Underwater laser ranging device and ranging system

Abstract

The invention discloses an underwater laser ranging device and ranging system, the underwater laser ranging device comprises a laser, a reflective platform, a driving device, a visual sensor device and a plurality of first reflectors; wherein the driving device is used to drive the reflective platform to rotate around the central axis of the reflective platform; the side of the reflective platform is a reflective surface, the laser is used to project the laser onto the reflective surface along the incident direction of the reflective surface, the outgoing direction of the reflective surface is opposite to the incident direction of each first reflector, and the outgoing direction of each first reflector is used to face the target mesh; the visual sensor device is used to face the target mesh and collect the image projected by the laser onto the target mesh. The underwater laser ranging device disclosed by the invention can solve the technical problem that the existing point laser beam ranging method has extremely low ranging accuracy when used for flexible meshes.

Description

Technical Field

[0001] The invention belongs to the technical field of distance measuring devices, and in particular relates to an underwater laser distance measuring device and a distance measuring system. Background Art

[0002] At present, my country's fishery aquaculture has a development trend from offshore to deep sea. During the maintenance of aquaculture nets, it is necessary to obtain the distance between the operating mechanism and the net in real time to avoid entanglement between the operating mechanism and the net and ensure the safety and smoothness of the net maintenance operation.

[0003] The distance measurement between the operating mechanism and the net is mainly achieved through an underwater laser rangefinder. The currently commonly used underwater laser rangefinder is a single-point laser rangefinder based on the principle of phase laser ranging. It uses a modulation method to emit lasers and measures the phase difference to achieve ranging. However, nets and other meshes have a periodic fine line and mesh structure, and have the characteristics of a small ratio of the reflection area of ​​the acoustic and optical signals, that is, the target plane of the net is periodically hollow, and the point laser beam emitted by the underwater laser rangefinder may pass through the hollow area of ​​the mesh and fail to obtain the reflection signal, which makes it difficult for the underwater camera to collect a complete point laser spot image for ranging analysis; on the other hand, the aquaculture water in the deep sea environment has complex currents such as advection, turbulence, and internal waves, and the flexible structure of the net makes it have transient characteristics that fluctuate with the current. That is to say, the target plane of the net is in a state of continuous fluctuation and deformation, and the angle between it and the projection direction of the point laser beam is extremely complex, and there may be a mixture of rotation angle and pitch angle.

[0004] Based on the above problems, the traditional point laser beam ranging method has extremely low ranging accuracy when used for underwater nets. Therefore, there is an urgent need for an accurate and reliable ranging method for flexible meshes. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an underwater laser ranging device, which aims to solve the technical problem that the existing point laser beam ranging method has extremely low ranging accuracy when used for flexible mesh.

[0006] In order to achieve the purpose, the technical solution adopted by the present invention is as follows:

[0007] An underwater laser ranging device, comprising a laser, a reflection platform, a driving device, a visual sensor device and a plurality of first reflection mirrors; wherein:

[0008] The driving device is used to drive the reflection platform to rotate around the central axis of the reflection platform; the side of the reflection platform is a reflection surface, and the laser is used to project laser light onto the reflection surface along the incident direction of the reflection surface, and the emission direction of the reflection surface is opposite to the incident direction of each of the first reflection mirrors, and the emission direction of each of the first reflection mirrors is used to face the target mesh; the visual sensing device is used to face the target mesh and collect an image of the laser projected onto the target mesh.

[0009] Furthermore, the underwater laser ranging device also includes a second reflector; wherein:

[0010] The incident direction of the second reflector is opposite to the direction in which the laser projects the laser, and the emission direction of the second reflector is opposite to the incident direction of the reflective surface.

[0011] Furthermore, the underwater laser ranging device also includes a substrate, the laser, the driving device, the second reflector and a plurality of the first reflectors are mounted on a side surface of the substrate, and the central axis of the reflective platform is perpendicular to the substrate.

[0012] Further, the laser projects the laser in a direction toward the target mesh.

[0013] Further, the driving device is connected to the bottom surface of the reflecting platform, the visual sensing device is arranged on the top surface of the reflecting platform, and the central axis of the visual sensing device is located at the central axis of the reflecting platform;

[0014] Furthermore, in the direction of the central axis of the reflection platform, the distance difference between the imaging surface of the visual sensor device and the centers of the plurality of first reflection mirrors is no more than 1 mm.

[0015] Furthermore, the underwater laser ranging device also includes a base plate and a vibration reduction device, the base plate is installed on one side of the base plate, one end of the vibration reduction device is connected to one side of the base plate, and the other end of the vibration reduction device is connected to the driving device.

[0016] Furthermore, there are four first reflectors arranged around the reflective platform, so that the laser contour line projected from the exit surface of the first reflector is rectangular.

[0017] Furthermore, the reflection platform body is a regular quadrangular pyramid, the reflection surfaces are four side surfaces of the regular quadrangular pyramid, and the reflection surfaces are arranged in a one-to-one correspondence with the first reflectors.

[0018] Furthermore, the emission directions of any two opposite first reflectors are parallel to the central axis of the reflector body, and the emission directions of the other two first reflectors form an outward angle with respect to the central axis of the reflector body.

[0019] Correspondingly, the present invention also proposes a ranging system, which includes a circuit board and an underwater laser ranging device as described above; the circuit board is electrically connected to the laser, the driving device, and the visual sensing device, respectively, and the circuit board is used to connect to a terminal communication device.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The underwater laser ranging device proposed by the present invention drives the reflection platform to rotate by setting a driving device, sweeps the point laser beam projected by the laser onto the reflection surface of the reflection platform into a line laser beam and projects it onto the surface of the target mesh through the first reflector, solves the problem of being unable to obtain the reflection signal when the point laser beam is used because the point laser beam hits the hollow area of ​​the mesh, and enables the visual sensor device to collect the line laser beam hitting the mesh line of the target mesh and form a line laser spot on the imaging surface. In addition, since there are multiple first reflectors, there are also multiple line laser beams projected onto the target mesh. According to the imaging magnification relationship, the deflection angle of the target mesh can be derived by the distance relationship between the multiple line laser spots displayed on the imaging surface, so that the actual distance from the underwater ranging device to the surface of the target mesh can be more accurately calculated, thereby improving the ranging accuracy when the target mesh has fluctuation deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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 technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 It is a schematic structural diagram of an embodiment of an underwater laser ranging device of the present invention;

[0024] Figure 2 It is a schematic diagram of the outline of a linear laser beam projected onto a target mesh in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the first reflection trajectory of the laser in the embodiment of the present invention;

[0026] Figure 4 Schematic diagram of the second reflection trajectory of the laser in the embodiment of the present invention.

[0027] Description of reference numerals:

[0028]

[0029]

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0033] 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 implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] Reference Figures 1 to 3 An embodiment of the present invention provides an underwater laser ranging device, which includes a laser 1, a reflective platform 2, a driving device 3, a visual sensor device 4 and a plurality of first reflectors 5; wherein:

[0035] The driving device 3 is used to drive the reflection platform 2 to rotate around the central axis of the reflection platform 2; the side of the reflection platform 2 is a reflection surface 21, and the laser 1 is used to project the laser onto the reflection surface 21 along the incident direction of the reflection surface 21, and the emission direction of the reflection surface 21 is opposite to the incident direction of each first reflection mirror 5, and the emission direction of each first reflection mirror 5 is used to face the target mesh 10; the visual sensor device 4 is used to face the target mesh 10 and collect the image of the laser projected onto the target mesh 10.

[0036] In this embodiment, the target mesh 10 can be a net used for fish farming; the laser 1 is specifically an instrument that can emit a point laser beam to the target, and the wavelength of the point laser beam can be 660nm. The reflector body 2 is a prism structure that is narrow at the top and wide at the bottom, so that the reflective surface 21 is tilted downward in a direction away from the central axis of the reflector body 2, wherein the reflective surface 21 can be a reflective lens arranged on the side of the reflector body 2, or the reflector body 2 can be set as a reflective prism as a whole; the two end surfaces of the reflector body 2 are respectively the top surface (smaller area) and the bottom surface (larger area), and the central axis is perpendicular to the top surface and the bottom surface. The driving device 3 can specifically be a rotating motor, and its motor shaft can be connected to the center of the bottom surface of the reflector body 2, so that the reflective surface 21 of the reflector body 2 rotates around the central axis. The first reflectors 5 are preferably four, which can be arranged around the central axis of the reflector body 2 and radially outside the reflective surface 21. The first reflectors 5 can be tilted upward in a direction away from the central axis of the reflector body 2, that is, the first reflectors 5 are simultaneously facing the target mesh 10 and the reflective surface 21 of the reflector body 2. The visual sensor device 4 can be an underwater camera equipped with a laser light spot collection function and a corresponding image processing function. The laser beam hitting the mesh line of the target mesh 10 will be collected by the visual sensor device 4 and displayed in the form of a light spot on the imaging surface of the visual sensor device 4; the visual sensor device 4 can be packaged with waterproof and pressure-resistant materials and retain a flat glass window facing the target mesh 10. The installation position is not limited, and it only needs to ensure that the shooting direction faces the target mesh 10 and does not hinder the laser propagation. In addition, the underwater laser ranging device in this embodiment also needs to be integrated with a waterproof packaging process using pressure-resistant materials such as stainless steel and quartz, that is, the above components are all packaged in a pressure-resistant and waterproof sealed cabin to ensure normal operation underwater.

[0037] In the actual distance measurement process, multiple lasers 1 can be set and evenly distributed around the reflection platform 2. The point laser beam emitted by the laser 1 hits the reflection surface 21 of the reflection platform 2 (it can be directly projected or indirectly projected after reflection). When the driving device 3 drives the reflection platform 2 to rotate, the point laser beam hitting the reflection surface 21 is swept by the continuously rotating reflection surface 21 into a line laser beam. The line laser beam is transversely perpendicular to the emission direction of the laser 1 and is projected onto the first reflector 5 by the reflection surface 21. The first reflector 5 then projects the line laser beam onto the target mesh 10. The line laser beam can be regarded as a continuous line segment composed of a number of light spots. Therefore, no matter how the target mesh 10 fluctuates and deforms, there are always light spots on the continuous line laser beam that can hit the mesh line of the target mesh 10 and be collected by the visual sensor device 4 for subsequent distance measurement analysis. There is no problem of failing to obtain the reflection signal due to the point laser beam hitting the hollow area of ​​the mesh when the point laser beam method is used. In addition, since there are multiple first reflectors 5, the line laser beam is projected out from the exit direction of the first reflector 5 to form multiple line laser beams corresponding to the first reflectors 5 one by one. Figure 1 Taking the case where there are four first reflectors 5 as an example, when the first reflectors 5 are arranged in a rectangular shape around the reflector body 2, the number of line laser beams finally projected onto the target mesh 10 through the emission direction of the first reflectors 5 is also four, and the four line laser beams form a rectangle on the surface of the target mesh 10 (such as Figure 2 As shown). Under ideal conditions, the surface of the target mesh 10 is perpendicular to the projection direction of the line laser beam. At this time, the distances from the four line laser beams on the surface of the target mesh 10 to the imaging surface of the visual sensor device 4 are the same. According to the imaging magnification relationship, each line laser spot displayed on the imaging surface is from the center of the rectangle (the center of the rectangle refers to the point where the center point of the rectangle of the line laser beam on the surface of the target mesh 10 is projected onto the imaging surface, that is, Figure 2 The distance from the line laser spot to the corresponding line laser beam on the target mesh 10 is inversely proportional to the distance from the line laser spot to the corresponding line laser beam on the target mesh 10. Therefore, under ideal conditions, the distance from each line laser spot displayed on the imaging surface to the center of the rectangle is the same; when the target mesh 10 has a deflection angle due to fluctuation, the distances from each line laser spot on the imaging surface to the corresponding line laser beam on the target mesh 10 will be inconsistent. At this time, according to the imaging magnification relationship, the distances from each line laser spot on the imaging surface to the center of the rectangle are also inconsistent. In this way, the deflection angle of the target mesh 10 can be reversely deduced through the distance from each line laser spot on the imaging surface to the center of the rectangle, thereby calculating the actual distance from the underwater ranging device to the surface of the target mesh 10, thereby improving the ranging accuracy when the target mesh 10 has fluctuation deformation.

[0038] It can be seen that the underwater laser ranging device provided in this embodiment, by setting the driving device 3 to drive the reflection platform 2 to rotate, sweeps the point laser beam projected by the laser 1 onto the reflection surface 21 of the reflection platform 2 into a line laser beam and projects it onto the surface of the target mesh 10 through the first reflector 5, and solves the problem of being unable to obtain the reflection signal when the point laser beam is used because the point laser beam hits the hollow area of ​​the mesh, so that the visual sensor device 4 can collect the line laser beam hitting the mesh line of the target mesh 10 and form a line laser spot on the imaging surface. In addition, since there are multiple first reflectors 5, there are also multiple line laser beams projected onto the target mesh 10. According to the imaging magnification relationship, the deflection angle of the target mesh 10 can be derived through the distance relationship between the multiple line laser spots displayed on the imaging surface, so that the actual distance from the underwater ranging device to the surface of the target mesh 10 can be more accurately calculated, and the ranging accuracy is improved when the target mesh 10 has fluctuation deformation.

[0039] Specifically, refer to Figure 1 and Figure 3 , the underwater laser ranging device also includes a second reflector 6; wherein:

[0040] The incident direction of the second reflecting mirror 6 is opposite to the direction in which the laser 1 projects the laser light, and the emission direction of the second reflecting mirror 6 is opposite to the incident direction of the reflecting surface 21 .

[0041] In this specific embodiment, the point laser beam emitted by the laser 1 is projected onto the reflection surface 21 of the reflection platform 2 after being reflected once by the second reflection mirror 6. Figure 1 and Figure 3 As shown, since the reflective surface 21 needs to be set up and outward at the same time to ensure that the line laser beam can be projected onto the first reflector 5 and finally projected onto the target mesh 10, if the laser 1 is used to directly emit a point laser beam to the reflective surface 21, the laser 1 needs to be installed at the same height as the reflective surface 21 and at a certain distance from the reflective surface 21, and cannot interfere with the first reflector 5, which makes the installation and wiring of the laser 1 extremely inconvenient. Based on this, this specific embodiment adds a second reflector 6, so that the installation position of the laser 1 can be set more flexibly as needed, reducing the difficulty of installation and wiring. Among them, the number of second reflectors 6 can correspond to the laser 1 one by one.

[0042] Specifically, refer to Figure 1 The underwater laser ranging device also includes a substrate 7, a laser 1, a driving device 3, a second reflector 6 and a plurality of first reflectors 5 are installed on one side surface of the substrate 7, and a central axis of the reflective platform 2 is perpendicular to the substrate 7.

[0043] Specifically, refer to Figure 1The direction in which the laser 1 projects the laser light is used to be toward the target mesh 10 .

[0044] Specifically, refer to Figure 1 , the driving device 3 is connected to the bottom surface of the reflecting platform body 2, the visual sensing device 4 is arranged on the top surface of the reflecting platform body 2, and the central axis of the visual sensing device 4 is located at the central axis of the reflecting platform body 2;

[0045] The underwater laser ranging device in this embodiment needs to ensure the ranging accuracy and the accuracy of the laser beam projection angle, so it is necessary to ensure the accuracy and stability of the relative positions between the various reflectors. Therefore, in this specific implementation, a unified installation reference surface (substrate 7) is set for the laser 1, the drive device 3, the second reflector 6 and the first reflector 5, so that the above-mentioned components have a good geometric fixed relationship, thereby improving the accuracy and stability of the laser beam projection.

[0046] Diagrammatically, the driving device 3 is arranged at the center of the substrate 7, the laser 1 is arranged around the driving device 3, one end of the laser 1 is connected to the substrate 7, and the other end (transmitting end) faces the target mesh 10. Based on the installation method of the driving device 3 and the laser 1, the installation position of other reflectors used in conjunction with the laser 1 can also be correspondingly retracted inward (close to the direction of the central axis of the reflective platform 2). The visual sensor device 4 is arranged on the reflective platform 2 to ensure that it does not occupy the rest of the space, and the visual sensor device 4 is located at the center to improve the quality of the collected laser spot image. Through the above structural layout, the space of the underwater laser ranging device in the radial direction is saved.

[0047] Specifically, refer to Figure 1 In the central axis direction of the reflection platform 2, the distance difference between the imaging surface of the visual sensor device 4 and the centers of the plurality of first reflection mirrors 5 is no more than 1 mm.

[0048] In this specific embodiment, diagrammatically, taking the direction toward the surface of the target mesh 10 as the height direction, the plurality of first reflectors 5 are preferably at the same height position, and the height plane through which the centers of the first reflectors 5 pass together is taken as the reference plane, and the height difference between the imaging plane of the visual sensor device 4 and the reference plane is not greater than 1 mm, and preferably, the imaging plane of the visual sensor device 4 and the reference plane are at the same height, so that a better laser spot imaging effect can be obtained.

[0049] Specifically, refer to Figure 1 The underwater laser ranging device also includes a base plate 8 and a vibration reduction device 9. The base plate 7 is installed on one side of the base plate 8. One end of the vibration reduction device 9 is connected to one side of the base plate 8, and the other end of the vibration reduction device 9 is connected to the driving device 3.

[0050] The driving device 3 generates vibration and noise during operation. In this specific embodiment, the vibration generated by the driving device 3 can be transmitted to the bottom plate 8 by setting a vibration reduction device 9, thereby reducing the noise. Preferably, there are multiple vibration reduction devices 9 and they are arranged at each corner of the driving device 3. The vibration reduction device 9 may include elastic parts, dampers, hydraulic or pneumatic shock absorbers and other devices, which are not limited here.

[0051] Specifically, refer to Figure 1 There are four first reflectors 5 disposed around the reflector body 2 so that the laser contour line projected from the exit surface of the first reflector 5 is rectangular.

[0052] Specifically, refer to Figure 1 The reflecting platform body 2 is a regular quadrangular pyramid, the reflecting surfaces 21 are the four side surfaces of the regular quadrangular pyramid, and the reflecting surfaces 21 and the first reflecting mirrors 5 are arranged in a one-to-one correspondence.

[0053] Specifically, refer to Figure 1 , Figure 3 and Figure 4 The emission directions of any two opposite first reflectors 5 are parallel to the central axis of the reflector body 2 , and the emission directions of the other two first reflectors 5 form an outward angle relative to the central axis of the reflector body 2 .

[0054] In the above specific embodiment, when the first reflectors 5 are arranged in a rectangular shape around the reflector body 2, the number of line laser beams finally projected onto the target mesh 10 through the emission direction of the first reflector 5 is also four, and the four line laser beams form a rectangular light spot on the surface of the target mesh 10. Preferably, the first reflectors 5 are arranged in a square shape around the reflector body 2, so that the four line laser beams form a square light spot on the surface of the target mesh 10. Based on the arrangement of the first reflector 5, the laser 1 and the second reflector 6 can also be correspondingly arranged as follows: Figure 1 The reflecting platform body 2 is configured as a regular tetrahedron, and each reflecting surface 21 is preferably opposite to each first reflecting mirror 5, so that the straightness of the line laser beam can be improved in the two processes of converting the point laser beam into a line laser beam and projecting the line laser beam onto the first reflecting mirror 5.

[0055] like Figure 3As shown, when the emission directions of any two opposite first reflectors 5 are parallel to the central axis of the reflector body 2, if the target mesh 10 has a deflection angle relative to the direction of the line connecting the two reflectors 2 due to fluctuation, the distances from the two line laser spots corresponding to the two first reflectors 5 on the imaging surface of the visual sensor device 4 to the corresponding line laser beams on the target mesh 10 will be inconsistent. At this time, according to the imaging magnification relationship, the distances from the two line laser spots on the imaging surface to the center of the rectangle are also inconsistent. In this way, the deflection angle of the target mesh 10 relative to the direction of the line connecting the two reflectors 2 can be reversely deduced through the distances from each line laser spot on the imaging surface to the center of the rectangle (i.e., the point where the center point of the line laser beam rectangle on the surface of the target mesh 10 is projected onto the imaging surface).

[0056] like Figure 4 As shown, when the emission directions of the other two opposite first reflectors 5 are at an outward angle relative to the central axis of the reflector body 2 (i.e. Figure 4 α in the image plane of the visual sensor 4 is preferably 6°), for the two line laser beams projected onto the target mesh 10 by the two first reflectors 5, the distances of the two line laser beams to the center of the rectangle will increase as the distance between the target mesh 10 and the visual sensor device 4 increases. Based on this, it can be understood that if the target mesh 10 has a deflection angle relative to the direction of the line connecting the two reflector bodies 2 due to fluctuation (one side is closer to the visual sensor device 4 than the other side), the distances of the two line laser spots corresponding to the two first reflectors 5 on the imaging plane of the visual sensor device 4 to the center of the rectangle will be inconsistent, and the distances of the two line laser spots corresponding to the two first reflectors 5 on the imaging plane of the visual sensor device 4 to the corresponding line laser beams on the target mesh 10 are also inconsistent. In this way, based on the difference in the distance relationship between the line laser spots corresponding to the two first reflectors 5, and then according to the imaging magnification relationship, the deflection angle of the target mesh 10 relative to the direction of the line connecting the two reflector bodies 2 can be reversely deduced.

[0057] In summary, when the target mesh 10 has a relatively complex wave deformation, combining the above two derivation methods can make it easier to determine the deflection angles of the target mesh 10 in two coordinate directions.

[0058] Correspondingly, an embodiment of the present invention also provides a ranging system, which includes a circuit board and an underwater laser ranging device in any of the above embodiments; the circuit board is electrically connected to the laser 1, the driving device 3, and the visual sensing device 4, respectively, and the circuit board is used to connect to the terminal communication equipment.

[0059] In this embodiment, the circuit board may specifically include a control chip, through which the terminal communication device can control the action mode of the laser 1, the driving device 3, and the visual sensor device 4 according to a predetermined program, and the visual sensor device 4 can also feed back the collected data to the terminal communication device. For the specific structure of the underwater laser ranging device, reference may be made to the above embodiments. Since the ranging system adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0060] It should be noted that other contents of the underwater laser ranging device and ranging system disclosed in the present invention can be found in the prior art and will not be described in detail here.

[0061] The above are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. An underwater laser ranging device, characterized in that: The underwater laser ranging device comprises a laser, a reflection platform, a driving device, a visual sensor device and a plurality of first reflection mirrors; wherein: The driving device is used to drive the reflection platform to rotate around the central axis of the reflection platform; the side of the reflection platform is a reflection surface, and the laser is used to project laser light onto the reflection surface along the incident direction of the reflection surface, and the emission direction of the reflection surface is opposite to the incident direction of each of the first reflection mirrors, and the emission direction of each of the first reflection mirrors is used to face the target mesh; the visual sensing device is used to face the target mesh and collect an image of the laser projected onto the target mesh.

2. The underwater laser ranging device according to claim 1, characterized in that: The underwater laser ranging device also includes a second reflector; wherein: The incident direction of the second reflector is opposite to the direction in which the laser projects the laser, and the emission direction of the second reflector is opposite to the incident direction of the reflective surface.

3. The underwater laser ranging device according to claim 2, characterized in that: The underwater laser ranging device also includes a substrate, the laser, the driving device, the second reflector and a plurality of the first reflectors are mounted on one side surface of the substrate, and the central axis of the reflective platform is perpendicular to the substrate.

4. The underwater laser ranging device according to claim 3, characterized in that: The laser projects laser light in a direction toward the target web.

5. The underwater laser ranging device according to claim 3, characterized in that: The driving device is connected to the bottom surface of the reflecting platform, the visual sensor device is arranged on the top surface of the reflecting platform, and the central axis of the visual sensor device is located at the central axis of the reflecting platform; And / or, in the central axis direction of the reflection platform, the distance difference between the imaging surface of the visual sensor device and the centers of the plurality of first reflection mirrors is no more than 1 mm.

6. The underwater laser ranging device according to claim 3, characterized in that: The underwater laser ranging device also includes a base plate and a vibration reduction device. The base plate is installed on one side of the base plate. One end of the vibration reduction device is connected to one side of the base plate, and the other end of the vibration reduction device is connected to the driving device.

7. The underwater laser ranging device according to claim 1, characterized in that: There are four first reflectors arranged around the reflective platform, so that the laser contour line projected from the exit surface of the first reflectors is rectangular.

8. The underwater laser ranging device according to claim 7, characterized in that: The reflection platform body is a regular quadrangular pyramid, the reflection surfaces are four side surfaces of the regular quadrangular pyramid, and the reflection surfaces are arranged in a one-to-one correspondence with the first reflection mirrors.

9. The underwater laser ranging device according to claim 7, characterized in that: The emission directions of any two opposite first reflectors are parallel to the central axis of the reflector body, and the emission directions of the other two first reflectors form an outward angle with respect to the central axis of the reflector body.

10. A distance measurement system, characterized in that: The ranging system includes a circuit board and an underwater laser ranging device as described in any one of claims 1 to 9; the circuit board is electrically connected to the laser, the driving device, and the visual sensing device, respectively, and the circuit board is used to connect to a terminal communication device.

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