A line structured light measuring device and method for complex highlight surfaces

Abstract

This invention provides a line structured light measurement device and method for complex, high-brightness surfaces, belonging to the field of laser measurement technology. It includes a frame, a camera mounted on the frame, and a line laser emitter. The line laser emitter is adapted to emit light and direct it towards the object under test, and the camera is adapted to photograph the object. The line structured light measurement device also includes a light-shielding plate. The light-shielding plate is horizontally positioned below the line laser emitter, and rotates around its axis in conjunction with the frame. The light-shielding plate has an arc-shaped light-transmitting groove, adapted to divide the light strips illuminating the upper surface of the light-shielding plate into several segments. The frame is equipped with a driving component adapted to drive the rotation of the light-shielding plate. During the rotation of the light-shielding plate, the several light strips can be separately illuminated onto the object under test. By rotating the light-shielding plate, the several light strips can be separately illuminated onto the object under test, thus reducing the impact of reflection from complex, high-brightness surfaces on the camera's image quality.

Description

Technical Field

[0001] This invention belongs to the field of laser measurement technology, specifically relating to a line structured light measurement device and method for complex high-brightness surfaces. Background Technology

[0002] A line structured light sensor mainly consists of a camera and a line laser emitter, enabling three-dimensional measurement of objects. The object is illuminated by light emitted from the line laser emitter, and the camera then captures an image of the object, thus achieving the purpose of measurement. The working principle of the line structured light sensor is existing technology and will not be elaborated upon here.

[0003] However, when the entire beam of light from an online laser emitter illuminates a complex, highly reflective object surface, the surface will reflect and scatter the light multiple times, thus affecting the quality of the camera's image. It should be noted that a complex, highly reflective object surface refers to an object surface that is easily reflective and has an uneven surface. Summary of the Invention

[0004] This invention provides a line structured light measurement device and method for complex, high-brightness surfaces, aiming to reduce the impact of light reflected from the surface of high-brightness objects on camera image quality.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A line structured light measurement device for complex, high-brightness surfaces is provided, comprising a frame, a camera mounted on the frame, and a line laser emitter. The line laser emitter is adapted to emit light and direct it toward the object under test, and the camera is adapted to photograph the object under test. The line structured light measurement device further includes:

[0007] A light shield is horizontally positioned below the online laser emitter, and the light shield rotates around its axis in conjunction with the frame. The light shield has an arc-shaped light-transmitting groove, which is suitable for dividing the light strips illuminating the upper surface of the light shield into several segments.

[0008] The frame is equipped with a drive component suitable for rotating the light-shielding plate; during the rotation of the light-shielding plate, several light strips can be directed onto the object to be tested.

[0009] In one possible implementation, the calculation formula for the arc-shaped light-transmitting groove on the light-shielding plate is:

[0010]

[0011] A planar coordinate system is established with the center of the light-shielding plate as the center, where (x, y) are the coordinates of the point before rotation, (x1, y1) are the coordinates of the point after rotation, and the rotation angle is θ. Based on the length of the light strip on the light-shielding plate and the position of the light strip corresponding to the light strip after the light-shielding plate is rotated, the coordinates of all light-transmitting positions on the light-shielding plate are determined. Through slots are set at all coordinate positions on the light-shielding plate to form arc-shaped light-transmitting through slots, so that the light strip on the light-shielding plate can illuminate the object to be tested in segments.

[0012] In one possible implementation, the light strip on the light-shielding plate is divided into several square segments, and the four corner points of each square segment can determine the position of a slot; the positions of all square segments on the rotated light-shielding plate are calculated using the above formula, and the corresponding coordinate points are smoothly connected to obtain an arc-shaped light-transmitting slot.

[0013] In one possible implementation, the width of the light strip on the light-shielding plate is greater than the width of the arc-shaped light-transmitting groove.

[0014] In one possible implementation, a housing is connected to the frame, and the camera, the line laser emitter, the drive unit, and the light shield are all disposed within the housing; the bottom of the housing has a first through hole and a second through hole, the emitting end of the line laser emitter faces the first through hole, and the shooting end of the camera faces the second through hole;

[0015] In this system, a light strip passing through an arc-shaped light-transmitting groove illuminates the object under test through a first through-hole, and the camera's imaging end captures images of the object under test through a second through-hole.

[0016] In one possible implementation, lenses are provided on both the first through hole and the second through hole, and the lenses are mounted on the housing via a mounting structure.

[0017] In one possible implementation, the bottom of the first through hole has a first mounting hole, the diameter of which is larger than that of the first through hole; the bottom of the second through hole has a second mounting hole, the diameter of which is larger than that of the second through hole; and the two lenses are respectively adapted to be placed on the first mounting hole and the second mounting hole.

[0018] The mounting structure includes a mounting ring, which is detachably connected to the housing; the inner peripheral wall of the mounting ring has a support ring suitable for supporting the bottom edge of the lens.

[0019] In this embodiment, the frame is fixed on the workbench, the object to be tested is placed on the workbench and located below the line laser emitter; the line laser emitter emits light onto the upper surface of the light shield, forming a light strip on the upper surface of the light shield; the light shield is driven to rotate by the drive component, so that the arc-shaped light-transmitting groove coincides with different segments on the light strip, thereby allowing different segments of the light strip to illuminate the object to be tested, and the object to be tested is photographed by the camera.

[0020] The present invention provides a line structured light measurement device for complex high-brightness surfaces. Compared with the prior art, by rotating the light shield, several light strips can be separately irradiated onto the object to be measured, thus reducing the impact of reflection from complex high-brightness surfaces on camera image quality.

[0021] To achieve the above objectives, another technical solution adopted by the present invention is:

[0022] A measurement method for a line structured light measurement device using the aforementioned complex high-brightness surface is provided, comprising the following steps:

[0023] A line laser emitter emits a laser beam onto the upper surface of the light-shielding plate, forming a light stripe on the upper surface of the light-shielding plate; as the light-shielding plate rotates, the arc-shaped light-transmitting groove divides the light stripe into several small segments;

[0024] The light-shielding plate rotates at a preset angle so that the next segment of light strip can illuminate the object under test; the light-shielding plate repeats the rotation process until all the segments of light strip on the light-shielding plate illuminate the object under test; the camera takes a picture of the object under test when each segment of light strip illuminates the object under test.

[0025] In one possible implementation, the camera captures an image of the object under test when the light-blocking plate is rotated to an opaque position, and uses the image as a mask.

[0026] In one possible implementation, the edge of the object to be tested in the mask image is a line with alternating light and dark areas. The image processing module preprocesses the edge lines of the object to be tested. If the pixel value of the edge lines of the object to be tested is greater than a preset value, the image processing module sets the pixel value at the above position to 255. If the pixel value of the edge lines of the object to be tested is less than the preset value, the image processing module sets the pixel value at the above position to 0.

[0027] The measurement method of the line structured light measurement device for complex high-brightness surfaces provided by the present invention has the same beneficial effects as the line structured light measurement device for complex high-brightness surfaces, and will not be repeated here. Attached Figure Description

[0028] Figure 1 A schematic diagram of a line structured light measurement device for a complex high-brightness surface provided in an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of the mounting ring portion of a line structured light measurement device for a complex high-brightness surface provided in an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the light-shielding plate portion of a line structured light measurement device for a complex high-brightness surface provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram illustrating the calculation process of an arc-shaped light-transmitting slot for a line structured light measurement device on a complex high-brightness surface, provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram illustrating the use of a laser emitter and camera in conjunction with existing technology.

[0033] Explanation of reference numerals in the attached drawings: 1. Camera; 2. Line laser emitter; 3. Light shield; 31. Arc-shaped light-transmitting groove; 32. Boss; 4. Drive component; 5. Housing; 51. First through hole; 52. Second through hole; 53. Lens; 54. Mounting ring; 55. Mounting plate; 56. L-shaped bracket; 6. Laser plane. Detailed Implementation

[0034] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0035] Please refer to the following: Figures 1 to 5 The present invention provides a line structured light measurement device for complex high-brightness surfaces. The device includes a frame (not shown in the figure), a camera 1 mounted on the frame, and a line laser emitter 2. The line laser emitter 2 is adapted to emit light and direct it toward the object under test, and the camera 1 is adapted to photograph the object under test. The device also includes a light-shielding plate 3, which is horizontally positioned below the line laser emitter 2 and rotates around its axis in conjunction with the frame. The light-shielding plate 3 has an arc-shaped light-transmitting groove 31, which is adapted to divide the light strips illuminating the upper surface of the light-shielding plate 3 into several segments. The frame is equipped with a driving component 4 adapted to drive the light-shielding plate 3 to rotate. During the rotation of the light-shielding plate 3, the several light strips can be directed onto the object under test.

[0036] In this embodiment, the frame is fixed to the workbench, and the object to be tested is placed on the workbench, below the line laser emitter 2. The line laser emitter 2 emits light onto the upper surface of the light-shielding plate 3, forming a light strip on the upper surface of the light-shielding plate 3. The light-shielding plate 3 is rotated by the driving component 4, so that the arc-shaped light-transmitting groove 31 coincides with different segments of the light strip, thereby allowing different segments of the light strip to illuminate the object to be tested, and the object to be tested is photographed by the camera 1. Since the surface of the object to be tested is a complex, high-gloss surface, there will be multiple reflections after the light shines on the surface of the object to be tested, which will seriously affect the image quality of the camera. The above-mentioned arrangement in this application can reduce the influence of reflected light and improve the image quality. It should be noted that the line laser emitter 2 and the camera 1 are existing technologies and will not be described in detail here.

[0037] This invention provides a line structured light measurement device for complex, high-brightness surfaces. Compared with existing technologies, by rotating the light-shielding plate 3, several light strips can be separately irradiated onto the object under test, thus reducing the impact of reflection from the complex, high-brightness surface on the image quality of the camera 1. Through this setup, the lengths of the light strips projected onto the object under test are approximately equal. The process does not alter the surface formed by the light emitted from the line laser emitter 2, i.e., it does not change the laser plane 6; it simply allows the light to be projected onto the object under test in segments, therefore it does not affect the measurement accuracy.

[0038] In some embodiments, such as Figure 1 As shown, a housing 5 is connected to the frame, and the camera 1, line laser emitter 2, drive unit 4, and light shield 3 are all located inside the housing 5. The bottom of the housing 5 has a first through hole 51 and a second through hole 52. The emitting end of the line laser emitter 2 faces the first through hole 51, and the shooting end of the camera 1 faces the second through hole 52. The light strip passing through the arc-shaped light-transmitting groove 31 illuminates the object to be tested through the first through hole 51, and the shooting end of the camera 1 captures the object to be tested through the second through hole 52.

[0039] For example, the line laser emitter 2 is perpendicular to the bottom of the housing 5, so that the light can be perpendicularly irradiated onto the object to be measured; the vertical direction of the light strip on the light shield 3 passes through the center of the light shield 3. The power component includes a stepper motor, and an L-shaped bracket 56 is fixedly provided inside the housing 5, on which the stepper motor is fixed; the center position of the light shield 3 has a boss 32, which is adapted to be inserted and engaged with the output shaft of the stepper motor; the outer peripheral wall of the output shaft of the stepper motor has a threaded hole, and the outer peripheral wall of the boss 32 has a through hole aligned with the threaded hole; by passing a bolt through the through hole on the boss 32 and threading it into the threaded hole on the motor output shaft, the boss 32 can be fixed on the output shaft of the stepper motor.

[0040] For example, both the first through hole 51 and the second through hole 52 are provided with lenses 53, which are mounted on the housing 5 via a mounting structure. The lens 53 in the first mounting hole is a square lens 53, and the lens 53 in the second mounting hole is a circular lens 53; the square lens corresponds to the line laser emitter, and the circular lens corresponds to the camera. The bottom of the first through hole 51 has a first mounting hole, the diameter of which is larger than that of the first through hole 51; the bottom of the second through hole 52 has a second mounting hole, the diameter of which is larger than that of the second through hole 52; the two lenses 53 are respectively adapted to be placed on the first mounting hole and the second mounting hole; the mounting structure includes a mounting ring 54, which is detachably connected to the housing 5; the inner peripheral wall of the mounting ring 54 has a support ring suitable for supporting the bottom edge of the lens 53.

[0041] Both the square lens 53 and the circular lens 53 mentioned above are planar lenses 53. The width of the light strip on the light-shielding plate 3 is greater than the width of the arc-shaped light-transmitting groove 31.

[0042] With the above-described configuration of this embodiment, the lens 53 can be mounted on the first mounting hole and the second mounting hole; after the lens 53 is mounted, impurities entering the housing 5 through the first through hole 51 and the second through hole 52 can be reduced, thereby reducing impurities adhering to the optical element. The optical element includes a line laser emitter 2 and a camera 1.

[0043] It should be noted that the housing 5 is composed of six mounting plates 55 spliced ​​together. Adjacent mounting plates 55 can be fixed with angle irons and bolts; alternatively, threaded holes can be provided on the side of the mounting plates 55, allowing two mounting plates 55 to be directly connected by bolts. After the housing 5 is assembled, the housing 5 is a closed space.

[0044] In some embodiments, such as Figures 1 to 5 As shown, the calculation formula for the arc-shaped light-transmitting groove 31 on the light-shielding plate 3 is:

[0045]

[0046] A planar coordinate system is established with the center of the light-shielding plate 3 as the center, (x,y) is the coordinate of the point before rotation, (x1,y1) is the coordinate of the point after rotation, and the rotation angle is θ. Based on the length of the light strip on the light-shielding plate 3 and the position of the light strip after the light-shielding plate 3 is rotated, the coordinates of all light-transmitting positions on the light-shielding plate 3 are determined, and through slots are set at all coordinate positions of the light-shielding plate 3 to form an arc-shaped light-transmitting through slot 31 so that the light strip on the light-shielding plate 3 can illuminate the object to be measured in segments.

[0047] For example, the light strip on the light shield 3 is divided into several square segments, and the four corner points of each square segment can determine the position of a slot; the positions of all square segments on the rotated light shield 3 are calculated by the above formula, and the corresponding coordinate points are smoothly connected to obtain the arc-shaped light-transmitting slot 31.

[0048] Specifically, assuming each slot on the light-shielding plate 3 is a square, after determining the distance between the line laser emitter 2 and the light-shielding plate 3, the stepper motor rotates at a fixed angle each time. The coordinates of the four points after the first rotation of the light-shielding plate 3 can be calculated using the above formula, and the position of the second slot can be determined based on these coordinates. The coordinates of the four points after the second rotation of the light-shielding plate 3 can be calculated using the same formula, and the position of the third slot can be determined based on these coordinates. This process is repeated until the positions of all slots are determined. Then, the two upper and two lower points of each slot are smoothly connected by arcs to obtain the final shape of the slot, which consists of two continuous arcs, i.e., an arc-shaped light-transmitting slot 31.

[0049] Specifically, MATLAB software can be used for simulation analysis. First, the positions of the line laser emitter 2 and the light shield 3, the rotation angle of the light shield 3 each time, the side length of the square groove, and the length of the line structured light stripe illuminating the surface of the object to be tested are set. By running the program, a continuous arc can be obtained.

[0050] Based on the same inventive concept, the present invention also provides a measurement method for a line structured light measurement device using the aforementioned complex high-brightness surface, comprising the following steps:

[0051] The line laser emitter 2 emits a laser beam onto the upper surface of the light shield 3, forming a light stripe on the upper surface of the light shield 3. The arc-shaped light-transmitting groove 31 can divide the light stripe into several segments during rotation. The light shield 3 rotates at a preset angle so that the next segment of the light stripe can illuminate the object to be tested. The light shield 3 repeats the rotation process until all the segments of the light stripe on the light shield 3 illuminate the object to be tested. When each segment of the light stripe illuminates the object to be tested, the camera 1 takes a picture of the object to be tested.

[0052] In some embodiments, such as Figures 1 to 5 As shown, when the light-shielding plate 3 is rotated to an opaque position, the camera 1 captures the object under test, which is then used as a mask image. The edges of the object under test in the mask image are lines with alternating light and dark areas. The image processing module preprocesses these edges. If the pixel value of the edge lines is greater than a preset value, the image processing module sets the pixel value at that position to 255. If the pixel value is less than the preset value, the image processing module sets the pixel value at that position to 0. The image processing module is existing technology and will not be described in detail here.

[0053] For example, the captured mask image will be used for subsequent image processing. In the subsequent processing, the mask is represented as a two-dimensional matrix array, with all elements consisting of 0 and 1. The area where the object to be tested is located is 1, and other areas are 0.

[0054] Specifically, because the edges of the object under test in the mask image exhibit alternating light and dark areas, preprocessing is necessary before further processing to highlight these edges. The preprocessing involves using an image processing module to analyze the edge lines of the mask image. If the pixel value of the edge line is greater than a preset value, the pixel value of that area is set to 255 (white); if the pixel value is less than the preset value, the pixel value of that area is set to 0 (black). This setup ensures that the edges of the object under test in the mask image are clearly defined, facilitating subsequent processing.

[0055] It should be noted that before processing the object to be measured through the line laser emitter 2 and camera 1, camera 1 needs to be calibrated first, that is, the internal and external parameters of camera 1 need to be solved.

[0056] Specifically, a ceramic target calibration plate is used to solve for the intrinsic parameters of camera 1. The calibration plate is placed within the field of view of camera 1, and 15-20 images of the calibration plate in different poses are taken with camera 1. The Zhang Zhengyou calibration method is used to solve for the intrinsic parameters of camera 1. The extrinsic parameters of camera 1 are calculated using the Tsai two-step method. The extrinsic parameters of camera 1 mainly include the rotation matrix R and the translation vector T. The Tsai two-step method is existing technology and will not be elaborated here.

[0057] Specifically, before processing the object to be measured by the line laser emitter 2 and the camera 1, the laser plane must be calculated.

[0058] A ceramic target calibration plate is also needed for laser plane calibration. Camera 1 first takes an image of the calibration plate, then the line laser emitter 2 is turned on to illuminate the calibration plate with a light stripe. Camera 1 then takes another image of the calibration plate, and so on, completing a set of image captures. By changing the height of the calibration plate and taking three or more sets of calibration plate images using the above method, the equation of the laser plane can be calculated.

[0059] Specifically, before processing the object under test through the line laser emitter 2 and camera 1, it is necessary to establish a motion coordinate system. This is because the worktable on which the object under test is located is moved by a motor, so it is necessary to transform the three-dimensional data points from the camera 1 coordinate system to the motion coordinate system.

[0060] A ceramic target calibration plate is also used when solving for the motion coordinate system. The calibration plate is placed on the worktable, and camera 1 takes an image of the calibration plate. Then, the motor drives the worktable to move, and after moving a certain distance, camera 1 takes another image of the calibration plate. The initial position is called the first position, and the position after the movement is called the second position.

[0061] The lower left corner of the calibration plate in the first position is called the first coordinate point, the coordinate point above the lower left corner of the first position is called the second coordinate point, and the lower left corner of the calibration plate in the second position is called the third coordinate point.

[0062] By fitting these three coordinate points to a plane, we obtain the first plane. We then find the normal vector of the first plane through the first coordinate point and locate a point on the normal vector, which we call the fourth coordinate point. Finally, we fit the first, second, and fourth coordinate points to obtain the second plane. We then find the normal vector of the second plane through the first coordinate point and locate a point on the normal vector, which we call the fifth coordinate point. Finally, we fit the first, fourth, and fifth coordinate points to obtain the third plane. The first, second, and third planes are perpendicular to each other, thus completing the construction of the motion coordinate system.

[0063] In addition, the worktable includes a fixed base and a sliding stage. The frame is fixed on the fixed base, and the object to be measured is placed on the sliding stage. During the sliding process, the object to be measured and the frame can move relative to each other, so that the light strips can be irradiated on different positions of the object to be measured in sequence, thereby completing the overall measurement of the object to be measured; and the acquired image is further processed by the image processing module.

[0064] It should be noted that the stepper motor driving the sliding table and the stepper motor driving the light-shielding plate are two separate stepper motors. Driving the sliding table with stepper motors is existing technology, and the sliding table can be driven by a stepper motor and a screw, which will not be elaborated here.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A linear structured light measuring device for complex highlight surfaces, comprising a frame, a camera and a linear laser emitter mounted on the frame, the linear laser emitter being adapted to emit a light line and direct it towards an object to be measured, the camera being adapted to take a picture of the object to be measured; characterized in that, The line structured light measurement device also includes: A light shield is horizontally positioned below the online laser emitter, and the light shield rotates around its axis in conjunction with the frame. The light shield has an arc-shaped light-transmitting groove, which is suitable for dividing the light strips illuminating the upper surface of the light shield into several segments. The frame is equipped with a drive component suitable for rotating the light-shielding plate; during the rotation of the light-shielding plate, several light strips can be directed onto the object to be tested. The calculation formula for the arc-shaped light-transmitting groove on the light-shielding plate is: Wherein, the center position of the light shielding plate is taken as the center of the plane coordinate system, (x, y) is the coordinate of the point before rotation, (x1, y1) is the coordinate of the point after rotation, and the rotation angle is ; according to the length of the light bar on the light shielding plate and the position corresponding to the light bar after the rotation of the light shielding plate, the coordinates of all the light-transmitting positions on the light shielding plate are determined, and the through slot is arranged at all the coordinate positions of the light shielding plate and the arc-shaped light-transmitting through slot is formed, so that the light bar on the light shielding plate can be segmented to irradiate on the object to be measured.

2. A line-structured light measuring device for complex highlight surfaces as claimed in claim 1, characterized in that The light strip on the light-shielding plate is divided into several square segments. The four corner points of each square segment can be used to determine the position of a slot. The positions of all square segments on the rotated light-shielding plate are calculated using the above formula, and the corresponding coordinate points are smoothly connected to obtain the arc-shaped light-transmitting slot.

3. The line structured light measurement device for complex high-brightness surfaces as described in claim 1, characterized in that, The width of the light strip on the light-shielding plate is greater than the width of the arc-shaped light-transmitting groove.

4. The line structured light measurement device for complex high-brightness surfaces as described in claim 1, characterized in that, A housing is connected to the frame, and the camera, the line laser emitter, the drive unit, and the light shield are all housed within the housing. The bottom of the housing has a first through hole and a second through hole, with the emitting end of the line laser emitter facing the first through hole and the shooting end of the camera facing the second through hole. In this system, a light strip passing through an arc-shaped light-transmitting groove illuminates the object under test through a first through-hole, and the camera's imaging end captures images of the object under test through a second through-hole.

5. The line structured light measurement device for complex high-brightness surfaces as described in claim 4, characterized in that, Both the first through hole and the second through hole are provided with lenses, and the lenses are mounted on the housing by a mounting structure.

6. The line structured light measurement device for complex high-brightness surfaces as described in claim 5, characterized in that, The bottom of the first through hole has a first mounting hole, the diameter of which is larger than that of the first through hole; the bottom of the second through hole has a second mounting hole, the diameter of which is larger than that of the second through hole; the two lenses are respectively adapted to be placed on the first mounting hole and the second mounting hole; The mounting structure includes a mounting ring, which is detachably connected to the housing; the inner peripheral wall of the mounting ring has a support ring suitable for supporting the bottom edge of the lens.

7. A measurement method using the line structured light measurement device for complex high-brightness surfaces as described in any one of claims 1-6, characterized in that, Includes the following steps: A line laser emitter emits a laser beam onto the upper surface of the light-shielding plate, forming a light stripe on the upper surface of the light-shielding plate; as the light-shielding plate rotates, the arc-shaped light-transmitting groove divides the light stripe into several small segments; The light-shielding plate rotates at a preset angle so that the next segment of light strip can illuminate the object under test; the light-shielding plate repeats the rotation process until all the segments of light strip on the light-shielding plate illuminate the object under test; the camera takes a picture of the object under test when each segment of light strip illuminates the object under test.

8. The line structured light measurement method for complex high-brightness surfaces as described in claim 7, characterized in that, When the light-blocking plate is rotated to an opaque position, the camera captures the object under test and uses it as a mask image.

9. The line structured light measurement method for complex high-brightness surfaces as described in claim 8, characterized in that, The edges of the object to be tested in the mask image are lines with alternating light and dark areas. The image processing module preprocesses the edges of the object to be tested. If the pixel value of the edge of the object to be tested is greater than a preset value, the image processing module sets the pixel value at the above position to 255. If the pixel value of the edge of the object to be tested is less than the preset value, the image processing module sets the pixel value at the above position to 0.

Images