阅读说明：本技术 一种调频连续波激光雷达 (Frequency modulation continuous wave laser radar ) 是由 胡小波 刘颖 杨迪 于 2021-08-31 设计创作，主要内容包括：本发明实施例公开了一种调频连续波激光雷达,包括：激光发射模块、光分路器、光扩束器、拍频模块、偏振镜、1/4波片、激光扫描模块、信号处理模块和光电探测器,光分路器的输入端与激光发射模块的输出端连接；光分路器的第一输出端输出发射激光,第一光分路器的第一输出端与激光扫描模块的输入端连接；光分路器的第二输出端输出本振激光,光分路器的第二输出端与光扩束器的输入端连接；光扩束器的输出端与拍频模块的第一输入端连接；拍频模块得到拍频信号；拍频模块与光电探测器连接；信号处理模块与光电探测器连接。通过光分路器、偏振镜与1/4波片,实现了信号空间混频,有效降低了光纤的使用,减小了激光雷达的体积,拓展了适用范围。(The embodiment of the invention discloses a frequency modulation continuous wave laser radar, which comprises: the device comprises a laser emission module, an optical splitter, an optical beam expander, a beat frequency module, a polarizer, an 1/4 wave plate, a laser scanning module, a signal processing module and a photoelectric detector, wherein the input end of the optical splitter is connected with the output end of the laser emission module; the first output end of the first optical splitter is connected with the input end of the laser scanning module; the second output end of the optical splitter outputs local oscillator laser, and the second output end of the optical splitter is connected with the input end of the optical beam expander; the output end of the light beam expander is connected with the first input end of the beat frequency module; the beat frequency module obtains beat frequency signals; the beat frequency module is connected with the photoelectric detector; the signal processing module is connected with the photoelectric detector. Through the optical splitter, the polarizer and the 1/4 wave plate, signal space frequency mixing is realized, the use of optical fibers is effectively reduced, the size of the laser radar is reduced, and the application range is expanded.)

1. A frequency modulated continuous wave lidar comprising: a laser emission module, an optical splitter, an optical beam expander, a beat frequency module, a polarizer, an 1/4 wave plate, a laser scanning module, a signal processing module and a photoelectric detector,

the optical splitter is used for splitting one input optical signal into two output optical signals, and the input end of the optical splitter is connected with the output end of the laser emission module;

the first output end of the first optical splitter is connected with the input end of the laser scanning module;

the second output end of the optical splitter outputs local oscillator laser, and the second output end of the optical splitter is connected with the input end of the optical beam expander;

the optical beam expander is used for expanding the wire harness diameter of the local oscillator laser, and the output end of the optical beam expander is connected with the first input end of the beat frequency module;

the laser scanning module receives the emitted laser from the optical splitter for emission and transmits the reflected laser to the beat frequency module; the output end of the laser scanning module is connected with the second input end of the beat frequency module;

the beat frequency module is used for carrying out spatial beat frequency on the reflected laser of the laser scanning module and the local oscillator laser of the optical splitter to obtain a beat frequency signal; the output end of the beat frequency module is connected with the input end of the photoelectric detector;

the signal processing module collects beat frequency signals of the beat frequency module through a photoelectric detector to perform signal processing, and the laser scanning module is controlled by the signal processing module; the input end of the signal processing module is connected with the output end of the photoelectric detector;

the polarizer and the 1/4 wave plate are sequentially positioned on a transmission path of the emitted laser light, so that the emitted laser light is converted from a linear polarization state to a circular polarization state;

the 1/4 wave plate and the polarizer are sequentially positioned on the transmission path of the reflected laser light, so that the reflected laser light is converted from a linear polarization state to an original polarization state;

the transmission direction of the emitted laser is perpendicular to the transmission direction of the reflected laser.

2. A frequency modulated continuous wave lidar as defined in claim 1 further comprising a fiber amplifier having an input connected to the first output of the optical splitter and an output connected to one side of the polarizer; the optical fiber amplifier, the polarizer and the 1/4 wave plate are sequentially positioned on a transmission path of the emitted laser.

3. A frequency modulated continuous wave lidar according to claim 1 or 2, wherein the beat module further comprises a beam splitter prism, the number of photodetectors is 2;

2 of the photodetectors are respectively defined as a first photodetector and a second photodetector;

a first input side of the beam splitter prism is connected with local oscillator laser;

the second input side of the beam splitter prism is connected with reflected laser;

the first output side of the beam splitting prism is connected with the input end of the first photoelectric detector;

the second output side of the beam splitting prism is connected with the input end of the second photoelectric detector;

the output end of the first photoelectric detector is connected with the input end of the signal processing module;

and the output end of the second photoelectric detector is connected with the input end of the signal processing module.

4. A frequency modulated continuous wave lidar as defined in claim 3 wherein the beamsplitter prism is a resonance-canceling beamsplitter prism.

5. A frequency modulated continuous wave lidar as defined in claim 3 further comprising a first focusing mirror and a second focusing mirror;

the first focusing mirror is used for reducing the diameter of a wire harness for transmitting laser, and the input side of the first focusing mirror is connected with the first output side of the beam splitter prism;

the output side of the first focusing mirror is connected with the input end of the first photoelectric detector;

the second focusing mirror is used for reducing the diameter of a beam of transmitted laser, and the input side of the second focusing mirror is connected with the second output side of the beam splitter prism;

and the output side of the second focusing mirror is connected with the input end of the second photoelectric detector.

6. A frequency modulated continuous wave lidar according to claim 1, 2, 4, or 5, wherein the lasing module comprises a driver and a laser; wherein the driver is connected to the laser to modulate the output frequency of the laser.

7. A frequency modulated continuous wave lidar according to claim 1, 2, 4, or 5, wherein the laser scanning module comprises at least two laser emitters, at least two of the laser emitters having different lasing directions;

a polygon mirror including a first rotation axis extending in a first direction and a plurality of mirror facets surrounding the first rotation axis;

a swing mirror including a second rotation axis extending in a second direction and a reflection surface parallel to the second rotation axis;

wherein the second direction intersects the first direction; the laser transmitter and the swing mirror are respectively arranged on the light incident side and the light emergent side of the prism surface of the polygon prism;

the polygon prism rotates around the first rotating shaft, so that the prism surface reflects laser beams emitted by at least two laser emitters onto the reflecting surface; the oscillating mirror oscillates around the second rotating shaft, so that laser beams emitted by at least two laser emitters are emitted in different directions.

8. A frequency modulated continuous wave lidar according to claim 1, 2, 4, or 5, wherein the photodetector comprises P receivers, P amplification units, and P sampling units, wherein P is a positive integer;

the receivers are used for receiving the reflected laser and converting optical signals into electric signals, and the output ends of the P receivers are respectively connected with the input ends of the P amplifying units;

the amplifying units are used for amplifying the electric signals, and the output ends of the P amplifying units are respectively connected with the input end of the sampling unit;

the sampling unit is used for sampling the amplified signals output by the amplifying unit, sampling data are transmitted to the signal processing module, and the P sampling units are respectively connected with the input end of the signal processing module.

9. A frequency modulated continuous wave lidar according to claim 1, 2, 4, or 5, wherein the signal processing module comprises: the device comprises an amplifier, a low-pass filter, an analog-to-digital conversion module and a processor;

the photoelectric detector, the amplifier, the low-pass filter and the analog-to-digital conversion module are sequentially connected with the processor.

Technical Field

The invention relates to the field of laser radar structures, in particular to a frequency modulation continuous wave laser radar.

Background

The laser radar is a radar system which emits a laser beam to detect characteristic quantities such as a position, a speed and the like of a target. The basic operating principle of lidar is to transmit a probe signal (laser beam) to a target and then compare the received signal reflected from the target (target echo) with the transmitted signal to complete the detection. At present, the laser radar is widely applied to vehicles driven intelligently, but a large number of optical fibers are needed to be used due to the fact that the laser radar needs to transmit a large number of optical signals, the size of the laser radar is too large, and the application range is limited.

Thus, there is a need for a better solution to the problems of the prior art.

Disclosure of Invention

Therefore, the embodiment of the invention provides the frequency modulation continuous wave laser radar, and the spatial frequency mixing of the local oscillator light beam signal and the echo signal is realized by using the combined arrangement of the optical splitter, the polarizer and the 1/4 wave plate in the scheme.

Specifically, the present invention proposes the following specific examples:

the embodiment of the invention provides a frequency modulation continuous wave laser radar, which comprises: the device comprises a laser emitting module, an optical splitter, an optical beam expander, a beat frequency module, a laser scanning module, a signal processing module and a photoelectric detector;

the optical splitter is used for splitting one input optical signal into two output optical signals, and the input end of the optical splitter is connected with the output end of the laser emission module;

the first output end of the first optical splitter is connected with the input end of the laser scanning module;

the second output end of the optical splitter outputs local oscillator laser, and the second output end of the optical splitter is connected with the input end of the optical beam expander;

the optical beam expander is used for expanding the wire harness diameter of the local oscillator laser, and the output end of the optical beam expander is connected with the first input end of the beat frequency module;

the laser scanning module receives the emitted laser from the optical splitter for emission and transmits the reflected laser to the beat frequency module; the output end of the laser scanning module is connected with the second input end of the beat frequency module;

the beat frequency module is used for carrying out beat frequency on the reflected laser of the laser scanning module and the local oscillator laser of the optical branching device to obtain a beat frequency signal; the output end of the beat frequency module is connected with the input end of the photoelectric detector;

the signal processing module collects beat frequency signals of the beat frequency module through a photoelectric detector to perform signal processing, and the laser scanning module is controlled by the signal processing module; the input end of the signal processing module is connected with the output end of the photoelectric detector;

the polarizer and the 1/4 wave plate are sequentially positioned on a transmission path of the emitted laser light, so that the emitted laser light is converted from a linear polarization state to a circular polarization state;

the 1/4 wave plate and the polarizer are sequentially positioned on the transmission path of the reflected laser light, so that the reflected laser light is converted from a linear polarization state to an original polarization state;

the transmission direction of the emitted laser is perpendicular to the transmission direction of the reflected laser.

In this embodiment, through using the polarizer with 1/4 wave plate's setting, realized the spatial mixing of local oscillator beam signal and echo signal to this, compare in the scheme that adopts optic fibre in the past, can effectively reduce the use amount of optic fibre, from this, effectively reduced laser radar's volume, and simplified laser radar's structure, expanded laser radar application scope.

In a specific embodiment, the optical fiber amplifier further comprises an optical fiber amplifier, wherein the input end of the optical fiber amplifier is connected with the first output end of the optical splitter, and the output end of the optical fiber amplifier is connected with one side of the polarizer; the optical fiber amplifier, the polarizer and the 1/4 wave plate are sequentially positioned on a transmission path of the emitted laser.

In a specific embodiment, the beat frequency module further includes a beam splitter prism, and the number of the photodetectors is 2;

the 2 photodetectors are respectively defined as a first photodetector and a second photodetector;

a first input side of the beam splitter prism is connected with local oscillator laser;

the second input side of the beam splitter prism is connected with reflected laser;

the first output side of the beam splitting prism is connected with the input end of the first photoelectric detector;

the second output side of the beam splitting prism is connected with the input end of the second photoelectric detector;

the output end of the first photoelectric detector is connected with the input end of the signal processing module;

and the output end of the second photoelectric detector is connected with the input end of the signal processing module.

In a specific embodiment, the splitting prism is a resonance-eliminating splitting prism.

In a specific embodiment, the frequency modulated continuous wave lidar further comprises a first focusing mirror and a second focusing mirror;

the first focusing mirror is used for reducing the diameter of a wire harness for transmitting laser, and the input side of the first focusing mirror is connected with the first output side of the beam splitter prism;

the output side of the first focusing mirror is connected with the input end of the first photoelectric detector;

the second focusing mirror is used for reducing the diameter of a beam of transmitted laser, and the input side of the second focusing mirror is connected with the second output side of the beam splitter prism;

and the output side of the second focusing mirror is connected with the input end of the second photoelectric detector.

In a specific embodiment, the laser emitting module comprises a driver and a laser; wherein the driver is connected to the laser to modulate the output frequency of the laser.

In a specific embodiment, the laser scanning module comprises at least two laser emitters, and the laser emitting directions of the at least two laser emitters are different;

a polygon mirror including a first rotation axis extending in a first direction and a plurality of mirror facets surrounding the first rotation axis;

a swing mirror including a second rotation axis extending in a second direction and a reflection surface parallel to the second rotation axis;

wherein the second direction intersects the first direction; the laser transmitter and the swing mirror are respectively arranged on the light incident side and the light emergent side of the prism surface of the polygon prism;

the polygon prism rotates around the first rotating shaft, so that the prism surface reflects laser beams emitted by at least two laser emitters onto the reflecting surface; the oscillating mirror oscillates around the second rotating shaft, so that laser beams emitted by at least two laser emitters are emitted in different directions.

In a specific embodiment, the photodetector includes P receivers, P amplifying units and P sampling units, where P is a positive integer;

the receivers are used for receiving the reflected laser and converting optical signals into electric signals, and the output ends of the P receivers are respectively connected with the input ends of the P amplifying units;

the amplifying units are used for amplifying the electric signals, and the output ends of the P amplifying units are respectively connected with the input end of the sampling unit;

the sampling unit is used for sampling the amplified signals output by the amplifying unit, sampling data are transmitted to the signal processing module, and the P sampling units are respectively connected with the input end of the signal processing module.

In a specific embodiment, the signal processing module includes: the device comprises an amplifier, a low-pass filter, an analog-to-digital conversion module and a processor;

the photoelectric detector, the amplifier, the low-pass filter and the analog-to-digital conversion module are sequentially connected with the processor.

Therefore, by using the optical splitter, the polarizer and the 1/4 wave plate, spatial frequency mixing of local oscillation light beam signals and echo signals is performed, the defect that the size is large due to the fact that optical fibers are needed to be adopted for signal transmission in the prior art is overcome, the using amount of the optical fibers is reduced, the effect of the size of the laser radar is effectively reduced, the structure of the laser radar is optimized, and the application range of the laser radar is expanded.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings required to be used in the embodiments will be briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope of the present invention. Like components are numbered similarly in the various figures.

Fig. 1 shows a schematic structural diagram of a frequency modulated continuous wave lidar according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another frequency modulated continuous wave lidar according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a laser scanning module in another frequency modulated continuous wave lidar according to an embodiment of the present invention;

fig. 4 shows a schematic structural diagram of a signal processing module of a frequency modulated continuous wave lidar according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a third frequency modulated continuous wave lidar according to an embodiment of the present invention.

Illustration of the drawings:

100-a laser emitting module; 101-an optical splitter; 102-a light beam expander; 103-beat frequency module;

104-laser scanning module;

105-a photodetector; 1051-a receiver; 1052-an amplifying unit; 1053-a sampling unit;

106-a signal processing module;

107-polarizer; 108-1/4 wave plates; 109-fiber amplifier;

113-an amplifier; 114-a low-pass filter; 115-analog-to-digital conversion module; 116-a processor;

210-a laser emitter; 220-a polygon prism; 230-a swing mirror; 21-a first direction; 22-a second direction;

2100-a first axis of rotation; 2200-a second rotation axis; 221-prism facets; 231-reflecting surface.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

Hereinafter, the terms "including", "having", and their derivatives, which may be used in various embodiments of the present invention, are only intended to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing, and should not be construed as first excluding the existence of, or adding to, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.

Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present invention belong. The terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in various embodiments of the present invention.

Example 1

Embodiment 1 of the present invention discloses a frequency modulated continuous wave laser radar, as shown in fig. 1, including: the laser scanning device comprises a laser emitting module 100, an optical splitter 101, an optical beam expander 102, a polarizer 107, an 1/4 wave plate 108, a beat frequency module 103, a laser scanning module 104, a signal processing module 106 and a photoelectric detector 105;

the optical splitter 101 is configured to split one input optical signal into two output optical signals, and an input end of the optical splitter 101 is connected to an output end of the laser emission module 100;

the first output end of the optical splitter 101 outputs the emitted laser, and the first output end of the first optical splitter 101 is connected with the input end of the laser scanning module 104;

the second output end of the optical splitter 101 outputs local oscillator laser, and the second output end of the optical splitter 101 is connected with the input end of the optical beam expander 102;

the optical beam expander 102 is used for expanding the beam diameter of the local oscillator laser, and the output end of the optical beam expander 102 is connected with the first input end of the beat frequency module 103;

the laser scanning module 104 receives the emitted laser from the optical splitter 101 for emission, and transmits the reflected laser to the beat frequency module 103; the output end of the laser scanning module 104 is connected with the second input end of the beat frequency module 103;

the beat frequency module 103 is configured to beat frequency between the reflected laser of the laser scanning module 104 and the local oscillator laser of the optical splitter 101 to obtain a beat frequency signal; the output end of the beat frequency module 103 is connected with the input end of the photoelectric detector 105;

the signal processing module 106 collects beat frequency signals of the beat frequency module 103 through the photoelectric detector 105 for signal processing, and the laser scanning module 104 is controlled by the signal processing module 106; the input end of the signal processing module 106 is connected with the output end of the photoelectric detector 105;

the polarizer 107 and the 1/4 wave plate 108 are sequentially located on the transmission path of the emission laser light, so that the emission laser light is converted from the linear polarization state to the original polarization state;

1/4 wave plate 108 and polarizer 107 are sequentially located on the transmission path of the reflected laser light, so that the reflected laser light is converted from the linear polarization state to the original polarization state;

the transmission direction of the emitted laser light is perpendicular to the transmission direction of the reflected laser light.

Specifically, the problem in the prior art is that the amount of used optical fibers is too large, which results in a large volume, so that the laser radar can only be applied to a limited area, and in the scheme of this embodiment, spatial frequency mixing of local oscillator beam signals and echo signals is performed by using an optical splitter, a polarizer and an 1/4 wave plate, so that the defect that the size is large due to the fact that a large number of optical fibers are needed for signal transmission in the prior art is overcome in an optical manner, the usage amount of the optical fibers is reduced, the size of the laser radar is effectively reduced, the structure of the laser radar is optimized, and the application range of the laser radar is expanded.

It should be noted that, the first optical splitter provided in this embodiment only needs to have a function of splitting one input optical signal into two output optical signals, and other optical splitters having two or more controlled outputs may also meet the above requirements. In actual operation, no limitation is made on the type, size and kind of the first optical splitter.

Specifically, in the present scheme, laser generated by the laser emission module 100 is divided into two paths through the optical splitter 101 for output, and one path is used for emitting laser and outputting the laser to the laser scanner; the other path is that the local oscillator laser is output to the optical beam expander 102;

the optical beam expander 102 expands the beam diameter of the local oscillator laser and outputs the expanded beam diameter to the beat frequency module 103; in addition, after the laser scanner obtains the emitted laser, the generated reflected laser is also transmitted to the beat frequency module 103, the beat frequency module 103 beats the received signal to obtain a beat frequency signal, and sends the beat frequency signal to the photodetector 105, the photodetector 105 performs photoelectric conversion and outputs the signal to the signal processing module 106 for processing, and in addition, the signal processing module 106 can also control the laser scanner.

Specifically, the laser emitting module 100 includes a driver and a laser; wherein the driver is connected to the laser to modulate the output frequency of the laser. The laser is a laser emitting module 100 that generates a continuous wave laser beam with a tunable wavelength. In practical application, a 1550nm laser can be selected to generate a 1550nm narrow-linewidth wavelength-adjustable continuous wave laser beam; of course, lasers with other wavelengths can be selected to generate laser beams with other wavelengths; as for the driver, it is used to generate a current in the shape of a linear triangular wave for modulating the output frequency of the laser.

Specifically, the driver may include: a laser diode modulator, or a laser electric field amplitude external modulator, or a phase modulator. Thus, the corresponding modulation mode can be laser diode direct modulation, laser electric field amplitude external modulation or optical external modulation implemented by a phase modulator.

Specifically, the optical beam expander 102 is used to expand the beam diameter (beam width) of the local oscillator beam signal. Because the wire harness diameter of the reflected signal is larger, in order to better perform coherent mixing on the local oscillator signal and the reflected signal, the local oscillator signal needs to be expanded to the size of the wire harness diameter of the reflected signal within a preset range.

Specifically, when light with a certain wavelength passes through the 1/4 wave plate 108, also called a quarter retardation plate, through the 1/4 wave plate 108, the phase difference between the emergent ordinary light and the emergent extraordinary light is 1/4.

In a specific embodiment, as shown in fig. 2, the fm cw lidar further includes a fiber amplifier 109, an input end of the fiber amplifier 109 is connected to the first output end of the optical splitter 101, and an output end of the fiber amplifier 109 is connected to one side of the polarizer 107; the optical fiber amplifier 109, the polarizer 107, and the 1/4 wave plate 108 are located in this order on the transmission path of the emitted laser light.

Specifically, the optical fiber amplifier 109 amplifies the intensity of the transmitted signal and suppresses noise, which is beneficial to subsequent signal processing.

Further, for better performing the light splitting process, the beat frequency module 103 further includes a light splitting prism, and the number of the photodetectors 105 is 2;

the 2 photodetectors 105 are defined as a first photodetector and a second photodetector, respectively;

the first input side of the beam splitter prism is connected with local oscillator laser;

the second input side of the beam splitter prism is connected with the reflected laser;

the first output side of the beam splitting prism is connected with the input end of the first photoelectric detector;

the second output side of the beam splitter prism is connected with the input end of the second photoelectric detector;

the output end of the first photoelectric detector is connected with the input end of the signal processing module 106;

the output of the second photodetector is connected to the input of the signal processing module 106.

Specifically, the beam splitter prism is a resonance elimination beam splitter prism.

In addition, optionally, in order to better perform the photoelectric conversion of the photodetector 105, the frequency modulated continuous wave lidar further includes a first focusing mirror and a second focusing mirror;

the first focusing mirror is used for reducing the diameter of a wire harness for transmitting laser, and the input side of the first focusing mirror is connected with the first output side of the beam splitter prism;

the output side of the first focusing mirror is connected with the input end of the first photodetector 105;

the second focusing mirror is used for reducing the diameter of a beam of transmitted laser, and the input side of the second focusing mirror is connected with the second output side of the beam splitter prism;

the output side of the second focusing mirror is connected with the input end of the second photoelectric detector.

Specifically, the specific focusing mirror is used to reduce the beam diameter (beam width) of the beat signal and focus the beat signal on the photodetector 105. The photodetector 105 is a multi-quadrant photodetector that includes a plurality of photosensitive regions. More laser beams in the beat signal can be detected through the plurality of sub-photosensitive regions in the first photoelectric detector and the second photoelectric detector, and the angular resolution is improved. Since the photosensitive area of the multi-quadrant photodetector 105 is small, it is necessary to focus the beat signal into a plurality of sub-photosensitive areas in the multi-quadrant photodetector 105.

In one particular embodiment, as shown in FIG. 3, the laser scanning module 104 includes: at least two laser transmitters 210, wherein the laser emitting directions of the at least two laser transmitters 210 are different; further comprising:

a polygon mirror 220 including a first rotation axis 2100 extending in the first direction 21 and a plurality of mirror facets 221 surrounding the first rotation axis 2100;

the oscillating mirror 230 includes a second rotation axis 2200 extending in the second direction 22 and a reflection surface 231 parallel to the second rotation axis 2200.

Wherein the second direction 22 and the first direction 21 intersect; the laser transmitter 210 and the swing mirror 230 are respectively arranged on the light-in side and the light-out side of the prism surface 221 of the polygon prism 220;

the polygon 220 rotates around the first rotation axis 2100, so that the prism surface 221 reflects the laser beams emitted from the at least two laser emitters 210 onto the reflection surface 231; the oscillating mirror 230 oscillates around the second rotation axis 2200 to make the laser beams emitted from the at least two laser emitters 210 emit in different directions.

In a specific embodiment, for example, the first direction is a horizontal direction and the second direction is a vertical direction; of course, the first direction may be a vertical direction, and the second direction may be a horizontal direction. Therefore, based on the combination of the swing mirror and the polygon mirror, the large-view-field high-angle resolution scanning of the emitted light beams is realized.

In addition, the laser beams emitted by the two laser emitters are controlled to emit in different directions in order to avoid interference. Therefore, interference can be avoided while a high laser point cloud sampling rate is achieved.

In a particular embodiment, as shown in fig. 4, the photodetector 105 includes P receivers 1051, P amplification units 1052, and P sampling units 1053, P being a positive integer;

the receivers 1051 are used for receiving the reflected laser and converting the optical signals into electrical signals, and the output ends of the P receivers 1051 are respectively connected with the input ends of the P amplifying units 1052;

the amplifying unit 1052 is used for amplifying the electrical signal, and the output ends of the P amplifying units 1052 are respectively connected with the input end of the sampling unit 1053;

the sampling unit 1053 is configured to sample the amplified signal output by the amplifying unit 1052, and transmit the sampled data to the signal processing module 106, and the P sampling units 1053 are respectively connected to the input end of the signal processing module 106.

Specifically, the multiple receivers 1051 are adopted, and the advantage is that each receiving period 1051 is a pixel point on the image, and a single laser beam is received by the multiple receivers 1051, which means that the area covered by the laser beam is characterized by more pixel points, so that the number of laser point clouds is increased, and the information expression of the target area is more thorough.

Illustratively, as shown in fig. 5, the signal processing module 106 includes: an amplifier 113, a low pass filter 114, an analog-to-digital conversion module 115, and a processor 116;

the photodetector 105, the amplifier 113, the low-pass filter 114, the analog-to-digital conversion module 115 and the processor 116 are connected in sequence.

Therefore, by using the polarizer and the 1/4 wave plate 108 in the scheme, spatial frequency mixing of local oscillation light beam signals and echo signals is performed, the defect that in the prior art, signal transmission is performed by a large number of optical fibers, so that the size is huge is overcome, the use amount of the optical fibers is reduced, the effect of the size of the laser radar is effectively reduced, the structure of the laser radar is optimized, and the application range of the laser radar is expanded.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative, for example, in the form of flow charts and block diagrams in the figures of the accompanying drawings, showing apparatus according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module. It should also be noted that, in alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams, and combinations of blocks in the block diagrams, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In addition, each functional module or unit in each embodiment of the present invention may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the scope of the present invention.