A 3D measurement system and method based on modulatable structured light

Abstract

The present invention discloses a 3D measurement system and method based on modulated structured light, the system comprising: a workbench, on which a workpiece to be measured is placed; two sets of independently working linear light spot generating devices, used to project two sets of intersecting linear light spots, which form reflected linear light spots after being projected onto the workpiece to be measured; an image acquisition device, which is arranged on the reflected light path of the linear light spots and is used to receive the reflected linear light spots to collect images formed by the reflected linear light spots; a control and calculation device, which is electrically connected to the image acquisition device and the linear light spot generating device, respectively, and is used to control the linear light spot generating device to work, and is used to process the images formed by the reflected linear light spots. The present invention provides a structured light generation scheme that projects linear light spots outward by setting two sets of independently working linear light spot generating devices, which has a wide range of applications and is easy to identify the linear light spots corresponding to the intersection points of the linear light spots, thereby improving the efficiency and accuracy of three-dimensional estimation.

Description

Technical Field

[0001] The present invention relates to the field of 3D measurement technology, and in particular to a 3D measurement system and method based on modulated structured light. Background Art

[0002] The light spot with a specific structure pattern generated by the laser is called structured light, which generally has multiple light spots, multiple rays, or specific images with strong light and dark contrast. Structured light can be divided into modulated structured light and non-modulated structured light according to whether the shape of the pattern projected outward can be changed during use. Modulated structured light can change the shape of structured light according to different applications, which can provide great advantages in 3D measurement accuracy, environmental adaptability, application flexibility, etc. Therefore, the modulated structured light 3D measurement system has important technical value.

[0003] There are three existing ways to generate structured light: diffractive optical element (DOE), digital light processing (DLP), and galvanometer. DLP and galvanometer are two solutions that can support modulated structured light. However, the energy utilization rate of the light source in the DLP solution is still insufficient, which limits the brightness. High brightness requires greater power consumption, and thus requires cooling components. The entire component is large in size, which limits its scope of application. The galvanometer solution is difficult to identify the corresponding light spot, which leads to confusion in three-dimensional estimation.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a 3D measurement system and method based on modulated structured light to solve the problem of small application range in the generation method of structured light and difficulty in identifying the corresponding light spot, which causes confusion in three-dimensional estimation.

[0006] The technical solution of the present invention is as follows:

[0007] A 3D measurement system based on modulated structured light, the system comprising:

[0008] A workbench, where the workpiece to be measured is placed;

[0009] Two sets of independently working linear light spot generating devices are used to project two sets of intersecting linear light spots, and the two sets of intersecting linear light spots are projected onto the workpiece to be measured to form reflected linear light spots;

[0010] An image acquisition device, arranged on the reflected light path of the linear light spot and used to receive the reflected linear light spot to acquire an image formed by the reflected linear light spot;

[0011] The control computing device is electrically connected to the image acquisition device and the linear light spot generating device respectively, and is used to control the linear light spot generating device to work, and is used to process the image formed by the reflected linear light spot.

[0012] According to a further configuration of the present invention, the linear light spot generating device comprises:

[0013] A laser for emitting a laser beam;

[0014] A beam expander collimator, arranged on the laser optical path of the laser and used to expand the laser beam emitted by the laser into a laser plane;

[0015] The galvanometer is arranged on the transmission light path of the beam expander and collimator and is used to transform the laser plane into the linear light spot.

[0016] According to a further configuration of the present invention, the galvanometer mirror rotates on a single axis, and the linear light spots reflected by the galvanometer mirror during an interval are a group of parallel linear light spots.

[0017] According to a further configuration of the present invention, the two groups of intersecting linear light spots are distributed vertically or approximately vertically.

[0018] According to a further configuration of the present invention, the two groups of intersecting linear light spots generated by the two groups of independently working linear light spot generating devices include a first linear light spot and a second linear light spot, and the first linear light spot intersects with the second linear light spot to form a plurality of intersections; wherein, if the number of the first linear light spots is m and the number of the second linear light spots is n, then the number of intersections formed by the intersection of the first linear light spot and the second linear light spot is m×n, wherein m is an integer greater than 0, and n is an integer greater than 0.

[0019] According to a further configuration of the present invention, the higher the frequency of the laser switch, the smaller the distribution interval of the linear light spots reflected by the galvanometer in space.

[0020] According to a further configuration of the present invention, the smaller the rotation time difference of the galvanometer, the smaller the overall translation interval of the linear light spot reflected by the galvanometer in space; wherein, the rotation time of the galvanometer is the time difference between the start rotation time of the galvanometer and the start interval switching time of the laser.

[0021] A further configuration of the present invention is to pre-set the switching frequency of the laser and the rotation time difference of the galvanometer.

[0022] Based on the same inventive concept, the present invention also provides a 3D measurement method based on modulated structured light, the method comprising:

[0023] Two sets of independently working linear light spot generating devices project two sets of intersecting linear light spots according to preset parameters; wherein the two sets of intersecting linear light spots are projected onto the workpiece to be measured to form reflected linear light spots;

[0024] An imaging device receives the reflected linear light spot to collect an image formed by the reflected linear light spot;

[0025] The control computing device processes the image acquired by the image acquisition device to obtain the three-dimensional appearance of the workpiece to be measured and outputs it in a point cloud data format.

[0026] In a further configuration of the present invention, the step of controlling the computing device to process the acquired image to obtain the three-dimensional appearance of the workpiece to be measured and outputting it in a point cloud data format specifically includes:

[0027] Obtaining the image coordinates of the intersection point and the spot curve of the two groups of intersecting linear spots;

[0028] Identify the linear light spot corresponding to the intersection point of the two groups of intersecting linear light spots according to the calibration parameters;

[0029] Estimate the three-dimensional coordinates of the intersection point of two sets of intersecting linear light spots;

[0030] Based on the intersection of the two groups of intersecting linear light spots, three-dimensional coordinates of non-intersection points on the light spot curve are estimated;

[0031] Obtain the three-dimensional coordinates of the intersection of two sets of intersecting linear light spots and the three-dimensional coordinates of non-intersection points, and output them in a point cloud data format;

[0032] Repeat the above steps until the three-dimensional appearance of the workpiece to be measured is measured.

[0033] The present invention provides a 3D measurement system and method based on modulated structured light, the system comprising: a workbench, on which a workpiece to be measured is placed; two sets of independently working linear light spot generating devices, used to project two sets of intersecting linear light spots, the two sets of intersecting linear light spots are projected onto the workpiece to be measured to form reflected linear light spots; an image acquisition device, arranged on the reflected light path of the linear light spots and used to receive the reflected linear light spots to acquire images formed by the reflected linear light spots; a control and calculation device, electrically connected to the image acquisition device and the linear light spot generating device, respectively, used to control the linear light spot generating device to work, and used to process the images formed by the reflected linear light spots. The present invention provides a structured light generation scheme that projects linear light spots outward by setting two sets of independently working linear light spot generating devices, which has a wide range of applications and is easy to identify the linear light spots corresponding to the intersections of the linear light spots, thereby improving the efficiency and accuracy of three-dimensional estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary personnel in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0035] Figure 1 It is a schematic diagram of three-dimensional imaging of a planar object by a 3D measurement system based on modulated structured light in the present invention.

[0036] Figure 2 It is a schematic diagram of three-dimensional imaging of curved objects by a 3D measurement system based on modulated structured light in the present invention.

[0037] Figure 3 It is a schematic structural diagram of the linear light spot generating device in the present invention.

[0038] Figure 4 It is a schematic diagram of the linear light spots projected outward by the linear light spot generating device in the present invention at different times.

[0039] Figure 5 It is a schematic diagram of two groups of intersecting linear light spots generated by two groups of linear light spot generating devices in the present invention.

[0040] Figure 6 It is a schematic diagram of the distribution of structured light in multiple frame images in the present invention.

[0041] Figure 7 It is a flow chart of the 3D measurement method based on modulated structured light in the present invention.

[0042] The marks in the attached drawings are: 100, linear light spot generating device; 101, laser; 102, beam expander collimator; 103, galvanometer; 200, image acquisition device; 300, control and calculation device; 400, linear light spot. DETAILED DESCRIPTION

[0043] The inventors found that the light spot with a specific structural pattern generated by the laser is called structured light, which generally has multiple light spots, multiple light rays, or images with strong contrast between light and dark. When the structured light is projected onto the surface of the object, the light spot is deformed on the surface of the object and reflected back to the 3D camera. The camera estimates the coordinates of the surface of the object in three-dimensional space based on the deformed light spot image reflected back. This 3D measurement method has the characteristics of non-contact, high precision, high efficiency, etc., and can overcome environmental interference with high-brightness light spots. Therefore, 3D cameras based on structured light have important application value and are widely used in human-computer interaction, three-dimensional reconstruction, object measurement, face recognition and other fields. Structured light can be divided into modulated structured light and non-modulated structured light according to whether the pattern morphology projected outward can be changed during use. Modulated structured light can change the morphology of structured light according to different applications, which can provide great advantages in 3D measurement accuracy, environmental adaptability, application flexibility, etc. Therefore, the modulated structured light 3D measurement system has important technical value.

[0044] There are three existing ways to generate structured light: diffractive optical element (DOE), digital light processing (DLP), and galvanometer. Among them, DLP and galvanometer are solutions that can support modulated structured light.

[0045] The DOE method is based on the principle of light diffraction. It etches a step-type or continuous relief structure (generally a grating structure) on the substrate to form a type of optical element with coaxial reproduction and extremely high diffraction efficiency. Through different designs, the divergence angle of the light beam and the shape of the light spot are controlled to achieve the function of the light beam forming a specific pattern. Once the diffraction optical element in the DOE solution is installed, it cannot change the shape of the structured light and can only provide a fixed outward projection pattern, so it cannot support the requirements of modulated structured light.

[0046] DLP digital light processing is an imaging technology used in projectors and rear-projection TVs. It first digitally processes the image signal, and then uses the angle change of the microlens array to control the brightness switch to produce the required specific pattern. The DLP solution can support the modulated structured light solution, but its light source energy utilization is still insufficient, which limits the brightness. High brightness requires greater power consumption, and thus requires cooling components. The entire component is large in size, which limits its application range.

[0047] The principle of structured light based on galvanometer is that the light source is periodically switched on and off to form light spots or light beams at time intervals, and then the galvanometer reflects these light spots or light beams into space. Since the galvanometer rotates rapidly when the light source is continuously switched on and off, spaced light spots or light beams are formed in space, forming a specific light spot structure projected outward. Due to the rapid rotation of the galvanometer, it essentially supports modulated structured light. Currently, dual galvanometers are mainly used to form Lissajous trajectories in space. The light source is continuously turned on to form light and dark discontinuities based on the Lissajous trajectory in space, and in theory, any form of structured light can be generated. However, this method has extremely high requirements for the switching frequency of the light source. For example, it needs to be switched on and off hundreds of thousands of times per second to obtain a sufficient number of light spots. Therefore, this method has a small number of 3D measurement points within a fixed time.

[0048] Based on a single galvanometer, a linear light spot is projected outward. By rotating the galvanometer, a group of parallel light spots are formed in space within a period of time. However, the intervals between them cannot be too close, otherwise it will be difficult to distinguish which parallel light spot is in the image, which will cause confusion in three-dimensional estimation. There is also a modulated structured light based on a single galvanometer that projects a linear light spot outward. It requires that the light source should also periodically present different brightness when turned on, so as to form a structured light in the form of moiré fringes. The code corresponding to the moiré fringes is used to identify the angle at which the light is reflected by the galvanometer, so as to realize three-dimensional coordinate estimation. However, linear light spots with lower brightness are easily affected by environmental interference.

[0049] The present invention provides a 3D measurement system and method based on modulated structured light. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] In the embodiments and patent claims, unless otherwise specified, "a", "an" and "the" may refer to a single or a plurality of items.

[0051] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0052] Please also see Figures 1 to 6 The present invention provides a preferred embodiment of a 3D measurement system based on modulated structured light.

[0053] like Figure 1 and Figure 2 As shown, the present invention provides a 3D measurement system based on modulated structured light, which includes a workbench (not shown in the figure), two sets of independently working linear spot generating devices 100, an image acquisition device 200 and a control computing device 300. Specifically, a workpiece to be measured is placed on the workbench, and two groups of linear light spot generating devices 100 work independently and can respectively project a group of linear light spots 400 into the space, and the two groups of linear light spots 400 projected into the space intersect, and the two groups of intersecting linear light spots 400 are projected onto the workpiece to be measured to form reflected linear light spots. The image acquisition device 200 can be a 3D camera, which is arranged on the reflected light path of the linear light spots 400 and can receive the reflected linear light spots to collect images formed by the reflected linear light spots. The control and computing device 300 is electrically connected to the image acquisition device 200 and the linear light spot generating device 100, respectively, and the control and computing device 300 can control the linear light spot generating device 100 to work, and can process the images formed by the reflected linear light spots.

[0054] During the three-dimensional measurement process, two groups of independently working linear light spot generating devices 100 project two groups of intersecting linear light spots 400 into space. The two groups of intersecting linear light spots 400 form a structured light projected onto the surface of the workpiece to be measured. After the structured light is projected onto the workpiece to be measured, it deforms and forms a reflected linear light spot which is reflected into the image acquisition device 200. The image acquisition device 200 estimates the coordinates of the workpiece to be measured in the three-dimensional space based on the deformed light spot image reflected back and forms an image. The control computing device 300 processes the image collected by the image acquisition device 200 to obtain the three-dimensional appearance of the workpiece to be measured. The structured light formed by the two groups of intersecting linear light spots 400 in the present invention is easy to identify the linear light spots 400 corresponding to the intersection of the linear light spots 400, and can quickly perform three-dimensional estimation, thereby improving the efficiency and accuracy of three-dimensional estimation.

[0055] It should be noted that the intersection of the linear light spot 400 is essentially the projection of the intersection line of the two light planes on the imaging plane. In the projective transformation, the projection of the spatial straight line on the plane is still a straight line. Therefore, the present invention can use the projection straight line method to quickly identify the numbers of the two intersecting linear light spots 400 corresponding to the intersection, so as to accurately select the calibration parameters (calibration parameters generally include camera intrinsic parameters, extrinsic parameters, distortion coefficients and light plane coordinates) for three-dimensional estimation, which has high robustness.

[0056] See also Figure 1 , Figure 2 and Figure 3 In a further implementation of an embodiment, the linear light spot generating device 100 includes a laser 101, a beam expander collimator 102 and a galvanometer 103, the laser 101 is used to emit a laser beam, the beam expander collimator 102 is arranged on the laser optical path of the laser 101 and is used to diffuse the laser beam emitted by the laser 101 into a laser plane, the galvanometer 103 is arranged on the transmission optical path of the beam expander collimator 102 and is used to form the laser plane into the linear light spot 400.

[0057] Specifically, the light beam emitted by the laser 101 is diffused into a laser plane after passing through the beam expander collimator 102, and a laser line is generated after being transmitted to the galvanometer 103. With the rotation of the galvanometer 103 and the continuous switching of the laser 101 within a certain period of time, the galvanometer 103 projects a group of parallel laser lines into space. As long as the galvanometer 103 projects a group of parallel laser lines into space within the same exposure time of the 3D camera and can be reflected to the 3D camera, an image of the group of parallel laser lines will be formed on the photosensitive device of the 3D camera, thereby realizing the acquisition of structured light images.

[0058] See also Figure 3 and Figure 4 In a further implementation of an embodiment, the galvanometer 103 rotates uniaxially, and the linear light spots 400 reflected by the galvanometer 103 during the interval time are a group of parallel linear light spots 400 .

[0059] Specifically, because the galvanometer 103 rotates in a single axis, the linear light spots 400 projected outward by the linear light spot generating device 100 at different times are parallel. Figure 4 As shown, in Figure 4 In the figure, t1 to t9 represent different moments. If the camera exposure time completely includes the moments from t1 to t9, the nine laser lines can all be presented on the same frame image, and the nine laser lines are parallel to each other in space.

[0060] See also Figure 3 , Figure 4 and Figure 5 In a further implementation of an embodiment, the two groups of intersecting linear light spots 400 are vertically distributed or approximately vertically distributed.

[0061] In some embodiments, the two groups of intersecting linear light spots 400 generated by the two groups of independently working linear light spot generating devices 100 include a first linear light spot and a second linear light spot, and the first linear light spot and the second linear light spot intersect to form a plurality of intersection points P. For example, the first linear light spot may be a horizontal linear light spot, and the second linear light spot may be a vertical linear light spot. If the number of the first linear light spots is m and the number of the second linear light spots is n, the number of intersection points formed by the intersection of the first linear light spot and the second linear light spot is m×n, where m is an integer greater than 0 and n is an integer greater than 0.

[0062] Specifically, the two groups of linear light spots 400 generated by the two independently working linear light spot generating devices 100 are perpendicular to each other. Figure 2 As shown, the longitudinal linear light spot 400 (vertical linear light spot) projected outward from time t1 to time t9 is generated by one of the groups of linear generating devices, and the transverse linear light spot (horizontal linear light spot) projected outward from time t1 to time t9 is generated by one of the groups of linear generating devices. The two groups of linear light spots 400 form a plurality of evenly distributed intersections. Assuming that the number of horizontal linear light spots is m and the number of vertical linear light spots is n, the number of generated intersections is m×n. Therefore, the control calculation device 300 can identify the corresponding light spots based on the plurality of evenly distributed intersections formed by the two groups of linear light spots 400, or directly estimate the three-dimensional coordinates based on the intersections.

[0063] It can be understood that the two groups of linear light spots 400 generated by the two groups of independently working linear light spot generating devices 100 can intersect with each other, in addition to being vertically distributed, or obliquely intersecting, that is, the two groups of linear light spots 400 can have a certain inclination angle (approximately vertical distribution). The vertical intersection of the two groups of linear light spots 400 makes it easier to identify the linear light spots 400 corresponding to the intersection points.

[0064] In a further implementation of an embodiment, the higher the switching frequency of the laser 101 is, the smaller the distribution interval of the linear light spots 400 reflected by the galvanometer 103 in space is.

[0065] Specifically, the control computing device 300 can control the switching frequency of the laser 101 through the control interface. The higher the frequency, the smaller the spatial distribution interval of the generated linear light spots 400, and vice versa. This is because when the galvanometer 103 rotates at the same speed, the shorter the interval time, the smaller the rotation angle corresponding to two adjacent linear light spots 400, and therefore the closer the distance between the two adjacent linear light spots 400.

[0066] It should be noted that the higher the frequency of the laser 101 switching on, the more and denser the number of linear grid light spots projected by the two sets of independently working linear light spot generating devices 100 per unit time, thereby achieving the adjustment of the three-dimensional measurement density. Of course, the method of adjusting the density of the linear grid light spots by adjusting the frequency of the laser 101 switching on is limited, because too dense grids are prone to interfere with each other and cause erroneous reconstruction.

[0067] See also Figures 3 to 6 In a further implementation of an embodiment, the smaller the rotation time difference of the galvanometer 103 is, the smaller the overall translation interval of the linear light spot 400 reflected by the galvanometer 103 in space in different image frames is. The rotation time of the galvanometer 103 is the time difference between the start rotation time of the galvanometer 103 and the start interval switching time of the laser 101.

[0068] Specifically, the control computing device 300 can adjust the time difference between the start of rotation of the galvanometer 103 and the start of interval switching of the laser 101, so as to form parallel linear light spots with different initial positions, thereby adjusting a group of parallel linear light spots to translate, thereby providing a uniform structured light pattern for multi-frame image acquisition. Figure 6 As shown, Figure 6 What is shown in the figure is the grid of two frame image acquisitions, where the thick solid line is the grid of one frame image acquisition, and the thin solid line is the grid of another frame image acquisition. Obviously, by adjusting the phase difference, the intersection points in multiple frame images can be evenly distributed in space, so that the number of increasing intersection points with equal density can be achieved in the entire space.

[0069] Through the time difference between the start of rotation of the galvanometer 103 and the start of interval switching of the laser 101, the linear grid light spots projected by the two sets of independently working linear light spot generating devices 100 can be translated in two directions (horizontally and vertically). Then, in the first frame, the time difference Δ1 is used to generate the grid W1, and in the second frame, the time difference Δ2 is used to generate the grid W2, and this continues until the time difference Δn in the nth frame generates the grid Wn. Therefore, as long as all the time differences are different, all the grids will not overlap, so that the density of three-dimensional measurement can be linearly increased with the increase of the number of image frames. Compared with the method of adjusting the frequency of the laser 101 switch, the measurement density can be greatly improved by adjusting the rotation time difference of the galvanometer 103. Therefore, the method of adjusting the rotation time difference of the galvanometer 103 is of great value for some high-precision three-dimensional reconstruction tasks that do not require high time.

[0070] It should be noted that if the dual galvanometer 103 is used to generate structured light, each light spot of the dual galvanometer 103 needs to be calibrated. For one frame of image, there are thousands to tens of thousands of points that need to be calibrated, and this calibration process is quite cumbersome. In the present invention, two sets of independently working linear light spot generating devices 100 are used, and the light plane calibration method can be used. Assuming that the number of the first linear light spots is m and the number of the second linear light spots is n, only m+n light planes (corresponding to the number of linear light spots 400) need to be calibrated, and the calibration result can be directly used for the three-dimensional measurement of m×n intersections. Therefore, the method of using two sets of independently working linear light spot generating devices 100 to generate structured light in the present invention has the convenience of calibration.

[0071] It should be noted that before performing 3D measurement, the switching frequency of the laser 101 and the rotation time difference of the galvanometer 103 need to be preset on the control computing device 300 .

[0072] See also Figure 7 Based on the same inventive concept, the present invention also provides a 3D measurement method based on modulated structured light, the method comprising:

[0073] S100, two sets of independently working linear light spot generating devices project two sets of intersecting linear light spots according to preset parameters; wherein the two sets of intersecting linear light spots are projected onto the workpiece to be measured to form reflected linear light spots;

[0074] Specifically, the pre-set parameters include the switching frequency of the laser and the rotation time difference of the galvanometer, wherein the switching frequency of the laser and the rotation time difference of the galvanometer are set by controlling the computing device. After the parameter setting is completed, the linear light spot generating device projects structured light outward according to the set parameters, and the structured light forms a reflected linear light spot after being projected onto the workpiece to be measured.

[0075] S200, an imaging device receives the reflected linear light spot to collect an image formed by the reflected linear light spot;

[0076] The image acquisition device may be a 3D camera, which is disposed on the reflected light path of the linear light spot and is capable of receiving the reflected linear light spot to acquire an image formed by the reflected linear light spot.

[0077] S300, controlling the computing device to process the image acquired by the image acquisition device to obtain the three-dimensional appearance of the workpiece to be measured and output it in a point cloud data format.

[0078] The step of controlling the computing device to process the acquired image to obtain the three-dimensional appearance of the workpiece to be measured and outputting it in a point cloud data format specifically includes:

[0079] S301, obtaining the image coordinates of the intersection point and the spot curve of the two groups of intersecting linear spots;

[0080] S302, identifying the linear light spot corresponding to the intersection of the two groups of intersecting linear light spots according to the calibration parameters;

[0081] S303, estimating the three-dimensional coordinates of the intersection of two groups of intersecting linear light spots;

[0082] S304, estimating the three-dimensional coordinates of non-intersection points on the spot curve based on the intersection points of the two groups of intersecting linear spots;

[0083] S305, obtaining the three-dimensional coordinates of the intersection of the two sets of intersecting linear light spots and the three-dimensional coordinates of the points that are not the intersection, and outputting them in a point cloud data format; wherein the point cloud data format refers to the scanning data being recorded in the form of points, and each point contains three-dimensional coordinates;

[0084] S306, repeating steps S301-S305 until the three-dimensional appearance of the workpiece to be measured is measured.

[0085] In summary, the present invention provides a 3D measurement system and method based on modulated structured light, the system comprising: a workbench, on which a workpiece to be measured is placed; two sets of independently working linear light spot generating devices, used to project two sets of intersecting linear light spots, the two sets of intersecting linear light spots are projected onto the workpiece to be measured to form reflected linear light spots; an image acquisition device, arranged on the reflected light path of the linear light spots and used to receive the reflected linear light spots to acquire images formed by the reflected linear light spots; a control and calculation device, electrically connected to the image acquisition device and the linear light spot generating device, respectively, used to control the linear light spot generating device to work, and used to process the images formed by the reflected linear light spots. The present invention provides a structured light generation scheme that projects linear light spots outward by setting two sets of independently working linear light spot generating devices, which has a wide range of applications and is easy to identify the linear light spots corresponding to the intersections of the linear light spots, thereby improving the efficiency and accuracy of three-dimensional estimation.

[0086] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A 3D measurement system based on modulated structured light, characterized in that: include: A workbench, where the workpiece to be measured is placed; Two sets of independently working linear light spot generating devices are used to project two sets of intersecting linear light spots, which are projected onto the workpiece to be measured to form reflected linear light spots; wherein the intersection of the linear light spots is the projection of the intersection of the two light planes on the imaging plane, and in the projective transformation, the projection of a space straight line on a plane is a straight line; An image acquisition device, arranged on the reflected light path of the linear light spot and used to receive the reflected linear light spot to acquire an image formed by the reflected linear light spot; The control computing device is electrically connected to the image acquisition device and the linear light spot generating device respectively, and is used to control the linear light spot generating device to work, and is used to process the image formed by the reflected linear light spot.

2. The 3D measurement system based on modulated structured light according to claim 1, characterized in that: The linear light spot generating device comprises: A laser for emitting a laser beam; A beam expander collimator, arranged on the laser optical path of the laser and used to expand the laser beam emitted by the laser into a laser plane; The galvanometer is arranged on the transmission light path of the beam expander and collimator and is used to transform the laser plane into the linear light spot.

3. The 3D measurement system based on modulated structured light according to claim 2, characterized in that: The galvanometer mirror rotates on a single axis, and the linear light spots reflected by the galvanometer mirror during the interval time are a group of parallel linear light spots.

4. The 3D measurement system based on modulated structured light according to claim 3, characterized in that: The two groups of intersecting linear light spots are distributed vertically or approximately vertically.

5. The 3D measurement system based on modulated structured light according to claim 4, characterized in that: The two groups of intersecting linear light spots generated by the two groups of independently working linear light spot generating devices include a first linear light spot and a second linear light spot, and the first linear light spot intersects with the second linear light spot to form a plurality of intersections; wherein, if the number of the first linear light spots is m and the number of the second linear light spots is n, then the number of intersections formed by the intersection of the first linear light spot and the second linear light spot is m×n, wherein m is an integer greater than 0, and n is an integer greater than 0.

6. The 3D measurement system based on modulated structured light according to claim 3, characterized in that: The higher the frequency of the laser switch, the smaller the distribution interval of the linear light spots reflected by the galvanometer in space.

7. The 3D measurement system based on modulated structured light according to claim 6, characterized in that: The smaller the rotation time difference of the galvanometer, the smaller the overall translation interval of the linear light spot reflected by the galvanometer in space; wherein, the rotation time of the galvanometer is the time difference between the start rotation time of the galvanometer and the start interval switching time of the laser.

8. The 3D measurement system based on modulated structured light according to claim 7, characterized in that: The switching frequency of the laser and the rotation time difference of the galvanometer are preset.

9. A 3D measurement method based on modulated structured light, characterized in that: include: Two sets of independently working linear light spot generating devices project two sets of intersecting linear light spots according to preset parameters; wherein the two sets of intersecting linear light spots are projected onto the workpiece to be measured to form reflected linear light spots; An image acquisition device receives the reflected linear light spot to acquire an image formed by the reflected linear light spot; The control computing device processes the image acquired by the image acquisition device to obtain the three-dimensional appearance of the workpiece to be measured and outputs it in a point cloud data format.

10. The 3D measurement method based on modulated structured light according to claim 9, characterized in that: The step of controlling the computing device to process the acquired image to obtain the three-dimensional appearance of the workpiece to be measured and outputting it in a point cloud data format specifically includes: Obtaining the image coordinates of the intersection point and the spot curve of the two groups of intersecting linear spots; Identify the linear light spot corresponding to the intersection point of the two groups of intersecting linear light spots according to the calibration parameters; Estimate the three-dimensional coordinates of the intersection point of two sets of intersecting linear light spots; Based on the intersection of the two groups of intersecting linear light spots, three-dimensional coordinates of non-intersection points on the light spot curve are estimated; Obtain the three-dimensional coordinates of the intersection of two sets of intersecting linear light spots and the three-dimensional coordinates of non-intersection points, and output them in a point cloud data format; Repeat the above steps until the three-dimensional appearance of the workpiece to be measured is measured.

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