Integrated laser radar device for denoising signals based on depolarization principle

Abstract

The invention discloses an integrated laser radar device for denoising signals based on a depolarization principle, relates to the technical field of laser radars, and aims to solve the problems that the overall detection precision is relatively low and the detection precision is relatively high due to the fact that the existing laser radar is influenced by noise signals caused by objects such as rain or fog. According to the key points of the technical scheme of the invention, the device comprises a light source device, a polarization control device, a light beam steering device, a receiving device, a polarization beam splitting device, a polarization filtering device and a signal processing device which are integrated on the same substrate, the light source device is used for generating a detection light beam. The laser radar has the advantages that noise signals caused by objects such as rain or fog can be filtered, and meanwhile, non-noise signals caused by the objects in the detection light beams and the detection area can be detected, so that the working effect of the laser radar in non-ideal weather can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar device for removing noise signals based on the depolarization principle. Background Art

[0002] LiDAR is an important equipment for high-tech civilian and military technologies such as intelligent driving and intelligent robots. Light detection and ranging (LiDAR) based on optical phased array (OPA) is a system that achieves two-dimensional light beam steering through phase and wavelength control. It can achieve the same functions as traditional radar on a chip and has the advantages of flexible steering and integration. Silicon-based LiDAR is considered to be an alternative solution to traditional LiDAR due to its low power consumption and compatibility with CMOS technology.

[0003] A multi-pixel scanning laser radar with application number CN201780033248.X, which emits illumination light from each laser radar measurement channel to the surrounding environment in different directions through a beam scanning device, and the beam scanning device also guides each amount of returned measurement light to the corresponding light detector. In some embodiments, the beam scanning device includes a scanning mirror, which is rotated in an oscillating manner around a rotation axis by an actuator according to a command signal generated by a main controller. In some embodiments, the light source and detector associated with each laser radar measurement channel move in two dimensions relative to a beam shaping optical device used to collimate the light emitted from the light source. The relative movement causes the illumination beam to scan the range of the three-dimensional environment being measured.

[0004] The above-mentioned existing technical solutions have the following defects: currently, the laser radar will be affected by noise signals caused by objects such as rain or fog, resulting in low overall detection accuracy, and other influencing factors in the external environment cannot be filtered out all day, affecting the overall normal operation. Summary of the invention

[0005] The purpose of the present invention is to provide a laser radar device based on the depolarization principle to remove noise signals by detecting the non-noise signals caused by the detection light beam and the objects in the detection area, thereby ensuring that the laser radar works in non-ideal weather conditions.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An integrated laser radar device for removing noise signals based on the depolarization principle, comprising a light source device, a polarization control device, a beam steering device, a receiving device, a polarization beam splitting device, a polarization filtering device and a signal processing device, wherein the light source device is used to generate a detection beam;

[0008] The polarization control device is used to adjust the polarization of the detection light beam;

[0009] The light beam steering device is used to emit the regulated detection light beam to the detection area;

[0010] The receiving device is used to receive the reflected light beam after the detection light beam encounters the object;

[0011] The polarization beam splitter is used to separate the light of two orthogonal polarization states in the reflected light beam;

[0012] The polarization filtering device is used to select the polarization state corresponding to the reflected light beam caused by the object in the detection area from the two polarization states obtained by the polarization beam splitting device according to the set or analyzed polarization state result of the reflected light beam caused by the object such as rain or fog;

[0013] The signal processing device is used to obtain detection area information from the reflected light beam;

[0014] The polarization control device, the polarization beam splitting device and the polarization filtering device are combined to remove reflected light beams caused by objects such as rain or fog;

[0015] The light source device, the polarization control device, the light beam steering device, the receiving device, the polarization beam splitting device, the polarization filtering device and the signal processing device are integrated on the same substrate.

[0016] Furthermore, the light source device adopts one of a fiber laser, an edge emitting laser and a surface emitting laser, the polarization control device adopts a cascaded N-stage Mach-Zehnder interferometer, where N≥2, and the polarization control device additionally adopts an adaptive algorithm to achieve a better polarization control ratio.

[0017] Furthermore, the light beam steering device adopts an optical phased array or a focal plane array, and the receiving device adopts an optical phased array or a focal plane array.

[0018] Furthermore, the polarization beam splitting device adopts a structure based on the principles of plane grating, arrayed waveguide grating, photonic crystal, Mach-Zehnder interferometer, directional coupler, multimode interference coupler, two-photon interference, quasi-imaging, or cascaded multimode interference.

[0019] Furthermore, the polarization control device, the light beam steering device and the polarization beam splitting device are designed using silicon-based materials, indium phosphide materials, lithium niobate materials or surface plasma superstructures.

[0020] Furthermore, when the polarization control device fixedly converts the detection beam into a left-handed circularly polarized detection beam or a right-handed circularly polarized detection beam, the polarization filtering device fixedly filters out the s-linear polarization state or the p-linear polarization state from the reflected beam, and the linear polarization state is determined by the polarization state of the detection beam after passing through the polarization control device.

[0021] Furthermore, when the polarization control device converts the detection beam into a detection beam of any polarization state, the polarization filtering device includes a polarization analysis device and a signal screening device.

[0022] Furthermore, when the polarization control device fixedly converts the detection beam into a left-handed circular polarization state detection beam or a right-handed circular polarization state detection beam, the left-handed circular polarization state detection beam or the right-handed circular polarization state detection beam is hardly reflected by rain or fog, and the polarization analysis device is an optional structure.

[0023] Furthermore, the polarization analysis device adopts a structure such as a polarization analyzer or a polarization camera or a polarization photodetector, and is used to infer the polarization state of the reflected light beam caused by objects such as rain or fog based on the main polarization state existing in the reflected light beam detected by the receiving device during multiple detections;

[0024] The signal screening device is used to select the polarization state corresponding to the reflected light beam caused by objects in the detection area from the two polarization states obtained by the polarization beam splitting device according to the polarization state result of the reflected light beam caused by objects such as rain or fog analyzed by the polarization analysis device.

[0025] In summary, the beneficial technical effects of the present invention are:

[0026] 1. The present invention is a laser radar device for removing noise signals based on the depolarization principle, which can remove the reflected light beam (noise signal) caused by objects such as rain or fog, and can detect the reflected light beam (non-noise signal) caused by the detection light beam and the objects in the detection area;

[0027] 2. The present invention is based on the principle of depolarization and can filter noise signals caused by objects such as rain or fog. At the same time, it can detect the non-noise signals caused by the detection light beam and objects in the detection area, thereby ensuring the operation of the lidar in non-ideal weather conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the overall structure of Embodiment 3 of the present invention;

[0030] Figure 3 It is a schematic diagram of the overall structure of the fourth embodiment of the present invention.

[0031] In the figure: 21, light source device; 22, polarization control device; 23, light beam steering device; 24, receiving device; 25, polarization beam splitting device; 26, polarization filtering device; 27, signal processing device; 261, polarization analysis device; 262, signal screening device. DETAILED DESCRIPTION

[0032] Embodiment 1

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0034] Reference Figure 1 , a laser radar device for removing noise signals based on the depolarization principle, comprising a light source device 21, a polarization control device 22, a beam steering device 23, a receiving device 24, a polarization beam splitting device 25, a polarization filtering device 26 and a signal processing device 27, wherein the light source device 21 is used to generate a detection beam;

[0035] The polarization control device 22 is used to adjust the polarization of the detection beam;

[0036] The beam steering device 23 is used to emit the regulated detection beam to the detection area;

[0037] The receiving device 24 is used to receive the reflected light beam after the detection light beam encounters the object;

[0038] The polarization beam splitter 25 is used to separate the light of two orthogonal polarization states in the reflected light beam;

[0039] The polarization filter device 26 is used to select the polarization state corresponding to the reflected light beam caused by the object in the detection area from the two polarization states obtained by the polarization beam splitter 25 according to the set or analyzed polarization state result of the reflected light beam caused by the object such as rain or fog;

[0040] The signal processing device 27 is used to obtain the detection area information from the reflected light beam;

[0041] The polarization control device 22, the polarization beam splitter 25 and the polarization filtering device 26 are combined to remove the reflected light beam caused by objects such as rain or fog. The laser radar device for removing noise signals based on the depolarization principle can remove the reflected light beam noise signal caused by objects such as rain or fog, and can also detect the reflected light beam non-noise signal caused by the detection beam and objects in the detection area.

[0042] The light source device 21 adopts one of a fiber laser, an edge emitting laser and a surface emitting laser, the polarization control device 22 adopts a cascaded N-stage Mach-Zehnder interferometer, where N≥2, and the polarization control device 22 additionally adopts an adaptive algorithm to achieve a better polarization control ratio.

[0043] The light beam steering device 23 adopts an optical phased array or a focal plane array, and the receiving device 24 adopts an optical phased array or a focal plane array.

[0044] The polarization beam splitter 25 adopts a structure based on the principles of plane grating, arrayed waveguide grating, photonic crystal, Mach-Zehnder interferometer, directional coupler, multimode interference coupler, two-photon interference, quasi-imaging, or cascaded multimode interference.

[0045] The polarization control device 22, the beam steering device 23 and the polarization beam splitting device 25 are designed with silicon-based materials, indium phosphide materials, lithium niobate materials or surface plasma superstructures, and can detect the non-noise signals caused by the light beam and objects in the detection area, thereby ensuring the operation of the laser radar in non-ideal weather conditions.

[0046] Embodiment 2

[0047] In a possible laser radar device for removing noise signals based on the depolarization principle, when the polarization control device 22 fixedly converts the detection beam into a left-handed circularly polarized detection beam or a right-handed circularly polarized detection beam, the polarization filtering device 26 fixedly filters out the s-linear polarization state or the p-linear polarization state from the reflected beam, and the linear polarization state is determined by the polarization state of the detection beam after passing through the polarization control device 22. When the polarization control device 22 fixedly converts the detection beam into a left-handed circularly polarized detection beam or a right-handed circularly polarized detection beam, the left-handed circularly polarized detection beam or the right-handed circularly polarized detection beam is hardly reflected by rain or fog, and the polarization analysis device 261 is an optional structure.

[0048] Embodiment 3

[0049] In a possible laser radar device for removing noise signals based on the depolarization principle, when the polarization control device 22 converts the detection beam into a detection beam of any polarization state, the polarization filtering device 26 includes a polarization analysis device 261 and a signal screening device 262.

[0050] The polarization analysis device 261 adopts a structure such as a polarization analyzer or a polarization camera or a polarization photodetector, and is used to infer the polarization state of the reflected light beam caused by objects such as rain or fog based on the main polarization states existing in the reflected light beam detected by the receiving device 24 during multiple detections;

[0051] The signal screening device 262 is used to select the polarization state corresponding to the reflected light beam caused by objects in the detection area from the two polarization states obtained by the polarization beam splitting device 25 according to the polarization state result of the reflected light beam caused by objects such as rain or fog analyzed by the polarization analysis device 261.

[0052] Embodiment 4

[0053] A possible laser radar device for removing noise signals based on the depolarization principle includes a light source device 21, a beam steering device 23, a receiving device 24, a polarization beam splitting device 25, a polarization analysis device 261, a signal screening device 262, a polarization filtering device 26 and a signal processing device 27. At this time, the detection beam does not need to be adjusted.

[0054] Working principle: First, the light source device 21 is used to generate a detection beam. After the polarization of the detection beam is adjusted by the polarization control device 22, the beam steering device 23 emits the adjusted detection beam to the detection area. At the same time, the polarization beam splitter 25 separates the two orthogonal polarization states of light in the reflected beam. At this time, the polarization filter 26 selects the polarization state corresponding to the reflected beam (non-noise signal) caused by objects in the detection area from the two polarization states obtained by the polarization beam splitter 25 according to the set or analyzed polarization state result of the reflected beam (noise signal) caused by objects such as rain or fog. Finally, the signal processing device 27 obtains the detection area information from the reflected beam. The overall function of removing the reflected beam (noise signal) caused by objects such as rain or fog can be achieved through the combination of the polarization control device 22, the polarization beam splitter 25 and the polarization filter 26.

[0055] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, all equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated laser radar device for removing noise signals based on the depolarization principle, comprising a light source device (21), a polarization control device (22), a beam steering device (23), a receiving device (24), a polarization beam splitting device (25), a polarization filtering device (26) and a signal processing device (27), characterized in that: The light source device (21) is used to generate a detection light beam; The polarization control device (22) is used to adjust the polarization of the detection light beam; The light beam steering device (23) is used to emit the regulated detection light beam to the detection area; The receiving device (24) is used to receive the reflected light beam after the detection light beam encounters the object; The polarization beam splitting device (25) is used to separate light of two orthogonal polarization states in the reflected light beam; The polarization filtering device (26) is used to select the polarization state corresponding to the reflected light beam caused by the object in the detection area from the two polarization states obtained by the polarization beam splitting device (25) according to the set or analyzed polarization state result of the reflected light beam caused by the object such as rain or fog; The signal processing device (27) is used to obtain detection area information from the reflected light beam; The polarization control device (22), the polarization beam splitting device (25) and the polarization filtering device (26) are combined to remove reflected light beams caused by objects such as rain or fog. The light source device (21), the polarization control device (22), the light beam steering device (23), the receiving device (24), the polarization beam splitting device (25), the polarization filtering device (26) and the signal processing device (27) are integrated on the same substrate.

2. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 1, characterized in that: The light source device (21) adopts one of a fiber laser, an edge-emitting laser and a surface-emitting laser, the polarization control device (22) adopts a cascaded N-stage Mach-Zehnder interferometer, wherein N≥2, and the polarization control device (22) additionally adopts an adaptive algorithm to achieve a better polarization control ratio.

3. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 1, characterized in that: The light beam steering device (23) adopts an optical phased array or a focal plane array, and the receiving device (24) adopts an optical phased array or a focal plane array.

4. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 1, characterized in that: The polarization beam splitting device (25) adopts a structure based on the principles of plane grating, array waveguide grating, photonic crystal, Mach-Zehnder interferometer, directional coupler, multimode interference coupler, two-photon interference, quasi-imaging, or cascade multimode interference.

5. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 1, characterized in that: The polarization control device (22), the light beam steering device (23) and the polarization beam splitting device (25) are designed using silicon-based materials, indium phosphide materials, lithium niobate materials or surface plasma superstructures.

6. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 1, characterized in that: When the polarization control device (22) fixedly converts the detection beam into a left-handed circularly polarized detection beam or a right-handed circularly polarized detection beam, the polarization filtering device (26) fixedly filters out an s-linear polarization state or a p-linear polarization state from the reflected beam, and the linear polarization state is determined by the polarization state of the detection beam after passing through the polarization control device (22).

7. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 1, characterized in that: When the polarization control device (22) converts the detection light beam into a detection light beam in any polarization state, the polarization filtering device (26) internally comprises a polarization analysis device (261) and a signal screening device (262).

8. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 6, characterized in that: When the polarization control device (22) fixedly converts the detection beam into a left-handed circular polarization state detection beam or a right-handed circular polarization state detection beam, the left-handed circular polarization state detection beam or the right-handed circular polarization state detection beam is hardly reflected by rain or fog, and the polarization analysis device (261) is an optional structure.

9. The integrated laser radar device for removing noise signals based on the depolarization principle according to claim 8, characterized in that: The polarization analysis device (261) adopts a structure such as a polarization analyzer or a polarization camera or a polarization photodetector, and is used to infer the polarization state of the reflected light beam caused by objects such as rain or fog based on the main polarization state existing in the reflected light beam detected by the receiving device during multiple detections; The signal screening device (262) is used to select the polarization state corresponding to the reflected light beam caused by an object in the detection area from the two polarization states obtained by the polarization beam splitting device (25) based on the polarization state result of the reflected light beam caused by an object such as rain or fog analyzed by the polarization analysis device (261).

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