Laser measurement device and movable platform

Abstract

A laser measurement device (100) and a movable platform (1000). The laser measurement device (100) includes a light emitting module (10), a first optical module (20), a light receiving module (30), and a second optical module (40). The laser pulse of the light emitting module (10) is emitted to a detection object after passing through the first optical module (20), and the laser pulse reflected back by the detection object is incident on the light receiving module (30) after passing through the second optical module (40). The image height of the detection object imaged on the light receiving module (30) has a linear functional relationship with the light receiving half field of view angle of the second optical module (40).

Description

Technical Field

[0001] This application relates to the technical field of laser ranging, and particularly to a laser measurement device and a movable platform. Background Art

[0002] Laser measurement devices, such as lidars, are usually used for ranging. Specifically, the light-emitting module of the laser measurement device emits pulsed laser light towards the detection object, and the light-receiving module of the laser measurement device receives the pulsed laser light reflected back by the detection object to form an image for obtaining the distance. However, for a laser measurement device, when the pixel size of the light-receiving module is determined, different fields of view correspond to different angular resolutions, resulting in a consistency error in the ranging accuracy of each field of view. Summary of the Invention

[0003] Embodiments of this application provide a laser measurement device and a movable platform.

[0004] The laser measurement device according to the embodiments of this application includes a light-emitting module, a first optical module, a light-receiving module, and a second optical module. The light-emitting module is used to emit laser pulses. The first optical module is located on the light-emitting optical path of the light-emitting module and is used to process the laser pulses from the light-emitting module and then emit them to the detection object. The second optical module is located on the light-receiving optical path of the light-receiving module and is used to process the laser pulses reflected back by the detection object and then emit them to the light-receiving module. The light-receiving module is used to convert the received laser pulses reflected back by the detection object into electrical signals, and the image height of the detection object imaged on the light-receiving module has a linear function relationship with the light-receiving half field of view angle of the second optical module.

[0005] The movable platform according to the embodiments of this application includes a movable platform body and a laser measurement device, and the laser measurement device is installed on the movable platform body. The laser measurement device includes a light-emitting module, a first optical module, a light-receiving module, and a second optical module. The light-emitting module is used to emit laser pulses. The first optical module is located on the light-emitting optical path of the light-emitting module and is used to process the laser pulses from the light-emitting module and then emit them to the detection object. The second optical module is located on the light-receiving optical path of the light-receiving module and is used to process the laser pulses reflected back by the detection object and then emit them to the light-receiving module. The light-receiving module is used to convert the received laser pulses reflected back by the detection object into electrical signals, and the image height of the detection object imaged on the light-receiving module has a linear function relationship with the light-receiving half field of view angle of the second optical module.

[0006] The laser measurement device and the movable platform in this application can satisfy that the image height of the detected object imaged on the light receiving module and the light receiving half field of view angle of the second optical module have a linear function relationship. In this way, when the light receiving module receives the pulsed laser reflected by the detected object for imaging to obtain the distance, the angular resolution of each field of view can be unified, which is beneficial to improving the consistency of the three-dimensional imaging of the laser measurement device, and further improving the ranging accuracy of each field of view.

[0007] Additional aspects and advantages of the embodiments of this application will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of this application. Brief Description of the Drawings

[0008] The above and / or additional aspects and advantages of this application will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0009] Figure 1 is a schematic structural diagram of the laser measurement device of some embodiments of this application;

[0010] Figure 2 is a schematic diagram of the imaging principle of the laser measurement device of some embodiments of this application;

[0011] Figure 3 is a schematic diagram of the instantaneous half field of view angle of the second optical module of the laser measurement device of some embodiments of this application;

[0012] Figure 4 is a schematic diagram of the laser pulse incident on the light receiving module when incident on the second optical module at different incident angles of some embodiments of this application;

[0013] Figures 5 to 7 is a schematic structural diagram of the second optical module of some embodiments of this application;

[0014] Figure 8 is a schematic structural diagram of the laser measurement device of some embodiments of this application;

[0015] Figures 9 to 11 is a schematic structural diagram of the first optical module of some embodiments of this application;

[0016] Figure 12 is a schematic diagram of the principle of the signal processing circuit in the laser measurement device of some embodiments of this application for correcting the position coordinates of the detected object;

[0017] Figures 13 to 14 is a schematic structural diagram of the laser measurement device of some embodiments of this application;

[0018] Figure 15 is a schematic structural diagram of the scanning module in the laser measurement device of some embodiments of this application;

[0019] Figure 16 It is a schematic structural diagram of a movable platform according to some embodiments of the present application. Specific embodiments

[0020] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary only for explaining the present application and should not be construed as limiting the present application.

[0021] Please refer to Figure 1 and Figure 2 , the laser measurement device 100 includes a light emitting module 10, a first optical module 20, a light receiving module 30, and a second optical module 40. The light emitting module 10 is used to emit laser pulses; the first optical module 20 is located on the light emitting optical path of the light emitting module 10 and is used to process the laser pulses from the light emitting module 10 and emit them to the detection object; the second optical module 40 is located on the light receiving optical path of the light receiving module 30 and is used to process the laser pulses reflected back by the detection object and emit them to the light receiving module 30; the light receiving module 30 is used to convert the received laser pulses reflected back by the detection object into electrical signals, and the image height y2 of the detection object imaged on the light receiving module 30 has a linear function relationship with the light receiving half field of view angle θ2 of the second optical module 40.

[0022] The laser measurement device 100 in the present application can satisfy that the image height y2 of the detection object imaged on the light receiving module 30 has a linear function relationship with the light receiving half field of view angle θ2 of the second optical module 40. Thus, when the light receiving module 30 receives the pulsed laser reflected back by the detection object to form an image for obtaining the distance, the angular resolution of each field of view can be unified, which is beneficial to improving the consistency of the three-dimensional imaging of the laser measurement device 100 and further improving the ranging accuracy of each field of view.

[0023] The following will be further described with reference to the accompanying drawings.

[0024] Please refer to Figure 1 , the laser measurement device 100 includes a light emitting module 10, a first optical module 20, a light receiving module 30, and a second optical module 40. The first optical module 20 is located on the light emitting optical path of the light emitting module 10, and the second optical module 40 is located on the light receiving optical path of the light receiving module 30. The laser pulses emitted by the light emitting module 10 are emitted to the detection object through the first optical module 20, and the light receiving module 30 receives the laser pulses reflected by the detection object and passing through the second optical module 40.

[0025] Specifically, the light emitting module 10 is configured to emit laser pulses. In some embodiments, the light emitting module 10 may include a laser diode array. For example, in some embodiments, the light emitting module 10 includes a Vertical Cavity Surface Emitting Laser (VCSEL). Since the vertical cavity surface emitting laser is small in size and easy to be integrated into a large area array, using the vertical cavity surface emitting laser as the light source in the light emitting module 10 can reduce the volume of the light emitting module 10, and further reduce the volume of the laser measuring device 100. For another example, in some embodiments, the light emitting module 10 includes an Edge-Emitting Laser (EEL). Specifically, the edge-emitting laser may be a Distributed Feedback Laser (DFB). Using the edge-emitting laser as the light source in the light emitting module 10, on the one hand, the temperature drift of the edge-emitting laser is smaller than that of the VCSEL array. On the other hand, since the edge-emitting laser is a single-point light emitting structure, there is no need to design an array structure, and the manufacturing is simple and the cost is low. Of course, in some embodiments, the light emitting module 10 may include a light emitting diode array, which will not be exemplified one by one here.

[0026] Please refer to Figure 2 , the light receiving module 30 is configured to convert the received laser pulses reflected by the detection object into electrical signals. Exemplarily, the light receiving module 30 may include a photoelectric sensor 31. The photoelectric sensor 31 may include at least one of a Photo-Diode (PD), an Avalanche Photo Diode (APD), a Single-Photon Avalanche Diode (SPAD), a Multi Pixel photon counter (MPPC), or a Silicon photomultiplier (SiPM). In some embodiments, the pixels (not shown in the figure) in the photoelectric sensor 31 may be arranged in a matrix, which is beneficial for the light receiving module 30 to receive the laser pulses reflected by the detection object. Of course, the pixels in the photoelectric sensor 31 may also be arranged in a linear array, which is not limited herein.

[0027] Please refer to Figure 1 and Figure 2, the first optical module 20 is located on the light-emitting optical path of the light-emitting module 10 and is configured to process the laser pulses from the light-emitting module 10 and then emit them to the object to be detected. The second optical module 40 is located on the light-receiving optical path of the light-receiving module 30, and the optical axis of the second optical module 40 is perpendicular to the imaging surface of the photoelectric sensor 31 of the light-receiving module 30. The second optical module 40 is configured to process the laser pulses reflected back by the object to be detected and then emit them to the light-receiving module 30. The laser pulses reflected back by the object to be detected can be imaged on the light-receiving module 30 after passing through the second optical module 40, and the image height y2 of the object to be detected imaged on the light-receiving module 30 has a linear function relationship with the light-receiving half field of view angle θ2 of the second optical module 40.

[0028] Specifically, the effective focal length f2 of the second optical module 40 can be obtained according to the image height y2 of the object to be detected imaged on the light-receiving module 30 and the light-receiving half field of view angle θ2 of the second optical module 40. In some embodiments, the effective focal length f2 of the second optical module 40 is the ratio of the image height y2 of the object to be detected imaged on the light-receiving module 30 to the light-receiving half field of view angle θ of the second optical module 40. For example, the laser measurement module 100 satisfies the following relationship: y2 = f2 × θ2, where: y2 is the image height of the object to be detected imaged on the light-receiving module 30, f2 is the effective focal length of the second optical module 40, and θ2 is the light-receiving half field of view angle of the second optical module 40. Substituting the image height y2 of the object to be detected imaged on the light-receiving module 30 and the light-receiving half field of view angle θ2 of the second optical module 40 into the above formula for calculation, the effective focal length f2 of the second optical module 40 can be obtained.

[0029] It should be noted that in the existing laser measurement device, the following relationship is satisfied: y 现 = 现 × tanθ 现 , where y 现 is the image height of the object to be detected imaged on the light-receiving module in the existing laser measurement device, f 现 is the effective focal length of the optical system in the existing laser measurement device, and θ 现 is the light-receiving half field of view angle of the optical system in the existing laser measurement device. That is to say, in the existing laser measurement device, the receiving optical system generally satisfies the point tangent projection imaging relationship. When the photoelectric sensor in the light-receiving module is composed of multiple pixels of the same size, the angular resolution of the target objects at different field of view angle positions is inconsistent on the image plane. However, in the embodiments of the present application, the laser measurement module 100 satisfies the relationship y2 = f2 × θ2. Differentiating both ends of the above formula gives △y2 = f2 × △θ2. It can be understood that when the pixel size of the photoelectric sensor 31 of the receiving module 30 is △y2, each unit pixel corresponds to a unit field of view angle △θ2. Within the effective field of view range, each pixel corresponds to an equal angle, that is, the angular resolution of each field of view is unified.

[0030] In addition, when the laser measurement device 100 in the embodiments of the present application has the same image height and the same focal length as the existing laser measurement device, that is, y2 = y 现 and f2 = f 现 at this time, the half field of view angle θ2 of the second optical module 40 in the embodiments of the present application is greater than the light receiving half field of view angle θ of the optical system in the existing laser measurement device 现 . That is to say, compared with the existing laser measurement device, the laser measurement device 100 in the embodiments of the present application can obtain a larger field of view angle under the condition of the same image height and the same focal length, so as to expand the detection range.

[0031] Please refer to Figure 2 and Figure 3 together. In some embodiments, after determining the radius y0 of the photoelectric sensor array in the light receiving module 30 and the maximum instantaneous half field of view angle θ0 that the laser measurement module 100 needs to reach, the effective focal length f2 of the second optical module 40 is obtained according to the maximum radius y0 of the photoelectric sensor 31 in the light receiving module 30 and the maximum instantaneous half field of view angle θ0 of the laser measurement device 100. In some embodiments, the effective focal length f2 of the second optical module 40 is equal to the ratio of the maximum radius y0 of the photoelectric sensor 31 in the light receiving module 30 to the maximum instantaneous half field of view angle θ0 of the laser measurement device 100. For example, the laser measurement module 100 satisfies the following relational expression: y0 = f2 × θ0, where: y0 is the maximum radius of the photoelectric sensor 31, f2 is the effective focal length of the second optical module 40, and θ0 is the maximum instantaneous half field of view angle of the laser measurement device 100.

[0032] It should be noted that there may be other modules in the laser measurement device 100 that can further expand the field of view of the laser measurement device 100 for receiving laser pulses, such as Figure 3 shown, m1 is the field of view of the second optical module 40 directly receiving laser pulses, and m2 is the field of view of the second optical module 40 receiving laser pulses after being processed by other modules in the laser measurement device 100. For example, assume that the field of view angle of the second optical module 40 that can directly receive laser pulses is 10°, and other modules provided in the laser measurement device 100 can swing the field of view of the received laser pulses up and down by 20°. In this way, the actual field of view angle of the laser measurement device 100 is 50°. When at a certain moment the laser measurement device 100 can obtain the laser pulses reflected by the detection object within 10°, but at different moments it can see the laser pulses reflected by the detection object within a total of 50°. The maximum instantaneous half field of view angle of the laser measurement device 100 refers to the half field of view angle θ0 of the second optical module 40 receiving laser pulses at a certain moment.

[0033] In some embodiments, according to the minimum allowable optical power P received by the light receiving module 30 S , the power P of the laser pulse emitted by the light emitting module 10 T , the scattering cross section σ of the detection object, the area A illuminated by the laser pulse illum , the entrance pupil vignetting coefficient η vig , the preset limit range R of the laser measurement device 100, and the overall transmittance η of the laser measurement device 100 sys obtain the entrance pupil diameter D of the second optical module 40 (as Figure 5 shown). For example, the laser measurement module 100 satisfies the following relational expression: wherein, Ps is the minimum allowable optical power received by the light receiving module 30; P T is the power of the laser pulse emitted by the light emitting module 10; σ is the scattering cross section of the detection object; A illum is the area illuminated by the laser pulse; η vig is the entrance pupil vignetting coefficient; R is the preset limit range of the laser measurement device 100; η svs is the overall transmittance of the laser measurement device 100; D is the entrance pupil diameter of the second optical module 40. After obtaining the minimum allowable optical power Ps received by the light receiving module 30, the power P of the laser pulse emitted by the light emitting module 10 T , the scattering cross section σ of the detection object, the area A illuminated by the laser pulse illum , the entrance pupil vignetting coefficient η vig , the preset limit range R of the laser measurement device 100, and the overall transmittance η of the laser measurement device 100 sys , substitute into the above calculation formula: calculate, and the entrance pupil diameter D of the second optical module 40 can be obtained. It should be noted that the entrance pupil vignetting coefficient is related to the shape of the entrance pupil and whether there is an occlusion at the entrance pupil. In particular, when the entrance pupil of the second optical module 40 is an unobstructed circular pupil, the entrance pupil vignetting coefficient η vig is equal to 0.

[0034] Since the Lagrange invariant J = n × y × u is satisfied in any optical system, where y is the image height, n is the refractive index of the medium, and u is the aperture angle. That is to say, in an optical system, the product of the image height, the refractive index of the medium, and the aperture angle is a constant. And the aperture angle u can be obtained through the calculation formula , where D is the entrance pupil diameter of the second optical module, and f is the focal length of the optical system. Thus the Lagrange invariant It can be understood that when two optical systems are in the same medium and have the same image height and the same Lagrange invariant J, the ratio of the entrance pupil diameter D to the focal length f is a constant value, that is, the entrance pupil diameter D is positively correlated with the focal length f. As described above, the laser measurement module 100 in the embodiments of the present application satisfies the following relationship: y2 = f2×θ2, and the existing laser measurement device satisfies the following relationship: y 现 = f 现 ×tanθ 现 , when the laser measurement device 100 in the embodiments of the present application and the existing laser measurement device have the same image height and the same half field of view angle, that is, y2 = y 现 and θ2 = θ 现 , the effective focal length f2 of the second optical module 40 in the embodiments of the present application is greater than the f of the optical system in the existing laser measurement device 现 . Also, because when two optical systems are in the same medium and have the same image height and the same Lagrange invariant J, the entrance pupil diameter D is positively correlated with the focal length f. Therefore, when the laser measurement device 100 in the embodiments of the present application and the existing laser measurement device are in the same medium and have the same image height, the same half field of view angle and the same Lagrange invariant J, the entrance pupil diameter D of the second optical module 40 in the embodiments of the present application is greater than the entrance pupil diameter D of the optical system in the existing laser measurement device 现 . That is to say, the second optical module 40 in the embodiments of the present application has a larger entrance pupil diameter D, thereby being able to improve the light receiving ability of the laser measurement device 100

[0035] In some embodiments, the effective focal length f2 of the second optical module 40 is obtained according to the distortion amount δy2 of the second optical module 40 and the light receiving half field of view angle θ2 of the second optical module 40. Specifically, there is a difference between the light receiving half field of view angle θ2 of the second optical module 40 and the tangent value tanθ2 of the light receiving half field of view angle of the second optical module 40, and the effective focal length f2 of the second optical module 40 is the ratio of the distortion amount δy2 of the second optical module 40 to the difference. For example, the distortion amount δy2 of the second optical module 40 satisfies the formula: δy2 = f2×(θ2 - tanθ2), where: δy2 is the distortion amount of the second optical module 40, and θ2 is the light receiving half field of view angle of the second optical module 40. After obtaining the distortion amount δy2 of the second optical module 40 and the light receiving half field of view angle θ2 of the second optical module 40 and substituting them into the above formula, the effective focal length f2 of the second optical module 40 can be calculated

[0036] Please refer to Figure 4, in some embodiments, the second optical module 40 can vertically incident the principal ray L of the laser pulse incident on the second optical module 40 at different incident angles α onto the imaging surface of the light receiving module 30. That is to say, after being incident on the second optical module 40 at different incident angles α and being processed by the second optical module 40 (including refraction or diffraction, etc.), its principal ray can be vertically incident on the imaging surface of the light receiving module 30. For example, as Figure 4 shown, for the laser pulse incident on the second optical module 40 at the incident angle α1, after being processed by the second optical module 40, its corresponding principal ray L1 is vertically incident on the imaging surface of the light receiving module 30; for the laser pulse incident along the direction perpendicular to the light receiving surface of the second optical module 40, after being processed by the second optical module 40, its corresponding principal ray L2 is also vertically incident on the imaging surface of the light receiving module 30. Thus, in the embodiment of the present application, the second optical module 40 can make the principal rays L of the laser pulses incident on the second optical module 40 at different incident angles α vertically incident on each pixel of the light receiving module 30, so that each pixel has uniform illuminance, thereby ensuring that the images obtained at various angles have the same brightness, which is beneficial to improving the image quality of the finally obtained images.

[0037] Please refer to Figures 5 to 7 , the second optical module 40 may include one or more lenses 41, and the multiple lenses 41 can be glass lenses or plastic lenses. For example, as Figure 5 shown, the second optical module 40 may include only one lens 41, and the lens 41 can be made of glass or plastic. As Figure 6 and Figure 7 shown, the second optical module 40 may include multiple lenses 41, and the types, materials, and the spacing between two adjacent lenses 41 of the multiple lenses 41 can be exactly the same; or the types, materials, and the spacing between two adjacent lenses 41 of the multiple lenses 41 can be at least partially the same; or the types, materials, and the spacing between two adjacent lenses 41 of the multiple lenses 41 can be completely different, which is not limited herein, and only needs to satisfy that the image height y2 of the detected object imaged on the light receiving module 30 is equal to the effective focal length f2 of the second optical module 40 multiplied by the light receiving half field of view angle θ2 of the second optical module 40. It should be noted that when the second optical module 40 includes multiple lenses 41, the effective focal length f2 of the second optical module 40 refers to the focal length after the combination of the multiple lenses 41.

[0038] In some embodiments, as Figure 8 and Figure 14, the first optical module 20 and the second optical module 40 are the same module, that is, the first optical module 20 and the second optical module 40 share the same set of optical module 401. The optical module 401 can be the same as the second optical module 40 described in any of the above embodiments, and the optical module 401 is located on the light-emitting optical path of the transmitting module 10 and the light-receiving optical path of the light-receiving module 30 at the same time. When the light-emitting module 10 emits a laser pulse, the laser pulse is processed by the optical module 401 and then exits to the detected object; the laser pulse reflected by the detected object is processed by the optical module 401 and then exits to the light-receiving module 30.

[0039] Of course, in some embodiments, the first optical module 20 and the second optical module 40 are two separate modules for transmitting and receiving, such as Figure 1 and Figure 13 shown, that is, the first optical module 20 and the second optical module 40 each use a set of optical modules. The second optical module 40 can be the second optical module 40 described in any of the above embodiments, and the first optical module 20 can be an existing optical system, that is, the height y1 of the light-emitting module and the light-emitting half field of view angle θ1 of the first optical module 20 do not satisfy a linear function relationship. In this way, only the second optical module 40 needs to be improved to achieve the unification of the resolution of each field of view angle, which can reduce the cost compared with improving the first optical module 20 as well.

[0040] In some embodiments, when the first optical module 20 and the second optical module 40 are two separate modules for transmitting and receiving, the second optical module 40 can be the second optical module 40 described in any of the above embodiments, and the height y1 of the light-emitting module 10 and the light-emitting half field of view angle θ1 of the first optical module 20 are in a linear function relationship. Specifically, as Figure 9 shown, the effective focal length f1 of the first optical module 20 is obtained according to the height y1 of the detected object in the light-emitting module 10 and the light-emitting half field of view angle θ1 of the first optical module 20. The laser measurement module 100 satisfies the following relational formula: y1 = f1×θ1, where: y1 is the height of the light-emitting module 10, f1 is the effective focal length of the first optical module 20, and θ1 is the light-emitting half field of view angle of the first optical module 20. After determining the value of the height y1 of the light-emitting and receiving module 10 and the value of the light-emitting half field of view angle θ1 of the first optical module 20, substituting them into the above calculation formula y1 = f1×θ1 for calculation, the effective focal length f1 of the first optical module 20 can be obtained. In this way, the divergence angle of the laser pulse in each direction can be made consistent, which is beneficial to improving the consistency of the three-dimensional imaging of the laser measurement device 100.

[0041] Please refer to Figures 9 to 11 , the first optical module 20 may also include one or more lenses 21, and the multiple lenses 21 can also be glass lenses or plastic lenses. For example, as Figure 9As shown, the first optical module 20 may include only one lens 21, and the lens 21 may be made of glass or plastic; for example Figure 10 and Figure 11 as shown, the first optical module 20 may include a plurality of lenses 21, and the types, materials, and the spacing between two adjacent lenses 21 of the plurality of lenses 21 may be exactly the same; or the types, materials, and the spacing between two adjacent lenses 21 of the plurality of lenses 21 may be at least partially the same; or the types, materials, and the spacing between two adjacent lenses 21 of the plurality of lenses 21 may be completely different, which is not limited herein.

[0042] In some embodiments, the operating wavelengths of the first optical module 20 and the second optical module 40 include at least one of 850 nm, 905 nm, 940 nm, and 1550 nm. The laser pulse wavelength of the light emitting module 10 matches the response spectrum of the light receiving module 30 and also matches the operating wavelength of at least one of the first optical module 20 and the second optical module 40. For example, the operating wavelength of the first optical module 20, the laser pulse wavelength of the light emitting module 10, and the response spectrum of the light receiving module 30 are matched, so that all the laser pulses emitted by the light emitting module 10 can pass through the first optical module 20 and be emitted to the detection object; or, the operating wavelength of the second optical module 40, the laser pulse wavelength of the light emitting module 10, and the response spectrum of the light receiving module 30 are matched, so that the laser pulses emitted by the light emitting module 10 and reflected by the detection object can all pass through the second optical module 40 and enter the light receiving module 30; or, the operating wavelength of the first optical module 20, the operating wavelength of the second optical module 40, the laser pulse wavelength of the light emitting module 10, and the response spectrum of the light receiving module 30 are all matched, so that all the laser pulses emitted by the light emitting module 10 can pass through the first optical module 20 and be emitted to the detection object, and the laser pulses reflected by the detection object can all pass through the second optical module 40 and enter the light receiving module 30, which is beneficial to the three-dimensional imaging of the laser measurement device 100.

[0043] Please refer to Figure 1 , the laser measurement device 100 may further include a driving circuit 50 and a signal processing circuit 60. The driving circuit 50 is electrically connected to the light emitting module 10, and the driving circuit 50 is used to drive the light emitting module 10 to emit light. The signal processing circuit 60 is connected to the light receiving module 30 and is used to process the electrical signal converted by the light receiving module 30 to obtain the three-dimensional information of the detection object.

[0044] In some embodiments, the signal processing circuit 60 is further configured to correct the position coordinates of the detected object in the plane perpendicular to the optical axis according to a preset distortion correction function F(x'). Specifically, the signal processing circuit 60 substitutes the coordinates of the detected object obtained on the light receiving surface of the light receiving module 30 into the distortion correction function F(x') for calculation to obtain the actual position coordinates of this point in the plane perpendicular to the optical axis, thereby correcting the position coordinates of the detected object in the plane perpendicular to the optical axis.

[0045] It should be noted that the preset distortion correction function F(x') is calibrated through a large number of experiments according to the principle of one-to-one correspondence between the object space and the image space before the laser measurement module 100 leaves the factory. Specifically, as Figure 12 shown, multiple objects are calibrated in the object space, and each object has a unique object space coordinate x in the object space. Then, the coordinates of each object on the light receiving surface of the light receiving module 30 are collected and recorded as the image space coordinate x'. Through numerical fitting means such as the least squares method for multiple object space coordinates x and the corresponding image space coordinates x', the mapping relationship between the actual object space coordinate x and the corresponding image space coordinate x' is calibrated, and the mapping function H(x) is obtained according to this mapping relationship, that is, substituting the object space coordinate x into H(x) can obtain the corresponding image space coordinate x'. Since there is a strict one-to-one correspondence between the object space and the image space, that is, the mapping function H(x) is invertible, the inverse mapping function F(x') of the mapping function H(x) can be obtained, that is, substituting the image space coordinate x' into the inverse mapping function F(x') can obtain the corresponding object space coordinate x. In this way, the inverse mapping function F(x') is used as the preset distortion correction function F(x'). When the coordinates of the detected object on the light receiving surface of the light receiving module 30 are substituted into the distortion correction function F(x') for calculation, the actual position coordinates of the detected object in the plane perpendicular to the optical axis can be obtained. For example, as Figure 12 shown, during the use of the laser measurement device 100, an object A1 with an object space coordinate x 3 can be imaged on the light receiving module 30, and the signal processing circuit 60 can obtain the image space coordinate x' of the object A1 on the light receiving surface 3 , where the image space coordinate x' 3 has a mapping relationship H(x) with the object space coordinate x 3 , that is, H(x 3 ) = x' 3 . The signal processing circuit 60 substitutes the image space coordinate x' 3 of its object A1 into the preset distortion correction function F(x') to obtain the corrected coordinate X 3 of the object A1. Since F(x') is the inverse mapping function of H(x), the corrected coordinate X 3 of the object A1 is the same as the object space coordinate x 3They are the same. That is to say, the position coordinates of the detected object in the plane perpendicular to the optical axis obtained after being corrected by the signal processing circuit 60 are the same as the actual position coordinates of the detected object in the object space, thereby improving the measurement accuracy of the laser measurement device 100.

[0046] Please refer to Figure 13 and Figure 14 , in some embodiments, the laser measurement module 100 may further include a scanning module 70. The scanning module 70 is located on the light emitting optical path and the light receiving optical path, and is used to change the laser pulses from the light emitting module 10 to be emitted in different transmission directions, and conduct the laser pulses reflected by the detected object to the light receiving module 30. Specifically, please refer to Figure 15 , the scanning module 70 includes a controller 71, a driver 72 and an optical element 73. The controller 71 is electrically connected to the driver 72, and the driver 72 is used to drive the optical element 73 to move, so as to change the transmission direction of the laser passing through the optical element 73. The optical element 73 may be a lens, a mirror, a prism, a grating, an optical phased array (Optical Phased Array) or any combination of the above optical elements. The driver 72 can drive the optical element 73 to rotate, vibrate, move in a circular motion along a predetermined trajectory or move back and forth along a predetermined trajectory, which is not limited herein. Since the laser measurement module 100 further includes the scanning module 70, the scanning module 70 can further expand the light emitting field of view and the light receiving field of view of the laser measurement device 100, thereby facilitating the expansion of the measurement range of the laser measurement device 100.

[0047] Please refer to Figure 16 , the embodiment of the present application further provides a movable platform 1000, and the movable platform 1000 includes a movable platform body 200 and the laser measurement device 100 of any of the above embodiments. The laser measurement device 100 is installed on the movable platform body 200. The movable platform 1000 may be an unmanned aerial vehicle, an unmanned vehicle, an unmanned ship, a robot, an armored vehicle, etc. One movable platform 1000 may be configured with one or more laser measurement modules 100. The laser measurement module 100 can be used to detect the environment around the movable platform 1000, so that the movable platform 1000 can further perform operations such as obstacle avoidance and trajectory selection according to the surrounding environment. The laser measurement module 100 may be disposed at the front or upper part of the movable platform 1000, and the present application does not limit this.

[0048] The laser measurement device 100 in the movable platform 1000 can satisfy that the image height y2 of the detected object imaged on the light receiving module 30 and the light receiving half field of view angle θ2 of the second optical module 40 have a linear function relationship. Thus, when the light receiving module 30 receives the pulsed laser reflected by the detected object to form an image for obtaining the distance, the angular resolution of each field of view can be unified, which is beneficial to improving the consistency of the three-dimensional imaging of the laser measurement device 100, so that the movable platform 1000 can obtain a more accurate surrounding environment, and further improve the ranging accuracy of each field of view.

[0049] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Any process or method description shown in the flowchart or described in other ways herein can be understood to represent a module, segment or part of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present application includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in the reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art of the embodiments of the present application. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A laser measurement device, characterized in that, it includes a light-emitting module, a first optical module, a light-receiving module, and a second optical module; the light-emitting module is used to emit laser pulses; the first optical module is located on the light-emitting optical path of the light-emitting module and is used to process the laser pulses from the light-emitting module and then emit them to the detection object; the second optical module is located on the light-receiving optical path of the light-receiving module and is used to process the laser pulses reflected back by the detection object and then emit them to the light-receiving module; the light-receiving module is used to convert the received laser pulses reflected back by the detection object into electrical signals, and the image height of the detection object imaged on the light-receiving module has a linear function relationship with the light-receiving half field of view angle of the second optical module.

2. The laser measurement device according to claim 1, characterized in that, the effective focal length of the second optical module is obtained based on the image height of the detection object imaged on the light-receiving module and the light-receiving half field of view angle of the second optical module.

3. The laser measurement device according to claim 2, characterized in that, the light-receiving module includes a photoelectric sensor, and the effective focal length of the second optical module is obtained based on the maximum radius of the photoelectric sensor and the maximum instantaneous half field of view angle of the laser measurement device.

4. The laser measurement device according to claim 1, characterized in that, the entrance pupil diameter of the second optical module is obtained based on the minimum allowable optical power received by the light-receiving module, the power of the laser pulses emitted by the light-emitting module, the scattering cross-section of the detection object, the area illuminated by the laser pulses, the entrance pupil vignetting coefficient, the preset limit range of the laser measurement device, and the overall transmittance of the laser measurement device; wherein, when the entrance pupil of the second optical module is an unobstructed circular pupil, the entrance pupil vignetting coefficient is zero.

5. The laser measurement device according to claim 1, characterized in that, the effective focal length of the second optical module is obtained based on the distortion amount of the second optical module and the light-receiving half field of view angle of the second optical module.

6. The laser measurement device according to claim 1, characterized in that, the second optical module can make the chief rays of the laser pulses incident on the second optical module at different incident angles perpendicularly incident on the imaging surface of the light-receiving module.

7. The laser measurement device according to claim 1, characterized in that, the first optical module and the second optical module are two separate modules for transmitting and receiving; or the first optical module and the second optical module are the same module.

8. The laser measurement device according to claim 1, characterized in that, the first optical module and the second optical module are two separate modules for transmitting and receiving, and the height of the light-emitting module has a linear function relationship with the light-emitting half field of view angle of the first optical module.

9. The laser measurement device according to claim 8, characterized in that, the effective focal length of the first optical module is obtained based on the height of the light-emitting module and the light-emitting half field of view angle of the first optical module.

10. The laser measurement device according to claim 1, characterized in that, The first optical module includes one or more lenses; and / or, the second optical module includes one or more lenses.

11. The laser measurement device according to claim 10, wherein, the lens is a glass lens or a plastic lens.

12. The laser measurement device according to claim 1, wherein, the light receiving module includes a photoelectric sensor, and the photoelectric sensor includes at least one of a photodiode, an avalanche photodiode, a single photon avalanche diode, a multi-pixel photon counting device, or a silicon-based photomultiplier tube.

13. The laser measurement device according to claim 1, wherein, the light receiving module includes a photoelectric sensor, pixels in the photoelectric sensor are arranged in a linear array or a planar array, and the optical axis of the second optical module is perpendicular to the imaging surface of the photoelectric sensor.

14. The laser measurement device according to claim 1, wherein, the light emitting module includes a laser diode array or a light emitting diode array.

15. The laser measurement device according to claim 1, wherein, the light emitting module includes a vertical cavity surface emitting laser or an edge emitting laser.

16. The laser measurement device according to any one of claims 1-15, wherein, the operating wavelength of the first optical module, the wavelength of the laser pulse emitted by the light emitting module, and the response spectrum of the light receiving module match; and / or the operating wavelength of the second optical module, the wavelength of the laser pulse emitted by the light emitting module, and the response spectrum of the light receiving module match.

17. The laser measurement device according to claim 16, wherein, the operating wavelength includes at least one of 850nm, 905nm, 940nm, 1550nm.

18. The laser measurement device according to any one of claims 1-15, wherein, the laser measurement device further includes a driving circuit, and the driving circuit is electrically connected to the light emitting module for driving the light emitting module to emit light.

19. The laser measurement device according to any one of claims 1-15, wherein, the laser measurement device further includes a signal processing circuit, and the signal processing circuit is electrically connected to the light receiving module for processing the electrical signal to obtain three-dimensional information of the detected object.

20. The laser measurement device according to claim 19, wherein, the signal processing circuit is used to correct the position coordinates of the detected object in the plane perpendicular to the optical axis according to a preset distortion correction function.

21. The laser measurement device according to any one of claims 1-15, wherein, the laser measurement device further includes a scanning module, and the scanning module is located on the light emitting optical path and the light receiving optical path for changing the laser pulse from the light emitting module to be emitted in different transmission directions and conducting the laser pulse reflected by the detected object to the light receiving module.

22. A movable platform, wherein, comprising: a movable platform body; and The laser measurement device according to any one of claims 1-21, wherein the laser measurement device is mounted on the movable platform body.

23. The movable platform according to claim 22, wherein, the movable platform body includes at least one of a drone, an autonomous vehicle, an unmanned boat, and a robot.

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