CN117970368A

CN117970368A - Lidar system and vehicle

Info

Publication number: CN117970368A
Application number: CN202211309221.8A
Authority: CN
Inventors: 田卓承; 杨祥辉; 张乃川; 石拓
Original assignee: Zvision Technologies Co Ltd
Current assignee: Zvision Technologies Co Ltd
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2024-05-03

Abstract

The present disclosure provides a non-coaxial lidar system and a vehicle. The laser radar system includes: a supercontinuum laser emitting a laser beam of a broad spectral range; a beam-splitting unit receiving the laser beam from the supercontinuum laser, dispersing the laser beam into a plurality of sub-laser beams having different wavelength ranges, and emitting each sub-laser beam in a corresponding beam-splitting direction; a scanning unit that receives the plurality of sub-laser beams from the beam splitting unit and emits each sub-laser beam in a predetermined emission direction, the scanning unit being capable of changing the emission direction of each sub-laser beam so that each sub-laser beam is scanned in at least one scanning direction; a light receiving unit detecting a reflected beam, which is a sub-laser beam reflected by the target object; and a control unit that controls the supercontinuum laser, the scanning unit, and the light receiving unit, and detects the target object from the reflected beam received by the light receiving unit.

Description

Lidar system and vehicle

Technical Field

The present disclosure relates to lidar systems, and more particularly to lidar systems and vehicles.

Background

LiDAR systems, also known as laser detection and ranging (LiDAR) systems, measure information, such as the position, velocity, etc., of a target object, such as a vehicle and a pedestrian, by transmitting a laser beam to the target object and receiving the beam reflected or scattered back from the target object. In order to better meet the safety driving requirement of the vehicle, the perception capability and detection range of the vehicle-mounted laser radar to the surrounding environment need to be enhanced. In a vehicle-mounted laser radar, the detection view field range of a single laser light source is limited, a plurality of laser light sources with different angles are usually required to be arranged to emit and receive reflected light at the same time, and then the view fields of the plurality of laser light sources are spliced to achieve the effect of expanding the view field. The fiber laser has high output power and good beam quality, and is an ideal choice for long-distance laser radar systems, but the fiber laser has relatively larger volume and higher cost. If a plurality of fiber lasers are adopted for splicing the view fields so as to meet the requirement of the detection range, the volume and the cost of the laser radar are obviously increased.

Therefore, it is necessary to consider increasing the detection field of view range of a single laser light source, thereby reducing the volume and cost of the lidar system.

Disclosure of Invention

In order to address at least some of the above-described drawbacks of current lidar systems, the present disclosure provides a lidar system, as well as a vehicle and an electronic device in which the lidar system is installed.

One aspect of the present disclosure relates to a laser radar system, comprising: a supercontinuum laser configured to emit a laser beam of a broad spectral range; a beam splitting unit configured to receive the laser beam from the supercontinuum laser, disperse the laser beam into a plurality of sub-laser beams having different wavelength ranges, and emit each sub-laser beam in a corresponding beam splitting direction; a scanning unit configured to receive the plurality of sub-laser beams from the beam splitting unit and emit each sub-laser beam in a predetermined emission direction, the scanning unit being configured to be able to change the emission direction of each sub-laser beam so that each sub-laser beam is scanned in at least one scanning direction; a light receiving unit configured to detect a reflected beam, which is the sub-laser beam reflected by a target object; and a control unit configured to control the supercontinuum laser, the scanning unit, and the light receiving unit, and detect the target object from the reflected beam received by the light receiving unit.

Another aspect of the present disclosure relates to a vehicle. The vehicle includes a lidar system and a vehicle control unit. The vehicle control unit is communicatively coupled with the lidar system. The vehicle control unit is configured to control operation of a control unit of the lidar system.

Drawings

The foregoing and other objects and advantages of the disclosure are further described below in connection with the following detailed description of the embodiments, with reference to the accompanying drawings. In the drawings, the same or corresponding technical features or components will be denoted by the same or corresponding reference numerals.

FIG. 1 shows a schematic composition diagram of a lidar system according to an embodiment of the disclosure;

FIG. 2 shows a schematic diagram of a configuration of a supercontinuum laser in accordance with embodiments of the present disclosure;

Fig. 3 shows a schematic diagram of the configuration of a spectroscopic unit according to an embodiment of the present disclosure;

Fig. 4 shows a schematic view of another configuration of a spectroscopic unit according to an embodiment of the present disclosure;

FIG. 5 shows a schematic diagram of an emitted beam of a lidar system according to an embodiment of the present disclosure;

FIG. 6 illustrates a schematic diagram of the operation of a lidar system according to an embodiment of the present disclosure;

FIG. 7 illustrates a schematic diagram of another operating scenario of a lidar system according to an embodiment of the present disclosure; and

Fig. 8 shows a schematic composition of a vehicle incorporating a lidar system according to an embodiment of the disclosure.

Detailed Description

The following detailed description is made with reference to the accompanying drawings and is provided to assist in a comprehensive understanding of various example embodiments of the disclosure. The following description includes various details to aid in understanding, but these are to be considered merely examples and are not intended to limit the disclosure, which is defined by the appended claims and their equivalents. The words and phrases used in the following description are only intended to provide a clear and consistent understanding of the present disclosure. In addition, descriptions of well-known structures, functions and configurations may be omitted for clarity and conciseness. Those of ordinary skill in the art will recognize that various changes and modifications of the examples described herein can be made without departing from the scope of the disclosure.

Fig. 1 illustrates an exemplary lidar system 100 to which the techniques of the present disclosure may be applied. The lidar system 100 may include a supercontinuum laser 102, a spectroscopic unit 103, a scanning unit 104, a light receiving unit 106, and a control unit 108.

The supercontinuum laser 102 emits a broad spectral range laser beam for scanning the target object 120. The supercontinuum laser 102 may be a nonlinear amplified supercontinuum fiber laser or a PCF supercontinuum fiber laser. The supercontinuum laser 102 may emit light in different forms, such as pulsed light. The spectrum range of the supercontinuum laser can be 900-2300 nm, 400-2400 nm, etc. In one or more embodiments, the supercontinuum laser 102 may further include an optical component optically coupled to the supercontinuum laser 102 for collimating, focusing, filtering, or polarization modulating the light beam emitted by the supercontinuum laser 102.

Fig. 2 shows a schematic diagram of a configuration of a supercontinuum laser according to an embodiment of the present disclosure. As shown in fig. 2, the supercontinuum laser 102 comprises a seed source 201, a pump source 202, a linear amplifier 203, and a nonlinear spectral broadening module 204. The seed source 201 outputs a pulse seed signal, the pump source 202 provides energy for the linear amplifier 203 to amplify the output power of the seed signal, and the amplified pulse signal is coupled into the nonlinear spectrum widening module 204. In the nonlinear spectrum stretching module 204, the spectrum of the pulse signal is stretched in a very large range under the action of various nonlinear effects, and finally a spectrum with ultra-wide coverage range, namely a supercontinuum, is output. For example, the seed signal provided by the seed source 201 is a spike at a center wavelength of 1064 nm. The seed signal becomes a spike with a greater intensity at the center wavelength of 1064nm after amplification by the linear amplifier 203. The amplified spike signal is then passed through a nonlinear spectral broadening module 204 to a broad range of supercontinuum signals that can be of sufficient intensity over a wavelength range of, for example, 500nm to 2000 nm.

For supercontinuum fiber lasers, there are two approaches to the nonlinear spectral broadening module 204. One solution is to select a Photonic Crystal Fiber (PCF) with a high nonlinear coefficient, i.e., a PCF supercontinuum fiber laser. In this laser, a linear fiber amplifier amplifies the seed signal to a higher power before it is coupled to the PCF. In the process of signal spectrum propagation in PCF, the spectrum is widened in a large range under the action of non-linear effects such as stimulated Raman scattering, four-wave mixing, scattered wave, soliton and the like, so that the visible and near infrared bands of 400-2300 nm can be covered. Another approach to the nonlinear spectral broadening module 204 is to employ a high power nonlinear fiber amplifier, i.e., a nonlinear amplified supercontinuum fiber laser. In this laser, a linear fiber amplifier amplifies the seed signal to a higher power and then couples it to a high power fiber amplifier. By means of extending the length of the optical fiber in the high power optical fiber amplifier, the nonlinear accumulation of the signal light transmitted in the amplifier is raised to become one nonlinear optical fiber amplifier. In the nonlinear optical fiber amplifier, when the power of the signal light is amplified to a threshold value at which a certain nonlinear effect occurs, the signal spectrum begins to broaden under the effect of the nonlinear effect. The power amplification and the spectral process of the signal light are performed simultaneously with the transmission of the pulses in the nonlinear fiber amplifier. In embodiments of the present disclosure, the supercontinuum laser 102 may produce near infrared supercontinuum with a spectral coverage in the 900-2300 nm range.

The specific choice of which supercontinuum generation scheme can be selected preferentially according to the actual requirements of the laser radar, such as the detection wavelength range, the output power requirement, the type of a detector used by a receiving system and the like.

Returning to fig. 1, as shown, the spectroscopic unit 103 receives a laser beam of a broad spectral range from the supercontinuum laser 102. After that, the light splitting unit 103 disperses the received laser beam into a plurality of sub-laser beams having different wavelength ranges and emits each sub-laser beam in a corresponding light splitting direction.

Fig. 3 shows a schematic diagram of the configuration of a spectroscopic unit according to an embodiment of the present disclosure. The light splitting unit 103 includes a light splitting device 301 and a plurality of light guiding devices 302. The broad spectral range laser beam from supercontinuum laser 102 may be composed of multiple components with different wavelength ranges. As shown in fig. 3, the laser beam has a plurality of components in a wavelength range lambda ₁、λ₂、λ₃、……λ_n, where n is an integer greater than 1. In this example, the wavelengths of the laser components of the respective wavelength ranges sequentially increase from the wavelength range λ ₁ to the wavelength range λ _n. In a laser beam of a broad spectral range, the individual components spatially overlap each other and propagate in the same direction. The laser beam of a wide spectral range from the supercontinuum laser 102 is transmitted into the spectroscopic unit 103 and enters the spectroscopic device 301. The spectroscopic device 301 is configured to disperse the laser beam in space in terms of wavelength. In one embodiment of the present disclosure, the light splitting device 301 may be, for example, a light splitting prism. The beam splitting prism can enable the transmission directions of the laser beams with different wavelengths to deflect differently and emit the laser beams along different angles by utilizing the difference of refractive indexes of the laser beams with different wavelengths in the beam splitting prism, so that the laser beams are dispersed in space according to the wavelengths. As shown in fig. 3, the laser beams passing through the beam splitting prism are spatially dispersed in the wavelength order (from the wavelength range λ ₁ to the wavelength range λ _n). In another embodiment of the present disclosure, the light splitting device 301 may be, for example, a light splitting grating. By utilizing diffraction of laser beams with different wavelengths at the beam splitting grating, the beam splitting grating can enable diffraction waves of the laser beams with different wavelengths to face different directions and emit along different angles, so that the laser beams are dispersed in space according to the wavelengths. By the spectroscopic grating, an effect similar to that of the spectroscopic prism shown in fig. 3 can be obtained.

The laser light dispersed through the light-splitting device 301 is received by a plurality of light-guiding devices 302. Each of the plurality of light guide devices 302 is configured to couple a sub-laser beam having a corresponding wavelength range therein and guide the sub-laser beam to emit the sub-laser beam in a respective splitting direction, respectively. As shown in fig. 3, in one embodiment of the present disclosure, the spectroscopic device 301 includes n light guide devices 302, and each light guide device 302 corresponds to one sub-laser beam. Each light guide 302 includes a microlens 303, a transmission fiber 304, and a collimator 305. The microlens 303 is positioned in the laser beam dispersed in space by the spectroscopic device 301 and configured to couple sub-laser beams having a wavelength range corresponding to the light guide device 302 into the light guide device. For convenience of description, the wavelength ranges of the sub-laser beams are used hereinafter to represent the corresponding sub-laser beams. That is, the sub-laser beam of the wavelength range λ ₁ is described as a sub-laser beam λ ₁. For example, the microlens 303-1 of the light guide 302-1 is positioned at a position corresponding to the sub-laser beam of the wavelength range λ ₁, and couples the sub-laser beam of the wavelength range λ ₁ into the light guide 302-1. Similar to sub-laser beam lambda ₁, microlens 303-2 of light guide 302-2 is positioned at a position corresponding to sub-laser beam lambda ₂ of wavelength range lambda ₂ and couples sub-laser beam lambda ₂ of wavelength range lambda ₂ into light guide 302-2. The transmission fiber 304 is coupled to the micro lens 303 and guides the sub laser beams. For example, transmission fiber 304-1 is coupled to microlens 303-1 and directs sub-laser beam lambda ₁. The collimator 305 is coupled to the transmission fiber 304 and is configured to collimate the sub-laser beams and emit them in respective splitting directions. For example, collimator 305-1 is coupled to transmission fiber 304-1 and is configured to collimate sub-laser beam lambda ₁ and emit in a corresponding splitting direction. The micro-lenses 303, transmission fibers 304 and collimators 305 may be coupled together by means of, for example, fusion splicing.

In the embodiment of the present disclosure, by adjusting the direction in which the light guide device 302 emits the sub-laser beams, it is possible to achieve that the sub-laser beams in different wavelength ranges are emitted at arbitrary spectroscopic angles. For example, as shown in fig. 3, the light guide device 302-1 may emit the sub-laser beams λ ₁ of the wavelength range λ ₁ in an upward oblique direction, and the light guide devices 302-2 to 302-n may emit the sub-laser beams λ ₂ to λ _n of the wavelength ranges λ ₂ to λ _n in a horizontal parallel direction. Further, it will be understood by those skilled in the art that only one specific example is shown in fig. 3, and the direction in which each light guide device 302 emits the sub-laser beam may be arbitrarily set, so that the light guide devices 302-1 to 302-n may emit the sub-laser beams of the corresponding wavelength ranges in predetermined spectroscopic directions as needed.

Fig. 4 shows a schematic diagram of another configuration of a spectroscopic unit according to an embodiment of the present disclosure. The spectroscopic unit shown in fig. 4 has a similar structure to the spectroscopic unit shown in fig. 3, and thus the same portions of both are not described repeatedly. The difference between the spectroscopic unit of fig. 3 and fig. 4 is that the wavelength distribution of the laser beam in space is changed by the configuration of the light guide device in fig. 4. As shown in fig. 4, the light-splitting device 401 disperses the laser beam in the space in a first wavelength distribution, that is, in the order of increasing wavelength from top to bottom (from the wavelength range λ ₁ to the wavelength range λ _n). After that, the laser light dispersed through the light-splitting device 401 is received by the plurality of light-guiding devices 402. The light guide device 402 in fig. 4 is similar in structure to the light guide device 302 in fig. 3, and includes a microlens 403, a transmission fiber 404, and a collimator 405. But with respect to the light guide devices 402 shown in fig. 4, the laser beam is emitted in a second wavelength distribution by providing a configuration of each light guide device 402 (specifically, a configuration of the transmission optical fiber 404). As shown in fig. 4, the transmission fiber 404 of the light guide device 402-1 receiving the sub-laser beam of the wavelength range λ ₁ is moved to the lowermost so as to emit the sub-laser beam of the wavelength range λ ₁ from the lowermost in the second wavelength distribution. It can be seen that the first wavelength distribution in space of the laser beam generated by the light splitting device is different from the second wavelength distribution in space of the laser beam generated by the light guiding device.

Those skilled in the art will appreciate that other light guide devices may be provided accordingly to arbitrarily change the wavelength distribution of the laser beam in space as desired.

Thus, by configuring the light guide device, for example, it is possible to move the sub-laser beam having a longer wavelength range to the middle region of the wavelength distribution of the laser beam in space, and to move the sub-laser beam having a shorter wavelength range to both sides of the wavelength distribution. In this embodiment, for example, the distribution of the wavelength bands that are more dangerous to the human eye can be adjusted to facilitate the human eye safety protection. In addition, for example, the distribution of the wave bands with high penetrability can be adjusted, so that the distance measurement distance can be improved.

Returning to fig. 1, as shown, the scanning unit 104 is configured to receive a plurality of sub-laser beams from the beam splitting unit 103 and emit each sub-laser beam in a predetermined emission direction.

In the embodiments of the present disclosure, by adjusting the beam splitting unit, the emission directions of a plurality of sub-laser beams simultaneously generated by one laser beam of a wide spectral range can be made to be in the same emission plane, i.e., a plurality of sub-laser beams having different emission directions are all located in one plane. Thus, embodiments of the present disclosure are capable of making measurements of a target object within the emission plane, thereby expanding the field of view of the lidar system.

Fig. 5 shows a schematic diagram of an emitted beam of a lidar system according to an embodiment of the present disclosure. As shown in fig. 5, the sub-laser beams λ ₁ to λ _n of the wavelength ranges λ ₁ to λ _n by the laser radar system 100 lie in the same emission plane S ₁, and the emission plane S ₁ is a vertical plane perpendicular to the horizontal plane. Thus, measurements can be made of the target object within the emission plane S ₁.

Thus, by the spatial distribution of each sub-laser beam simultaneously generated by one laser beam of a wide spectral range, detection can be performed within the spatial distribution of the sub-laser beams, thereby realizing scanning detection of the target object.

On the basis of this, the scanning unit 104 is further configured to be able to change the emission direction of each sub-laser beam so that each sub-laser beam is scanned in at least one scanning direction.

The scanning unit 104 may be any number of optical mirrors driven by any number of drivers that can be driven to change their orientation to change the direction of the reflected beam of the light beam impinging on the optical mirrors. For example, the scanning unit 104 may include a planar mirror, a prism, a polarization grating, a microelectromechanical system (MEMS) galvanometer, and the like. For MEMS galvanometers, the mirror surface is rotated or translated in one or two dimensions under electrostatic/piezoelectric/electromagnetic actuation. Under drive of the driver, the scanning unit 104 directs the beam from the supercontinuum laser 102 to various locations within the field of view to effect scanning of the target object 120 within the field of view.

In an embodiment of the present disclosure, the scanning unit 104 is configured such that the emission directions of the plurality of sub-laser beams are maintained in the same emission plane and the emission plane is maintained perpendicular to the scanning direction of each sub-laser beam during the scanning of the plurality of sub-laser beams. In one embodiment of the present disclosure, the beam splitting direction of the sub laser beam supplied from the beam splitting unit may be configured to be already in one plane. For example, by adjusting the light guide device 302 (e.g., collimator 305) of the spectroscopic unit 103, the spectroscopic directions of the sub-laser beams can be made to lie in one plane. In this case, the scanning unit 104 may be a single optical mirror or the same scanning pattern may be employed for each sub-laser beam such that the emission directions of the sub-laser beams emitted from the scanning unit 104 remain in the same emission plane. In another embodiment of the present disclosure, the beam splitting directions of the sub laser beams provided from the beam splitting unit may not be in one plane. In this case, the scanning unit 104 may employ a different scanning mode for each sub-laser beam, and the emission directions of the sub-laser beams emitted from the scanning unit 104 are kept within the same emission plane.

As shown in fig. 5, the sub-laser beams λ _i、λ_j、λ_k among the sub-laser beams λ ₂ to λ _n are exemplified. In this example, the scanning direction of the sub-laser beam λ _i is d _i, the scanning direction of the sub-laser beam λ _j is d _j, and the scanning direction of the sub-laser beam λ _k is d _k. The emission plane S ₁ of the sub-laser beam is a vertical plane, and the scanning directions d _i、d_j and d _k are both horizontal directions. During the scanning of the plurality of sub-laser beams by the scanning unit 104, the emission directions of the sub-laser beams λ ₁ to λ _n are kept in the same emission plane, and the emission plane is kept perpendicular to the scanning direction of each sub-laser beam. That is, as a whole, the emission plane S ₁ of the sub-laser beam emitted by the lidar system is scanned in the horizontal direction.

Thus, by providing scanning in another dimension different from the distribution dimension of the sub-laser beams by the scanning unit, the detection range of the lidar system can be further increased. For example, in the case where the emission directions of a plurality of sub laser beams are in the same emission plane as shown in fig. 5, at least two-dimensional scanning can be provided by providing scanning in one scanning direction. Thereby, two-dimensional scanning detection of the target object can be achieved.

Further, it is apparent to those skilled in the art that the scanning unit may arbitrarily set the scanning mode of the plurality of sub-laser beams as needed, and that the emission directions of the plurality of sub-laser beams may not be in the same emission plane and may be scanned in different scanning modes during the scanning. Thus, embodiments of the present disclosure may also increase the design flexibility of a lidar system, accommodating more operating scenarios.

Referring back to fig. 1, in one or more embodiments, lidar system 100 may also include a transmit lens 110. The emission lens 110 may be used to expand the beam emitted by the supercontinuum laser 102 and diverted by the scanning unit 104. The emission lens 110 may include a Diffractive Optical Element (DOE) for shaping, separating, or diffusing the light beam. The emission lens 110 may be present alone or may be integrated into other components, such as the scanning unit 104 or the supercontinuum laser 102. The position of the emission lens 110 in the emission light path from the supercontinuum laser 102 to the target object is not limited to that shown in fig. 1, but may be changed to other positions. For example, an emission lens may be disposed between the supercontinuum laser 102 and the scanning unit 104 such that the beam emitted by the supercontinuum laser 102 is first expanded by the emission lens and then diverted by the scanning unit.

With continued reference to fig. 1, in one or more embodiments, lidar system 100 may also include a light-receiving unit 106. The light receiving unit 106 is configured to detect reflected beams, which are the sub-laser beams reflected by the target object.

After the light beam is reflected from the target object 120, a portion of the reflected light (or referred to as an echo signal) returns to the lidar system 100 and is received by the light-receiving unit 106. The light receiving unit 106 receives and detects a portion of the reflected light from the target object 120 and generates a corresponding electrical signal. The target object may be any object within the scanning field of view of the lidar that is capable of reflecting the scanning laser light, such as a vehicle, a pedestrian, an animal, a guideboard, an obstacle, a tree, a shelf, furniture, etc. The light receiving unit 106 may include a receiving device and associated receiving circuitry. Each receiving circuit may be configured to process the output electrical signal of a corresponding receiving device. The receiving device comprises various forms of photodetectors or one-dimensional or two-dimensional arrays of photodetectors, and accordingly the receiving circuit may be a circuit or an array of circuits. The photodetector measures the power, phase or time characteristics of the reflected light and produces a corresponding current output. The photodetector may be an avalanche diode (APD), single Photon Avalanche Diode (SPAD), PN photodiode, or PIN photodiode.

In an embodiment of the present disclosure, the receiving device of the receiving unit 106 is further configured to detect a wavelength range of the reflected light. For example, the receiving device may include a beam splitting device and a detector array. Thus, the lidar system of embodiments of the present disclosure may implement a wavelength detection function to identify a target object from a spectral dimension.

With continued reference to fig. 1, in one or more embodiments, lidar system 100 may also include a control unit 108. The control unit 108 is configured to control the supercontinuum laser 102, the scanning unit 104, and the light receiving unit 106, and detect a target object from the reflected beam received by the light receiving unit 106.

The control unit 108 is communicatively coupled to one or more of the supercontinuum laser 102, the scanning unit 104, and the light receiving unit 106. The control unit 108 may control whether and when the supercontinuum laser 102 emits a light beam and may also control the wavelength of the laser beam emitted by the supercontinuum laser 102. The control unit 108 may control the scanning unit 104 to scan the light beam to a specific position. The control unit 108 may process and analyze the electrical signals output by the light receiving unit to finally determine the position, speed, etc. characteristics of the target object 120. The control unit 108 may include an Integrated Circuit (IC), an Application Specific Integrated Circuit (ASIC), a microchip, a micro control unit, a central processing unit (cpu), a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or other circuit suitable for executing instructions or performing logic operations. The instructions executed by the control unit 108 may be preloaded into an integrated or separate memory (not shown). The memory may store configuration data or commands for the supercontinuum laser 102, the scanning unit 104, or the light receiving unit 106. The memory may also store the electric signal output from the light receiving unit 106 or the analysis result based on the output electric signal. The memory may include Random Access Memory (RAM), read Only Memory (ROM), hard disk, optical disk, magnetic disk, flash memory or other volatile or non-volatile memory, and the like. The control unit 108 may include a single or multiple processing circuits. In the case of multiple processing circuits, the processing circuits may have the same or different configurations and may interact or cooperate with each other electrically, magnetically, optically, acoustically, mechanically, etc.

After detecting the reflected light, the control unit 108 of the lidar system may calculate the distance of the target object from the time of flight, calculate the reflectivity of the target object from the intensity and the distance of the reflected light, and calculate the spatial position of the target object from the deflection position/deflection angle of the scanning unit when the scanning beam is emitted, thereby obtaining a three-dimensional measurement result of the target object. Thus, information such as the distance, speed, geometry, etc. of the target can be calculated. Further, the control unit 108 of the lidar system may acquire the wavelength range of the reflected light from the light-receiving unit 106, thereby obtaining spectral information of the reflected light.

With continued reference to fig. 1, in one or more embodiments, lidar system 100 may also include a receive lens 112 and an aperture 113. The receiving lens 112 and the diaphragm 113 are located before the light receiving unit 106 on the receiving path of the emitted light from the target object 120 to the light receiving unit 106. The receiving lens 112 may include an imaging system lens such that the focal point of the reflected beam is either in front of or behind the detection surface of the photodetector or photodetector array or is located directly above the detection surface. In some cases, instead of being present as a separate component, the receiving lens 112 may also be integrated into the light receiving unit 106. The aperture 113 is used to limit the angle of incident light incident on the light receiving unit 106, block stray light, and the like.

With continued reference to fig. 1, in one or more embodiments, lidar system 100 may further include a housing 114 for enclosing one or more of the foregoing components therein for protection. In some embodiments, the housing 114 is an opaque material, and a transparent area or window 116 may be provided in the housing 114 to allow the emitted or reflected light beam to pass through. In other embodiments, the housing 114 itself is a transparent material, thereby allowing the emitted or reflected light beam to pass through any location.

Through the description of the embodiments of the present disclosure above, by configuring the beam splitting unit, the beam splitting direction of each sub-laser beam can be flexibly set, thereby further flexibly adjusting the emission direction of each sub-laser beam. Thus, it is advantageous to expand the field of view of the lidar system.

Further, by providing a scanning unit and providing at least one scanning direction of the scanning, the lidar system may achieve scanning of the two-dimensional sub-laser beam and detection of the two-dimensional target object by providing at least one dimension of scanning in combination with the sub-laser beam dispersed by the spectroscopic unit. Therefore, the scanning scheme can be simplified, the reliability of the scanning unit and the laser radar system is improved, and the cost of the laser radar is saved.

In addition, since a supercontinuum laser is used and a laser beam of a wide spectral range is provided, a single laser emission source can be used to realize multi-wavelength detection. Therefore, the target can be identified from the spectrum dimension, which is beneficial to saving the cost of the laser radar.

In the use scenario of a lidar system, a person's eyes may be exposed to the ranging laser beam of the lidar. For example, with a lidar system mounted to a vehicle, pedestrians on the roadside or persons in a vehicle traveling in opposite directions may be irradiated with a ranging laser of the lidar system. The human eye irradiated by the ranging laser may be injured, and thus there is a safety hazard in the use of the lidar system. Accordingly, problems regarding human eye safety are receiving increasing attention in the field of lidar.

Fig. 6 shows a schematic diagram of the operation of a lidar system according to an embodiment of the present disclosure. The lidar system 100 shown in fig. 6 is mounted above the front windshield of a vehicle 500. The plurality of sub-laser beams emitted from the lidar system 100 has the case shown in fig. 5, that is, the sub-laser beams λ ₁ to λ _n are located in the same emission plane S ₁, and the emission plane S ₁ is a vertical plane perpendicular to the horizontal plane and is scanned in the horizontal direction.

In this embodiment, the emission directions of the plurality of sub-laser beams are configured such that the scanning range of the sub-laser beams including the human eye safety hazard band is out of the human eye height range. It will be appreciated by those skilled in the art that the eye safety hazard band depends on the wavelength of the laser, the power of the laser, and the time of irradiation by the laser. For lidar systems for use in vehicles, the eye-safe hazard band may be considered to be 400nm to 900nm in combination with the general arrangement of the lidar system for vehicles. That is, there may be a high risk of eye injury by the pedestrian being irradiated with laser light in the 400nm to 900nm band emitted by the lidar system mounted on the vehicle. It is apparent to those skilled in the art that the eye-safe dangerous band is a band in which the eye-safe limit is low, which is determined in consideration of the power of the sub-laser beam and the emission duration of the sub-laser beam, and the eye-safe dangerous band may be arbitrarily set as required according to the actual situation of the lidar system.

In this embodiment, it is assumed that pedestrians P ₁ and P ₂ are in front of the vehicle 600, where pedestrian P ₁ is an adult and pedestrian P ₂ is a child. In this embodiment, since the lidar system 100 is mounted above the front windshield of the vehicle 500, it may be assumed in this embodiment that the height H of the lidar system 100 from the ground is between about 1.4 meters and 1.7 meters, depending on the general height range of a normal vehicle. Furthermore, depending on the height of the average adult and child, it may be assumed in this embodiment that the eye height of adult P ₁ is between 1.4 meters and 1.9 meters, while the eye height of child P ₂ is at a minimum 0.8 meters. In addition, considering the distance between the vehicle and the pedestrian when traveling on the road and the configuration of the vehicle, it is assumed that the distance D between the pedestrians P ₁ and P ₂ and the lidar system 100 mounted on the vehicle 500 is 3 meters or more.

As shown in fig. 6, it can be determined by calculation that the emission direction of the highest sub-laser beam capable of irradiating the pedestrian P ₁ (adult) is above the horizontal plane and has an angle of about 10 ° with the horizontal plane, and that the emission direction of the lowest sub-laser beam capable of irradiating the pedestrian P ₂ (child) is below the horizontal plane and has an angle of about 10 ° with the horizontal plane. Therefore, in this embodiment, the emission direction of the sub-laser beam of the human eye safety hazard band forms an angle of 10 ° or more with the horizontal plane. For example, the emission direction of the sub-laser beams of the eye safety hazard band may be below the horizontal plane and at an angle of 10 ° to 90 ° to the horizontal plane and/or above the horizontal plane and at an angle of 10 ° to 90 ° to the horizontal plane.

Furthermore, the sub-laser beam of the eye-safe dangerous band may be provided only in one of below the water level and above the water level, and the sub-laser beam of the eye-safe dangerous band may not be provided in the other. Thereby, the risk of generating an injury to the human eye in a range of sub-laser beams that do not provide a human eye safety hazard band can be completely avoided.

In another embodiment of the present application, in order to more reliably ensure that the sub-laser beams of the eye safety hazard band emitted by the laser radar system 100 do not impinge on the human eye, the emission directions of the plurality of sub-laser beams may be configured such that the scanning range of the sub-laser beams including the eye safety hazard band is below the height of the knee of the adult, for example. In this example, it may be assumed that the adult knee height is between 0.45 meters and 0.55 meters. In this case, the emission directions of the plurality of sub-laser beams may be configured such that the emission direction of the lowest sub-laser beam including the human eye safety hazard band is below the horizontal plane and the angle with the horizontal plane is 20 ° or more, for example. Similarly, the emission direction of the highest sub-laser beam including the eye safety hazard band may be made above the horizontal plane and at an angle of 20 ° or more to the horizontal plane.

In addition, the minimum value of the angle between the emission direction of the highest sub-laser beam including the eye safety hazard band and the horizontal plane above the horizontal plane may be set to a larger value according to the level of the safety requirement.

The above angle results are also suitable for a person on another vehicle traveling opposite the vehicle 500, and specific numerical examples and calculation results are omitted here.

In the embodiments of the present disclosure, the beam splitting direction of the sub-laser beam including the human eye safety hazard band may be adjusted by configuring the beam splitting device in the beam splitting unit as shown in fig. 3 and 4, thereby further adjusting the emission direction of the sub-laser beam emitted by the scanning unit. For example, it may be determined which of the light guide devices may be irradiated to the human eye after being emitted by the scanning unit, and appropriate spectroscopic devices and spectroscopic directions are selected accordingly so that the sub-laser beams including the human eye safety hazard band are not received by these light guide devices. In the above embodiment shown in fig. 6, it is possible to determine which of the sub-laser beams guided by the light guide devices have an angle of less than 10 ° with respect to the horizontal plane after being emitted by the scanning unit, and accordingly select appropriate light splitting devices and light splitting directions so that the sub-laser beams including the human eye safety hazard band are not received by these light guide devices.

In addition, in the embodiment of the present disclosure, the beam splitting direction of the sub-laser beam including the human eye safety hazard band may be further adjusted by configuring the light guide device in the beam splitting unit, thereby further adjusting the emission direction of the sub-laser beam emitted by the scanning unit. For example, it may be determined which light guide devices receive sub-laser beams including a human eye safety hazard band, and the light guide devices are configured such that the sub-laser beams guided by them do not strike the human eye after being emitted by the scanning unit. This may be achieved, for example, by changing the beam splitting direction of the laser beam with the collimator 305 of the light guide 302 as described above with reference to fig. 3. In addition, this can be achieved by changing the wavelength distribution of the laser beam in space with the transmission fiber 404 of the light guide 402 as described above with reference to fig. 4.

Thus, in the embodiment of the disclosure, by flexibly adjusting the emergent angles of the sub-laser beams with different wavelengths, the sub-laser beams including the human eye safety hazard band can be prevented from being irradiated to the eyes of the human, and the potential safety hazard is reduced.

Fig. 7 shows a schematic diagram of another operation of a lidar system according to an embodiment of the present disclosure. Fig. 7 differs from fig. 6 in that the laser radar system 100 is at a different elevation from the ground. The lidar system 100 shown in fig. 7 is mounted in front of the vehicle 500, i.e., near the front bumper. In this embodiment, it is assumed that the height H of the lidar system 100 from the ground is between about 0.15 meters and 0.8 meters, depending on the height of the front bumper of the ordinary vehicle. Similar to the above embodiment, it may be assumed in this embodiment that the human eye height of adult P ₁ is between 1.4 meters and 1.9 meters, while the human eye height of child P ₂ is at a minimum of 0.8 meters. In this case, the emission directions of the plurality of sub-laser beams may be configured such that the emission direction of the lowest sub-laser beam including the human eye safety hazard band is below the horizontal plane and the angle with the horizontal plane is 0 ° or more, for example. Similarly, the emission direction of the highest sub-laser beam including the eye safety hazard band may be made above the horizontal plane and at an angle of 15 ° or more from the horizontal plane.

In this embodiment, it will be apparent to those skilled in the art that the minimum value of the angle between the emission direction of the highest sub-laser beam including the eye safety hazard band above the horizontal plane and the horizontal plane may be set to a larger value according to the level of the safety requirement.

Thus, in an embodiment of the present disclosure, depending on the height of the lidar system from the ground, the emission directions of the plurality of sub-laser beams are configured such that the scanning range of the sub-laser beams including the human eye safety hazard band is out of the human eye height range. Thus, the human eye safety hazard can be reduced more reliably, and the safety of the system is increased.

Fig. 8 shows a schematic composition of a vehicle 800 incorporating a lidar system according to an embodiment of the disclosure. Vehicle 800 may include at least a lidar system 802, a vehicle control unit 804, and a motorized system 806. Lidar system 802 may be implemented using lidar system 100 in fig. 1. Accordingly, the light source 812, scanner 814, light receiver 816, and control unit 818 correspond to the supercontinuum laser, scanning unit 104, light receiving unit 106, and control unit 108, respectively, of the lidar system 100. The difference is that the vehicle control unit 804 may be communicatively coupled with the light source 812, the scanner 814, and the light receiver 816 through the control unit 818. In other embodiments, the vehicle control unit 804 may also be communicatively coupled directly to the light source 812, the scanner 814, and the light receiver 816. In some embodiments, lidar system 802 may not include control unit 818. The technique of configuring a lidar system according to embodiments of the present disclosure may be implemented independently by the vehicle control unit 804, or may be implemented in concert in part by the vehicle control unit 804 and in part by the control unit 818. The motorized system 806 may include a power subsystem, a braking subsystem, a steering subsystem, and the like. The vehicle control unit 804 may adjust the maneuver system 806 based on the detection results of the lidar system 802.

In the above embodiments of the present application, the explanation was given taking as an example that the emission directions of the sub laser beams are in the same emission plane and the emission plane is a vertical plane and the scanning direction is a horizontal direction. However, it will be appreciated by those skilled in the art that the direction of the emission plane may be any other direction. In particular, the emission plane may be a plane perpendicular to the vertical plane, i.e. the emission direction of each sub-laser beam is the same as the angle formed by the horizontal plane. This emission plane is similar to the plane through the center of a sphere with the center of the laser radar system. In this case, the scanning direction may be a vertical direction.

It will be appreciated by those skilled in the art that the emission direction of each sub-laser beam may be arbitrarily set in practice, and thus the emission directions of the plurality of sub-laser beams may not lie in the same plane, and may have other settings. In other embodiments of the present disclosure, by adjusting the beam splitting unit, the emission directions of the plurality of sub-laser beams may not be located in the same plane, but within one emission volume, i.e., the space distributed by the sub-laser beams defines one emission volume. Thereby, measurements can be made on the target object within the emission volume. Thus, measurements can be made simultaneously on target objects within the emission volume, further expanding the field of view of the lidar system. In addition, the embodiment of the disclosure can also increase the design flexibility of the laser radar system and adapt to more working scenes.

In addition, in the case where the emission directions of the plurality of sub-laser beams are in the same emission plane and an emission volume is formed, at least two-dimensional scanning can also be provided by providing scanning in one scanning direction.

In the above embodiment, the description has been given taking the example in which the scanning unit 104 scans the sub-laser beams in only one scanning direction. However, those skilled in the art will appreciate that the lidar system may control the scanning unit to scan the sub-laser beam in a plurality of scanning directions when the extent of the spatial divergence of the sub-laser beam is insufficient to achieve the required scan field of view of the lidar system. For example, in one embodiment of the present disclosure, the scanning unit may scan the sub-laser beam in the second direction after completing the scanning in the first scanning direction, thereby moving the sub-laser beam to an area not scanned in the scan field of view of the lidar system. Thereafter, the scanning unit may repeat scanning in the first scanning direction, thereby scanning the area that is not scanned.

In addition, in another embodiment of the present disclosure, the scanning unit may direct the emission beam in a predetermined scanning pattern. Typically, the scanning unit spatially presents a closed scanning pattern when scanned, and periodically repeats the scanning. Common scan patterns include line and column raster, lissajous patterns, spiral patterns, and the like.

In case the scanning unit scans the sub-laser beams in a plurality of scanning directions, for the embodiments shown in fig. 6 and 7, both the emission directions and the scanning directions of the plurality of sub-laser beams may be configured such that the scanning range of the sub-laser beams including the eye safety hazard band is out of the eye height range, thereby still reducing the risk of eye safety.

In the above embodiment, the description has been given taking an example in which the laser radar system 100 includes a non-coaxial optical transceiver system. That is, in this system, there is no overlapping portion of the transmission path from the supercontinuum laser 102 to the target object 120 and the reception path from the target object 120 to the light receiving unit 106, and the laser transmission system and the laser reception system are independent. For example, as shown in fig. 1, the reflected light beam does not reach the light receiving unit 106 via the scanning unit 104 any more. For a non-coaxial optical transceiver system, although the exit angle of the emitted light beam varies with the deflection of the scanner, the total received field of view of the light receiver is fixed and does not vary with the deflection of the scanner.

However, those skilled in the art will appreciate that in some embodiments, lidar system 100 may also include a coaxial optical transceiver system. The coaxial optical transceiver system means that a transmission path from the supercontinuum laser 102 to the target object 120 at least partially overlaps a reception path from the target object 120 to the light receiving unit 106. For example, unlike the one shown in fig. 1, the reflected light beam may reach the light receiving unit 106 via the scanning unit 104 in the reverse direction. For the coaxial optical transceiver system, not only the outgoing angle of the emitted light beam changes with the deflection of the scanner, but also the receiving angle of the light which can be received by the light receiver synchronously changes with the deflection of the scanner, that is, the receiving field of view always keeps equal to the scanning range of the emitted light beam.

For example, a plurality of functions included in one unit in the above embodiments may be implemented by separate devices. Alternatively, the functions realized by the plurality of units in the above embodiments may be realized by separate devices, respectively. In addition, one of the above functions may be implemented by a plurality of units. Such configurations are included within the technical scope of the present disclosure.

The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The term "or" in this disclosure means an inclusive "or" rather than an exclusive "or". References to a "first" component do not necessarily require the provision of a "second" component. Furthermore, unless explicitly indicated otherwise, reference to "a first" or "a second" component does not mean that the referenced component is limited to a particular order. The term "based on" means "based at least in part on.

Claims

1. A lidar system, comprising:

A supercontinuum laser configured to emit a laser beam of a broad spectral range;

A beam splitting unit configured to receive the laser beam from the supercontinuum laser, disperse the laser beam into a plurality of sub-laser beams having different wavelength ranges, and emit each sub-laser beam in a corresponding beam splitting direction;

a scanning unit configured to receive the plurality of sub-laser beams from the beam splitting unit and emit each sub-laser beam in a predetermined emission direction, the scanning unit being configured to be able to change the emission direction of each sub-laser beam so that each sub-laser beam is scanned in at least one scanning direction;

A light receiving unit configured to detect a reflected beam, which is the sub-laser beam reflected by a target object; and

And a control unit configured to control the supercontinuum laser, the scanning unit, and the light receiving unit, and detect the target object from the reflected beam received by the light receiving unit.

2. The lidar system according to claim 1, wherein the light-splitting unit comprises:

A spectroscopic device configured to disperse the laser beam in space according to wavelength; and

A plurality of light guide devices, each of the plurality of light guide devices configured to couple a sub-laser beam having a corresponding wavelength range therein and guide the sub-laser beam to emit the sub-laser beam in a respective spectral direction, respectively.

3. The lidar system according to claim 2, wherein the light-splitting device comprises a light-splitting prism or a light-splitting grating.

4. The lidar system according to claim 2, wherein each of the light-guiding devices comprises:

A microlens positioned in the laser beams dispersed in space by the spectroscopic device and configured to couple sub-laser beams having a wavelength range corresponding to the light guide device into the light guide device;

A transmission fiber coupled to the microlens and guiding the sub-laser beams; and

A collimator coupled to the transmission fiber and configured to collimate the sub-laser beams and emit in the splitting direction.

5. The lidar system of claim 2, wherein the laser radar system comprises a laser beam,

The beam splitting device is configured to split the laser beam in space with a first wavelength distribution;

the plurality of light guide devices are configured to emit the laser beam at a second wavelength distribution,

The first wavelength distribution is different from the second wavelength distribution.

6. The lidar system according to claim 1, wherein the scanning unit comprises a planar mirror, a prism, a polarization grating, a microelectromechanical system (MEMS) galvanometer.

7. The lidar system according to any of claims 1 to 6, wherein the scanning unit is configured such that during scanning of the plurality of sub-laser beams, the emission directions of the plurality of sub-laser beams are in the same emission plane and the emission plane is kept perpendicular to one scanning direction of each sub-laser beam.

8. The lidar system according to claim 7, wherein the emission plane is a plane perpendicular to a vertical plane, and the one scanning direction is a vertical direction.

9. The lidar system according to claim 7, wherein the emission plane is a vertical plane and the one scanning direction is a horizontal direction.

10. The lidar system according to claim 9, wherein the emission directions of the plurality of sub-laser beams are configured such that a scanning range of the sub-laser beams including the eye-safety hazard band is out of the eye-height range, depending on the height of the lidar system from the ground.

11. The lidar system according to claim 10, wherein the height of the lidar system from the ground is in the range of 1.4 meters to 1.7 meters, and an angle between the emission direction of the sub-laser beam including the human eye safety hazard band and the horizontal plane is 10 ° or more.

12. The lidar system according to claim 10, wherein the lidar system has a height from the ground in the range of 0.1 meter-0.4 meter, and

The emission direction of the sub-laser beam including the human eye safety hazard band is below the horizontal plane and has an angle of 0 degree or more with the horizontal plane, and/or

The emission direction of the sub-laser beam including the human eye safety hazard band is above the horizontal plane and has an included angle of 15 degrees or more with the horizontal plane.

13. The lidar system according to claim 10, wherein the eye-safe risk band is a band with a lower eye-safe limit determined in consideration of the power and emission duration of the sub-laser beam.

14. The lidar system according to claim 10, wherein the eye-safe risk band is 400nm to 900nm.

15. A vehicle, comprising:

the lidar system according to any of claims 1 to 14; and

A vehicle control unit is communicatively coupled with the lidar system, the vehicle control unit configured to control operation of the control unit of the lidar system.