closed-loop visual feedback calibration can effectively compensate for deviations caused by factors such as projector movement, installation errors, and lens distortion, achieving high-precision projection positioning.

[0056] In addition, each time the projector is moved to a new position, the calibration process can be completed automatically without manual intervention, greatly shortening preparation time and improving work efficiency.

[0057] The present invention provides a movable DLP projection positioning system based on visual calibration, see Figure 1 It includes a projection unit 1, a moving unit 5, an image acquisition unit 7, a calibration unit 6, a working mold unit 2 and a control processing unit.

[0058] The mobile unit 5 is movably connected to the projection unit 1, and the projection unit 1 can move laterally along the mobile unit 5. The projection unit 1 can move on the mobile unit 5, and can easily cover different areas of a large work surface or mold table, solving the problem of limited fixed projection range.

[0059] As an example, the movable unit 5 here includes a guide rail assembly and a sliding connector. One end of the sliding connector is arranged in the guide rail assembly and can move laterally along the guide rail assembly. The other end of the sliding connector is connected to the projection unit 1 and can synchronously drive the projection unit 1 to move laterally along the guide rail assembly.

[0060] Here, the mobile unit 5 includes but is not limited to the above-mentioned components and structures, and the specific structure can be determined according to actual conditions.

[0061] The projection unit 1 exchanges data with the control processing unit, generates and projects image information through the control of the control processing unit, and its projection path 3 is arranged relative to the working mold table unit 2. The working mold table unit 2 is used to carry the workpiece or serve as a projection target. The image information 4 is projected onto the working mold table unit 2 through the projection unit 1.

[0062] The calibration unit 6 is fixedly installed on the edge of the working mold unit 2 near the projection unit 1. It has multiple predefined and easy-to-identify special physical marking points on it, which serve as a spatial position reference for the subsequent calibration of the projection unit 1. Its marking points cover the entire or most of the working range projected by the projection unit.

[0063] There is no limitation on the composition of the calibration unit here. For example, it can be a ruler with several physical marking points pre-marked on the ruler, such as T1, T2...Tn, as specific target marking points of the target projection position, so as to be used to calibrate the target projection position.

[0064] The image acquisition unit 7 is arranged relative to the projection unit 1 and can move along with the projection unit 1. The field of view can cover part of the scale and the projection area, and is used to simultaneously capture the marking points on the scale and the test projection points formed by the projection unit projected onto the surface of the working mold table unit 2.

[0065] The composition of the image acquisition unit 7 is not limited in this solution. For example, it can be a camera, which can simultaneously observe the specific target marking points on the scale of each projection area and the test projection points formed by the projection unit projected onto the surface of the mold stage unit.

[0066] This solution uses a fixed, specially marked ruler as an absolute reference and combines it with a camera for closed-loop visual feedback calibration. It can effectively compensate for deviations caused by factors such as projector movement, installation errors, and lens distortion, achieving high-precision projection positioning.

[0067] The image acquisition unit 7 exchanges data with the control processing unit, and transmits the observed specific target marking point and the test projection point formed by the projection unit 1 projected onto the surface of the working mold platform unit 2 to the control processing unit.

[0068] The control processing unit is used to calibrate the deviation caused by the movement, installation error and lens distortion of the projection unit 1 to achieve high-precision projection positioning. The control processing unit includes a receiving module, a data processing module and a control module.

[0069] The receiving module is used to receive the specific target marking points collected by the image acquisition unit 7 and the trial projection points formed by the projection unit 1 projected onto the surface of the working mold platform unit 2.

[0070] The receiving module exchanges data with the data processing module. The receiving module transmits the specific target marking points captured by the image acquisition unit and the test projection points formed by projection unit 1 projected onto the surface of the work platform unit 2 to the data processing module. The data processing module first calculates the actual projection deviation of the test projection points formed by projection unit 1 projected onto the surface of the work platform unit 2 relative to the specific target marking points and calculates the geometric correction parameters based on the deviation. As a result, the calibration process is automatically completed each time the projector moves to a new position, eliminating the need for manual intervention, significantly reducing preparation time and improving work efficiency.

[0071] The control module interacts with the data processing module and the projection unit 1 respectively. The control module controls the projection unit 1 according to the parameters to accurately project the corrected segmented image to a predetermined position on the working mold platform unit.

[0072] Based on the above scheme, the movable DLP projection positioning system based on visual calibration is constructed. This scheme also provides a movable DLP projection positioning method based on visual calibration. This method divides the large-size image to be projected into multiple segments suitable for single projection, and plans the projection movement position corresponding to each segment and the scale mark points used for calibration. Then, the projection device is moved to the predetermined position and the projection segment is projected. The camera collects the projection test points of the segment and the scale mark points associated with the segment position. The projection position of the projection device is calibrated by calculating the deviation between the projection test points and the scale mark points corresponding to the segment position, so that it is accurately projected to the predetermined position of the mold platform. The specific steps of this method are as follows:

[0073] S1: Projection image segmentation and position coordinate planning

[0074] S11: Segment the projected overall target image.

[0075] This step is used to divide the whole image into N image segments S1, S2, ... S according to the effective field of view of the projector, the required accuracy and the optional overlap. N (like Figure 3 Thus, high-precision projection of an overall large-scale image can be achieved through splicing.

[0076] S12: Determine the target physical position of the projector on the guide rail during segmented projection according to the segmented image formed in S11.

[0077] This step is used to generate each segment (S k) Determine the target physical position of the projector on the guide rail corresponding to its ideal center projection position (P osk ).

[0078] S13: Pre-mark on the ruler the reference point to which each segmented image actually corresponds when projected onto the mold platform.

[0079] This step is used to generate each segment (S k )(or its corresponding position P osk ) is associated with a set of special marking points on the ruler near the position that can be clearly and stably observed by the camera (for example, see Figure 3 , S1 is associated with T1 and T2; S2 is associated with T2 and T3, etc.).

[0080] S2: Based on the planning of S1 position coordinates, load the camera intrinsic parameters and the precise world coordinates of all scale markers.

[0081] S3: Based on the target physical position determined in S12, initialize the moving projector to the target position of the target segment.

[0082] This step is used to control the projector to move to the target segment (S k ) corresponds to the target position on the guide rail (P osk ).

[0083] S4: Start targeting segment (S k ) calibration procedure.

[0084] S5: Control the projector to test project the target segmented pattern

[0085] This step is used to control the projector to project the image containing the known projector coordinates (u i ,v i )’s test feature points (P k,i′ )’s target segment pattern.

[0086] S6: Capture and process the image of the pattern projected by S5

[0087] S61: Command the camera to capture an image.

[0088] S62: Identify the segmented pattern in the image (S k ) associated with the ruler mark point (T k,j )'s image coordinates.

[0089] S63: Identify the test feature points (P k,i′ )'s image coordinates.

[0090] The above-mentioned use of a fixed, specially marked ruler as an absolute reference, combined with a camera for closed-loop visual feedback calibration, can effectively compensate for deviations caused by factors such as projector movement, installation errors, and lens distortion, and achieve high-precision projection positioning.

[0091] S7: coordinate mapping and error determination of the segmented image captured by S6 (see Figure 2 )

[0092] S71: Using camera internal parameters and ruler mark points (T k,j ) of the known world coordinates, and establish a mapping from the image at the current position to the world coordinates.

[0093] S72: Test feature point (P k,i′ ) is mapped to the world coordinates to obtain its actual projected world coordinates (X′ P′k,i ,Y′ P′k,i ).

[0094] S73: Calculate the test feature point (P k,i′ ) relative to its corresponding S71 theoretical target world coordinates (which should eventually be associated with the T k,j The deviation vector Δ of the alignment k,i .

[0095] Deviation vector Δ k,i , is to test the feature points (P k,i′ ) and the ruler mark point (T k,j ), for each "trial projection point", the theoretical target world coordinates to which it should be accurately projected have been defined in the planning stage (S1), so in the actual process, the "trial projection point" should be aligned with the ruler mark point.

[0096] As an example, in world coordinates, the test feature point (P k,i′ ) is (X′ P′k,i ,Y′ P′k,i ), ruler mark point (T k,j ) is (X′ T′k,i ,Y′ T′k,i ),

[0097] Deviation vector Δ k,i The calculation formula is Δ k,i =(X′ T′k,i -X′ P′k,i ,Y′ T′k,i -Y′ P′k,i ), that is, deviation vector = (X coordinate of theoretical target - X coordinate of actual projection, Y coordinate of theoretical target - Y coordinate of actual projection).

[0098] This calculation method converts the information captured by the image sensor into quantitative physical deviations in the world coordinate system, thus providing a direct and precise basis for realizing automatic closed-loop visual feedback calibration and subsequent comprehensive compensation of various geometric errors (such as projector posture, lens distortion, motion error, etc.) through image pre-distortion.

[0099] S8: Solve the correction transformation for the deviation vector calculated in S7

[0100] This step is used to utilize multiple pairs (u i ,v i ) and (X′ P′k,i ,Y′ P′k,i )(or deviation Δ k,i ), solve the correction transformation H that accurately maps the projector coordinates to the world coordinates (or compensates for the deviation) at the current position k-1 .

[0101] H k-1 It is to solve a transformation that maps the target world coordinates to the internal image coordinates of the projector. Therefore, when solving, the known projector coordinates (u i ,v i ) and their actual world coordinates (X′ P′k,i ,Y′ P′k,i ) to inversely find this mapping.

[0102] Using the relationship between all the collected world coordinates and the internal coordinates of the projector, a mathematical method is preferably used to find an optimal overall matching solution to "calculate" the "conversion rule" Hk-1, for example, in the case of translation

[0103] Projector point (add a coordinate to indicate translation): [ui,vi,1]^T

[0104] World point: [X,Y,1]^T

[0105] The translation matrix Hk-1 is:

[0106] Hk-1=[[1,0,Tx],

[0107] [0,1,Ty],

[0108] [0,0,1]]

[0109] Tx and Ty are Δ k,i The two components of

[0110] This method can simultaneously compensate for multiple geometric errors and adapt to the new position of the projector by solving a single correction transformation Hk-1 from the actual measurement data, and automatically complete the calibration process, thereby achieving automated high-precision image projection.

[0111] S9: Pre-distort the current image segment using the correction transformation solved in S8 and generate a corrected segmented image.

[0112] S91: Get segment S k image content.

[0113] S92: To S k All points on (X target ,Y target ) Apply the inverse transform H k-1 Calculate the corresponding projector coordinates (u,v).

[0114] S93: Generate the corrected segmented image S based on the projector coordinates calculated in S92 k′ .

[0115] S10: Project the segmented image corrected in S9

[0116] This step is used to control the projector to send the corrected segmented image S k′ Projected onto the working mold table.

[0117] S11: The projector moves to the next segment position and performs the above S2-S10 operations. (See Figure 3 )

[0118] The movable DLP projection positioning method based on visual calibration constituted by the above-mentioned scheme is illustrated below with an example of its working process in specific application. It should be noted here that the working process is only an example, and the parameter application and operation scheme therein do not constitute a limitation to this scheme.

[0119] For example, a long mold is projected in sections. The mold is 3 meters long, and the projector projects 1 meter at a time. Six points are marked on the ruler (T_0.25 to T_2.75, one every 0.5 meters).

[0120] 1. Planning:

[0121] Image segmentation (ImgSeg): 3 segments, no overlap.

[0122] ImgSeg_1: covers the area from 0.0m to 1.0m of the mold.

[0123] ImgSeg_2: covers the area from 1.0m to 2.0m of the mold.

[0124] ImgSeg_3: covers the area from 2.0m to 3.0m of the mold.

[0125] Projection position (ProjPos): 3 (ProjPos_1, ProjPos_2, ProjPos_3), accurately corresponding to each image segment.

[0126] Associated ruler points: Each ProjPos is associated with at least two ruler marking points within its field of view for calibration.

[0127] ProjPos_1 (0-1m projection): associated with T_0.25, T_0.75

[0128] ProjPos_2 (1-2m projection): associated with T_1.25, T_1.75

[0129] ProjPos_3 (2-3m projection): associated with T_2.25, T_2.75

[0130] 2. Implementation:

[0131] Segment 1: Projection ImgSeg_1 (0.0-1.0m, at ProjPos_1)

[0132] Move and load (S2-S3): Projector to ProjPos_1. Load camera parameters and world coordinates of all 6 ruler points.

[0133] Automatic calibration (S4-S8):

[0134] Test projection (S5): Project a test point.

[0135] Visual capture and mapping (S6-S7): Camera capture, identification of associated scale points (such as T_0.25, T_0.75) and test points, and calculation of the actual world coordinates of the test points.

[0136] Solve the correction transformation (S8): Calculate the first correction transformation matrix: H_inv_1.

[0137] Pre-distortion and precise projection (S9-S10):

[0138] Use H_inv_1 to pre-distort ImgSeg_1 and generate ImgSeg_1_corrected.

[0139] Projection ImgSeg_1_corrected.

[0140] Segment 2: Projection ImgSeg_2 (1.0-2.0m, at ProjPos_2)

[0141] Move (S11, S3): Projector to ProjPos_2.

[0142] Automatic calibration (S4-S8): (Use the scale points associated with ProjPos_2 such as T_1.25, T_1.75)

[0143] Calculate the second correction transformation matrix: H_inv_2.

[0144] Pre-distortion and precise projection (S9-S10):

[0145] Use H_inv_2 to pre-distort ImgSeg_2 and generate ImgSeg_2_corrected.

[0146] Projection ImgSeg_2_corrected.

[0147] Segment 3: Projection ImgSeg_3 (2.0-3.0m, at ProjPos_3)

[0148] Move (S11, S3): Projector to ProjPos_3.

[0149] Automatic calibration (S4-S8): (Use the scale points associated with ProjPos_3 such as T_2.25, T_2.75)

[0150] Calculate the third correction transformation matrix: H_inv_3.

[0151] Pre-distortion and precise projection (S9-S10):

[0152] Use H_inv_3 to pre-distort ImgSeg_3 and generate ImgSeg_3_corrected.

[0153] Projection ImgSeg_3_corrected.

[0154] The aforementioned methods, or specific system units, or portions thereof, of the present invention are purely software-based and can be implemented as program code on physical media, such as a hard drive, optical disk, or any electronic device (e.g., a smartphone or computer-readable storage medium). When a machine loads and executes the program code (e.g., a smartphone), the machine becomes a device for implementing the present invention. The aforementioned methods and devices of the present invention can also be transmitted in program code form via some transmission medium, such as a cable, optical fiber, or any other transmission method. When the program code is received, loaded, and executed by a machine (e.g., a smartphone), the machine becomes a device for implementing the present invention.

[0155] The movable DLP projection positioning system and method based on visual calibration composed of the above-mentioned scheme can effectively overcome the accuracy loss and distortion problems of single large-scale projection by segmented projection and independent precise visual calibration of each segment, and can achieve high-precision projection of the overall large-size image in a splicing manner.

[0156] Secondly, using a fixed, specially marked ruler as an absolute reference and combining it with a camera for closed-loop visual feedback calibration can effectively compensate for deviations caused by factors such as projector movement, installation errors, and lens distortion, achieving high-precision projection positioning.

[0157] At the same time, each time the projector is moved to a new position, the calibration process can be completed automatically without manual intervention, which greatly shortens the preparation time and improves work efficiency.

[0158] In addition, the projector can be moved on the guide rail to easily cover different areas of a large work surface or mold table, solving the problem of limited fixed projection range.

[0159] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A movable DLP projection positioning system based on visual calibration, comprising a projection unit and a working mold platform unit, wherein the projection path of the projection unit is arranged relative to the working mold platform unit, characterized in that: It also includes a moving unit, an image acquisition unit, a calibration unit and a control processing unit; the moving unit is movably connected to the projection unit, and the projection unit can move laterally along the moving unit; the calibration unit is installed at the edge of the working mold platform unit close to the projection unit, and has a plurality of predefined and easy-to-identify special physical marking points on it; the image acquisition unit is arranged in a relative position to the projection unit, and can move with the projection unit to simultaneously capture the marking points on the calibration unit and the test projection points formed by the projection unit projected onto the surface of the working mold platform unit; the control processing unit interacts with the projection unit and the image acquisition unit for data respectively.

2. The mobile DLP projection positioning system based on visual calibration according to claim 1, characterized in that: The control processing unit includes a receiving module, a data processing module and a control module; The receiving module is used to receive the specific target marking points collected by the image acquisition unit and the trial projection points formed by the projection unit projected onto the surface of the working mold platform unit; the receiving module interacts with the data processing module for data, and the receiving module transmits the received specific target marking points and the trial projection points projected onto the surface of the working mold platform unit to the data processing module, and the data processing module first calculates the actual projection deviation of the trial projection points formed by the projection unit projected onto the surface of the working mold platform unit relative to the specific target marking points, and calculates the geometric correction parameters based on the deviation; the control module interacts with the data processing module and the projection unit for data respectively, and the control module controls the projection unit according to the parameters to accurately project the corrected segmented image to a predetermined position on the working mold platform unit.

3. A method for positioning a movable DLP projection based on visual calibration, wherein the method is implemented in conjunction with the method for positioning a movable DLP projection based on visual calibration according to claims 1-2, and is characterized in that: The movable DLP projection positioning method based on visual calibration includes the following steps: S1: Planning of projection image segmentation and position coordinates; S2: Load the camera intrinsic parameters and the precise world coordinates of all scale markers based on the planning of S1 position coordinates; S3: Based on the target physical position determined in S1, initialize the mobile projector to the target position of the target segment; S4: Start the segmented calibration procedure; S5: Control the projector to test project the target segmented pattern; S6: Capturing and processing the segmented pattern projected by S5; S7: performing coordinate mapping and error determination on the segmented image captured by S6; S8: solving a correction transformation for the error vector calculated in S7; S9: pre-distorting the current image segment using the correction transformation solved in S8 and generating a corrected segmented image; S10: Control the projector to project the corrected segmented image onto the working mold platform; S11: The projector moves to the next segmented position and performs the above operations S2-S10.

4. The method for positioning a movable DLP projection system based on visual calibration according to claim 3, wherein: The S1 comprises the following steps: S11: Segment the entire image according to the effective field of view of the projector, the required accuracy, and the optional overlap; S12: determining the target physical position of the projector on the guide rail during segmented projection according to the segmented image formed in S11; S13: Pre-mark on the ruler the reference point to which each segmented image actually corresponds when projected onto the mold platform.

5. The method for positioning a movable DLP projection system based on visual calibration according to claim 3, wherein: The S6 comprises the following steps: S61: command the camera to capture an image; S62: Identify the image coordinates of the scale mark points associated with the segmented pattern in the image; S63: Identify the image coordinates of the test feature points projected by the projector in the image.

6. The method for positioning a movable DLP projection system based on visual calibration according to claim 3, wherein: The S7 comprises the following steps: S71: Using the camera intrinsic parameters and the known world coordinates of the scale mark points, establish an image-to-world coordinate mapping at the current position; S72: Mapping the image coordinates of the test feature point to the world coordinates to obtain its actual projected world coordinates; S73: Calculate the deviation vector of the test feature point relative to its corresponding theoretical target world coordinates in S71.

7. The method for positioning a movable DLP projection system based on visual calibration according to claim 3, wherein: In the S8, a plurality of pairs of theoretical target world coordinates and actual projected world coordinates or deviations are used to solve a correction transformation for accurately mapping the projector coordinates to the world coordinates or compensating for the deviation at the current position.

8. The method for positioning a movable DLP projection system based on visual calibration according to claim 3, wherein: The S9 comprises the following steps: S91: Obtain segmented image content; S92: Apply inverse transformation to all actual projected world coordinates on the segmented image to calculate the corresponding projector coordinates; S93: Generate a corrected segmented image based on the projector coordinates calculated in S92.

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