Detector alignment method for laser radar production

Abstract

The invention provides an apparatus for transceiver alignment in a LiDAR system. The apparatus includes a detector package and a plurality of detector elements mounted to the detector package. The apparatus further includes one or more light-forming indicia mounted to the detector package at predetermined positions relative to the plurality of detector elements. The predetermined position of the one or more light-forming marks is configured to facilitate alignment of each detector element of the plurality of detector elements with a corresponding emitter channel of the plurality of emitter channels.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority of U.S. Patent Application No. 18 / 542,014, entitled "DETECTOR ALIGNMENT METHOD FOR LIDAR PRODUCTION", filed on Dec. 15, 2023, which claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 434,459, entitled "DETECTOR ALIGNMENT METHOD FOR LIDAR PRODUCTION", filed on Dec. 21, 2022. For all purposes, the contents of these applications are hereby incorporated by reference in their entirety. Technical Field

[0003] The present disclosure generally relates to detector devices and, more particularly, to devices for transceiver alignment in optical ranging and detection (LiDAR) systems. Background Art

[0004] Optical detection and ranging (LiDAR) systems use light pulses to create an image or point cloud of the external environment. LiDAR systems can be scanning or non - scanning systems. Some typical scanning LiDAR systems include a light source, a light emitter, an optical steering system, and a light detector. The light source generates a light beam that, when emitted from the LiDAR system, is directed by the optical steering system in a specific direction. When the emitted 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 when the return light pulse is detected and the time when the corresponding light pulse in the light beam is emitted, the LiDAR system can determine the distance to the object based on the speed of light. This technique for determining distance is known as time - of - flight (ToF) technique. The optical steering system can direct the light beam along different paths to allow the LiDAR system to scan the surrounding environment and generate an image or point cloud. A typical non - scanning LiDAR system irradiates the entire field of view (FOV) instead of scanning the entire FOV. An example of a non - scanning LiDAR system is flash LiDAR, which can also use the ToF technique 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 of the Invention

[0005] The embodiments provided in the present disclosure are devices and methods for transceiver alignment in a LiDAR system. In one embodiment, a device for transceiver alignment in a LiDAR system is provided. The device is suitable for mass production. The device includes a detector package and a plurality of detector elements mounted to the detector package. The device further includes one or more light-forming marks mounted to the detector package at predetermined positions relative to the plurality of detector elements. The predetermined positions of the one or more light-forming marks are configured to facilitate alignment of each of the plurality of detector elements with a corresponding emitter channel among a plurality of emitter channels.

[0006] In one embodiment, a method for transceiver alignment in a LiDAR system is provided. The method includes controlling a plurality of emitter channels to emit a plurality of transmitted light beams towards an imaging device, and causing one or more light-forming marks to emit light towards the imaging device. The one or more light-forming marks are positioned at predetermined positions relative to the plurality of detector elements based on alignment requirements of the plurality of detector elements. The method further includes forming an image of the plurality of transmitted light beams and an image of the one or more light-forming marks, and aligning the plurality of emitter channels relative to the plurality of detector elements based on the image of the transmitted light beams and the image of the one or more light-forming marks.

[0007] In one embodiment, a LiDAR system including a device for transceiver alignment in a LiDAR system is provided. The device includes a detector package and a plurality of detector elements mounted to the detector package. The device further includes one or more light-forming marks mounted to the detector package at predetermined positions relative to the plurality of detector elements. The predetermined positions of the one or more light-forming marks are configured to facilitate alignment of each of the plurality of detector elements with a corresponding emitter channel among a plurality of emitter channels.

[0008] In one embodiment, a LiDAR system including a device that executes a method for transceiver alignment in a LiDAR system is provided. The method includes controlling a plurality of emitter channels to emit a plurality of transmitted light beams towards an imaging device, and causing one or more light-forming marks to emit light towards the imaging device. The one or more light-forming marks are positioned at predetermined positions relative to the plurality of detector elements based on alignment requirements of the plurality of detector elements. The method further includes forming an image of the plurality of transmitted light beams and an image of the one or more light-forming marks, and aligning the plurality of emitter channels relative to the plurality of detector elements based on the image of the transmitted light beams and the image of the one or more light-forming marks.

[0009] In one embodiment, a vehicle including a LiDAR system is provided. The LiDAR system includes a device for transceiver alignment in the LiDAR system. The device includes a detector package and a plurality of detector elements mounted to the detector package. The device further includes one or more light-forming markers mounted to the detector package at predetermined positions relative to the plurality of detector elements. The predetermined positions of the one or more light-forming markers are configured to facilitate alignment of each of the plurality of detector elements with a corresponding transmitter channel of a plurality of transmitter channels.

[0010] In one embodiment, a vehicle including a LiDAR system is provided. The LiDAR system includes a device that performs a method for transceiver alignment in the LiDAR system. The method includes controlling a plurality of transmitter channels to emit a plurality of transmitted light beams toward an imaging device and causing one or more light-forming markers to emit light toward the imaging device. The one or more light-forming markers are positioned at predetermined positions relative to the plurality of detector elements based on alignment requirements of the plurality of detector elements. The method further includes forming an image of the plurality of transmitted light beams and an image of the one or more light-forming markers, and aligning the plurality of transmitter channels relative to the plurality of detector elements based on the image of the transmitted light beams and the image of the one or more light-forming markers. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present application may be best understood by reference to the following embodiments, taken in conjunction with the accompanying drawings, in which like parts may be designated by like reference numerals.

[0012] Figure 1 Illustrates one or more exemplary LiDAR systems disposed in or included in a motor vehicle.

[0013] Figure 2 Is a block diagram illustrating the interaction between an exemplary LiDAR system and a plurality of other systems including a vehicle perception and planning system.

[0014] Figure 3 Is a block diagram illustrating an exemplary LiDAR system.

[0015] Figure 4 Is a block diagram illustrating an exemplary fiber-based laser source.

[0016] Figures 5A to 5C Illustrates an exemplary LiDAR system that uses a pulsed signal to measure the distance to an object disposed in a field of view (FOV).

[0017] Figure 6 Is a block diagram illustrating an exemplary apparatus for implementing systems, devices, and methods in various embodiments.

[0018] Figure 7A and Figure 7B is a diagram illustrating an example of an apparatus for transceiver alignment in a LiDAR system according to some embodiments.

[0019] Figures 8A to 8C is a diagram illustrating an example of transceiver alignment using light to form a mark according to some embodiments.

[0020] Figures 9A to 9G is a diagram illustrating an example of a light - formed mark according to some embodiments.

[0021] Figures 10A to 10I is a diagram illustrating an example of the position of a light - formed mark relative to detector elements according to some embodiments.

[0022] Figure 11 Illustrates an illustrative method for transceiver alignment in a LiDAR system according to some embodiments.

[0023] Figure 12 Illustrates an illustrative method for causing a light - formed mark to emit light according to some embodiments.

[0024] Figure 13 Illustrates an illustrative method for aligning multiple emitter channels according to some embodiments. Detailed Description

[0025] To more thoroughly understand the various embodiments of the present invention, the following description sets forth numerous specific details, such as specific configurations, parameters, examples, etc. However, it should be recognized that this description is not intended to limit the scope of the present invention, but rather to provide a better description of the exemplary embodiments.

[0026] Throughout the specification and claims, unless the context clearly dictates otherwise, the following terms have the meanings explicitly associated herein:

[0027] As used herein, the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may be. Thus, as described below, the various embodiments of the present invention can be readily combined without departing from the scope or spirit of the present disclosure.

[0028] As used herein, the term "or" is the inclusive "or" operator and is equivalent to the term "and / or" unless the context clearly dictates otherwise.

[0029] The term "based on" is not exclusive and allows for additional factors not described, unless the context clearly dictates otherwise.

[0030] As used herein, unless the context requires otherwise, the term "coupled to" is intended to include both direct coupling (where two elements that are coupled together touch each other) and indirect coupling (where at least one additional element is located between the two elements). Thus, the terms "coupled to" and "coupled with" are used synonymously. In the context of a networking environment in which 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" via one or more intermediate devices. A component or device can be optical, mechanical, and / or electrical.

[0031] Although the following description uses the terms "first", "second", etc. to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the various described examples, a first sensor can be referred to as a second sensor, and similarly, a second sensor can be referred to as a first sensor. Both the first sensor and the second sensor can be sensors, and in some cases, can be separate and distinct sensors.

[0032] In addition, throughout the specification, the meanings of "a", "an", and "the" include the plural, and the meaning of "in" can include "in" and "on".

[0033] Although some of the various embodiments presented herein constitute a single combination of inventive elements, it should be understood that the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment includes elements A, B, and C, and another embodiment includes elements B and D, the inventive subject matter is also considered to include the other remaining combinations of A, B, C, or D, even if not explicitly discussed herein. Additionally, the transitional term "comprising" means having the components or elements, or being those components or elements. As used herein, the transitional term "comprising" is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

[0034] As used in the description herein and throughout the following claims, when a system, engine, server, device, module, or other computing element is described as being configured to perform or execute a function 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 perform the set of functions on target data or data objects stored in the memory.

[0035] It should be noted that any language for a computer should be understood 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 jointly). It should be understood that a computing device includes a processor configured to execute software instructions stored on a tangible non-transitory computer-readable storage medium (e.g., hard disk drive, FPGA, PLA, solid-state drive, RAM, flash memory, ROM, or any other volatile or non-volatile storage device). The software instructions configure or program the computing device to provide roles, responsibilities, or other functions as discussed below with respect to the disclosed apparatus. Additionally, the disclosed technology may be embodied as a computer program product that includes a non-transitory computer-readable medium storing software instructions that cause a processor to perform the disclosed steps associated with the implementation of computer-based algorithms, processes, methods, or other instructions. In some embodiments, various servers, systems, databases, or interfaces exchange data using standardized protocols or algorithms, possibly based on HTTP, HTTPS, AES, public-private key exchange, web service APIs, known financial transaction protocols, or other methods of electronic information exchange. Data exchange between devices can be through: packet-switched networks, the Internet, LANs, WANs, VPNs, or other types of packet-switched networks; circuit-switched networks; cell-switched networks; or other types of networks.

[0036] A LiDAR system includes a plurality of transmitter channels configured to emit a plurality of transmitted beams. When the transmitted beams propagate to illuminate one or more objects in the FOV, at least a portion of the transmitted beams is reflected or scattered to form return light. The LiDAR system further includes a plurality of detector elements on the receiver side, the plurality of detector elements being configured to detect the return light. In one example, the plurality of detector elements can be an avalanche photodiode (APD) array. The plurality of transmitter channels and the plurality of detector elements are part of a transceiver and are sometimes collectively referred to as the transceiver. It is desirable to have transceiver alignment in the LiDAR system such that the plurality of detector elements can collect as much of the return light formed based on the transmitted beams as possible, thereby achieving high sensitivity of the LiDAR system.

[0037] LiDAR systems are sensitive to light collection efficiency. The alignment of multiple detector elements may have a side effect on the performance of LiDAR. One method for aligning multiple detector elements is to use a target with a known reflectivity at a long distance (e.g., >200 m) to optimize the return light returning from the target. However, this may not be feasible for production. Another method for transceiver alignment includes two steps. The first step is to measure the characteristics of the transmitted beam, such as beam angle, beam height, beam divergence, etc. The second step is to apply a device to simulate or replace the return light from an illuminated target at a long distance (e.g., >200 m). However, this method is time-consuming and limits the production capacity. Therefore, there is a need for an alignment method suitable for mass production and improving the production capacity.

[0038] Embodiments of the present invention are described below. In various embodiments of the present invention, an alignment method suitable for mass production is provided. The method also provides measurable optimization metrics to ensure good alignment results. The method includes controlling multiple emitter channels to emit multiple transmitted beams towards an imaging device, and causing one or more light-forming markers to emit light towards the imaging device. One or more light-forming markers are positioned at predetermined positions relative to the multiple detector elements based on the alignment requirements of the multiple detector elements. The method further includes forming images of the multiple transmitted beams and images of the one or more light-forming markers, and aligning the multiple emitter channels relative to the multiple detector elements based on the images of the transmitted beams and the images of the one or more light-forming markers.

[0039] Figure 1Illustrated are one or more exemplary LiDAR systems 110 and 120A - 120I disposed or included in a motor vehicle 100. The vehicle 100 can be an automobile, a sport utility vehicle (SUV), a truck, a train, a van, a bicycle, a motorcycle, a tricycle, a bus, a motor scooter, a streetcar, a ship, a boat, an underwater vehicle, an airplane, a helicopter, an unmanned aerial vehicle (UAV), a spacecraft, etc. The motor vehicle 100 can be a vehicle with any level of automation. For example, the 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 human driver intervention. For example, a partially automated vehicle can perform blind spot monitoring, lane keeping and / or lane change operations, automatic emergency braking, intelligent cruise, and / or traffic following, etc. Certain operations of a partially automated vehicle may be limited to specific applications or driving scenarios (e.g., limited to highway driving). A highly automated vehicle can generally perform all operations of a partially automated vehicle with fewer limitations. A highly automated vehicle can also detect its own limits when operating the vehicle and, when necessary, request the driver to take over control of the vehicle. A fully automated vehicle can perform all vehicle operations without driver intervention but can also detect its own limits and, when necessary, request the driver to take over. A driverless vehicle can operate on its own without any driver intervention.

[0040] In a typical configuration, the motor vehicle 100 includes one or more LiDAR systems 110 and 120A - 120I. Each of the LiDAR systems 110 and 120A - 120I can be a scanning - based LiDAR system and / or a non - scanning LiDAR system (e.g., 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 the field of view (FOV). A non - scanning LiDAR system emits laser light without scanning to illuminate the FOV. For example, flash LiDAR is a type of non - scanning LiDAR system. Flash LiDAR can emit laser light and use a single light pulse or burst to simultaneously illuminate the FOV.

[0041] LiDAR systems are common sensors for at least partially automated vehicles. In one embodiment, as Figure 1As shown, the 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., on top of the vehicle). Disposing the LiDAR system 110 on top of the vehicle facilitates 360 - degree scanning around the vehicle 100. In some other embodiments, the motor vehicle 100 may include multiple LiDAR systems, including two or more of systems 110 and / or 120A - 120I. As Figure 1 shown, in one embodiment, multiple LiDAR systems 110 and / or 120A - 120I are attached to the vehicle 100 at different positions of the vehicle. For example, LiDAR system 120A is attached to the vehicle 100 at the right front corner; LiDAR system 120B is attached to the vehicle 100 at the front center position; LiDAR system 120C is attached to the vehicle 100 at the left front corner; LiDAR system 120D is attached to the vehicle 100 at the right side rearview mirror; LiDAR system 120E is attached to the vehicle 100 at the left side rearview mirror; LiDAR system 120F is attached to the vehicle 100 at the rear center position; LiDAR system 120G is attached to the vehicle 100 at the right rear corner; LiDAR system 120H is attached to the vehicle 100 at the left rear corner; and / or LiDAR system 120I is attached to the vehicle 100 at the center facing the rear end (e.g., the rear end of the top of the vehicle). It should be understood that one or more LiDAR systems may be distributed and attached to the vehicle in any desired manner, and Figure 1 only one embodiment is illustrated. As another example, LiDAR systems 120D and 120E may be attached to the B - pillar of the vehicle 100 instead of the rearview mirrors. As another example, LiDAR system 120B may be attached to the windshield of the vehicle 100 instead of the front bumper.

[0042] In some embodiments, LiDAR systems 110 and 120A - 120I are independent LiDAR systems, having their respective laser sources, control electronics, transmitters, receivers, and / or steering mechanisms. In other embodiments, some of the LiDAR systems 110 and 120A - 120I may share one or more components, thus 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 example, system 110 (or another system located at the center or any location of vehicle 100) includes a light source, a transmitter, and a photodetector, but no steering mechanism. System 110 can distribute the transmitted light to each of systems 120A - 120I. The transmitted light can be distributed via optical fibers. Optical connectors can be used to couple the optical fibers to each of systems 110 and 120A - 120I. In some examples, one or more of the systems 120A - 120I include a steering mechanism, but no light source, transmitter, or photodetector. The steering mechanism can include one or more movable mirrors, such as one or more polygon mirrors, one or more single - plane mirrors, one or more multi - plane mirrors, etc. Embodiments of the light source, transmitter, steering mechanism, and photodetector will be described in more detail below. Via the steering mechanism, one or more of the systems 120A - 120I scan light into one or more corresponding FOVs and receive the corresponding returned light. The returned light is formed by scattering or reflecting the transmitted light by one or more objects in the FOV. Systems 120A - 120I may also include collection lenses and / or other optics to focus and / or direct the returned light into an optical fiber, which delivers the received returned light to system 110. System 110 includes one or more photodetectors for detecting the received returned light. In some examples, system 110 is disposed inside the vehicle such that it is in a temperature - controlled environment, while one or more of the systems 120A - 120I may be at least partially exposed to the external environment.

[0043] Figure 2 FIG. 200 is a block diagram illustrating the interaction between an in - vehicle LiDAR system 210 and a plurality of other systems including a vehicle perception and planning system 220. The LiDAR system 210 can be mounted on or integrated into a vehicle. The LiDAR system 210 includes sensors that scan laser light into the surrounding environment to measure the distance, angle, and / or velocity of objects. Based on the scattered light returned to the LiDAR system 210, it can generate sensor data (e.g., image data or 3D point cloud data) representing the perceived external environment.

[0044] The LiDAR system 210 may include one or more of a short-range LiDAR sensor, a mid-range LiDAR sensor, and a long-range LiDAR sensor. The short-range LiDAR sensor measures objects up to approximately 20 - 50 meters away from the LiDAR sensor. The short-range LiDAR sensor can be used, for example, to monitor nearby moving objects (e.g., pedestrians crossing the road in a school zone), parking assistance applications, etc. The mid-range LiDAR sensor measures objects up to approximately 70 - 200 meters away from the LiDAR sensor. The mid-range LiDAR sensor can be used, for example, to monitor road intersections, assist in merging onto or leaving a highway, and so on. The long-range LiDAR sensor measures objects located 200 meters and above. The long-range LiDAR sensor is typically used when the vehicle is traveling at high speed (e.g., on a highway), such that the vehicle's control system may have only a few seconds (e.g., 6 - 8 seconds) to respond to any situation detected by the LiDAR sensor. As Figure 2 shown, in one embodiment, the LiDAR sensor data can be provided to the vehicle perception and planning system 220 via the communication path 213 for further processing and control of vehicle operation. The communication path 213 can be any wired or wireless communication link capable of transmitting data.

[0045] Still referring to Figure 2 , in some embodiments, other vehicle sensors 230 are configured to provide additional sensor data either individually or in conjunction with the LiDAR system 210. The other vehicle sensors 230 can include, for example, one or more cameras 232, one or more radars 234, one or more ultrasonic sensors 236, and / or other sensors 238. The camera 232 can capture images and / or videos of the vehicle's external environment. The camera 232 can capture, for example, high-definition (HD) video with millions of pixels per frame. The camera includes an image sensor that facilitates the generation of monochromatic or color images and videos. Color information may be important in interpreting data in certain situations (e.g., interpreting an image of a traffic light). Color information may not be obtainable from other sensors such as LiDAR or radar sensors. The camera 232 can include one or more of a narrow-focus camera, a wide-focus camera, a side camera, an infrared camera, a fisheye camera, etc. The image and / or video data generated by the camera 232 can also be provided to the vehicle perception and planning system 220 via the communication path 233 for further processing and control of vehicle operation. The communication path 233 can be any wired or wireless communication link capable of transmitting data. The camera 232 can be mounted or integrated onto the vehicle at any location (e.g., rearview mirror, pillar, front grille, and / or rear bumper, etc.).

[0046] Other vehicle-mounted sensors 230 may also include a radar sensor 234. The radar sensor 234 uses radio waves to determine the distance, angle, and speed of an object. The radar sensor 234 generates electromagnetic waves in the radio or microwave spectrum. The electromagnetic waves are reflected by the object, and some of the reflected waves return to the radar sensor, providing information about the object's position and speed. The radar sensor 234 may include one or more of short-range radar, mid-range radar, and long-range radar. The short-range radar measures objects at a distance of about 0.1 - 30 meters from the radar. The short-range radar is useful for detecting objects near a vehicle (such as other vehicles, buildings, walls, pedestrians, cyclists, etc.). The short-range radar can be used for detecting blind spots, assisting with lane changes, providing rear-end collision warnings, assisting with parking, providing emergency braking, etc. The mid-range radar measures objects at a distance of about 30 - 80 meters from the radar. The long-range radar measures objects located at about 80 - 200 meters. The mid-range and / or long-range radar can be used for, for example, traffic tracking, adaptive cruise control, and / or highway automatic braking. The sensor data generated by the radar sensor 234 can also be provided to the vehicle perception and planning system 220 via the communication path 233 for further processing and control of vehicle operations. The radar sensor 234 can be mounted or integrated into the vehicle at any location (such as the rearview mirror, pillar, front grille, and / or rear bumper, etc.).

[0047] Other vehicle-mounted sensors 230 may also include an ultrasonic sensor 236. The ultrasonic sensor 236 uses sound waves or pulses to measure an object located outside the vehicle. The sound waves generated by the ultrasonic sensor 236 are emitted into the surrounding environment. At least some of the emitted waves are reflected by the object and return to the ultrasonic sensor 236. Based on the returned signal, the distance to the object can be calculated. The ultrasonic sensor 236 can be used for, for example, checking blind spots, identifying parking spaces, providing lane change assistance in traffic, etc. The sensor data generated by the ultrasonic sensor 236 can also be provided to the vehicle perception and planning system 220 via the communication path 233 for further processing and control of vehicle operations. The ultrasonic sensor 236 can be mounted or integrated into the vehicle at any location (such as the rearview mirror, pillar, front grille, and / or rear bumper, etc.).

[0048] In some embodiments, one or more other sensors 238 may be attached in the vehicle and may also generate sensor data. The other sensors 238 may include, for example, a global positioning system (GPS), an inertial measurement unit (IMU), etc. The sensor data generated by the other sensors 238 can also be provided to the vehicle perception and planning system 220 via the communication path 233 for further processing and control of vehicle operations. It should be understood that the communication path 233 may include one or more communication links to transmit data between the various sensors 230 and the vehicle perception and planning system 220.

[0049] In some embodiments, as Figure 2 shown, sensor data from other vehicle sensors 230 can be provided to the vehicle LiDAR system 210 via a communication path 231. The LiDAR system 210 can process the sensor data from other vehicle sensors 230. For example, sensor data from a camera 232, a radar sensor 234, an ultrasonic sensor 236, and / or other sensors 238 can be correlated or fused with the sensor data of the LiDAR system 210, thereby at least partially offloading the sensor fusion process performed by the vehicle perception and planning system 220. It should be understood that other configurations can also be implemented to transmit and process sensor data from various sensors (e.g., the data can be transmitted to a cloud or an 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 the LiDAR system 210).

[0050] Still referring to Figure 2 , in some embodiments, sensors on other vehicles 250 are used to provide additional sensor data alone or in conjunction with the LiDAR system 210. For example, two or more nearby vehicles can have their respective LiDAR sensors, cameras, radar sensors, ultrasonic sensors, etc. The nearby vehicles can communicate with each other and share sensor data. Communication between vehicles is also referred to as V2V (vehicle-to-vehicle) communication. For example, as Figure 2 shown, the sensor data generated by other vehicles 250 can be transmitted to the vehicle perception and planning system 220 and / or the vehicle LiDAR system 210 via a communication path 253 and / or a communication path 251, respectively. The communication paths 253 and 251 can be any wired or wireless communication link capable of transmitting data.

[0051] Sharing sensor data facilitates better perception of the environment outside the vehicle. For example, a first vehicle may not sense a pedestrian behind a second vehicle but approaching the first vehicle. The second vehicle can share the sensor data related to the pedestrian with the first vehicle, so that the first vehicle can have additional reaction time to avoid colliding with the pedestrian. In some embodiments, similar to the data generated by the sensors 230, the data generated by the sensors on other vehicles 250 can be correlated or fused with the sensor data generated by the LiDAR system 210 (or other LiDAR systems located in other vehicles), thereby at least partially offloading the sensor fusion process performed by the vehicle perception and planning system 220.

[0052] In some embodiments, the intelligent infrastructure system 240 is used to provide sensor data alone or in conjunction with the LiDAR system 210. Certain infrastructure can be configured to communicate with vehicles to transfer information and vice versa. The communication between a vehicle and the infrastructure is generally referred to as V2I (vehicle-to-infrastructure) communication. For example, the intelligent infrastructure system 240 can include intelligent traffic lights that can convey their status to approaching vehicles in a message such as "turn yellow in 5 seconds". The intelligent infrastructure system 240 can also include its own LiDAR system installed near intersections so that it can transfer traffic monitoring information to vehicles. For example, a vehicle turning left at an intersection may not have sufficient sensing capabilities because some of its own sensors may be blocked by oncoming traffic. In such a case, the sensors of the intelligent infrastructure system 240 can provide useful data to the vehicle turning left. Such data can include, for example, traffic conditions, object information in the vehicle's turning direction, traffic light status, and predictions. These sensor data generated by the intelligent infrastructure system 240 can be provided to the vehicle perception and planning system 220 and / or the on-vehicle LiDAR system 210 via communication paths 243 and / or 241 respectively. The communication paths 243 and / or 241 can include any wired or wireless communication link capable of transmitting data. For example, the sensor data from the intelligent infrastructure system 240 can be transmitted to the LiDAR system 210 and correlated or fused with the sensor data generated by the LiDAR system 210, thereby at least partially offloading the sensor fusion process performed by the vehicle perception and planning system 220. The above V2V and V2I communications are examples of vehicle-to-X (V2X) communications, where "X" represents any other device, system, sensor, infrastructure, etc. that can share data with a vehicle.

[0053] Still referring to Figure 2, via various communication paths, the vehicle perception and planning system 220 receives sensor data from one or more of the LiDAR system 210, other on-vehicle sensors 230, other vehicles 250, and / or the intelligent infrastructure system 240. In some embodiments, different types of sensor data are correlated and / or fused by the sensor fusion subsystem 222. For example, the sensor fusion subsystem 222 may use multiple images or videos captured by multiple cameras disposed at different positions of the vehicle to generate a 360-degree model. The sensor fusion subsystem 222 obtains sensor data from different types of sensors and uses the combined data to more accurately perceive the environment. For example, the on-vehicle camera 232 may not be able to capture clear images because it faces the sun or a light source directly (e.g., the headlights of another vehicle at night). The LiDAR system 210 may not be affected much, and thus the sensor fusion subsystem 222 can combine the sensor data provided by the camera 232 and the LiDAR system 210 and use the sensor data provided by the LiDAR system 210 to compensate for the unclear images captured by the camera 232. As another example, in rainy or foggy weather, the radar sensor 234 may work better than the camera 232 or the LiDAR system 210. Accordingly, the sensor fusion subsystem 222 can use the sensor data provided by the radar sensor 234 to compensate for the sensor data provided by the camera 232 or the LiDAR system 210.

[0054] In other examples, the sensor data generated by the other on-vehicle sensors 230 may have a lower resolution (e.g., radar sensor data), and thus may need to be correlated and confirmed by the LiDAR system 210, which typically has a higher resolution. For example, the radar sensor 234 can detect a manhole cover (also known as an inspection hole cover) as an object that the vehicle is approaching. Due to the low-resolution characteristics of the radar sensor 234, the vehicle perception and planning system 220 may not be able to determine whether the object is an obstacle that the vehicle needs to avoid. Therefore, the high-resolution sensor data generated by the LiDAR system 210 can be used to correlate and confirm that the object is a manhole cover and will not cause damage to the vehicle.

[0055] The vehicle perception and planning system 220 further includes an object classifier 223. Using the raw sensor data and / or the associated / fused data provided by the sensor fusion subsystem 222, the object classifier 223 can use any computer vision technology to detect and classify objects and estimate the positions of the objects. In some embodiments, the object classifier 223 can use machine learning-based techniques to detect and classify objects. Examples of machine learning-based techniques include those utilizing, such as region-based convolutional neural network (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).

[0056] The vehicle perception and planning system 220 further includes a road detection subsystem 224. The road detection subsystem 224 locates the road and identifies objects and / or markings on the road. For example, based on the raw or fused sensor data provided by the radar sensor 234, the camera 232, and / or the LiDAR system 210, the road detection subsystem 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, the road detection subsystem 224 can identify objects on the road (e.g., obstacles or debris on the road) and / or markings (e.g., lane lines, turn signs, crosswalk signs, etc.).

[0057] The vehicle perception and planning system 220 further includes a positioning and vehicle pose subsystem 225. Based on the raw or fused sensor data, the positioning and vehicle pose subsystem 225 can determine the position and the pose of the vehicle. For example, using the sensor data from the LiDAR system 210, the camera 232, and / or the GPS data, the positioning and vehicle pose subsystem 225 can determine the exact position of the vehicle on the road and the six degrees of freedom of the vehicle (e.g., whether the vehicle is moving forward or backward, up or down, left or right). In some embodiments, a high-definition (HD) map is used for vehicle positioning. The HD map can provide a very detailed three-dimensional computer map for accurately positioning the vehicle. For example, using the HD map, the positioning and vehicle pose subsystem 225 can accurately determine the current position of the vehicle (e.g., which lane of the road the vehicle is currently in and how close it is to the roadside or sidewalk) and predict the future position of the vehicle.

[0058] The vehicle perception and planning system 220 further includes an obstacle predictor 226. The objects identified by the object classifier 223 can be stationary (e.g., light poles, road signs) or dynamic (e.g., moving pedestrians, bicycles, another vehicle). For moving objects, predicting their movement paths or future positions is important for avoiding collisions. The obstacle predictor 226 can predict obstacle trajectories and / or warn the driver or the vehicle planning subsystem 228 of potential collisions. For example, if there is a high likelihood that the trajectory of an obstacle will intersect the current movement path of the vehicle, the obstacle predictor 226 can generate such a warning. The obstacle predictor 226 can use various techniques to make such predictions. These techniques include, for example, constant speed or acceleration models, constant turn rate and speed / acceleration models, models based on Kalman filters and extended Kalman filters, models based on recurrent neural networks (RNNs), models based on long short-term memory (LSTM) neural networks, encoder-decoder RNN models, and the like.

[0059] Still referring Figure 2 , in some embodiments, the vehicle perception and planning system 220 further includes a vehicle planning subsystem 228. The vehicle planning subsystem 228 can include one or more planners, such as a route planner, a driving behavior planner, and a motion planner. The route planner can plan the route of the vehicle based on the vehicle's current location data, target location data, traffic information, and the like. The driving behavior planner uses the obstacle prediction results provided by the obstacle predictor 226 to adjust the timing and planned movement based on how other objects might move. The motion planner determines the specific actions that the vehicle needs to follow. The planning results are then transmitted to the vehicle control system 280 via the vehicle interface 270. The communication can be performed through communication paths 227 and 271, which include any wired or wireless communication links that can transmit data.

[0060] The vehicle control system 280 controls the steering mechanism, throttle, brakes, etc. of the vehicle to operate the vehicle according to the planned route and movement. In some examples, the vehicle perception and planning system 220 may further include a user interface 260 that provides access to the vehicle control system 280 to the user (e.g., the driver) to override or take over control of the vehicle if necessary, for example. The user interface 260 may also be separate from the vehicle perception and planning system 220. The user interface 260 may communicate with the vehicle perception and planning system 220, for example, to obtain and display raw or fused sensor data, identified objects, the position / attitude of the vehicle, etc. The displayed data may help the user better operate the vehicle. The user interface 260 may communicate with the vehicle perception and planning system 220 and / or the vehicle control system 280 via communication paths 221 and 261, respectively, which communication paths include any wired or wireless communication link capable of transmitting data. It should be understood that Figure 2 the various systems, sensors, communication links, and interfaces can be configured in any desired manner and are not limited to Figure 2 the configuration shown.

[0061] Figure 3 is a block diagram illustrating an exemplary LiDAR system 300. The LiDAR system 300 can be used to implement Figure 1 and Figure 2 the LiDAR systems 110, 120A - 120I, and / or 210 shown in. In one embodiment, the LiDAR system 300 includes a light source 310, a transmitter 320, an optical receiver and a photodetector 330, a steering system 340, and a control circuit 350. These components are coupled together using communication paths 312, 314, 322, 332, 342, 352, and 362. These communication paths include communication links (wired or wireless, bidirectional or unidirectional) between the various LiDAR system components, but do not have to be the physical components themselves. Although the communication paths may be implemented by one or more wires, buses, or optical fibers, the communication paths may also be wireless channels or free space optical paths, such that there is no physical communication medium. For example, in one embodiment of the LiDAR system 300, the communication path 314 between the light source 310 and the transmitter 320 may be implemented using one or more optical fibers. The communication paths 332 and 352 may represent optical paths implemented using free space optical components and / or optical fibers. And the communication paths 312, 322, 342, and 362 may be implemented using one or more wires carrying electrical signals. The communication paths may also include one or more of the above types of communication media (e.g., they may include optical fibers and free space optical components, or include one or more optical fibers and one or more wires).

[0062] In some embodiments, the LiDAR system 300 can be a coherent LiDAR system. Frequency-modulated continuous wave (FMCW) LiDAR is an example. Coherent LiDAR detects objects by mixing the returned light from the objects and the light from a coherent laser transmitter. Thus, as Figure 3 shown, if the LiDAR system 300 is a coherent LiDAR, it can include a path 372 that provides a portion of the transmitted light from the transmitter 320 to the optical receiver and photodetector 330. The path 372 can include one or more optical devices (e.g., optical fibers, lenses, mirrors, etc.) for providing the light from the transmitter 320 to the optical receiver and photodetector 330. The transmitted light provided by the transmitter 320 can be modulated light and can be split into two parts. One part is emitted into the FOV, while the second part is sent to the optical receiver and photodetector of the LiDAR system. The second part is also referred to as the light held locally (LO) in the LiDAR system. The transmitted light is scattered or reflected by various objects in the FOV, and at least a portion of it forms the returned light. The returned light is then detected and interfered and recombined with the second part of the transmitted light held locally. Coherent LiDAR provides a mechanism for optically sensing the range of an object and its relative velocity along the line of sight (LOS).

[0063] The LiDAR system 300 can also include Figure 3 other components not shown in, such as a power bus, a power supply, an LED indicator, a switch, etc. Additionally, there can be other communication connections between the components, such as a direct connection between the light source 310 and the optical receiver and photodetector 330 to provide a reference signal so that the time from the emission of the light pulse to the detection until the returned light pulse can be accurately measured.

[0064] The light source 310 outputs a laser for irradiating objects in the field of view (FOV). The laser can be infrared light with a wavelength in the range of 700 nm to 1 mm. The light source 310 can be, for example, a semiconductor-based laser (e.g., a diode laser) and / or a fiber-based laser. The 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 external-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, etc. The fiber-based laser is a laser in which the active gain medium is a fiber doped with rare earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium, and / or holmium. In some embodiments, the fiber laser is based on a double-clad fiber, where 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, enabling the laser source to be a high-power fiber laser source.

[0065] In some embodiments, the light source 310 includes a master oscillator (also referred to as a seed laser) and a power amplifier (MOPA). 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 an external cavity tunable diode laser. In some embodiments, the light source 310 can be an optically pumped microchip laser. A microchip laser is an alignment - free monolithic solid - state laser where the laser crystal is in direct contact with the end mirror of the laser resonator. Microchip lasers are typically pumped by laser diodes (either directly or using optical fibers) to obtain the desired output power. Microchip lasers can be based on a neodymium - doped yttrium aluminum garnet (Y3Al5O12) laser crystal (i.e., Nd:YAG), or a neodymium - doped vanadate (i.e., ND:YVO4) laser crystal. In some examples, the light source 310 can have multiple amplification stages to achieve high - power gain, such that the laser output can have high power, enabling the LiDAR system to have a long scan range. In some examples, the power amplifier of the light source 310 can be controlled such that the power gain can be changed to achieve any desired laser output power.

[0066] Figure 4 A block diagram illustrating an exemplary fiber - based laser source 400 that has a seed laser and one or more pumps (e.g., laser diodes) for pumping to a desired output power. The fiber - based laser source 400 is Figure 3An example of the light source 310 depicted. In some embodiments, the fiber-based laser source 400 includes a seed laser 402 to generate an initial optical pulse of one or more wavelengths (e.g., an infrared wavelength such as 1550 nm), and the initial optical pulse is provided to a wavelength division multiplexer (WDM) 404 via a fiber 403. The fiber-based laser source 400 further includes a pump 406 for providing laser power (e.g., a different wavelength such as 980 nm) to the WDM 404 via a fiber 405. The WDM 404 multiplexes the optical pulse provided by the seed laser 402 and the laser power provided by the pump 406 onto a single fiber 407. Then, the output of the WDM 404 can be provided to one or more preamplifiers 408 via the fiber 407. The preamplifier 408 can be an optical amplifier that amplifies the optical signal (e.g., having a gain of about 10 - 30 dB). In some embodiments, the preamplifier 408 is a low-noise amplifier. The preamplifier 408 outputs to an optical combiner 410 via a fiber 409. The combiner 410 combines the output laser of the preamplifier 408 with the laser power provided by a pump 412 via a fiber 411. The combiner 410 can combine optical signals having the same wavelength or different wavelengths. An example of the combiner is a WDM. The combiner 410 provides the combined optical signal to a booster amplifier 414, which generates an output optical pulse via a fiber 415. The booster amplifier 414 provides further amplification of the optical signal (e.g., another 20 - 40 dB). The output optical pulse can then be emitted to a transmitter 320 and / or a steering mechanism 340 (as Figure 3 shown). It should be understood that Figure 4 illustrates an exemplary configuration of the fiber-based laser source 400. The laser source 400 can have many other configurations with different combinations of one or more components shown in Figure 4 and / or other components not shown in Figure 4 such as other components like power supplies, lenses, filters, beam splitters, combiners, etc.).

[0067] In some variations, the fiber-based laser source 400 can be controlled (e.g., by a control circuit 350) to generate pulses of different amplitudes based on the fiber gain profile of the fiber used in the fiber-based laser source 400. A communication path 312 couples the fiber-based laser source 400 to a control circuitry 350 (as Figure 3as shown), such that the components of the fiber-based laser source 400 can be controlled by or otherwise communicate with the control circuitry 350. Alternatively, the fiber-based laser source 400 can include its own dedicated controller. Instead of the control circuit 350 directly communicating with the components of the fiber-based laser source 400, the dedicated controller of the fiber-based laser source 400 communicates with the control circuit 350 and controls and / or communicates with the components of the fiber-based laser source 400. The fiber-based laser source 400 can also include other components (not shown), such as one or more power connectors, a power supply, and / or power lines.

[0068] Reference Figure 3 , typical operating wavelengths of the light source 310 include, for example, approximately 850 nm, approximately 905 nm, approximately 940 nm, approximately 1064 nm, and approximately 1550 nm. For laser safety, the upper limit of the maximum available laser power is set by U.S. Food and Drug Administration (FDA) regulations. The optical power limit at a wavelength of 1550 nm is much higher than the optical power limits of the other wavelengths mentioned above. Additionally, at 1550 nm, the optical power loss in the fiber is very low. These characteristics at a wavelength of 1550 nm make it more favorable for long-range LiDAR applications. The amount of optical power output from the light source 310 can be characterized by its peak power, average power, pulse energy, and / or pulse energy density. Peak power is the ratio of pulse energy to pulse width (e.g., full width at half maximum or FWHM). Thus, for a fixed amount of pulse energy, a smaller pulse width can provide a larger peak power. The pulse width can be in the range of nanoseconds or picoseconds. Average power is the product of pulse energy and pulse repetition rate (PRR). As described in more detail below, the PRR represents the frequency of the pulsed laser. Generally, the smaller the time interval between pulses, the higher the PRR. The PRR typically corresponds to the maximum range that the LiDAR system can measure. The light source 310 can be configured to generate pulses at a high PRR to meet the desired number of data points in the point cloud generated by the LiDAR system. The light source 310 can also be configured to generate pulses at a medium or low PRR to meet the desired maximum detection range. Wall plug efficiency (WPE) is another factor for evaluating the total power consumption, and it can be a useful metric for evaluating the efficiency of the laser. For example, as Figure 1 shown, multiple LiDAR systems can be attached to a vehicle, which can be an electric vehicle or a vehicle with limited fuel or battery power. Therefore, high WPE and an intelligent way of using laser power are generally important considerations when selecting and configuring the light source 310 and / or designing the laser delivery system for in-vehicle LiDAR applications.

[0069] It should be understood that the above description provides a non-limiting example of the light source 310. The 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 external cavity tunable diode lasers), which are configured to generate one or more optical signals at various wavelengths. In some examples, the light source 310 includes an amplifier (e.g., a pre-amplifier and / or a booster amplifier), which can be a doped fiber amplifier, a solid-state amplifier, and / or a semiconductor optical amplifier. The amplifier is configured to receive and amplify the optical signal with a desired gain.

[0070] Return reference Figure 3 , the LiDAR system 300 further includes a transmitter 320. The light source 310 provides laser light (e.g., in the form of a laser beam) to the transmitter 320. The laser light provided by the light source 310 can be amplified laser light having a pre-determined or controlled wavelength, pulse repetition rate, and / or power level. The transmitter 320 receives the laser light from the light source 310 and emits the laser light with a low divergence to the steering mechanism 340. In some embodiments, the transmitter 320 can include, for example, optical components (e.g., lenses, optical fibers, mirrors, etc.) for emitting one or more laser beams directly or via the steering mechanism 340 into the field of view (FOV). Although Figure 3 the transmitter 320 and the steering mechanism 340 are illustrated as separate components, in some embodiments, they can be combined or integrated into one system. The steering mechanism 340 will be described in more detail below.

[0071] The laser beam provided by the light source 310 may diverge as it propagates to the transmitter 320. Therefore, the transmitter 320 typically includes a collimating lens, which is configured to collect the diverging laser beam and produce a more parallel beam with a reduced or minimized divergence. The collimated beam can then be further directed through various optical devices, such as mirrors and lenses. The collimating lens can be, for example, a single plano-convex lens or a lens group. The collimating lens can be configured to achieve any desired characteristics, such as beam diameter, divergence, numerical aperture, focal length, etc. The beam propagation ratio or beam quality factor (also known as the M 2 factor) is used to measure the quality of the laser beam. In many LiDAR applications, it is important to have good laser beam quality in the generated transmitted laser beam. The M 2 factor represents the degree of variation of the beam with respect to an ideal Gaussian beam. Therefore, the M 2 factor reflects how well the collimated laser beam can be focused on a small spot, or how well the diverging laser beam can be collimated. Therefore, the light source 310 and / or the transmitter 320 can be configured to meet, for example, the scanning resolution requirements while maintaining a desired M 2 factor.

[0072] One or more of the light beams provided by the emitter 320 are scanned into the FOV by the steering mechanism 340. The steering mechanism 340 scans the light beam in multiple dimensions (e.g., in the horizontal dimension and the vertical dimension) to facilitate the LiDAR system 300 to map the environment by generating a 3D point cloud. The horizontal dimension may be a dimension parallel to the horizon or a surface associated with the LiDAR system or the vehicle (e.g., the road surface). The vertical dimension is perpendicular to the horizontal dimension (i.e., the vertical dimension forms a 90-degree angle with the horizontal dimension). The steering mechanism 340 will be described in more detail below. The laser scanned into the FOV may be scattered or reflected by an object in the FOV. At least a portion of the scattered light or reflected light forms the return light that returns to the LiDAR system 300. Figure 3 Further illustrated is an optical receiver and a photodetector 330 configured to receive the return light. The optical receiver and the photodetector 330 include an optical receiver configured to collect the return light from the FOV. The optical receiver may include optical devices (e.g., lenses, optical fibers, mirrors, etc.) for receiving, redirecting, focusing, amplifying, and / or filtering the return light from the FOV. For example, the optical receiver typically includes a collection lens (e.g., a single plano-convex lens or a lens group) to collect the return light and / or focus the collected return light onto the photodetector.

[0073] The photodetector detects the return light focused by the optical receiver and generates a current and / or voltage signal 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. An exemplary method for deriving such depth information is based on direct TOF (time of flight), which will be described in more detail below. The photodetector can be characterized by its detection sensitivity, quantum efficiency, detector bandwidth, linearity, signal-to-noise ratio (SNR), anti-overload ability, anti-interference ability, etc. Based on the application, the photodetector can be configured or customized to have any desired characteristics. For example, the optical receiver and the photodetector 330 can be configured such that the photodetector has a large dynamic range while having good linearity. Photodetector linearity indicates the ability of the detector to maintain a linear relationship between the input optical signal power and the detector output. A detector with good linearity can maintain a linear relationship within a large dynamic input optical signal range.

[0074] To achieve desired detector characteristics, the structure of the photodetector and / or the material system of the detector can be configured or customized. Various detector structures can be used for the photodetector. For example, the photodetector structure can be a PIN-based structure that has an undoped intrinsic semiconductor region (i.e., the "I" region) between the p-type semiconductor and the n-type semiconductor regions. Other photodetector structures include, for example, APD (avalanche photodiode)-based structures, PMT (photomultiplier tube)-based structures, SiPM (silicon photomultiplier)-based structures, SPAD (single photon avalanche diode)-based structures, and / or quantum wires. For the material system used in the photodetector, Si, InGaAs, and / or Si / Ge-based materials can be used. It should be understood that many other detector structures and / or material systems can be used in the optical receiver and the photodetector 330.

[0075] A photodetector (e.g., an APD-based detector) can have internal gain such that the input signal is amplified when an output signal is generated. However, due to the internal gain of the photodetector, noise can also be amplified. Common types of noise include signal shot noise, dark current shot noise, thermal noise, and amplifier noise. In some embodiments, the optical receiver and the photodetector 330 can include a preamplifier of a low-noise amplifier (LNA). In some embodiments, the preamplifier can further include a transimpedance amplifier (TIA) that converts a current signal into a voltage signal. For a linear detector system, the input equivalent noise or the noise equivalent power (NEP) measures the sensitivity of the photodetector to weak signals. Thus, they can be used as an indicator of the overall system performance. For example, the NEP of a photodetector specifies the power of the weakest signal that can be detected, and thus it in turn specifies the maximum range of the LiDAR system. It should be understood that various photodetector optimization techniques can be used to meet the requirements of the LiDAR system 300. Such optimization techniques can include selecting different detector structures, materials, and / or implementing signal processing techniques (e.g., filtering, noise reduction, amplification, etc.). For example, in addition to or instead of using direct detection of the returned signal (e.g., by using ToF), coherent detection can also be used for the photodetector. Coherent detection allows the detection of the amplitude and phase information of the received light by interfering the received light with a local oscillator. Coherent detection can improve the detection sensitivity and the noise immunity.

[0076] Figure 3The LiDAR system 300 is further illustrated to include a steering mechanism 340. As described above, the steering mechanism 340 directs the light beam from the transmitter 320 for multi-dimensional scanning of the FOV. The steering mechanism is referred to as a raster mechanism, a scanning mechanism, or simply an optical scanner. Scanning the light beam in multiple directions (e.g., in the horizontal and vertical directions) facilitates the LiDAR system to map the environment by generating an image or a 3D point cloud. The 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 rotates the LiDAR transmitter and receiver (collectively referred to as the transceiver) to scan the laser beam. Solid-state scanning guides the laser beam to various positions across the FOV without mechanically moving any macroscopic components, such as the transceiver. Solid-state scanning mechanisms include, for example, steering based on optical phased arrays and flash LiDAR-based steering. In some embodiments, since the solid-state scanning mechanism does not physically move macroscopic components, the steering performed by the solid-state scanning mechanism can be referred to as virtual steering. A LiDAR system using solid-state scanning can also be referred to as a non-mechanical scanning or simply a non-scanning LiDAR system (a flash LiDAR system is an exemplary non-scanning LiDAR system).

[0077] The steering mechanism 340 can be used in conjunction with the transceiver (e.g., the transmitter 320 and the optical receiver and photodetector 330) to scan the FOV for generating an image or a 3D point cloud. As an example, to implement the steering mechanism 340, a two-dimensional mechanical scanner can be used in conjunction with a single-point or a few single-point transceivers. The single-point transceiver emits a single light beam or a small number of light beams (e.g., 2 - 8 light beams) into the steering mechanism. Two-dimensional mechanical steering mechanisms include, for example, polygon mirrors, oscillating mirrors, rotating prisms, rotating tilted mirrors, single-plane or multi-plane mirrors, or combinations thereof. In some embodiments, the steering mechanism 340 can include a non-mechanical steering mechanism, such as a solid-state steering mechanism. For example, the steering mechanism 340 can be based on the tuned wavelength of the laser that combines the refraction effect, and / or based on a reconfigurable grating / phase array. In some embodiments, the steering mechanism 340 can use a single scanning device to achieve two-dimensional scanning, or use a combination of multiple scanning devices to achieve two-dimensional scanning.

[0078] As another example, to implement the steering mechanism 340, a one-dimensional mechanical scanner can be used in conjunction with an array or a large number of single-point transceivers. Specifically, the transceiver array can be mounted on a rotating platform to achieve a 360-degree horizontal field of view. Alternatively, a static transceiver array can be combined with a one-dimensional mechanical scanner. One-dimensional mechanical scanners include polygon mirrors, oscillating mirrors, rotating prisms, rotating tilted mirrors, or combinations thereof, for obtaining a forward horizontal field of view. The steering mechanism using a mechanical scanner can provide robustness and reliability in large-scale production for automotive applications.

[0079] As another example, to implement the steering mechanism 340, a two-dimensional transceiver can be used to directly generate a scanned image or a 3D point cloud. In some embodiments, stitching or micro-displacement methods can be used to increase the resolution of the scanned image or the field of view being scanned. For example, using a two-dimensional transceiver, the signals generated in one direction (e.g., the horizontal direction) and the signals generated in another direction (e.g., the vertical direction) can be integrated, interleaved, and / or matched to generate a higher or full-resolution image or 3D point cloud representing the scanned FOV.

[0080] Some implementations of the steering mechanism 340 include one or more optical redirecting elements (e.g., mirrors or lenses) that steer the returned optical signal along the receiving path (e.g., by rotation, vibration, or guiding) to direct the returned optical signal to the optical receiver and photodetector 330. The optical redirecting elements that guide the optical signal along the emission path and the receiving path can be the same component (e.g., shared), separate components (e.g., dedicated), and / or a combination of shared and separate components. This means that in some cases, the emission path and the receiving path are different, although they may partially overlap (or in some cases, substantially overlap or completely overlap).

[0081] Still referring to Figure 3 , the LiDAR system 300 further includes control circuitry 350. The control circuit 350 can be configured and / or programmed to control various parts of the LiDAR system 300 and / or perform signal processing. In a typical system, the control circuit 350 can be configured and / or programmed to perform one or more control operations, including, for example, controlling the light source 310 to obtain desired laser pulse timing, pulse repetition rate, and power; controlling the steering mechanism 340 (e.g., controlling speed, direction, and / or other parameters) to scan the FOV and maintain pixel registration and / or alignment; controlling the optical receiver and photodetector 330 (e.g., controlling sensitivity, noise reduction, filtering, and / or other parameters) such that it is in an optimal state; and monitoring the overall system health / functional safety state (e.g., monitoring the safety of the laser output power and / or the operating state of the steering mechanism).

[0082] The control circuitry 350 can also be configured and / or programmed to perform signal processing on the raw data generated by the optical receiver and photodetector 330 to obtain distance and reflectivity information, and perform data packing and communication with the vehicle perception and planning system 220, such as Figure 2Communication as shown). For example, the control circuit 350 determines the time taken from transmitting an optical pulse to receiving the corresponding returned optical pulse; determines when no returned optical pulse of the transmitted optical pulse is received; determines the direction of the transmitted optical pulse / returned optical pulse (e.g., horizontal information and / or vertical information); determines the estimated range in a specific direction; derives the reflectivity of an object in the FOV, and / or determines any other type of data related to the LiDAR system 300.

[0083] The LiDAR system 300 can be disposed in a vehicle, which can operate in many different environments, including hot or cold weather, rough road conditions that may cause strong vibrations, high or low humidity, dusty areas, etc. Thus, in some embodiments, the optical and / or electronic components of the LiDAR system 300 (e.g., the optics in the transmitter 320, the optical receiver and the photodetector 330, and the steering mechanism 340) are arranged and / or configured in a manner that maintains long-term mechanical and optical stability. For example, the components in the LiDAR system 300 can be fixed and sealed so that they can operate under all conditions that the vehicle may encounter. As an example, a moisture-proof coating and / or an airtight seal can be applied to the optical components of the transmitter 320, the optical receiver and the photodetector 330, and the steering mechanism 340 (and other moisture-sensitive components). As another example, a housing, a shroud, a fairing, and / or a window can be used in the LiDAR system 300 to provide desired characteristics such as hardness, ingress protection (IP) rating, self-cleaning ability, chemical resistance, and impact resistance, etc. Additionally, an efficient and economical method for assembling the LiDAR system 300 can be used to meet the LiDAR operation requirements while maintaining a low cost.

[0084] Those of ordinary skill in the art should understand that Figure 3 and the above description is for illustrative purposes only, and the LiDAR system can include other functional units, blocks, or segments, and can include variations or combinations of these above functional units, blocks, or segments. For example, the LiDAR system 300 can also include Figure 3 other components not depicted in, such as a power bus, a power supply, an LED indicator, a switch, etc. Additionally, there can be other connections between components, such as a direct connection between the light source 310 and the optical receiver and the photodetector 330, so that the photodetector 330 can accurately measure the time from when the light pulse is emitted from the light source 310 until the photodetector 330 detects the returned light pulse.

[0085] Figure 3The components shown are coupled together using communication paths 312, 314, 322, 332, 342, 352, and 362. These communication paths represent communication (bidirectional or unidirectional) between various LiDAR system components, but do not have to be the physical components themselves. Although the communication paths can be implemented by one or more wires, buses, or optical fibers, the communication paths can also be wireless channels or free-space optical paths, such that there is no physical communication medium. For example, in an exemplary 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 wires that carry electrical signals. The communication paths can also include more than one of the types of communication media described above (e.g., they can include optical fibers and optical paths, or one or more optical fibers and one or more wires).

[0086] As described above, some LiDAR systems use the time-of-flight (ToF) of optical signals (e.g., light pulses) to determine the distance to an object in the optical path. For example, referring to Figure 5A , exemplary 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 having one or more optical devices). LiDAR system 500 can be implemented using, for example, the above-described LiDAR system 300. LiDAR system 500 emits light pulses 502 along an optical path 504 determined by the steering mechanism of LiDAR system 500. In the depicted example, the light pulses 502 generated by the laser light source are short pulses of laser light. Additionally, the signal manipulation mechanism of LiDAR system 500 is a pulsed signal steering mechanism. However, it should be understood that a LiDAR system can operate by generating, emitting, and detecting non-pulsed optical signals and using techniques other than time-of-flight to derive the distance to an object in the surrounding environment. For example, some LiDAR systems use frequency-modulated continuous wave (i.e., "FMCW"). It should also be understood that any techniques described herein for time-of-flight-based systems using pulsed signals can also be applicable to LiDAR systems that do not use one or both of these techniques.

[0087] Return reference Figure 5A(For example, a time-of-flight LiDAR system using optical pulses is illustrated), when the optical pulse 502 reaches the object 506, the optical pulse 502 scatters or reflects to form a returned optical pulse 508. The returned optical pulse 508 can return to the system 500 along the optical path 510. The time from when the emitted optical pulse 502 leaves the LiDAR system 500 to when the returned optical pulse 508 returns to the LiDAR system 500 can be measured (e.g., by a processor or other electronic device within the LiDAR system, such as the control circuit 350). This time of flight combined with the knowledge of the speed of light can be used to determine the distance / distance from the LiDAR system 500 to the part of the object 506 where the optical pulse 502 is scattered or reflected.

[0088] By directing a number of optical pulses, such as Figure 5B depicted, the LiDAR system 500 scans the external environment (e.g., by directing the optical pulses 502, 522, 526, 530 along the optical paths 504, 524, 528, 532 respectively). As Figure 5C depicted, the LiDAR system 500 receives the returned optical pulses 508, 542, 548 (corresponding to the emitted optical pulses 502, 522, 530 respectively). The returned optical pulses 508, 542, and 548 are formed by scattering or reflecting the emitted optical pulses by one of the objects 506 and 514. The returned optical pulses 508, 542, and 548 can return to the LiDAR system 500 along the optical paths 510, 544, and 546 respectively. Based on the direction of the emitted optical pulses (as determined by the LiDAR system 500) and the calculated distance from the LiDAR system 500 to the part of the object that scatters or reflects the optical pulse (e.g., parts of the objects 506 and 514), the external environment within the detectable range (e.g., the field of view between the paths 504 and 532, including) can be accurately mapped or drawn (e.g., by generating a 3D point cloud or an image).

[0089] If no corresponding optical pulse is received for a particular emitted optical pulse, the LiDAR system 500 can determine that there is no object within the detectable range of the LiDAR system 500 (e.g., the object is outside the maximum scan distance of the LiDAR system 500). For example, in Figure 5B , the optical pulse 526 may not have a corresponding returned optical pulse (as Figure 5C illustrated), because the optical pulse 526 may not produce a scattering event along its transmission path 528 within a pre-determined detection range. The LiDAR system 500 or an external system communicating with the LiDAR system 500 (e.g., a cloud system or service) can interpret the absence of a returned optical pulse as there being no object along the optical path 528 within the detectable range of the LiDAR system 500.

[0090] InFigure 5B In this case, the optical pulses 502, 522, 526, and 530 can be emitted in any order, serially, in parallel, or based on other timings relative to each other. Additionally, although Figure 5B the emitted optical pulses are depicted as being directed in one dimension or one plane (e.g., the plane of the paper), the LiDAR system 500 can also direct the emitted optical pulses along other dimensions or planes. For example, the LiDAR system 500 can also direct the emitted optical pulses in a dimension or plane perpendicular to Figure 5B the dimension or plane shown, thereby forming a two-dimensional transmission of the optical pulses. This two-dimensional transmission of the optical pulses can be point-by-point, line-by-line, all-at-once, or otherwise. That is, the LiDAR system 500 can be configured to perform point scanning, line scanning, non-scanning single scanning, or a combination thereof. A point cloud or image from a one-dimensional transmission of the optical pulses (e.g., a single horizontal line) can generate two-dimensional data (e.g., (1) data from the horizontal transmission direction and (2) the range or distance to the object). Similarly, a point cloud or image from a two-dimensional transmission of the optical pulses can generate three-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 the object). Generally, a LiDAR system that performs an n-dimensional transmission of optical pulses generates (n + 1)-dimensional data. This is because the LiDAR system can measure the depth or the distance to the object, which provides an additional data dimension. Thus, a 2D scan performed by the LiDAR system can generate a 3D point cloud for mapping the external environment of the LiDAR system.

[0091] The density of the point cloud refers to the number of measurements (data points) in each area performed by the LiDAR system. The point cloud density is related to the LiDAR scan resolution. Generally, at least for the region of interest (ROI), a greater point cloud density is desired and thus a higher resolution is required. The point density in the point cloud or image generated by the 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. Thus, in order to increase the density of the points generated by a set of transmit-receive optics (or transceiver optics), the LiDAR system may need to generate pulses more frequently. In other words, the light source in the LiDAR system can have a higher pulse repetition rate (PRR). On the other hand, by generating and emitting pulses more frequently, the maximum 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 emits the next pulse, the return signal may be detected in an order different from the order in which the corresponding signal was emitted, resulting in ambiguity if the system cannot correctly correlate the return signal with the emitted signal.

[0092] For illustration, consider an exemplary LiDAR system that can emit 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 confusion of return pulses from consecutive pulses in a typical LiDAR design, for 500 kHz and 1 MHz, the maximum distances that the LiDAR system can detect can be 300 meters and 150 meters respectively. The point density of a LiDAR system with a repetition frequency of 500 kHz is half that of 1 MHz. Thus, this example shows that increasing the repetition rate from 500 kHz to 1 MHz (and thus increasing the point density of the system) may decrease the detection range of the system if the system cannot correctly correlate the return signals that arrive out of order. Various techniques are used to mitigate the trade - off between a higher PRR and a limited detection range. For example, multiple wavelengths can be used to detect objects at different ranges. Optical and / or signal processing techniques (e.g., pulse coding techniques) are also used to correlate the transmitted optical signal with the returned optical signal.

[0093] The various systems, devices, and methods described herein can be implemented using digital circuits or using one or more computers that utilize well - known computer processors, memory units, storage devices, computer software, and other components. Generally, a computer includes a processor for executing instructions and one or more memories for storing the instructions and data. The computer may also include or be coupled to one or more mass storage devices, such as one or more disks, internal hard drives and removable disks, magneto - optical disks, optical disks, etc.

[0094] The various systems, devices, and methods described herein can be implemented using computers operating in a client - server relationship. Generally, in such a system, the client computer is located at a location remote from the server computer and interacts via a network. The client - server relationship can be defined and controlled by computer programs running on the respective client and server computers. Examples of client computers can include desktop computers, workstations, portable computers, cellular smartphones, tablets, or other types of computing devices.

[0095] The various systems, devices, and methods described herein can be implemented using a computer program product that is tangibly embodied in an information carrier, such as in a non - transitory machine - readable storage device, for execution by a programmable processor; and the method processes and steps described herein (including Figures 1 to 13One or more steps (of at least some of them) can be implemented using one or more computer programs 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 specific activity or produce a specific 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.

[0096] Figure 6 FIG. illustrates a simplified block diagram of an exemplary apparatus that can be used to implement the systems, devices, and methods described herein. Apparatus 600 includes 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 these operations. The computer program instructions can be stored in the persistent storage device 620 or other computer-readable media and loaded into the main memory device 630 when it is desired to execute the computer program instructions. For example, processor 610 can be used to implement one or more components and systems described herein, such as control circuitry 350 ( Figure 3 as shown), vehicle perception and planning system 220 ( Figure 2 as shown), and vehicle control system 280 ( Figure 2 as shown). Thus, Figures 1 to 13 at least some of the method steps can be defined by computer program instructions stored in the main memory device 630 and / or the persistent storage device 620 and controlled by processor 610 that executes the computer program instructions. For example, the computer program instructions can be implemented as computer-executable code programmed by those skilled in the art to execute an algorithm defined by the method steps discussed in conjunction with Figures 1 to 13 at least some of them. Accordingly, by executing the computer program instructions, processor 610 executes the algorithm defined by the method steps of these foregoing figures. Apparatus 600 also includes one or more network interfaces 680 for communicating with other devices via a network. Apparatus 600 can also include one or more input / output devices 690 that enable a user to interact with apparatus 600 (e.g., a display, keyboard, mouse, speakers, buttons, etc.).

[0097] The processor 610 may include both a general-purpose microprocessor and a special-purpose microprocessor, and may be the sole processor of the device 600 or one of multiple processors. The processor 610 may include one or more central processing units (CPUs) and one or more graphics processing units (GPUs), and the GPU may, for example, work separately from one or more CPUs and / or perform multitasking with one or more CPUs to accelerate processing, for example, for various image processing applications described herein. The processor 610, the persistent storage device 620, and / or the main memory device 630 may include one or more application-specific integrated circuits (ASICs) and / or one or more field-programmable gate arrays (FPGAs), or be supplemented by one or more ASICs and / or one or more FPGAs, or incorporated into one or more ASICs and / or one or more FPGAs.

[0098] The persistent storage device 620 and the main memory device 630 each include a tangible non-transitory computer-readable storage medium. The persistent storage device 620 and the 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, for example, one or more disk storage devices, such as internal hard disks and removable disks, magneto-optical storage devices, optical disc storage devices, flash memory devices, semiconductor storage 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) discs, or other non-volatile solid-state storage devices.

[0099] The input / output device 690 may include peripheral devices, such as printers, scanners, displays, etc. For example, the input / output device 690 may include a display device (such as a cathode ray tube (CRT), plasma, or liquid crystal display (LCD) monitor) for displaying information to the user, a keyboard, and a pointing device (such as a mouse or trackball) that the user may use to provide input to the device 600.

[0100] Any or all of the functions of the systems and devices discussed herein may be performed by the processor 610 and / or incorporated into a device or system such as the LiDAR system 300. Additionally, the LiDAR system 300 and / or the device 600 may utilize one or more neural networks or other deep learning techniques performed by the processor 610 or other systems or devices discussed herein.

[0101] Those skilled in the art will recognize that the implementation of an actual computer or computer system may have other structures and may also include other components, and Figure 6 is a simplified representation of some of the components of such a computer for illustrative purposes.

[0102] A LiDAR system includes a plurality of transmitter channels configured to emit a plurality of transmitted beams. When the transmitted beams propagate to illuminate one or more objects in the FOV, at least a portion of the transmitted beams is reflected or scattered to form return light. The LiDAR system further includes a plurality of detector elements on the receiver side, the plurality of detector elements being configured to detect the return light. In one example, the plurality of detector elements may be an array of avalanche photodiodes (APDs). The plurality of transmitter channels and the plurality of detector elements are part of a transceiver and are sometimes collectively referred to as the transceiver. Transceiver alignment is desired in the LiDAR system such that the plurality of detector elements can collect as much of the return light formed based on the transmitted beams as possible, thereby achieving high sensitivity of the LiDAR system.

[0103] Figure 7A and Figure 7B are diagrams illustrating examples of devices 700 and 710 for transceiver alignment in a LiDAR system according to some embodiments. As Figure 7A shown, device 700 includes a detector package 701 and a plurality of detector elements 702 mounted to the detector package 701. Figure 7A Only four detector elements 702 in the detector package 701 are illustrated, but it should be understood that more or fewer detector elements may be included in the detector package. The plurality of detector elements 702 are configured to detect the return light and can be used to implement the Figure 3 shown optical receiver and photodetector 330. In one example, the plurality of detector elements 702 may be an APD array of a group of APDs. The term "array" in the present disclosure means that the detector elements 702 are arranged in a specific manner, which may or may not correspond to the detector elements 702 being arranged in a row (e.g., in a straight line) with each other. In some embodiments, as Figure 7A shown, the plurality of detector elements 702 form a one-dimensional array of detector elements. Device 700 further includes a light-forming mark 703 mounted to the detector package 701. In some embodiments, the detector package 701 further includes a printed circuit board (PCB). The light-forming mark 703 is disposed on the PCB. As Figure 7AAs shown, the light - formed marker 703 includes a rectangular marker. In some embodiments, the light - formed marker 703 includes a marker having one or more designs, and the one or more designs include a linear design, a rectangular design, a circular design, an oval design, a polygonal design, a barcode design, a QR - code design, and any free - form shape design. As Figure 7A shown, the light - formed marker 703 is disposed at a predetermined position relative to the plurality of detector elements 702. The predetermined position of the light - formed marker 703 is predetermined to facilitate alignment of each of the plurality of detector elements 702 with a corresponding emitter channel ( Figure 7A not shown) in the plurality of emitter channels. This will be described in further detail below with reference to Figures 8A to 8C further details.

[0104] Figure 7B FIG. illustrates another example device 710 for transceiver alignment in a LiDAR system. Similar to Figure 7A , the device 710 includes a detector package 701 and a plurality of detector elements 702 mounted to the detector package 701. As Figure 7B shown, the plurality of detector elements 702 form a two - dimensional array of detector elements. The device 710 further includes a light - formed marker 703 disposed at a predetermined position relative to the plurality of detector elements 702. The predetermined position is configured to facilitate transceiver alignment.

[0105] Figures 8A to 8C is a diagram illustrating an example of transceiver alignment using a light - formed marker according to some embodiments. As Figures 8A to 8C shown, the LiDAR system includes a transceiver 820. The transceiver 820 includes a plurality of emitter channels 822 configured to emit a plurality of transmitted beams 830. The plurality of emitter channels 822 can be used to implement Figure 3 the emitter 320 shown. The plurality of transmitted beams 830 have a wavelength λt, which is the operating wavelength of the transceiver 820. In one example, during the manufacture or testing of the transceiver and / or the LiDAR system, one or more imaging devices can be disposed in the transmission optical path of the transceiver 820. The one or more imaging devices can be used to facilitate transceiver alignment. During the normal operation of the LiDAR system, imaging devices may not be required. As Figures 8A to 8C shown, the plurality of transmitted beams 830 are directed towards an imaging device 850 (as Figures 8A to 8B shown) or an imaging device 850a (as Figure 8C shown). Thus, the imaging device 850 (or Figure 8C the imaging device 850a shown) receives the transmitted beams 830 and forms an image 853. As Figures 8A to 8C shown, the transceiver 820 further includes optics 823. In as Figure 8Aand Figure 8B In some embodiments shown, the optical device 823 has an opening 824. In some embodiments, the opening 824 can be a rectangular opening, a circular opening, a square opening, a slot, a hole, a slit, or an opening of any other shape. As Figure 8A and Figure 8B shown, the opening 824 extends from the curved front surface of the optical device 823 to the flat rear surface. A plurality of emitter channels 822 optically coupled to the optical device 823 are at least partially disposed in or near the opening 824. Due to the opening 824, a plurality of transmitted light beams 830 can be transmitted through the optical device 823 toward the imaging device 850 (or Figure 8C the imaging device 850a shown). In some embodiments shown as Figure 8C shown, the optical device 823 can have a small size and thus is not positioned in the transmission optical path. Other arrangements of the optical device 823 and the emitter channels 822 can also be configured such that the optical device 823 does not interfere with the light beam 830.

[0106] As Figures 8A to 8C shown, the transceiver 820 further includes a plurality of detector elements 811 mounted to the detector package 810. The detector elements 811 and the package 810 can be substantially the same as or similar to the detector elements 702 and the detector package 701 shown as Figure 7A and Figure 7B shown. When the LiDAR system operates to scan the FOV, the transmitted light beam 830 propagates to illuminate one or more objects in the FOV. At least a portion of the transmitted light beam 830 is reflected or scattered to form return light (not shown). The plurality of detector elements 811 are configured to detect the return light formed based on the transmitted light beam 830. The plurality of detector elements 811 can be used to implement the optical receiver and the photodetector 330 shown as Figure 3 shown, or as a part thereof. However, when performing transceiver alignment, the transmitted light beam 830 is directed to the imaging device 850 shown as Figures 8A to 8B or the imaging device 850a shown as Figure 8C shown. During the transceiver alignment process, the LiDAR system does not scan, and thus no return light signal is shown as Figures 8A to 8C shown. After performing the transceiver alignment process, the LiDAR system operates to scan the FOV and receives the return light 811 through the detector elements. In some examples, the plurality of detector elements 811 sense light but do not emit light, the detector elements 811. Thus, during the transceiver alignment process, the detector elements 811 do not form an image in the imaging device 850. As Figures 8A to 8B shown, a plurality of dashed boxes 851 illustrate in the imaging device 850 (or Figure 8CPossible positions of the plurality of detector elements 811 imaged in the imaging device 850a) shown, assuming a situation where they can be imaged. As Figures 8A to 8C shown, the LiDAR system further includes one or more light - forming marks mounted to the detector package 810 for transceiver alignment. In some embodiments, the detector package 810 further includes a PCB. The light - forming marks are disposed on the PCB. An example of the transceiver alignment process using the light - forming marks is described in more detail below.

[0107] Figure 8A Illustrates an example of transceiver alignment in a LiDAR system according to some embodiments. As Figure 8A shown, the light - forming marks 812 (e.g., Figure 7A and Figure 7B the light - forming marks 703 shown) are mounted to the detector package 810. Figure 8A Only two such light - forming marks 812a and 812b are illustrated, but it should be understood that more or fewer light - forming marks 812 may be included. The light - forming marks 812a and 812b are collectively referred to as the light - forming marks 812. As Figure 8A shown, the light - forming marks 812 include rectangular marks. In some embodiments, the light - forming marks 812 include marks having one or more designs, the one or more designs including linear designs, rectangular designs, circular designs, oval designs, polygonal designs, barcode designs, QR - code designs, and any free - form shape designs. In some embodiments such as Figure 8A shown, the light - forming marks 812 include light - emitting devices electrically coupled to one or more electrodes 813a and 813b (collectively referred to as electrodes 813). The electrodes 813 are configured to provide electrical signals during the transceiver alignment process that cause the light - forming marks 812a and 812b to emit light 840a and 840b (collectively referred to as light 840), respectively. Such light - forming marks 812 are thus referred to as active light - forming marks. In some embodiments, when the LiDAR system is performing a scan, the electrodes 813 are turned off and thus do not provide electrical signals to the light - forming marks 812. Thus, during normal operation of the LiDAR system, the light - forming marks 812 do not emit light, which may interfere with the light detection of the LiDAR. In some embodiments, the light - emitting devices for the light - forming marks 812 include one or more of edge - emitting lasers (EELs), vertical - cavity surface - emitting lasers (VCSELs), light - emitting diodes (LEDs), and photonic - crystal surface - emitting lasers (PCSELs). As Figure 8AAs shown, the light-forming marker 812 emits light 840 towards the imaging device 850. Thus, images 852a and 852b (collectively referred to as image 852) of the light-forming markers 812a and 812b are formed in the imaging device 850. In some embodiments, depending on the optical path, the optical device 823 can be used for one or both of collimation and focusing. For example, for the optical path used in transceiver alignment, the optical device 823 can be a collimating lens configured to collimate the light 840. During normal operation of the LiDAR system, the optical device 823 can be a collection lens or a focusing lens configured to focus the returned light onto the detector element 811. Figure 8A Illustrated are two images 852a and 852b corresponding respectively to two light-forming markers 812a and 812b. It should be understood that if there are more or fewer light-forming markers 812 in the detection package 810, more or fewer images 852 are formed in the imaging device 850.

[0108] As Figure 8A shown, the light 840a provided by the light-forming marker 812a has a wavelength λma. The light 840b provided by the light-forming marker 812b has a wavelength λmb. In some embodiments, the wavelength λma of the light 840a is different from the wavelength λmb of the light 840b (i.e., λma≠λmb). Because the lights 840a and 840b have different wavelengths, they have different focal lengths. In one example, in order to properly form images of the lights 840a and 840b with different wavelengths on the same imaging device 850, the light-forming marker 812a and the light-forming marker 812b can be placed at different heights or different distances from the imaging device 850. As Figure 8A shown, the h-axis in the coordinate system represents the horizontal direction, the y-axis represents the vertical direction, and the x-axis represents the direction perpendicular to the paper plane. The height difference or distance difference between the light-forming markers 812a and 812b is shown as different positions of the markers 812a and 812b along the h-axis. When placed at different positions or distances from the imaging device 850, the lights 840a and 840b with different wavelengths can be properly focused onto the imaging device 850, and thus clear images are formed. In some embodiments as Figure 8A shown, the LiDAR system can further include an optical device 870 (e.g., a lens or a lens group), which is configured to facilitate image formation in the imaging device 850. Alternatively, the optical devices 823 and / or 870 can be achromatic lenses, which are configured to direct the lights 840a and 840b with different wavelengths to properly form images on the same imaging device 850.

[0109] In some embodiments, the light 840 (840a or 840b) formed by the light-forming marker 812 may have a wavelength different from the operating wavelength of the transceiver 820 (i.e., for the wavelength λt of the plurality of transmitted light beams 830, λma≠λt, and / or λmb≠λt). In order to correctly form the images of the light 830 and 840 with different wavelengths on the same imaging device 850, the light-forming marker 812 and the plurality of detector elements 811 may have different heights or different distances from the imaging device 850. As Figure 8A shown, the height difference or distance difference between the light-forming marker 812 and the plurality of detector elements 811 is shown as their different positions along the h-axis. For example, the marker 812 may be placed closer to the imaging device 850 compared to the detector element 811, and vice versa. Alternatively, the optical devices 823 and / or 870 may be achromatic lenses configured to direct the light 830 and 840 with different wavelengths to form an image on the same imaging device 850. In some embodiments, the light 840 (light 840a and 840b) formed by the light-forming marker 812 has a wavelength substantially the same as the operating wavelength of the transceiver 820 (i.e., the wavelength λt of the plurality of transmitted light beams 830; λma = λmb = λt). In this case, the light-forming marker 812 and the plurality of detector elements 811 may be placed at the same height or the same distance from the imaging device 850.

[0110] As Figure 8A shown, based on the alignment requirements of the plurality of detector elements 811, the light-forming marker 812 is disposed at a predetermined position relative to the plurality of detector elements 811. The predetermined position of the light-forming marker 812 is configured to facilitate the alignment of each of the plurality of detector elements 811 with a corresponding emitter channel among the plurality of emitter channels 822. Based on the image 853 of the transmitted light beam 830 and the image 852 of the light-forming marker 812, the plurality of emitter channels 822 may be aligned relative to the plurality of detector elements 811. As Figure 8A shown, if the image 853 of the transmitted light beam 830 is located at the corresponding expected position 851 in the imaging device 850 (as if the plurality of detector elements 811 were imaged), then each of the plurality of detector elements 811 is aligned with a corresponding emitter channel among the plurality of emitter channels 822. The corresponding expected position 851 may be determined based on the image 852 of the light-forming marker 812 because the relationship between the marker 812 and the detector element 811 is known and because the optical path configuration is also known (e.g., the focal lengths of the optical devices 823 and 870). For example, as Figure 8AAs shown, if the expected position 851 overlaps with the image 853 (e.g., each image 853 is at the position 851 within a threshold distance), the emitter channel and the detector element are considered to be aligned. If the image 853 deviates from the expected position 851 by more than the threshold distance, the emitter channel and the corresponding detector element are misaligned. In some embodiments, it is also determined whether the image 852 of the light-forming mark 812 is a focused image. When the sharpness of the image 852 is greater than the threshold, it is determined that the image 852 is a focused image. If the image 852 is not a focused image, and / or if the image 853 deviates from the expected position 851, it indicates that the position of the detector element may need to be adjusted for correct alignment with the emitter channel. In some embodiments, it is also determined whether the image 853 of the transmitted light beam 830 is a focused image with a sharpness greater than the threshold. In some embodiments, if the image 852 of the light-forming mark 812 is a focused image and the image 853 of the transmitted light beam 830 is not focused on the expected position 851, it indicates that the position of the detector element may need to be adjusted for correct alignment with the emitter channel in a direction perpendicular to the imaging device 850. In some embodiments, if both the image 852 and the image 853 are focused images, but the image 853 deviates from the expected position 851, it indicates that the position of the corresponding detector element may need to be adjusted for correct alignment with the emitter channel in a direction parallel to the imaging device 850. After adjusting the position of the detector element, this process can be repeated to re-evaluate the alignment. This process can be repeated multiple times until the transceiver is correctly aligned. Therefore, including the light-forming mark in the detector package enables transceiver alignment in the LiDAR system and improves the light collection efficiency. Further, by using the light-forming mark 812 and the imaging device 850 to facilitate the alignment of multiple detector elements 811 with multiple emitter channels 822, the production process of the LiDAR system can be improved, thus saving time and enabling efficient mass production.

[0111] Figure 8B Another example of transceiver alignment in a LiDAR system is illustrated. Similar to Figure 8A , Figure 8B the transceiver 820 further includes two light-forming marks 814a and 814b (collectively referred to as the light-forming mark 814) mounted to the detector package 810. As Figure 8B shown, the light-forming mark 814 includes a rectangular mark. In some embodiments, the light-forming mark 814 includes a mark having one or more designs, and the one or more designs include a linear design, a rectangular design, a circular design, an oval design, a polygonal design, a barcode design, a QR code design, and any free-form shape design. In some embodiments, the light-forming mark 814 is a passive optical mark that does not emit light by itself. Such light-forming marks include at least one of a light-reflecting mark or a light-scattering mark. As Figure 8BAs shown, the light source 862 is configured to emit light 860. The light source 862 is used to provide light to the light-forming markers 814 so that they can reflect or scatter light. In Figure 8B the example shown, one or more optical devices 864 are coupled to the light source 862. One or more optical devices 864 are configured to direct the light 860 emitted by the light source 862 to the light-forming markers 814. In turn, the light-forming markers 814 reflect or scatter the light 860 towards the imaging device 850. Thus, an image 854 of the light-forming markers 814 is formed in the imaging device 850. In Figure 8B the figure, two light-forming markers 814 and corresponding two images 854 are shown, but it should be understood that more or fewer light-forming markers 814 may be included in the detection package 810, and more or fewer images 854 may be correspondingly formed in the imaging device 850. As Figure 8B shown, one or more optical devices 864 include a beam splitter. The beam splitter is configured to reflect the light 860 emitted by the light source 862 to the light-forming markers 814. The beam splitter further transmits most of the light 860 reflected or scattered by the light-forming markers 814 towards the imaging device 850. In some embodiments, when performing the transceiver alignment process, the optical device 823 is used as a collimating lens, which is configured to collimate the light 860 and direct the collimated light 860 towards the imaging device 850. In some embodiments, when the LiDAR system performs scanning under normal operation, the light source 862 is removed from the LiDAR system, and the light-forming markers 814 can be covered or shielded so that they do not reflect / scatter any light. For example, the LiDAR system may include one or more windows (not shown) facing the light-forming markers 814. The windows can be blackened (e.g., after alignment is completed) to prevent the light-forming markers 814 from reflecting or scattering any light to interfere with light detection. Compared with Figure 8A the scenario shown, Figure 8B the embodiment shown uses passive light-forming markers. Therefore, since no electrodes are required to provide electrical signals, more energy can be saved and cost-effectiveness can be improved.

[0112] As Figure 8BAs shown, based on the alignment requirements of the plurality of detector elements 811, the light-forming mark 814 is disposed at a predetermined position relative to the plurality of detector elements 811. The image 853 represents the image formed by the transmitted light beam 830. The geometric relationship between the mark 814 and the detector elements 811 is known. The expected position 851 represents the position of the image detector elements 811 when they are imaged in the imaging device 850. In fact, since the detector elements 811 do not emit any light, they are not imaged. The expected position 851 can be calculated using the position of the image 854 of the light-forming mark 814 and other known data. The known data includes the geometric relationship between the mark 814 and the detector elements 811; and optical path parameters such as the focal lengths of the optical elements 823 and 870. Therefore, based on the image 853 of the transmitted light beam 830 and the image 854 of the light-forming mark 814, it can be determined whether each of the plurality of detector elements 811 is aligned with the corresponding emitter channel in the plurality of emitter channels 822. For example, as Figure 8B shown, if the expected position 851 overlaps with the image 853 (e.g., each image 853 is at the position 851 within a threshold distance), the emitter channel and the detector element are considered to be aligned. If the image 853 deviates from the expected position 851 by more than the threshold distance, the emitter channel and the detector element are not aligned. In some embodiments, it is also determined whether the image 854 of the light-forming mark 814 is a focused image with a sharpness greater than a threshold. If the image 853 is not a focused image, and / or if the image 853 deviates from the expected position 851, it indicates that the position of the detector element may need to be adjusted for correct alignment with the emitter channel. In some embodiments, it is also determined whether the image 853 of the transmitted light beam 830 is a focused image with a sharpness greater than a threshold. In some embodiments, if the image 854 of the light-forming mark 814 is a focused image and the image 853 of the transmitted light beam 830 is not focused on the expected position 851, it indicates that the position of the detector element may need to be adjusted for correct alignment with the emitter channel in a direction perpendicular to the imaging device 850. In some embodiments, if both the image 854 and the image 853 are focused images, but the image 853 deviates from the expected position 851, it indicates that the position of the detector element may need to be adjusted for correct alignment with the emitter channel in a direction parallel to the imaging device 850. After adjusting the position of the detector element, the process can be repeated to re-evaluate the alignment. The process can be repeated multiple times until the transceiver is correctly aligned.

[0113] The light-forming mark thus facilitates transceiver alignment in the LiDAR system and improves the light collection efficiency. Further, by using the light-forming mark 814 and the imaging device 850 to facilitate the alignment of the plurality of detector elements 811 with the plurality of emitter channels 822, this saves time and improves the efficiency of mass production.

[0114] As Figure 8B shown, light source 862 emits light 860 having a wavelength of λm. The light reflected or scattered by the light forming marks 814a and 814b formed by the light also has the same wavelength λm. In some embodiments, the wavelength λm of the light 860 is different from the operating wavelength of the transceiver 820 (i.e., for the wavelength λt of the plurality of transmitted light beams 830, λm≠λt). In order to correctly form images of the light 830 having different wavelengths and the reflected / scattered light from the light 860 on the same imaging device 850, the light forming marks 814 and the plurality of detector elements 811 may have different heights or different distances from the imaging device 850. As Figure 8B shown, the height difference or distance difference between the light forming marks 814 and the plurality of detector elements 811 is shown as their different positions along the h-axis. For example, the mark 814 may be placed closer to the imaging device 850 compared to the detector element 811, and vice versa. Alternatively, the optical devices 823 and / or 870 may be achromatic lenses configured to direct the light 830 and 860 having different wavelengths to appropriately form an image on the same imaging device 850. Despite the different wavelengths, the images formed in this way are still in sharp focus. In some embodiments, the light 860 reflected / scattered by the light forming mark 814 has a wavelength substantially the same as the operating wavelength of the transceiver 820 (i.e., for the wavelength λt of the plurality of transmitted light beams 830, λm = λt). In this case, the light forming mark 814 and the plurality of detector elements 811 may be placed at the same height or the same distance from the imaging device 850. In some embodiments, the light provided by the light forming mark 814a and the light provided by the light forming mark 814b may have different wavelengths. In this case, the light forming marks 814a and 814b reflect or scatter light from different light sources having different wavelengths. In order to correctly form images of the light having different wavelengths on the same imaging device 850, the light forming marks 814a and 814b may have different heights or different distances from the imaging device 850. Additionally or alternatively, the optical devices 823 and / or 870 (such as achromatic lenses) may be used to appropriately form an image in the imaging device 850.

[0115] Figure 8C The figure illustrates alternative ways to address wavelength differences during the transceiver alignment process of a LiDAR system. As Figure 8C shown, a plurality of transmitter channels 822 emit a plurality of transmitted light beams 830. The plurality of transmitted light beams 830 have a wavelength λt, which is the operating wavelength of the transceiver 820. The transceiver 820 further includes a plurality of detector elements 811 and a light forming mark 812 mounted to the detector package 810. As Figure 8CAs shown, the light 840 formed by the light-forming mark 812 (active mark or passive mark) has a wavelength λm that is different from the wavelength λt (i.e., λm≠λt). In some embodiments, the light-forming mark 812 includes a light-emitting device electrically coupled to an electrode (e.g., the electrode 813 shown in Figure 8A ). The electrode is configured to provide electrical signals that cause the light-emitting device to emit the light 840. In some embodiments, the light-forming mark 812 includes a light-reflecting mark or a light-scattering mark. The light-forming mark 812 reflects or scatters the light 840 emitted from a light source (e.g., the light source 862 shown in Figure 8B ).

[0116] As Figure 8C shown, the transmitted beam 830 and the light 840 formed by the light-forming mark 812 are separated by a wavelength-based beam splitter 880. The wavelength-based beam splitter 880 can be, for example, a dielectric beam splitter with wavelength-dependent reflectivity, a beam splitter with wavelength-dependent geometric beam splitting, a fiber optic coupler with wavelength-dependent beam splitting ratio, etc. The separated lights with different wavelengths are respectively guided to separate imaging devices 850a and 850b. Thus, an image 853 of the multiple transmitted beams 830 is formed in the imaging device 850a. An image 852 of the light-forming mark 812 is formed in the imaging device 850b. Figure 8C The figure illustrates that lights with two different wavelengths are respectively guided to two different imaging devices. Images are respectively formed in the two imaging devices. It should be understood that if the light has three or more different wavelengths, correspondingly, the light can be respectively guided to three or more imaging devices, and images can be respectively formed in three or more separate imaging devices.

[0117] Based on the alignment requirements of the multiple detector elements 811, the light-forming mark 812 is located at a predetermined position relative to the multiple detector elements 811. The predetermined position of the light-forming mark 812 is configured to facilitate the alignment of each detector element in the multiple detector elements 811 with the corresponding emitter channel in the multiple emitter channels 822. Based on the image 853 of the transmitted beam 830 formed in the imaging device 850a and the image 852 of the light-forming mark 812 formed in the imaging device 850b, each detector element in the multiple detector elements 811 can be aligned with the corresponding emitter channel in the multiple emitter channels 822. As Figure 8CAs shown, if the image 853 of the transmitted light beam 830 is located at the corresponding expected position 851 in the imaging device 850a (as if the multiple detector elements 811 were imaged), then each detector element among the multiple detector elements 811 is aligned with the corresponding emitter channel among the multiple emitter channels 822. Since the relationship between the marker 812 and the detector element 811 is known, and since the optical path configuration is also known (e.g., the focal length of the optical device 823), the corresponding expected position 851 on the imaging device 850a can be determined. The positions of the imaging devices 850a and 850b are calibrated, and the displacement data between the imaging devices 850a and 850b is also known. Therefore, the corresponding expected position 851 on the imaging device 850a is determined based on the position of the image 852 on the imaging device 850b and the displacement data between the imaging devices 850a and 850b. For example, as Figure 8C shown, if the expected position 851 overlaps with the image 853 (e.g., each image 853 is at the position 851 within a threshold distance), then the emitter channel and the detector element are considered to be aligned. If the image 853 deviates from the expected position 851 by more than the threshold distance, then the emitter channel and the detector element are not aligned. In some embodiments, it is also determined whether the image 852 of the light-forming marker 812 is a focused image with a sharpness greater than a threshold. If the image 852 and / or the image 853 are not focused images on the corresponding imaging devices 850a and 850b, and / or if the image 853 deviates from the expected position 851, it indicates that the position of the detector element may need to be adjusted for correct alignment with the emitter channel. After adjusting the position of the detector element, the process can be repeated to re-evaluate the alignment. This process can be repeated multiple times until the transceiver is correctly aligned. Therefore, including the light-forming marker in the detector package enables transceiver alignment in the LiDAR system and improves the light collection efficiency.

[0118] As described above, the light-forming marker can have various different shapes, sizes, orientations, etc. Figures 9A to 9G is a diagram illustrating examples of light-forming markers 900 - 960 according to some embodiments. The light-forming markers 900 - 960 can be used to implement Figure 7A and Figure 7B the light-forming marker 703 shown, Figure 8A and Figure 8C the light-forming marker 812 shown, and Figure 8B the light-forming marker 814 shown. As Figures 9A to 9G shown, the light-forming markers 900 - 960 include markers having one or more designs, and the one or more designs include a linear design (e.g., the light-forming marker 900 shown in Figure 9A ), a rectangular design (e.g., the light-forming marker 910 shown in Figure 9B ), a circular design (e.g.,Figure 9C the light - formed mark 920) shown, an oval design (e.g., Figure 9D the light - formed mark 930) shown, a polygon design (e.g., Figure 9E the light - formed mark 940) shown, a barcode design (e.g., Figure 9F the light - formed mark 950) shown, and a QR - code design (e.g., Figure 9G the light - formed mark 960) shown. In some embodiments, the light - formed mark can be any free - form shape, which is not limited to Figures 9A to 9G the shape shown. Figures 9A to 9G Each of the light - formed marks in the light - formed marks shown has a known or pre - determined size and geometry. They are set at pre - determined positions relative to the detector elements, and thus the geometric relationship between the marks and the detector elements is known. This data can be used to calculate the position of the image when the detector elements are imaged onto the imaging device. Based on the calculation, it can be determined whether the emitter channels are aligned with the detector elements. When they are aligned, the return light formed by the reflected / scattered light beams of each emitter channel can be properly received by the detector elements, thereby improving the detection efficiency. It should be understood that the number and positions of the light - formed marks can be selected as needed. For example, in a LiDAR system, two marks 900 can be used, while in another system, one mark 910 can be used. Different types of light - formed marks can also be mixed. For example, in another LiDAR system, the light - formed mark 910 and the light - formed mark 930 can be used simultaneously.

[0119] Figures 10A to 10I is a diagram illustrating an example of the position of a light - formed mark 1030 relative to a detector element 1020 according to some embodiments. As Figures 10A to 10I shown, each device 1000 - 1008 includes a detector package 1010 and a plurality of detector elements 1020 mounted to the detector package 1010. The plurality of detector elements 1020 are configured to detect return light and can be used to implement Figure 3 the optical receiver and light detector 330 shown, Figure 7A and Figure 7B the detector element 702 shown, Figures 8A to 8C the detector element 811 shown. In some embodiments such as Figures 10A to 10D 、 Figure 10F 、 Figure 10H and Figure 10I shown, the plurality of detector elements 1020 form a one - dimensional array of detector elements. In some embodiments such as Figure 10E and Figure 10GIn some of the illustrated embodiments, a plurality of detector elements 1020 form a two-dimensional array of detector elements. Other arrangements of the detector elements 1020 may also be implemented (e.g., forming a circular, disk-shaped, polygonal, etc.). As Figures 10A to 10I shown, each device 1000 - 1008 further includes one or more light-forming markers 1030 mounted to the detector package 1010. The light-forming markers 1030 may be the same as Figure 7A and Figure 7B the light-forming markers 703 shown, Figure 8A and Figure 8C the light-forming markers 812 shown, Figure 8B the light-forming markers 814 shown. And they may be implemented by the light-forming markers 900 - 960 shown in Figures 9A to 9G . In some embodiments, the detector package 1010 further includes a PCB. The light-forming markers 1030 are disposed on the PCB. As Figures 10A to 10I shown, the light-forming markers 1030 are located at predetermined positions relative to the plurality of detector elements 1020. As described above, the predetermined positions of the light-forming markers 1030 are configured to facilitate alignment of each detector element among the plurality of detector elements 1020 with a corresponding emitter channel among the plurality of emitter channels. Figures 10A to 10I Illustrated shows the light-forming markers 1030 arranged in such a way that the light-forming markers 1030 have a fixed spatial relationship relative to the plurality of detector elements 1020.

[0120] As Figure 10A and Figure 10B shown, at least two of the two light-forming markers 1030 are positioned at two opposite sides of the array formed by the plurality of detector elements 1020 and outside the array. The array formed by the plurality of detector elements 1020 has a lateral direction and a longitudinal direction. In Figure 10A and Figure 10B , the lateral direction of the array is the horizontal direction, and the longitudinal direction is the vertical direction. In some embodiments as shown in Figure 10A , two opposite sides of the array (e.g., the left side and the right side) are along the lateral direction of the array formed by the plurality of detector elements 1020. As Figure 10A shown, the two light-forming markers 1030 are horizontally aligned at opposite sides of the detector element 1020 array. In some embodiments as shown in Figure 10B , two opposite sides of the array (e.g., the top side and the bottom side) are along the longitudinal direction of the array formed by the plurality of detector elements 1020. As Figure 10B shown, the two light-forming markers 1030 are vertically aligned at two opposite sides of the array.

[0121] As Figures 10C to 10EAs shown, at least two of the light - forming markers 1030 are located on the same side of the array formed by the plurality of detector elements 1020, or at the same corner of the detector package 1010. For example, Figure 10C and Figure 10E The embodiments of show the markers 1030 located on the same left side of the array of elements 1020. And Figure 10D The embodiments of show the markers 1030 located on the same bottom side of the element array 1020. In some embodiments, at least two of the light - forming markers 1030 are horizontally or vertically aligned. As Figure 10C and Figure 10D shown, two light - forming markers 1030 are horizontally aligned. As Figure 10E shown, two light - forming markers 1030 are vertically aligned. It should be understood that the markers need not be horizontally or vertically aligned, or aligned at all. They can form any geometric relationship with respect to each other, as long as the relationship is known and can be used to calculate the position of the image when the detector elements are imaged onto the imaging device.

[0122] As Figure 10F and Figure 10G shown, in some embodiments, at least one of the light - forming markers 1030 can be located between two of the plurality of detector elements 1020. As Figure 10G shown, two light - forming markers 1030 are located between two detector elements of the two - dimensional element array 1020. The two markers 1030 can be horizontally aligned.

[0123] As Figure 10H shown, in some embodiments, at least two of the light - forming markers 1030 are positioned parallel to each other. As Figure 10I shown, in some embodiments, at least two of the light - forming markers 1030 are positioned non - parallel to each other. As will be understood by those of ordinary skill in the art, other arrangements of the markers are also possible.

[0124] Figure 11 shows a flowchart of an exemplary method 1100 for transceiver alignment in a LiDAR system according to some embodiments. The LiDAR system includes a transceiver (e.g., Figures 8A to 8C the transceiver 820 shown in). The transceiver includes a plurality of transmitter channels (e.g., Figures 8A to 8C the transmitted beams 830 shown in) configured to emit a plurality of transmitted beams. The transmitter channels include, for example, Figure 3 the transmitter channel 320 shown in and Figures 8A to 8C the transmitter channel 822 shown in. The LiDAR system further includes a controller (e.g., Figure 3The control circuit 350) shown, the controller being configured to control a plurality of transmitter channels. The transceiver further includes a plurality of detector elements (e.g., Figure 3 the optical receiver and photodetector 330 shown in Figure 7A and Figure 7B the detector element 702 shown in Figures 8A to 8C the detector element 811 shown in Figures 10A - 10G and the detector element 1020 shown in Figure 8A and Figure 8B the imaging device 850 shown in Figure 8C and the imaging devices 850a and 850b shown in

[0125] In step 1110 of method 1100, the controller controls a plurality of transmitter channels to emit a plurality of transmitted light beams towards the imaging device.

[0126] In step 1120 of method 1100, the controller causes one or more light-forming markers (e.g., Figure 7A and Figure 7B the light-forming marker 703 shown in Figure 8A and Figure 8C the light-forming marker 812 shown in Figure 8B the light-forming marker 814 shown in Figures 9A to 9G the light-forming markers 900 - 960 shown in Figures 10A to 10G and the light-forming marker 1030 shown in

[0127] to emit light towards the imaging device. The light-forming markers are positioned at pre-determined positions relative to the plurality of detector elements based on the alignment requirements of the plurality of detector elements. For example, depending on the number of detector elements, the shape / size of the detector elements, and the position of the detector elements, the size / shape / number / position of the light-forming markers can be configured accordingly. In some embodiments, the plurality of detector elements includes a one-dimensional array of detector elements. In some embodiments, the plurality of detector elements includes a two-dimensional array of detector elements.

[0128] In some embodiments, one or more light-forming marks are arranged in such a way that the light-forming marks have a fixed spatial relationship with a plurality of detector elements. In some embodiments, at least two of the two light-forming marks are located at two opposite sides of an array formed by the plurality of detector elements and outside the array. In one embodiment, the two opposite sides of the array are along the longitudinal direction of the array formed by the plurality of detector elements. In one embodiment, the two opposite sides of the array are along the transverse direction of the array formed by the plurality of detector elements. In some embodiments, at least two of the light-forming marks are located at the same side of the array formed by the plurality of detector elements, or at the same corner of the detector package. The plurality of detector elements and one or more light-forming marks are mounted to the detector package. In some embodiments, at least one of the light-forming marks is located between two of the plurality of detector elements. In some embodiments, at least two of the light-forming marks are horizontally or vertically aligned. In some embodiments, at least two of the light-forming marks are parallel to each other. In some embodiments, at least two of the light-forming marks are not parallel to each other.

[0129] In some embodiments, the light formed by one or more light-forming marks has a wavelength that is substantially the same as the operating wavelength of the transceiver. In some embodiments, one or more light-forming marks have the same height as the plurality of detector elements. In some embodiments, the light formed by one or more light-forming marks has a wavelength that is different from the operating wavelength of the transceiver. In one embodiment, the light having a wavelength different from the operating wavelength is separated by a wavelength-based beam splitter and directed to a separate imaging device. In one embodiment, one or more light-forming marks have a height that is different from the height of the plurality of detector elements. In some embodiments, the light formed by at least two of the light-forming marks has different wavelengths. At least two of the light-forming marks have different heights.

[0130] In step 1130 of method 1100, the imaging device forms an image of a plurality of transmitted light beams and an image of one or more light-forming marks.

[0131] In step 1140 of method 1100, the controller aligns the plurality of emitter channels relative to the plurality of detector elements based on the image of the transmitted light beam and the image of one or more light-forming markers. Based on the alignment requirements of the plurality of detector elements, the one or more light-forming markers are positioned at predetermined positions relative to the plurality of detector elements. Thus, the geometric relationship between the markers and the detector elements is known. The expected position of the image of the detector elements can be calculated using the position of the image of the light-forming markers and the known geometric relationship between the markers and the detector elements (as if they were imaged in the imaging device). Thus, based on the image of the transmitted light beam and the image of the light-forming markers, it can be determined whether each of the plurality of detector elements is aligned with the corresponding emitter channel among the plurality of emitter channels. For example, if the expected position overlaps with the image of the transmitted light beam, the emitter channel and the detector element are considered to be aligned. If the image of the transmitted light beam deviates from the expected position by more than a threshold distance, the emitter channel and the detector element are not aligned. After adjusting the position of the detector element, the process can be repeated to re-evaluate the alignment. This process can be repeated multiple times until the transceiver is correctly aligned. By using method 1100 for transceiver alignment, time is saved and the efficiency of mass production is improved.

[0132] Figure 12 An illustrative method 1120 for causing a light-forming marker to emit light according to some embodiments is shown. Figure 12 The step 1120 in Figure 11 is the same as the step 1120 in

[0133] In some embodiments, the one or more light-forming markers include active markers, such as at least one light-emitting device electrically coupled to one or more electrodes. In step 1210 of method 1200, the one or more electrodes provide an electrical signal to the at least one light-emitting device. The at least one light-emitting device causes the at least one light-emitting device to emit light toward the imaging device. In some embodiments, the at least one light-emitting device includes one or more of an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), a light-emitting diode (LED), and a photonic-crystal surface-emitting laser (PCSEL).

[0134] In some embodiments, one or more light - forming markers include passive markers, such as at least one light - reflecting marker or light - scattering marker. In step 1220 of method 1200, the controller controls the light source to emit light. In step 1230 of method 1200, one or more optical devices are optically coupled to the light source. The one or more optical devices direct the light emitted by the light source to at least one light - reflecting marker or light - scattering marker. At least one light - reflecting marker in the light - scattering markers reflects or scatters light. In some embodiments, the one or more optical devices include a beam splitter. The beam splitter is configured to reflect the light emitted by the light source to at least one light - reflecting marker or light - scattering marker. The beam splitter further transmits most of the light reflected or scattered by at least one light - reflecting marker or light - scattering marker towards the imaging device.

[0135] Figure 13 An illustrative method 1140 for aligning multiple emitter channels is shown in accordance with some embodiments. Figure 13 The step 1140 in Figure 11 is the same as the step 1140 in

[0136] Based on the image of the transmitted beam and the image of one or more light - forming markers, the controller aligns the multiple emitter channels relative to the multiple detector elements.

[0137] In step 1310 of method 1300, the controller determines whether the image of one or more light - forming markers is at an expected position relative to the image of the transmitted beam.

[0138] In step 1320 of method 1300, the controller determines whether the image of one or more light - forming markers is a focused image.

[0139] In step 1330 of method 1300, based on determining that at least one image in the image of at least one light - forming marker among the one or more light - forming markers is not at the expected position relative to the image of the transmitted beam, or determining that at least one image in the image of at least one light - forming marker among the one or more light - forming markers is not a focused image, or both, the controller adjusts at least one detector element among the multiple detector elements relative to the corresponding emitter channel.

[0140] The foregoing specification should be understood to be illustrative and exemplary in all respects, rather than restrictive, and the scope of the invention disclosed herein is not determined by the specification, but by the claims as interpreted to the full extent permitted by patent law. It should be understood that the embodiments shown and described herein are merely illustrative of the principles of the invention, and those skilled in the art can make various modifications without departing from the scope and spirit of the invention. Without departing from the scope and spirit of the invention, those skilled in the art can implement various other combinations of features.

Claims

1. An apparatus for transceiver alignment in a Light Detection and Ranging (LiDAR) system, the apparatus comprising: A detector package; A plurality of detector elements mounted to the detector package; And One or more light-forming markers mounted to the detector package at predetermined positions relative to the plurality of detector elements, the predetermined positions of the one or more light-forming markers being configured to facilitate alignment of each of the plurality of detector elements with a corresponding emitter channel among a plurality of emitter channels.

2. The device according to claim 1, wherein The plurality of detector elements form a one-dimensional array of detector elements or a two-dimensional array of detector elements.

3. The device according to any one of claims 1 to 2, wherein The one or more light-forming markers include markers having one or more designs, the one or more designs including a linear design, a polygonal design, a circular design, an oval design, a barcode design, and a QR code design.

4. The device according to any one of claims 1 to 3, wherein, The one or more light-forming markers are arranged in such a way that the light-forming markers have a fixed spatial relationship with the plurality of detector elements.

5. The device according to any one of claims 1 to 4, wherein The one or more light-forming markers include rectangular markers.

6. The device according to any one of claims 1 to 5, wherein At least two of the light-forming markers are positioned at two opposite sides of the array formed by the plurality of detector elements and outside the array.

7. The apparatus according to claim 6, wherein, The two opposite sides of the array are along the longitudinal direction of the array formed by the plurality of detector elements.

8. The device according to claim 6, wherein The two opposite sides of the array are along the transverse direction of the array formed by the plurality of detector elements.

9. The device according to any one of claims 1 to 8, wherein At least two of the light-forming markers are positioned at the same side of the array formed by the plurality of detector elements or at the same corner of the detector package.

10. The apparatus according to any one of claims 1 to 9, wherein, At least one of the light-forming markers is positioned between two of the plurality of detector elements.

11. The device according to any one of claims 1 to 10, wherein, At least two of the two light-forming markers are horizontally or vertically aligned.

12. The device according to any one of claims 1 to 11, wherein, At least two of the light-forming markers are parallel to each other.

13. The apparatus according to any one of claims 1 to 12, wherein, At least two of the light-forming markers are not parallel to each other.

14. The apparatus according to any one of claims 1 to 13, wherein, The one or more light-forming markers include at least one light-emitting device electrically coupled to one or more electrodes, the one or more electrodes being configured to provide an electrical signal that causes the at least one light-emitting device to emit light toward an imaging device.

15. The device according to claim 14, wherein, The at least one light-emitting device includes one or more of an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), a light-emitting diode (LED), and a photonic crystal surface-emitting laser (PCSEL).

16. The device according to any one of claims 1 to 15, wherein, The one or more light-forming markers include at least one light-reflecting marker or light-scattering marker.

17. The device according to claim 16, wherein the device further comprises: A light source configured to emit light; And One or more optical devices optically coupled to the light source, the one or more optical devices being configured to direct the light emitted by the light source to the at least one light-reflecting marker or light-scattering marker, wherein the at least one light-reflecting marker or light-scattering marker reflects or scatters the light toward the imaging device.

18. The device according to claim 17, wherein, The one or more optical devices include a beam splitter configured to reflect the light emitted by the light source to the at least one light-reflective or light-scattering marker and transmit a majority of the light reflected or scattered by the at least one light-reflective or light-scattering marker toward the imaging device.

19. The device according to any one of claims 1 to 18, wherein, The light formed by the one or more light-forming markers has a wavelength substantially the same as the operating wavelength of the transceiver.

20. The apparatus according to any one of claims 1 to 19, wherein, The one or more light-forming markers and the plurality of detector elements are placed at the same height or the same distance from the imaging device.

21. The device according to any one of claims 1 to 18, wherein, The light formed by the one or more light-forming markers has a wavelength different from the operating wavelength of the transceiver.

22. The apparatus according to claim 21, wherein, The light having a wavelength different from the operating wavelength is separated by a wavelength-based beam splitter and directed to a separate imaging device.

23. The apparatus according to any one of claims 1 to 18 or 21, wherein The one or more light-forming markers and the plurality of detector elements are placed at different heights or different distances from the imaging device.

24. The device according to any one of claims 1 to 18, wherein, The light formed by at least two of the light-forming markers has different wavelengths.

25. The apparatus according to any one of claims 1 to 18 or 24, wherein, At least two of the light-forming markers are placed at different heights or different distances from the imaging device.

26. A method for transceiver alignment in a light detection and ranging (LiDAR) system, the method comprising: Controlling a plurality of transmitter channels to emit a plurality of transmitted light beams toward an imaging device; Causing one or more light-forming markers to emit light toward the imaging device, wherein the one or more light-forming markers are positioned at predetermined positions relative to the plurality of detector elements based on alignment requirements of the plurality of detector elements; Forming images of the plurality of transmitted light beams and the one or more light-forming markers; And Aligning the plurality of transmitter channels relative to the plurality of detector elements based on the images of the transmitted light beams and the images of the one or more light-forming markers.

27. The method according to claim 26, wherein, The plurality of detector elements includes a one-dimensional array of detector elements or a two-dimensional array of detector elements.

28. The method according to any one of claims 26 to 27, wherein, The one or more light-forming markers include markers having one or more designs, the one or more designs including a linear design, a polygonal design, a circular design, an oval design, a barcode design, and a QR code design.

29. The method according to any one of claims 26 to 28, wherein The one or more light-forming markers are arranged in space such that the light-forming markers have a fixed spatial relationship with the plurality of detector elements.

30. The method according to any one of claims 26 to 29, wherein, The one or more light-forming markers include rectangular markers.

31. The method according to any one of claims 26 to 30, wherein, At least two of the light-forming markers are positioned at two opposite sides of an array formed by the plurality of detector elements and outside the array.

32. The method according to claim 31, wherein, The two opposite sides of the array are along a longitudinal direction of the array formed by the plurality of detector elements.

33. The method according to claim 31, wherein, The two opposite sides of the array are along a transverse direction of the array formed by the plurality of detector elements.

34. The method according to any one of claims 26 to 33, wherein At least two of the light-forming markers are positioned at the same side of an array formed by the plurality of detector elements or at the same corner of the detector package.

35. The method according to any one of claims 26 to 34, wherein, At least one of the light-forming marks is positioned between two of the plurality of detector elements.

36. The method according to any one of claims 26 to 35, wherein, At least two of the light-forming marks are horizontally or vertically aligned.

37. The method according to any one of claims 26 to 36, wherein At least two of the light-forming marks are parallel to each other.

38. The method according to any one of claims 26 to 36, wherein, At least two of the light-forming marks are not parallel to each other.

39. The method according to any one of claims 26 to 38, wherein, The one or more light-forming marks include at least one light-emitting device electrically coupled to one or more electrodes, wherein causing the one or more light-forming marks to emit light toward the imaging device includes: Providing an electrical signal to the at least one light-emitting device via the one or more electrodes, the electrical signal causing the at least one light-emitting device to emit light toward the imaging device.

40. The method according to claim 39, wherein, The at least one light-emitting device includes one or more of an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), a light-emitting diode (LED), and a photonic-crystal surface-emitting laser (PCSEL).

41. The method according to any one of claims 26 to 40, wherein, The one or more light-forming marks include at least one light-reflecting mark or light-scattering mark.

42. The method according to claim 41, wherein Causing the one or more light-forming marks to emit light toward the imaging device includes: Controlling a light source to emit light; and Directing the light emitted by the light source to the at least one light-reflecting mark or light-scattering mark by one or more optical devices optically coupled to the light source, wherein the at least one light-reflecting mark in the light-scattering marks reflects or scatters the light toward the imaging device.

43. The method according to claim 42, wherein, The one or more optical devices include a beam splitter configured to reflect the light emitted by the light source to the at least one light-reflecting mark and transmit most of the light reflected or scattered by the at least one light-reflecting mark or light-scattering mark toward the imaging device.

44. The method according to any one of claims 26 to 43, wherein The light formed by the one or more light-forming marks has a wavelength substantially the same as the operating wavelength of the transceiver.

45. The method according to any one of claims 26 to 44, wherein, The one or more light-forming marks and the plurality of detector elements are placed at the same height or the same distance from the imaging device.

46. The method according to any one of claims 26 to 43, wherein, The light formed by the one or more light-forming marks has a wavelength different from the operating wavelength of the transceiver.

47. The method according to claim 46, the method further comprising: Separating the light having the different wavelength from the light having the operating wavelength by a wavelength-based beam splitter; And Directing the separated light to a separate imaging device.

48. The method according to any one of claims 26 to 43 or 46, wherein, The one or more light-forming marks and the plurality of detector elements are placed at different heights or different distances from the imaging device.

49. The method according to any one of claims 26 to 43, wherein, The light formed by at least two of the light-forming marks has different wavelengths.

50. The method according to any one of claims 26 to 43 or 49, wherein, At least two of the light-forming marks are placed at different heights or different distances from the imaging device.

51. The method according to any one of claims 26 to 50, wherein, Aligning the plurality of transmission channels relative to the plurality of detector elements based on the image of the transmitted beam and the image of the one or more light-forming marks includes: Determining whether the image of the one or more light-forming marks is at an expected position relative to the image of the transmitted beam; and Determine whether the image of the one or more light-formed markers is a focused image.

52. The method according to claim 51, the method further comprising: Adjusting at least one of the plurality of detector elements relative to a corresponding emitter channel based on determining that at least one image of the one or more light-formed markers is not located at an expected position of the image relative to the transmitted light beam, or determining that at least one image of the one or more light-formed markers is not a focused image, or both.

53. A light detection and ranging (LiDAR) system, the LiDAR system comprising the apparatus according to any one of claims 1 to 25 or performing the apparatus according to any one of methods 26 to 52.

54. A vehicle comprising a light detection and ranging (LiDAR) system, the LiDAR system comprising the apparatus according to any one of claims 1 to 25 or performing the apparatus according to any one of methods 26 to 52.

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