Segmenting and grouping light detector array outputs for lidar system

Abstract

A light receiver of a LiDAR system is provided. The light receiver includes a plurality of light detectors configured to receive light from a field-of-view (FOV) of the LiDAR system and generate a plurality of electrical outputs based on the received light. The light receiver further includes a matrix switch device controlled to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors. The matrix switch device is configurable to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system. The light receiver further includes a sampler configured to generate, based on the switched outputs, at least one digital output representing the received light.

Description

SEGMENTING AND GROUPING LIGHT DETECTOR ARRAY OUTPUTS FOR LIDAR SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 527,529, filed July 18, 2023, entitled “SEGMENTING AND GROUPING LIGHT DETECTOR ARRAY OUTPUTS FOR LIDAR SYSTEM,” the content of which is hereby incorporated by reference in its entirety for all purposes.FIELD OF THE TECHNOLOGY

[0002] This disclosure relates generally to a light receiver in a light detection and ranging (LiDAR) system and, more particularly, to segmenting and grouping light detector array outputs for a LiDAR system.BACKGROUND

[0003] Light detection and ranging (LiDAR) systems use light pulses to create an image or point cloud of the external environment. A LiDAR system may be a scanning or non-scanning system. Some typical scanning LiDAR systems include a light source, a light transmitter, a light steering system, and a light detector. The light source generates a light beam that is directed by the light steering system in particular directions when being transmitted from the LiDAR system. When a transmitted light beam is scattered or reflected by an object, a portion of the scattered or reflected light returns to the LiDAR system to form a return light pulse. The light detector detects the return light pulse. Using the difference between the time that the return light pulse is detected and the time that a corresponding light pulse in the light beam is transmitted, the LiDAR system can determine the distance to the object based on the speed of light. This technique of determining the distance is referred to as the time-of-flight (ToF) technique. The light steering system can direct light beams along different paths to allow the LiDAR system to scan the surrounding environment and produce images or point clouds. A typical non-scanning LiDAR system illuminates an entire field-of-view (FOV) rather than scanning through the FOV. An example of the non-scanning LiDAR system is a flash LiDAR, which can also use the ToFtechnique to measure the distance to an object. LiDAR systems can also use techniques other than time-of-flight and scanning to measure the surrounding environment.SUMMARY

[0004] A LiDAR system transmits light pulses to illuminate one or more objects in an FOV and receives return light from the FOV. The return light is formed by scattering or reflecting the transmission light by the one or more objects in the FOV. A LiDAR system often includes a light receiver having one or more light detectors for detecting the return light and generating corresponding electrical output signals (e g., performing light-to-electrical signal conversion). In a LiDAR system, the dynamic range of the light detectors may impose a limit on the light receiver of the LiDAR system. A typical number of the dynamic range is approximately 40-50 dB, while the dynamic range of an optical echo is usually great than 120 dB. Therefore, an optical echo may saturate the light detector of a LiDAR system. At least partially because of the limited dynamic range of the light detectors, a LiDAR system may not be optimized for both long-range detection and short-range detection (or optimized for both weak signal detection and large signal detection).

[0005] This disclosure provides techniques for improving the light receiver of a LiDAR system to provide the flexibility for both long-range and short-range detections, and to reduce the crosstalk between multiple signal processing channels in a LiDAR system. In one embodiment, a light receiver of a LiDAR system is provided. The light receiver includes a plurality of light detectors configured to receive light from a field-of-view (FOV) of the LiDAR system and generate a plurality of electrical outputs based on the received light. The light receiver further includes a matrix switch device controlled to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors. The matrix switch device is configurable to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system. The light receiver further includes a sampler configured to generate, based on the switched outputs, at least one digital output representing the received light.

[0006] In another embodiment, a LiDAR system is provided. The system includes a light source configured to transmit laser light; a scanner configured to scan the laser light to a field-of-view; acontroller; and a light receiver. The light receiver includes a plurality of light detectors configured to receive light from a field-of-view (FOV) of the LiDAR system and generate a plurality of electrical outputs based on the received light. The light receiver further includes a matrix switch device controlled to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors. The matrix switch device is configurable to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system. The light receiver further includes a sampler configured to generate, based on the switched outputs, at least one digital output representing the received light.

[0007] In another embodiment, a method for performing light detection by a light receiver is provided. The method comprises: receiving, by a plurality of light detectors, light from a field- of-view (FOV) of a LiDAR system; generating a plurality of electrical outputs based on the received light; and controlling, by control circuitry, a matrix switch device to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors. Controlling the matrix switch device comprises: configuring the matrix switch device to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system. The method further comprises generating, by a sampler and based on the switched outputs, at least one digital output representing the received light.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present application can be best understood by reference to the embodiments described below taken in conjunction with the accompanying drawing figures, in which like parts may be referred to by like numerals.

[0009] FIG. 1 illustrates one or more example LiDAR systems disposed or included in a motor vehicle.

[0010] FIG. 2 is a block diagram illustrating interactions between an example LiDAR system and multiple other systems including a vehicle perception and planning system.

[0011] FIG. 3 is a block diagram illustrating an example LiDAR system.

[0012] FIG. 4A is a block diagram illustrating an example fiber-based laser source.

[0013] FIG. 4B is a block diagram illustrating an example semiconductor-based laser source.

[0014] FIGs. 5A-5C illustrate an example LiDAR system using pulse signals to measure distances to objects disposed in a field-of-view (FOV).

[0015] FIG. 6 is a block diagram illustrating an example apparatus used to implement systems, apparatus, and methods in various embodiments.

[0016] FIG. 7 is a block diagram illustrating an example light receiver having a matrix switch device, in accordance with various embodiments.

[0017] FIGs. 8A-8B are block diagrams illustrating example light detectors arranged in arrays, in accordance with various embodiments.

[0018] FIGs. 9A-9H illustrate example light detectors and a matrix switch device configured to have various switching settings, in accordance with various embodiments.

[0019] FIG. 10 illustrates a LiDAR system configured to perform both long-range detection and short-range detection, in accordance with various embodiments.

[0020] FIGs. 11A-1 IB are block diagrams illustrating example samplers in accordance with various embodiments.

[0021] FIG. 12A-12B are flowcharts illustrating a method for performing light detection in accordance with various embodiments.DETAILED DESCRIPTION

[0022] To provide a more thorough understanding of various embodiments of the present invention, the following description sets forth numerous specific details, such as specific configurations, parameters, examples, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention but is intended to provide a better description of the exemplary embodiments.

[0023] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise:

[0024] The phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment, though it may. Thus, as described below, various embodiments of the disclosure may be readily combined, without departing from the scope or spirit of the invention.

[0025] As used herein, the term “or” is an inclusive “or” operator and is equivalent to the term “and / or,” unless the context clearly dictates otherwise.

[0026] The term “based on” is not exclusive and allows for being based on additional factors not described unless the context clearly dictates otherwise.

[0027] As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously. Within the context of a networked environment where two or more components or devices are able to exchange data, the terms “coupled to” and “coupled with” are also used to mean “communicatively coupled with”, possibly via one or more intermediary devices. The components or devices can be optical, mechanical, and / or electrical devices.

[0028] Although the following description uses terms “first,” “second,” etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first switch setting could be termed a second switch setting and, similarly, a second switch setting could be termed a first switch setting without departing from the scope of the various described examples. The first switch setting and the second switch setting can both be switch settings and, in some cases, can be separate and different switch settings.

[0029] In addition, throughout the specification, the meaning of “a”, “an”, and “the” includes plural references, and the meaning of “in” includes “in” and “on”.

[0030] Although some of the various embodiments presented herein constitute a single combination of inventive elements, it should be appreciated that the inventive subject matter is considered to include all possible combinations of the disclosed elements. As such, if one embodiment comprises elements A, B, and C, and another embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remainingcombinations of A, B, C, or D, even if not explicitly discussed herein. Further, the transitional term “comprising” means to have as parts or members, or to be those parts or members. As used herein, the transitional term “comprising” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

[0031] As used in the description herein and throughout the claims that follow, when a system, engine, server, device, module, or other computing element is described as being configured to perform or execute functions on data in a memory, the meaning of “configured to” or “programmed to” is defined as one or more processors or cores of the computing element being programmed by a set of software instructions stored in the memory of the computing element to execute the set of functions on target data or data objects stored in the memory.

[0032] It should be noted that any language directed to a computer should be read to include any suitable combination of computing devices or network platforms, including servers, interfaces, systems, databases, agents, peers, engines, controllers, modules, or other types of computing devices operating individually or collectively. One should appreciate the computing devices comprise a processor configured to execute software instructions stored on a tangible, non- transitory computer readable storage medium (e.g., hard drive, FPGA, PLA, solid state drive, RAM, flash, ROM, or any other volatile or non-volatile storage devices). The software instructions configure or program the computing device to provide the roles, responsibilities, or other functionality as discussed below with respect to the disclosed apparatus. Further, the disclosed technologies can be embodied as a computer program product that includes a non- transitory computer readable medium storing the software instructions that causes a processor to execute the disclosed steps associated with implementations of computer-based algorithms, processes, methods, or other instructions. In some embodiments, the various servers, systems, databases, or interfaces exchange data using standardized protocols or algorithms, possibly based on HTTP, HTTPS, AES, public-private key exchanges, web service APIs, known financial transaction protocols, or other electronic information exchanging methods. Data exchanges among devices can be conducted over a packet-switched network, the Internet, LAN, WAN, VPN, or other type of packet switched network; a circuit switched network; cell switched network; or other type of network.

[0033] A LiDAR system transmits light pulses to illuminate one or more objects in an FOV and receives return light from the FOV. The return light is formed by scattering or reflecting the transmission light by the one or more objects. A LiDAR system often includes a light receiver having one or more light detectors for detecting the return light and generating corresponding electrical output signals (e.g., performing light-to-electrical signal conversion). In a LiDAR system, the dynamic range of the light detectors may impose a limit on the light receiver of the LiDAR system. A typical number of the dynamic range is approximately 40-50 dB, while the dynamic range of an optical echo is usually greater than 120 dB.

[0034] At least partially because of the limited dynamic range of the light detectors, a LiDAR system may not be optimized for both long-range detection and short-range detection (or optimized for both weak signal detection and large signal detection). For example, if a LiDAR is optimized for long-range detection (in which the signal strength of the return light may be weak), the light detectors may be configured to be very sensitive so that they can detect weak return light. If such a long-range LiDAR system is used to detect a strong return light generated by a nearby object, the strong return light may saturate the light detectors, causing it to exceed the upper limit of the dynamic range). On the other hand, if a LiDAR is optimized for short-range detection (in which the signal strength of the return light may usually be strong), the light detectors may be configured to be less sensitive to reduce the chance of being saturated. But such a short-range detection LiDAR system may not be able to detect weak return light generated by a far-away object, resulting in missing detections for long-range objects. Therefore, for a LiDAR system, it may be difficult to achieve good performance for both long-range and short-range detections.

[0035] In addition, a LiDAR system nowadays may include multiple-channel transceivers that operate simultaneously. Multiple-channel transceivers can transmit multiple light beams for scanning the FOV, and receive return light corresponding to the multiple transmitted light beams. The return light can be detected in parallel and converted to electrical signals for downstream processing to generate a point cloud. Multiple-channel transceivers and associated signal processing increase the resolution of the point cloud, improve the LiDAR processing efficiency and throughput, and enhance the overall performance of the LiDAR system. On the other hand, if multiple-channel transceivers in a LiDAR system operate simultaneously, crosstalk between the channels may increase, thereby reducing the signal-to-noise ratio (SNR) for aparticular channel. The reduced SNR. may cause performance degradation of the LiDAR system, resulting in a point cloud that has a higher noise level. If a LiDAR system is used in a moveable platform like a vehicle, this may cause a misdetection. Therefore, there is continual need for improving the light receiver of a LiDAR system to provide the flexibility for both performing both long-range and short-range detections, and to reduce the crosstalk between multiple transceiver channels and / or signal processing channels in a LiDAR system.

[0036] Embodiments of present invention are described below. In various embodiments of the present invention, a light receiver of a LiDAR system is provided. The light receiver includes a plurality of light detectors configured to receive light from a field-of-view (FOV) of the LiDAR system and generate a plurality of electrical outputs based on the received light. The light receiver further includes a matrix switch device controlled to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors. The matrix switch device is configurable to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system. The light receiver further includes a sampler configured to generate, based on the switched outputs, at least one digital output representing the received light. The embodiments described herein provide techniques for improving the light receiver of a LiDAR system to provide the flexibility for both long-range and short-range detections, and to reduce the crosstalk between multiple signal processing channels in a LiDAR system.

[0037] FIG. 1 illustrates one or more example LiDAR systems 110 and 120A-120I disposed or included in a motor vehicle 100. Vehicle 100 can be a car, a sport utility vehicle (SUV), a truck, a train, a wagon, a bicycle, a motorcycle, a tricycle, a bus, a mobility scooter, a tram, a ship, a boat, an underwater vehicle, an airplane, a helicopter, an unmanned aviation vehicle (UAV), a spacecraft, etc. Motor vehicle 100 can be a vehicle having any automated level. For example, motor vehicle 100 can be a partially automated vehicle, a highly automated vehicle, a fully automated vehicle, or a driverless vehicle. A partially automated vehicle can perform some driving functions without a human driver’s intervention. For example, a partially automated vehicle can perform blind-spot monitoring, lane keeping and / or lane changing operations, automated emergency braking, smart cruising and / or traffic following, or the like. Certain operations of a partially automated vehicle may be limited to specific applications or driving scenarios (e.g., limited to only freeway driving). A highly automated vehicle can generallyperform all operations of a partially automated vehicle but with less limitations. A highly automated vehicle can also detect its own limits in operating the vehicle and ask the driver to take over the control of the vehicle when necessary. A fully automated vehicle can perform all vehicle operations without a driver’s intervention but can also detect its own limits and ask the driver to take over when necessary. A driverless vehicle can operate on its own without any driver intervention.

[0038] In typical configurations, motor vehicle 100 comprises one or more LiDAR systems 110 and 120A-120I. Each of LiDAR systems 110 and 120A-120I can be a scanning-based LiDAR system and / or a non-scanning LiDAR system (e.g., a flash LiDAR). A scanning-based LiDAR system scans one or more light beams in one or more directions (e.g., horizontal and vertical directions) to detect objects in a field-of-view (FOV). A non-scanning based LiDAR system transmits laser light to illuminate an FOV without scanning. For example, a flash LiDAR is a type of non-scanning based LiDAR system. A flash LiDAR can transmit laser light to simultaneously illuminate an FOV using a single light pulse or light shot.

[0039] A LiDAR system is a frequently-used sensor of a vehicle that is at least partially automated. In one embodiment, as shown in FIG. 1, motor vehicle 100 may include a single LiDAR system 110 (e.g., without LiDAR systems 120A-120I) disposed at the highest position of the vehicle (e.g., at the vehicle roof). Disposing LiDAR system 110 at the vehicle roof facilitates a 360-degree scanning around vehicle 100. In some other embodiments, motor vehicle 100 can include multiple LiDAR systems, including two or more of systems 110 and / or 120A-120I. As shown in FIG. 1, in one embodiment, multiple LiDAR systems 110 and / or 120A-120I are attached to vehicle 100 at different locations of the vehicle. For example, LiDAR system 120A is attached to vehicle 100 at the front right corner; LiDAR system 120B is attached to vehicle 100 at the front center position; LiDAR system 120C is attached to vehicle 100 at the front left corner; LiDAR system 120D is attached to vehicle 100 at the right-side rear view mirror; LiDAR system 120E is attached to vehicle 100 at the left-side rear view mirror; LiDAR system 120F is attached to vehicle 100 at the back center position; LiDAR system 120G is attached to vehicle 100 at the back right corner; LiDAR system 120H is attached to vehicle 100 at the back left corner; and / or LiDAR system 1201 is attached to vehicle 100 at the center towards the backend (e.g., back end of the vehicle roof). It is understood that one or more LiDAR systems can be distributed and attached to a vehicle in any desired manner and FIG. 1 only illustrates oneembodiment. As another example, LiDAR systems 120D and 120E may be attached to the B- pillars of vehicle 100 instead of the rear-view mirrors. As another example, LiDAR system 120B may be attached to the windshield of vehicle 100 instead of the front bumper.

[0040] In some embodiments, LiDAR systems 110 and 120A-120I are independent LiDAR systems having their own respective laser sources, control electronics, transmitters, receivers, and / or steering mechanisms. In other embodiments, some of LiDAR systems 110 and 120A- 1201 can share one or more components, thereby forming a distributed sensor system. In one example, optical fibers are used to deliver laser light from a centralized laser source to all LiDAR systems. For instance, system 110 (or another system that is centrally positioned or positioned anywhere inside the vehicle 100) includes a light source, a transmitter, and a light detector, but has no steering mechanisms. System 110 may distribute transmission light to each of systems 120A-120I. The transmission light may be distributed via optical fibers. Optical connectors can be used to couple the optical fibers to each of system 110 and 120A-120I. In some examples, one or more of systems 120A-120I include steering mechanisms but no light sources, transmitters, or light detectors. A steering mechanism may include one or more moveable mirrors such as one or more polygon mirrors, one or more single plane mirrors, one or more multi-plane mirrors, or the like. Embodiments of the light source, transmitter, steering mechanism, and light detector are described in more detail below. Via the steering mechanisms, one or more of systems 120A-120I scan light into one or more respective FOVs and receive corresponding return light. The return light is formed by scattering or reflecting the transmission light by one or more objects in the FOVs. Systems 120A-120I may also include collection lens and / or other optics to focus and / or direct the return light into optical fibers, which deliver the received return light to system 110. System 110 includes one or more light detectors for detecting the received return light. In some examples, system 110 is disposed inside a vehicle such that it is in a temperature-controlled environment, while one or more systems 120A-120I may be at least partially exposed to the external environment.

[0041] FIG. 2 is a block diagram 200 illustrating interactions between vehicle onboard LiDAR system(s) 210 and multiple other systems including a vehicle perception and planning system 220. LiDAR system(s) 210 can be mounted on or integrated to a vehicle. LiDAR system(s) 210 include sensor(s) that scan laser light to the surrounding environment to measure the distance, angle, and / or velocity of objects. Based on the scattered light that returned to LiDAR system(s)210, it can generate sensor data (e.g., image data or 3D point cloud data) representing the perceived external environment.

[0042] LiDAR system(s) 210 can include one or more of short-range LiDAR sensors, mediumrange LiDAR sensors, and long-range LiDAR sensors. A short-range LiDAR sensor measures objects located up to about 20-50 meters from the LiDAR sensor. Short-range LiDAR sensors can be used for, e.g., monitoring nearby moving objects (e.g., pedestrians crossing street in a school zone), parking assistance applications, or the like. A medium-range LiDAR sensor measures objects located up to about 70-200 meters from the LiDAR sensor. Medium-range LiDAR sensors can be used for, e.g., monitoring road intersections, assistance for merging onto or leaving a freeway, or the like. A long-range LiDAR sensor measures objects located up to about 200 meters and beyond. Long-range LiDAR sensors are typically used when a vehicle is travelling at a high speed (e.g., on a freeway), such that the vehicle’s control systems may only have a few seconds (e.g., 6-8 seconds) to respond to any situations detected by the LiDAR sensor. As shown in FIG. 2, in one embodiment, the LiDAR sensor data can be provided to vehicle perception and planning system 220 via a communication path 213 for further processing and controlling the vehicle operations. Communication path 213 can be any wired or wireless communication links that can transfer data.

[0043] With reference still to FIG. 2, in some embodiments, other vehicle onboard sensor(s) 230 are configured to provide additional sensor data separately or together with LiDAR system(s) 210. Other vehicle onboard sensors 230 may include, for example, one or more camera(s) 232, one or more radar(s) 234, one or more ultrasonic sensor(s) 236, and / or other sensor(s) 238. Camera(s) 232 can take images and / or videos of the external environment of a vehicle. Camera(s) 232 can take, for example, high-definition (HD) videos having millions of pixels in each frame. A camera includes image sensors that facilitate producing monochrome or color images and videos. Color information may be important in interpreting data for some situations (e.g., interpreting images of traffic lights). Color information may not be available from other sensors such as LiDAR or radar sensors. Camera(s) 232 can include one or more of narrowfocus cameras, wider-focus cameras, side-facing cameras, infrared cameras, fisheye cameras, or the like. The image and / or video data generated by camera(s) 232 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations. Communication path 233 can be any wired or wirelesscommunication links that can transfer data. Camera(s) 232 can be mounted on, or integrated to, a vehicle at any location (e.g., rear-view mirrors, pillars, front grille, and / or back bumpers, etc.).

[0044] Other vehicle onboard sensor(s) 230 can also include radar sensor(s) 234. Radar sensor(s) 234 use radio waves to determine the range, angle, and velocity of objects. Radar sensor(s) 234 produce electromagnetic waves in the radio or microwave spectrum. The electromagnetic waves reflect off an object and some of the reflected waves return to the radar sensor, thereby providing information about the object’s position and velocity. Radar sensor(s) 234 can include one or more of short-range radar(s), medium-range radar(s), and long-range radar(s). A short-range radar measures objects located at about 0.1-30 meters from the radar. A short-range radar is useful in detecting objects located near the vehicle, such as other vehicles, buildings, walls, pedestrians, bicyclists, etc. A short-range radar can be used to detect a blind spot, assist in lane changing, provide rear-end collision warning, assist in parking, provide emergency braking, or the like. A medium-range radar measures objects located at about 30-80 meters from the radar. A long-range radar measures objects located at about 80-200 meters. Medium- and / or long-range radars can be useful in, for example, traffic following, adaptive cruise control, and / or highway automatic braking. Sensor data generated by radar sensor(s) 234 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations. Radar sensor(s) 234 can be mounted on, or integrated to, a vehicle at any location (e.g., rear-view mirrors, pillars, front grille, and / or back bumpers, etc.).

[0045] Other vehicle onboard sensor(s) 230 can also include ultrasonic sensor(s) 236. Ultrasonic sensor(s) 236 use acoustic waves or pulses to measure objects located external to a vehicle. The acoustic waves generated by ultrasonic sensor(s) 236 are transmitted to the surrounding environment. At least some of the transmitted waves are reflected off an object and return to the ultrasonic sensor(s) 236. Based on the return signals, a distance of the object can be calculated. Ultrasonic sensor(s) 236 can be useful in, for example, checking blind spots, identifying parking spaces, providing lane changing assistance into traffic, or the like. Sensor data generated by ultrasonic sensor(s) 236 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations. Ultrasonic sensor(s) 236 can be mounted on, or integrated to, a vehicle at any location (e.g., rearview mirrors, pillars, front grille, and / or back bumpers, etc.).

[0046] In some embodiments, one or more other sensor(s) 238 may be attached in a vehicle and may also generate sensor data. Other sensor(s) 238 may include, for example, global positioning systems (GPS), inertial measurement units (IMU), or the like. Sensor data generated by other sensor(s) 238 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations. It is understood that communication path 233 may include one or more communication links to transfer data between the various sensor(s) 230 and vehicle perception and planning system 220.

[0047] In some embodiments, as shown in FIG. 2, sensor data from other vehicle onboard sensor(s) 230 can be provided to vehicle onboard LiDAR system(s) 210 via communication path 231 . LiDAR system(s) 210 may process the sensor data from other vehicle onboard sensor(s) 230. For example, sensor data from camera(s) 232, radar sensor(s) 234, ultrasonic sensor(s) 236, and / or other sensor(s) 238 may be correlated or fused with sensor data LiDAR system(s) 210, thereby at least partially offloading the sensor fusion process performed by vehicle perception and planning system 220. It is understood that other configurations may also be implemented for transmitting and processing sensor data from the various sensors (e.g., data can be transmitted to a cloud or edge computing service provider for processing and then the processing results can be transmitted back to the vehicle perception and planning system 220 and / or LiDAR system 210).

[0048] With reference still to FIG. 2, in some embodiments, sensors onboard other vehicle(s) 250 are used to provide additional sensor data separately or together with LiDAR system(s) 210. For example, two or more nearby vehicles may have their own respective LiDAR sensor(s), camera(s), radar sensor(s), ultrasonic sensor(s), etc. Nearby vehicles can communicate and share sensor data with one another. Communications between vehicles are also referred to as V2V (vehicle to vehicle) communications. For example, as shown in FIG. 2, sensor data generated by other vehicle(s) 250 can be communicated to vehicle perception and planning system 220 and / or vehicle onboard LiDAR system(s) 210, via communication path 253 and / or communication path 251, respectively. Communication paths 253 and 251 can be any wired or wireless communication links that can transfer data.

[0049] Sharing sensor data facilitates a better perception of the environment external to the vehicles. For instance, a first vehicle may not sense a pedestrian that is behind a second vehicle but is approaching the first vehicle. The second vehicle may share the sensor data related to thispedestrian with the first vehicle such that the first vehicle can have additional reaction time to avoid collision with the pedestrian. In some embodiments, similar to data generated by sensor(s) 230, data generated by sensors onboard other vehicle(s) 250 may be correlated or fused with sensor data generated by LiDAR system(s) 210 (or with other LiDAR systems located in other vehicles), thereby at least partially offloading the sensor fusion process performed by vehicle perception and planning system 220.

[0050] In some embodiments, intelligent infrastructure system(s) 240 are used to provide sensor data separately or together with LiDAR system(s) 210. Certain infrastructures may be configured to communicate with a vehicle to convey information and vice versa.Communications between a vehicle and infrastructures are generally referred to as V2I (vehicle to infrastructure) communications. For example, intelligent infrastructure system(s) 240 may include an intelligent traffic light that can convey its status to an approaching vehicle in a message such as “changing to yellow in 5 seconds.” Intelligent infrastructure system(s) 240 may also include its own LiDAR system mounted near an intersection such that it can convey traffic monitoring information to a vehicle. For example, a left-turning vehicle at an intersection may not have sufficient sensing capabilities because some of its own sensors may be blocked by traffic in the opposite direction. In such a situation, sensors of intelligent infrastructure system(s) 240 can provide useful data to the left-turning vehicle. Such data may include, for example, traffic conditions, information of objects in the direction the vehicle is turning to, traffic light status and predictions, or the like. These sensor data generated by intelligent infrastructure system(s) 240 can be provided to vehicle perception and planning system 220 and / or vehicle onboard LiDAR system(s) 210, via communication paths 243 and / or 241, respectively.Communication paths 243 and / or 241 can include any wired or wireless communication links that can transfer data. For example, sensor data from intelligent infrastructure system(s) 240 may be transmitted to LiDAR system(s) 210 and correlated or fused with sensor data generated by LiDAR system(s) 210, thereby at least partially offloading the sensor fusion process performed by vehicle perception and planning system 220. V2V and V2I communications described above are examples of vehicle-to-X (V2X) communications, where the “X” represents any other devices, systems, sensors, infrastructure, or the like that can share data with a vehicle.

[0051] With reference still to FIG. 2, via various communication paths, vehicle perception and planning system 220 receives sensor data from one or more of LiDAR system(s) 210, othervehicle onboard sensor(s) 230, other vehicle(s) 250, and / or intelligent infrastructure system(s) 240. In some embodiments, different types of sensor data are correlated and / or integrated by a sensor fusion sub-system 222. For example, sensor fusion sub-system 222 can generate a 360- degree model using multiple images or videos captured by multiple cameras disposed at different positions of the vehicle. Sensor fusion sub-system 222 obtains sensor data from different types of sensors and uses the combined data to perceive the environment more accurately. For example, a vehicle onboard camera 232 may not capture a clear image because it is facing the Sun or a light source (e.g., another vehicle’s headlight during nighttime) directly. A LiDAR system 210 may not be affected as much and therefore sensor fusion sub-system 222 can combine sensor data provided by both camera 232 and LiDAR system 210, and use the sensor data provided by LiDAR system 210 to compensate the unclear image captured by camera 232. As another example, in a rainy or foggy weather, a radar sensor 234 may work better than a camera 232 or a LiDAR system 210. Accordingly, sensor fusion sub-system 222 may use sensor data provided by the radar sensor 234 to compensate the sensor data provided by camera 232 or LiDAR system 210.

[0052] In other examples, sensor data generated by other vehicle onboard sensor(s) 230 may have a lower resolution (e.g., radar sensor data) and thus may need to be correlated and confirmed by LiDAR system(s) 210, which usually has a higher resolution. For example, a sewage cover (also referred to as a manhole cover) may be detected by radar sensor 234 as an object towards which a vehicle is approaching. Due to the low-resolution nature of radar sensor 234, vehicle perception and planning system 220 may not be able to determine whether the object is an obstacle that the vehicle needs to avoid. High-resolution sensor data generated by LiDAR system(s) 210 thus can be used to correlated and confirm that the object is a sewage cover and causes no harm to the vehicle.

[0053] Vehicle perception and planning system 220 further comprises an object classifier 223. Using raw sensor data and / or correlated / fused data provided by sensor fusion sub-system 222, object classifier 223 can use any computer vision techniques to detect and classify the objects and estimate the positions of the objects. In some embodiments, object classifier 223 can use machine-learning based techniques to detect and classify objects. Examples of the machinelearning based techniques include utilizing algorithms such as region-based convolutional neural networks (R-CNN), Fast R-CNN, Faster R-CNN, histogram of oriented gradients (HOG),region-based fully convolutional network (R-FCN), single shot detector (SSD), spatial pyramid pooling (SPP-net), and / or You Only Look Once (Yolo).

[0054] Vehicle perception and planning system 220 further comprises a road detection subsystem 224. Road detection sub-system 224 localizes the road and identifies objects and / or markings on the road. For example, based on raw or fused sensor data provided by radar sensor(s) 234, camera(s) 232, and / or LiD AR system(s) 210, road detection sub-system 224 can build a 3D model of the road based on machine-learning techniques (e.g., pattern recognition algorithms for identifying lanes). Using the 3D model of the road, road detection sub-system 224 can identify objects (e.g., obstacles or debris on the road) and / or markings on the road (e.g., lane lines, turning marks, crosswalk marks, or the like).

[0055] Vehicle perception and planning system 220 further comprises a localization and vehicle posture sub-system 225. Based on raw or fused sensor data, localization and vehicle posture sub-system 225 can determine position of the vehicle and the vehicle’s posture. For example, using sensor data from LiD AR system(s) 210, camera(s) 232, and / or GPS data, localization and vehicle posture sub-system 225 can determine an accurate position of the vehicle on the road and the vehicle’s six degrees of freedom (e.g., whether the vehicle is moving forward or backward, up or down, and left or right). In some embodiments, high-definition (HD) maps are used for vehicle localization. HD maps can provide highly detailed, three-dimensional, computerized maps that pinpoint a vehicle’s location. For instance, using the HD maps, localization and vehicle posture sub-system 225 can determine precisely the vehicle’s current position (e.g., which lane of the road the vehicle is currently in, how close it is to a curb or a sidewalk) and predict vehicle’s future positions.

[0056] Vehicle perception and planning system 220 further comprises obstacle predictor 226. Objects identified by object classifier 223 can be stationary (e.g., a light pole, a road sign) or dynamic (e.g., a moving pedestrian, bicycle, another car). For moving objects, predicting their moving path or future positions can be important to avoid collision. Obstacle predictor 226 can predict an obstacle trajectory and / or warn the driver or the vehicle planning sub-system 228 about a potential collision. For example, if there is a high likelihood that the obstacle’s trajectory intersects with the vehicle’s current moving path, obstacle predictor 226 can generate such a warning. Obstacle predictor 226 can use a variety of techniques for making such aprediction. Such techniques include, for example, constant velocity or acceleration models, constant turn rate and velocity / acceleration models, Kalman Filter and Extended Kalman Filter based models, recurrent neural network (RNN) based models, long short-term memory (LSTM) neural network based models, encoder-decoder RNN models, or the like.

[0057] With reference still to FIG. 2, in some embodiments, vehicle perception and planning system 220 further comprises vehicle planning sub-system 228. Vehicle planning sub-system 228 can include one or more planners such as a route planner, a driving behaviors planner, and a motion planner. The route planner can plan the route of a vehicle based on the vehicle’s current location data, target location data, traffic information, etc. The driving behavior planner adjusts the timing and planned movement based on how other objects might move, using the obstacle prediction results provided by obstacle predictor 226. The motion planner determines the specific operations the vehicle needs to follow. The planning results are then communicated to vehicle control system 280 via vehicle interface 270. The communication can be performed through communication paths 227 and 271, which include any wired or wireless communication links that can transfer data.

[0058] Vehicle control system 280 controls the vehicle’s steering mechanism, throttle, brake, etc., to operate the vehicle according to the planned route and movement. In some examples, vehicle perception and planning system 220 may further comprise a user interface 260, which provides a user (e g., a driver) access to vehicle control system 280 to, for example, override or take over control of the vehicle when necessary. User interface 260 may also be separate from vehicle perception and planning system 220. User interface 260 can communicate with vehicle perception and planning system 220, for example, to obtain and display raw or fused sensor data, identified objects, vehicle’s location / posture, etc. These displayed data can help a user to better operate the vehicle. User interface 260 can communicate with vehicle perception and planning system 220 and / or vehicle control system 280 via communication paths 221 and 261 respectively, which include any wired or wireless communication links that can transfer data. It is understood that the various systems, sensors, communication links, and interfaces in FIG. 2 can be configured in any desired manner and not limited to the configuration shown in FIG. 2.

[0059] FIG. 3 is a block diagram illustrating an example LiDAR system 300. LiDAR system 300 can be used to implement LiDAR systems 110, 120A-120I, and / or 210 shown in FIGs. 1 and2. In one embodiment, LiDAR system 300 comprises a light source 310, a transmitter 320, an optical receiver and light detector 330, a steering system 340, and control circuitry 350. These components are coupled together using communications paths 312, 314, 322, 332, 342, 352, 362, and 372. These communications paths include communication links (wired or wireless, bidirectional or unidirectional) among the various LiDAR system components, but need not be physical components themselves. While the communications paths can be implemented by one or more electrical wires, buses, or optical fibers, the communication paths can also be wireless channels or free-space optical paths so that no physical communication medium is present. For example, in one embodiment of LiDAR system 300, communication path 314 between light source 310 and transmitter 320 may be implemented using one or more optical fibers. Communication paths 332 and 352 may represent optical paths implemented using free space optical components and / or optical fibers. And communication paths 312, 322, 342, and 362 may be implemented using one or more electrical wires that carry electrical signals. The communications paths can also include one or more of the above types of communication mediums (e.g., they can include an optical fiber and a free-space optical component, or include one or more optical fibers and one or more electrical wires).

[0060] In some embodiments, LiDAR system 300 can be a coherent LiDAR system. One example is a frequency-modulated continuous-wave (FMCW) LiDAR. Coherent LiDARs detect objects by mixing return light from the objects with light from the coherent laser transmitter. Thus, as shown in FIG. 3, if LiDAR system 300 is a coherent LiDAR, it may include a route 372 providing a portion of transmission light from transmitter 320 to optical receiver and light detector 330. Route 372 may include one or more optics (e.g., optical fibers, lens, mirrors, etc.) for providing the light from transmitter 320 to optical receiver and light detector 330. The transmission light provided by transmitter 320 may be modulated light and can be split into two portions. One portion is transmitted to the FOV, while the second portion is sent to the optical receiver and light detector 330 of the LiDAR system 300. The second portion is also referred to as the light that is kept local (LO) to the LiDAR system 300. The transmission light is scattered or reflected by various objects in the FOV and at least a portion of it forms return light. The return light is subsequently detected and interferometrically recombined with the second portion of the transmission light that was kept local. Coherent LiDAR provides a means of optically sensing an object’s range as well as its relative velocity along the line-of-sight (LOS).

[0061] LiDAR system 300 can also include other components not depicted in FIG. 3, such as power buses, power supplies, LED indicators, switches, etc. Additionally, other communication connections among components may be present, such as a direct connection between light source 310 and optical receiver and light detector 330 to provide a reference signal so that the time from when a light pulse is transmitted until a return light pulse is detected can be accurately measured.

[0062] Light source 310 outputs laser light for illuminating objects in a field of view (FOV). The laser light can be infrared light having a wavelength in the range of 700 nm to 1mm. Light source 310 can be, for example, a semiconductor-based laser (e.g., a diode laser) and / or a fiberbased laser. A semiconductor-based laser can be, for example, an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), an external-cavity diode laser, a vertical- extemal-cavity surface-emitting laser, a distributed feedback (DFB) laser, a distributed Bragg reflector (DBR) laser, an interband cascade laser, a quantum cascade laser, a quantum well laser, a double heterostructure laser, or the like. A fiber-based laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium, and / or holmium. In some embodiments, a fiber laser is based on double-clad fibers, in which the gain medium forms the core of the fiber surrounded by two layers of cladding. The double-clad fiber allows the core to be pumped with a high-power beam, thereby enabling the laser source to be a high power fiber laser source.

[0063] In some embodiments, light source 310 comprises a master oscillator (also referred to as a seed laser) and power amplifier (MOP A). The power amplifier amplifies the output power of the seed laser. The power amplifier can be a fiber amplifier, a bulk amplifier, or a semiconductor optical amplifier. The seed laser can be a diode laser (e.g., a Fabry-Perot cavity laser, a distributed feedback laser), a solid-state bulk laser, or a tunable external-cavity diode laser. In some embodiments, light source 310 can be an optically pumped microchip laser. Microchip lasers are alignment-free monolithic solid-state lasers where the laser crystal is directly contacted with the end mirrors of the laser resonator. A microchip laser is typically pumped with a laser diode (directly or using a fiber) to obtain the desired output power. A microchip laser can be based on neodymium-doped yttrium aluminum garnet (Y3AI5O12) laser crystals (i.e., Nd:YAG), or neodymium-doped vanadate (i.e., NDiYVCh) laser crystals. In some examples, light source 310 may have multiple amplification stages to achieve a high power gain such that the laser output can have high power, thereby enabling the LiDAR system to have a longscanning range. In some examples, the power amplifier of light source 310 can be controlled such that the power gain can be varied to achieve any desired laser output power.

[0064] FIG. 4A is a block diagram illustrating an example fiber-based laser source 400 having a seed laser and one or more pumps (e.g., laser diodes) for pumping desired output power. Fiberbased laser source 400 is an example of light source 310 depicted in FIG. 3. In some embodiments, fiber-based laser source 400 comprises a seed laser 402 configured to generate initial light pulses of one or more wavelengths (e.g., infrared wavelengths such as 1550 nm), which are provided to a wavelength-division multiplexor (WDM) 404 via an optical fiber 403. Fiber-based laser source 400 further comprises a pump 406 for providing laser power (e.g., of a different wavelength, such as 980 nm) to WDM 404 via an optical fiber 405. WDM 404 multiplexes the light pulses provided by seed laser 402 and the laser power provided by pump 406 onto a single optical fiber 407. The output of WDM 404 can then be provided to one or more pre-amplifier(s) 408 via optical fiber 407. Pre-amplifier(s) 408 can be optical amplifier(s) that amplify optical signals (e.g., with about 10-30 dB gain). In some embodiments, preamplifiers) 408 are low noise amplifiers. Pre-amplifier(s) 408 output to an optical combiner 410 via an optical fiber 409. Combiner 410 combines the output laser light of pre-amplifier(s) 408 with the laser power provided by pump 412 via an optical fiber 411. Combiner 410 can combine optical signals having the same wavelength or different wavelengths. One example of a combiner is a WDM. Combiner 410 provides combined optical signals to a booster amplifier 414, which produces output light pulses via optical fiber 415. The booster amplifier 414 provides further amplification of the optical signals (e.g., another 20-40 dB). The output light pulses can then be transmitted to transmitter 320 and / or steering mechanism 340 (shown in FIG. 3). It is understood that FIG. 4A illustrates one example configuration of fiber-based laser source 400. Laser source 400 can have many other configurations using different combinations of one or more components shown in FIG. 4 A and / or other components not shown in FIG. 4 A (e.g., other components such as power supplies, lens(es), filters, splitters, combiners, etc.).

[0065] In some variations, fiber-based laser source 400 can be controlled (e.g., by control circuitry 350) to produce pulses of different amplitudes based on the fiber gain profile of the fiber used in fiber-based laser source 400. Communication path 312 couples fiber-based laser source 400 to control circuitry 350 (shown in FIG. 3) so that components of fiber-based laser source 400 can be controlled by or otherwise communicate with control circuitry 350.Alternatively, fiber-based laser source 400 may include its own dedicated controller. Instead of control circuitry 350 communicating directly with components of fiber-based laser source 400, a dedicated controller of fiber-based laser source 400 communicates with control circuitry 350 and controls and / or communicates with the components of fiber-based laser source 400. Fiber-based laser source 400 can also include other components not shown, such as one or more power connectors, power supplies, and / or power lines.

[0066] FIG. 4B is a block diagram illustrating an example semiconductor-based laser source 440. Semiconductor-based laser source 440 is an example of light source 310 depicted in FIG. 3. In the example shown in FIG. 4B, laser source 440 is a Vertical-Cavity Surface-Emitting Laser (VCSEL), which is a type of semiconductor laser diode with a distinctive structure that allows it to emit light vertically from the surface of the chip, rather than through the edge of the chip like the edge-emitting laser (EEL) diodes. VCSELs have advantages like high-speed operation and easy integration into semiconductor devices. FIG. 4B shows a cross-sectional view of an example VCSEL 440. In this example, the VCSEL 440 includes a metal contact layer 442, an upper Bragg reflector 444, an active region 446, a lower Bragg reflector 448, a substrate 450, and another metal contact 452. In the VCSEL 440, the metal contacts 442 and 452 are for making electrical contacts so that electrical current and / or voltage can be provided to VCSEL 440 for generating laser light. The substrate layer 450 is a semiconductor substrate, which can be, for example, a gallium arsenide (GaAs) substrate. VCSEL 440 uses a laser resonator, which includes two distributed Bragg reflector (DBR) reflectors (i.e., upper Bragg reflector 444 and lower Bragg reflector 448) with an active region 446 sandwiched between the DBR reflectors. The active region 446 includes, for example, one or more quantum wells for the laser light generation. The planar DBR-reflectors can be mirrors having layers with alternating high and low refractive indices. Each layer has a thickness of a quarter of the laser wavelength in the material, yielding intensity reflectivities above e.g., 99%. High reflectivity mirrors in VCSELs can balance the short axial length of the gain region. In one example of VCSEL 440, the upper and lower DBR reflectors 444 and 448 can be doped as p-type and n-type materials, forming a diode junction. In another example, the p-type and n-type regions may be embedded between the reflectors, requiring a more complex semiconductor process to make electrical contact to the active region, but eliminating electrical power loss in the DBR structure. The active region 446 is sandwiched between the DBR reflectors 444 and 448 of the VCSEL 440. The active region iswhere the laser light generation occurs. The active region 446 typically has a quantum well or quantum dot structure, which contains the gain medium responsible for light amplification. When an electric current is applied to the active region 446, it generates photons by stimulated emission. The distance between the upper and lower DBR reflectors 444 and 448 defines the cavity length of the VCSEL 440. The cavity length in turn determines the wavelength of the emitted light and influences the laser's performance characteristics. When an electrical current is applied to the VCSEL 440, it generates light that bounces between the DBR reflectors 444 and 448 and exits the VCSEL 440 through, for example, the lower DBR reflector 448, producing a highly coherent and vertically emitted laser beam 454. VCSEL 440 can provide an improved beam quality, low threshold current, and the ability to produce single-mode or multi-mode output.

[0067] In some variations, VCSEL 440 can be controlled (e.g., by control circuitry 350) to produce pulses of different amplitudes. Communication path 312 couples VCSEL 440 to control circuitry 350 (shown in FIG. 3) so that components of VCSEL 440 can be controlled by or otherwise communicate with control circuitry 350. Alternatively, VCSEL 440 may include its own dedicated controller. Instead of control circuitry 350 communicating directly with components of VCSEL 400, a dedicated controller of VCSEL 440 communicates with control circuitry 350 and controls and / or communicates with the components of VCSEL 440. VCSEL 440 can also include other components not shown, such as one or more power connectors, power supplies, and / or power lines.

[0068] VCSEL 440 can be used to generate laser pulses or continuous wave (CW) lasers. To generate laser pulses, control circuitry 350 modulates the current supplied to the VCSEL 440. By rapidly turning the supply current on and off, pulses of laser light can be generated. The duration, repetition rate, and shape of the pulses can be controlled by adjusting the modulation parameters. As another example, VCSEL 440 can also be a mode-locked VCSEL that uses a combination of current modulation and optical feedback to obtain ultra-short pulses. The mode-locked VCSEL may also be controlled to synchronize the phases of the laser modes to produce very short and high-intensity pulses. As another example, VCSEL 440 can use Q-Switching techniques, which includes an optical switch in the laser cavity, temporarily blocking the lasing action and allows energy to build up in the cavity. When the switch is opened, a high-intensity pulse is emitted. As another example, VCSEL 440 can also have external modulation performed by an externalmodulator (not shown), such as an electro-optic or acousto-optic modulator. The external modulation can be used in combination with the VCSEL itself to create pulsed output. The external modulator can be used to control the pulse duration and repetition rate. The type of VCSEL used as at least a part of light source 310 depends on the application and the required pulse characteristics, such as pulse duration, repetition rate, and peak power.

[0069] Referencing FIG. 3, typical operating wavelengths of light source 310 comprise, for example, about 850 nm, about 905 nm, about 940 nm, about 1064 nm, and about 1550 nm. For laser safety, the upper limit of maximum usable laser power is set by the U.S. FDA (U.S. Food and Drug Administration) regulations. The optical power limit at 1550 nm wavelength is much higher than those of the other aforementioned wavelengths. Further, at 1550 nm, the optical power loss in a fiber is low. There characteristics of the 1550 nm wavelength make it more beneficial for long-range LiDAR applications. The amount of optical power output from light source 310 can be characterized by its peak power, average power, pulse energy, and / or the pulse energy density. The peak power is the ratio of pulse energy to the width of the pulse (e.g., full width at half maximum or FWHM). Thus, a smaller pulse width can provide a larger peak power for a fixed amount of pulse energy. A pulse width can be in the range of nanosecond or picosecond. The average power is the product of the energy of the pulse and the pulse repetition rate (PRR). As described in more detail below, the PRR represents the frequency of the pulsed laser light. In general, the smaller the time interval between the pulses, the higher the PRR. The PRR typically corresponds to the maximum range that a LiDAR system can measure. Light source 310 can be configured to produce pulses at high PRR to meet the desired number of data points in a point cloud generated by the LiDAR system. Light source 310 can also be configured to produce pulses at medium or low PRR to meet the desired maximum detection distance. Wall plug efficiency (WPE) is another factor to evaluate the total power consumption, which may be a useful indicator in evaluating the laser efficiency. For example, as shown in FIG. 1, multiple LiDAR systems may be attached to a vehicle, which may be an electrical -powered vehicle or a vehicle otherwise having limited fuel or battery power supply. Therefore, high WPE and intelligent ways to use laser power are often among the important considerations when selecting and configuring light source 310 and / or designing laser delivery systems for vehicle-mounted LiDAR applications.

[0070] It is understood that the above descriptions provide non-limiting examples of a light source 310. Light source 310 can be configured to include many other types of light sources (e.g., laser diodes, short-cavity fiber lasers, solid-state lasers, and / or tunable external cavity diode lasers) that are configured to generate one or more light signals at various wavelengths. In some examples, light source 310 comprises amplifiers (e.g., pre-amplifiers and / or booster amplifiers), which can be a doped optical fiber amplifier, a solid-state bulk amplifier, and / or a semiconductor optical amplifier. The amplifiers are configured to receive and amplify light signals with desired gains.

[0071] With reference back to FIG. 3, LiDAR system 300 further comprises a transmitter 320. Light source 310 provides laser light (e.g., in the form of a laser beam) to transmitter 320. The laser light provided by light source 310 can be amplified laser light with a predetermined or controlled wavelength, pulse repetition rate, and / or power level. Transmitter 320 receives the laser light from light source 310 and transmits the laser light to steering mechanism 340 with low divergence. In some embodiments, transmitter 320 can include, for example, optical components (e.g., lens, fibers, mirrors, etc.) for transmitting one or more laser beams to a field-of-view (FOV) directly or via steering mechanism 340. While FIG. 3 illustrates transmitter 320 and steering mechanism 340 as separate components, they may be combined or integrated as one system in some embodiments. Steering mechanism 340 is described in more detail below.

[0072] Laser beams provided by light source 310 may diverge as they travel to transmitter 320. Therefore, transmitter 320 often comprises a collimating lens or a lens group configured to collect the diverging laser beams and produce more parallel optical beams with reduced or minimum divergence. The collimated optical beams can then be further directed through various optics such as mirrors and lens. A collimating lens may be, for example, a single plano-convex lens or a lens group. The collimating lens can be configured to achieve any desired properties such as the beam diameter, divergence, numerical aperture, focal length, or the like. A beam propagation ratio or beam quality factor (also referred to as the M2factor) is used for measurement of laser beam quality. In many LiDAR applications, it is important to have good laser beam quality in the generated transmitting laser beam. The M2factor represents a degree of variation of a beam from an ideal Gaussian beam. Thus, the M2factor reflects how well a collimated laser beam can be focused on a small spot, or how well a divergent laser beam can becollimated. Therefore, light source 310 and / or transmitter 320 can be configured to meet, for example, a scan resolution requirement while maintaining the desired M2factor.

[0073] One or more of the light beams provided by transmitter 320 are scanned by steering mechanism 340 to a FOV. Steering mechanism 340 scans light beams in multiple dimensions (e.g., in both the horizontal and vertical dimension) to facilitate LiDAR system 300 to map the environment by generating a 3D point cloud. A horizontal dimension can be a dimension that is parallel to the horizon or a surface associated with the LiDAR system or a vehicle (e.g., a road surface). A vertical dimension is perpendicular to the horizontal dimension (i.e., the vertical dimension forms a 90-degree angle with the horizontal dimension). Steering mechanism 340 will be described in more detail below. The laser light scanned to an FOV may be scattered or reflected by an object in the FOV. At least a portion of the scattered or reflected light forms return light that returns to LiDAR system 300. FIG. 3 further illustrates an optical receiver and light detector 330 configured to receive the return light. Optical receiver and light detector 330 comprises an optical receiver that is configured to collect the return light from the FOV. The optical receiver can include optics (e.g., lens, fibers, mirrors, etc.) for receiving, redirecting, focusing, amplifying, and / or filtering return light from the FOV. For example, the optical receiver often includes a collection lens (e.g., a single plano-convex lens or a lens group) to collect and / or focus the collected return light onto a light detector.

[0074] A light detector detects the return light focused by the optical receiver and generates current and / or voltage signals proportional to the incident intensity of the return light. Based on such current and / or voltage signals, the depth information of the object in the FOV can be derived. One example method for deriving such depth information is based on the direct TOF (time of flight), which is described in more detail below. A light detector may be characterized by its detection sensitivity, quantum efficiency, detector bandwidth, linearity, signal to noise ratio (SNR), overload resistance, interference immunity, etc. Based on the applications, the light detector can be configured or customized to have any desired characteristics. For example, optical receiver and light detector 330 can be configured such that the light detector has a large dynamic range while having a good linearity. The light detector linearity indicates the detector’s capability of maintaining linear relationship between input optical signal power and the detector’s output. A detector having good linearity can maintain a linear relationship over a large dynamic input optical signal range.

[0075] To achieve desired detector characteristics, configurations or customizations can be made to the light detector’s structure and / or the detector’s material system. Various detector structures can be used for a light detector. For example, a light detector structure can be a PIN based structure, which has an undoped intrinsic semiconductor region (i.e., an “i” region) between a p- type semiconductor and an n-type semiconductor region. Other light detector structures comprise, for example, an APD (avalanche photodiode) based structure, a PMT (photomultiplier tube) based structure, a SiPM (Silicon photomultiplier) based structure, a SPAD (single-photon avalanche diode) based structure, and / or quantum wires. For material systems used in a light detector, Si, InGaAs, and / or Si / Ge based materials can be used. It is understood that many other detector structures and / or material systems can be used in optical receiver and light detector 330.

[0076] A light detector (e.g., an APD based detector) may have an internal gain such that the input signal is amplified when generating an output signal. However, noise may also be amplified due to the light detector’s internal gain. Common types of noise include signal shot noise, dark current shot noise, thermal noise, and amplifier noise. In some embodiments, optical receiver and light detector 330 may include a pre-amplifier that is a low noise amplifier (LNA). In some embodiments, the pre-amplifier may also include a transimpedance amplifier (TIA), which converts a current signal to a voltage signal. For a linear detector system, input equivalent noise or noise equivalent power (NEP) measures how sensitive the light detector is to weak signals. Therefore, they can be used as indicators of the overall system performance. For example, the NEP of a light detector specifies the power of the weakest signal that can be detected and therefore it in turn specifies the maximum range of a LiDAR system. It is understood that various light detector optimization techniques can be used to meet the requirement of LiDAR system 300. Such optimization techniques may include selecting different detector structures, materials, and / or implementing signal processing techniques (e.g., filtering, noise reduction, amplification, or the like). For example, in addition to, or instead of, using direct detection of return signals (e.g., by using ToF), coherent detection can also be used for a light detector. Coherent detection allows for detecting amplitude and phase information of the received light by interfering the received light with a local oscillator. Coherent detection can improve detection sensitivity and noise immunity.

[0077] FIG. 3 further illustrates that LiDAR system 300 comprises steering mechanism 340. As described above, steering mechanism 340 directs light beams from transmitter 320 to scan anFOV in multiple dimensions. A steering mechanism is also referred to as a raster mechanism, a scanning mechanism, or simply a light scanner. Scanning light beams in multiple directions (e.g., in both the horizontal and vertical directions) facilitates a LiDAR system to map the environment by generating an image or a 3D point cloud. A steering mechanism can be based on mechanical scanning and / or solid-state scanning. Mechanical scanning uses rotating mirrors to steer the laser beam or physically rotate the LiDAR transmitter and receiver (collectively referred to as transceiver) to scan the laser beam. Solid-state scanning directs the laser beam to various positions through the FOV without mechanically moving any macroscopic components such as the transceiver. Solid-state scanning mechanisms include, for example, optical phased arrays based steering and flash LiDAR based steering. In some embodiments, because solid- state scanning mechanisms do not physically move macroscopic components, the steering performed by a solid-state scanning mechanism may be referred to as effective steering. A LiDAR system using solid-state scanning may also be referred to as a non-mechanical scanning or simply non-scanning LiDAR system (a flash LiDAR system is an example non-scanning LiDAR system).

[0078] Steering mechanism 340 can be used with a transceiver (e.g., transmitter 320 and optical receiver and light detector 330) to scan the FOV for generating an image or a 3D point cloud. As an example, to implement steering mechanism 340, a two-dimensional mechanical scanner can be used with a single-point or several single-point transceivers. A single-point transceiver transmits a single light beam or a small number of light beams (e.g., 2-8 beams) to the steering mechanism. A two-dimensional mechanical steering mechanism comprises, for example, polygon mirror(s), oscillating mirror(s), rotating prism(s), rotating tilt mirror surface(s), singleplane or multi-plane mirror(s), or a combination thereof. In some embodiments, steering mechanism 340 may include non-mechanical steering mechanism(s) such as solid-state steering mechanism(s). For example, steering mechanism 340 can be based on tuning wavelength of the laser light combined with refraction effect, and / or based on reconfigurable grating / phase array. In some embodiments, steering mechanism 340 can use a single scanning device to achieve two- dimensional scanning or multiple scanning devices combined to realize two-dimensional scanning.

[0079] As another example, to implement steering mechanism 340, a one-dimensional mechanical scanner can be used with an array or a large number of single-point transceivers.Specifically, the transceiver array can be mounted on a rotating platform to achieve 360-degree horizontal field of view. Alternatively, a static transceiver array can be combined with the onedimensional mechanical scanner. A one-dimensional mechanical scanner comprises polygon mirror(s), oscillating mirror(s), rotating prism(s), rotating tilt mirror surface(s), or a combination thereof, for obtaining a forward-looking horizontal field of view. Steering mechanisms using mechanical scanners can provide robustness and reliability in high volume production for automotive applications.

[0080] As another example, to implement steering mechanism 340, a two-dimensional transceiver can be used to generate a scan image or a 3D point cloud directly. In some embodiments, a stitching or micro shift method can be used to improve the resolution of the scan image or the field of view being scanned. For example, using a two-dimensional transceiver, signals generated at one direction (e.g., the horizontal direction) and signals generated at the other direction (e.g., the vertical direction) may be integrated, interleaved, and / or matched to generate a higher or full resolution image or 3D point cloud representing the scanned FOV.

[0081] Some implementations of steering mechanism 340 comprise one or more optical redirection elements (e.g., mirrors or lenses) that steer return light signals (e.g., by rotating, vibrating, or directing) along a receive path to direct the return light signals to optical receiver and light detector 330. The optical redirection elements that direct light signals along the transmitting and receiving paths may be the same components (e.g., shared), separate components (e.g., dedicated), and / or a combination of shared and separate components. This means that in some cases the transmitting and receiving paths are different although they may partially overlap (or in some cases, substantially overlap or completely overlap).

[0082] With reference still to FIG. 3, LiDAR system 300 further comprises control circuitry 350. Control circuitry 350 can be configured and / or programmed to control various parts of the LiDAR system 300 and / or to perform signal processing. In a typical system, control circuitry 350 can be configured and / or programmed to perform one or more control operations including, for example, controlling light source 310 to obtain the desired laser pulse timing, the pulse repetition rate, and power; controlling steering mechanism 340 (e.g., controlling the speed, direction, and / or other parameters) to scan the FOV and maintain pixel registration and / or alignment; controlling optical receiver and light detector 330 (e.g., controlling the sensitivity,noise reduction, filtering, and / or other parameters) such that it is an optimal state; and monitoring overall system health / status for functional safety (e.g., monitoring the laser output power and / or the steering mechanism operating status for safety).

[0083] Control circuitry 350 can also be configured and / or programmed to perform signal processing to the raw data generated by optical receiver and light detector 330 to derive distance and reflectance information, and perform data packaging and communication to vehicle perception and planning system 220 (shown in FIG. 2). For example, control circuitry 350 determines the time it takes from transmitting a light pulse until a corresponding return light pulse is received; determines when a return light pulse is not received for a transmitted light pulse; determines the direction (e.g., horizontal and / or vertical information) for a transmitted / retum light pulse; determines the estimated range in a particular direction; derives the reflectivity of an object in the FOV, and / or determines any other type of data relevant to LiDAR system 300.

[0084] LiDAR system 300 can be disposed in a vehicle, which may operate in many different environments including hot or cold weather, rough road conditions that may cause intense vibration, high or low humidities, dusty areas, etc. Therefore, in some embodiments, optical and / or electronic components of LiDAR system 300 (e.g., optics in transmitter 320, optical receiver and light detector 330, and steering mechanism 340) are disposed and / or configured in such a manner to maintain long term mechanical and optical stability. For example, components in LiDAR system 300 may be secured and sealed such that they can operate under all conditions a vehicle may encounter. As an example, an anti-moisture coating and / or hermetic sealing may be applied to optical components of transmitter 320, optical receiver and light detector 330, and steering mechanism 340 (and other components that are susceptible to moisture). As another example, housing(s), enclosure(s), fairing(s), and / or window can be used in LiDAR system 300 for providing desired characteristics such as hardness, ingress protection (IP) rating, selfcleaning capability, resistance to chemical and resistance to impact, or the like. In addition, efficient and economical methodologies for assembling LiDAR system 300 may be used to meet the LiDAR operating requirements while keeping the cost low.

[0085] It is understood by a person of ordinary skill in the art that FIG. 3 and the above descriptions are for illustrative purposes only, and a LiDAR system can include other functionalunits, blocks, or segments, and can include variations or combinations of these above functional units, blocks, or segments. For example, LiDAR system 300 can also include other components not depicted in FIG. 3, such as power buses, power supplies, LED indicators, switches, etc. Additionally, other connections among components may be present, such as a direct connection between light source 310 and optical receiver and light detector 330 so that light detector 330 can accurately measure the time from when light source 310 transmits a light pulse until light detector 330 detects a return light pulse.

[0086] These components shown in FIG. 3 are coupled together using communications paths 312, 314, 322, 332, 342, 352, 362, and 372. These communications paths represent communication (bidirectional or unidirectional) among the various LiDAR system components but need not be physical components themselves. While the communications paths can be implemented by one or more electrical wires, buses, or optical fibers, the communication paths can also be wireless channels or open-air optical paths so that no physical communication medium is present. For example, in one example LiDAR system, communication path 314 includes one or more optical fibers; communication path 352 represents an optical path; and communication paths 312, 322, 342, and 362 are all electrical wires that carry electrical signals. The communication paths can also include more than one of the above types of communication mediums (e.g., they can include an optical fiber and an optical path, or one or more optical fibers and one or more electrical wires).

[0087] As described above, some LiDAR systems use the time-of-flight (ToF) of light signals (e.g., light pulses) to determine the distance to objects in a light path. For example, with reference to FIG. 5A, an example LiDAR system 500 includes a laser light source (e.g., a fiber laser), a steering mechanism (e.g., a system of one or more moving mirrors), and a light detector (e.g., a photodetector with one or more optics). LiDAR system 500 can be implemented using, for example, LiDAR system 300 described above. LiDAR system 500 transmits a light pulse 502 along light path 504 as determined by the steering mechanism of LiDAR system 500. In the depicted example, light pulse 502, which is generated by the laser light source, is a short pulse of laser light. Further, the signal steering mechanism of the LiDAR system 500 is a pulsed-signal steering mechanism. However, it should be appreciated that LiDAR systems can operate by generating, transmitting, and detecting light signals that are not pulsed and derive ranges to an object in the surrounding environment using techniques other than time-of-flight. For example,some LiDAR systems use frequency modulated continuous waves (i.e., “FMCW”). It should be further appreciated that any of the techniques described herein with respect to time-of-flight based systems that use pulsed signals also may be applicable to LiDAR systems that do not use one or both of these techniques.

[0088] Referring back to FIG. 5A (e.g., illustrating a time-of-flight LiDAR system that uses light pulses), when light pulse 502 reaches object 506, light pulse 502 scatters or reflects to form a return light pulse 508. Return light pulse 508 may return to system 500 along light path 510. The time from when transmitted light pulse 502 leaves LiDAR system 500 to when return light pulse 508 arrives back at LiDAR system 500 can be measured (e.g., by a processor or other electronics, such as control circuitry 350, within the LiDAR system). This time-of-flight combined with the knowledge of the speed of light can be used to determine the range / di stance from LiDAR system 500 to the portion of object 506 where light pulse 502 scattered or reflected.

[0089] By directing many light pulses, as depicted in FIG. 5B, LiDAR system 500 scans the external environment (e.g., by directing light pulses 502, 522, 526, 530 along light paths 504, 524, 528, 532, respectively). As depicted in FIG. 5C, LiDAR system 500 receives return light pulses 508, 542, 548 (which correspond to transmitted light pulses 502, 522, 530, respectively). Return light pulses 508, 542, and 548 are formed by scattering or reflecting the transmitted light pulses by one of objects 506 and 514. Return light pulses 508, 542, and 548 may return to LiDAR system 500 along light paths 510, 544, and 546, respectively. Based on the direction of the transmitted light pulses (as determined by LiDAR system 500) as well as the calculated range from LiDAR system 500 to the portion of objects that scatter or reflect the light pulses (e.g., the portions of objects 506 and 514), the external environment within the detectable range (e.g., the field of view between path 504 and 532, inclusively) can be precisely mapped or plotted (e.g., by generating a 3D point cloud or images).

[0090] If a corresponding light pulse is not received for a particular transmitted light pulse, then LiDAR system 500 may determine that there are no objects within a detectable range of LiDAR system 500 (e.g., an object is beyond the maximum scanning distance of LiDAR system 500). For example, in FIG. 5B, light pulse 526 may not have a corresponding return light pulse (as illustrated in FIG. 5C) because light pulse 526 may not produce a scattering event along its transmission path 528 within the predetermined detection range. LiDAR system 500, or anexternal system in communication with LiDAR system 500 (e g., a cloud system or service), can interpret the lack of return light pulse as no object being disposed along light path 528 within the detectable range of LiDAR system 500.

[0091] In FIG. 5B, light pulses 502, 522, 526, and 530 can be transmitted in any order, serially, in parallel, or based on other timings with respect to each other. Additionally, while FIG. 5B depicts transmitted light pulses as being directed in one dimension or one plane (e.g., the plane of the paper), LiDAR system 500 can also direct transmitted light pulses along other dimension(s) or plane(s). For example, LiDAR system 500 can also direct transmitted light pulses in a dimension or plane that is perpendicular to the dimension or plane shown in FIG. 5B, thereby forming a 2-dimensional transmission of the light pulses. This 2-dimensional transmission of the light pulses can be point-by-point, line-by-line, all at once, or in some other manner. That is, LiDAR system 500 can be configured to perform a point scan, a line scan, a one-shot without scanning, or a combination thereof. A point cloud or image from a 1-dimensional transmission of light pulses (e.g., a single horizontal line) can generate 2- dimensional data (e.g., (1) data from the horizontal transmission direction and (2) the range or distance to objects). Similarly, a point cloud or image from a 2-dimensional transmission of light pulses can generate 3-dimensional data (e.g., (1) data from the horizontal transmission direction, (2) data from the vertical transmission direction, and (3) the range or distance to objects). In general, a LiDAR system performing an / / -dimensional transmission of light pulses generates (ii+ 1 ) dimensional data. This is because the LiDAR system can measure the depth of an object or the range / di stance to the object, which provides the extra dimension of data. Therefore, a 2D scanning by a LiDAR system can generate a 3D point cloud for mapping the external environment of the LiDAR system.

[0092] The density of a point cloud refers to the number of measurements (data points) per area performed by the LiDAR system. A point cloud density relates to the LiDAR scanning resolution. Typically, a larger point cloud density, and therefore a higher resolution, is desired at least for the region of interest (ROI). The density of points in a point cloud or image generated by a LiDAR system is equal to the number of pulses divided by the field of view. In some embodiments, the field of view can be fixed. Therefore, to increase the density of points generated by one set of transmission-receiving optics (or transceiver optics), the LiDAR system may need to generate a pulse more frequently. In other words, a light source in the LiDARsystem may have a higher pulse repetition rate (PRR). On the other hand, by generating and transmitting pulses more frequently, the farthest distance that the LiDAR system can detect may be limited. For example, if a return signal from a distant object is received after the system transmits the next pulse, the return signals may be detected in a different order than the order in which the corresponding signals are transmitted, thereby causing ambiguity if the system cannot correctly correlate the return signals with the transmitted signals.

[0093] To illustrate, consider an example LiDAR system that can transmit laser pulses with a pulse repetition rate between 500 kHz and 1 MHz. Based on the time it takes for a pulse to return to the LiDAR system and to avoid mix-up of return pulses from consecutive pulses in a typical LiDAR design, the farthest distance the LiDAR system can detect may be 300 meters and 150 meters for 500 kHz and 1 MHz, respectively. The density of points of a LiDAR system with 500 kHz repetition rate is half of that with 1 MHz. Thus, this example demonstrates that, if the system cannot correctly correlate return signals that arrive out of order, increasing the repetition rate from 500 kHz to 1 MHz (and thus improving the density of points of the system) may reduce the detection range of the system. Various techniques are used to mitigate the tradeoff between higher PRR and limited detection range. For example, multiple wavelengths can be used for detecting objects in different ranges. Optical and / or signal processing techniques (e.g., pulse encoding techniques) are also used to correlate between transmitted and return light signals.

[0094] Various systems, apparatus, and methods described herein may be implemented using digital circuitry, or using one or more computers using well-known computer processors, memory units, storage devices, computer software, and other components. Typically, a computer includes a processor for executing instructions and one or more memories for storing instructions and data. A computer may also include, or be coupled to, one or more mass storage devices, such as one or more magnetic disks, internal hard disks and removable disks, magnetooptical disks, optical disks, etc.

[0095] Various systems, apparatus, and methods described herein may be implemented using computers operating in a client-server relationship. Typically, in such a system, the client computers are located remotely from the server computers and interact via a network. The client-server relationship may be defined and controlled by computer programs running on the respective client and server computers. Examples of client computers can include desktopcomputers, workstations, portable computers, cellular smartphones, tablets, or other types of computing devices.

[0096] Various systems, apparatus, and methods described herein may be implemented using a computer program product tangibly embodied in an information carrier, e.g., in a non-transitory machine-readable storage device, for execution by a programmable processor; and the method processes and steps described herein, including one or more of the steps of at least some of the FIGS. 1-12, may be implemented using one or more computer programs that are executable by such a processor. A computer program is a set of computer program instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0097] A high-level block diagram of an example apparatus that may be used to implement systems, apparatus and methods described herein is illustrated in FIG. 6. Apparatus 600 comprises a processor 610 operatively coupled to a persistent storage device 620 and a main memory device 630. Processor 610 controls the overall operation of apparatus 600 by executing computer program instructions that define such operations. The computer program instructions may be stored in persistent storage device 620, or other computer-readable medium, and loaded into main memory device 630 when execution of the computer program instructions is desired. For example, processor 610 may be used to implement one or more components and systems described herein, such as control circuitry 350 (shown in FIG. 3), vehicle perception and planning system 220 (shown in FIG. 2), and vehicle control system 280 (shown in FIG. 2). Thus, the method steps of at least some of FIGS. 1-12 can be defined by the computer program instructions stored in main memory device 630 and / or persistent storage device 620 and controlled by processor 610 executing the computer program instructions. For example, the computer program instructions can be implemented as computer executable code programmed by one skilled in the art to perform an algorithm defined by the method steps discussed herein in connection with at least some of FIGS. 1-12. Accordingly, by executing the computer program instructions, the processor 610 executes an algorithm defined by the method steps of these aforementioned figures. Apparatus 600 also includes one or more network interfaces 680 forcommunicating with other devices via a network. Apparatus 600 may also include one or more input / output devices 690 that enable user interaction with apparatus 600 (e.g., display, keyboard, mouse, speakers, buttons, etc.).

[0098] Processor 610 may include both general and special purpose microprocessors and may be the sole processor or one of multiple processors of apparatus 600. Processor 610 may comprise one or more central processing units (CPUs), and one or more graphics processing units (GPUs), which, for example, may work separately from and / or multi-task with one or more CPUs to accelerate processing, e.g., for various image processing applications described herein.Processor 610, persistent storage device 620, and / or main memory device 630 may include, be supplemented by, or incorporated in, one or more application-specific integrated circuits (ASICs) and / or one or more field programmable gate arrays (FPGAs).

[0099] Persistent storage device 620 and main memory device 630 each comprise a tangible non-transitory computer readable storage medium. Persistent storage device 620, and main memory device 630, may each include high-speed random access memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), double data rate synchronous dynamic random access memory (DDR RAM), or other random access solid state memory devices, and may include non-volatile memory, such as one or more magnetic disk storage devices such as internal hard disks and removable disks, magneto-optical disk storage devices, optical disk storage devices, flash memory devices, semiconductor memory devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), digital versatile disc read-only memory (DVD-ROM) disks, or other non-volatile solid state storage devices.

[0100] Input / output devices 690 may include peripherals, such as a printer, scanner, display screen, etc. For example, input / output devices 690 may include a display device such as a cathode ray tube (CRT), plasma or liquid crystal display (LCD) monitor for displaying information to a user, a keyboard, and a pointing device such as a mouse or a trackball by which the user can provide input to apparatus 600.

[0101] Any or all of the functions of the systems and apparatuses discussed herein may be performed by processor 610, and / or incorporated in, an apparatus or a system such as LiDARsystem 300. Further, LiDAR system 300 and / or apparatus 600 may utilize one or more neural networks or other deep-learning techniques performed by processor 610 or other systems or apparatuses discussed herein.

[0102] One skilled in the art will recognize that an implementation of an actual computer or computer system may have other structures and may contain other components as well, and that FIG. 6 is a high-level representation of some of the components of such a computer for illustrative purposes.

[0103] FIG. 7 is a block diagram illustrating an example light receiver 700 in accordance with various embodiments. Light receiver 700 may include one or more components of optical receiver and light detector 330 described above in connection with FIG. 3. For instance, light receiver 700 may include a plurality of light detectors forming a light detector array 710. In some examples, light receiver 700 may also include a part of control circuitry 350 described above in connection with FIG. 3. As shown in FIG. 7, light receiver 700 may include a matrix switch device 730 and a sampler 750. Matrix switch device 730 and sampler 750 may be included in control circuitry 350 shown in FIG. 3 above.

[0104] Beginning with light detector array 710, it includes a plurality of light detectors configured to receive light from an FOV of a LiDAR system and generate a plurality of electrical outputs 712. The light from the FOV may include return light generated based on scattering or reflecting of the transmission light from the LiDAR system. The electrical outputs 712 can be electrical analog signals and are provided to matrix switch device 730. Matrix switch device 730 is configurable to have a plurality of different switch settings. In some examples, the particular switch setting used for matrix switch device 730 depends on at least one of detection results or operational conditions of the LiDAR system. As described below, matrix switch device 730 can include a plurality of electrical switches controlled based on different switch settings. Each of the electrical switches can be controlled to connect or disconnect (e.g., open or close the switch) certain inputs of the matrix switch device 730, to or from, the channels 740. Therefore, the operation of the electrical switches can connect one or more electrical outputs of any light detector or group of light detectors to a particular channel 740. Matrix switch device 730 therefore form switched outputs based on a particular switch setting using plurality of electrical outputs from the light detector array 710. Channels 740 receive the switched outputs from thematrix switch device 730 and provide them to sampler 750. The switched outputs can include electrical analog signals, which sampler 750 converts to digital outputs 760. As shown in FIG. 7, the matrix switch device 730 may be controlled by control circuitry (like circuitry 350). For instance, control circuitry 350 can control the matrix switch device 730 to have a particular switch setting. The light detector array 710, matrix switch device 730, and sampler 750 are described in greater detail below. The digital outputs 760 from sampler 750 can be provided, e.g., to control circuitry 350 or another processor, for downstream processing, such as for creating a point cloud.

[0105] FIGs. 8A-8B are block diagrams illustrating example light detectors arranged in an array, in accordance with various embodiments. FIG. 8 A illustrates a plurality of light detectors 810 arranged on a surface 800 of a light receiver (e.g., light receiver 700). Light detectors 810 in the example shown in FIG. 8 A form an 8x1 array, such that the detectors are aligned in one direction (horizontal, vertical, or any other one direction). FIG. 8B illustrates a plurality of light detectors 820 arranged on a surface 800 of a light receiver (e.g., light receiver 700). Light detectors 820 in the example shown in FIG. 8B form an 4x2 array, such that the detectors are aligned in two directions (e.g., both the horizonal and vertical directions). It is understood that FIGs. 8A and 8B only illustrate two examples of arrays of light detectors. In general, a plurality of light detectors in a light receiver (e.g., light receiver 700) can form a ;V-by-A7 array of light detectors, where N and M are both integer numbers. The number N may or may not be equal to the number M. The selection of the numbers A and M can depend on the applications of the LiDAR system, operational conditions, and / or the performance requirements of the LiDAR system. Similarly, the arrangements of the plurality of light detectors can depend on the applications of the LiDAR system, operational conditions, and / or the performance requirements of the LiDAR system.

[0106] Furthermore, the plurality of light detectors (e.g., detectors 810 and 820) may be semiconductor based light detectors, such as SiPM (Silicon Photon Multipliers), APD (Avalanche Photo Diodes), etc. The plurality of light detectors may each be an individual chip mounted onto a circuit board (e.g., a printed circuit board), or may be integrated into a single chip or single chip package. The plurality of light detectors (e.g., detectors 810 and 820) can be arranged on a surface (e.g., surface 800) of the light receiver to receive light. The received light may include return light such as scattered or reflected light based on transmission light of the LiDAR system illuminating one or more objects in the FOV. The light detectors convert thereceived light to electrical signals (e.g., voltage signals or current signals) and provide them as electrical outputs to a matrix switch device.

[0107] FIGs. 9A-9H illustrate example light detectors 910 coupled to a matrix switch device 930 configured to have different switching settings, in accordance with various embodiments. FIG. 9A illustrates a particular switch setting, in which the electrical switches in matrix switch device 930 are configured such that each electrical output 912 from light detectors 910 is directed to a corresponding one of a plurality of channels 940. FIGs. 9B-9D illustrates various switch settings, in which the electrical switches in matrix switch device 930 are configured such that two, four, or eight electrical outputs 912 from light detectors 910, respectively, are combined to form a combined electrical output. The combined electrical output is directed to a designated channel of a plurality of channels 940. FIG. 9E illustrates another particular switch setting, in which the electrical switches in matrix switch device 930 are configured such that not all electrical outputs 912 from the plurality of light detectors 910 are used in forming the switched outputs. FIGs. 9F and 9G illustrate an embodiment where the number of channels is fewer than the number of light detectors. In the embodiment shown in FIGs. 9F and 9G, the channels 940 are configured to sequentially receive the switched outputs formed in multiple switch settings. FIG. 9H illustrates an embodiment in which the number of channels is greater than the number of light detectors. In the embodiment shown in FIG. 9H, the channels are configured to receive, in parallel, the switched outputs formed in multiple switch settings. Each of the embodiments shown in FIGs. 9A-9H is described in greater detail below.

[0108] Beginning with FIG. 9A, a plurality of light detectors 910 convert received light to electrical signals and provide them as electrical outputs 912 to matrix switch device 930. FIG. 9 A and other figures show that the plurality of light detectors 910 are arranged in a 1- dimensional array for illustration purposes. It is understood that the plurality of light detectors can also be arranged in a 2-dimensional array (or even a 3-dimensional array) as described above. As shown in FIG. 9A, matrix switch device 930 includes a plurality of electrical switches denoted by S10, S20, S30, S33, S40, S50, S51, S60, S61, S70, S71, and S72. The electrical switches may be semiconductor transistors-based switches. For instance, they may be implemented by metal-oxide-semiconductor field effect transistors (MOSFETs), bipolar transistors, or other types of transistors.

[0109] The electrical switches of device 930 may form a matrix and therefore device 930 is referred to as a matrix switch device or a matrix switch array. These electrical switches in device 930 can be controlled by control circuitry (e.g., circuitry 350 shown in FIG. 3). The control circuitry can control the switches based on different switch settings. The different switch settings can be generated based on at least one of detection results or operational conditions of the LiDAR system. As one example, different switch settings may be used if detection distances are different. For instance, based on previous distance detection results, the LiDAR system may determine that the objects are located nearby (e.g., within a certain threshold distance). Accordingly, the control circuitry of the LiDAR system configures the matrix switch device 930 to have a particular switch setting. And if the LiDAR system determines that the objects are located far away (e.g., beyond the certain threshold distance), the control circuitry may configure matrix switch device 930 to have another particular switch setting. Using different switch settings, the control circuitry (e.g., circuitry 350) controls the electrical switches of device 930 to segment or combine the electrical outputs 912 from the light detectors 910 depending on, for example, the detection distance. As described above, for a nearby object, the return light received by the light detectors 910 may have a high signal strength. Therefore, the multiple electrical outputs 912 from the light detectors 910 may not need to be combined. In some examples, not all the electrical outputs 912 may be needed (e.g., to avoid saturation of the light receiver) and therefore some of the electrical outputs 912 are not forwarded to channels 940. On the other hand, for a far-away object, the return light may have a low signal strength. Therefore, multiple electrical outputs 912 from the light detectors 910 may be combined to provide greater signal strength, thereby enhancing the detection sensitivity of the light receiver.

[0110] Configuring the matrix switch device 930 to have different switch settings based on the detection distance as described above is one example. In general, the switch settings can be determined based on other detection results including, for example, a detected object reflectivity, detected signal strength from the light detectors, detected signal strength distribution, a detected signa-to-noise ratio (SNR), and / or feedback from a perception system. For instance, if the light receiver has a high SNR, the matrix switch device 930 can have a particular switching setting that has does not combine or combines a fewer number of electrical outputs 912 of the light detectors, and vice versa. Similarly, a high signal strength or high detected object reflectivity may correspond to a switching setting that that does not combine or combines a fewer number ofelectrical outputs 912, and vice versa. The detection results may also include feedback from a perception system (e.g., one or more sub-systems of vehicle perception and planning system 220 shown in FIG. 2). The feedback from the perception system may not be based on results from the LiDAR system, but may also be based on other sensors like cameras, radars sensors, ultrasonic sensors, or other sensors. Depending on the feedback from the perception system, the control circuitry may determine to combine or not combine multiple electrical outputs 912 of the light detectors. The detection results, which can be used to determine the switch settings of device 930, can be obtained by the LiDAR system at a past time point or a current time point. For example, the last and / or the current detection distance can be obtained by the control circuitry (e.g., circuitry 350) and used to determine the switch setting for the next distance detection. In some embodiments, the detection results may be estimated, anticipated, or predicted results at a future time point, such that the control circuitry can set the switch setting ahead of time for improving the light detection performance at the future time point.[0U1] In some embodiments, the matrix switch device 930 can have different switch settings based on operational conditions of the LiDAR system. Such operational conditions may include, for example, a scanning angle of the LiDAR system, a scanning direction of the LiDAR system, a laser power setting, a region-of-interest (ROI) setting, a detection sensitivity setting, and / or a receiving buffer duration / size, and a receiving timing resolution. For example, if the control circuitry determines or anticipates that the scanning angle (current or future) of the LiDAR system is at or below the horizon (e.g., the scanning mechanism 340 looking downward in the vertical direction), it is likely that the LiDAR system scans a near-distance object (e.g., an object that is located within a threshold distance). In this situation, the control circuitry (e.g., circuitry 350) can configure the matrix switch device 930 to have a particular switch setting that does not combine or combines a fewer number of electrical outputs 912 of the light detectors 910. This is because the return light from a near-distance object likely has a stronger signal strength and therefore, combining multiple electrical outputs 912 may not be needed. On the other hand, if the control circuitry determines or anticipates that the scanning angle (current or future) of the LiDAR system is above the horizon, it is likely that the LiDAR system scans a far-away object (e.g., an object located outside of the threshold distance). In this situation, the control circuitry can configure the matrix switch device 930 to have another particular switch setting thatcombines some electrical outputs 912 of the light detectors 910 to provide switched outputs that have greater signal strengths (e g., larger signal amplitude).

[0112] Similarly, the control circuitry can determine that the matrix switch device 930 should have other particular switching settings, depending on other operational conditions of the LiDAR system. For instance, if the laser power setting is high (e.g., higher than a threshold laser power), the control circuitry can configure the matrix switch device 930 to have a particular switch setting that does not combine or combines a fewer number of electrical outputs of the light detectors, and vice versa. If the control circuitry sets a certain scan area of the FOV as a region- of-interest (ROI), it may determine that higher detection sensitivity and / or resolution is required for the ROI. The control circuitry may thus configure the matrix switch device 930 to have a particular switch setting such that the selected electrical outputs 912 corresponding to the light detectors 910 receiving light from the ROI are provided to channels 940 while other electrical outputs 912 may not be provided. In another example, under the particular switch setting, the switch device 930 may combine the selected electrical outputs 912 to improve the detection sensitivity and / or detection resolution for the ROI.

[0113] In some embodiments, the control circuitry may determine whether to combine multiple electrical outputs 912, or the number of electrical outputs 912 to-be-combined, based on a receiving buffer duration / size. For example, if a receiving buffer duration or size is small, the control circuitry may determine to combine a greater numbers of the electrical outputs 912, and / or may determine to perform sequential processing of the electrical outputs 912 (which is described below in greater detail). Conversely, if the receiving buffer duration or size is large, the control circuitry may determine to not combine or combine a fewer number of electrical outputs 912, and / or may determine to perform parallel processing of the electrical outputs 912 (which is described below in greater detail). In some embodiments, the control circuitry may determine whether to combine multiple electrical outputs 912, or the number of electrical outputs 912 to-be-combined, based on a receiving timing resolution. If a receiving timing resolution is high, the control circuitry may determine to combine a larger number of the multiple electrical outputs 912. Conversely, if the receiving timing resolution is low, the control circuitry may determine to not combine, or combine a fewer number of, the multiple electrical outputs 912. If timing resolution high, more return light pulses may be received and correspondingly more electrical outputs are generated. This will likely require more memory or other storage, andtherefore the control circuitry may be required to combine more electrical outputs or more channels to reduce memory requirements.

[0114] FIG. 9A illustrates an example configuration of the electrical switches in a particular switch setting of the switch device 930. In this switching setting as shown in FIG. 9A, the electrical switches of matrix switch device 930 are controlled to direct each electrical output of the plurality of electrical outputs 912 to a corresponding one of the plurality of channels 940. Specifically, each of electrical switches S10, S20, S30, S33, S40, S50, S51, S60, S61, S70, S71, and S72 may have two or more positions. In FIG. 9A, for instance, each of these switches has two positions (e.g., an up position or a down position). Thus, if switch S10 is controlled to be in the up position, it connects the electrical output 01 to channel CO. If switch S10 is controlled to be in the down position, it connects the electrical output 01 to channel C4. Similarly, placing switch S20 in the up position connects the electrical output 02 to channel CO, and placing switch 02 in the down position connects the electrical output 02 to channel C3. In FIG. 9A, all switches are controlled to be at the down positions. In this particular switch setting, each of electrical outputs 912 (i.e., OO, 01, 02, 03, 04, 05, 06, and 07) are connected to a corresponding one of channels CO, C4, C3, C5, Cl, C6, C2, and C7 of channels 940, respectively. The specific correspondence of the electrical outputs 912 to channels 940 are for illustrative purposes only, and it is understood that other correspondence may also be implemented by configuring the electrical switches in matrix switch device 930 differently.

[0115] The particular switching setting shown in FIG. 9A may be determined by the control circuitry (e.g., circuitry 350) based on at least one of the detection results or the operational conditions, as described above. With reference to FIG. 10, for example, the detection results of a LiDAR system 1000 (e.g., substantially the same or similar to system 300) may include a first detected distance 1014 of a first object 1004 located within a threshold distance from the LiDAR system 1000. And the operational conditions of the LiDAR system 1000 may include a scanning angle of the LiDAR system being at or below the horizon 1010). As described above, such detection results and / or the operational conditions may indicate that the LiDAR system 1000 is detecting a nearby object 1004 (e.g., the scanning mechanism of LiDAR system 1000 is looking down to the object 1004). In some embodiments, if the control circuitry determines that the LiDAR system 1000 scans the first object 1004 located within the threshold distance from the LiDAR system 1000 and / or if the scanning angle of the LiDAR system 1000 is at or below thehorizon 1010, the control circuitry may control the matrix switch device 930 to have the particular switch setting as shown in FIG. 9A. That is, the matrix switch device 930 is controlled to direct each electrical output 912 from a light detector 910 to a corresponding one channel 940. The channels and the electrical outputs from the light detectors 910 thus may have a one-to-one relationship. As described above, the return light from a nearby object may have a strong signal strength (e.g., within the dynamic range of the light detector) such that there is no need to combine multiple electrical outputs 912 of several light detectors 910 to improve the detection sensitivity.

[0116] FIG. 9B illustrates another particular switch setting. In FIG. 9B, the light detectors 910 and matrix switch device 930 may be substantially the same as those in FIG. 7 and 9A. The electrical switches in this particular switch setting, however, may be configured differently from the setting shown in FIG. 9A. Specifically, in this switching setting as shown in FIG. 9B, the electrical switches of matrix switch device 930 are controlled to combine two electrical outputs of the plurality of electrical outputs 912 to a corresponding one of the plurality of channels 940. Specifically, in FIG. 9B, switch S10 is placed at the up position, thereby connecting the electrical output 01 to channel CO. Because the channel CO is already connected to electrical output OO, placing switch S10 at the up position combines the electrical outputs OO and 01 to form a combined electrical output OO+Ol . The combined electrical output 00+01 is provided to channel CO.

[0117] FIG. 9B further illustrates that the switches S20, S30, S40, S50, S60, S70, S61, and S71 are placed at the down position; and that switches S10, S51, and S72 are placed at the up position. In this switch setting, channel CO receives the combine electrical outputs 00+01; channel Cl receives the combine electrical outputs 04+05; channel C2 receives the combine electrical outputs 06+07; and channel C3 receives the combine electrical outputs 02+03. Channels C4-C7 are unused, meaning that they do not receive any electrical outputs 912 from light detectors 910. It is understood that the specific correspondence of the electrical outputs 912 to channels 940 shown in FIG. 9B are for illustrative purposes only, and it is understood that other correspondence may also be implemented by configuring the switches in matrix switch device 930 differently.

[0118] FIG. 9C illustrates another particular switch setting. In FIG. 9C, the light detectors 910 and matrix switch device 930 may be substantially the same as those in FIG. 7 and 9A. The electrical switches in this particular switch setting, however, may be configured differently from the settings shown in FIGs. 9A and 9B. Specifically, in this switching setting as shown in FIG. 9C, the electrical switches of matrix switch device 930 are controlled to combine four electrical outputs of the plurality of electrical outputs 912 to a corresponding one of the plurality of channels 940. Specifically, in FIG. 9C, switch S10, S20, and S30 are placed at the up positions, thereby connecting the electrical outputs 01, 02, and 03 to channel CO. Because channel CO is already connected to electrical output OO, placing switches S10, S20, and S30 at the up positions combines the electrical outputs OO, 01, 02, and 03 to form a combined electrical output 00+01+02+03. The combined electrical output 00+01+02+03 is connected to channel CO.

[0119] FIG. 9C further illustrates that the switches S33, S40, S50, S60, S70, and S72 are placed at the down position, and switches S71, S51, and S61 are placed at the up position. In this switch setting, channel Cl receives the combine electrical output 04+05+06+07. Channels C2-C7 are unused, meaning that they do not receive any electrical outputs from light detectors 910. It is understood that the specific correspondence of the electrical outputs 912 to channels 940 shown in FIG. 9C are for illustrative purposes only, and it is understood that other correspondence may also be implemented by configuring the switches in matrix switch device 930 differently.

[0120] FIG. 9D illustrates another particular switch setting. In FIG. 9D, the light detectors 910 and matrix switch device 930 may be substantially the same as those in FIG. 7 and 9A. The electrical switches in this particular switch setting, however, may be configured differently from the settings shown in FIGs. 9A-9C. Specifically, in this switching setting as shown in FIG. 9D, the electrical switches of matrix switch device 930 are controlled to combine eight electrical outputs of the plurality of electrical outputs 912 to a corresponding one of the plurality of channels 940. Specifically, in FIG. 9D, switch S10, S20, S30, S40, S50, S60, and S70 are placed at the up positions, thereby connecting the electrical outputs 01-07 to channel CO. Because the channel CO is already connected to electrical output OO, placing switches S10, S20, S30, S40, S50, S60, and S70 at the up positions combines the electrical outputs 00-07 to form a combined electrical output 00+01+02+03+04+05+06+07. The combined electrical output 00+01+02+03+04+05+06+07 is connected to channel CO.

[0121] FIG. 9D further illustrates that the switches S33, S51, S61 , S71, and S72 are placed at the down positions. In this switch setting, channels C1-C7 are unused, meaning that they do not receive any electrical outputs from light detectors 910. It is understood that the specific correspondence of the electrical outputs 912 to channels 940 shown in FIG. 9D are for illustrative purposes only, and it is understood that other correspondence may also be implemented by configuring the switches in matrix switch device 930 differently.

[0122] FIGs. 9B-9D illustrates several switch settings in which multiple electrical outputs (e.g., 2, 4, or 8) are combined to form combined electrical outputs. Each of the combined electrical outputs is directed to a designated channel 940. As described above, electrical outputs 00-07 from the light detectors 910 are analog electrical signals. Therefore, combining multiple (e g., 2, 4, or 8) electrical outputs combines, or superimposes, the amplitudes of the analog electrical signals. Thus, if each individual light detector 910 only generates a small electrical current due to the weak received return light, combining multiple small electrical currents from multiple light detectors 910 forms a combined electrical current that has a larger amplitude. Such a combined electrical current having a larger amplitude may provide a better SNR and may improve the detection sensitivity. For instance, the electrical output from an individual light detector 910 may be so small in amplitude that it is not detectable (e.g., outside of the dynamic range of the light receiver). But when combining two electrical outputs from two light detectors, the amplitude of the combined electrical output may become detectable (e.g., fall within the dynamic range of the light receiver).

[0123] The particular switching setting shown in FIGs. 9B-9D may be determined by the control circuitry (e.g., circuitry 350) based on at least one of the detection results or the operational conditions, as described above. With reference to FIG. 10, for example, the detection results of the LiDAR system 1000 may include a second detected distance 1012 of a second object 1002 located outside of a threshold distance from the LiDAR system 1000. And the operational conditions of the LiDAR system 1000 may include a scanning angle of the LiDAR system 1000 being above the horizon 1010. As described above, such detection results and / or the operational conditions may indicate that the LiDAR system 1000 is detecting a far-away object (e.g., the scanning mechanism of LiDAR system 1000 is scanning above the horizon 1010 to the object 1002). In some embodiments, if the control circuitry determines that the LiDAR system 1000 scans the second object 1002 located outside of the threshold distance from the LiDAR systemand / or if the scanning angle of the LiDAR system is above the horizon, the control circuitry may control the matrix switch device 930 to have the particular switch setting shown in any one of FIGs. 9B-9D. That is, the matrix switch device 930 is controlled to combine multiple electrical outputs 912 from light detectors 910 to form a combined electrical output and direct it to a designated channel 940. The channels 940 and the electrical outputs 912 of the light detectors 910 thus may have a multiple-to-one relationship (e.g., 2-to-l, 4-to-l, or 8-to-l). As described above, the return light from a far-away object may have a weak signal strength (e.g., outside of the dynamic range of the light detector) such that there is a need to combine multiple electrical outputs of several light detectors to improve the detection sensitivity.

[0124] FIGs. 9E-9H illustrate other example switch settings. For simplicity, the electrical switches (e.g., S10, S20, S30, etc.) in matrix switch device 930 are omitted in FIGs. 9F-9H. They can be substantially the same or similar to those shown in FIGs. 9A-9D. Moreover, a person of ordinary skill in the art would have understood that the control circuitry (e.g., circuitry 350) can configure the electrical switches of device 930 in the manner to obtain the example switch settings shown in FIGs. 9E-9H. FIG. 9E illustrates that in some embodiments, the number of channels 940 may be fewer than or equal to the number of light detectors. For instance, as described above in connection with FIGs. 9A, the number of channels 940 may be eight, same as the number of light detectors or the number of electrical outputs 912. In some examples as shown in FIG. 9E, the number of channels 940 may be four, while the number of light detectors 910 may be eight. In this example of FIG. 9E, channels Cl, C3, C4, and C6 are unused, or do not exist at all. Channels CO, C2, C5, and C7 receive the electrical outputs 02, 03, 04, and 05 of the corresponding light detectors 910. These channels may be referred to as active channels. It is understood that that the active channels may also receive combine electrical outputs depending on the switch settings. For example, active channel CO may receive a combination of electrical outputs O1+O2.

[0125] The particular switch setting shown in FIG. 9E may be determined by the control circuitry based on detection results and / or operational conditions of the LiDAR system. For example, if the control circuitry determines that previous detection results of an area in the FOV do not have sufficient resolution and thus need a higher resolution scan, and / or if the control circuitry determines that there is an ROI to be scanned while the other areas may not need to be scanned or updated, it can control the switch setting of the matrix switch device 930 such thatjust the electrical outputs corresponding to the light detectors that receive the return light from the ROI are directed to the corresponding channels. In FIG. 9E, for instance, the electrical outputs 02-05 from the corresponding light detectors 910 represent the return light received from the ROI, and thus they are directed to the channels Cl, C3, C4, and C6 for further processing. Other electrical outputs may not be directed to the channels. In some examples, if the control circuitry determines that multiple electrical outputs are combined together to form one or more combined electrical outputs, it also determines that not all the channels are needed to receive the combined electrical outputs. The control circuitry can thus determine the switching settings accordingly such that some of the channels are unused or disconnected, (e.g., the switch settings shown in FIGs. 9B-9D).

[0126] FIGs. 9F-9G illustrate another example of changing from a first switch setting to a second switch setting for sequential processing. In some embodiments, the plurality of channels 940 are configured to sequentially receive, from switch device 930, switched outputs formed in multiple switch settings of the plurality of different switch settings. Similar to FIG. 9E described above, in the switch settings shown in FIGs. 9F and 9G, the number of channels 940 may be fewer than the number of light detectors 910 or the electrical outputs 912. For illustration purposes, FIGs. 9F and 9H show that there are four channels (e.g., active channels) that are used to process the switched outputs from the matrix switch device 930, while there are eight electrical outputs 912 from the eight corresponding light detectors 910. Unused channels are omitted from showing in FIGs. 9F and 9H. They may be unused or disconnected channels. A channel may include electrical wires or other transmission lines for conducting analog electrical signals (e.g., current signals and / or voltage signals). In some examples, a channel may also include other electrical components like amplifiers, filters, couplers, repeaters, etc.

[0127] With reference to FIG. 9F, in a first switch setting, matrix switch device 930 may direct four electrical outputs 02-05 to the channels C2-C5, respectively. Therefore, at a first time point, channels C2-C5 receive and process the switched outputs formed based on the four electrical outputs 02-05, respectively. After these switched outputs (e.g., same as the electrical outputs 02-05) are received (and / or processed) by channels C2-C5, the control circuitry (e.g., circuitry 350) changes the first switch setting to a second switch setting as shown in FIG. 9G. In the second switch setting, matrix switch device 930 may direct other four electrical outputs OO, 01, 06, and 07 to the same four channels C2-C5. At this time, channels C2-C5 are available toreceive new data. Thus, at a second time point, channels C2-C5 receive and processes the switched outputs formed based on the four other electrical outputs OO, 01, 06 and 07. In this manner, the matrix switch device 930 can be controlled to switch between different settings while keeping using the same channels 940. The control circuitry thus configures the same set of channels (e.g., C2, C3, C4, and C5) to sequentially receive, from the switching device 930, switched outputs formed in multiple switch settings. The multiple switch settings may be the same or different. The light receiver therefore can perform sequential processing of the electrical outputs from different groups of light detectors. Sequential processing consumes less power and reduces the overall cost. In certain applications where the throughput requirement for the light receiver is low or moderate, sequential processing can be implemented by the control circuitry. Moreover, using fewer channels also reduces crosstalk between the channels 940, because the spacing between neighboring channels can be selected to be sufficiently large and / or because the neighboring channels can be sufficiently shielded.

[0128] Turning to FIG. 9H, in some examples, the number of channels may be greater than the number of light detectors 910 or the electrical outputs 912. As shown in FIG. 9H, for example, the number of light detectors 910 (and the number of the corresponding electrical outputs OO- 07) may be eight, while the number of channels may be 16 (e.g., from C0-C15). When there are a greater number of channels than the number of light detectors, parallel processing of the electrical outputs 912 from the light detectors 910 may be implemented. For example, in some situations, the LiDAR system may not know which switch setting may provide a better detection result. Therefore, the control circuitry of the LiDAR system may configure the matrix switch device 930 to have multiple switch settings. As shown in FIG. 9H, the matrix switch device 930 may have a sufficient number of switches to implement two or more switch settings in parallel. FIG. 9H shows two settings. In a first switch setting, each of the channels C0-C7 receives a corresponding one of the electrical outputs 00-07. In the second switch setting, channel C8 receives a combination of electrical outputs 01 and 02, channel CIO receives a combination of electrical outputs 03 and 04; channel C13 receives a combination of electrical outputs 06 and 07; and other channels C9, Cl 1, C12, C14, and C15 may be unused or disconnected from switch device 930. Thus, in this configuration, matrix switch device 930 has two switch settings in parallel and the channels can receive electrical outputs in the two switch settings in parallel.

[0129] The two switch settings shown in FIG. 9H may or may not be applied to matrix switch device 930 at the same time. For instance, a first switch setting may be first applied by the control circuitry and thus channels C0-C7 receives the electrical outputs 00-07 in the first switch setting. While the channels C0-C7 are processing the received electrical outputs, delivering them to the sampler, and / or simply waiting for the sampler to complete the analog-to- digital conversion, the control circuitry can apply the second switch setting to matrix switch device 930. In the second switch setting, some of the electrical outputs 00-07 are combined and directed to different channels (e.g., C8, CIO, and Cl 3). As a result, the C0-C7 channels are not affected, and different switched outputs from switch device 930 in different switch settings can be processed in parallel using different groups of channels. In the above example, channels C0- C7 may form one group and channels C8, CIO, and C13 may form another group. Parallel processing of the electrical outputs using different switch settings can improve the processing throughput and enhance the overall performance and bandwidth of the light receiver. The higher performance and / or the higher bandwidth of the light receiver may be desired at some mission- critical applications like autonomous driving.

[0130] The above examples of different scenarios of controlling the switch settings of the matrix switch device 930 for sequential processing or parallel processing are for illustrative purposes. It is understood that different kinds of switch settings and configurations can be implemented using a matrix switch device (e.g., device 930) to achieve the desired light receiver performance.

[0131] FIGs. 11A-1 IB are block diagrams illustrating an example sampler 1150 in accordance with various embodiments. As shown in FIG. 11A, sampler 1150 receives the switched outputs from a matrix switch device (e.g., device 930) via channels 1140A-N (collectively as channels 1140). Channels 1140 may include electrical wires or other transmission lines for conducting analog electrical signals (e.g., current signals or voltage signals). In some examples, channels 1140 may also include pre-amplifiers, filters, couplers, repeaters, or other signal processing components. The analog electrical signals (or pre-processed signals) are provided to analog-to- digital converters (ADCs) 1152A-N (collectively as 1152) for processing. ADCs convert analog signals to digital signals, which are provided as digital outputs 1160A-N (collectively as 1160). The digital outputs 1160 can then be used for downstream processing such as creating a point cloud. FIG. 11 A shows that each of channels 1140A-1 MON may be connected to a corresponding ADC 1152A-1152N in sampler 1150. And if each channel 1140 receives anelectrical output from a different light detector, each ADC in sampler 1 1 0 then corresponds to a different light detector. This configuration may be used with the switch setting shown in FIG.9A (e.g., each light detector 910 provides an electrical output 912 to a corresponding channel 940 to form a switched output, which is in turn provided to a corresponding ADC 1152). In FIG. 11A, if a channel (e.g., channel 1140A) receives a switched output that combines two or more electrical outputs (e.g., 00+01), the ADC (e.g., 1152A) can receive and convert the combined electrical output to a digital output (e.g., output 1160A). This configuration may be used with the switch settings shown in FIGs. 9B-9D.

[0132] FIG. 1 IB illustrates another example of the sampler 1152, uses time-to-digital converters (TDCs) 1 154. A TDC is a device for recognizing events and providing a digital representation of the time they occurred. For example, the TDC may output the time of arrival of each incoming analog signal or pulse. TDCs can be used to measure time intervals between two signals or pulses, which may be useful in the measurement of the time-of-flight for a LiDAR system. In one example shown in FIG. 1 IB, TDCs 1154A-1154N are connected to channels 1140A-1 MOL, respectively, and convert received signals to digital outputs 1160A-1160L, respectively. TDCs 1156A-1156N may be unused or disconnected if the corresponding channels 1140M-1 MON are also unused or disconnected. This configuration may correspond to the switch setting shown in FIGs. 9B-9E, where not all the channels are used. In the configuration shown in FIG. 1 IB, channels 1140A-1 MOL may be used to receive switched outputs when the matrix switch device is in the first switch setting; and channels 1140M-1 MON may be used to, for example, receive switched outputs when the matrix switch device is in a second switch setting. Therefore, the TDCs 1154A-N and 1156A-N can be used for parallel processing of the received switched outputs in multiple switch settings, thereby improving the throughput and performance of the light receiver. The samplers 1150 and 1152 are not limited to the above examples, and can use, for example, a mix of ADCs and TDCs. Samplers 1150 and 1152 may also be referred to as digital samplers because they provide digital outputs.

[0133] FIG. 12A is a flowchart illustrating a method for performing light detection by a light receiver. The light receiver may be light receiver 700 described above. The light receiver may be a part of a LiDAR system (e.g., system 300) as described above. As shown in FIG. 12A, in block 1202, a plurality of light detectors (e.g., detectors 910) in the light receiver light receives light from a field-of-view (FOV) of a LiDAR system. In some embodiments, the received lightcomprises scattered or reflected light based on transmission light of the LiDAR system illuminating one or more objects in the FOV. The plurality of light detectors comprises a V-by- array of light detectors arranged on a surface of the light receiver, wherein the N and the M are integer numbers.

[0134] In block 1204, the light detectors generate a plurality of electrical outputs (e.g., outputs 912) based on the received light. In block 1206, control circuitry (e.g., circuitry 350) controls a matrix switch device (e.g., device 930) to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors. Controlling the matrix switch device comprises configuring the matrix switch device to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system. In some embodiments, the light receiver further comprises a plurality of channels coupled between the matrix switch device and a sampler, wherein the matrix switch device comprises a plurality of electrical switches controlled based on the plurality of different switch settings.

[0135] In some embodiments, the detection results comprise one or more of: a detection distance, a detected object reflectivity, detected signal strength from one or more of the plurality of light detectors, a detected signal strength distribution, and a detected signal -to-noise (SNR) ratio. In some embodiments, the operational conditions of the LiDAR system comprise one or more of: a scanning angle of the LiDAR system, a scanning direction of the LiDAR system, a laser power setting, a region-of-interest (ROI) setting, and a detection sensitivity setting.

[0136] In block 1208, a sampler (e.g., sampler 1150 or 1152) generates, based on the switched outputs, at least one digital output (e.g., output 1160) representing the received light.

[0137] Various different switch settings are illustrated by FIG. 12B. With reference to FIG. 12B, the control circuitry can configure the matrix switch device to have a first switch setting 1212. The electrical switches in the first switch setting are controlled to direct each electrical output of the plurality of electrical outputs to a corresponding one of the plurality of channels. An example first switch setting is illustrated using FIG. 9A. To configure the first switch setting, the control circuitry may determine that the detection results may comprise a first detected distance of a first object located within a threshold distance from the LiDAR system; and / or that the operational conditions of the LiDAR system comprise a scanning angle of the LiDAR system being at or below the horizon. As such, the matrix switch device is controlled to have the firstswitch setting if the LiDAR system scans the first object located within the threshold distance from the LiDAR system and / or if the scanning angle of the LiDAR system is at or below the horizon.

[0138] In another example, the control circuitry can configure the matrix switch device to have a second switch setting 1214. In the second switch setting, the electrical switches combine two or more electrical outputs from the plurality of light detectors to form a combined electrical output; and the combined electrical output is directed to a designated channel of the plurality of channels. Example second switch settings are illustrated using FIGs. 9B-9D. To configure the second switch setting, the control circuitry may determine that the detection results comprise a second detected distance of a second object located outside of a threshold distance from the LiDAR system; and / or that the operational conditions of the LiDAR system comprise a scanning angle of the LiDAR system being above the horizon. As such, the matrix switch device is controlled to have the second switch setting if the LiDAR system scans the second object located outside of the threshold distance from the LiDAR system and / or if the scanning angle of the LiDAR system is above the horizon.

[0139] In some embodiments, the control circuitry can configure the matrix switch device to have a third switch setting 1220. In the third switching setting, the matrix switch device is configured such that not all electrical outputs from the plurality of light detectors are used in forming the switched outputs. An example third switch setting is illustrated using FIG. 9E.

[0140] In some embodiments, the control circuitry can configure the matrix switch device to have multiple switch settings 1216, such that the control circuitry controls multiple electronic switches of the matrix switch device to sequentially direct the plurality of electrical outputs of the light detectors to the plurality of channels (e.g., channel 940). Example multiple switching settings 1216 for sequential processing are illustrated using FIGs. 9F-9G.

[0141] In some embodiments, the control circuitry can configure the matrix switch device to have multiple switch settings 1218, such that the control circuitry controls multiple electronic switches of the matrix switch device to direct, in parallel, the plurality of electrical outputs of the light detectors to the plurality of channels (e.g., channel 940). Example multiple switching settings 1218 for parallel processing are illustrated using FIG. 9H.

[0142] The foregoing specification is to be understood as being in every respect illustrative and exemplary, but not restrictive, and the scope of the invention disclosed herein is not to be determined from the specification, but rather from the claims as interpreted according to the full breadth permitted by the patent laws. It is to be understood that the embodiments shown and described herein are only illustrative of the principles of the present invention and that various modifications may be implemented by those skilled in the art without departing from the scope and spirit of the invention. Those skilled in the art could implement various other feature combinations without departing from the scope and spirit of the invention.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A light receiver of a light detection and ranging (LiDAR) system, comprising: a plurality of light detectors configured to receive light from a field-of-view (FOV) of the LiDAR system and generate a plurality of electrical outputs based on the received light; a matrix switch device controlled to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors, wherein the matrix switch device is configurable to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system; and a sampler configured to generate, based on the switched outputs, at least one digital output representing the received light,2. The light receiver of claim 1, wherein the received light comprises scattered or reflected light based on transmission light of the LiDAR system illuminating one or more objects in the FOV.

3. The light receiver of any of claims 1-2, wherein the plurality of light detectors comprises a V-by-'V / array of light detectors arranged on a surface of the light receiver, wherein the N and the M are integer numbers.

4. The light receiver of any of claims 1-3, wherein the detection results comprise one or more of: a detection distance, a detected object reflectivity, detected signal strength from one or more of the plurality of light detectors, a detected signal strength distribution, a detected signal - to-noise (SNR) ratio, and feedback from a perception system.

5. The light receiver of any of claims 1-4, wherein the operational conditions of the LiDAR system comprise one or more of:a scanning angle of the LiDAR system, a scanning direction of the LiDAR system, a laser power setting, a region-of-interest (ROI) setting, a detection sensitivity setting, a receiving buffer duration, and a receiving timing resolution.

6. The light receiver of any of claims 1-5, further comprising a plurality of channels coupled between the matrix switch device and the sampler, wherein the matrix switch device comprises a plurality of electrical switches controlled based on the plurality of different switch settings.

7. The light receiver of claim 6, wherein: the plurality of different switch settings comprises a first switch setting; and the electrical switches in the first switch setting are controlled to direct each electrical output of the plurality of electrical outputs to a corresponding one of the plurality of channels.

8. The light receiver of claim 7, wherein: the detection results comprise a first detected distance of a first object located within a threshold distance from the LiDAR system; the operational conditions of the LiDAR system comprise a scanning angle of the LiDAR system being at or below the horizon; and the matrix switch device is controlled to have the first switch setting if the LiDAR system scans the first object located within the threshold distance from the LiDAR system and / or if the scanning angle of the LiDAR system is at or below the horizon.

9. The light receiver of claim 6, wherein: the plurality of different switch settings comprises a second switch setting; the electrical switches in the second switch setting combine two or more electrical outputs from the plurality of light detectors to form a combined electrical output; and the combined electrical output is directed to a designated channel of the plurality of channels.

10. The light receiver of claim 9, wherein:the detection results comprise a second detected distance of a second object located outside of a threshold distance from the LiDAR system; the operational conditions of the LiDAR system comprise a scanning angle of the LiDAR system being above the horizon; and the matrix switch device is controlled to have the second switch setting if the LiDAR system scans the second object located outside of the threshold distance from the LiDAR system and / or if the scanning angle of the LiDAR system is above the horizon.

11. The light receiver of any of claims 6-10, wherein the plurality of electrical switches are semiconductor transistors based switches.

12. The light receiver of any of claims 6-11, wherein a number of the plurality of channels is fewer than or equal to a number of the light detectors.

13. The light receiver of any of claims 6-12, wherein the plurality of channels are configured to sequentially receive the switched outputs formed in multiple switch settings of the plurality of different switch settings.

14. The light receiver of any of claims 6-11, wherein a number of the plurality of channels is greater than a number of the light detectors.

15. The light receiver of any of claims 6-11 and 14, wherein the plurality of channels are configured to receive, in parallel, the switched outputs formed in multiple switch settings of the plurality of different switch settings.

16. The light receiver of any of claims 1-15, wherein the matrix switch device is configured to have a particular switch setting of the plurality of different switch settings such that not all electrical outputs from the plurality of light detectors are used in forming the switched outputs.

17. The light receiver of any of claims 1-16, wherein the detection results or the operational conditions of the LiDAR system are with respect to a past time point, a current time point, or a future time point.

18. The light receiver of any of claims 1 -17, wherein the sampler comprises at least one of: a plurality of analog-to-digital converters (ADCs); or a plurality of time-to-digital converters (TDCs).

19. A light ranging and detection (LiDAR) system, comprising: a light source configured to transmit laser light; a scanner configured to scan the laser light to a field-of-view; a controller; and a light receiver of any of claims 1-18.

20. A vehicle comprising the system of claim 19.

21. A method for performing light detection by a light receiver, comprising: receiving, by a plurality of light detectors, light from a field-of-view (FOV) of a LiDAR system; generating a plurality of electrical outputs based on the received light; controlling, by control circuitry, a matrix switch device to form switched outputs based on the plurality of electrical outputs from the plurality of light detectors, wherein controlling the matrix switch device comprises: configuring the matrix switch device to have a plurality of different switch settings based on at least one of detection results or operational conditions of the LiDAR system; and generating, by a sampler and based on the switched outputs, at least one digital output representing the received light.

22. The method of claim 21, wherein the received light comprises scattered or reflected light based on transmission light of the LiDAR system illuminating one or more objects in the FOV.

23. The method of any of claims 21-22, wherein the plurality of light detectors comprises a JV-by- array of light detectors arranged on a surface of the light receiver, wherein the N and the AL are integer numbers.

24. The method of any of claims 21-23, wherein the detection results comprise one or more of: a detection distance, a detected object reflectivity, detected signal strength from one or more of the plurality of light detectors, a detected signal strength distribution, a detected signal - to-noise (SNR) ratio, and feedback from a perception system.

25. The method of any of claims 21-24, wherein the operational conditions of the LiDAR system comprise one or more of: a scanning angle of the LiDAR system, a scanning direction of the LiDAR system, a laser power setting, a region-of-interest (ROI) setting, a detection sensitivity setting, a receiving buffer duration, and a receiving timing resolution.

26. The method of any of claims 21-25, further comprising: receiving the switched outputs by a plurality of channels coupled between the matrix switch device and the sampler, wherein the matrix switch device comprises a plurality of electrical switches controlled based on the plurality of different switch settings.

27. The method of claim 26, wherein: the plurality of different switch settings comprises a first switch setting; and the electrical switches in the first switch setting are controlled to direct each electrical output of the plurality of electrical outputs to a corresponding one of the plurality of channels.

28. The method of claim 27, wherein: the detection results comprise a first detected distance of a first object located within a threshold distance from the LiDAR system; the operational conditions of the LiDAR system comprise a scanning angle of the LiDAR system being at or below the horizon; andthe matrix switch device is controlled to have the first switch setting if the LiDAR system scans the first object located within the threshold distance from the LiDAR system and / or if the scanning angle of the LiDAR system is at or below the horizon.

29. The method of claim 26, wherein: the plurality of different switch settings comprises a second switch setting; the electrical switches in the second switch setting combine two or more electrical outputs from the plurality of light detectors to form a combined electrical output; and the combined electrical output is directed to a designated channel of the plurality of channels.

30. The method of claim 29, wherein: the detection results comprise a second detected distance of a second object located outside of a threshold distance from the LiDAR system; the operational conditions of the LiDAR system comprise a scanning angle of the LiDAR system being above the horizon; and the matrix switch device is controlled to have the second switch setting if the LiDAR system scans the second object located outside of the threshold distance from the LiDAR system and / or if the scanning angle of the LiDAR system is above the horizon.

31. The method of any of claims 26-30, wherein the plurality of electrical switches are semiconductor transistors based switches.

32. The method of any of claims 26-31, wherein a number of the plurality of channels is fewer than or equal to a number of the light detectors.

33. The method of any of claims 26-32, wherein the plurality of channels are configured to sequentially receive the switched outputs formed in multiple switch settings of the plurality of different switch settings.

34. The method of any of claims 26-31, wherein a number of the plurality of channels is greater than a number of the light detectors.

35. The method of any of claims 26-31 and 34, wherein receiving the switched outputs comprises: receiving, by the plurality of channels, in parallel, the switched outputs formed in multiple switch settings of the plurality of different switch settings.

36. The method of any of claims 21-35, wherein the matrix switch device is configured to have a particular switch setting of the plurality of different switch settings such that not all electrical outputs from the plurality of light detectors are used in forming the switched outputs.

37. The method of any of claims 21-36, wherein the detection results or the operational conditions of the LiDAR system are with respect to a past time point, a current time point, or a future time point.

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