Preamble pulse based LiDAR system and method

Abstract

A LiDAR (310) system comprising: a radiation source to emit a light pulse toward a region of interest (ROI) (380); a detector to detect a light pulse reflected from the ROI (380); a processor communicatively coupled to the radiation source and the detector to: cause the radiation source to emit a leading light pulse having an energy E P and a pulse width W1 toward the ROI (380); determine whether the detector detects the leading light pulse and whether an object (330) is present in the ROI (380); in response to determining that an object (330) is present in the ROI (380), cause the radiation source to emit a scanning light pulse having an energy E L and a pulse width W2 toward the ROI (380); otherwise, cause the radiation source to emit a scanning light pulse having an energy E H and the pulse width W2 toward the ROI (380).

Description

[0001] Cross-referencing

[0002] This application claims priority to U.S. non-provisional patent application No. 16 / 921,174, filed on July 6, 2020, entitled "Premature Pulse-Based LiDAR Systems and Methods". Technical Field

[0003] This invention relates to light detection and ranging (LiDAR) systems, and more specifically to preamble-based LiDAR systems and methods. Background Technology

[0004] Several computer navigation systems for assisting vehicle navigation and / or control have been proposed and implemented in the prior art. These systems include more basic map-assisted positioning techniques (i.e., using computer systems to assist drivers in navigating routes from origin to destination) as well as more complex techniques, such as computer-assisted and / or driver-controlled autonomous driving systems.

[0005] Some of these systems are commonly referred to as "cruise control" systems. In these systems, a computer system installed in the vehicle maintains the speed set by the user. Some cruise control systems implement "intelligent distance control," allowing the user to set a distance to potentially present vehicles ahead (e.g., selecting a value expressed in terms of the number of vehicles), and the computer system adjusts the vehicle speed, at least in part, based on the number of vehicles approaching the potentially present vehicle ahead within the predetermined distance. Some cruise control systems also include a collision control system, which slows or stops the vehicle when it detects a vehicle (or other obstacle) in front of it.

[0006] More advanced systems, such as Advanced Driver Assistance Systems (ADAS), have garnered significant attention in the automotive industry alongside the development of semi-autonomous and / or fully autonomous vehicles. These vehicles can operate with minimal or even no direct operator (i.e., driver) control. These autonomous vehicles include systems capable of accelerating, decelerating, stopping, changing lanes, and parking automatically.

[0007] One of the main technical challenges in implementing the above system is detecting objects located around the vehicle. In one example, the system may need to be able to detect vehicles in front of the current vehicle (the vehicle on which the system is installed), which may pose a risk / hazard to the current vehicle and may require the system to take corrective action, whether it is to slow down or otherwise change speed, stop, or change lanes.

[0008] Typically, ADAS uses a suite of sensors to detect and classify different objects located within a defined region of interest (ROI). One type of sensor used in ADAS is the light detection and ranging (LiDAR) sensor. In a LiDAR-based system, objects around the vehicle are detected by emitting light pulses toward the ROI and measuring the reflected light pulses using a detector. Lasers that emit light pulses within a narrow wavelength range are typically used as the light source. The position and distance of objects can be calculated using the time-of-flight (TOF) calculations of the emitted and detected light pulses. By calculating positions such as "data points," a digital, multi-dimensional representation of the surrounding environment can be generated.

[0009] It can be well established that the power of the reflected light pulse is inversely proportional to the square of the distance the light pulse travels. Furthermore, the power associated with the light pulses generated and emitted by a LiDAR-based system must meet an admissible exposure limit (AEL). Specifically, the AEL limits the power of the laser pulse to ensure eye safety. Therefore, the AEL is a complex function of wavelength, repetition rate, and energy per pulse. This makes detecting long-distance objects difficult due to the low signal-to-noise ratio (SNR). While increasing the emitted pulse power improves the SNR, the emitted pulse power is limited by the AEL for eye safety.

[0010] That said, there is still interest in developing LiDAR-based systems that offer both high SNR and eye safety.

[0011] Several methods and systems are typically used to determine the distance to an object from a LiDAR system. For example, US 20180088214 A1, published March 29, 2018 and now assigned to Okeeffe James Thomas, describes a laser rangefinder that generates a high-intensity laser pulse with an intensity greater than a threshold intensity (e.g., greater than eye-safe intensity) within an adaptive intensity region of the field of view (FOV). The laser rangefinder also generates a low-intensity (e.g., eye-safe) laser pulse within a protected zone (e.g., a protective ring) surrounding the high-intensity laser pulse. This protected zone is located within the FOV such that an entry path to the adaptive intensity region must first pass through the low-intensity protected zone. The laser rangefinder analyzes laser reflections from the protected zone to improve the timely prediction of object intrusion into the adaptive intensity region, thus providing time to determine the object's trajectory or object classification. When it is determined that an object is likely to intersect with the high-intensity laser pulse, the laser rangefinder can stop the high-intensity laser pulse and instead generate a laser pulse with an intensity less than a threshold intensity (e.g., an eye-safe intensity laser pulse).

[0012] US Patent 8948591 B2, published on February 3, 2015, and currently transferred to AIRBUS DS ELECTRONICS AND BORDERSECURITY GMBH in Germany, describes a method for operating a pulse jamming laser in an eye-safe manner within a DIRCM system on an aircraft. A receiving device is used to receive echoes of pulses emitted by the jamming laser and to estimate these echoes to determine whether an object is within the laser beam at a laser safety distance defined by the DIRCM system. During the use of the jamming laser, laser beam emission is activated within a corresponding time period Δt, and emission is activated only for a subsequent time period Δt if no object is detected within the laser safety distance in the preceding time period Δt.

[0013] US9121703B1, published on September 1, 2015 and now assigned to WAYMO LLC, California, describes exemplary methods and systems for controlling the operation of a laser device. One method may include: receiving the output of a proximity sensor located near the laser device; determining, based on the output of the proximity sensor, that an object is within a threshold distance to the laser device. The method may further include: based on the laser device emitting laser pulses, a computing device instructs the laser device to stop emitting laser pulses based on the object being within the threshold distance. The method may further include: based on the laser device being inactive, the computing device instructs the laser device to avoid emitting laser pulses based on the object being within the threshold distance. Summary of the Invention

[0014] According to a first broad aspect of the present invention, a LiDAR system is provided. The LiDAR system includes: a radiation source for emitting light pulses toward a region of interest (ROI); a detector for detecting light pulses reflected from the ROI; and a processor communicatively coupled to the radiation source and the detector, configured to: cause the radiation source to emit light pulses toward the ROI having energy E P A lead-light pulse with pulse width W1 is generated; it is determined whether the detector detects the lead-light pulse and whether an object exists in the ROI; in response to determining that an object exists in the ROI, the radiation source emits a radiation source with energy E toward the ROI. L A scanning light pulse with a pulse width W2; in response to determining that no object exists in the ROI, the radiation source emits a light pulse with energy E toward the ROI. H And the scanning light pulse with the pulse width W2.

[0015] According to the LiDAR system of any other or any of the foregoing aspects of the present invention, the energy E p Less than the energy E L The energy E L Less than the energy E H The energy E H Less than or equal to the peak acceptable exposure limit (AEL) 每脉冲峰值 ).

[0016] According to the LiDAR system of any other or any of the foregoing aspects of the present invention, the energy E L = Standard Acceptable Exposure Limit (AEL) 标准平均值 –E P .

[0017] According to the LiDAR system of any other or any of the foregoing aspects of the present invention, the energy E H =MINIMUM (New Acceptable Exposure Limit (AEL)) 新平均值 Peak acceptable exposure limit (AEL) 每脉冲峰值 )).

[0018] In the LiDAR system according to other or any of the above aspects of the present invention, the pulse width W1 is smaller than the pulse width W2.

[0019] In a LiDAR system according to any other or any of the foregoing aspects of the present invention, the processor waits for a predetermined duration to determine whether the detector has detected the lead light pulse, the predetermined duration being calculated based on an optimal lead distance.

[0020] According to the LiDAR system of any other or any of the foregoing aspects of the present invention, the optimal preamble distance is based on the acceptable exposure limit (AEL) of the peak value of the light pulse. 每脉冲峰值 The width W2 and repetition frequency f are calculated.

[0021] According to other or any of the above aspects of the invention, the LiDAR system further includes: omitting the preleading light pulse received after the predetermined duration.

[0022] According to the LiDAR system of any other or any of the foregoing aspects of the present invention, the energy E P It is calculated based on the minimum estimated signal-to-noise ratio (SNR).

[0023] In the LiDAR system according to any other or any of the foregoing aspects of the invention, the minimum SNR is estimated by a Neyman Pearson detector.

[0024] According to a second, broader aspect of the invention, a LiDAR method is provided. The LiDAR method includes: a radiation source emitting a light pulse toward a region of interest (ROI); a detector detecting a light pulse reflected from the ROI; and a processor communicatively coupled to the radiation source causing the radiation source to emit a light pulse toward the ROI with energy E. P A pre-leading light pulse with pulse width W1; the processor, communicatively coupled to the detector, determines whether the detector detects the pre-leading light pulse and whether an object exists in the ROI; in response to determining that an object exists in the ROI, the processor causes the radiation source to emit a radiation source with energy E toward the ROI. L A scanning light pulse with a pulse width W2; in response to determining that no object exists in the ROI, the processor causes the radiation source to emit a radiation pulse with energy E toward the ROI. H And the scanning light pulse with the pulse width W2.

[0025] According to the LiDAR method of any other or any of the foregoing aspects of the present invention, the energy E p Less than the energy E L The energy E L Less than the energy E H The energy E H Less than or equal to the peak acceptable exposure limit (AEL) 每脉冲峰值 ).

[0026] According to the LiDAR method of any other or any of the foregoing aspects of the present invention, the energy E L = Standard Acceptable Exposure Limit (AEL)标准平均值 –E P .

[0027] According to the LiDAR method of any other or any of the foregoing aspects of the present invention, the energy E H =MINIMUM (New Acceptable Exposure Limit (AEL)) 新平均值 Peak acceptable exposure limit (AEL) 每脉冲峰值 )).

[0028] In the LiDAR method according to any other or any of the above aspects of the present invention, the pulse width W1 is smaller than the pulse width W2.

[0029] In the LiDAR method according to any other or any of the foregoing aspects of the present invention, the processor waits for a predetermined duration to determine whether the detector detects the preleading light pulse, the predetermined duration being calculated based on an optimal preleading distance.

[0030] According to the LiDAR method of any other or any of the foregoing aspects of the present invention, the optimal leader distance is based on the acceptable exposure limit (AEL) of the peak value of the light pulse. 每脉冲峰值 The width W2 and repetition frequency f are calculated.

[0031] According to other or any of the above aspects of the invention, the LiDAR method further includes: omitting the preleading light pulse received after the predetermined duration.

[0032] According to the LiDAR method of any other or any of the foregoing aspects of the present invention, the energy E P It is calculated based on the minimum estimated signal-to-noise ratio (SNR).

[0033] According to the LiDAR method of any other or any of the above aspects of the present invention, the minimum SNR is estimated by a Neyman Pearson detector.

[0034] Other and / or alternative features, aspects and advantages of the present invention will become apparent from the following description, the accompanying drawings and the appended claims. Attached Figure Description

[0035] These and other features, aspects, and advantages of the invention will be better understood in conjunction with the following description, the appended claims, and the accompanying drawings, in which:

[0036] Figure 1 This is a high-level functional block diagram of an exemplary computer system provided in various embodiments of the present invention;

[0037] Figure 2A networked computing environment suitable for use with various embodiments of the present invention is shown;

[0038] Figure 3 This is a high-level functional block diagram of an exemplary LiDAR system provided in various embodiments of the present invention;

[0039] Figure 4 An example of a transmit beam including a group of optical pulses provided by various embodiments of the present invention is shown;

[0040] Figure 5 This is a high-level functional block diagram of a LiDAR system that has the minimum distance to the region of interest (ROI) in the surrounding environment, as provided in various embodiments of the present invention.

[0041] Figure 6 The table showing the AELs for Class 1 and Class 1M laser products is presented in the "Australia / New Zealand Standard: Laser Product Safety";

[0042] Figure 7 A summary of the table providing AEL and correction factors from the "Australian / New Zealand Standard: Safety of Laser Products" is shown;

[0043] Figure 8 This is a high-level functional block diagram of a LiDAR system provided in various embodiments of the present invention, which has a distance greater than 12 cm from the region of interest (ROI) in the surrounding environment.

[0044] Figure 9 These are flowcharts illustrating processes relating to methods implemented on a LiDAR system, provided by various embodiments of the present invention;

[0045] Figure 10 Two different scenarios for emitting a preleading optical pulse, provided by various embodiments of the present invention, are illustrated.

[0046] Figure 11 The relationship between the number N of optical pulses received by the aperture and various leader distance values ​​provided in various embodiments of the present invention is illustrated.

[0047] Figure 12 AEL provided by various embodiments of the present invention is shown. 平均值 The relationship between it and various leading distance values;

[0048] Figure 13 The detection probabilities P provided by various embodiments of the present invention are shown. d The relationship between and SNR;

[0049] Figure 14This is a high-level functional block diagram of a LiDAR system provided in various embodiments of the present invention, the LiDAR system being used to transmit a preamble pulse and then transmit a pulse with energy E. L or E H light pulses;

[0050] Figure 15 This is a flowchart illustrating a process involving a method implemented on a LiDAR system, provided by various embodiments of the present invention.

[0051] It should be understood that similar features are identified by similar reference numerals throughout all the drawings and corresponding descriptions. Furthermore, it should be understood that the drawings and the following description are for illustrative purposes only, and this disclosure is not intended to limit the scope of the claims. Detailed Implementation

[0052] Various representative embodiments of the described technology will be described more fully below with reference to the accompanying drawings, in which representative embodiments are illustrated. However, the concepts in this invention can be embodied in many different forms and should not be construed as limited to the representative embodiments set forth herein. Rather, these representative embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for clarity. Throughout the specification, similar numerals refer to similar elements.

[0053] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Therefore, without departing from the teachings of this invention, the first element discussed below may be referred to as the second element. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0054] It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Conversely, when an element is referred to as "directly connected" or "directly coupled" to another element, there are no intermediate elements. Other terms used to describe the relationship between elements (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.) should be interpreted in a similar manner.

[0055] The terminology used herein is for the purpose of describing particular representative embodiments only and is not intended to limit the invention. Unless the context clearly indicates otherwise, the singular forms “a” and “described” as used herein also include the plural forms. It should also be understood that the term “comprising” as used herein is used to indicate the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0056] Furthermore, all statements herein describing the principles, aspects, and implementations of the technology, and specific examples thereof, are intended to cover their structural and functional equivalents, whether they are currently known or will be developed in the future. Therefore, for example, those skilled in the art will understand that any block diagram herein represents a conceptual view of an illustrative circuit embodying the principles of the invention. Similarly, it should be understood that any flowchart, diagrammatic flowchart, state transition diagram, pseudocode, etc., represents various processes that can be substantially represented in a computer-readable medium and thus executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0057] The functionality of the various elements shown in the figure (including any functional blocks labeled "processor") can be provided using dedicated hardware and hardware capable of executing software in association with appropriate software. When provided by a processor, these functions can be provided by a single dedicated processor, a single shared processor, or multiple separate processors, some of which may share resources. In some embodiments of the invention, the processor may be a general-purpose processor such as a central processing unit (CPU) or a dedicated processor such as a digital signal processor (DSP). Furthermore, the explicit use of the term "processor" should not be construed as specifically referring to hardware capable of executing software, and may implicitly include, but is not limited to, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), read-only memory (ROM), random access memory (RAM), and non-volatile memory for storing software. Other conventional and / or custom hardware may also be included.

[0058] A software module, or simply a module implied as software, may be represented herein as a flowchart element or any combination of other elements indicating process steps and / or textual descriptions of performance. Such modules may be executed by hardware, whether explicitly or implicitly indicated. Furthermore, it should be understood that a module may include, for example, but not limited to, computer program logic, computer program instructions, software, stacks, firmware, hardware circuitry, or combinations thereof, providing the required capabilities.

[0059] Based on these fundamental principles, some non-limiting examples will now be considered to illustrate various implementations of various aspects of the present invention.

[0060] First refer to Figure 1 The diagram illustrates a computer system 100 suitable for use with some implementations of the present invention. The computer system 100 includes various hardware components, including one or more single-core or multi-core processors, collectively referred to as processor 110, a solid-state drive 120, and a memory 130 (which may be random access memory or any other type of memory).

[0061] Communication between various components in computer system 100 can be achieved through one or more internal and / or external buses (not shown) (e.g., PCI bus, Universal Serial Bus, IEEE 1394 FireWire bus, SCSI bus, Serial ATA bus, etc.) electronically coupled to various hardware components. According to some embodiments of the invention, solid-state drive 120 stores program instructions suitable for loading into memory 130 and being executed by processor 110 to determine the presence of an object. For example, the program instructions may be part of a vehicle control application executable by processor 110. It should be noted that computer system 100 may include other components (e.g., network communication module, positioning module, etc.), but for simplicity and operability purposes, Figure 1 These components have been omitted.

[0062] Figure 2 A networked computer environment 200 suitable for use with some embodiments of the present invention is shown. The networked computer environment 200 may include electronic devices 210 associated with vehicle 220 and / or associated with a user (not shown, associated with vehicle 220, such as the operator of vehicle 220), and a server 235 communicating with electronic devices 210 via a communication network 240 (such as the Internet).

[0063] The vehicle 220 associated with the electronic device 210 may include any transport vehicle for leisure or other purposes, such as a private car or commercial vehicle, truck, motorcycle, etc. The vehicle 220 may be a user-operated or driverless vehicle. In at least some embodiments of the invention, it is conceivable that the vehicle 220 may be implemented as a self-driving car (SDC).

[0064] The implementation of electronic device 210 is not particularly limited, but for example, electronic device 210 can be implemented as a vehicle engine control unit, a vehicle CPU, a vehicle navigation device, a tablet computer, a personal computer built into vehicle 220, etc. Therefore, it should be noted that electronic device 210 may or may not be always associated with vehicle 220. Alternatively or additionally, electronic device 210 can be implemented in a wireless communication device such as a mobile phone (e.g., a smartphone or cordless phone). In some embodiments, electronic device 210 may have a display 270.

[0065] Electronic device 210 may include Figure 1 Some or all of the components in the computer system 100 shown. In some embodiments, electronic device 210 is an onboard computer device and includes a processor 110, a solid-state drive 120, and a memory 130. In other words, electronic device 210 includes hardware and / or software and / or firmware or a combination thereof for processing data (described in detail below).

[0066] In some embodiments of the present invention, the communication network 240 is the Internet. In optional, non-limiting embodiments, the communication network can be implemented as any suitable local area network (LAN), wide area network (WAN), dedicated communication network, etc. It should be understood that the implementation of the communication network is for illustrative purposes only. It should be noted that the implementation of the communication link (not separately numbered) between the electronic device 210 and the communication network 240 may depend on the implementation of the electronic device 210, etc. By way of example and not limitation, in these embodiments of the present invention, where the electronic device 210 is implemented as a wireless communication device such as a smartphone or navigation device, the communication link can be implemented as a wireless communication link. Examples of wireless communication links include, but are not limited to, 3G communication network links, 4G communication network links, etc. The communication network 240 may also use a wireless connection with the server 235.

[0067] In some embodiments of the present invention, server 235 is implemented as a computer server and may include Figure 1The server 235 is a component of the computer system 100. However, the server 235 may also be implemented in any other suitable hardware, software, and / or firmware or a combination thereof. In the non-limiting embodiments described in this invention, the server is a single server. In alternative non-limiting embodiments of the invention (not shown), the functionality of the server 235 may be distributed and may be implemented by multiple servers.

[0068] Furthermore, electronic device 210 can communicate with various sensors and systems used to collect information about the surrounding environment of vehicle 220. For example... Figure 2 As shown, vehicle 220 may be equipped with multiple sensor systems 280. It should be noted that different sensor systems among the multiple sensor systems 280 can be used to collect different types of data about the surrounding environment 250 of vehicle 220.

[0069] In some examples, the multiple sensor systems 280 may include one or more radar-type sensor systems mounted in the vehicle 220 and communicatively coupled to the processor 110. More broadly, the one or more radar-type sensor systems can be used to collect data about various parts of the surrounding environment 250 of the vehicle 220 using radio waves. For example, the one or more radar-type sensor systems can be used to collect radar data about objects that may be present in the surrounding environment 250 of the vehicle 220, which may represent the distance of the object to the radar-type sensor system, the object's orientation, the object's speed, etc.

[0070] It should be noted that the multiple sensor systems 280 may include other types of sensor systems besides those described in detail above, without departing from the scope of the present invention.

[0071] In addition, vehicle 220 may be equipped with one or more Light Detection and Ranging (LiDAR) systems 230 for collecting information about the surrounding environment 250 of vehicle 220. The LiDAR system 230 may supplement, or in some cases replace, multiple sensor systems 280. One of the one or more LiDAR systems 230 may be installed (or retrofitted) into vehicle 220 in various locations and / or in various configurations.

[0072] For example, a LiDAR system 230 can be installed on the upper part of the windshield of vehicle 220. However, as Figure 2As shown, other locations where the LiDAR system 230 can be installed within the scope of this invention include the rear window, side windows, hood, roof, front grille, front bumper, or sides of the vehicle 220. In some cases, the LiDAR system 230 can even be installed in a dedicated housing on the top of the vehicle 220.

[0073] As mentioned above, one or more LiDAR systems 230 can also be installed in various configurations.

[0074] In one embodiment, Figure 2 One of the one or more LiDAR systems 230 shown mounted on the roof of vehicle 220 can be mounted in a rotatable configuration. For example, a LiDAR system 230 rotatably mounted in vehicle 220 may include at least some components that can rotate 360 ​​degrees about a rotation axis of the LiDAR system 230. It should be noted that a rotatably mounted LiDAR system 230 can collect most of the data about the surrounding environment 250 of vehicle 220.

[0075] In another embodiment, one of the one or more LiDAR systems 230 mounted to the side (or front grille, etc.) of vehicle 220 may be mounted in a non-rotatable configuration. For example, the LiDAR system 230 mounted in a non-rotatable configuration to vehicle 220 may include at least some components that are non-rotatable 360 ​​degrees and used to collect data about a predetermined portion of the surrounding environment 250 of vehicle 220.

[0076] Regardless of the specific location and / or configuration, in some embodiments, the LiDAR system 230 can be used to capture data about the surrounding environment 250 of the vehicle 220, which is used to construct a multi-dimensional map of objects in the surrounding environment 250 of the vehicle 220.

[0077] refer to Figure 3 This illustrates a non-limiting example of a LiDAR system 310. It should be noted that one or more LiDAR systems 230 (see [reference]) can also be used. Figure 2 This can be achieved in a similar way to the implementation of the LiDAR system 310.

[0078] In a broad sense, the LiDAR system 310 may include various internal components, such as, but not limited to, a radiation source component 312 (e.g., a light source component), a scanner component 316, a receiver component 318, and a controller component 320. It is conceivable that, in addition to the internal components listed above (not exhaustively), the LiDAR system 310 may also include various sensors (e.g., temperature sensors, moisture sensors, etc.), but for simplicity... Figure 3 These sensors are omitted from the text.

[0079] It is conceivable that, under certain circumstances, one or more internal components of the LiDAR system 310 can... Figure 3 This is implemented within the common housing 340 shown. In other implementations, at least the controller assembly 320 may be located remotely from the common housing 340.

[0080] The radiation source assembly 312 can be communicatively coupled to the controller assembly 320 and can be used to emit radiation, such as a beam of radiation signal. In some embodiments, the radiation source assembly 312 is used to emit light and is referred to herein as the light source assembly 312. The light source assembly 312 may include one or more lasers that emit light having a specific operating wavelength. The operating wavelength of the light source assembly 312 may be in the infrared, visible, and / or ultraviolet portions of the electromagnetic spectrum. For example, the light source assembly 312 may include one or more lasers with operating wavelengths between about 650 nm and 1150 nm. Optionally, the light source assembly 312 may include a laser diode for emitting light with wavelengths between about 800 nm and about 1000 nm, between about 850 nm and about 950 nm, or between about 1300 nm and about 1600 nm. However, it should be noted that the light source assembly 312 may include lasers with different operating wavelengths that do not depart from the scope of the present invention.

[0081] In operation, the light source assembly 312 can generate a light emission beam 322. It is conceivable that the emission beam 322 can have any suitable form, such as a continuous wave or a pulsed beam. Figure 3 As shown, the transmitted beam 322 leaves the LiDAR system 310 and points downwards into the surrounding environment 250.

[0082] Assume that there is a distance of 390 between object 330 and LiDAR system 310. However, it should be noted that the presence of object 330 and the distance 390 are unpredictable. LiDAR system 310 can be used to locate object 330 and / or capture data, wherein the data is used to construct a multi-dimensional map of at least a portion of the surrounding environment 250, and object 330 (and other possible objects) is represented in the surrounding environment 250 as one or more data points.

[0083] Once the receiving beam 322 reaches the object 330, the object 330 can reflect at least a portion of the light from the transmitting beam 322, and some of the reflected beam can return to the LiDAR system 310. Reflection indicates that at least a portion of the beam from the transmitting beam 322 bounces off the object 330. A portion of the beam from the transmitting beam 322 can be absorbed by the object 330. Furthermore, a portion of the beam from the transmitting beam 322 can be scattered or refracted by the object 330.

[0084] exist Figure 3 In the example shown, the reflected beam is represented by the receiving beam 324. The receiving beam 324 may be a portion of the transmitting beam 322, which may be captured by the LiDAR system 310 via the receiver assembly 318. It should be noted that in some cases, the receiving beam 324 may include only a relatively small portion of the light from the transmitting beam 322. It should also be noted that the angle of incidence of the receiving beam 324 relative to the surface of the object 330 may be the same as or different from the angle of reflection of the transmitting beam 322 relative to the surface of the object 330.

[0085] It should also be noted that the operating wavelength of the LiDAR system 310 can be within various portions of the electromagnetic spectrum corresponding to sunlight. Therefore, in some cases, direct sunlight can act as background noise, which can mask the light signal detected by the LiDAR system 310. This solar background noise may lead to false positives and / or may otherwise disrupt the measurements of the LiDAR system 310. While it is feasible to improve the signal-to-noise ratio (SNR) of the LiDAR system 310 by increasing the power level of the transmitted beam 322, this is not desirable in at least some cases. For example, increasing the power level of the transmitted beam 322 may make the LiDAR system 310 unsafe for the eyes.

[0086] As described above, the light source assembly 312 may include one or more pulsed lasers for generating, emitting, or radiating optical pulses with a specific pulse duration. For example, the light source assembly 312 may be used to emit pulses with pulse durations (e.g., pulse widths) in the range of 5 ps to 100 ns. Alternatively, the light source assembly 312 may emit pulses at a pulse repetition frequency of approximately 100 kHz to 5 MHz or a pulse period (e.g., the time between consecutive pulses) of approximately 200 ns to 10 μs. However, generally speaking, the light source assembly 312 may generate an emission beam 322 with any suitable average optical power, and the emission beam 322 may include optical pulses with pulse energy or peak optical power suitable for a particular application.

[0087] In some embodiments, the light source assembly 312 may include one or more laser diodes, such as, but not limited to, Fabry-Perot laser diodes, quantum well lasers, distributed Bragg reflector (DBR) lasers, distributed feedback (DFB) lasers, or vertical-cavity surface-emitting lasers (VCSELs). For example, a laser diode operating in the light source assembly 312 may be an aluminum-gallium-arsenide (AlGaAs) laser diode, an indium-gallium-arsenide (InGaAs) laser diode, an indium-gallium-arsenide-phosphide (InGaAsP) laser diode, or any other suitable laser diode. It is also conceivable that the light source assembly 312 may include one or more laser diodes that are current-modulated to generate light pulses.

[0088] It is also conceivable that the emitted beam 322 emitted by the light source assembly 312 may be unpolarized or randomly polarized, may not have a specific or fixed polarization (e.g., the polarization may change over time), or may have a specific polarization (e.g., the emitted beam 322 may be linearly polarized, elliptically polarized, or circularly polarized).

[0089] In at least some embodiments, the transmit beam 322 and the receive beam 324 may be substantially coaxial. In other words, the transmit beam 322 and the receive beam 324 may at least partially overlap or share a common propagation axis, such that the receive beam 324 and the transmit beam 322 propagate along substantially the same optical path (but in opposite directions). However, in other embodiments, it is conceivable that the transmit beam 322 and the receive beam 324 may not be coaxial, or in other words, they may not overlap or share a common propagation axis within the LiDAR system 310, without departing from the scope of the invention.

[0090] It should be noted that, in at least some embodiments of the present invention, when the LiDAR system 310 is implemented in a rotatable configuration, the light source assembly 312 can rotate about the rotation axis (not shown) of the LiDAR system 310, for example, by 360 degrees or less. However, in other embodiments, even if the LiDAR system 310 is implemented in a rotatable configuration, the light source assembly 312 may be stationary, without departing from the scope of the present invention.

[0091] like Figure 3As shown, the LiDAR system 310 can use one of multiple internal beam paths 314 to transmit a transmitted beam 322 (generated by the light source assembly 312) to the surrounding environment 250. In one example, one of the multiple internal beam paths 314 can provide light from the light source assembly 312 to the scanner assembly 316, which can then direct the transmitted beam 322 downwards towards the surrounding environment 250.

[0092] Furthermore, the LiDAR system 310 can utilize another internal beam path among the multiple internal beam paths 314 to provide the receiving beam 324 to the receiver assembly 318. In one example, another internal beam path among the multiple internal beam paths 314 can provide the receiving beam 324 from the scanner assembly 316 to the receiver assembly 318. In another example, another internal beam path among the multiple internal beam paths 314 can provide the receiving beam 324 directly from the surrounding environment 250 to the receiver assembly 318 (the receiving beam 324 does not pass through the scanner assembly 316).

[0093] It should be noted that the multiple internal beam paths 314 may include various optical components. For example, the LiDAR system 310 may include one or more optical components for adjusting, shaping, filtering, modifying, controlling, or guiding the transmit beam 322 and / or the receive beam 324. For example, the LiDAR system 310 may include one or more lenses, mirrors, filters (e.g., bandpass or interference filters), optical fibers, circulators, beam splitters, polarizers, polarization beam splitters, waveplates (e.g., half-wave or quarter-wave plates), diffraction elements, microelectromechanical (MEMS) components, collimating elements, or holographic elements.

[0094] It is conceivable that, in at least some embodiments, one of the multiple internal beam paths 314 and another internal beam path may share at least some common optical components; however, this may not be the case in each embodiment of the invention.

[0095] Typically, the scanner assembly 316 directs the emitted beam 322 downwards toward the surrounding environment 250 in one or more directions. The scanner assembly 316 may include various optical and / or mechanical components for scanning the emitted beam 322. For example, the scanner assembly 316 may include one or more mirrors, prisms, lenses, MEMS components, piezoelectric components, optical fibers, splitters, diffraction elements, collimating elements, etc. It should be noted that the scanner assembly 316 may also include one or more actuators (not shown) that drive at least some optical components to rotate, tilt, pivot, or move at an angle about one or more axes.

[0096] The scanner component 316 can be used to scan the emitted beam 322 within a variety of horizontal and / or vertical angular ranges. In other words, the scanner component 316 can help provide the LiDAR system 310 with a desired Region of Interest (ROI) 380. The ROI 380 of the LiDAR system 310 can refer to the area, volume, region, angular range, and / or one or more portions of the surrounding environment 250 that the LiDAR system 310 can use to scan and / or capture data.

[0097] It should be noted that the scanner component 316 can be used to scan the transmitted beam 322 horizontally and / or vertically; therefore, the ROI 380 of the LiDAR system 310 can have both horizontal and vertical orientations. For example, the LiDAR system 310 can have a 360-degree horizontal ROI and a 45-degree vertical ROI.

[0098] Scanner component 316 may be communicatively coupled to controller component 320. Therefore, controller component 320 may be used to control scanner component 316 to point the transmit beam 322 downwards in a desired direction and / or follow a desired scanning pattern. Broadly speaking, scanning pattern can refer to the mode or path by which the transmit beam 322 is guided by scanner component 316 during operation.

[0099] Therefore, the LiDAR system 310 can utilize the scanning mode to generate a point cloud that substantially covers the ROI 380 of the LiDAR system 310. The point cloud of the LiDAR system 310 can be used to present a multi-dimensional map of objects in the surrounding environment 250 of the vehicle 220.

[0100] In operation, in some embodiments, the light source assembly 312 emits light pulses (represented by the emitted beam 322), and the scanner assembly 316 scans the light pulses within the ROI 380 of the LiDAR system 310 according to a scanning mode. As described above, the object 330 may reflect one or more emitted pulses. The receiver assembly 318 receives or detects photons from the receive beam 324 and generates one or more representative data signals. For example, the receiver assembly 318 may generate an output electrical signal representing the receive beam 324. The receiver assembly 318 may also provide the generated electrical signal to the controller assembly 320 for further processing.

[0101] Receiver assembly 318 is communicatively coupled to controller assembly 320 and can be implemented in various ways. For example, receiver assembly 318 may include a photoreceiver, optical receiver, optical sensor, detector, photodetector, optical detector, optical fiber, etc. As described above, in some embodiments, receiver assembly 318 acquires or detects at least a portion of receive beam 324 and generates an electrical signal corresponding to receive beam 324. For example, if receive beam 324 includes optical pulses, receiver assembly 318 may generate a current or voltage pulse corresponding to the optical pulse detected by receiver assembly.

[0102] It is conceivable that the receiver component 318 can be implemented using one or more avalanche photodiodes (APDs), one or more single-photon avalanche diodes (SPADs), one or more PN photodiodes (e.g., photodiode structures composed of p-type and n-type semiconductors), one or more PIN photodiodes (e.g., photodiode structures composed of undoped semiconductor regions located between p-type and n-type regions), etc.

[0103] In some non-limiting embodiments, receiver assembly 318 may further include circuitry for performing signal amplification, sampling, filtering, signal conditioning, analog-to-digital conversion, time-to-digital conversion, pulse detection, threshold detection, rising edge detection, falling edge detection, etc. For example, receiver assembly 318 may include electronic components for converting received photocurrent (e.g., current generated by the APD in response to the received optical signal) into a voltage signal. Receiver assembly 318 may also include additional circuitry for generating an analog or digital output signal corresponding to one or more characteristics of the received optical pulse (e.g., rising edge, falling edge, amplitude, duration, etc.).

[0104] According to the implementation, controller component 320 may include one or more processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and / or other suitable circuitry. Controller component 320 may also include non-transitory computer-readable memory for storing instructions executable by controller component 320, as well as data generated by controller component 320 based on signals acquired from other internal components of LiDAR system 310 and / or data provided based on signals sent to other internal components in LiDAR system 310. The memory may include volatile (e.g., RAM) and / or non-volatile (e.g., flash memory, hard disk) components. Controller component 320 can be used to generate data during operation and store the data in memory. For example, data generated by controller component 320 may represent data points in the point cloud of LiDAR system 310.

[0105] It is conceivable that, in at least some non-limiting embodiments of the present invention, the controller component 320 may be implemented in a manner similar to that of the electronic device 210 and / or the computer system 100, without departing from the scope of the present invention.

[0106] In addition to collecting data from receiver component 318, controller component 320 may also provide control signals to light source component 312 and scanner component 316, and may also receive diagnostic data from light source component 312 and scanner component 316.

[0107] As described above, the controller component 320 is communicatively coupled to one or more of the light source component 312, the scanner component 316, and the receiver component 318. The controller component 320 can receive electrical trigger pulses from the light source component 312, wherein each electrical trigger pulse corresponds to a light pulse emission from the light source component 312. The controller component 320 can also provide commands, control signals, and / or trigger signals to the light source component 312, instructing it when to generate a light pulse.

[0108] For example, controller component 320 can be used to send an electrical trigger signal including electrical pulses, causing light source component 312 to emit light pulses in response to each electrical pulse of the electrical trigger signal. It is also conceivable that controller component 320 can cause light source component 312 to adjust one or more characteristics of the light generated by light source component 312, such as, but not limited to, frequency, period, duration, pulse energy, peak power, average power, and wavelength of the light pulse.

[0109] It should be noted that the controller component 320 can be used to determine the "time-of-flight" value of the light pulse based on timing information associated with (i) the time when the light source component 312 emits a pulse and (ii) the time when the receiver component 318 detects or receives a portion of the pulse (e.g., from the receiving beam 324).

[0110] It is conceivable that the controller component 320 can be used to analyze one or more features of the electrical signals from the light source component 312 and / or the receiver component 318 to determine one or more features of the object 330, such as the downward distance 390 from the LiDAR system 310.

[0111] For example, controller component 320 can determine the time-of-flight value and / or phase modulation value of the transmitted pulse of transmitted beam 322. Assuming LiDAR system 310 determines the time-of-flight value "T", it represents, in a sense, the "round-trip" time of the transmitted pulse propagating from LiDAR system 310 to object 330 and back to LiDAR system 310. Therefore, controller component 320 can be used to determine distance 390 according to the following equation:

[0112]

[0113] Where D is the distance 390, T is the time of flight, and c is the speed of light. Although the ideal speed of light in a vacuum is 299,792,458 m / s, the actual speed of light may depend on the refractive index n of the medium through which the light propagates. The relationship between the ideal speed of light in a vacuum and the speed of light in a certain medium is given by the following equation:

[0114]

[0115] Where v is the speed of light in a given medium, and n is the refractive index of the corresponding medium. For example, if the medium is air, the refractive index n is approximately 1.0003, therefore the speed of light is approximately 299,702,547 m / s. Similarly, if the medium is glass, the refractive index n is approximately 1.5, therefore the speed of light is approximately 199,861,638 m / s. It should be noted that, for simplicity, the speed of light in air is assumed to be approximately 3.0 × 10⁸ m / s for various calculations in this invention. However, without limiting the scope of this invention, actual values ​​of the speed of light can be considered for various calculations.

[0116] As described above, the LiDAR system 310 is used to determine the distance to one or more other objects that may be present in the surrounding environment 250. By scanning the emitted beam 322 within the ROI 380 of the LiDAR system 310 according to the scanning pattern, the LiDAR system 310 is used to map the distance (similar to distance 390) to corresponding data points within the ROI 380 of the LiDAR system 310. Therefore, the LiDAR system 310 can be used to present these continuously captured data points (e.g., point clouds) in the form of a multi-dimensional map.

[0117] For example, this multidimensional map is used by electronic device 210 to detect or otherwise identify objects or determine the shape or distance of objects that may exist within the ROI 380 of LiDAR system 310. It is conceivable that LiDAR system 310 can be used to repeatedly / iterately capture and / or generate point clouds at any rate suitable for a particular application.

[0118] It should be noted that the position of an object in the surrounding environment 250 of vehicle 220 can at least partially overlap, surround, or close within the ROI of LiDAR system 310. For example, object 330 may include people, vehicles, motorcycles, trucks, trains, bicycles, wheelchairs, strollers, pedestrians, animals, road signs, traffic lights, lane markings, road markings, parking spaces, cable towers, guardrails, traffic barriers, potholes, railway crossings, obstacles on or near roads, curbs, vehicles parked on or by the roadside, utility poles, houses, buildings, trash cans, mailboxes, trees, any other suitable objects, or all or part of any suitable combination of all or part of two or more objects.

[0119] By placing these non-limiting embodiments of the LiDAR system 310 in their proper places, we will now consider some specific examples to illustrate various implementations of various aspects of the invention.

[0120] As mentioned above (in) Figure 3 In the LiDAR system 310, the receiving beam 324 can be part of the transmitting beam 322, which can be captured by the receiving system 310 via the receiver assembly 318. Furthermore, the receiving beam 324 can be subject to various noises, thus attenuating the SNR. Additionally, the power P associated with the receiving beam 324 is generally... rx (t) is inversely proportional to the distance D, where D represents the distance 390 from the LiDAR system 310 to the object 330. This relationship further leads to a significant decrease in SNR because the object is farther away from the LiDAR system 310. Furthermore, the power P associated with the received beam 324... rx (t) and the power P associated with the transmitted beam 322 tx(t) is linearly proportional. This can be expressed mathematically as:

[0121]

[0122] It is clear from equation (3) that increasing the power P associated with the transmitted beam 322... tx (t) will significantly improve SNR. Since light with wavelengths in the 600nm–1000nm range can be focused and absorbed by the eye, the maximum power P associated with the emitted beam 322 is... tx (t) Subject to eye safety regulations, such as those defined in the Australian / New Zealand Standard: Safety of Laser Products.

[0123] In this invention, embodiments of the invention will be described with reference to the nomenclature of “Australia / New Zealand Standard: Safety of Laser Products”, but it should be understood that the invention also applies to subsequent versions and corresponding versions of this standard.

[0124] The Australian / New Zealand Standard for Laser Product Safety defines the Maximum Permissible Exposure (MPE) and the Accessible Emission Limit (AEL). MPE is the maximum level of light radiation a person can be exposed to before suffering direct or long-term injury. This maximum permissible exposure is determined based on the energy density limits that the cornea and skin can withstand, or the limits per unit power (intensity) per surface area. MPE is calculated as a function of the radiation wavelength, pulse duration, duration of exposure to the exposed tissue (skin or eye), and image size on the retina. While MPE defines the maximum pulse energy in terms of injury risk, AEL is derived from the wavelength, power, and energy of the radiation emitted by the laser and can be accessed by a user (e.g., the human eye) at a specified distance of 390 from the LiDAR system 310.

[0125] These definitions are used by eye safety regulations because they represent the method of approaching the LiDAR system 310 as closely as possible using the human eye or an observation instrument such as a telescope. Using the definitions in the "Australian / New Zealand Standard: Safety of Laser Products," an aperture of 395 (detailed below) can be defined as a circular area with a diameter of 7 mm at a distance of 12 cm from the LiDAR system 310. Therefore, the AEL can classify lasers based on the associated radiation damage, depending on the performance specifications of each laser.

[0126] As described above, the transmitted beam 322 may include optical pulses. Figure 4An example of a transmit beam 322 including a group of optical pulses provided by various embodiments of the present invention is shown. As shown, in a non-limiting embodiment, the transmit beam 322 may include groups of optical pulses, such as optical pulse groups 322-1, 322-2...322-n. The number of optical pulses in each optical pulse group 322-1, 322-2...322-n, as well as the power level and width w of each optical pulse, can be selected to reliably detect the reflected beam 322 by the receiver assembly 318. Furthermore, in some embodiments, two optical pulses in a pulse group may be spaced apart by an angular displacement. For example, two optical pulses in optical pulse group 322-1 may be spaced apart by an angular distance of 0.1° (horizontal and / or vertical angular resolution).

[0127] In some non-limiting embodiments, the time difference t between two optical pulses in optical pulse group 322-1 can be equal to 10 μs. That is, within optical pulse group 322-1, the optical pulses can have a repetition rate f of 100 kHz. Furthermore, in one embodiment, the optical pulses can have a wavelength of 905 nanometers (nm), and each pulse can have a width of 5 nanometers (ns). It should be noted that the above specifications for optical pulses and optical pulse groups are merely examples, and any other suitable specifications can be used without limiting the scope of the invention. It should be understood that although the above specifications have been detailed in conjunction with optical pulse group 322-1, the same specifications also apply to each optical pulse group 322-2…322-n.

[0128] According to the "Australian / New Zealand Standard: Laser Product Safety", the total energy / function of the light pulses in group 322-1 of light pulses received by the human eye near LiDAR system 310 when scanning an object can be determined according to AEL. 总能量 Sure.

[0129] Considering the repetition rate of the optical pulse is f, and the number of optical pulses in optical pulse group 322-1 is N, the AEL is calculated according to the requirements specified in "Australian / New Zealand Standard: Laser Product Safety". 总能量 This allows N optical pulses to be considered as a single pulse with a pulse width of T = N / f. The energy / power of each pulse can be obtained by averaging AEL. 总能量 To estimate:

[0130]

[0131] To ensure that the transmitted beam 322 is safe for the eyes, the AEL expressed by formula (3) is used. 平均值 (also referred to as AEL in this article) 标准平均值The value must be less than the maximum AEL per light pulse according to the requirements of "Australia / New Zealand Standard: Laser Product Safety". 每脉冲能量 (also referred to as AEL in this article) 每脉冲峰值 ).

[0132] Figure 5 This is a high-level functional block diagram of a LiDAR system 310 provided in various embodiments of the present invention, which maintains a minimum distance 390 from an Area of ​​Interest (ROI) 380 in the surrounding environment 250. As shown, the emitted beam 322 from the LiDAR system 310 can be directed toward the ROI 380. In some embodiments, a person may be present in the ROI 380. On average, the pupil of a human eye is about 7 mm wide. For the sake of simplicity, the pupil of a human eye is represented as an aperture 395 with a diameter of 7 mm. Since the presence of a person is known a priori, it is assumed that the aperture 395 can be 12 cm away from the LiDAR system 310.

[0133] To calculate the number of light pulses that aperture 395 can receive when the emitted beam 322 from LiDAR system 310 is directed toward ROI 380, the exposure angle α is calculated as follows:

[0134]

[0135] Assuming an angular resolution of 0.1° (as described above), the number N of optical pulses received by an aperture of 395 can be calculated as follows: One light pulse. Since the repetition rate f is assumed to be 100 kHz, the relationship T = N / f will be used to calculate AEL. 总能量 The total emission duration of the 33 optical pulses was determined to be 33 optical pulses / 100kHz = 330μs.

[0136] Figure 6 Table 400, from the "Australia / New Zealand Standard: Laser Product Safety," provides the AEL (Advanced Level Emissions) for Class 1 and Class 1M laser products. For a given emission duration and associated wavelength, the AEL can be calculated using Table 400. 总能量 .

[0137] Figure 7 The abstracts of Table 400-1 and another abstract of Table 402, which provides correction factors in “Australia / New Zealand Standard: Safety of Laser Products,” are shown. As described above, with the total emission duration of 33 optical pulses calculated as 330 μs and the relevant wavelength calculated as 905 nm, the AEL value in Abstract Table 400-1 can be used to determine the AEL. 总能量 Calculated as 7×10 - 4 t 0.75C4 joules, where C4 is calculated as C4 = 10 using the correction factor provided in abstract table 402. 0.002(λ-700) AEL 总能量 The result is 4.4 μJ. For 33 optical pulses, according to equation (4), AEL is... 平均值 The calculated value is 133.5 nJ (26.7 W peak power). Furthermore, it is noted from abstract table 400-1 that the peak AEL of a 5 ns wide optical pulse is... 每脉冲峰值 It is 200nJ (40W peak power).

[0138] As mentioned above, for a given angular resolution, the number of light pulses that can be scanned at aperture 395 depends primarily on the exposure angle α. The exposure angle α = 3.3° in Equation (5) is calculated using the minimum distance of 12 cm between aperture 395 and LiDAR system 310, since there is no prior information about the nearest aperture 395 to LiDAR system 310.

[0139] like Figure 8 As shown, objects at a distance greater than 12cm do not result in a smaller exposure angle α. Since the number of light pulses with a scanning aperture of 395 is proportional to the exposure angle α, the number of light pulses with a scanning distance greater than 12cm with an aperture of 395 will also decrease. Furthermore, AEL... 平均值 The amplitude of the light pulses will also increase as the number of light pulses with the scanning aperture 395 decreases. To this end, light pulses with larger amplitudes (i.e., light pulses with increased energy / power) can be used to cover a larger area, thereby improving the SNR associated with the receiving beam 324 and thus improving the detectability of objects at greater distances.

[0140] Speaking of which, Figure 9 This is a flowchart illustrating a process 500 involving a method implemented on a LiDAR system 310, provided by various embodiments of the present invention.

[0141] As shown in the figure, process 500 begins at step 502. In step 502, the light source assembly 312 generates a preleading light pulse, and the scanner assembly 316 emits the preleading light pulse toward the ROI 380. In some embodiments, the performance characteristics of the preleading light pulse may differ from those of the scanning light pulses emitted by the LiDAR system 310 (e.g., the scanning light pulses included in the light pulse group 322-1). In one example, the preleading light pulse may have a width W of 2 ns and an associated pulse energy E. p =10nJ (i.e., 5W). It should be noted that the above performance indicators of the preleading light pulse are merely a non-limiting example. On the contrary, without limiting the scope of the invention, the preleading light pulse may have any other suitable performance indicators.

[0142] Process 500 proceeds to step 504. In step 504, the controller component 320 waits for a predefined time period and then verifies whether the scanner component 316 has received the emitted prelead light pulse. If the scanner component 316 has received the emitted prelead light pulse, process 500 proceeds to step 506; otherwise, process 500 proceeds to step 508.

[0143] In step 506, the controller component 320 determines that an object exists near the LiDAR system 310 and calculates the distance from the LiDAR system 310 to the object according to equation (1). In some embodiments, the detected object may or may not be a person; in either case, the controller component 320 may also use the distance calculated from the system. Figure 6 and Figure 7 The table shown and equation (4) are used to calculate AEL. 标准平均值 It should be noted that the detected object can be a person. To emit eye-safe pulses, the controller assembly 320 can instruct the light source assembly 312 to generate energy E. L =AEL 标准平均值 -E p The next optical pulse (also referred to as the scan pulse in this paper), where E p This is the energy associated with the emitted preleading optical pulse. Furthermore, the energy E... L This ensures that the transmitted pulse is below the required safety level.

[0144] In step 508, since the scanner component 316 did not receive the emitted preleader light pulse, the controller component 320 determines that there is no object near the LiDAR system 310. That is, there is no person near the LiDAR system 310. Therefore, the controller component 320 can use... Figure 6 and Figure 7 The table shown and equation (4) are used to calculate AEL. 新平均值 The controller component 320 can control AEL. 新平均值 With AEL 每脉冲峰值 The values ​​are compared. Regardless of which value is smaller, the controller component 320 instructs the light source component 312 to generate energy E. H =MIN(AEL) 新平均值 AEL 每脉冲峰值 The next light pulse.

[0145] In this scenario, the LiDAR system 310 can radiate pulses with increased energy levels to further improve the SNR of the LiDAR system 310, thereby enhancing the detectability of objects at greater distances. Furthermore, in some embodiments, if a preleading light pulse is received after a scan pulse, the controller assembly 320 may omit the preleading light pulse used to determine objects in the ROI 380.

[0146] Figure 10 Two different scenarios 602 and 604 for emitting a preleading light pulse, provided by various embodiments of the present invention, are illustrated. As shown in scenario 602, the LiDAR system 310 can emit a preleading light pulse 602 toward an ROI 380. In some embodiments, if the preleading light pulse 604 is reflected from an object 330, the controller assembly 320 determines that an object 330 is present near the LiDAR system 310. Since the detected object may be a person, to ensure eye safety for the LiDAR system, the controller assembly 320 can instruct the light source assembly 312 to generate energy E. L =AEL 标准平均值 -E p The next optical pulse 606 (as described above in process 500).

[0147] In the second scenario 608, the LiDAR system 310 can emit a lead light pulse 602 toward the ROI 380. In some embodiments, the controller assembly 320 can wait for a certain duration to reflect the lead light pulse 604. If the lead light pulse 604 is not reflected, the controller assembly 320 determines that there may be no object in the vicinity of the LiDAR system 310. To further improve the SNR of the LiDAR system 310, the controller assembly 320 makes the LiDAR system eye-safe by instructing the light source assembly 312 to generate energy E. H =MIN(AEL) 新平均值 AEL 每脉冲峰值 The next optical pulse 610 is as described above in process 500. It should be noted that the energy levels of optical pulses 604, 606, and 610 can follow the following order: E P <<E L <E H ≤AEL 每脉冲峰值 .

[0148] It should be noted that the number N of optical pulses received by an aperture of 395 is given by the following equation:

[0149]

[0150] In some embodiments, the horizontal resolution can be equal to 0.1°. Therefore, for various values ​​of the leader distance, i.e. the distance between aperture 395 and LiDAR system 310, the number N of optical pulses received by aperture 395 can be estimated according to equation (6). Figure 11 The relationship between the number N of optical pulses received by the aperture 395 provided in various embodiments of the present invention and various preamble distance values ​​is illustrated. As shown in the figure, the number N of optical pulses received by the aperture 395 decreases as the preamble distance increases.

[0151] Furthermore, according to equation (4), Figure 12 AEL provided by various embodiments of the present invention is shown. 平均值 The relationship between AEL and various leader distance values. As shown in the figure, as the leader distance value increases, AEL... 平均值 This will also increase. In a non-limiting example, as described above, when the optical pulse is 5 ns, the wavelength is 905 nm, and the repetition rate is 100 kHz, the total pulse duration is used. According to Table 400 (e.g.) Figure 6 (As shown) Determine AEL 总能量 , where N is calculated according to equation (6). Although as Figure 12 As shown, the preamble distance varies with different values; however, a light pulse with a pulse width of 5 ns may not exceed the AEL. 每脉冲峰值 =200nJ. Therefore, the optimal lead distance for an optical pulse with a pulse width of 5ns, a wavelength of 905nm, and a repetition rate of 100kHz can be 65cm.

[0152] The optimal preamble distance represents the maximum distance a preamble optical pulse (e.g., 604) will travel before returning to the LiDAR system 310. In some embodiments, the optimal preamble distance can be determined based on AEL. 每脉冲峰值 The pulse width of the scanning pulse and the repetition frequency f of the scanning light pulse are calculated.

[0153] It should be noted that the leader light pulse (e.g., 604) must have sufficient energy to detect an object located at the optimal leader distance. The leader signal energy / power is determined based on the background noise to obtain the minimum SNR with a detection probability of 1 (due to objects at the calculated leader distance returning to the leader).

[0154] The minimum SNR can be estimated using the Neyman Pearson detector:

[0155]

[0156] Among them, P fa This represents the probability of a false alarm (set within a constant range of 10). -4 ~10 -6(between), Q represents the Q function. Figure 13 The detection probabilities P provided by various embodiments of the present invention are shown. d The relationship between SNR and SNR. As shown in the figure, in some embodiments, when the SNR is approximately 17.5 dB, the detection probability P... d It can be equal to 1.

[0157] Figure 14 This is a high-level functional block diagram of a LiDAR system 310 provided in various embodiments of the present invention. The LiDAR system 310 is used to transmit a preamble pulse (e.g., 604) and then transmit a pulse with energy E. L (e.g., 606) or E H (e.g., 610) a light pulse. In some embodiments, the light source assembly 312 can be used to generate a pre-lead light pulse (e.g., 604), and the scanner assembly 316 can be used to emit the pre-lead light pulse (e.g., 604) toward the ROI 380. In some embodiments, the pre-lead light pulse (e.g., 604) can have a pulse width of 2 ns and an E p =10nJ (i.e., 5 watts) to check for the presence of an object at the optimal lead distance (e.g., 65cm). It can be envisioned that in order to pass through the optimal lead distance (e.g., 65cm) and return to the LiDAR system 310, the controller component 320 can calculate the time-of-flight (TOF) according to equation (1).

[0158] In one example, when the optimal leader distance is 65 cm, the Time of Flight (TOF) can be approximately 4.33 ns, which is less than the repetition rate of 10 μs (based on a repetition frequency of 100 kHz). In other words, the LiDAR system 310 can be used to emit light pulses every 10 μs. However, the first pulse can be a leader light pulse (e.g., 604). As mentioned above, the TOF of the leader light pulse (e.g., 604) can depend on the optimal leader distance and can be very less than the repetition rate of the light pulse. Therefore, depending on whether the emitted leader light pulse (e.g., 604) is reflected back to the LiDAR system 310 within a predetermined time period, where the predetermined time period can be based on the optimal leader distance, the light source assembly 312 can be used to adjust the energy / power of the next light pulse to be emitted.

[0159] In some embodiments, this adjustment to the scanning light pulse can be calculated by the controller component 320, and the controller component 320 can provide the required adjustment amount to the light source component 312. For example, in some embodiments, if an object is detected based on the reflected leader light pulse, the controller component 320 can transfer energy E L Calculated as E L =AEL 标准平均值 -E p AEL 标准平均值It can be calculated according to equation (4). It should be noted that AEL... 标准平均值 The value can be based on the following assumptions: aperture 395 can have a diameter of 7 mm and can be 12 cm away from LiDAR system 310. As calculated above, AEL 标准平均值 This can be equal to 133.5 nJ (26.7 W peak power). Therefore, the calculated energy E L It can be equal to E L =133.5-10=123.5nJ (24.7W peak power). The light source assembly 312 can be used to generate energy E. L The next light pulse is 123.5 nJ. Then, the light pulse is emitted to ROI 380.

[0160] In some embodiments, if no object is detected, i.e., the emitted preleading light pulse is not reflected back to the LiDAR system 310, the controller assembly 320 can transfer energy E H Calculated as E H =MIN(AEL) 新平均值 AEL 每脉冲峰值 From Table 400 ( Figure 6 It was noted in the paper that the AEL of a light pulse with a width of 5 ns 每脉冲峰值 It is 200nJ (40W peak power).

[0161] AEL 新平均值 It can be calculated according to equation (4). However, in order to calculate AEL 新平均值 AEL 新总能量 The exposure angle α can be calculated based on an aperture of 395 mm with a diameter of 7 mm. The leader distance is equal to the optimal leader distance, which is 65 cm in this case. The exposure angle α can be calculated as follows: Considering that the horizontal resolution can be equal to 0.1°, the total number of light pulses N that can be received by an aperture of 395 can be equal to 0.6 / .01 = 6 pulses.

[0162] When the repetition rate is 10 μs (based on a repetition frequency of 100 kHz), the total time period of 6 optical pulses is 60 μs. Based on the total time of 60 μs and Table 400... Figure 6 ), will AEL 新总能量 The calculated value is 1226.4 nJ, corresponding to However, AEL of a 5ns wide optical pulse 每脉冲峰值 It is 200nJ (40W peak power). Therefore, E H =MIN(AEL) 新平均值 AEL 每脉冲峰值 = 200 nJ. The light source assembly 312 can be used to generate energy E.H The next light pulse is 200 nJ. Then, the light pulse is emitted to ROI 380.

[0163] It should be noted that in some embodiments, the LiDAR system emits a lead-in light pulse (e.g., 604) or a scanning light pulse (e.g., 606 or 610) at a single point in time.

[0164] It should be noted that the above embodiments do not limit the scope of the invention. For example, in various embodiments, the optical pulses may have different operating performance indicators in terms of pulse width, frequency, and repetition rate. In any case, AEL 总能量 AEL 平均值 AEL 每脉冲峰值 The optimal leader distance, leader pulse energy, or any of these parameters can be calculated based on the performance specifications of the light pulses generated and emitted by the LiDAR system 310.

[0165] Furthermore, in some embodiments, for a certain performance metric of the optical pulse, the energy E L or E H The values ​​can be predefined in a memory (e.g., 130) associated with the LiDAR system 310. The controller component 320 can be used to directly access these values ​​based on whether an object is detected by a lead-light pulse (e.g., 604). Furthermore, in some embodiments, the light source component 312 may include a pulse driver (not shown) to change the intensity of the light pulse.

[0166] Therefore, a prelead optical pulse with a low energy / power level is emitted, followed by an emission with an energy / power level E L or E H The light pulses improve the overall efficiency of the LiDAR system 310. For example, if the leader light pulse (e.g., 604) does not detect an object, the AEL of the scanning light pulse (e.g., 610) is improved. 平均值 It can be extended to AEL 每脉冲峰值 In some embodiments, for specific performance indicators of the optical pulse, AEL 平均值 It can be 133.5 nJ, which extends to an AEL value of 200 nJ. 每脉冲峰值 Therefore, the allowed energy may increase by approximately 49.8%. In this case, referring to equation (3), for objects of the same intensity, the maximum scanning range of these light pulses is equivalent to an increase of 22.4% compared to the original method.

[0167] For example, if the leading light pulse (e.g., 604) detects an object, the energy of the next light pulse can be equal to 123.5 nJ, a reduction of about 7.5%. In this case, referring to equation (3), for an image of the same intensity, the maximum scanning range of these light pulses is equivalent to a 4% reduction in the original scanning range.

[0168] If an object is detected within the optimal leader distance, the maximum scan range may be slightly reduced due to the dissipation of some energy in the leader pulse. However, since the object is detected at a very short distance from the LiDAR system 310, this effect can be ignored.

[0169] Furthermore, since the preamble and scan pulses use different pulse widths, the echo of the preamble after the scan pulse is emitted can be easily removed, and the possibility of erroneously detecting the preamble in the echo of the scan pulse is reduced.

[0170] Figure 15 This is a flowchart illustrating a process 700 involving a method implemented on a LiDAR system 310, provided by various embodiments of the present invention.

[0171] As shown in the figure, process 700 begins at step 702, where the radiation source emits light pulses toward the region of interest (ROI). As described above, the light source assembly 312 generates light pulses, and the scanner assembly 316 can guide the generated light pulses toward the ROI 380.

[0172] The process proceeds to step 704, where the detector detects the light pulse reflected from the ROI. As described above, the receiver assembly 318 receives or detects photons in the reflected light pulse and generates one or more representative data signals. For example, the receiver assembly 318 may generate an output electrical signal representing the reflected light pulse. The receiver assembly 318 may also provide the generated electrical signal to the controller assembly 320 for further processing.

[0173] The process proceeds to step 706, wherein a processor communicatively coupled to the radiation source causes the radiation source to emit energy E toward the ROI. P A lead light pulse with a width W1 is emitted. As described above, the controller assembly 320 coupled to the light source assembly 312 instructs the emission of a lead light pulse (e.g., 604). In one example, the energy E associated with the lead light pulse (e.g., 604) is... P It is 10 nJ, and the pulse width is 2 ns.

[0174] The process proceeds to step 708, where the processor, communicatively coupled to the detector, determines whether the detector has detected the pre-leading light pulse and whether an object is present in the ROI. As described above, the controller assembly 320, coupled to the receiver assembly 318, determines whether the receiver assembly 318 has detected the pre-leading light pulse (e.g., 604) and whether an object is present in the ROI 380.

[0175] Finally, in step 710, in response to determining that an object exists in the ROI, the processor causes the radiation source to emit radiation with energy E toward the ROI. L and a scanning light pulse with a width W2; otherwise, the processor causes the radiation source to emit a light pulse with energy E toward the ROI. H And the scanning light pulse with the width W2. As described above, in response to determining that an object is present in ROI 380, the controller assembly 320 causes the light source assembly 312 to emit a scanning light pulse with energy E. L A scan pulse with an energy of E (e.g., 125.5 nJ) and a pulse width W2 (e.g., 5 ns). Otherwise, if no object is detected in ROI 380, the controller assembly 320 causes the light source assembly 312 to emit a scan pulse with an energy of E H Scan pulses with a pulse width of W2 (e.g., 200 nJ) and a pulse width of W2 (e.g., 5 ns).

[0176] Therefore, determining the SNR of objects located at a greater distance can be achieved at low cost and high efficiency using the LiDAR system 310 and process 700 without adding too much hardware complexity.

[0177] It should be understood that the operation and functionality of the LiDAR system 310, its components, and associated processes can be implemented using any one or more hardware-based, software-based, and firmware-based elements. These operational alternatives do not limit the scope of the invention in any way.

[0178] It should also be understood that although the embodiments presented herein have been described with reference to specific features and structures, it will be apparent that various modifications and combinations can be made without departing from these disclosures. Therefore, the specification and drawings are to be regarded only as illustrative of the implementations or embodiments of the arguments and their principles as defined in the appended claims, and are intended to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of this invention.

Claims

1. A LiDAR system, characterized in that, The LiDAR system includes: A radiation source used to emit light pulses toward a region of interest (ROI); A detector is used to detect light pulses reflected from the ROI; A processor, communicatively coupled to the radiation source and the detector, is used for: This causes the radiation source to emit energy E towards the ROI. P The lead-in optical pulse with a pulse width W1; Determine whether the detector detects the lead-in light pulse and whether an object exists in the ROI; In response to determining the presence of an object in the ROI, the radiation source emits radiation with energy E toward the ROI. L And a scanning light pulse with a pulse width of W2; In response to determining that no object exists in the ROI, the radiation source emits energy E toward the ROI. H and the scanning light pulse with the pulse width W2; and a predetermined duration of waiting to determine whether the detector has detected the leader light pulse, the predetermined duration being calculated based on an optimal leader distance; wherein the optimal leader distance is based on the acceptable exposure limit (AEL) of the peak value of the light pulse. 每脉冲峰值 The width W2 and the repetition frequency f Calculated; wherein, the energy E p Less than the energy E L The energy E L Less than the energy E H The energy E H Less than or equal to the peak acceptable exposure limit (AEL) 每脉冲峰值 .

2. The LiDAR system according to claim 1, characterized in that, The energy E L =Standard acceptable exposure limit (AEL) 标准平均值 –E p .

3. The LiDAR system according to claim 1 or 2, characterized in that, The energy E H =MIN (New Acceptable Exposure Limit, AEL) 新平均值 Peak acceptable exposure limit (AEL) 每脉冲峰值 ).

4. The LiDAR system according to any one of claims 1 to 3, characterized in that, The pulse width W1 is smaller than the pulse width W2.

5. The LiDAR system according to any one of claims 1 to 4, characterized in that, The LiDAR system further includes: omitting the preleading light pulse received after the predetermined duration.

6. The LiDAR system according to any one of claims 1 to 5, characterized in that, The energy E P It is calculated based on the minimum estimated signal-to-noise ratio (SNR).

7. The LiDAR system according to claim 6, characterized in that, The minimum estimated signal-to-noise ratio is estimated using a Neyman Pearson detector.

8. A LiDAR method, characterized in that, The LiDAR method includes: The radiation source emits a light pulse toward the region of interest (ROI); The detector detects the light pulses reflected from the ROI; A processor coupled to the radiation source via communication causes the radiation source to emit energy E toward the ROI. P The lead-in optical pulse with a pulse width W1; The processor, which is communicatively coupled to the detector, determines whether the detector detects the lead-in light pulse and whether an object exists in the ROI; In response to determining that an object exists in the ROI, the processor causes the radiation source to emit radiation with energy E toward the ROI. L And a scanning light pulse with a pulse width of W2; In response to determining that no object exists in the ROI, the processor causes the radiation source to emit energy E toward the ROI. H and the scanning light pulse with the pulse width W2; and a predetermined duration of waiting to determine whether the detector has detected the leader light pulse, the predetermined duration being calculated based on an optimal leader distance; wherein the optimal leader distance is based on the acceptable exposure limit (AEL) of the peak value of the light pulse. 每脉冲峰值 The width W2 and the repetition frequency f Calculated; wherein, the energy E p Less than the energy E L The energy E L Less than the energy E H The energy E H Less than or equal to the peak acceptable exposure limit (AEL) 每脉冲峰值 .

9. The LiDAR method according to claim 8, characterized in that, The energy E L =Standard acceptable exposure limit (AEL) 标准平均值 –E P .

10. The LiDAR method according to claim 8 or 9, characterized in that, The energy E H =MIN (New Acceptable Exposure Limit, AEL) 新平均值 Peak acceptable exposure limit (AEL) 每脉冲峰值 ).

11. The LiDAR method according to any one of claims 8 to 10, characterized in that, The pulse width W1 is smaller than the pulse width W2.

12. The LiDAR method according to any one of claims 8 to 11, characterized in that, The LiDAR method further includes omitting the preleading light pulse received after the predetermined duration.

13. The LiDAR method according to any one of claims 8 to 12, characterized in that, The energy E P It is calculated based on the minimum estimated signal-to-noise ratio (SNR).

14. The LiDAR method according to claim 13, characterized in that, The minimum estimated signal-to-noise ratio is estimated using a Neyman Pearson detector.

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