Laser radar receiving system, laser radar and ranging intensity improvement method

Abstract

The present invention provides a laser radar receiving system, a laser radar, and a method for improving ranging intensity, which relate to the field of laser radar technology and are designed to solve the problem that the existing laser radar will deteriorate the signal-to-noise ratio of the received signal. The laser radar receiving system includes a receiving lens and a photodetector arranged in sequence along the return direction of the optical path, and the photodetector deviates from the focal plane of the receiving lens in the direction away from the receiving lens. The present invention prevents incident light at a large angle from irradiating the photodetector, ensuring that the photodetector can receive the center reflected signal light to the maximum extent. At the same time, when the receiving lens converges the proximal light, the converged light will be in front of the focal plane, and the photodetector is arranged at the rear end of the focal plane, so it is easier to avoid stray signals, thereby effectively improving the signal-to-noise ratio of the received signal.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar receiving system, a laser radar, and a method for improving ranging intensity. Background Art

[0002] The principle of laser scanning detection technology is: based on the measurement of the flight time of the laser beam, the laser pulse is emitted at a defined time interval, and the time interval between the emitted pulse and the received pulse is calculated by the timer to obtain the distance to the target. The pulsed laser beam passes through the scanning component inside the ranging sensor to form a scan, and the contour curve of the detected target is determined by the series of pulses received.

[0003] At present, the optical path of laser scanning sensors uses a separate optical path for transmitting and receiving, and a coaxial optical path. Specifically, the coaxial optical path is that the transmitting light is emitted at the center of the receiving lens, reflected after irradiating the detection object, and then the signal is received. Because the window cover installed by the laser radar transmits the echo itself, and there are problems such as rain, snow, and fog that interfere with the strong signal reflection at the near end, the received echo will be irradiated to the window cover or the rain, snow, and fog at the near end to produce the phenomenon of triggering distance. At the same time, affected by the signal delay of the receiving detector itself, when using SiPM (Silicon photomultiplier, silicon photomultiplier tube), APD (Avalanche Photo Diode) and other detection devices, it is impossible to complete the close-range ranging. Therefore, the ranging capability of the coaxial two-dimensional scanning laser radar cannot achieve a breakthrough. In addition, the scheme of using different axes of transmitting and receiving for long-distance ranging will still have the interference problem of rain, snow, and fog at the near end. At the same time, the rotation of the different axes of transmitting and receiving requires magnetic ring transmission, which affects the service life of the whole machine, or the use of large array detectors leads to high costs. Therefore, solving or improving the above problems and drawbacks is extremely important for the optical, mechanical, electrical and computing design and optimization of laser ranging equipment.

[0004] The traditional solutions to reduce the blind spot of ranging include the following: 1. Use amplifiers with different magnifications to amplify gradually, then extract the signal in the middle and set different thresholds to ensure the test of the near-end distance; 2. Change the sensitivity of the detector by applying different voltages to the detector to ensure the test of the near-end distance; 3. Split the light in the receiving optical path, one part to the PIN (Positive-Intrinsic-Negative, P-type semiconductor-impurity-N-type semiconductor) detector, and the main light split to the SiPM; 4. Use a strong and weak multiple emission method; 5. Use two threshold comparators to receive the optical path, one high and one low, to reduce the near-end blind spot; 6. Add an aperture inside the receiving lens and use the aperture to limit the light beam to reduce stray signals. Although these solutions can reduce the blind spot of laser radar ranging, the signal-to-noise ratio of the received signal is relatively low. Summary of the invention

[0005] The first object of the present invention is to provide a laser radar receiving system to solve the technical problem that the existing laser radar will deteriorate the signal-to-noise ratio of the received signal.

[0006] The laser radar receiving system provided by the present invention comprises a receiving lens and a photoelectric detector which are sequentially arranged along the return direction of the optical path. In the direction away from the receiving lens, the photoelectric detector deviates from the focal plane of the receiving lens.

[0007] Furthermore, the distance that the photoelectric detector deviates from the focal plane is L, where L=(1 / 5-1 / 2)×f, wherein f is the focal length of the receiving lens.

[0008] Furthermore, the receiving lens includes a positive lens group and a negative lens group arranged in sequence along the return direction of the light path, the positive lens group is configured to focus the signal light returned by the detection target, and the negative lens group is configured to direct the light focused by the positive lens group toward the photodetector.

[0009] Furthermore, the negative lens group includes a plano-concave lens and a bi-concave lens sequentially arranged along the return direction of the light path, the concave surface of the plano-concave lens faces the positive lens group, and / or the positive lens group includes a plano-convex lens, the plane of the plano-convex lens faces the negative lens group.

[0010] Furthermore, the photodetector is an array detector, which includes a plurality of pixels arranged in M ​​rows and N columns, and each row and column can be individually controlled to be turned on and off, wherein M and N are both integers, and M>1, N>1.

[0011] Furthermore, the type of the photodetector is any one of MPPC (Multi-Pixel Photon Counter), SiPM, SPAD (Single Photon Avalanche Diode) and APD.

[0012] The beneficial effects brought by the laser radar receiving system of the present invention are:

[0013] By making the photodetector deviate from the focal plane of the receiving lens in a direction away from the receiving lens by a certain distance, when the laser radar receiving system is working, on the one hand, after being received by the receiving lens, the incident light with a large angle will be scattered outside the receiving surface of the photodetector due to defocusing, so that the incident light with a large angle cannot irradiate the photodetector. At the same time, due to the defocusing setting of the photodetector, the light received in the central field of view is first focused and then scattered after passing through the focus, and the scattered light is consistent with the outer contour of the photodetector, thereby ensuring that the photodetector can receive the central reflected signal light to the maximum extent; on the other hand, the reflected noise signals of rain, snow and fog gathered at the near end are stronger than the target signals at the far end. At the same time, when the receiving lens gathers the near-end light, the converged light will be in front of the focal plane, and the photodetector is set at the rear end of the focal plane, so it is easier to avoid stray signals.

[0014] The laser radar receiving system can effectively improve the signal-to-noise ratio of the received signal through the above-mentioned setting, and the setting only changes the position of the photodetector, and no other components need to be set, thereby greatly reducing the volume of the laser radar receiving system. Moreover, since there is no need to set an aperture, the aperture suppresses the effective light signal, thereby preventing the intensity of the target signal from being weakened. In addition, the laser radar receiving system can receive stray signals and target signals at the same time, not only without the need to set components such as a spectrometer and a threshold comparator, but also without the need for multiple transmissions, which reduces the cost of the laser radar receiving system while improving the working efficiency of the laser radar receiving system.

[0015] The second object of the present invention is to provide a laser radar to solve the technical problem that the existing laser radar may deteriorate the signal-to-noise ratio of the received signal.

[0016] The laser radar provided by the present invention includes a MEMS (Micro-Electro-Mechanical System) galvanometer, a transmitting unit, a main control unit and the above-mentioned laser radar receiving system, wherein the MEMS galvanometer, the transmitting unit and the laser radar receiving system are all electrically connected to the main control unit.

[0017] Furthermore, the laser radar also includes a power supply unit, which is configured to provide electrical energy to electrical components of the laser radar.

[0018] The beneficial effects brought by the laser radar of the present invention are:

[0019] When the laser radar is working, the transmitting unit transmits a light signal to the MEMS galvanometer, which scans and transmits. Some light passes through the window and returns along the optical path. The main light source shines through the window to the detection target. After the signal returns, it is received by the laser radar receiving system and the echo signal is sent to the main control unit. The main control unit times the detection signal to obtain the detection distance, and arranges and summarizes the detection distances at multiple angles to form a point cloud.

[0020] By setting the above-mentioned laser radar receiving system in the laser radar, accordingly, the laser radar has all the advantages of the above-mentioned laser radar receiving system, which will not be described one by one here.

[0021] The third object of the present invention is to provide a method for improving ranging intensity to solve the technical problem that the existing laser radar deteriorates the signal-to-noise ratio of the received signal, thereby resulting in low ranging intensity.

[0022] The present invention provides a method for improving ranging intensity, and a laser radar receiving system avoids stray light when the above-mentioned photodetector is used as an array detector, comprising the following steps: making the distance between the window piece and the detection target greater than the set distance; using the photodetector to collect the received signal, the received signal includes a front-end signal and a rear-end signal, wherein the front-end signal is a stray signal, and the stray signal includes a window piece reflection signal and a reflection signal inside the laser radar receiving system; the rear-end signal is a target signal; controlling the opening and closing of the rows and columns of the photodetector, respectively detecting the changes of the front-end signal and the rear-end signal, closing the rows and columns with strong front-end signals to weaken the front-end signals; opening the rows and columns with strong rear-end signals to enhance the rear-end signals, and finally leaving the rows and columns with the weakest front-end signals and the strongest rear-end signals.

[0023] Furthermore, in the step of controlling the opening and closing of the rows and columns of the photodetectors, the closing control is performed from the edge rows and columns of the photodetectors toward the inside thereof.

[0024] The beneficial effects of the ranging strength improvement method of the present invention are:

[0025] The ranging intensity improvement method achieves the purpose of improving the ranging intensity by making the laser radar receiving system avoid stray light, specifically: after the photoelectric detector is installed, the window piece is installed so that the distance between the window piece and the detection target is greater than the set distance; the photoelectric detector is used to collect and receive the stray signal at the front end and the target signal at the back end; by controlling the opening and closing of the rows and columns of the photoelectric detector, the changes of the front-end signal and the back-end signal are detected respectively, and the row with the strongest reflection signal of the window piece is found and turned off, and at the same time, the increase and decrease of the target signal is observed, and the best turn-off row and column are found by switching, and the row with strong front-end signal is turned off to weaken the front-end signal; the row with strong back-end signal is turned on to enhance the back-end signal, and finally the row with the weakest front-end signal and the strongest back-end signal is left, so as to ensure that the signal-to-noise ratio reaches the optimal level, thereby achieving the purpose of improving the ranging intensity. This method of selectively turning off the rows and columns of the photoelectric detector can minimize the row and column pixels that receive stray light, and at the same time, it can turn on the row and column pixels that receive effective signals, so that the signal-to-noise ratio is improved to the greatest extent, thereby achieving the purpose of improving the ranging intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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 embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the principle of a laser radar provided by an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the structure of a laser radar receiving system provided in an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of the optical path of the laser radar receiving system provided by an embodiment of the present invention when receiving normal angle light;

[0030] Figure 4 A schematic diagram of the optical path of the laser radar receiving system provided in an embodiment of the present invention when receiving large-angle light;

[0031] Figure 5 A schematic diagram of the structure of a photoelectric detector of a laser radar receiving system provided in an embodiment of the present invention;

[0032] Figure 6 A schematic diagram of a received signal collected by a photoelectric detector of a laser radar receiving system provided in an embodiment of the present invention;

[0033] Figure 7A schematic diagram of a flow chart of a method for improving ranging strength provided in an embodiment of the present invention.

[0034] Description of reference numerals:

[0035] 010-LiDAR receiving system; 020-MEMS galvanometer; 030-transmitting unit; 040-main control unit;

[0036] 100-receiving lens; 200-photoelectric detector; 300-focal plane;

[0037] 110-plano-convex lens; 120-plano-concave lens; 130-biconcave lens;

[0038] 210-pixel. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. 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.

[0040] Figure 1 The schematic diagram of the principle of the laser radar provided in this embodiment. Figure 1 As shown, this embodiment provides a laser radar, including a MEMS galvanometer 020, a transmitting unit 030, a main control unit 040 and a laser radar receiving system 010, wherein the MEMS galvanometer 020, the transmitting unit 030 and the laser radar receiving system 010 are all electrically connected to the main control unit 040.

[0041] When the laser radar is working, the transmitting unit 030 transmits a light signal to the MEMS galvanometer 020. The MEMS galvanometer 020 scans and transmits. Part of the light passes through the window and returns along the optical path. The main light source shines through the window to the detection target. After the signal returns, it is received by the laser radar receiving system 010, and the echo signal is sent to the main control unit 040. The main control unit 040 times the detection signal to obtain the detection distance, and arranges and summarizes the detection distances at multiple angles to form a point cloud.

[0042] In this embodiment, the laser radar also includes a power supply unit, wherein the power supply unit is configured to provide electrical energy to electrical components of the laser radar.

[0043] By providing a power supply unit in the laser radar, power can be supplied to electrical components in the laser radar, thereby facilitating the use of the laser radar.

[0044] It should be noted that the working principle of the laser radar can be obtained by those skilled in the art based on the prior art. This embodiment does not make any improvements thereto, so it will not be described in detail.

[0045] In the following text, the specific structure and working principle of the laser radar receiving system 010 will be explained.

[0046] Figure 2 FIG. 1 is a schematic diagram of the structure of the laser radar receiving system 010 provided in this embodiment. Figure 2 As shown, the laser radar receiving system 010 provided in this embodiment includes a receiving lens 100 and a photodetector 200 arranged in sequence along the return direction of the optical path, wherein the photodetector 200 deviates from the focal plane 300 of the receiving lens 100 in a direction away from the receiving lens 100 .

[0047] Figure 3 A schematic diagram of the optical path of the laser radar receiving system 010 provided in this embodiment when receiving normal angle light, Figure 4 The schematic diagram of the optical path of the laser radar receiving system 010 provided in this embodiment when receiving large-angle light. Figure 3 and Figure 4 As shown, by making the photodetector 200 deviate from the focal plane 300 of the receiving lens 100 by a certain distance in the direction away from the receiving lens 100, when the laser radar receiving system 010 is working, on the one hand, the incident light with a large angle will be scattered outside the receiving surface of the photodetector 200 due to defocusing after being received by the receiving lens 100. For details, please refer to Figure 4 , so that the incident light at a large angle cannot irradiate the photodetector 200. At the same time, due to the defocus setting of the photodetector 200, the light received by the central field of view is first focused, and then dispersed after passing the focus, and the dispersed light matches the outer contour of the photodetector 200, thereby ensuring that the photodetector 200 can receive the central reflected signal light to the maximum extent; on the other hand, since the reflected noise signal of rain, snow, and fog gathered at the near end is stronger than the target signal at the far end, at the same time, when the receiving lens 100 gathers the near-end light, the converged light will be before the focal plane. For details, please refer to Figure 4 , and the photodetector 200 is arranged at the rear end of the focal plane, so it is easier to avoid stray signals.

[0048] The laser radar receiving system 010 can effectively improve the signal-to-noise ratio of the received signal through the above-mentioned setting, and the setting only changes the position of the photodetector 200, and no other components need to be set, thereby greatly reducing the volume of the laser radar receiving system 010. Moreover, since there is no need to set an aperture, the suppression of the effective light signal by the aperture is avoided, thereby preventing the intensity of the target signal from being weakened. In addition, the laser radar receiving system 010 can receive stray signals and target signals at the same time, not only without the need to set components such as a spectrometer and a threshold comparator, but also without the need for multiple transmissions, which reduces the cost of the laser radar receiving system 010 while improving the working efficiency of the laser radar receiving system 010.

[0049] It should be noted that, in this embodiment, Figure 3 As shown, the focal plane 300 refers to a plane passing through the focus F and perpendicular to the return direction of the light path; Figure 3 and Figure 4 From the perspective of , the left end is the front end of the focal plane 300, that is, the front end of the focus F, and the right end is the rear end of the focal plane 300, that is, the rear end of the focus F.

[0050] Please continue to refer to Figure 3 In this embodiment, the distance that the photodetector 200 deviates from the focal plane 300 is L, where L=(1 / 5-1 / 2)×f, where f is the focal length of the receiving lens 100 .

[0051] By setting the distance of the photodetector 200 away from the focal plane 300 to the above-mentioned L, while reducing the stray light received by the photodetector 200, it is also possible to increase the effective light received by the photodetector 200, thereby ensuring that the laser radar receiving system 010 of this embodiment is in a better working condition.

[0052] It should be noted that, in this embodiment, f in the figure is only a schematic diagram of the focal length of the receiving lens 100. In actual situations, the focal length is obtained through corresponding calculations, which are related to the lens parameters in the receiving lens 100. Among them, how to calculate the focal length is an existing technology well known to those skilled in the art, so it will not be described in detail.

[0053] Please continue to refer to Figure 3 and Figure 4 In this embodiment, the receiving lens 100 includes a positive lens group and a negative lens group arranged in sequence along the return direction of the light path, wherein the positive lens group is configured to focus the signal light returned by the detection target, and the negative lens group is configured to direct the light focused by the positive lens group toward the photodetector 200.

[0054] In the receiving lens 100 , the positive lens group and the negative lens group are combined to form a positive focal length lens. By using the receiving lens 100 , the light can be smoothly received.

[0055] Please continue to refer to Figure 3 and Figure 4 In this embodiment, the negative lens group includes a plano-concave lens 120 and a bi-concave lens 130 which are sequentially arranged along the return direction of the light path, wherein the concave surface of the plano-concave lens 120 faces the positive lens group.

[0056] This arrangement of the negative lens group can not only achieve effective focusing of light, but also has a simple structure and low cost.

[0057] Please continue to refer to Figure 3 and Figure 4 In this embodiment, the positive lens group includes a plano-convex lens 110, and the plane of the plano-convex lens 110 faces the negative lens group.

[0058] Figure 5 Schematic diagram of the structure of the photoelectric detector 200 of the laser radar receiving system 010 provided in this embodiment. Figure 5 As shown, in this embodiment, the photodetector 200 is an array detector. Specifically, the array detector includes a plurality of pixels 210, and the plurality of pixels 210 are arranged in M ​​rows and N columns, and each row and column can be individually controlled to be turned on and off, wherein M and N are both integers, and M>1, N>1.

[0059] By setting the photodetector 200 as an array detector, each row and column of the photodetector 200 can be turned on and off independently, so that the laser radar receiving system 010 can adjust the shutdown of the rows and columns through actual optical path testing during use to ensure that the photodetector 200 will not receive stray signals as much as possible.

[0060] In addition, the photodetector 200 is in the form of an array detector, and the receiving intensity of the photodetector 200 can be controlled by controlling the switches of the array detector rows, so that the laser radar receiving system 010 of this embodiment can increase the dynamic range of the photodetector 200 by adjusting the strength of the detection signal.

[0061] It should be noted that in order to suppress stray light, the traditional receiving optical path usually adopts the method of adding an aperture to suppress stray light, but this setting will also reduce the strength of the effective signal. In the present application, by using an array detector, the strength of the signal-to-noise ratio can be quantitatively tested, so as to selectively turn on and off the pixel 210.

[0062] Please continue to refer to Figure 5In this embodiment, M=28, N=28, and the 28 rows and 28 columns of the photodetector 200 each have a separate control unit, and by controlling a total of 56 rows and columns, it is ensured that the photodetector 200 is not affected by stray signals as much as possible. In other embodiments, M and N can also be other values.

[0063] As a specific embodiment, the side length of the photodetector 200 is 1 mm, the size of the pixel 210 is 25 μm, and the gap is 10 μm; the focal length f of the receiving lens 100 is 25 mm, and the photodetector 200 is set at a position 5 mm behind the focus, that is, L = 5 mm.

[0064] In this embodiment, the specific type of the photodetector 200 can be any one of MPPC, SiPM, SPAD and APD.

[0065] The present embodiment also provides a method for improving ranging intensity, and the laser radar receiving system 010 avoids stray light when using the above-mentioned photodetector 200 as an array detector, including the following steps: making the distance between the window piece and the detection target greater than the set distance; using the photodetector 200 to collect the received signal, the received signal includes the front-end signal and the back-end signal, wherein the front-end signal is a stray signal, the stray signal includes the window piece reflection signal and the reflection signal inside the laser radar receiving system 010, and the back-end signal is the target signal; controlling the opening and closing of the rows and columns of the photodetector 200, respectively detecting the changes of the front-end signal and the back-end signal, closing the rows and columns with strong front-end signals to weaken the front-end signals; opening the rows and columns with strong back-end signals to enhance the back-end signals, and finally leaving the rows and columns with the weakest front-end signals and the strongest back-end signals.

[0066] This method of selectively shutting down the rows and columns of the photodetector 200 can minimize the number of row and column pixels 210 receiving stray light, while enabling the row and column pixels 210 receiving valid signals, thereby maximizing the signal-to-noise ratio and achieving the purpose of improving the ranging strength.

[0067] Figure 6 Schematic diagram of the received signal collected by the photoelectric detector 200 of the laser radar receiving system 010 provided in this embodiment. Figure 6 As shown, the front-end signal is a spurious signal, the back-end signal is a target signal, and the horizontal axis is time. Through the above settings, most of the received signals are the back-end target signals, which maximizes the signal-to-noise ratio and thus achieves the purpose of improving the ranging strength.

[0068] In this embodiment, in the step of controlling the opening and closing of the rows of the photodetectors 200, the closing control is performed from the edge rows of the photodetectors 200 to the inside thereof. Such a configuration can improve the distance measurement intensity and the optical path test efficiency.

[0069] Figure 7 This is a flow chart of the ranging strength improvement method provided in this embodiment. Figure 7 As shown, a specific embodiment of the method for improving the ranging strength includes the following steps: S100: After the detector is installed, the window piece is installed and irradiated onto the detection target at a specified distance, and the distance between the detection target and the window piece is more than 5 meters; S200: Collecting the received signal strength, there are two received signals, the front-end signal is the window piece and the internal reflection signal, which is a stray signal, and the back-end signal is the detection target signal, which is the target signal; S300: Controlling the array detector, starting from the edge rows and columns and performing the shutoff control inward, and finding the row with the strongest window piece reflection signal; S400: Turning off the row with strong reflection signal and turning on the row with strong target signal, so as to finally leave the row with the weakest front-end signal and the strongest back-end signal.

[0070] In summary, the laser radar receiving system, laser radar and ranging intensity improvement method provided by the present application, on the one hand, the laser radar based on the MEMS galvanometer 020 can better reduce stray light by changing the distance between the photoelectric sensor and the receiving lens 100, wherein the stray light includes: 1. The light generated by the internal reflection of the laser radar receiving system 010; 2. The light generated by near-end rain, snow and fog; 3. The interference of large-angle sunlight noise light sources; on the other hand, the laser radar based on the use of an array detector can control the reception strength, and by selectively shutting down the rows and columns, the row and column pixels 210 that receive stray light can be minimized. At the same time, the row and column pixels 210 that receive valid signals can be turned on to maximize the signal-to-noise ratio, thereby improving the ranging intensity.

[0071] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

[0072] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0073] In the above embodiments, the descriptions of directions such as “left” and “right” are all based on the drawings.

[0074] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving ranging strength, It is characterized in that Using a LiDAR receiving system to avoid stray light includes the following steps: Make the distance between the window and the detection target greater than the set distance; A photoelectric detector (200) is used to collect a received signal, wherein the received signal includes a front-end signal and a back-end signal, wherein the front-end signal is a stray signal, and the stray signal includes a window sheet reflection signal and a reflection signal inside a laser radar receiving system; and the back-end signal is a target signal; Controlling the opening and closing of the rows of photodetectors (200), respectively detecting changes in the front-end signal and the rear-end signal, closing the rows with strong front-end signals to weaken the front-end signals; opening the rows with strong rear-end signals to strengthen the rear-end signals, and finally leaving the rows with the weakest front-end signals and the strongest rear-end signals; In the step of controlling the opening and closing of the rows and columns of the photodetectors (200), the closing control is performed from the edge rows and columns of the photodetectors (200) toward the inside thereof.

2. A laser radar receiving system, It is characterized in that The ranging intensity enhancement method applied to claim 1 comprises a receiving lens (100) and a photodetector (200) arranged in sequence along a return direction of an optical path, wherein the photodetector (200) deviates from a focal plane (300) of the receiving lens (100) in a direction away from the receiving lens (100).

3. The laser radar receiving system according to claim 2, It is characterized in that The distance that the photoelectric detector (200) deviates from the focal plane (300) is L, where L=(1 / 5-1 / 2)×f, wherein f is the focal length of the receiving lens (100).

4. The laser radar receiving system according to claim 2, It is characterized in that The receiving lens (100) comprises a positive lens group and a negative lens group arranged in sequence along the return direction of the light path, the positive lens group being configured to focus the signal light returned by the detection target, and the negative lens group being configured to direct the light focused by the positive lens group toward the photodetector (200).

5. The laser radar receiving system according to claim 4, It is characterized in that The negative lens group comprises a plano-concave lens (120) and a bi-concave lens (130) which are sequentially arranged along the return direction of the optical path, and the concave surface of the plano-concave lens (120) faces the positive lens group; and / or the positive lens group comprises a plano-convex lens (110), and the plane of the plano-convex lens (110) faces the negative lens group.

6. The laser radar receiving system according to any one of claims 2 to 5, It is characterized in that The photodetector (200) is an array detector, comprising a plurality of picture elements (210), the plurality of picture elements (210) being arranged in M ​​rows and N columns, each row and column being capable of being individually controlled to be turned on and off, wherein M and N are both integers, and M>1, and N>1.

7. The laser radar receiving system according to claim 6, It is characterized in that The type of the photodetector (200) is any one of MPPC, SiPM, SPAD and APD.

8. A laser radar, It is characterized in that It comprises a MEMS galvanometer (020), a transmitting unit (030), a main control unit (040) and a laser radar receiving system as described in any one of claims 2 to 7, wherein the MEMS galvanometer (020), the transmitting unit (030) and the laser radar receiving system are all electrically connected to the main control unit (040).

9. The laser radar according to claim 8, It is characterized in that The laser radar also includes a power supply unit, which is configured to provide electrical energy to electrical components of the laser radar.

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