3D measurement system, method and device based on structured light and storage medium
By forming partially overlapping light spots on the object and constructing a grayscale ratio image, the problem of decreased measurement accuracy caused by uneven reflectivity is solved, and higher measurement accuracy is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LENS TECHNOLOGY CO LTD
- Filing Date
- 2026-01-09
- Publication Date
- 2026-04-21
AI Technical Summary
In high-precision measurement scenarios, the uneven reflectivity of the surface of the object being measured can lead to a decrease in measurement accuracy.
By outputting a first and a second beam of light parallel to each other to the object being measured, a first and a second light spot that partially overlap on the object are formed, two images are acquired, and a third image is constructed based on the gray value ratio of the pixels for 3D measurement.
It eliminates the influence of uneven reflectivity on the surface of the object being measured on the measurement results, thus improving the accuracy and precision of the measurement.
Smart Images
Figure CN121898293A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser measurement technology, and in particular to a 3D measurement system, method, device and storage medium based on structured light. Background Technology
[0002] Laser line structured light 3D measurement technology projects a narrow laser line to form a distinct structured light spot on the surface of an object. After capturing the image with a camera, image processing technology is used to identify the feature trajectory such as the maximum gray value point of the cross-section of the light spot, thereby realizing the coordinate transformation and shape measurement from two-dimensional to three-dimensional.
[0003] In related schemes, the structured light spot image is an image generated by the reflected light from the laser illuminating the object being measured, as observed by the camera. The gray value of each pixel is the product of the laser intensity at that point and the reflectivity of the object at that point. In high-precision measurement scenarios, scratches, dirt, or other defects on the surface of the object can lead to uneven reflectivity, meaning that the reflectivity varies at different locations on the object's surface. This directly affects the grayscale distribution of the acquired image, interfering with the structured light feature point recognition results and thus reducing measurement accuracy. Summary of the Invention
[0004] In view of this, the present invention provides a 3D measurement system, method, device and storage medium based on structured light to solve or partially solve the technical problem of decreased measurement accuracy caused by non-uniform reflectivity of the measured object.
[0005] The technical solution proposed in this invention is as follows: In a first aspect, the present invention provides a 3D measurement system based on structured light, comprising: The beam projection module is used to output a first outgoing beam and a second outgoing beam in parallel directions to the object under test. The first outgoing beam and the second outgoing beam form a first light spot and a second light spot on the object under test, respectively, and the first light spot and the second light spot partially overlap. An image acquisition device, with its shooting direction pointing towards the object being measured, is used to acquire a first image including a first light spot and a second image including a second light spot; The processor is connected to the image acquisition unit, receives the first image and the second image acquired by the image acquisition unit, constructs a third image based on the ratio of the gray values of the pixels in the first image to the gray values of the corresponding pixels in the second image, and performs 3D measurement on the object under test based on the third image.
[0006] In some alternative implementations, the beam projection module includes: The first line of structured light source has its beam output end facing the beam displacement adjustment component. A beam displacement adjustment component is disposed in the output optical path of the first linear structured light source and located between the first linear structured light source and the object under test. The beam displacement adjustment component has a first adjustment state and a second adjustment state. In the first adjustment state, the beam emitted from the first linear structured light source generates a first emitted beam after passing through the beam displacement adjustment component. In the second adjustment state, the beam emitted from the first linear structured light source generates a second emitted beam after passing through the beam displacement adjustment component. The emission directions of the first emitted beam and the second emitted beam are parallel and partially coincident.
[0007] In some alternative embodiments, the beam displacement adjustment assembly includes a rotation drive and a first planar lens. The first planar lens is connected to the rotation axis of the rotation drive, and the first planar lens has a first position corresponding to the incident angle of a first adjustment state and a second position corresponding to the incident angle of a second adjustment state.
[0008] In some alternative embodiments, the beam displacement adjustment assembly includes a first driving device, and a second planar lens and a third planar lens driven by the first driving device, the second planar lens and the third planar lens having different tilt angles. In a first adjustment state, the first driving device causes the beam emitted from the line structure light source to enter the second planar lens, and in a second adjustment state, the first driving device causes the beam emitted from the line structure light source to enter the third planar lens.
[0009] In some alternative embodiments, the beam displacement adjustment assembly includes a second driving device, a first prism, and a second prism. The first prism and / or the second prism are driven by the second driving device. Both the first prism and the second prism are located in the output optical path of the first linear structure light source. The first prism and the second prism deflect the input beam in opposite directions and with the same degree of deflection. In a first adjustment state, the second driving device sets the first prism and the second prism at a first distance. In a second adjustment state, the second driving device sets the first prism and the second prism at a second distance. The first distance and the second distance are not equal.
[0010] In some alternative implementations, the beam projection module includes: The second structured light source has its beam output end facing the beam angle adjustment component. The third-line structured light source has its beam output end facing the beam angle adjustment component, and its output wavelength is different from that of the second-line structured light source. A beam angle adjustment component is disposed on the common output optical path of the second and third line structured light sources. It is used to adjust the angle of the beams output by the second and / or third line structured light sources. The beam emitted from the second line structured light source generates a first emitted beam after passing through the beam angle adjustment component. The beam emitted from the third line structured light source generates a second emitted beam after passing through the beam angle adjustment component. The emission directions of the first and second emitted beams are parallel and partially coincident.
[0011] In some alternative embodiments, the beam angle adjustment component includes a dichroic mirror, wherein the wavelength of the beam emitted from the second linear structured light source corresponds to the transmission range of the dichroic mirror, the beam emitted from the second linear structured light source illuminates a first side of the dichroic mirror and is transmitted to obtain a first emitted beam, and the wavelength of the beam emitted from the third linear structured light source corresponds to the reflection range of the dichroic mirror, the beam emitted from the second linear structured light source illuminates a second side of the dichroic mirror and is reflected to obtain a second emitted beam.
[0012] In some optional embodiments, the beam angle adjustment component includes a third prism and a fourth prism. The second and third line structured light sources are both disposed on the beam incident side of the third prism, and the fourth prism is disposed on the beam exit side of the third prism. The third and fourth prisms are disposed separately. The beam output by the second line structured light source is parallel to the beam output by the third line structured light source. After being refracted by the third and fourth prisms in sequence, the first and second outgoing beams are obtained respectively.
[0013] In some optional embodiments, the beam angle adjustment component includes a prism assembly with intersecting first and second beam splitters. The wavelength of the beam emitted from the second linear structured light source corresponds to the transmission range of the first beam splitter and the reflection range of the second beam splitter. The wavelength of the beam emitted from the third linear structured light source corresponds to the reflection range of the first beam splitter and the transmission range of the second beam splitter. The second and third linear structured light sources output beams from opposite sides of the prism assembly. The beam output from the second linear structured light source is transmitted through the first beam splitter and reflected by the second beam splitter to obtain a first emitted beam. The beam output from the third linear structured light source is transmitted through the second beam splitter and reflected by the first beam splitter to obtain a second emitted beam.
[0014] In a second aspect, the present invention provides a structured light-based 3D measurement method, applied to a structured light-based 3D measurement system as described in any of the first aspects of the present invention, the method comprising: Acquire a first image including a first light spot and a second image including a second light spot, wherein the first light spot and the second light spot partially overlap on the object being measured; A third image is constructed based on the ratio of the gray values of pixels in the first image to the gray values of corresponding pixels in the second image. 3D measurement of the object under test is performed based on the third image.
[0015] In some alternative implementations, 3D measurement of the object under test is performed based on a third image, including: Extract pixels from the third image whose grayscale value equals a preset value; A structured light trajectory map is constructed based on the extracted pixels; The structured light trajectory map is processed to obtain the 3D point cloud of the object under test.
[0016] In some alternative implementations, a structured light trajectory map is constructed based on the extracted pixels, including: The extracted pixels are used as feature points on the structured light trajectory line, and the feature points are marked in the fourth image. Smooth the feature points in the fourth image; Interpolation is performed on the smoothed feature points to obtain the structured light trajectory map.
[0017] Thirdly, the present invention provides a 3D measurement device based on structured light, comprising: at least one processor; A memory connected to the at least one processor; The memory stores instructions executable by the at least one processor, which executes the instructions stored in the memory to implement the steps of the structured light-based 3D measurement method described in the second aspect.
[0018] Fourthly, the present invention provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implements the steps of the structured light-based 3D measurement method described in the second aspect.
[0019] As can be seen from the above technical solutions, the present invention has the following advantages: This invention provides a structured light-based 3D measurement system. A beam projection module outputs parallel first and second outgoing beams to the object under test, forming partially overlapping first or second light spots on the object. This results in two images, a first image and a second image, corresponding to two different structured light positions. Since the first and second light spots in the first and second images partially overlap, the reflectivity of the object under test at the same position has the same impact on both images. The third image, constructed from the ratio of the grayscale values of corresponding pixels in the first and second images, is unaffected by the object's surface reflectivity. The third image is only related to the initial intensity of the first and second outgoing beams that generated the first and second light spots. Therefore, 3D measurement based on the third image can eliminate the influence of uneven surface reflectivity on the measurement results, obtaining more accurate structured light trajectories and improving measurement accuracy. Attached Figure Description
[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of a 3D measurement system based on structured light in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the distribution of surface reflectance of the object being measured in an embodiment of the present invention; Figure 3 This is a schematic diagram of the intensity function distribution of the first emitted beam in an embodiment of the present invention; Figure 4 This is a schematic diagram of the intensity function distribution of the second emitted beam in an embodiment of the present invention; Figure 5 This is a schematic diagram of the spot brightness function distribution of the first image in an embodiment of the present invention; Figure 6 This is a schematic diagram of the spot brightness function distribution of the second image in an embodiment of the present invention; Figure 7 This is a schematic diagram of the spot brightness function distribution in the third image of this embodiment of the invention; Figure 8 This is a schematic diagram of the structure of the first beam projection module in an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the first beam displacement adjustment component in the first adjustment state in an embodiment of the present invention; Figure 10This is a schematic diagram of the structure of the first beam displacement adjustment component in the second adjustment state in an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of the second beam displacement adjustment component in the first adjustment state in an embodiment of the present invention; Figure 12 This is a schematic diagram of the structure of the second beam displacement adjustment component in the second adjustment state in an embodiment of the present invention; Figure 13 This is a schematic diagram of the third beam displacement adjustment component in the first adjustment state in an embodiment of the present invention; Figure 14 This is a schematic diagram of the third type of beam displacement adjustment component in the second adjustment state in an embodiment of the present invention; Figure 15 This is a schematic diagram of the structure of the second type of beam projection module in an embodiment of the present invention; Figure 16 This is a schematic diagram of the structure of the first beam angle adjustment component in an embodiment of the present invention; Figure 17 This is a schematic diagram of the structure of the second type of beam angle adjustment component in an embodiment of the present invention; Figure 18 This is a schematic diagram of the structure of the third beam angle adjustment component in an embodiment of the present invention; Figure 19 This is a flowchart illustrating the structured light-based 3D measurement method in an embodiment of the present invention.
[0022] Figure label: 100 - Beam projection module; 200 - Image acquisition unit; 300 - Processor; 400 - Object under test; 101 - First line structured light source; 102 - Beam displacement adjustment assembly; 1021 - Rotation drive device; 1022 - First plane lens; 1023 - First drive device; 1024 - Second plane lens; 1025 - Third plane lens; 1026 - Lens support; 1027 - First prism; 1028 - Second prism Mirror; 1029-Second driving device; 103-Second linear structured light source; 104-Third linear structured light source; 105-Beam angle adjustment component; 1051-Dichroic mirror; 1052-Third prism; 1053-Fourth prism; 1054-First beam splitter prism; 1055-Second beam splitter prism; 1056-Third beam splitter prism; 1057-Fourth beam splitter prism; 1058-First beam splitter film; 1059-Second beam splitter film. Detailed Implementation
[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components; or a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms “coincident” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable deviation range, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “equal” includes absolute equality and approximate equality, where an acceptable deviation range for approximate equality may be, for example, a difference between the two equal items less than or equal to 5% of either one. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.
[0025] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0026] Factors affecting the accuracy of structured light feature point recognition mainly include noise and environmental factors. The structured light spot image in the relevant scheme is generated by the reflected light from the laser illuminating the object being measured, as observed by the camera. Therefore, the gray value of each pixel is the product of the laser intensity at that point and the reflectivity of the observed object at that point. If the surface of the observed object has uneven reflectivity due to surface roughness, scratches, dirt, etc., it will directly affect the gray value distribution of the corresponding image, thus interfering with the structured light feature point recognition results.
[0027] Furthermore, in related schemes, the structured light feature points are generally selected from the brightest points on the cross-section of the light spot. Under the same noise background, the greater the numerical gradient between the structured light feature point and its adjacent points, the greater the reliability of accurately identifying that point. Therefore, the structured light spot is finer, resulting in higher actual accuracy. However, due to limitations in device performance, the laser spot generally cannot be made fine enough, thus limiting the measurement accuracy.
[0028] In view of this, embodiments of the present invention provide a 3D measurement system and method based on structured light. On the one hand, it can make the light spot image basically unaffected by the uneven reflectivity of the observed surface, thereby suppressing the influence of environmental factors on measurement accuracy. On the other hand, it can make the same outgoing light beam generate a higher feature point numerical gradient, thereby suppressing the influence of noise factors on measurement accuracy.
[0029] like Figure 1 As shown, this embodiment of the invention provides a 3D measurement system based on structured light, comprising: The beam projection module 100 is used to output a first outgoing beam and a second outgoing beam in parallel directions to the object under test 400. The first outgoing beam and the second outgoing beam form a first light spot and a second light spot on the object under test 400, respectively, and the first light spot and the second light spot partially overlap. The image acquisition device 200 is pointed at the object under test 400 and is used to acquire a first image including a first light spot and a second image including a second light spot. The processor 300 is connected to the image acquisition unit 200, receives the first image and the second image acquired by the image acquisition unit 200, constructs a third image based on the ratio of the gray value of the pixel in the first image to the gray value of the corresponding pixel in the second image, and performs 3D measurement on the object 400 under test based on the third image.
[0030] The first emitted beam and the second emitted beam are both line structured light. The beam projection module 100 can output the first emitted beam and the second emitted beam at different times through a laser, or output the first emitted beam and the second emitted beam through two lasers respectively.
[0031] During 3D measurement, the beam output end of the beam projection module 100 is directed toward the object under test 400. The first and second outgoing beams output by the module are parallel and partially overlap, so that the first and second outgoing beams produce partially overlapping first and second light spots on the object under test 400.
[0032] The overlap ratio of the first light spot and the second light spot can be set according to actual needs. For example, the overlap ratio of the first light spot and the second light spot is 30%, 50% or 70%, etc.
[0033] The image acquisition device 200 includes a camera and a lens, with the lens located at the front of the camera to receive the incident light beam and form an image in the camera.
[0034] When the first emitted light beam and the second emitted light beam produce a first light spot and a second light spot that partially overlap on the object under test 400, the image acquisition unit 200 obtains a first image and a second image based on the light beam reflected from the object under test 400.
[0035] The processor 300 may be a central processing unit, a graphics processing unit, or a combination thereof.
[0036] The processor 300 obtains a first image and a second image through the image acquisition unit 200, and constructs a third image based on the ratio of the gray values of pixels in the first image to the gray values of corresponding pixels in the second image. Since the first and second light spots in the first and second images partially overlap, the reflectivity of the object 400 at the same location has the same impact on both images. Therefore, the third image, constructed using the ratio of the gray values of corresponding pixels in the first and second images, is unaffected by the surface reflectivity of the object. Thus, extracting structured light feature points based on the third image and performing 3D measurements on the object 400 eliminates the influence of uneven surface reflectivity on the measurement results.
[0037] Specifically, because the plane of the measured object 400 is not ideal, its surface reflectivity is as follows: Figure 2 As shown, the horizontal axis represents location, and the vertical axis represents reflectance value. According to... Figure 2 The reflectivity of the object being measured 400 is irregular, with different reflectivities at different locations. The surface reflectivity function of the object being measured 400 is denoted as R(x).
[0038] The intensity functions of the first and second emitted beams output by the beam projection module 100 are generally Gaussian distributions. Figure 3 and Figure 4 These are schematic diagrams showing the intensity distribution of the first and second emitted beams, respectively. The horizontal axis represents position, and the vertical axis represents intensity. The intensity distribution functions corresponding to the first and second emitted beams at two different positions are denoted as L1=g1(x) and L2=g2(x), respectively, where the independent variable x is the value of the horizontal axis.
[0039] The first and second images generated by the image acquisition unit 200 are generated based on the brightness functions of the observed first and second light spots. The brightness functions are the light intensity distribution functions of the first and second outgoing beams multiplied by the surface reflectivity function of the corresponding plane to be measured. Figure 5 and Figure 6These are schematic diagrams showing the distribution of the brightness functions of light spots in the first and second images, respectively. The brightness functions received by the image acquisition unit 200 are R(x)×g1(x) and R(x)×g2(x), respectively. Dividing these two brightness functions, we get (R(x)×g1(x)) / (R(x)×g2(x)) = g1(x) / g2(x). It can be seen that the ratio of the brightness functions of the two light spots can eliminate the random influence of the reflectivity function of the irregular surface of the plane under test. Therefore, in this embodiment of the invention, the gray value of each pixel in the first image is divided by the gray value of the pixel at the same position in the second image, and this ratio is used to construct a third image, that is, the first image is divided by the second image to obtain the third image, and then 3D measurement is performed based on the third image. Figure 7 The third image is a schematic diagram of the light spot brightness function distribution. It is only related to the light field distribution of the first and second outgoing beams and is not affected by the non-uniformity of the surface reflectivity of the object under test 400. Therefore, based on the third image, accurate feature points can be extracted to obtain more accurate structured light trajectory lines and eliminate the influence of the non-uniformity of the surface reflectivity of the object under test 400 on the measurement results.
[0040] Furthermore, according to Figure 7 As can be seen, the brightness function distribution of the spot in the third image has a large numerical gradient, which can more accurately identify feature points. Therefore, the embodiments of the present invention can generate a higher numerical gradient of feature points for the same outgoing beam, thereby suppressing the influence of noise factors on measurement accuracy.
[0041] An embodiment of the present invention provides a structured light-based 3D measurement system. A beam projection module 100 outputs a first and a second beam in parallel directions to a test object 400, forming partially overlapping first or second light spots on the test object 400. This acquires two images, a first image and a second image, corresponding to two different structured light positions. Since the first and second light spots in the first and second images partially overlap, the reflectivity of the test object 400 at the same position has the same influence on the first and second images. The third image, constructed by the ratio of the grayscale values of corresponding pixels in the first and second images, is unaffected by the surface reflectivity of the object. The third image is only related to the initial intensity of the first and second beams that generated the first and second light spots. Therefore, 3D measurement of the test object 400 based on the third image can eliminate the influence of uneven surface reflectivity on the measurement results, obtaining a more accurate structured light trajectory and improving measurement accuracy.
[0042] In some embodiments, such as Figure 8 As shown, the beam projection module 100 includes: The first line structured light source 101 has its beam output end facing the beam displacement adjustment component 102; A beam displacement adjustment component 102 is disposed in the output optical path of the first linear structured light source 101 and located between the first linear structured light source 101 and the object under test 400. The beam displacement adjustment component 102 has a first adjustment state and a second adjustment state. In the first adjustment state, the beam emitted from the first linear structured light source 101 generates a first emitted beam after passing through the beam displacement adjustment component 102. In the second adjustment state, the beam emitted from the first linear structured light source 101 generates a second emitted beam after passing through the beam displacement adjustment component 102. The emission directions of the first emitted beam and the second emitted beam are parallel and partially coincident.
[0043] Specifically, the first line structured light source 101 uses a line structured light laser to output line structured light.
[0044] The first line structured light source 101 outputs line structured light to the beam displacement adjustment component 102. The line structured light is displaced by the beam displacement adjustment component 102, causing the position of the emitted beam to shift to a certain extent.
[0045] In the first and second adjustment states, the first and second emitted beams have different degrees and / or directions of deflection, thus satisfying the condition that the two beams are parallel and partially overlap. For example, the first emitted beam maintains its emission direction and deflects upward, while the second emitted laser maintains its emission direction and deflects downward; the degree of deflection of the first and second emitted beams can be the same or different. Alternatively, the first emitted beam maintains its emission direction and deflects upward, while the second emitted laser maintains its emission direction and deflects downward, but the degree of deflection of the first emitted beam is greater than that of the second emitted beam.
[0046] It should be understood that laser beams are not perfectly parallel; every laser has a focal point, which is the narrowest point of the laser beam. Laser line structured light 3D measurement scenarios can only utilize the laser focal point and a certain distance in front of and behind it. The thickness of the laser beam must be within the maximum thickness required by relevant technical specifications; exceeding this will affect the final specifications. Therefore, each laser structured light beam can only utilize a finite length. Thus, keeping the two line structured light beams—the first and second outgoing beams—parallel is crucial to maintaining their effective usable length; otherwise, the usable length will be reduced, thus affecting the effective measurement depth.
[0047] In this embodiment of the invention, the beam offset is adjusted by the beam displacement adjustment component 102 to obtain parallel and partially overlapping first and second outgoing beams. Only one line structured light source is needed to obtain the partially overlapping first and second light spots. The required number of components is small, and the degree of overlap between the two outgoing beams can be flexibly adjusted.
[0048] In some embodiments, the beam displacement adjustment assembly 102 includes a rotation drive device 1021 and a first planar lens 1022. The first planar lens 1022 is connected to the rotation axis of the rotation drive device 1021. The first planar lens 1022 is provided with a first position corresponding to the incident angle of a first adjustment state and a second position corresponding to the incident angle of a second adjustment state.
[0049] Specifically, the rotary drive device 1021 may be a drive device such as a servo motor or a DD motor.
[0050] The material of the first planar lens 1022 can be glass, crystal, or plastic, etc.
[0051] The first planar lens 1022 is mounted on the rotary drive device 1021, and the rotation axis of the rotary drive device 1021 is parallel to the plane where the first planar lens 1022 is located. The rotary drive device 1021 drives the first planar lens 1022 to rotate, moving it to a first position and a second position, while ensuring that the beam of the incident beam displacement adjustment component 102 can pass through the first planar lens 1022 at any angle and exit. By switching the rotation axis angle of the rotary drive device 1021, the exit beam is shifted by different distances relative to the incident beam.
[0052] In this configuration, the first planar lens 1022 has different tilt angles in the first and second positions, resulting in different incident angles of the light beam input from the first linear structured light source 101 relative to the first planar lens 1022. According to the law of refraction, the light beam will undergo different degrees of translation after passing through the first planar lens 1022. Figure 9 and Figure 10 As shown, the optical axis of the incident beam is from left to right. When the first plane lens 1022 is rotated to tilt downward to the left, it corresponds to the first adjustment state and outputs the first outgoing beam, which is deflected downward. When the first plane lens 1022 is rotated to tilt downward to the right, it corresponds to the second adjustment state and outputs the second outgoing beam, which is deflected upward.
[0053] The beam displacement adjustment component 102 in the above scheme has a simple structure, is easy to adjust, and can accurately control the degree of beam offset, which helps to improve the accuracy and efficiency of measurement. It is suitable for scenarios where there is space to install a drive motor or motor.
[0054] In some embodiments, the beam displacement adjustment assembly 102 includes a first driving device 1023, and a second planar lens 1024 and a third planar lens 1025 driven by the first driving device 1023. The second planar lens 1024 and the third planar lens 1025 have different tilt angles. In a first adjustment state, the first driving device 1023 causes the beam emitted from the line structure light source to enter the second planar lens 1024. In a second adjustment state, the first driving device 1023 causes the beam emitted from the line structure light source to enter the third planar lens 1025.
[0055] Specifically, the first driving device 1023 is a linear driving mechanism, such as a linear motor or cylinder.
[0056] Both the second plane lens 1024 and the third plane lens 1025 are made of flat glass plates.
[0057] The second plane lens 1024 and the third plane lens 1025 have different tilt angles, and their included angle can be set according to the actual situation. For example, the second plane lens 1024 and the third plane lens 1025 can be 60°, 90°, 120°, etc., so that the incident beam will be deflected to different degrees after passing through the second plane lens 1024 or the third plane lens 1025.
[0058] In one example, the second planar lens 1024 and the third planar lens 1025 are mounted at the upper and lower parts of the lens holder 1026 at angles tilted downwards to the left and downwards to the right, respectively. The lens holder 1026 is mounted on the first driving device 1023, which can drive the lens holder 1026 to two different positions, so that the incident beam of the incident beam displacement adjustment assembly 102 exits after passing through the second planar lens 1024 or the third planar lens 1025 on the lens holder 1026. Figure 11 As shown, when the first driving device 1023 drives the lens holder 1026 to move upward, and the incident light beam exits through the third planar lens 1025, the exiting light beam is deflected upward, corresponding to the first adjustment state. Figure 12 As shown, when the first driving device 1023 drives the lens holder 1026 to move downward, the incident beam exits through the second planar lens 1024 and the exit beam deflects downward, corresponding to the second adjustment state.
[0059] By switching the tilt angles of the second plane lens 1024 and the third plane lens 1025 on the lens holder 1026, the outgoing beam is shifted by different distances relative to the incoming beam.
[0060] The beam displacement adjustment component 102 in the above scheme concentrates the optical components in a long and narrow vertical installation space, which has the advantage of a compact horizontal structure and is suitable for scenarios that can provide a long and narrow vertical installation space.
[0061] In some embodiments, the beam displacement adjustment assembly 102 includes a second driving device 1029, a first prism 1027, and a second prism 1028. The first prism 1027 and / or the second prism 1028 are driven by the second driving device 1029. The first prism 1027 and the second prism 1028 are both located in the output optical path of the first linear structure light source. The first prism 1027 and the second prism 1028 deflect the input beam in opposite directions and with the same degree of deflection. In a first adjustment state, the second driving device 1029 sets the first prism 1027 and the second prism 1028 at a first distance. In a second adjustment state, the second driving device 1029 sets the first prism 1027 and the second prism 1028 at a second distance. The first distance and the second distance are not equal.
[0062] Specifically, the second driving device 1029 employs a linear driving mechanism, wherein the second driving device 1029 includes one or two linear driving mechanisms. When the second driving device 1029 includes one linear driving mechanism, the linear driving mechanism can drive the first prism 1027 or the second prism 1028 to move, thereby adjusting the distance between the first prism 1027 and the second prism 1028. When the second driving device 1029 includes two linear driving mechanisms, the two linear driving mechanisms respectively drive the first prism 1027 and the second prism 1028 to move, thereby adjusting the distance between the first prism 1027 and the second prism 1028.
[0063] The first prism 1027 and the second prism 1028 deflect the input beam in opposite directions and with the same degree of deflection. For example, the first prism 1027 and the second prism 1028 are made of the same medium material, and the incident surface of the first prism 1027 is parallel to the exit surface of the second prism 1028, and the exit surface of the first prism 1027 is parallel to the incident surface of the second prism 1028. In this way, the incident beam can maintain its direction after being refracted by the first prism 1027 and the second prism 1028, ensuring that the exit beam is parallel.
[0064] In one example, the first prism 1027 and the second prism 1028 are mounted from left to right on the optical axis of the incident beam, as shown below. Figure 13 As shown, when the second driving device 1029 drives the second prism 1028 to move to the left, reducing the distance between the first prism 1027 and the second prism 1028, corresponding to the first adjustment state, since the distance between the first prism 1027 and the second prism 1028 is small, the downward deflection of the first emitted beam is small. Figure 14As shown, when the second driving device 1029 drives the second prism 1028 to move to the right, increasing the distance between the first prism 1027 and the second prism 1028, corresponding to the second adjustment state, since the distance between the first prism 1027 and the second prism 1028 increases, the degree of downward offset of the first emitted beam increases, thereby obtaining a parallel and partially overlapping first emitted beam and second emitted beam.
[0065] By adjusting the distance between the first prism 1027 and the second prism 1028, the outgoing beam is shifted by different distances relative to the incident beam.
[0066] The beam displacement adjustment component 102 in the above scheme concentrates the optical components in a horizontally narrow installation space, which has the advantage of a vertically compact structure and is suitable for scenarios that can provide a horizontally narrow installation space.
[0067] In some embodiments, such as Figure 15 As shown, the beam projection module 100 includes: The second structured light source 103 has its beam output end facing the beam angle adjustment component 105; The third line structured light source 104 has its beam output end facing the beam angle adjustment component 105, and the output wavelength of the third line structured light source 104 is different from the output wavelength of the second line structured light source 103. A beam angle adjustment component 105 is disposed on the common output optical path of the second line structured light source 103 and the third line structured light source 104. It is used to adjust the angle of the beam output by the second line structured light source 103 and / or the third line structured light source 104. The beam emitted from the second line structured light source 103 generates a first emitted beam after passing through the beam angle adjustment component 105. The beam emitted from the third line structured light source 104 generates a second emitted beam after passing through the beam angle adjustment component 105. The emission directions of the first emitted beam and the second emitted beam are parallel and partially coincident.
[0068] Specifically, both the second line structured light source 103 and the third line structured light source 104 employ line structured light lasers to output line structured light. The output wavelength of the third line structured light source 104 differs from that of the second line structured light source 103. The beam angle adjustment component 105 exhibits different reflection or transmission effects for beams of different wavelengths, enabling the beam angle adjustment component 105 to adjust the beams output by the second line structured light source 103 and the third line structured light source 104 at different angles. This results in the first emitted beam and the second emitted beam having parallel and partially overlapping emission directions.
[0069] The beam angle adjustment component 105 can adjust the angle of the beam output by the second line structured light source 103 or the third line structured light source 104, or it can adjust the angle of the beam output by both.
[0070] This invention utilizes two line structured light sources with different wavelengths and a beam angle adjustment component 105 to generate a first and a second outgoing beam that are parallel and partially overlapped by adjusting the beam angle. Since the two beams have different wavelengths, their angles can be easily adjusted. Furthermore, the two line structured light sources can simultaneously illuminate the object 400 under test for imaging. Subsequently, the first and second images can be extracted from the images based on the color channels corresponding to the two wavelengths, thereby improving measurement efficiency.
[0071] In some embodiments, such as Figure 16 As shown, the beam angle adjustment component 105 includes a dichroic mirror 1051. The wavelength of the beam emitted by the second linear structured light source 103 corresponds to the transmission range of the dichroic mirror 1051. The beam emitted by the second linear structured light source 103 illuminates the first side of the dichroic mirror 1051 and is transmitted to obtain a first emitted beam. The wavelength of the beam emitted by the third linear structured light source 104 corresponds to the reflection range of the dichroic mirror 1051. The beam emitted by the second linear structured light source 103 illuminates the second side of the dichroic mirror 1051 and is reflected to obtain a second emitted beam.
[0072] Specifically, the dichroic mirror 1051 is an optical lens with different transmission and reflection characteristics for light of different wavelengths. It can transmit light with wavelengths within the transmission range and reflect light with wavelengths within the reflection range.
[0073] The angle between the beam output by the second linear structured light source 103 and the dichroic mirror 1051 is the same as the angle between the beam output by the third linear structured light source 104 and the dichroic mirror 1051, so that the directions of the first emitted beam obtained by transmission and the second emitted beam obtained by reflection are the same. By adjusting the positions of the second linear structured light source 103 and the third linear structured light source 104, the first emitted beam and the second emitted beam can be partially overlapped.
[0074] In one example, the dichroic mirror 1051 is tilted at 45°, the second linear structured light source 103 is located on the left side of the dichroic mirror 1051 and outputs the incident beam a from left to right, and the third linear structured light source 104 is located on the upper side of the dichroic mirror 1051 and outputs the incident beam b from top to bottom. The incident beam a is transmitted as the first outgoing beam, and the incident beam b is reflected as the second outgoing beam. The first outgoing beam and the second outgoing beam are parallel and partially overlap.
[0075] The beam angle adjustment component 105 in the above scheme uses a dichroic mirror 1051, which utilizes its transmission and reflection characteristics for beams of different wavelengths to achieve beam separation and merging. It requires fewer components and can accurately control the direction and angle of the beam, but requires a large space to set up the second line structured light source 103 and the third line structured light source 104.
[0076] In some embodiments, such as Figure 17 As shown, the beam angle adjustment component 105 includes a third prism 1052 and a fourth prism 1053. The second linear structured light source 103 and the third linear structured light source 104 are both disposed on the beam incident side of the third prism 1052, and the fourth prism 1053 is disposed on the beam exit side of the third prism 1052. The third prism 1052 and the fourth prism 1053 are disposed separately. The beam output by the second linear structured light source 103 is parallel to the beam output by the third linear structured light source 104. After being refracted by the third prism 1052 and the fourth prism 1053 in sequence, the first exit beam and the second exit beam are obtained respectively.
[0077] Specifically, the third prism 1052 and the fourth prism 1053 deflect the input beam in opposite directions and with the same degree of deflection. For example, the third prism 1052 and the fourth prism 1053 are made of the same medium material, and the incident surface of the third prism 1052 is parallel to the exit surface of the fourth prism 1053, while the exit surface of the third prism 1052 is parallel to the incident surface of the fourth prism 1053. In this way, the incident beam can maintain its direction after being refracted by the third prism 1052 and the fourth prism 1053, ensuring that the exit beam is parallel.
[0078] In one example, the third prism 1052 is positioned to the left of the fourth prism 1053. The second linear structured light source 103 and the third linear structured light source 104 are both positioned to the left of the third prism 1052, and output parallel incident beams a and b, respectively. Due to the different wavelengths of the two beams, their propagation directions will be deflected to different degrees after passing through the third prism 1052. As they gradually approach each other, the two laser beams illuminate the fourth prism 1053, further deflecting their propagation directions and forming two parallel and partially overlapping outgoing laser beams, namely the first outgoing beam and the second outgoing beam.
[0079] The positions of the second line structured light source 103 and the third line structured light source 104 can be adjusted to keep the first emitted beam and the second emitted beam parallel and partially overlapped.
[0080] The beam angle adjustment component 105 in the above solution concentrates the optical components in a horizontally narrow installation space, which has the advantage of a vertically compact structure and is suitable for scenarios that can provide a horizontally narrow installation space.
[0081] In some embodiments, such as Figure 18 As shown, the beam angle adjustment component 105 includes a prism assembly. The prism assembly is provided with an intersecting first beam splitter 1058 and a second beam splitter 1059. The wavelength of the beam emitted by the second linear structured light source 103 corresponds to the transmission range of the first beam splitter 1058 and the reflection range of the second beam splitter 1059. The wavelength of the beam emitted by the third linear structured light source 104 corresponds to the reflection range of the first beam splitter 1058 and the transmission range of the second beam splitter 1059. The second linear structured light source 103 and the third linear structured light source 104 output beams relative to each other on both sides of the prism assembly. The beam output by the second linear structured light source 103 is transmitted through the first beam splitter 1058 and reflected by the second beam splitter 1059 to obtain the first emitted beam. The beam output by the third linear structured light source 104 is transmitted through the second beam splitter 1059 and reflected by the first beam splitter 1058 to obtain the second emitted beam.
[0082] Specifically, the prism assembly includes several beam splitters. When the beams output by the second linear structured light source 103 and the third linear structured light source 104 enter the prism assembly from two directions respectively, due to the different wavelengths, the first beam splitter 1058 and the second beam splitter 1059 of the prism assembly transmit or reflect the two beams respectively, changing the propagation direction of the two beams, thereby obtaining a parallel and partially overlapping first and second outgoing beams.
[0083] The first beam splitter 1058 and the second beam splitter 1059 are obtained by coating the surface of the beam splitter prism, which reflects light beams of a specific wavelength and transmits light of another wavelength.
[0084] In one example, the prism assembly includes a first beam splitter 1054, a second beam splitter 1055, a third beam splitter 1056, and a fourth beam splitter 1057. The cross-sections of the four beam splitters are all isosceles triangles, and the four beam splitters are joined together to form a rectangular structure. A first beam splitter 1058 and a second beam splitter 1059 are located on opposite diagonals of this rectangular structure. A second linear structured light source 103 and a third linear structured light source 104 output beams from opposite sides of the prism assembly. The incident beam a from the second linear structured light source 103, after entering the prism assembly, passes through the first beam splitter 1058 and is reflected at the second beam splitter 1059. Similarly, the incident beam b from the third linear structured light source 104, after entering the prism assembly, passes through the second beam splitter 1059 and is reflected at the first beam splitter 1058. Finally, after each incident beam a and incident beam b undergoes a 90° optical path bend, they merge into two parallel and partially overlapping outgoing beams, namely the first outgoing beam and the second outgoing beam.
[0085] By adjusting the positions of the second line structured light source 103 and the third line structured light source 104, the incident beam a and the incident beam b can be merged, so that the first and second outgoing beams remain parallel and partially overlap.
[0086] The beam angle adjustment component 105 in the above solution has a compact overall structure and is suitable for scenarios where a small installation space is available.
[0087] This invention also provides a structured light-based 3D measurement method, applicable to any of the structured light-based 3D measurement systems described in the above embodiments of this invention, such as... Figure 19 As shown, the method includes: Step S101: Acquire a first image including a first light spot and a second image including a second light spot, wherein the first light spot and the second light spot partially overlap on the object under test 400; Step S102: Construct a third image based on the ratio of the gray values of pixels in the first image to the gray values of corresponding pixels in the second image; Step S103: Perform 3D measurement on the object 400 based on the third image.
[0088] Specifically, the first image and the second image are obtained by the image acquisition device 200 in the above embodiment. The acquisition process is as follows: the beam projection module 100 outputs a first emitted beam to the surface of the object under test 400 to form a first light spot, and the image acquisition device 200 captures the first image; the beam projection module 100 is controlled to output a second emitted beam parallel to the first emitted beam to the surface of the object under test 400 to form a second light spot, and the image acquisition device 200 captures the second image.
[0089] When the beam projection module 100 includes two line structured light sources with different output wavelengths, the two line structured light sources can simultaneously output the first and second outgoing beams to illuminate the object under test 400 to obtain an initial image. Subsequently, the first and second images can be extracted from the initial image based on the color channels corresponding to the two wavelengths, thereby improving measurement efficiency.
[0090] The first and second images have the same field of view. Therefore, each pixel in the first image corresponds one-to-one with each pixel in the second image. The first image is divided by the second image, which is the ratio of the gray value of a pixel in the first image to the gray value of the corresponding pixel in the second image. This yields the gray value of the corresponding pixel in the third image. Thus, the third image is constructed based on the gray values of each pixel.
[0091] The grayscale values obtained from the first and second images are actually the product of the laser intensity at that location and the reflectivity of the measured object at that point. When different lasers are used to illuminate the same location and corresponding images are acquired, the two images are divided to obtain the third image. In this process, the variable of reflectivity at that point of the measured object is canceled out, and what is ultimately obtained is only the ratio of the two laser intensities. This ratio is only related to the laser parameters, has significant stability, and is not affected by external environmental factors. Therefore, subsequent 3D measurements of the measured object 400 based on the third image can effectively eliminate the interference of the surface characteristics of the measured object on the image, thereby obtaining more accurate and reliable measurement information.
[0092] In some embodiments, step S103, which involves performing 3D measurement on the object 400 based on the third image, includes: Step S1031: Extract pixels in the third image whose grayscale value is equal to a preset value; Step S1032: Construct a structured light trajectory map based on the extracted pixels; Step S1033: Process the structured light trajectory map to obtain the 3D point cloud of the measured object 400.
[0093] The preset value can be 1, 1.5 or 2, etc. In one example, the preset value is 1.
[0094] Specifically, step S1032 includes: using the extracted pixels as feature points on the structured light trajectory line, marking the feature points in the fourth image; smoothing the feature points in the fourth image; and interpolating the smoothed feature points to obtain the structured light trajectory map.
[0095] In the third image, since the grayscale value is only related to the light field distribution of the output beam of the beam projection module 100 and is not affected by the surface reflectivity of the object under test 400, and the light field distribution of the output beam is generally fixed, each preset value pixel can be used as a feature point on the structured light trajectory line.
[0096] Create a new blank image, namely the fourth image, and mark the pixels at the corresponding positions of the extracted pixels on it as feature points on the structured light trajectory line. Perform Gaussian smoothing on the structured light trajectory line in the fourth image.
[0097] For the smoothed points in the fourth image, third-order spline interpolation is performed to obtain continuous and smooth structured light trajectory lines. This fourth image is then output as the structured light trajectory map.
[0098] After obtaining the structured light trajectory map, the laser triangulation 3D reconstruction algorithm is used, combined with the previously measured device attitude parameters, to process the structured light trajectory map and obtain the 3D point cloud of the measured object, thus realizing 3D measurement.
[0099] The structured light-based 3D measurement method of this invention outputs a first and a second outgoing beam in parallel directions to the object under test 400 through a beam projection module 100, forming a partially overlapping first or second light spot on the object under test 400. This results in the acquisition of two images, a first image and a second image, corresponding to two different structured light positions. Since the first and second light spots in the first and second images partially overlap, the reflectivity of the object under test 400 at the same position has the same influence on the first and second images. The third image, constructed by the ratio of the gray values of corresponding pixels in the first and second images, is not affected by the reflectivity of the object surface. The third image is only related to the initial intensity of the first and second outgoing beams that generated the first and second light spots. Therefore, 3D measurement of the object under test 400 based on the third image can eliminate the influence of uneven surface reflectivity of the object under test 400 on the measurement results, obtain a more accurate structured light trajectory line, and improve measurement accuracy.
[0100] This invention also provides a 3D measurement device based on structured light, comprising: at least one processor; A memory connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, which executes the instructions stored in the memory to implement the steps of the structured light-based 3D measurement method described in any of the above embodiments.
[0101] This invention also provides a computer-readable storage medium storing a computer program / instructions thereon, which, when executed by a processor, implements the steps of the structured light-based 3D measurement method described in any of the above embodiments.
[0102] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0103] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0104] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0105] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0106] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.
[0107] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.
[0108] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media 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 memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.
[0109] While exemplary embodiments and their advantages have been described in detail, those skilled in the art can make various changes, substitutions and modifications to these embodiments without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined herein.
Claims
1. A 3D measurement system based on structured light, characterized in that, include: The beam projection module is used to output a first outgoing beam and a second outgoing beam in parallel directions to the object under test. The first outgoing beam and the second outgoing beam form a first light spot and a second light spot on the object under test, respectively, and the first light spot and the second light spot partially overlap. An image acquisition device, with its shooting direction pointing towards the object under test, is used to acquire a first image including the first light spot and a second image including the second light spot; The processor is connected to the image acquisition unit, receives the first image and the second image acquired by the image acquisition unit, constructs a third image based on the ratio of the gray values of pixels in the first image to the gray values of corresponding pixels in the second image, and performs 3D measurement on the object under test based on the third image.
2. The 3D measurement system based on structured light according to claim 1, characterized in that, The beam projection module includes: The first line of structured light source has its beam output end facing the beam displacement adjustment component. The beam displacement adjustment component is disposed in the output optical path of the first line structured light source and located between the first line structured light source and the object under test. The beam displacement adjustment component has a first adjustment state and a second adjustment state. In the first adjustment state, the beam emitted from the first line structured light source generates a first emitted beam after passing through the beam displacement adjustment component. In the second adjustment state, the beam emitted from the first line structured light source generates a second emitted beam after passing through the beam displacement adjustment component. The emission directions of the first emitted beam and the second emitted beam are parallel and partially coincident.
3. The 3D measurement system based on structured light according to claim 2, characterized in that, The beam displacement adjustment assembly includes a rotation drive device and a first planar lens. The first planar lens is connected to the rotation axis of the rotation drive device. The first planar lens has a first position corresponding to the incident angle of the first adjustment state and a second position corresponding to the incident angle of the second adjustment state. Alternatively, the beam displacement adjustment assembly includes a first driving device, and a second planar lens and a third planar lens driven by the first driving device. The second planar lens and the third planar lens have different tilt angles. In the first adjustment state, the first driving device causes the beam emitted from the line structure light source to enter the second planar lens. In the second adjustment state, the first driving device causes the beam emitted from the line structure light source to enter the third planar lens. Alternatively, the beam displacement adjustment component includes a second driving device, a first prism, and a second prism. The first prism and / or the second prism is driven by the second driving device. Both the first prism and the second prism are located in the output optical path of the first linear structure light source. The first prism and the second prism deflect the input beam in opposite directions and with the same degree of deflection. In the first adjustment state, the second driving device sets the first prism and the second prism at a first distance. In the second adjustment state, the second driving device sets the first prism and the second prism at a second distance. The first distance and the second distance are not equal.
4. The 3D measurement system based on structured light according to claim 1, characterized in that, The beam projection module includes: The second structured light source has its beam output end facing the beam angle adjustment component. The third line structured light source has its beam output end facing the beam angle adjustment component, and the output wavelength of the third line structured light source is different from the output wavelength of the second line structured light source. A beam angle adjustment component is disposed on the common output optical path of the second linear structured light source and the third linear structured light source. It is used to adjust the angle of the beam output by the second linear structured light source and / or the third linear structured light source. The beam emitted from the second linear structured light source generates a first emitted beam after passing through the beam angle adjustment component. The beam emitted from the third linear structured light source generates a second emitted beam after passing through the beam angle adjustment component. The emission directions of the first emitted beam and the second emitted beam are parallel and partially coincident.
5. The 3D measurement system based on structured light according to claim 4, characterized in that, The beam angle adjustment component includes a dichroic mirror. The wavelength of the beam emitted from the second linear structured light source corresponds to the transmission range of the dichroic mirror. The beam emitted from the second linear structured light source illuminates a first side of the dichroic mirror and is transmitted to obtain the first emitted beam. The wavelength of the beam emitted from the third linear structured light source corresponds to the reflection range of the dichroic mirror. The beam emitted from the second linear structured light source illuminates a second side of the dichroic mirror and is reflected to obtain the second emitted beam. Alternatively, the beam angle adjustment component includes a third prism and a fourth prism. The second linear structured light source and the third linear structured light source are both disposed on the beam incident side of the third prism, and the fourth prism is disposed on the beam exit side of the third prism. The third prism and the fourth prism are disposed separately. The beam output by the second linear structured light source is parallel to the beam output by the third linear structured light source. After being refracted by the third prism and the fourth prism in sequence, the first exit beam and the second exit beam are obtained respectively. Alternatively, the beam angle adjustment component includes a prism assembly. The prism assembly has intersecting first and second beam splitters. The wavelength of the beam emitted by the second linear structured light source corresponds to the transmission range of the first beam splitter and the reflection range of the second beam splitter. The wavelength of the beam emitted by the third linear structured light source corresponds to the reflection range of the first beam splitter and the transmission range of the second beam splitter. The second and third linear structured light sources output beams opposite each other on both sides of the prism assembly. The beam output by the second linear structured light source is transmitted through the first beam splitter and reflected by the second beam splitter to obtain the first emitted beam. The beam output by the third linear structured light source is transmitted through the second beam splitter and reflected by the first beam splitter to obtain the second emitted beam.
6. A 3D measurement method based on structured light, characterized in that, Applied to the structured light-based 3D measurement system as described in any one of claims 1 to 5, the method comprises: Acquire a first image including a first light spot and a second image including a second light spot, wherein the first light spot and the second light spot partially overlap on the object being measured; A third image is constructed based on the ratio of the gray values of pixels in the first image to the gray values of corresponding pixels in the second image. The object under test is measured in 3D based on the third image.
7. The 3D measurement method based on structured light according to claim 6, characterized in that, 3D measurement of the object under test based on the third image includes: Extract the pixels in the third image whose grayscale value is equal to a preset value; A structured light trajectory map is constructed based on the extracted pixels; The structured light trajectory map is processed to obtain the 3D point cloud of the object under test.
8. The 3D measurement method based on structured light according to claim 7, characterized in that, A structured light trajectory map is constructed based on the extracted pixels, including: The extracted pixels are used as feature points on the structured light trajectory line, and the feature points are marked in the fourth image. The feature points in the fourth image are smoothed. The smoothed feature points are then interpolated to obtain a structured light trajectory map.
9. A 3D measurement device based on structured light, characterized in that, include: At least one processor; A memory connected to the at least one processor; The memory stores instructions executable by the at least one processor, which executes the steps of the structured light-based 3D measurement method according to any one of claims 6 to 8 by executing the instructions stored in the memory.
10. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When executed by a processor, the computer program / instructions implement the steps of the structured light-based 3D measurement method as described in any one of claims 6 to 8.