Laser radar and its detection method

Abstract

The present invention provides a detection unit and detection method for a laser radar, and the laser radar. The detection unit can predict the positions of spots (302, 304) on a detector array (100) of reflected echoes based on the flight time of a detection beam, and read electrical signals from some of the photodetectors corresponding to the spots (302, 304). The detection method can predict the positions of spots (302, 304) on the detector array (100) based on the flight time of the detection beam, and then turn on only some of the photodetectors in the detector array (100) that correspond to the spots (302, 304) to read their electrical signals. This allows all of the received light to be detected without increasing the receiving field of view, suppressing interference from ambient light and effectively solving the problem of offset of the spots (302, 304) on the focal plane caused by optical path distortion due to mechanical deformation of the optical-mechanical structure.

Description

Technical Field

[0001] The present invention generally relates to the technical field of laser detection, and particularly relates to a detection unit with a dynamically adjustable photosensitive surface, a lidar including the detection unit, and a detection method thereof.

Background Art

[0002] A lidar system includes a laser emission system and a detection and light reception system. When the emitted laser hits a target, it is reflected and received by the detection system. By measuring the time it takes for the laser to travel to and from the target, the distance between the target and the lidar can be measured (time-of-flight method). When the scanning detection of the entire target area is completed, a three-dimensional imaging is finally realized. As a commonly used ranging sensor, lidar has advantages such as a long detection distance, high resolution, strong resistance to active interference, small volume, and light weight, and is widely applied in fields such as intelligent robots, drones, and autonomous driving.

[0003] Currently, in the actual application of lidar, since the emission optical path and the light reception optical path are not coaxial, the position of the imaging spot on the detector varies depending on the reflection distance. On the other hand, in the case of a coaxial lidar (for example, a lidar using a galvanometer scanner or something similar to a field scanning lidar), within the flight time, the minute rotation of the galvanometer scanner during the emission and reception processes of the laser can similarly cause spot deviation. Also, mechanical deformations due to causes such as hardware aging of the radar device, deformation of adhesives, and thermal expansion and contraction can cause an offset in the spot position on the detector. To solve these problems, it is necessary to expand the photosensitive area of the detector to ensure that the spot deviation is always within the photosensitive region of the detector.

[0004] However, increasing the photosensitive area of the detector expands the viewing angle of the light reception optical path, increases the ambient light, and reduces the ambient light suppression ability of the system. Also, an increase in the photosensitive area of the detector may also lead to an increase in dark current / dark count, reducing the small signal recognition ability of the system.

[0005] Currently, many lidars use avalanche photodiodes (APDs) as detectors. However, APDs have a fixed photosensitive surface size and cannot be dynamically adjusted.

[0006] The content described in the background art section is only the technology known to the applicant and does not necessarily represent the existing technology in the field. SUMMARY OF THE INVENTION

[0007] In view of at least one of the drawbacks of the prior art, the present invention provides a detection unit for a lidar, a lidar including the detection unit, and a detection method therefor.

[0008] The present invention A detector array including a plurality of individually addressable photodetectors, wherein the photodetectors are configured to receive an echo reflected by a target from a detection beam emitted from a lidar and convert the echo into an electrical signal, and a detector array; A control unit coupled to the detector array, configured to predict a spot position on the detector array of an echo reflected by a target from a detection beam emitted from a lidar based on a flight time of the detection beam, and read electrical signals of some of the plurality of photodetectors corresponding to the spot among the plurality of photodetectors. A control unit is provided, and a detection unit of a lidar is provided.

[0009] According to an aspect of the present invention, the photodetector includes a single-photon detector, the detection unit further includes a plurality of address lines respectively connected corresponding to the plurality of photodetectors, and the control unit is electrically connected to the plurality of photodetectors via the plurality of address lines to read electrical signals.

[0010] According to an aspect of the present invention, during operation of the lidar, the plurality of photodetectors are kept on.

[0011] The present invention A detector array including a plurality of individually addressable photodetectors, wherein the photodetectors are configured to receive an echo reflected by a target from a detection beam emitted from a lidar and convert the echo into an electrical signal. A control unit coupled to the detector array, configured to predict a spot position on the detector array of an echo reflected by a target from a detection beam emitted from a lidar based on a flight time of the detection beam, and turn on only a part of the photodetectors corresponding to the spot among the plurality of photodetectors and read their electrical signals. Further provided is a detection unit of a lidar including the control unit.

[0012] According to one aspect of the present invention, the detection unit further includes a drive circuit for each photodetector. The drive circuit includes a Zener diode. The photodetector is connected to a drive voltage via the Zener diode. The drive circuit further includes a switch element coupled to both ends of the Zener diode. The switch element is coupled to the control unit and is turned on and off by the control unit. When the switch element is turned on, the Zener diode is short-circuited and the photodetector is turned on. When the switch element is turned off, the Zener diode is not short-circuited and the photodetector is turned off.

[0013] According to one aspect of the present invention, the photodetector includes a single photon detector. The detection unit further includes a plurality of address lines connected corresponding to the plurality of photodetectors. The control unit is electrically connected to the plurality of photodetectors via the plurality of address lines and reads electrical signals.

[0014] The present invention further provides a lidar including the detection unit described above.

[0015] According to one aspect of the present invention, the lidar is configured to emit a laser beam for target detection, An output lens located downstream of the optical path of the laser device, the output lens being configured to receive the laser beam, modulate it, and then output it outside the lidar. A light receiving lens configured to receive an echo obtained by reflecting a laser beam emitted from the laser device by a target and to focus the echo on the detector array, the detector array being on the focal plane of the light receiving lens.

[0016] According to one aspect of the present invention, the control unit determines the spot position (x t , y t ) of the echo of the detection beam reflected by the target on the detector array according to the following formula.

Equation

[0017] According to one aspect of the present invention, the lidar includes A laser device configured to emit a laser beam for target detection, A field of view scanning device configured to reflect the laser beam outside the lidar and receive an echo obtained by reflecting the laser beam emitted from the laser device by a target. A light-receiving lens configured to focus an echo obtained by reflecting a laser beam emitted from the laser device by a target object onto the detector array, wherein the detector array is on the focal plane of the light-receiving lens.

[0018] According to one aspect of the present invention, the control unit determines the spot position (x t , y t ) of the echo obtained by reflecting the detection beam by the target object on the detector array by the following formula.

Equation

[0019] According to one aspect of the present invention, the control unit of the detection unit acquires the actual projection position of the radar echo on the detector array, calculates the offset ( JPEG0007702413000011.jpg56, JPEG0007702413000012.jpg66) between the position obtained by the formula and the actual projection position, and calculates the average offset amount from the offsets ( JPEG0007702413000013.jpg56, JPEG0007702413000014.jpg57) calculated multiple times ( JPEG0007702413000015.jpg57, configured to calculate the JPEG0007702413000016.jpg66) and correct the spot origin position using the average offset amount.

[0020] According to one aspect of the present invention, the lidar includes a plurality of the laser devices, the detector array includes a plurality of independent sub - area arrays, and each sub - area array constitutes one detection channel corresponding to one of the laser devices.

[0021] According to one aspect of the present invention, the laser device is an end - emitting laser device or a vertical - cavity surface - emitting laser device.

[0022] The present invention includes the step of emitting a detection beam to the outside of the lidar, the step of calculating the flight time from the time when the detection beam is emitted, the step of predicting the spot position on the detector array of the echo reflected by the target object based on the flight time, and the step of reading the electrical signals of some of the plurality of photodetectors corresponding to the spot, and also relates to the detection method of the lidar described above.

[0023] According to one aspect of the present invention, the lidar includes a laser device configured to emit a laser beam for target detection, an emission lens located downstream of the optical path of the laser device, which is configured to receive the laser beam, modulate it, and then emit it to the outside of the lidar, and a light - receiving lens configured to receive the echo of the laser beam emitted from the laser device and reflected by the target object and focus the echo on the detector array, where the detector array is on the focal plane of the light - receiving lens. The step of predicting the spot position on the detector array of the echo reflected by the target object based on the flight time includes the step of determining the spot position (x t , y t ) according to the following formula.

Number

[0024] According to one aspect of the present invention, the lidar further includes a laser device configured to emit a laser beam for target detection, a field-of-view scanning device configured to reflect the laser beam outside the lidar so that the echo reflected by the target of the laser beam emitted from the laser device can be received, and a light-receiving lens configured to focus the echo reflected by the target of the laser beam emitted from the laser device onto the detector array, wherein the detector array is on the focal plane of the light-receiving lens. The step of predicting the spot position on the detector array of the echo reflected by the target of the detection beam based on the flight time includes the step of determining the spot position (x t , y t ) according to the following formula.

Number

[0025] According to one aspect of the present invention, the detection method includes: Obtaining the actual projection position of the radar echo on the detector array; The offset ( JPEG0007702413000027.jpg56, JPEG0007702413000028.jpg66) between the position obtained by the formula and the actual projection position; Calculating the offsets ( JPEG0007702413000029.jpg56, JPEG0007702413000030.jpg67) calculated multiple times; JPEG0007702413000031.jpg56, JPEG0007702413000032.jpg66) from the offsets calculated multiple times; Further including correcting the spot origin position using the average offset amount.

[0026] According to one aspect of the present invention, the lidar includes a plurality of the laser devices, the detector array includes a plurality of independent sub - area arrays, each sub - area array corresponds to one of the laser devices, and when a laser beam is emitted from one of the laser devices, the electrical signals of the photodetectors in one sub - area array corresponding to the laser device are read.

[0027] The present invention The step of emitting a detection beam to the outside of the lidar; The step of calculating the time of flight from the time when the detection beam is emitted; The step of predicting the spot position on the detector array of the echo reflected by the target based on the time of flight; The step of controlling only a part of the plurality of photodetectors corresponding to the spot to be in an on state and reading their electrical signals, which also relates to the detection method of the lidar described above.

[0028] According to one aspect of the present invention, the lidar includes a laser device configured to emit a laser beam for target detection, an emission lens located downstream of the optical path of the laser device, which is configured to receive and modulate the laser beam and then emit it to the outside of the lidar, and a light receiving lens configured to receive an echo reflected by the target from the laser beam emitted from the laser device and focus the echo on the detector array, wherein the detector array is on the focal plane of the light receiving lens. The step of predicting the spot position on the detector array of the echo reflected by the target based on the time of flight includes the step of determining the spot position (x t , y t ) by the following formula.

Equation

[0029] According to one aspect of the present invention, the lidar includes a laser device configured to emit a laser beam for target detection, a field-of-view scanning device configured to reflect the laser beam outside the lidar so as to receive an echo reflected by a target from the laser beam emitted from the laser device, and a light receiving lens configured to focus an echo reflected by a target from the laser beam emitted from the laser device on the detector array, wherein the detector array is on the focal plane of the light receiving lens, and the step of predicting the spot position of the echo reflected by the target by the detection beam on the detector array based on the time of flight includes determining the spot position (x t , y t ) including the step of.

Equation

[0030] According to one aspect of the present invention, the detection method includes the step of obtaining the actual projection position of the radar echo on the detector array, The offset between the position obtained by the above formula and the actual projection position ( JPEG0007702413000043.jpg56, JPEG0007702413000044.jpg67) is calculated, and the offsets calculated multiple times ( JPEG0007702413000045.jpg56, JPEG0007702413000046.jpg66) to calculate the average offset amount ( JPEG0007702413000047.jpg56, JPEG0007702413000048.jpg66), and correcting the spot origin position using the average offset amount.

[0031] According to one aspect of the present invention, the lidar includes a plurality of the laser devices, the detector array includes a plurality of independent sub-area arrays, each sub-area array corresponds to one of the laser devices, and when a laser beam is emitted from one of the laser devices, the electrical signals of the photodetectors in one sub-area array corresponding to the laser device are read.

[0032] A preferred embodiment of the present invention provides a detection unit of a lidar that can predict the spot position on the detector array of the reflected echo based on the flight time of the detection beam and read the electrical signals of some photodetectors corresponding to the spot. A preferred embodiment of the present invention further provides a detection method that can predict the spot position on the detector array of the reflected echo based on the flight time of the detection beam and dynamically adjust the photosensitive area based on this. The present invention can detect all received light without increasing the light reception field of view, suppress the interference of ambient light, and effectively solve the problem of spot position offset in the focal plane caused by the optical path distortion due to the mechanical deformation of the optomechanical structure.

Brief Description of the Drawings

[0033] The drawings forming a part of the specification are for further understanding of the present invention and for interpreting the present invention together with the embodiments of the present invention, and are not intended to limit the present invention. The description of the drawings will be described below.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0034] In the following, several exemplary embodiments will be briefly described. As can be understood by those skilled in the art, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be essentially exemplary and not restrictive.

[0035] In the description of the present invention, the orientation or positional relationship indicated by terms such as "center", "longitudinal direction", "lateral direction", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the drawings, and is merely for facilitating the description of the present invention and simplifying the description, and does not indicate or imply that the shown device or element must have a specific orientation or be configured and operated in a specific orientation. It should be understood that the present invention should not be regarded as being limited thereby. Also, the terms "first" and "second" are merely for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the shown technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more of the above-mentioned features. In the description of the present invention, unless clearly and specifically limited, "a plurality" means two or more.

[0036] In the description of the present invention, unless clearly defined and limited otherwise, the terms "attach", "connect", and "couple" should be understood in a broad sense. For example, they may be fixedly connected, removably connected, or integrally connected. Further, they may be mechanically connected, electrically connected, or communicatively connected to each other. Furthermore, they may be directly connected, indirectly connected through an intermediate medium, or may be in the form of internal communication between two elements or the interaction relationship between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific situation.

[0037] In the present invention, unless clearly defined or limited, the statement that the first feature is "above" or "below" the second feature may include the case where the first and second features are in direct contact, or may also include the case where the first and second features are not in direct contact and are in contact through another feature therebetween. Further, the statement that the first feature is "above", "upper" and "upper surface" of the second feature includes the case where the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The statement that the first feature is "below", "lower" and "lower surface" of the second feature includes the case where the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is smaller than that of the second feature.

[0038] In the following disclosure, many different embodiments or examples are provided for implementing different structures of the present invention. To simplify the disclosure of the present invention, in the following, members and settings of specific examples will be described. Of course, these are merely examples and are not intended to limit the present invention. Further, in the present invention, reference numerals and / or reference alphabets may be duplicated in different examples, and such duplication is for the purpose of simplification and clarity and does not itself indicate the relationship between various embodiments and / or settings to be considered. Also, although the present invention provides examples of various specific processes and materials, those skilled in the art can conceive of the application of other processes and / or the use of other materials.

[0039] In the following, embodiments of the present invention will be described with reference to the drawings, but it should be understood that the embodiments described herein are merely for explaining and interpreting the present invention and are not intended to limit the present invention.

[0040] FIG. 1 shows a schematic diagram of a detection unit 10 of a lidar according to an embodiment of the present invention. Hereinafter, a detailed description will be given with reference to the drawings. As shown in FIG. 1, the detection unit 10 includes a detector array 100 and a control unit 200. The detector array 100 includes a plurality of micro units, and the dashed line portion in FIG. 1 surrounds one micro unit. Each micro unit includes a photodetector 101 for converting an echo obtained by reflecting a detection beam emitted from the lidar by a target into an electrical signal. The photodetector is, for example, an avalanche photodiode (SPAD) having a single-photon detection ability. Hereinafter, the SPAD will be described as an example. When there is no light irradiation, the reverse current of the SPAD is very weak, but when at least one photon is incident on the SPAD, the reverse current rapidly increases avalanche-like. In order to prepare for the detection of the next photon, the generated avalanche current needs to be quenched in a timely manner. As shown in FIG. 1, the passive quenching pattern of the SPAD requires the co-action of the SPAD and the quenching resistor 103. When the SPAD generates a current due to light irradiation, the current generates a voltage drop across the quenching resistor 103, whereby the bias voltage of the diode is reduced below the reverse breakdown voltage value, preventing the occurrence of further avalanches. Since an address line 102 is drawn out for each SPAD, it can be individually addressed. The control unit 200 of the lidar is connected to a plurality of SPADs 101 via the plurality of address lines 102 and can selectively read electrical signals on some of the SPADs 101. For simplicity, FIG. 1 schematically shows only the connection of the control unit 200 to three address lines 102.

[0041] As shown in FIG. 2, the echo of the detection beam emitted from the lidar and reflected by the target forms a spot 202 on the detector array 100. The shaded area 203 in FIG. 2 covers the spot 202. Therefore, the control unit of the lidar can accurately detect the lidar echo by only reading the electrical signals of some of the SPADs 101 corresponding to the area 203, without reading the electrical signals output by the entire detector array 100. This is equivalent to a reduction in the effective photosensitive area of the detection unit, which can effectively suppress the influence of ambient light, reduce dark current / dark count, and improve the small-signal recognition ability of the system. The size of the shaded area 203 is approximately the same as the size of the spot 202, improving the ambient light suppression ability of the system.

[0042] FIG. 3 schematically shows a schematic diagram of dynamically adjusting the photosensitive area based on the time of flight.

[0043] As shown in FIG. 1, the control unit 200 is coupled to the detector array 100. According to an embodiment of the present invention, the control unit 200 predicts the spot position on the detector array 100 of the echo of the detection beam reflected by the target based on the time of flight t of the detection beam emitted from the lidar, and is configured to read only the output electrical signals of the photodetectors corresponding to the predicted spot position. Hereinafter, it will be described in detail with reference to FIG. 3. The solid circle in FIG. 3 schematically shows the initially set light-receiving spot position 302, that is, the position where the laser returned from infinity is focused on the detector array, and the dark area shows the initially set photosensitive surface 303. The photosensitive surface 303 can cover the first spot position 302. After the time of flight t, the spot position is offset, and the offset amount is obtained from the calculation described later. The dashed circle schematically shows the predicted light-receiving spot 304 after offset, and the bright area shows the adjusted photosensitive surface 305. The photosensitive surface 305 can cover the light-receiving spot 304.

[0044] According to an embodiment of the present invention, during the operation of the lidar, all of the plurality of photodetectors 101 are kept in an on state, and the addresses of some of the photodetectors 101 to be read in the detection unit are updated, that is, by reading the electrical signals of some of the photodetectors 101 corresponding to the adjusted photosensitive surface 305, the dynamic adjustment of the position of the effective photosensitive surface becomes possible. As a result, it is guaranteed that all optical signals can be effectively received, and there is no need to read the electrical signals of the photodetectors 101 other than the effective photosensitive surface, and the ambient light suppression ability of the system is improved.

[0045] FIG. 4 shows a detector array 100' of a lidar according to another embodiment of the present invention that can replace the detector array 100 in FIGS. 1 to 3. Hereinafter, with reference to the drawings, a detailed description will be given focusing on the differences from the detector array 100. Note that, unless otherwise stated, the features regarding the detector array 100 in FIGS. 1 to 3 are applicable to the detector array 100' shown in FIG. 4. As shown in FIG. 4, the detector array 100' includes a plurality of photodetectors 101, and the photodetectors 101 are arranged in an array and individually addressable, similar to the embodiments shown in FIGS. 1 to 3. All the photodetectors 101 in FIGS. 1 to 3 are always in an on state (the bias voltage of the micro unit is higher than the reverse breakdown voltage), and the control unit reads only the electrical signals of some of the SPADs 101. In the embodiment of FIG. 4, the control unit 200 (see FIG. 1) is coupled to the detector array 100' and is configured to predict the spot position on the detector array of the echo reflected by the target object based on the flight time of the detection beam emitted from the lidar. The difference from the embodiments described in FIGS. 1 to 3 is that in the embodiment of FIG. 4, the control unit 200 turns on only some of the photodetectors 101 corresponding to the spot in the detector array 100 and reads their electrical signals, and the other photodetectors 101 are in an off state (the bias voltage of the micro unit is lower than the reverse breakdown voltage), and the off state means not responding regardless of whether photons are irradiated or not. In FIG. 4, the photodetector at the central position of the photodetector array, for example, the photodetector indicated by the dashed frame, is displayed in a different color from the surrounding photodetectors to indicate that it is in an on state capable of sensing the lidar echo. On the other hand, the surrounding photodetectors are in an off state and cannot sense the lidar echo.

[0046] Therefore, according to a preferred embodiment of the present invention, in addition to a plurality of address lines for connecting to the photodetector to read an electrical signal, the control unit 200 further includes a plurality of enable lines respectively coupled to the photodetector 101 to control the on / off of the photodetector 101 (the quenching method is not shown in the figure for simplification), which will be described in detail below.

[0047] FIG. 5 shows a drive circuit for each photodetector 101 according to an embodiment of the present invention. As shown in FIG. 5, the drive circuit includes a Zener diode 104 and a switch element 105. The photodetector 101 is connected to a drive voltage via the Zener diode 104. The switch element 105 is coupled to both ends of the Zener diode 104 and is controlled to be turned on / off by the control unit 200. For example, the control unit 200 may be coupled to the control end of the switch element 105 to control the on / off of the switch element 105 and control the presence or absence of a short circuit of the Zener diode. For example, when the switch element 105 is turned on, the Zener diode 104 is short-circuited, and the photodetector 101 is turned on because it is directly coupled to the drive voltage V op When the switch element 105 is turned off, the Zener diode 104 is not short-circuited, and the voltage across the photodetector becomes the voltage obtained by subtracting V op from V zener (V zener is the Zener voltage across the Zener diode), which is lower than the reverse breakdown voltage V BR of the photodetector 101, so the photodetector 101 is turned off. According to an embodiment of the present invention, the Zener voltage V zener of the Zener diode ≧ V ov (V ov is the excess bias voltage of the photodetector 101), the drive voltage V op = V ov + V BR , and V op - V zener ≦ V BRIt satisfies the above. Since all of the above devices are semiconductor devices, in principle, they can be integrated circuits. By integrating them into each photodetector in this way, the function of quickly turning the photodetector on and off can be enabled.

[0048] According to an embodiment of the present invention, the switch element may include a field effect transistor FET in which the gate functions as a control terminal and is connected to the control unit 200 via an enable line, and the source and drain are respectively connected to both ends of the Zener diode. Alternatively, the switch element may include a bipolar junction transistor BJT. According to an embodiment of the present invention, the photodetector is a single photon detector.

[0049] The inventor has discovered that as the distance changes, there is also a certain change in the spot size. The size of the light-receiving spot is related to the size of the emission spot, the size of the light-receiving lens, the focal length, and the distance. The closer the target is, the larger the spot size becomes. When the distance between the target and the lidar is far, the spot size does not change significantly. Generally, within a range of several meters from the lidar, an obvious change in the spot size can be observed, and the specific numerical values can be obtained through optical simulation. Therefore, according to an embodiment of the present invention, when calculating and predicting the light-receiving spot 304 based on the time of flight, in addition to calculating the center position of the light-receiving spot 304, the size of the light-receiving spot 304 may also be calculated. For example, the longer the flight, the smaller the light-receiving spot 304 becomes. Conversely, the shorter the time of flight, the larger the light-receiving spot 304 becomes. Thus, the area of the photosensitive surface 305 can be adjusted appropriately. This will be described in detail with reference to FIG. 6. FIG. 6 shows two targets, a first target OB1 and a second target OB2, at different distances from the lidar. Among them, the first target OB1 is farther from the lidar. Generally, the farther the target is from the lidar, the closer the focusing position where the returned echo is focused by the light-receiving lens is to the focal plane of the lidar. Also, since all the photodetectors are arranged on the focal plane of the light-receiving lens, the spot irradiated by the echo on the photodetector array is small. Therefore, as shown in FIG. 6, the spot area irradiated by the echo generated from the first target OB1 on the photodetector array is significantly smaller than the spot area irradiated by the echo generated from the second target OB2 on the photodetector array.

[0050] According to a preferred embodiment of the present invention, as shown in FIG. 3, the size of the photosensitive surface to be set may be variable and is dynamically adjusted according to the distance of the target object. For example, when the target object is far away, the photosensitive surface is set small, that is, the electrical signals of a small number of photodetectors are read, or a small number of photodetectors are turned on to read their electrical signals. When the target object is close, the photosensitive surface is set large, that is, the electrical signals of a large number of photodetectors are read, or a large number of photodetectors are turned on to read their electrical signals, and the photosensitive area size is close to the size of the light receiving spot. Alternatively, in FIG. 3, the size of the photosensitive surface to be set may be constant. For example, it may be based on the spot size returned onto the focal plane from a target object at infinity. In this case, the intensity of the echo returned from a target object at a short distance is large. In this case, the electrical signals of some of the photodetectors actually irradiated by the spot are read, and it has no influence on the measurement. Or alternatively, photosensitive surfaces with different sizes are set for different target object distance ranges. For example, when the distance between the target object and the lidar exceeds 5 meters, the control unit selects the first photosensitive surface size, for example, the spot size returned onto the focal plane from a target object at infinity. When the distance between the target object and the lidar is less than 5 meters, the control unit selects the second photosensitive surface size, for example, the spot size returned onto the focal plane from a target object at 5 m.

[0051] The present invention also relates to a lidar including the detection unit 10 described above. This will be described in detail below with reference to FIG. 7.

[0052] According to a preferred embodiment of the present invention, the lidar 40 shown in FIG. 7 includes a laser device 401, an emission lens 402, a light receiving lens 405, and the above-described detection unit 10 (the detection unit 10 includes a detector array 100 and a control unit 200). The laser device 401 can emit a laser beam 403 for target detection. The emission lens 402 is located downstream of the optical path of the laser device 401, and is configured to receive and collimate the laser beam 403 and then emit it outside the lidar for detection of the target 404. The light receiving lens 405 is configured to receive the echo 406 reflected by the target 404 from the laser beam 403 emitted from the laser device and focus the echo on the detector array 100, and the detector array 100 is on the focal plane of the light receiving lens 405.

[0053] FIG. 7 shows a case where a paraxial optical path is adopted and the optical axis 407 of the emitted laser beam 403 is parallel to that of the light receiving lens 405. The offset amount from the origin o of the light receiving spot on the focal plane of the spot imaged by the laser at different reflection distances is a, where a is a function of the flight time t. The focal length of the light receiving lens 405 is f. When the emitted laser beam 403 is parallel to the optical axis 407 of the light receiving lens, the axial center distance between the emitted laser beam 403 and the light receiving lens 405 is h (i.e., the distance of the paraxial optical axis is h), and the flight distance is 520. Assuming that the distance between the emission lens 402 and the target 404 is d1 and the distance between the target 404 and the light receiving lens 405 is d2, the following relational expression holds.

Equation

[0054] For simplicity of explanation, in the following, the spot position is indicated by the coordinates of the spot center (i.e., the center coordinates of the circular spot shown in Fig. 3), and the X-Y coordinate system for explaining the spot position is shown in Fig. 3. As shown in Fig. 3, it is defined that the coordinates where the laser 408 returned from infinity is focused on the focal plane are the origin o(x0, y0) of the light-receiving spot of the channel. When the emitted laser beam 403 and the light-receiving optical axis 407 are parallel, the position (x t , y t ) of the spot on the focal plane and the flight time should satisfy the following formula.

Equation

[0055] In the above formula, the focal length f of the light-receiving lens, the speed of light C, and h x and h y (h x and h y are the components of the distance h of the paraxial optical axis in the x-axis and y-axis directions) are all constants, and t is the flight time calculated from the time when the laser device emits a pulse. From the formula, it can be seen that as the flight time t increases, the spot approaches the origin o(x0, y0).

[0056] From the relationship between the spot coordinates and the flight time above, it can be seen that the theoretically appearing position of the spot can be calculated in real time based on the time the laser has flown. Furthermore, by referring to the above-mentioned setting selection of the photosensitive area size (the size of the photosensitive surface), the reading address of the detector array is planned in real time. Thereby, the detection unit composed of the detector array can dynamically and quickly adjust the position of the photosensitive area, realizing the detection of the received light and suppressing the interference of ambient light.

[0057] In another embodiment of the present invention, based on the time the laser has traveled, the theoretically predicted spot position is calculated in real time, and referring to the above-described setting selection of the photosensitive area size (the size of the photosensitive surface), some detectors can be turned on and planned in real time to read the signals. Thereby, the detection unit composed of the detector array can dynamically and rapidly adjust the position of the photosensitive area, realizing the detection of the received light and suppressing the interference of the ambient light.

[0058] FIG. 7 shows a case where the optical axis 407 of the emitted laser beam 403 and the light receiving lens 405 are parallel, and FIG. 8 shows a more general case. As shown in FIG. 8, the laser beam 403 emitted from a laser radar in a paraxial optical path usually forms an included angle θ with the optical axis 407 of the light receiving lens 405. Hereinafter, with reference to FIG. 8, the calculation of the position of the incident spot in a general case will be described. In FIG. 8, o' is the focusing position on the focal plane of the light receiving lens 405 of the echo returned from a target at infinity in the case of the included angle θ, and a is the offset amount of the actual spot focusing position with respect to o', which is also a function of the flight time t.

[0059] From the geometric relationship, it can be seen that the two shaded triangles in FIG. 8 are similar. Therefore, The relational expression of JPEG0007702413000054.jpg1023 holds. Rearranging this gives JPEG0007702413000055.jpg929.

[0060] Since h << d1, It may be regarded as JPEG0007702413000056.jpg531, and substituting it into the above formula gives JPEG0007702413000057.jpg1243.

[0061] The case where the emitted laser beam 403 and the optical axis 407 of the light receiving lens are not parallel is more general, and parallelism is only a special case of the model, that is, the case where θ = 0. Similarly, the position (x t , yt ) and the flight time should satisfy the following equation.

Equation

[0062] In the above equation, h x and h y are the x-axis and y-axis components of the distance h from the paraxial optical axis. By using the above equation, the spot positions at various angles can be predicted, and thus it becomes possible to adjust the photosensitive surface in real time according to the change in the light-receiving spot position.

[0063] Figures 7 and 8 show the calculation and prediction of the spot position in a paraxial optical path laser radar. Figure 9 shows an embodiment of a coaxial optical path laser radar.

[0064] According to another preferred embodiment of the present invention, the laser radar shown in Figure 9 includes a laser device 601, a field scanning device 602, and a light-receiving lens 606. The laser device 601 is configured to emit a laser beam 603 for target detection, and the laser beam 603 is incident on a beam splitter 608 (also called a coupler). The beam splitter 608 is, for example, a semi-transmissive and semi-reflective film that reflects a part of the laser beam 603 to the field scanning device 602. The field scanning device 602 is rotatable around the rotation axis oo, and rotates, for example, within the plane of the paper in Figure 9, and reflects the incident laser beam 603 to the outside of the laser radar along various directions for detecting the target 604. The laser beam 603 is diffusely reflected on the target 604, and a part of the echo 605 returns to the field scanning device 602, and the field scanning device 602 reflects the echo 605 to the beam splitter 608. The echo that passes through the beam splitter 608 and is transmitted is focused on the detector array 100 through the light-receiving lens 606, and the detector array 100 is on the focal plane of the light-receiving lens 606.

[0065] The visual field scanning device includes a galvanometer mirror or a swinging mirror. In the example where the galvanometer mirror is used as the visual field scanning device, when the laser is emitted, the optical axis 607 of the light receiving lens 606 can be made parallel to and even overlap with the emitted light beam 603, thus enabling the coincidence of the light receiving visual field and the emitted visual field.

[0066] However, since the galvanometer mirror realizes visual field scanning by high-speed rotation, after the flight time t has elapsed, when the echo from the emitted laser beam 603 is received again, the galvanometer mirror has already rotated by a certain angle θ(t). As a result, the included angle between the received light beam 605 passing through the light receiving lens 606 and the optical axis 607 of the light receiving lens becomes 2θ(t) (because the normal line is deflected by 9(t)).

[0067] Thus, the offset amount of the spot on the detection unit 100 is JPEG0007702413000059.jpg745.

[0068] It is defined that the intersection point on the focal plane of the optical axis 607 of the light receiving lens is the spot origin (x0, y0), and the coordinates (x t , y t ) on the focal plane of the spot and the flight time satisfy the following formula.

Equation

[0069] In the above formula, JPEG0007702413000061.jpg612 and JPEG0007702413000062.jpg712 are the components of JPEG0007702413000063.jpg69, JPEG0007702413000064.jpg69 is related to the vibration speed of the galvanometer mirror, If JPEG0007702413000065.jpg610 is known, the spot position can be accurately predicted from the above formula, and furthermore, the effective photosensitive surface of the detector array can be adjusted in real time.

[0070] In the above description, it is possible to calculate the position on the spot detection unit based on the time of flight for both the paraxial optical path lidar and the lidar based on the scanning field of view. During actual operation, due to causes such as mechanical aging deformation, adhesive deformation, and thermal expansion and contraction, the spot origin (x0, y0) may be offset, resulting in a situation where the theoretically calculated spot position (x t , y t ) may not match the coordinates (x’, y’) on the actual spot detection unit. In this case, correction is preferably required.

[0071] To solve the offset of the spot origin due to mechanical deformation, every time the actual spot position is detected, the offset amount can be calculated, and the difference between the theoretically calculated spot position (x t , y t ) and the coordinates (x’, y’) on the actual spot detection unit can be obtained. The calculation formula is as follows.

Equation

Equation

[0072] Since the progress of mechanical deformation is slow, to measure the offset amount more accurately and improve the robustness of the system, after measuring the offset amount over a long period of time, a more accurate result ( JPEG0007702413000068.jpg56, JPEG0007702413000069.jpg66) may be obtained. For example, take the average value of the offset amount 1000 times.

[0073] The accurate offset amount of the spot origin ( JPEG0007702413000070.jpg56, After obtaining JPEG0007702413000071.jpg66), in order to calculate the spot position based on the subsequent flight time more accurately, the original spot origin coordinates (x0, y0) are corrected to the new spot origin coordinates ( JPEG0007702413000072.jpg616, JPEG0007702413000073.jpg616).

[0074] According to a preferred embodiment of the present invention, the laser device at the emission end may include a plurality of end - emitting laser devices or vertical - cavity surface - emitting laser devices. The detector array may include a plurality of independent sub - area arrays on the focal plane of the light - receiving lens, and each sub - area array constitutes one detection channel corresponding to one of the laser devices. Alternatively, a large light - detector area array is arranged on the focal plane of the light - receiving lens, and different regions correspond to different laser devices to constitute one detection channel.

[0075] The present invention also relates to a method 700 for performing laser detection using the lidar 40 provided by the present invention. As shown in FIG. 10, specifically, Step S701 of emitting a detection beam to the outside of the lidar; Step S702 of calculating the flight time from the time when the detection beam is emitted; Step S703 of predicting the spot position on the detector array of the echo reflected by the target object based on the flight time; Step S704 of reading the electrical signals of some of the plurality of photodetectors corresponding to the spot, are included.

[0076] The method for predicting the spot position based on the flight time in step S703 is determined by the structure of the lidar. In the case of a paraxial lidar or a galvanometer scanner lidar, the calculation formula for the spot position is shown in the above embodiments, so detailed description is omitted here. Since the correction method for the offset of the spot origin due to causes such as mechanical aging deformation, adhesive deformation, and thermal expansion and contraction is also shown above, detailed description is omitted here.

[0077] The detection method shown in FIG. 10 is also applicable to lidars with multiple channels. The lidar includes a plurality of laser devices, the detector array includes a plurality of independent sub-area arrays, each sub-area array corresponds to one of the laser devices, and when a laser beam is emitted from one of the laser devices, the electrical signals of the photodetectors in one sub-area array corresponding to the laser device are read.

[0078] The present invention also relates to a method 800 for performing laser detection using the lidar 40 provided by the present invention. As shown in FIG. 11, specifically, step S801 of emitting a detection beam to the outside of the lidar; step S802 of calculating the flight time from the time when the detection beam is emitted; step S803 of predicting the spot position on the detector array of the echo reflected by the target object based on the flight time; step S804 of controlling only a part of the plurality of photodetectors corresponding to the spot to be in an on state and reading their electrical signals.

[0079] The method for predicting the spot position based on the flight time in step S803 is determined by the structure of the lidar. In the case of a paraxial lidar or a galvanometer scanner lidar, the calculation formula for the spot position is shown in the above embodiment, so detailed description is omitted here. Since the correction method for the offset of the spot origin due to causes such as mechanical aging deformation, adhesive deformation, and thermal expansion and contraction is also shown above, detailed description is omitted here.

[0080] Since the method for controlling only a part of the photodetectors corresponding to the spot among the plurality of photodetectors in step S804 to be in the on state is shown in the above embodiment, detailed description is omitted here.

[0081] A preferred embodiment of the present invention provides a detection unit of a lidar whose photosensitive area is dynamically adjustable, and shows a method for calculating the spot position based on the flight time in different lidar structures. A preferred embodiment of the present invention further provides a method for performing laser detection by a dynamically adjusted photosensitive surface. Without increasing the light receiving field of view, all received light can be detected, the interference of ambient light is suppressed, and the problem of spot position offset in the focal plane caused by optical path distortion due to mechanical deformation of the optomechanical structure is effectively solved.

[0082] Finally, the following should be explained. The above are only preferred embodiments of the present invention and do not limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or perform equivalent substitutions on some of their technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall all be included in the protection scope of the present invention.

Claims

1. A lidar including a detection unit, wherein: the detection unit includes: a detector array including a plurality of individually addressable photodetectors, wherein the photodetectors are configured to receive an echo reflected by a target object from a detection beam emitted from the lidar and convert the echo into an electrical signal; a control unit coupled to the detector array, the control unit being configured to predict a spot position on the detector array of an echo reflected by a target object from a detection beam emitted from the lidar based on a flight time of the detection beam, and read electrical signals of some of the plurality of photodetectors corresponding to the spot; the lidar further includes: a laser device configured to emit a laser beam for target object detection; an output lens located downstream of an optical path of the laser device, the output lens being configured to receive and modulate the laser beam and then emit the laser beam outside the lidar; a light receiving lens configured to receive an echo reflected by a target object from a laser beam emitted from the laser device and focus the echo on the detector array, wherein the detector array is on a focal plane of the light receiving lens; the control unit determines a spot position (xt, yt) on the detector array of an echo reflected by a target object from the detection beam according to the following formula: 【Number 1】 wherein, 【Number】 ， 【Number】 () is a spot origin position, which is a spot position on the detector array of an echo reflected by a target object at infinity, f is a focal length of the light receiving lens, C is the speed of light, t is a flight time calculated from a time when the laser device emits a pulse, θ is an included angle between the laser beam emitted from the laser device and an optical axis of the light receiving lens, and () is a distance component along the x-axis and y-axis between the output lens and the light receiving lens. The lidar according to claim 1. 【Number】 ， 【Number】

2. The photodetector includes a single photon detector, the detection unit further includes a plurality of address lines respectively connected to the plurality of photodetectors, and the control unit is electrically connected to the plurality of photodetectors through the plurality of address lines to read electrical signals. The lidar according to claim 1.

3. ​ The lidar according to claim 1 or 2, wherein the plurality of photodetectors are kept on during operation of the lidar.

4. A lidar including a detection unit, wherein the detection unit is a detector array including a plurality of individually addressable photodetectors, the photodetectors being configured to receive an echo reflected by a target from a detection beam emitted from the lidar and convert the echo into an electrical signal; a detector array, a control unit coupled to the detector array, configured to predict a spot position on the detector array of an echo reflected by a target by a detection beam based on a flight time of the detection beam emitted from the lidar, and turn on only a part of the plurality of photodetectors corresponding to the spot and read their electrical signals; a control unit, wherein the lidar includes a laser device configured to emit a laser beam for target detection, an emission lens located downstream of the optical path of the laser device, the emission lens being configured to receive and modulate the laser beam and then emit it outside the lidar, a light receiving lens configured to receive an echo reflected by a target from a laser beam emitted from the laser device and focus the echo on the detector array, the detector array being on a focal plane of the light receiving lens, the control unit determines a spot position (x t, y t ) on the detector array of an echo reflected by a target by a detection beam according to the following formula, 【Number 2】 wherein ( 【Number】 ， 【Number】 ) is a spot origin position, the spot origin position being a spot position on the detector array of an echo reflected by a target at infinity, f is a focal length of the light receiving lens, C is the speed of light, t is a flight time calculated from the time when the laser device emits a pulse, θ is an angle between the laser beam emitted from the laser device and the optical axis of the light receiving lens, ( 【Number】 ， 【Number】 ) is a distance component along the x-axis and y-axis between the emission lens and the light receiving lens, a lidar.

5. Further comprising a drive circuit for each photodetector, the drive circuit including a Zener diode, the photodetector being connected to a drive voltage via the Zener diode, the drive circuit further including a switch element coupled to both ends of the Zener diode, the switch element being coupled to the control unit and being turned on and off by the control unit, when the switch element is turned on, the Zener diode is short-circuited, the photodetector is turned on, and when the switch element is turned off, the Zener diode is not short-circuited, the photodetector is turned off, the lidar according to claim 4.

6. The photodetector includes a single-photon detector, the detection unit further includes a plurality of address lines respectively connected corresponding to the plurality of photodetectors, and the control unit is electrically connected to the plurality of photodetectors via the plurality of address lines to read an electrical signal, the lidar according to claim 5.

7. A laser device configured to emit a laser beam for target detection, A field-of-view scanning device configured to reflect the laser beam outside the lidar so as to receive an echo reflected by the target from the laser beam emitted from the laser device, A light receiving lens configured to focus an echo reflected by a target from the laser beam emitted from the laser device onto the detector array, the detector array being on the focal plane of the light receiving lens, further comprising the light receiving lens, the lidar according to any one of claims 1 to 6.

8. The control unit determines the spot position (x t , y t ) on the detector array of the echo reflected by the detection beam from the target object according to the following formula, 【Number 3】 wherein, ( 【Number】 ， 【Number】 ) is the spot origin position, the spot origin position is the intersection of the optical axis of the light receiving lens and the detector array, f is the focal length of the light receiving lens, t is the flight time calculated from the time when the laser device emits a pulse, ( 【Number】 ， 【Number】 ) is the angular component by which the field-of-view scanning device rotates in the x direction and the y direction within the time t, the lidar according to claim 7.

9. The control unit of the detection unit acquires the actual projection position of the radar echo on the detector array, calculates the offset ( ， ) between the position obtained by the formula and the actual projection position, and from the offsets ( ， ) calculated multiple times, the average offset amount ( ， configured to calculate the ( ), and be able to correct the spot origin position using the average offset amount, the lidar according to any one of claims 1 to 6, 8. **Claim 10** The lidar includes a plurality of the laser devices, the detector array includes a plurality of independent sub-area arrays, and each sub-area array constitutes one detection channel corresponding to one of the laser devices, the lidar according to any one of claims 1 to 8. **Claim 11** The laser device is an end-face emitting laser device or a vertical cavity surface emitting laser device, the lidar according to any one of claims 1 to 8. **Claim 12** The step of emitting a detection beam to the outside of the lidar, The step of calculating the flight time from the time when the detection beam is emitted, The step of predicting the spot position on the detector array of the echo reflected by the target based on the flight time, The step of reading the electrical signals of some of the plurality of photodetectors corresponding to the spot, the detection method of the lidar according to any one of claims 1 to 6. The lidar includes a laser device configured to emit a laser beam for target detection, an emission lens located downstream of the optical path of the laser device, the emission lens being configured to receive and modulate the laser beam and then emit it outside the lidar, and a light receiving lens configured to receive an echo obtained by reflecting the laser beam emitted from the laser device by a target and focus the echo on the detector array, the detector array being on the focal plane of the light receiving lens. The step of predicting the spot position on the detector array of the echo obtained by reflecting the detection beam by a target based on the time of flight includes the step of determining the spot position (x t , y t ) according to the following formula. 【Number 4】 **Claim 13** 【Number】 ， 【Number】 wherein, ( 【Number】 ， 【Number】 ) is the spot origin position, the spot origin position is the spot position on the detector array of the echo reflected by a target at infinity, f is the focal length of the light receiving lens, C is the speed of light, t is the flight time calculated from the time when the laser device emits a pulse, θ is the included angle between the laser beam emitted from the laser device and the optical axis of the light receiving lens, ( ) is the distance component along the x-axis and y-axis between the emission lens and the light receiving lens, the detection method according to claim 12. The laser radar further includes a laser device configured to emit a laser beam for target detection, a field-of-view scanning device configured to reflect the laser beam outside the laser radar so as to receive an echo reflected by a target from the laser beam emitted from the laser device, and a light-receiving lens configured to focus an echo reflected by a target from the laser beam emitted from the laser device onto the detector array, wherein the detector array is on the focal plane of the light-receiving lens. The step of predicting a spot position on the detector array of an echo reflected by a target from the detection beam based on the time of flight includes determining the spot position (x t , y t ) by the following formula: 【Number 5】 **Claim 14** 【Number】 ， 【Number】 wherein, ( 【Number】 ， 【Number】 ) is the spot origin position, the spot origin position is the intersection of the optical axis of the light receiving lens and the detector array, f is the focal length of the light receiving lens, t is the flight time calculated from the time when the laser device emits a pulse, ( ) is the angle component by which the field of view scanning device rotates in the x-direction and y-direction within time t, the detection method according to claim 12. **Claim 15** The step of obtaining the actual projection position of the radar echo on the detector array, ， The step of calculating the offset ( ) between the position obtained by the formula and the actual projection position, ， The step of calculating the average offset amount ( ， ) from the offsets ( ) calculated multiple times, The method of detection according to claim 13 or 14, further comprising the step of correcting the spot origin position using the average offset amount.

16. The lidar includes a plurality of the laser devices, the detector array includes a plurality of independent sub-area arrays, each sub-area array corresponds to one of the laser devices, and when a laser beam is emitted from one of the laser devices, an electrical signal of a photodetector in one sub-area array corresponding to the laser device is read. The method of detecting a lidar according to any one of claims 12 to 14.

17. The step of emitting a detection beam to the outside of the lidar; The step of calculating the flight time from the time when the detection beam is emitted; The step of predicting the spot position on the detector array of the echo reflected by the target object based on the flight time; The method of detecting a lidar according to any one of claims 1 to 6, comprising the step of controlling only a part of the plurality of photodetectors corresponding to the spot to be in an on state and reading their electrical signals.

18. The laser radar further includes a laser device configured to emit a laser beam for target detection, an emission lens located downstream of the optical path of the laser device and configured to receive and modulate the laser beam and then emit it outside the laser radar, and a light-receiving lens configured to receive an echo obtained by reflecting the laser beam emitted from the laser device by a target and focus the echo on the detector array, where the detector array is on the focal plane of the light-receiving lens. The step of predicting the spot position on the detector array of the echo obtained by reflecting the detection beam by a target based on the time of flight includes determining the spot position (x t , y t ) according to the following formula. 【Number 6】 wherein ( 【Number】 ， 【Number】 ) is the spot origin position, the spot origin position is the spot position on the detector array of the echo reflected by a target object at infinity, f is the focal length of the light receiving lens, C is the speed of light, t is the flight time calculated from the time when the laser device emits a pulse, θ is the angle between the laser beam emitted from the laser device and the optical axis of the light receiving lens, and ( 【Number】 ， 【Number】 ) are the distance components along the x-axis and y-axis between the emission lens and the light receiving lens. The detection method according to claim 17.

19. The laser radar further includes a laser device configured to emit a laser beam for target detection, a field-of-view scanning device configured to reflect the laser beam outside the laser radar so as to receive an echo reflected by a target from the laser beam emitted from the laser device, and a light-receiving lens configured to focus an echo reflected by a target from the laser beam emitted from the laser device onto the detector array, wherein the detector array is on the focal plane of the light-receiving lens. The step of predicting a spot position on the detector array of an echo reflected by a target from the detection beam based on the time of flight includes determining the spot position (x t , y t ) by the following formula. 【Number 7】 wherein ( 【Number】 ， 【Number】 ) is the spot origin position, the spot origin position is the intersection of the optical axis of the light receiving lens and the detector array, f is the focal length of the light receiving lens, t is the flight time calculated from the time when the laser device emits a pulse, and ( 【Number】 ， 【Number】 ) are the angle components by which the field of view scanning device rotates in the x-direction and y-direction within time t. The detection method according to claim 17.

20. The step of obtaining the actual projection position of the radar echo on the detector array; The step of calculating an offset ( ， ) between the position obtained by the formula and the actual projection position; The step of calculating an average offset amount ( ， ) from the offsets ( ， ) calculated multiple times; The detection method according to claim 18 or 19, further comprising the step of correcting the spot origin position using the average offset amount.

21. The lidar includes a plurality of the laser devices, the detector array includes a plurality of independent sub-area arrays, each sub-area array corresponds to one of the laser devices, and when a laser beam is emitted from one of the laser devices, an electrical signal of a photodetector in one sub-area array corresponding to the laser device is read. The detection method of the lidar according to any one of claims 17 to 19.

Images