Lidar system with pulse energy measurement

Abstract

A system for pulse energy measurement includes a light source, an optical splitter, and a pulse energy measurement circuit. The light source is configured to generate an emitted light beam comprising emitted light pulses. The optical splitter is configured to split the emitted light beam to produce at least (i) a test light beam comprising a test light pulse, the test light pulse comprising a first portion of the emitted light pulse, and (ii) an output light beam comprising an output light pulse, the output light pulse comprising a second portion of the emitted light pulse allowing at least partially exiting the system. The pulse energy measurement circuit is configured to receive a test light pulse and determine a value corresponding to an amount of individual energy of the test light pulse.

Description

[0001] Cross-references to other applications

[0002] This application claims the U.S. Provisional Patent Application No. 63 / 224,936, filed on July 23, 2021, entitled “LIDAR SYSTEM WITH PULSE-ENERGY MEASUREMENT,” which is incorporated herein by reference for all purposes. Technical Field

[0003] The present application relates to a lidar system with pulse energy measurement. Background Art

[0004] Light detection and ranging (LiDAR) is a technology that can be used to measure the distance to a remote target. Typically, a LiDAR system includes a light source and a light receiver. The light source may include, for example, a laser that emits light having a specific operating wavelength. The operating wavelength of a LiDAR system may be in, for example, the infrared, visible, or ultraviolet portion of the electromagnetic spectrum. The light source emits light toward a target that scatters the light, and some of the scattered light is received back at the receiver. The system determines the distance to the target based on one or more characteristics associated with the received light. For example, a LiDAR system can determine the distance to a target based on the flight time of a light pulse emitted by the light source to travel to the target and back to the LiDAR system. Utility Model Content

[0005] According to one aspect of the present disclosure, there is provided a system for pulse energy measurement, comprising: a light source configured to generate an emitted light beam comprising emitted light pulses; a beam splitter configured to split the emitted light beam to generate at least (i) a test light beam comprising a test light pulse, the test light pulse comprising a first portion of the emitted light pulse, and (ii) an output light beam comprising an output light pulse, the output light pulse comprising a second portion of the emitted light pulse allowed to at least partially leave the system; and a pulse energy measurement circuit configured to receive the test light pulses and determine a numerical value corresponding to an amount of a single energy of the test light pulses.

[0006] In one embodiment, the pulse energy measurement circuit comprises:

[0007] a detector configured to generate a photocurrent pulse corresponding to the test light pulse;

[0008] an electronic amplifier configured to generate a voltage pulse corresponding to the photocurrent pulse;

[0009] a peak hold circuit configured to generate a voltage signal corresponding to a peak value of the voltage pulse; and

[0010] An analog-to-digital converter (ADC) is configured to determine the numerical value corresponding to the amount of energy of the single test light pulse, wherein the numerical value is determined based on the voltage signal corresponding to the peak value of the voltage pulse.

[0011] In one embodiment, the pulse energy measurement circuit further includes a threshold detector configured to generate a trigger signal when the voltage signal rises above a specific threshold voltage, wherein the trigger signal is provided to the ADC to initiate determination by the ADC of the numerical value corresponding to the amount of the single energy of the test light pulse.

[0012] In one embodiment, the pulse energy measurement circuit further comprises a reset timer configured to provide a reset signal to the peak hold circuit at a specific time interval after the trigger signal is generated.

[0013] In one embodiment, the pulse energy measurement circuit further includes a buffer amplifier located between the peak hold circuit and the ADC, wherein the buffer amplifier is configured to receive the voltage signal corresponding to the peak value of the voltage pulse and generate an output signal corresponding to the received voltage signal, wherein the output signal is provided to the ADC.

[0014] In one embodiment, the pulse energy measurement circuit further comprises a timer configured to determine a reception time of the test light pulse.

[0015] In one embodiment, the pulse energy measurement circuit comprises:

[0016] a detector configured to generate a photocurrent pulse corresponding to the test light pulse;

[0017] an electronic amplifier configured to generate a voltage pulse corresponding to the photocurrent pulse; and

[0018] Multiple comparators and multiple time-to-digital converters (TDCs), where:

[0019] Each comparator of the plurality of comparators is coupled to a corresponding TDC of the TDCs and is configured to provide an electrical edge signal to the corresponding TDC when the voltage pulse rises above a specific threshold voltage or falls below a specific threshold voltage; and

[0020] The corresponding TDC is configured to generate a time value corresponding to a time when the electrical edge signal is received.

[0021] In one embodiment, the numerical value corresponding to the amount of the single energy of the test light pulse is determined based on one or more time values ​​generated by one or more of the TDCs.

[0022] In one embodiment, the beam splitter is configured to split the emitted light beam such that:

[0023] The amount of the single energy of the test light pulse is less than or equal to 2% of the energy of the emitted light pulse; and

[0024] The energy of the output light pulse is greater than or equal to 98% of the energy of the emitted light pulse.

[0025] In one embodiment, the emitted light pulse is one of a plurality of emitted light pulses generated by the light source, wherein the emitted light pulse has optical characteristics including the following:

[0026] Wavelengths between 900 nm and 1700 nm;

[0027] Pulse energies between 0.1 μJ and 100 μJ;

[0028] a pulse repetition frequency between 80 kHz and 10 MHz; and

[0029] Pulse duration between 1 ns and 100 ns.

[0030] In one embodiment, the light source comprises a direct emitter laser diode configured to generate the emitted light beam.

[0031] In one embodiment, the light source comprises:

[0032] a seed laser diode configured to generate seed light; and

[0033] A semiconductor optical amplifier (SOA) is configured to amplify the seed light to generate the emitted light beam.

[0034] In one embodiment, the light source comprises:

[0035] a seed laser diode configured to generate seed light; and

[0036] A fiber amplifier is configured to amplify the seed light to generate the emitted light beam.

[0037] In one embodiment, the light source comprises:

[0038] a seed laser diode configured to generate a seed light;

[0039] a semiconductor optical amplifier (SOA) configured to amplify the seed light to generate an amplified seed light; and

[0040] A fiber amplifier is configured to further amplify the amplified seed light to generate the emitted light beam.

[0041] In one embodiment, the system further comprises:

[0042] a scanner configured to scan the output beam across a field of view of the system;

[0043] a receiver configured to detect a received light pulse comprising a portion of the output light pulse scattered by an object located a distance from the system; and

[0044] A processor is configured to determine the distance from the system to the target based on a round trip time for the portion of the output light pulse to travel to the target and back to the system.

[0045] In one embodiment, the scanner comprises:

[0046] a first scanning mirror comprising a polygonal mirror configured to scan the output light beam along a first scanning axis to generate a plurality of scan lines; and

[0047] A second scanning mirror is configured to distribute the scan line along a second scanning axis different from the first scanning axis.

[0048] According to another aspect of the present disclosure, there is provided a method comprising: generating an emitted light beam comprising emitted light pulses; splitting the emitted light beam to produce at least (i) a test light beam comprising a test light pulse, the test light pulse comprising a first portion of the emitted light pulse, and (ii) an output light beam comprising an output light pulse, the output light pulse comprising a second portion of the emitted light pulse; generating a photocurrent pulse corresponding to the test light pulse; generating a voltage pulse corresponding to the photocurrent pulse; generating a voltage signal corresponding to a peak value of the voltage pulse; and determining a numerical value corresponding to an amount of a single energy of the test light pulse, wherein the numerical value is determined based on the voltage signal corresponding to the peak value of the voltage pulse.

[0049] According to another aspect of the present disclosure, there is provided a system comprising: a light source configured to generate an emitted light beam comprising an emitted light pulse; a beam splitter configured to split the emitted light beam to generate at least (i) a test light beam comprising a test light pulse, the test light pulse comprising a first portion of the emitted light pulse, and (ii) an output light beam comprising an output light pulse, the output light pulse comprising a second portion of the emitted light pulse allowed to at least partially leave the system; a pulse energy measurement circuit configured to receive the test light pulse and generate a digital numerical value corresponding to a voltage peak of the test light pulse; and a processor configured to determine the amount of a single energy of the test light pulse based on the digital numerical value corresponding to the voltage peak of the test light pulse. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various embodiments of the present invention are disclosed in the following detailed description and the accompanying drawings.

[0051] Figure 1 An example light detection and ranging (lidar) system is shown.

[0052] Figure 2 An example scan pattern produced by a lidar system is shown.

[0053] Figure 3 An example lidar system is shown with an example rotating polygonal mirror.

[0054] Figure 4 An example light source field of view (FOV) is shown for a LiDAR system. L ) and the receiver field of view (FOV R ).

[0055] Figure 5 An example unidirectional scan pattern including a plurality of pixels and a plurality of scan lines is shown.

[0056] Figure 6 An example light source, beam splitter, and pulse energy measurement circuit are shown.

[0057] Figure 7 An example free space beam splitter is shown.

[0058] Figure 8 An example fiber optic splitter is shown.

[0059] Fig. 9 An example light source, a beam splitter, and a pulse energy measurement circuit are shown, where the light source includes a seed laser diode and a semiconductor optical amplifier (SOA).

[0060] Fig.10An example light source, a beam splitter, and a pulse energy measurement circuit are shown, where the light source includes a seed laser diode, a semiconductor optical amplifier (SOA), and a fiber amplifier.

[0061] Fig.11 An example fiber amplifier is shown.

[0062] Fig.12 An example pulse energy measurement circuit including a peak hold circuit and an analog-to-digital converter (ADC) is shown.

[0063] Fig.13 An example pulse energy measurement circuit including a plurality of comparators and a time-to-digital converter (TDC) is shown.

[0064] Fig.14 An example lidar system including a beam splitter and pulse energy measurement circuitry is shown.

[0065] Fig.15 An example graph showing the optical power of an output beam plotted against time.

[0066] Fig.16 is a flow chart illustrating an embodiment of a process for a lidar system for detecting an object.

[0067] Fig.17 is a flow chart illustrating an embodiment of a process for monitoring light pulses of an emitted light beam.

[0068] Fig.18 is a flow chart illustrating an embodiment of a process for determining a monitoring measurement of a light pulse.

[0069] Fig.19 is a flow chart illustrating an embodiment of a process for initiating signal analysis of light pulses.

[0070] Fig. 20 is a flow chart illustrating an embodiment of a process for outputting a peak held voltage signal for measuring a light pulse.

[0071] Fig.21 An example computer system is shown. DETAILED DESCRIPTION

[0072] The utility model can be implemented in many ways, including as a process; an apparatus; a system; a composition of matter; a computer program product embodied on a computer-readable storage medium; and / or a processor, such as a processor configured to execute instructions stored on and / or provided by a memory coupled to the processor. In this specification, these implementations or any other form that the utility model can take can be referred to as technology. In general, the order of the steps of the disclosed process can be changed within the scope of the utility model. Unless otherwise specified, components such as processors or memories described as being configured to perform tasks can be implemented as general components that are temporarily configured to perform tasks at a given time or as specific components manufactured to perform tasks. As used herein, the term "processor" refers to one or more devices, circuits, and / or processing cores configured to process data (such as computer program instructions).

[0073] A detailed description of one or more embodiments of the present invention is provided below in conjunction with the accompanying drawings that illustrate the principles of the present invention. The present invention is described in conjunction with such embodiments, but the present invention is not limited to any embodiment. The scope of the present invention is limited only by the claims, and the present invention encompasses a variety of alternatives, modifications, and equivalents. In order to provide a thorough understanding of the present invention, many specific details are set forth in the following description. These details are provided for illustrative purposes, and the present invention can be practiced according to the claims without some or all of these specific details. For the sake of clarity, technical materials known in the technical field related to the present invention are not described in detail to avoid unnecessary ambiguity to the present invention.

[0074] A laser radar system with pulse energy measurement is disclosed. Using the disclosed systems and techniques, the pulse energy associated with a single output light pulse from the laser radar system can be measured. For example, using a pulse energy measurement circuit integrated into the laser radar system, the pulse energy of a single pulse can be measured at various points in the laser radar scan. In some embodiments, the laser radar output beam is split and a portion of the output beam is sent to the pulse energy circuit as a test pulse associated with the output pulse. The pulse energy circuit measures the peak voltage of the test pulse and can output a numerical value corresponding to the amount of single energy of the test pulse and the associated output pulse. In some embodiments, the pulse energy circuit is a pulse energy measurement circuit including a detector (such as a photodetector). The detector outputs a photocurrent associated with the test pulse, which is converted by the pulse energy measurement circuit into a corresponding voltage pulse. The voltage pulse is then analyzed by the pulse energy measurement circuit to determine a numerical value corresponding to the pulse energy of the test pulse. For example, the peak voltage can be detected and used to determine the corresponding numerical value. The processor and / or controller of the laser radar system determines the energy of the test and / or output pulse based on the determined corresponding numerical value.

[0075] In various embodiments, the output signal of the pulse energy measurement circuit can be used to monitor and / or manage the performance of the laser radar system. For example, pulse measurement can be used to provide feedback to reduce or increase the power of the output beam, such as reducing the laser output during the dark period and / or changing the laser output during the scan, such as changing the output according to the scan angle. In some embodiments, instructions can be sent to adjust the energy of the emitted light pulse, which causes the energy of the subsequently emitted pulse to be reduced to a level below a specific threshold energy. In various embodiments, the instructions are applied to the subsequently emitted light pulses such as directed by the scanner away from the window of the laser radar system during the dark period. In some embodiments, among other uses, pulse measurement can be used to improve the accuracy of laser radar results, such as improving reflectivity accuracy, and / or can be used to implement fault switching techniques, such as in the case of a detected fault. For example, if the pulse measurement is outside the expected operating range, an alarm can be triggered to resolve the detected situation. In some embodiments, the alarm is used to shut down the laser radar system or put the laser radar system into an auxiliary or fault switching mode. As another example, pulse energy measurement allows pulse output changes as a function of the energy field of view, such as when transitioning from the area of ​​interest to the periphery. The pulse energy measurement circuit allows confirmation that the output pulses corresponding to different areas of the energy field of view are within the expected value. In some embodiments, there may be a delay associated with the feedback provided by the pulse energy measurement, and the system takes this delay into account when measuring / modifying the output pulse.

[0076] In some embodiments, the system includes at least a light source, a spectrometer, and a pulse energy measurement circuit. For example, the laser radar system operates in a vehicle and includes at least a light source, a spectrometer, and a pulse energy measurement circuit. The light source is configured to generate an emitted light beam including an emitted light pulse. For example, the light source can emit one or more light pulses of a specific wavelength. The spectrometer is configured to split the emitted light beam to produce at least (i) a test light beam including a test light pulse, and (ii) an output light beam including an output light pulse. The test light pulse includes a first portion of the emitted light pulse. The output light pulse includes a second portion of the emitted light pulse that is allowed to at least partially leave the system. For example, the output light pulse leaves the laser radar system as part of a scanning technique for scanning an energy field of view. In various embodiments, the pulse energy measurement circuit is configured to receive the test light pulse and determine a numerical value corresponding to the amount of a single energy of the test light pulse. For example, the test light pulse is directed to a pulse energy measurement circuit, in which the peak voltage of the test pulse is measured. The measured value can be used to determine the corresponding measured value of the output light pulse. In various embodiments, a pulse energy measurement can be determined from the output of the pulse energy measurement circuit and used to determine whether the output pulses of light and / or the system are operating as expected, such as within an operating energy range. For example, if the test light pulse is found not to be operating as expected, such as outside of an operating energy range, an alarm can be triggered for the system, such as an alarm that the system is not operating properly. As another example, the pulse energy measurement can be used to send instructions to adjust the energy of one or more subsequently emitted output pulses and / or confirm that the energy of the subsequently emitted pulses is adjusted to be consistent with the instructions.

[0077] In some embodiments, the pulse energy measurement circuit includes a detector, an electronic amplifier, a peak hold circuit, and an analog-to-digital converter (ADC). The detector is configured to generate a photocurrent pulse corresponding to the test light pulse. The electronic amplifier is configured to generate a voltage pulse corresponding to the photocurrent pulse, and the peak hold circuit is configured to generate a voltage signal corresponding to the peak value of the voltage pulse. In various embodiments, the generated voltage signal corresponds to the peak voltage of the test light pulse. The ADC is configured to determine a numerical value corresponding to the energy of the test light pulse, wherein the numerical value is determined based on the voltage signal corresponding to the peak value of the voltage pulse. By determining the numerical value corresponding to the energy of the test light pulse, the energy of the output light pulse can also be determined. In various embodiments, the system uses the determined numerical value to monitor and / or adjust the operation of the system.

[0078] A lidar system operates in a vehicle and includes multiple "eyes," each with its own field of view or angular range, within which the eye scans for targets using pulses of light according to a scanning pattern. Fields of view can be combined along a particular dimension (e.g., horizontally) to define the lidar system's overall field of view. The lidar system can then use the data received via both eyes to generate a point cloud or otherwise process the received data.

[0079] In a binocular configuration of a LiDAR system, the two eyes can be housed together and scan the respective fields of view via a shared window or separate windows, or the eyes can be housed separately. In the latter case, a component called a "sensor head" may include a scanner, a receiver, and optical elements (such as a collimator or a laser diode) to generate or transmit a light beam.

[0080] Depending on the implementation, each eye of the lidar system can include a separate scanner (e.g., each eye can be equipped with a pivotable scanning mirror to scan the field of view vertically and another pivotable scanning mirror to scan the field of view horizontally), a partially shared scanner (e.g., each eye can be equipped with a pivotable scanning mirror to scan the field of view vertically, and the shared polygonal mirror can use different reflective surfaces to scan the corresponding field of view horizontally), or a fully shared scanner (e.g., a pivotable plane mirror can scan the field of view vertically by reflecting an incident light beam at different areas on the reflective surface, and the shared polygonal mirror can use different reflective surfaces to scan the corresponding field of view horizontally).

[0081] Different hardware configurations allow the lidar system to operate the eyes more independently of each other, as is the case with separate scanners, or less independently, as is the case with a fully shared scanner. For example, two or more eyes can scan corresponding energy fields using similar or different scanning patterns. In one implementation, the two eyes depict the same pattern, but with a certain time difference to maintain the angular separation between the light source fields of view and thereby reduce the probability of crosstalk events between sensor heads. In another implementation, at least in some operating conditions (e.g., when the vehicle turns right or left), the two eyes scan the corresponding energy fields according to different scanning patterns.

[0082] In addition, according to one approach, the two eyes of the lidar system are arranged so that the fields of view of the eyes are adjacent and do not overlap. For example, each field of view may span approximately 60 degrees horizontally and 30 degrees vertically, so that the combined field of view of the lidar system spans approximately 120 degrees horizontally and 30 degrees vertically. For example, corresponding scanners (or paths within a shared scanner) may be angled away from each other so that the respective fields of view are approximately adjacent to an axis corresponding to the forward direction of the vehicle.

[0083] Alternatively, the lidar system can be operated in a "cross-eye" configuration to create overlapping areas between fields of view. The overlapping area can be roughly centered along the forward direction or another direction, which can be determined dynamically by the controller in some implementations. In this implementation, the two sensor heads can produce a higher density of scans in areas that are generally more important. In some implementations, the fields of view in the cross-eye binocular configuration are offset from each other by half a pixel value so that the overlapping area has twice as many pixels. In general, the fields of view can overlap at an angle or translationally. In order to reduce the probability of crosstalk events (for example, a situation where a pulse emitted by a light source associated with a first eye is received by a receiver of a second eye), the lidar system can use output beams with different wavelengths.

[0084] Figure 1 An example light detection and ranging (LiDAR) system 100 is shown. In particular embodiments, the LiDAR system 100 may be referred to as a laser ranging system, a laser radar system, a LIDAR system, a laser radar sensor, or a laser detection and ranging (LADAR or LiDAR) system. In particular embodiments, the LiDAR system 100 may include a light source 110, a reflector 115, a scanner 120, a receiver 140, or a controller 150. The light source 110 may include, for example, a laser that emits light having a specific operating wavelength in the infrared, visible, or ultraviolet portion of the electromagnetic spectrum. As an example, the light source 110 may include one or more lasers having an operating wavelength between about 900 nanometers (nm) and 2000nm. The light source 110 emits an output light beam 125, which may be a continuous wave (CW) pulsed or modulated in any suitable manner for a given application. The output light beam 125 is directed to a remote target 130 along the emission direction. As an example, the remote target 130 may be located at a distance D of about 1m to 1km from the LiDAR system 100. Although Figure 1 Not shown, when outputting light pulses as part of the output light beam 125, the lidar system 100 may include a pulse energy measurement circuit as disclosed herein for determining the pulse energy associated with a single output light pulse.

[0085] Once the output beam 125 reaches the target 130 along the transmission direction, the target may scatter or reflect at least a portion of the light from the output beam 125, and some of the scattered or reflected light may return toward the lidar system 100. Figure 1In the example of FIG. 1 , the scattered or reflected light is represented by input beam 135, which passes through scanner 120 and is reflected by mirror 115 and directed to receiver 140. In certain embodiments, a relatively small portion of the light from output beam 125 may be returned to lidar system 100 as input beam 135. As an example, the ratio of the average power, peak power, or pulse energy of input beam 135 to the average power, peak power, or pulse energy of output beam 125 may be approximately 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7 , 10 -8 , 10 -9 , 10 -10 , 10 -11 or 10 -12 As another example, if a pulse of output beam 125 has a pulse energy of 1 microjoule (μJ), a corresponding pulse of input beam 135 may have a pulse energy of about 10 nanojoules (nJ), 1 nJ, 100 picojoules (pJ), 10 pJ, 1 pJ, 100 femtojoules (fJ), 10 fJ, 1 fJ, 100 attojoules (aJ), 10 aJ, 1 aJ, or 0.1 aJ. In some embodiments, the pulse energy of a pulse of input beam 135 may sometimes be as great as the pulse energy of a corresponding pulse of output beam 125.

[0086] In particular embodiments, the output beam 125 may include or may be referred to as an optical signal, an output optical signal, an emitted optical signal, an output light, an emitted optical pulse, a laser beam, an optical beam, an optical beam, an emitted beam, an emitted light, or an optical beam. In particular embodiments, the input beam 135 may include or may be referred to as a received optical signal, a received optical pulse, an input optical pulse, an input optical signal, a return beam, a received beam, a return light, a received light, an input light, scattered light, or reflected light. As used herein, scattered light may refer to light that is scattered or reflected by the target 130. As an example, the input beam 135 may include: light from the output beam 125 that is scattered by the target 130; light from the output beam 125 that is reflected by the target 130; or a combination of scattered light and reflected light from the target 130.

[0087] In certain embodiments, the receiver 140 may receive or detect photons from the input beam 135 and generate one or more representative signals. For example, the receiver 140 may generate an output electrical signal 145 representing the input beam 135, and the electrical signal 145 may be sent to the controller 150. In certain embodiments, the receiver 140 or the controller 150 may include a processor, a computing system (e.g., an ASIC or FPGA), or other suitable circuits. The controller 150 may be configured to analyze one or more characteristics of the electrical signal 145 from the receiver 140 to determine one or more characteristics of the target 130, such as its distance from the laser radar system 100 along the transmission direction. This can be done, for example, by analyzing the flight time or frequency or phase of the transmitted beam 125 or the received beam 135. If the lidar system 100 measures the time of flight of T (e.g., T represents the round-trip flight time for the emitted light pulse to travel from the lidar system 100 to the target 130 and back to the lidar system 100), then the distance D from the target 130 to the lidar system 100 can be expressed as D = c·T / 2, where c is the speed of light (approximately 3.0×10 8 m / s). As an example, if the flight time is measured as T=300ns, the distance from the target 130 to the lidar system 100 can be determined to be approximately D=45.0m. As another example, if the flight time is measured as T=1.33μs, the distance from the target 130 to the lidar system 100 can be determined to be approximately D=199.5m. In certain embodiments, the distance D from the lidar system 100 to the target 130 can be referred to as the distance, depth, or range of the target 130. As used herein, the speed of light c refers to the speed of light in any suitable medium, such as, for example, in air, water, or a vacuum. For example, the speed of light in a vacuum is approximately 2.9979×10 8 m / s, and the speed of light in air (which has a refractive index of about 1.0003) is about 2.9970×10 8 m / s.

[0088] In certain embodiments, the light source 110 may include a pulse or CW laser. As an example, the light source 110 may be a pulse laser configured to generate or emit light pulses having a pulse duration or pulse width of about 10 picoseconds (ps) to 100 nanoseconds (ns). The pulse may have a pulse duration of about 100ps, 200ps, 400ps, 1ns, 2ns, 5ns, 10ns, 20ns, 50ns, 100ns, or any other suitable pulse duration. As another example, the light source 110 may be a pulse laser that generates pulses having a pulse duration of about 1-5ns. As another example, the light source 110 may be a pulse laser that generates pulses with a pulse repetition frequency of about 100kHz to 10MHz or a pulse period (e.g., the time between consecutive pulses) of about 100ns to 10μs. In certain embodiments, the light source 110 may have a substantially constant pulse repetition frequency, or the light source 110 may have a variable or adjustable pulse repetition frequency. As an example, the light source 110 can be a pulsed laser that generates pulses at a substantially constant pulse repetition frequency of about 640 kHz (e.g., 640,000 pulses per second) corresponding to a pulse period of about 1.56 μs. As another example, the light source 110 can have a pulse repetition frequency (which can be referred to as a repetition rate) that can vary from about 200 kHz to 3 MHz. As used herein, light pulses can be referred to as optical pulses, light pulses, or pulses.

[0089] In some embodiments, the light source 110 can emit pulses of different wavelengths and with specific encoding time delays between pulses of different wavelengths. For example, two different pulse groups can each include pulses of different wavelengths, and each pulse group can utilize a different encoding time delay.

[0090] In certain embodiments, the light source 110 may include a pulsed or CW laser that produces a free-space output beam 125 having any suitable average optical power. As an example, the output beam 125 may have an average power of approximately 1 milliwatt (mW), 10mW, 100mW, 1 watt (W), 10W, or any other suitable average power. In certain embodiments, the output beam 125 may include light pulses having any suitable pulse energy or peak optical power. As an example, the output beam 125 may include pulses having a pulse energy of approximately 0.01μJ, 0.1μJ, 0.5μJ, 1μJ, 2μJ, 10μJ, 100μJ, 1mJ, or any other suitable pulse energy. As another example, the output beam 125 may include pulses having a peak power of approximately 10W, 100W, 1kW, 5kW, 10kW, or any other suitable peak power. The peak power (P peak ) can be expressed by E = P peakΔt is related to the pulse energy (E), where Δt is the duration of the pulse, and the duration of a pulse can be defined as the full width at half maximum duration of the pulse. For example, a light pulse with a duration of 1 ns and a pulse energy of 1 μJ has a peak power of about 1 kW. The average power (P av ) can be expressed by P av =PRF·E is related to the pulse repetition frequency (PRF) and the pulse energy. For example, if the pulse repetition frequency is 500 kHz, the average power of the output beam 125 with 1 μJ pulses is about 0.5W.

[0091] In certain embodiments, the light source 110 may include a laser diode, such as, for example, a Fabry-Perot laser diode, a quantum well laser, a distributed Bragg reflector (DBR) laser, a distributed feedback (DFB) laser, a vertical cavity surface emitting laser (VCSEL), a quantum dot laser diode, a grating coupled surface emitting laser (GCSEL), a slab coupled optical waveguide laser (SCOWL), a single transverse mode laser diode, a multimode large area laser diode, a laser diode bar, a laser diode stack, or a tapered stripe laser diode. As an example, the light source 110 may include an aluminum gallium arsenide (AlGaAs) laser diode, an indium gallium arsenide (InGaAs) laser diode, an indium gallium arsenide phosphide (InGaAsP) laser diode, or a laser diode including any suitable combination of aluminum (Al), indium (In), gallium (Ga), arsenic (As), phosphorus (P), or any other suitable material. In certain embodiments, the light source 110 may include a pulsed or CW laser diode having a peak emission wavelength between 1200 nm and 1600 nm. As an example, the light source 110 may include a current modulated InGaAsP DFB laser diode that produces light pulses at a wavelength of about 1550 nm. As another example, the light source 110 may include a laser diode that emits light at a wavelength between 1500 nm and 1510 nm.

[0092] In certain embodiments, the light source 110 may include a pulsed or CW laser diode, followed by one or more optical amplification stages. For example, a seed laser diode may generate a seed optical signal, and an optical amplifier may amplify the seed optical signal to generate an amplified optical signal emitted by the light source 110. In certain embodiments, the optical amplifier may include a fiber amplifier or a semiconductor optical amplifier (SOA). For example, a pulsed laser diode may generate a relatively low-power optical seed pulse amplified by a fiber amplifier. As another example, the light source 110 may include a fiber laser module including a current-modulated laser diode having an operating wavelength of about 1550 nm, followed by a single-stage or multi-stage erbium-doped fiber amplifier (EDFA) or erbium-ytterbium co-doped fiber amplifier (EYDFA) that amplifies the seed pulse from the laser diode. As another example, the light source 110 may include a continuous wave (CW) or quasi-CW laser diode, followed by an external optical modulator (e.g., an electro-optical amplitude modulator). The optical modulator may modulate the CW light from the laser diode to generate an optical pulse sent to the fiber amplifier or SOA. As another example, the light source 110 may include a pulsed or CW seed laser diode, followed by a semiconductor optical amplifier (SOA). The SOA may include an active optical waveguide configured to receive light from the seed laser diode and amplify the light as it propagates through the waveguide. The optical gain of the SOA may be provided by a pulsed or direct current (DC) current provided to the SOA. The SOA may be integrated on the same chip as the seed laser diode, or the SOA may be a separate device having an anti-reflection coating on its input end face or output end face. As another example, the light source 110 may include a seed laser diode, followed by the SOA, which in turn is a fiber amplifier. For example, the seed laser diode may generate a relatively low-power seed pulse that is amplified by the SOA, and the fiber amplifier may further amplify the optical pulse.

[0093] In certain embodiments, the light source 110 may include a direct emitter laser diode. A direct emitter laser diode (which may be referred to as a direct emitter) may include a laser diode that produces light that is not subsequently amplified by an optical amplifier. The light source 110 including a direct emitter laser diode may not include an optical amplifier, and the output light produced by the direct emitter may not be amplified after being emitted by the laser diode. The light (e.g., light pulses, CW light, or frequency modulated light) produced by the direct emitter laser diode may be emitted directly as a free space output beam 125 without amplification. The direct emitter laser diode may be driven by a power supply that provides current pulses to the laser diode, and each current pulse may result in the emission of an output light pulse.

[0094] In certain embodiments, the light source 110 may include a diode-pumped solid-state (DPSS) laser. A DPSS laser (which may be referred to as a solid-state laser) may refer to a laser that includes a solid-state, glass, ceramic, or crystal-based gain medium pumped by one or more pump laser diodes. The gain medium may include a host material doped with rare earth ions (e.g., neodymium, erbium, ytterbium, or praseodymium). For example, the gain medium may include an yttrium aluminum garnet (YAG) crystal doped with neodymium (Nd) ions, and the gain medium may be referred to as an Nd:YAG crystal. A DPSS laser with an Nd:YAG gain medium may generate light at a wavelength between about 1300 nm and about 1400 nm, and the Nd:YAG gain medium may be pumped by one or more pump laser diodes having an operating wavelength between about 730 nm and about 900 nm. The DPSS laser may be a passive Q-switched laser that includes a saturable absorber (e.g., a vanadium-doped crystal that acts as a saturable absorber). Alternatively, the DPSS laser can be an actively Q-switched laser including an active Q-switch (eg, an acousto-optic modulator or an electro-optic modulator). A passive or actively Q-switched DPSS laser can generate output light pulses that form the output beam 125 of the lidar system 100 .

[0095] In certain embodiments, the output beam 125 emitted by the light source 110 may be a collimated beam having any suitable beam divergence angle, such as, for example, a full-angle beam divergence angle of about 0.5 to 10 milliradians (mrad). The divergence angle of the output beam 125 may refer to an angular measure of the increase in beam size (e.g., beam radius or beam diameter) as the output beam 125 travels away from the light source 110 or the laser radar system 100. In certain embodiments, the output beam 125 may have a substantially circular cross-section, and its beam divergence angle is characterized by a single divergence angle value. As an example, an output beam 125 having a circular cross-section and a full-angle beam divergence angle of 2 mrad may have a beam diameter or spot size of about 20 cm at a distance of 100 m from the laser radar system 100. In certain embodiments, the output beam 125 may have a substantially elliptical cross-section characterized by two divergence angle values. As an example, the output beam 125 may have a fast axis and a slow axis, wherein the fast axis divergence angle is greater than the slow axis divergence angle. As another example, the output beam 125 may be an elliptical beam having a fast-axis divergence angle of 4 mrad and a slow-axis divergence angle of 2 mrad.

[0096] In certain embodiments, the output light beam 125 emitted by the light source 110 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 output light beam 125 may be linearly polarized, elliptically polarized, or circularly polarized). As an example, the light source 110 may generate light that has no specific polarization or may generate linearly polarized light.

[0097] In certain embodiments, the laser radar system 100 may include one or more optical components configured to reflect, focus, filter, shape, modify, steer, or direct light within the laser radar system 100 or light generated or received by the laser radar system 100 (e.g., output beam 125 or input beam 135). As an example, the laser radar system 100 may include one or more lenses, mirrors, filters (e.g., bandpass or interference filters), beam splitters, beam splitters, polarizers, polarization beam splitters, wave plates (e.g., half-wave or quarter-wave plates), diffractive elements, holographic elements, isolators, couplers, detectors, beam combiners, or collimators. The optical components in the laser radar system 100 may be free-space optical components, fiber-coupled optical components, or a combination of free-space and fiber-coupled optical components.

[0098] In certain embodiments, the laser radar system 100 may include a telescope, one or more lenses, or one or more mirrors configured to expand, focus, or collimate the output beam 125 or the input beam 135 to a desired beam diameter or divergence angle. As an example, the laser radar system 100 may include one or more lenses to focus the input beam 135 onto a photodetector of the receiver 140. As another example, the laser radar system 100 may include one or more plane mirrors or curved mirrors (e.g., concave mirrors, convex mirrors, or parabolic mirrors) to steer or focus the output beam 125 or the input beam 135. For example, the laser radar system 100 may include an off-axis parabolic mirror to focus the input beam 135 onto the photodetector of the receiver 140. Figure 1As shown in , the laser radar system 100 may include a reflector 115 (which may be a metal or dielectric reflector), and the reflector 115 may be configured so that the light beam 125 passes through the reflector 115 or passes along the edge or side of the reflector 115 and the input light beam 135 is reflected toward the receiver 140. As an example, the reflector 115 (which may be referred to as an overlapping reflector, a superimposed reflector, or a beam combining reflector) may include a hole, slot, or aperture through which the output light beam 125 passes. As another example, instead of passing through the reflector 115, the output light beam 125 may be directed to pass beside the reflector 115 with a gap between the output light beam 125 and the edge of the reflector 115 (e.g., a gap with a width of about 0.1 mm, 0.5 mm, 1 mm, 2 mm, 5 mm, or 10 mm).

[0099] In certain embodiments, the reflector 115 can cause the output beam 125 and the input beam 135 to be substantially coaxial, such that the two beams travel along approximately the same optical path (although in opposite directions). The input beam and the output beam being substantially coaxial can refer to the beams at least partially overlapping or sharing a common propagation axis, such that the input beam 135 and the output beam 125 travel along substantially the same optical path (although in opposite directions). As an example, the output beam 125 and the input beam 135 can be parallel to each other to within less than 10 mrad, 5 mrad, 2 mrad, 1 mrad, 0.5 mrad, or 0.1 mrad. As the output beam 125 scans across the energy field of view, the input beam 135 can follow along with the output beam 125 so that the coaxial relationship between the two beams is maintained.

[0100] In certain embodiments, the laser radar system 100 may include a scanner 120 configured to scan an output beam 125 across the field of view of the laser radar system 100. As an example, the scanner 120 may include one or more scanning mirrors configured to pivot, rotate, swing, or move in an angular manner around one or more rotation axes. The output beam 125 may be reflected by the scanning mirror, and as the scanning mirror pivots or rotates, the reflected output beam 125 may be scanned in a corresponding angular manner. As an example, the scanning mirror may be configured to pivot back and forth periodically within a 30 degree range, which causes the output beam 125 to scan back and forth across a 60 degree range (e.g., a θ degree rotation of the scanning mirror causes a 2θ degree angular scan of the output beam 125).

[0101] In certain embodiments, the scanning mirror (which may be referred to as a scanning mirror) may be attached to or mechanically driven by a scanner actuator or mechanism that pivots or rotates the mirror within a specific angular range (e.g., within a 5° angular range, a 30° angular range, a 60° angular range, a 120° angular range, a 360° angular range, or any other suitable angular range). The scanner actuator or mechanism configured to pivot or rotate the mirror may include a galvanometer scanner, a resonant scanner, a piezoelectric actuator, a voice coil motor, an electric motor (e.g., a DC motor, a brushless DC motor, a synchronous motor, or a stepper motor), a microelectromechanical system (MEMS) device, or any other suitable actuator or mechanism. As an example, the scanner 120 may include a scanning mirror attached to a galvanometer scanner that is configured to pivot back and forth within an angular range of 1° to 30°. As another example, the scanner 120 may include a scanning mirror attached to or part of a MEMS device configured to scan within an angular range of 1° to 30°. As another example, the scanner 120 may include a polygonal mirror configured to continuously rotate in the same direction (e.g., instead of pivoting back and forth, the polygonal mirror continuously rotates 360 degrees in a clockwise or counterclockwise direction). The polygonal mirror may be coupled or attached to a synchronous motor configured to rotate the polygonal mirror at a substantially fixed rotational frequency (e.g., a rotational frequency of approximately 1 Hz, 10 Hz, 50 Hz, 100 Hz, 500 Hz, or 1000 Hz).

[0102] In certain embodiments, the scanner 120 may be configured to scan an output beam 125 (which may include at least a portion of the light emitted by the light source 110) across the field of view of the laser radar system 100. The field of view (FOR) of the laser radar system 100 may refer to an area, region, or angular range over which the laser radar system 100 may be configured to scan or capture distance information. As an example, a laser radar system 100 having an output beam 125 with a 30-degree scanning range may be referred to as having a 30-degree angular field of view. As another example, a laser radar system 100 having a scanning mirror that rotates within a 30-degree range may produce an output beam 125 that scans across a 60-degree range (e.g., a 60-degree FORR). In certain embodiments, the laser radar system 100 may have a FOR of approximately 10°, 20°, 40°, 60°, 120°, 360°, or any other suitable FOR.

[0103] In certain embodiments, the scanner 120 may be configured to scan the output beam 125 horizontally and vertically, and the laser radar system 100 may have a specific FOR in the horizontal direction and another specific FOR in the vertical direction. As an example, the laser radar system 100 may have a horizontal FOR of 10° to 120° and a vertical FOR of 2° to 45°. In certain embodiments, the scanner 120 may include a first scanning mirror and a second scanning mirror, wherein the first scanning mirror guides the output beam 125 toward the second scanning mirror, and the second scanning mirror guides the output beam 125 toward the down-transmission direction of the laser radar system 100. As an example, the first scanning mirror may scan the output beam 125 in a first direction, and the second scanning mirror may scan the output beam 125 in a second direction substantially orthogonal to the first direction. As another example, the first scanning mirror may scan the output beam 125 in a substantially horizontal direction, and the second scanning mirror may scan the output beam 125 in a substantially vertical direction (or vice versa). As another example, the first and second scanning mirrors may each be driven by a galvanometer scanner. As another example, the first or second scanning mirror may include a polygon mirror driven by a motor.In certain embodiments, the scanner 120 may be referred to as a beam scanner, an optical scanner, or a laser scanner.

[0104] In certain embodiments, one or more scanning mirrors may be communicatively coupled to a controller 150, which may control the scanning mirrors to direct the output beam 125 in a desired direction along the emission direction or along a desired scanning pattern. In certain embodiments, the scanning pattern may refer to a pattern or path along which the output beam 125 is directed. As an example, the scanner 120 may include two scanning mirrors configured to scan the output beam 125 across a 60° horizontal FOR and a 20° vertical FOR. The two scanner mirrors may be controlled to follow a scanning path that substantially covers 60°×20°FOR. As an example, the scanning path may result in a point cloud having pixels that substantially cover 60°×20°FOR. The pixels may be distributed approximately uniformly across 60°×20°FOR. Alternatively, the pixels may have a specific non-uniform distribution (e.g., the pixels may be distributed across all or a portion of 60°×20°FOR, and the pixels may have a higher density in one or more specific areas of 60°×20°FOR).

[0105] In certain embodiments, the laser radar system 100 may include a scanner 120 having a solid-state scanning device. A solid-state scanning device may refer to a scanner 120 that scans the output beam 125 without using moving parts (e.g., without using a mechanical scanner, such as a rotating or pivoting mirror). For example, the solid-state scanner 120 may include one or more of the following: an optical phased array scanning device; a liquid crystal scanning device; or a liquid lens scanning device. The solid-state scanner 120 may be an electrically addressed device that scans the output beam 125 along one axis (e.g., horizontally) or along two axes (e.g., horizontally and vertically). In certain embodiments, the scanner 120 may include a solid-state scanner and a mechanical scanner. For example, the scanner 120 may include an optical phased array scanner configured to scan the output beam 125 in one direction and a galvanometer scanner that scans the output beam 125 in an orthogonal direction. The optical phased array scanner can scan the output beam relatively quickly in the horizontal direction across the field of view (e.g., at a scan rate of 50 to 1,000 scan lines per second), and the galvanometer can pivot the mirror at a rate of 1-30 Hz to scan the output beam 125 vertically.

[0106] In certain embodiments, the laser radar system 100 may include a light source 110 configured to emit light pulses and a scanner 120 configured to scan at least a portion of the emitted light pulses across the field of view of the laser radar system 100. One or more of the emitted light pulses may be scattered by a target 130 located along the emission direction of the laser radar system 100, and a receiver 140 may detect at least a portion of the light pulses scattered by the target 130. The receiver 140 may be referred to as an optical receiver, an optical receiver, an optical sensor, a detector, a photodetector, or an optical detector. In certain embodiments, the laser radar system 100 may include a receiver 140 that receives or detects at least a portion of an input light beam 135 and generates an electrical signal corresponding to the input light beam 135. As an example, if the input light beam 135 includes light pulses, the receiver 140 may generate a current or voltage pulse corresponding to the light pulses detected by the receiver 140. As another example, the receiver 140 may include one or more avalanche photodiodes (APDs) or one or more single photon avalanche diodes (SPADs). As another example, the receiver 140 may include one or more PN photodiodes (e.g., a photodiode structure formed of a p-type semiconductor and an n-type semiconductor, where the PN acronym refers to a structure having p-doped and n-doped regions) or one or more PIN photodiodes (e.g., a photodiode structure formed of an undoped intrinsic semiconductor region between a p-type and an n-type region, where the PIN acronym refers to a structure having p-doped, intrinsic, and n-doped regions). An APD, SPAD, PN photodiode, or PIN photodiode may each be referred to as a detector, a photodetector, or a photodiode. The detector may have an active region or avalanche multiplication region that includes silicon, germanium, InGaAs, InAsSb (indium antimony arsenide), AlAsSb (aluminum antimony arsenide), or AlInAsSb (aluminum indium arsenide antimonide). The active region may refer to an area where the detector may receive or detect input light. The active area may have any suitable size or diameter, such as, for example, a diameter of about 10 μm, 25 μm, 50 μm, 80 μm, 100 μm, 200 μm, 500 μm, 1 mm, 2 mm, or 5 mm.

[0107] In certain embodiments, the receiver 140 may include electronic circuits that perform signal amplification, sampling, filtering, signal conditioning, analog-to-digital conversion, time-to-digital conversion, pulse detection, threshold detection, rising edge detection, or falling edge detection. As an example, the receiver 140 may include a transimpedance amplifier that converts a received photocurrent (e.g., a current generated by the APD in response to a received light signal) into a voltage signal. The voltage signal may be sent to a pulse detection circuit that generates an analog or digital output signal 145 that corresponds to one or more optical characteristics of the received light pulse (e.g., a rising edge, a falling edge, an amplitude, a duration, or an energy). As an example, the pulse detection circuit may perform a time-to-digital conversion to generate a digital output signal 145. The electrical output signal 145 may be sent to the controller 150 for processing or analysis (e.g., to determine a time-of-flight value corresponding to the received light pulse).

[0108] In certain embodiments, the controller 150 (which may include or may be referred to as a processor, FPGA, ASIC, computer, or computing system) may be located within the laser radar system 100 or outside the laser radar system 100. Alternatively, one or more portions of the controller 150 may be located within the laser radar system 100, and one or more other portions of the controller 150 may be located outside the laser radar system 100. In certain embodiments, one or more portions of the controller 150 may be located within the receiver 140 of the laser radar system 100, and one or more other portions of the controller 150 may be located in other portions of the laser radar system 100. For example, the receiver 140 may include an FPGA or an ASIC configured to process output electrical signals from the receiver 140, and the processed signals may be sent to a computing system located elsewhere within the laser radar system 100 or outside the laser radar system 100. In certain embodiments, the controller 150 may include any suitable arrangement or combination of logic circuits, analog circuits, or digital circuits.

[0109] In certain embodiments, the controller 150 may be electrically coupled or communicatively coupled to the light source 110, the scanner 120, or the receiver 140. As an example, the controller 150 may receive electrical trigger pulses or edges from the light source 110, wherein each pulse or edge corresponds to a light pulse emitted by the light source 110. As another example, the controller 150 may provide instructions, control signals, trigger signals, and / or other appropriate control signals to the light source 110, indicating when the light source 110 should generate a light pulse and / or a light source configuration associated with the generated light pulse, such as a desired wavelength of the light pulse. As another example, the controller 150 may provide a control signal to attenuate (including disabling and / or enabling) light generated by and emitted from the light source 110. For example, the controller 150 may be used to disable the emission of a light beam from the laser radar system 100 when the light beam is not aimed at the target 130. The controller 150 may send an electrical trigger signal including an electrical pulse, wherein each electrical pulse results in the emission of a light pulse by the light source 110. In certain embodiments, the frequency, period, duration, pulse energy, peak power, average power, or wavelength of the light pulses generated by the light source 110 may be adjusted based on instructions, control signals, or trigger pulses provided by the controller 150. In certain embodiments, the controller 150 may be coupled to the light source 110 and the receiver 140, and the controller 150 may determine a time-of-flight value of the light pulse based on timing information associated with when the light source 110 transmits the pulse and when the receiver 140 detects or receives a portion of the pulse (e.g., the input light beam 135). In certain embodiments, the controller 150 may include circuits that perform signal amplification, sampling, filtering, signal conditioning, analog-to-digital conversion, time-to-digital conversion, pulse detection, threshold detection, rising edge detection, or falling edge detection.

[0110] In certain embodiments, the lidar system 100 may include one or more processors (e.g., controller 150) configured to determine a distance D from the lidar system 100 to the target 130 based at least in part on a round-trip flight time for an emitted light pulse to travel from the lidar system 100 to the target 130 and back to the lidar system 100. The target 130 may be at least partially contained within the field of view of the lidar system 100 and located at a distance from the lidar system 100 that is less than or equal to the operating range (R) of the lidar system 100. OP) at a distance D of the laser radar system 100. In certain embodiments, the operating range of the laser radar system 100 (which may be referred to as the operating range) may refer to the distance at which the laser radar system 100 is configured to sense or identify targets 130 located in the field of view of the laser radar system 100. The operating range of the laser radar system 100 may be any suitable distance, such as, for example, 25m, 50m, 100m, 200m, 250m, 500m, or 1km. As an example, a laser radar system 100 with a 200m operating range may be configured to sense or identify various targets 130 that are up to 200m away from the laser radar system 100. The operating range R of the laser radar system 100 OP The expression R OP = c·τ / 2 is related to the time τ between the transmissions of consecutive optical signals. For an operating range of 200 m (R OP =200m) of the laser radar system 100, the time τ between consecutive pulses (which may be referred to as the pulse period, pulse repetition interval (PRI) or the time period between pulses) is approximately The pulse period τ can also correspond to the pulse traveling back and forth 100 distance R from the laser radar system OP The flight time of the target 130 is calculated. In addition, the pulse period τ can be related to the pulse repetition frequency (PRF) by the expression τ=1 / PRF. For example, a pulse period of 1.33 μs corresponds to a PRF of about 752 kHz.

[0111] In a particular embodiment, the laser radar system 100 can be used to determine the distance to one or more targets 130 along the transmission direction. By scanning the laser radar system 100 across the field of view, the system can be used to map the distance to many points within the field of view. Each of these depth mapping points can be referred to as a pixel or voxel. A continuously captured set of pixels (which can be referred to as a depth map, point cloud, or frame) can be rendered as an image or can be analyzed to identify or detect an object or determine the shape or distance of an object within the FOR. As an example, a point cloud can cover a field of view extending 60° horizontally and 15° vertically, and the point cloud can include a frame of 100-2000 pixels in the horizontal direction × 4-400 pixels in the vertical direction.

[0112] In certain embodiments, the lidar system 100 may be configured to repeatedly capture or generate a point cloud of the field of view at any suitable frame rate between about 0.1 frames per second (FPS) and about 1000 FPS. As an example, the lidar system 100 may generate a point cloud at a frame rate of about 0.1 FPS, 0.5 FPS, 1 FPS, 2 FPS, 5 FPS, 10 FPS, 20 FPS, 100 FPS, 500 FPS, or 1000 FPS. As another example, the lidar system 100 may be configured to generate a point cloud at a frame rate of 5×10 5The laser radar system 100 may generate light pulses at a rate of 1000 pulses / second (e.g., the system may determine a distance of 500,000 pixels per second) and scan a frame of 1000×50 pixels (e.g., 50,000 pixels / frame), which corresponds to a point cloud frame rate of 10 frames per second (e.g., 10 point clouds per second). In certain embodiments, the point cloud frame rate may be substantially fixed, or the point cloud frame rate may be dynamically adjustable. As an example, the laser radar system 100 may capture one or more point clouds at a particular frame rate (e.g., 1 Hz), and then switch to capturing one or more point clouds at a different frame rate (e.g., 10 Hz). A slower frame rate (e.g., 1 Hz) may be used to capture one or more high-resolution point clouds, and a faster frame rate (e.g., 10 Hz) may be used to quickly capture multiple lower-resolution point clouds.

[0113] In certain embodiments, the light source 110, the scanner 120, and the receiver 140 may be packaged together in a single housing, wherein the housing may refer to a box, a shell, or a housing that houses or contains all or part of the laser radar system 100. As an example, the laser radar system housing may contain the light source 110, the reflector 115, the scanner 120, and the receiver 140 of the laser radar system 100. In addition, the laser radar system housing may include a controller 150. The laser radar system housing may also include one or more electrical connections for transmitting electrical power or electrical signals to or from the housing. In certain embodiments, one or more components of the laser radar system 100 may be located away from the laser radar system housing. As an example, all or part of the light source 110 may be located away from the laser radar system housing, and the light pulses generated by the light source 110 may be transmitted to the housing via optical fiber. As another example, all or part of the controller 150 may be located away from the laser radar system housing.

[0114] In certain embodiments, the light source 110, the scanner 120, and the receiver 140 may be packaged together in a single housing, wherein the housing may refer to a box, case, or housing that houses or contains all or part of the laser radar system 100. As an example, the laser radar system housing may contain the light source 110, the mirror 115, the scanner 120, and the receiver 140 of the laser radar system 100. In addition, the laser radar system housing may include a controller 150. The laser radar system housing may also include one or more electrical connections for transmitting power or electrical signals to or from the housing. In certain embodiments, one or more components of the laser radar system 100 may be located away from the laser radar system housing. As an example, all or part of the light source 110 may be located away from the laser radar system housing, and the light pulses generated by the light source 110 may be transmitted to the housing via optical fiber. As another example, all or part of the controller 150 may be located away from the laser radar system housing.

[0115] In certain embodiments, the light source 110 may include an eye-safe laser, or the laser radar system 100 may be classified as an eye-safe laser system or laser product. An eye-safe laser, laser system, or laser product may refer to a system that includes a laser having an emission wavelength, average power, peak power, peak intensity, pulse energy, beam size, beam divergence angle, exposure time, or scanned output beam, such that the light emitted from the system is less likely to cause damage to a person's eyes or no damage. As an example, the light source 110 or the laser radar system 100 may be classified as a Class 1 laser product (as specified in the 60825-1:2014 standard of the International Electrotechnical Commission (IEC)) or a Class I laser product (as specified in Section 1040.10 of Title 21 of the United States Code of Federal Regulations (CFR)). In certain embodiments, the laser radar system 100 may be an eye-safe laser product (e.g., having a Class 1 or Class I classification) configured to operate at any suitable wavelength between about 900 nm and about 2100 nm. As an example, the laser radar system 100 may include a laser having an operating wavelength between about 1200 nm and about 1400 nm or between about 1400 nm and about 1600 nm, and the laser or the laser radar system 100 may be operated in an eye-safe manner. As another example, the laser radar system 100 may be an eye-safe laser product that includes a scanning laser having an operating wavelength between about 900 nm and about 1700 nm. As another example, the laser radar system 100 may be a Class 1 or Class I laser product that includes a laser diode, a fiber laser, or a solid-state laser having an operating wavelength between about 1200 nm and about 1600 nm. As another example, the laser radar system 100 may have an operating wavelength between about 1500 nm and about 1550 nm.

[0116] In certain embodiments, one or more laser radar systems 100 may be integrated into a vehicle. As an example, multiple laser radar systems 100 may be integrated into a car to provide a complete 360-degree horizontal FOR around the car. As another example, 2-10 laser radar systems 100, each with a horizontal FOR of 45 to 180 degrees, may be combined to form a sensing system that provides a point cloud covering a 360-degree horizontal FOR. The laser radar system 100 may be oriented so that adjacent FORs have a certain amount of spatial or angular overlap to allow data from multiple laser radar systems 100 to be combined or stitched together to form a single or continuous 360-degree point cloud. As an example, the FOR of each laser radar system 100 may have an overlap of approximately 1-30 degrees with an adjacent FOR. In certain embodiments, a vehicle may refer to a mobile machine configured to transport people or goods. For example, a vehicle may include, may take the form of, or may be referred to as, a car, an automobile, a motor vehicle, a truck, a bus, a van, a trailer, an off-road vehicle, a farm vehicle, a lawn mower, construction equipment, a forklift, a robot, a golf cart, an RV, a taxi, a motorcycle, a scooter, a bicycle, a skateboard, a train, a snowmobile, a watercraft (e.g., a ship or a boat), an aircraft (e.g., a fixed-wing aircraft, a helicopter, or a dirigible), an unmanned aerial vehicle (e.g., a drone), or a spacecraft. In certain embodiments, a vehicle may include an internal combustion engine or an electric motor to provide propulsion for the vehicle.

[0117] In certain embodiments, one or more lidar systems 100 may be included in a vehicle as part of an advanced driver assistance system (ADAS) to assist the driver of the vehicle in operating the vehicle. For example, the lidar system 100 may be part of an ADAS that provides information (e.g., about the surrounding environment) or feedback (e.g., alerting the driver to potential problems or hazards) to the driver or automatically controls a portion of the vehicle (e.g., a braking system or a steering system) to avoid a collision or accident. The lidar system 100 may be part of a vehicle ADAS that provides adaptive cruise control, automatic braking, automatic parking, collision avoidance, alerts the driver to hazards or other vehicles, keeps the vehicle in the correct lane, or provides warnings when an object or another vehicle is in a blind spot.

[0118] In certain embodiments, one or more laser radar systems 100 may be integrated into a vehicle as part of an autonomous vehicle driving system. As an example, the laser radar system 100 may provide information about the surrounding environment to the driving system of the autonomous vehicle. The autonomous vehicle driving system may be configured to guide the autonomous vehicle through the environment around the vehicle and toward the destination. The autonomous vehicle driving system may include one or more computing systems that receive information about the surrounding environment from the laser radar system 100, analyze the received information, and provide control signals to the driving system of the vehicle (e.g., steering mechanism, accelerator, brake, light or turn signal). As an example, the laser radar system 100 integrated into the autonomous vehicle may provide a point cloud to the autonomous vehicle driving system every 0.1 seconds (e.g., the point cloud has an update rate of 10 Hz, indicating 10 frames per second). The autonomous vehicle driving system may analyze the received point cloud to sense or identify the target 130 and its corresponding position, distance or speed, and the autonomous vehicle driving system may update the control signal based on the information. As an example, if the laser radar system 100 detects a vehicle ahead that is slowing down or stopping, the autonomous vehicle driving system may send instructions to release the accelerator and apply the brakes.

[0119] In certain embodiments, an autonomous vehicle may be referred to as an autonomous car, a driverless car, an autonomous car, a robot car, or an unmanned vehicle. In certain embodiments, an autonomous vehicle may refer to a vehicle that is configured to sense its environment and navigate or drive with little or no human input. As an example, an autonomous vehicle may be configured to drive to any suitable location and control or perform all safety-critical functions (e.g., driving, steering, braking, parking) throughout the journey without the driver being expected to control the vehicle at any time. As another example, an autonomous vehicle may allow the driver to safely divert their attention from the driving task in a particular environment (e.g., on a highway), or an autonomous vehicle may provide control of the vehicle in all but a few environments with little or no input or attention from the driver.

[0120] In a particular embodiment, an autonomous vehicle may be configured to drive with a driver in the vehicle, or the autonomous vehicle may be configured to operate the vehicle without a driver. As an example, an autonomous vehicle may include a driver's seat with associated control devices (e.g., a steering wheel, an accelerator pedal, and a brake pedal), and the vehicle may be configured to drive without anyone sitting in the driver's seat or with little or no input from a person sitting in the driver's seat. As another example, an autonomous vehicle may not include any driver's seat or associated driver control devices, and the vehicle may perform almost all driving functions (e.g., driving, steering, braking, parking, and navigation) without manual input. As another example, an autonomous vehicle may be configured to operate without a driver (e.g., a vehicle may be configured to transport human passengers or cargo without a driver in the vehicle). As another example, an autonomous vehicle may be configured to operate without any human passengers (e.g., a vehicle may be configured to transport cargo without any human passengers on the vehicle).

[0121] In certain embodiments, the optical signal (which may be referred to as an optical signal, an optical waveform, an optical waveform, an output beam, an emitted optical signal, or an emitted light) may include optical pulses, CW light, amplitude modulated light, frequency modulated (FM) light, or any suitable combination thereof. Although the present disclosure describes or illustrates example embodiments of a laser radar system 100 or a light source 110 that generates an optical signal including optical pulses, the embodiments described or illustrated herein may also be applied to other types of optical signals, including continuous wave (CW) light, amplitude modulated optical signals, or frequency modulated optical signals, where appropriate. For example, the laser radar system 100 as described or illustrated herein may be a pulsed laser radar system and may include a light source 110 that generates optical pulses. Alternatively, the laser radar system 100 may be configured to operate as a frequency modulated continuous wave (FMCW) laser radar system and may include a light source 110 that generates CW light or a frequency modulated optical signal.

[0122] In certain embodiments, the lidar system 100 may be a FMCW lidar system, in which the emitted light from the light source 110 (eg, Figure 1 or Figure 3The output light beam 125 in the laser radar system 100 includes frequency modulated light. A pulse laser radar system is a type of laser radar system 100 in which the light source 110 emits light pulses and the distance to the remote target 130 is determined based on the round-trip flight time of the light pulses to travel to the target 130 and back. Another type of laser radar system 100 is a frequency modulated laser radar system, which may be referred to as a frequency modulated continuous wave (FMCW) laser radar system. An FMCW laser radar system uses frequency modulated light to determine the distance to the remote target 130 based on the frequency of the received light (including the emitted light scattered by the remote target) relative to the frequency of the local oscillator (LO) light. The round-trip time for the emitted light to travel to the target 130 and back to the laser radar system may correspond to the frequency difference between the received scattered light and the LO light. A larger frequency difference may correspond to a longer round-trip time and a larger distance to the target 130.

[0123] The light source 110 for the FMCW laser radar system may include at least one example: (i) a direct emitter laser diode, (ii) a seed laser diode followed by an SOA, (iii) a seed laser diode followed by a fiber amplifier, or (iv) a seed laser diode followed by an SOA and then a fiber amplifier. The seed laser diode or the direct emitter laser diode may be operated in a CW mode (e.g., by driving the laser diode with a substantially constant DC current), and the frequency modulation may be provided by an external modulator (e.g., an electro-optic phase modulator may apply frequency modulation to the seed laser). Alternatively, the frequency modulation may be generated by applying current modulation to the seed laser diode or the direct emitter laser diode. The current modulation (which may be provided together with the DC bias current) may generate a corresponding refractive index modulation in the laser diode, which results in a frequency modulation of the light emitted by the laser diode. The current modulation component (and the corresponding frequency modulation) may have any suitable frequency or shape (e.g., piecewise linear, sinusoidal, triangular, or sawtooth). For example, the current modulation component (and the resulting frequency modulation of the emitted light) may increase or decrease monotonically within a specific time interval. As another example, the current modulation component may include a triangular wave or a sawtooth wave having a current that increases or decreases linearly within a specific time interval, and the light emitted by the laser diode may include a corresponding frequency modulation, in which the optical frequency increases or decreases approximately linearly within the specific time interval. For example, a light source 110 that emits light with a linear frequency variation of 200 MHz within a 2 μs time interval may be referred to as having a frequency modulation of 10 14 Hz / s (or, 100MHz / μs) frequency modulation m.

[0124] In addition to generating frequency modulated emission light, the light source 110 may also generate frequency modulated local oscillator (LO) light. The LO light may be coherent with the emitted light, and the frequency modulation of the LO light may match the frequency modulation of the emitted light. The LO light may be generated by separating a portion of the emitted light before the emitted light leaves the lidar system. Alternatively, the LO light may be generated by a seed laser diode or a direct emitter laser diode as part of the light source 110. For example, the LO light may be emitted from the back of the seed laser diode or the direct emitter laser diode, or the LO light may be separated from the seed light emitted from the front of the seed laser diode. The received light (e.g., the emission light scattered by the target 130) and the LO light may each be frequency modulated with a frequency difference or offset corresponding to the distance to the target 130. For a linear chirped light source (e.g., a frequency modulation that generates a frequency that varies linearly with time), the greater the frequency difference between the received light and the LO light, the farther the target 130 is located.

[0125] The frequency difference between the received light and the LO light can be determined by mixing the received light with the LO light (e.g., by coupling the two light beams to a detector so that they are coherently mixed together at the detector) and determining the resulting beat frequency. For example, the photocurrent signal generated by the APD may include a beat frequency signal generated by the coherent mixing of the received light and the LO light, and the frequency of the beat frequency signal may correspond to the frequency difference between the received light and the LO light. The photocurrent signal from the APD (or a voltage signal corresponding to the photocurrent signal) can be analyzed using a frequency analysis technique (e.g., a fast Fourier transform (FFT) technique) to determine the frequency of the beat frequency signal. If a linear frequency modulation m (e.g., in units of Hz / s) is applied to the CW laser, the round-trip time T can be related to the frequency difference Δf between the received scattered light and the LO light by the expression T=Δf / m. In addition, the distance D from the target 130 to the lidar system 100 can be expressed as D=(Δf / m)·c / 2, where c is the speed of light. For example, for a laser radar system with 10 14 Hz / s linear frequency modulated light source 110, if a frequency difference of 33 MHz is measured (between the received scattered light and the LO light), this corresponds to a round trip time of approximately 330 ns and a distance to the target of approximately 50 meters. As another example, a frequency difference of 133 MHz corresponds to a round trip time of approximately 1.33 μs and a distance to the target of approximately 200 meters. A receiver or processor of the FMCW lidar system can determine the frequency difference between the received scattered light and the LO light, and can determine the distance to the target based on the frequency difference. The frequency difference Δf between the received scattered light and the LO light corresponds to the round trip time T (e.g., by the relationship T=Δf / m), and determining the frequency difference can correspond to or can be referred to as determining the round trip time.

[0126] Figure 2 An example scan pattern 200 generated by the lidar system 100 is shown. The scanner 120 of the lidar system 100 can scan the output beam 125 (which can include multiple emitted light signals) along the scan pattern 200 contained within the field of view (FOR) of the lidar system 100. The scan pattern 200 (which can be referred to as an optical scan pattern, an optical scan path, a scan path, or a scan) can represent the path or route followed by the output beam 125 as the output beam 125 scans across all or part of the FOR. Each traversal of the scan pattern 200 can correspond to the capture of a single frame or a single point cloud. In particular embodiments, the lidar system 100 can be configured to scan the output beam 125 along one or more particular scan patterns 200. In particular embodiments, the scan pattern 200 can span a region having any suitable horizontal FOR (FOR). H ) and any suitable vertical FOR(FOR V ). For example, the scanning pattern 200 may have an angular dimension of 40°×30°, 90°×40°, or 60°×15° (e.g., FOR H ×FOR V As another example, the scanning pattern 200 may have a FOR greater than or equal to 10°, 25°, 30°, 40°, 60°, 90°, or 120°. H As another example, the scanning pattern 200 may have a FOR greater than or equal to 2°, 5°, 10°, 15°, 20°, 30°, or 45°. V .

[0127] exist Figure 2 In the example of , reference line 220 represents the center of the field of view of scanning pattern 200. In certain embodiments, reference line 220 can have any suitable orientation, such as, for example, a horizontal angle of 0° (e.g., reference line 220 can be oriented straight ahead) and a vertical angle of 0° (e.g., reference line 220 can have an inclination of 0°), or reference line 220 can have a non-zero horizontal angle or a non-zero inclination (e.g., a vertical angle of +10° or -10°). Figure 2 In the embodiment, if the scanning pattern 200 has a field of view of 60°×15°, the scanning pattern 200 covers a horizontal range of ±30° relative to the reference line 220 and a vertical range of ±7.5° relative to the reference line 220. In addition, Figure 2The light beam 125 in FIG. 1 has an orientation of approximately -15° horizontal and +3° vertical relative to the reference line 220. The light beam 125 may be referred to as having an azimuth of -15° and an elevation of +3° relative to the reference line 220. In certain embodiments, the azimuth (which may be referred to as an azimuth angle) may represent a horizontal angle relative to the reference line 220, and the elevation (which may be referred to as an elevation angle, a tilt angle, or a tilt angle) may represent a vertical angle relative to the reference line 220.

[0128] In certain embodiments, the scan pattern 200 may include a plurality of pixels 210, and each pixel 210 may be associated with one or more laser pulses or one or more distance measurements. In addition, the scan pattern 200 may include a plurality of scan lines 230, wherein each scan line represents a scan across at least a portion of the field of view, and each scan line 230 may include a plurality of pixels 210. Figure 2 , as viewed from the lidar system 100, the scan line 230 includes five pixels 210 and corresponds to an approximately horizontal scan across FOR from right to left. In certain embodiments, a period of the scan pattern 200 may include a total of P x ×P y Pixel 210 (eg, P x Multiply P y The scanning pattern 200 may include a distribution having a size of approximately 100-2,000 pixels 210 in the horizontal direction and approximately 4-400 pixels 210 in the vertical direction. As another example, the scanning pattern 200 may include a distribution of 1,000 pixels 210 in the horizontal direction by 64 pixels 210 in the vertical direction (e.g., a frame size of 1000×64 pixels), with a total of 64,000 pixels per cycle of the scanning pattern 200. In certain embodiments, the number of pixels 210 in the horizontal direction may be referred to as the horizontal resolution of the scanning pattern 200, and the number of pixels 210 in the vertical direction may be referred to as the vertical resolution. As an example, the scanning pattern 200 may have a horizontal resolution greater than or equal to 100 pixels 210 and a vertical resolution greater than or equal to 4 pixels 210. As another example, the scan pattern 200 may have a horizontal resolution of 100-2000 pixels 210 and a vertical resolution of 4-400 pixels 210 .

[0129] In certain embodiments, a pixel 210 may refer to a pixel including (i) distance information (e.g., the distance from the laser radar system 100 to the target 130 from which the associated light pulse is scattered) or (ii) a tilt angle and an azimuth angle associated with the pixel (e.g., the tilt angle and the azimuth angle along which the associated light pulse is emitted). Each pixel 210 may be associated with a distance (e.g., the distance to a portion of the target 130 from which the associated laser pulse is scattered) or one or more angle values. As an example, a pixel 210 may be associated with a distance value and two angle values ​​(e.g., an azimuth and an elevation) representing the angular position of the pixel 210 relative to the laser radar system 100. The distance to a portion of the target 130 may be determined at least in part based on a time-of-flight measurement of the corresponding pulse. The angle value (e.g., an azimuth or an elevation) may correspond to an angle of the output beam 125 (e.g., relative to the reference line 220) (e.g., when the corresponding pulse is emitted from the laser radar system 100) or an angle of the input beam 135 (e.g., when the laser radar system 100 receives the input signal). In certain embodiments, the angle value may be determined based at least in part on the position of components of the scanner 120. As an example, an azimuth or elevation value associated with a pixel 210 may be determined from the angular position of one or more corresponding scanning mirrors of the scanner 120.

[0130] Figure 3 An example lidar system 100 is shown with an example rotating polygonal mirror 301. In certain embodiments, the scanner 120 may include a polygonal mirror 301 configured to scan the output beam 125 along a particular direction. Figure 3 Not shown in the figure, when outputting light pulses as part of the output light beam 125, the laser radar system 100 may include a pulse energy measurement circuit as disclosed herein for determining the pulse energy associated with a single output light pulse. Figure 3 In the example of FIG. 1 , the scanner 120 includes two scanning mirrors: (1) along θ x The polygon mirror 301 rotates in the direction of (2) along θ y The output beam 125 from the light source 110 (which passes by the reflector 115) is reflected by the reflective surface 321 of the scanning mirror 302, and then reflected by the reflective surface (e.g., surface 320A, 320B, 320C, or 320D) of the polygonal mirror 301. The scattered light from the target 130 is returned to the laser radar system 100 as the input beam 135. The input beam 135 is reflected from the polygonal mirror 301, the scanning mirror 302, and the reflector 115, which directs the input beam 135 through the focusing lens 330 and to the detector 340 of the receiver 140. Figure 3As shown in , scanning mirror 302 includes reflective surface 321, and reflector 115 includes reflective surface 322. Detector 340 can be a PN photodiode, a PIN photodiode, an APD, a SPAD, or any other suitable detector. Reflective surface 320 (which may be referred to as a reflective surface) may include a reflective metal coating (e.g., gold, silver, or aluminum) or a reflective dielectric coating, and reflective surface 320 may have any suitable reflectivity R at the operating wavelength of light source 110 (e.g., R is greater than or equal to 70%, 80%, 90%, 95%, 98%, or 99%).

[0131] In certain embodiments, the polygon mirror 301 may be configured to be x or Θ y The output beam 125 is rotated in the substantially horizontal or vertical direction. x The rotation of the direction may refer to the rotational movement of the mirror 301 that causes the output beam 125 to scan in a substantially horizontal direction. y Rotation in direction may refer to a rotational motion that causes the output beam 125 to scan in a substantially vertical direction. Figure 3 In the embodiment, the reflector 301 is along Θ x The polygon mirror rotates in the direction and scans the output beam 125 in a substantially horizontal direction, and the reflector 302 is rotated along θ y The polygon mirror 301 pivots in the substantially vertical direction and scans the output light beam 125 in a substantially vertical direction. In certain embodiments, the polygon mirror 301 can be configured to scan the output light beam 125 in any suitable direction. As an example, the polygon mirror 301 can scan the output light beam 125 at any suitable angle relative to the horizontal or vertical direction, such as, for example, at an angle of about 0°, 10°, 20°, 30°, 45°, 60°, 70°, 80°, or 90° relative to the horizontal or vertical direction.

[0132] In certain embodiments, the polygonal mirror 301 may refer to a multi-sided object having reflective surfaces 320 on two or more of its sides or faces. As an example, the polygonal mirror may include any suitable number of reflective faces (e.g., 2, 3, 4, 5, 6, 7, 8, or 10 faces), each of which includes a reflective surface 320. The polygonal mirror 301 may have any suitable polygonal cross-sectional shape, such as, for example, a triangle (having three reflective surfaces 320), a square (having four reflective surfaces 320), a pentagon (having five reflective surfaces 320), a hexagon (having six reflective surfaces 320), a heptagon (having seven reflective surfaces 320), or an octagon (having eight reflective surfaces 320). Figure 3 , the polygon mirror 301 has a substantially square cross-sectional shape and four reflecting surfaces (320A, 320B, 320C, and 320D). Figure 3The polygon mirror 301 in FIG. 301 may be referred to as a square mirror, a cubic mirror or a four-sided polygon mirror. Figure 3 In the embodiment, the polygon mirror 301 may have a shape similar to a cube, a cuboid or a right angle prism. In addition, the polygon mirror 301 may have a total of six sides, wherein four sides include faces having reflective surfaces (320A, 320B, 320C and 320D).

[0133] In certain embodiments, the polygon mirror 301 may be continuously rotated in a clockwise or counterclockwise direction about a rotation axis of the polygon mirror 301. The rotation axis may correspond to a line perpendicular to the rotation plane of the polygon mirror 301 and passing through the center of mass of the polygon mirror 301. Figure 3 , the polygon mirror 301 rotates in the plane of the figure, and the rotation axis of the polygon mirror 301 is perpendicular to the plane of the figure. The motor can be configured to rotate the polygon mirror 301 at a substantially fixed frequency (e.g., a rotation frequency of about 1 Hz (or 1 revolution per second), 10 Hz, 50 Hz, 100 Hz, 500 Hz, or 1000 Hz). As an example, the polygon mirror 301 can be mechanically coupled to a motor (e.g., a synchronous motor) that is configured to rotate the polygon mirror 301 at a rotation speed of about 160 Hz (or 9600 revolutions per minute (RPM)).

[0134] In certain embodiments, as the polygon mirror 301 rotates, the output beam 125 can be sequentially reflected from the reflective surfaces 320A, 320B, 320C, and 320D. This results in the output beam 125 being scanned along a particular scan axis (e.g., a horizontal or vertical scan axis) to generate a series of scan lines, where each scan line corresponds to a reflection of the output beam 125 from one of the reflective surfaces of the polygon mirror 301. Figure 3 , the output beam 125 reflects off of the reflective surface 320A to produce one scan line. Then, as the polygonal mirror 301 rotates, the output beam 125 reflects off of the reflective surfaces 320B, 320C, and 320D to produce second, third, and fourth corresponding scan lines. In certain embodiments, the lidar system 100 may be configured such that the output beam 125 is first reflected from the polygonal mirror 301 and then reflected from the scanning mirror 302 (or vice versa). As an example, the output beam 125 from the light source 110 may first be directed to the polygonal mirror 301, where it is reflected by the reflective surface of the polygonal mirror 301, and then the output beam 125 may be directed to the scanning mirror 302, where it is reflected by the reflective surface 321 of the scanning mirror 302. In Figure 3 In the example of FIG. 1 , the output beam 125 is reflected from the polygon mirror 301 and the scanning mirror 302 in reverse order. Figure 3In FIG. 1 , the output beam 125 from the light source 110 is first directed to the scanning mirror 302, where it is reflected by the reflective surface 321, and then the output beam 125 is directed to the polygonal mirror 301, where it is reflected by the reflective surface 320A.

[0135] Figure 4 An example light source field of view (FOV) of the laser radar system 100 is shown. L ) and the receiver field of view (FOV R ). The light source 110 of the laser radar system 100 can be adjusted with the FOV L and FOV R Light pulses are emitted by scanner 120 as they are scanned across a field of view (FOR). In certain embodiments, the source field of view may refer to the angular cone illuminated by light source 110 at a particular moment in time. Similarly, the receiver field of view may refer to the angular cone over which receiver 140 may receive or detect light at a particular moment in time, and any light outside the receiver field of view may not be received or detected. As an example, as the source field of view is scanned across the field of view, a portion of the light pulse emitted by light source 110 may be sent from lidar system 100 in the direction of emission, and the light pulse may be emitted within the FOV when the pulse is emitted. L The light pulses may be scattered off the target 130 and the receiver 140 may receive and detect the light pulses along the FOV R or included in FOV R Part of the scattered light within.

[0136] In certain embodiments, the scanner 120 may be configured to scan both the source field of view and the receiver field of view across the field of view of the lidar system 100. As the scanner 120 scans the FOV across the field of view of the lidar system 100 while tracing out the scan pattern 200 L and FOV R , multiple light pulses can be emitted and detected. In certain embodiments, the light source field of view and the receiver field of view can be scanned synchronously relative to each other so that as the FOV L The scanning pattern is scanned across 200, FOV R At the same scanning speed, the FOV L and FOV R can maintain the same relative position to each other as they are scanned across the field of view. As an example, FOV L Can be with FOV R Basically overlap or center the FOV R (like Figure 4 ), and the FOV can be maintained throughout the scan L and FOV R As another example, FOVR Can lag behind FOV throughout the scan L A specific fixed quantity (e.g., FOV R Can deviate FOV in the direction opposite to the scanning direction L ).

[0137] In certain embodiments, FOV L The angular size or range θ may be substantially the same as or corresponding to the divergence angle of the output beam 125. L , and FOV R may have an angular size or range θ corresponding to the angle at which the receiver 140 may receive and detect light. R In certain embodiments, the receiver field of view can be any suitable size relative to the light source field of view. As an example, the receiver field of view can be less than, substantially equal to, or greater than the angular extent of the light source field of view. In certain embodiments, the light source field of view can have an angular extent less than or equal to 50 milliradians, and the receiver field of view can have an angular extent less than or equal to 50 milliradians. FOV L Can have any suitable angle range θ L , such as, for example, about 0.1 mrad, 0.2 mrad, 0.5 mrad, 1 mrad, 1.5 mrad, 2 mrad, 3 mrad, 5 mrad, 10 mrad, 20 mrad, 40 mrad, or 50 mrad. Similarly, FOV R Can have any suitable angle range θ R , such as, for example, about 0.1 mrad, 0.2 mrad, 0.5 mrad, 1 mrad, 1.5 mrad, 2 mrad, 3 mrad, 5 mrad, 10 mrad, 20 mrad, 40 mrad, or 50 mrad. In certain embodiments, the light source field of view and the receiver field of view may have approximately equal angular ranges. As an example, θ L and θ R Both can be approximately equal to 1 mrad, 2 mrad, or 4 mrad. In certain embodiments, the receiver field of view can be larger than the light source field of view, or the light source field of view can be larger than the receiver field of view. As an example, θ L can be approximately equal to 3mrad, and Θ R can be approximately equal to 4 mrad. As another example, θ R Can be compared to Θ L Approximately L times, where L is any suitable factor, such as, for example, 1.1, 1.2, 1.5, 2, 3, 5 or 10.

[0138] In certain embodiments, pixel 210 may represent or correspond to a light source field of view or a receiver field of view. As output beam 125 propagates from light source 110, the diameter of output beam 125 (and the size of corresponding pixel 210) may be determined based on beam divergence angle θ. L As an example, if the output beam 125 has a θ of 2 mrad L , then at a distance of 100 m from the laser radar system 100, the output beam 125 may have a size or diameter of approximately 20 cm, and the corresponding pixel 210 may also have a corresponding size or diameter of approximately 20 cm. At a distance of 200 m from the laser radar system 100, the output beam 125 and the corresponding pixel 210 may each have a diameter of approximately 40 cm.

[0139] Figure 5 An example unidirectional scan pattern 200 is shown including a plurality of pixels 210 and a plurality of scan lines 230. In particular embodiments, the scan pattern 200 may include any suitable number of scan lines 230 (e.g., approximately 1, 2, 5, 10, 20, 50, 100, 500, or 1000 scan lines), and each scan line 230 of the scan pattern 200 may include any suitable number of pixels 210 (e.g., 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, or 5000 pixels). Figure 5 The scanning pattern 200 shown in FIG. 1 includes eight scanning lines 230, and each scanning line 230 includes about 16 pixels 210. In certain embodiments, a scanning pattern 200 that scans the scanning lines 230 in two directions (e.g., alternately scanning from right to left and then from left to right) may be referred to as a bidirectional scanning pattern 200, and a scanning pattern 200 that scans the scanning lines 230 in the same direction may be referred to as a unidirectional scanning pattern 200. Figure 2 The scanning pattern 200 in FIG. 2 may be referred to as a bidirectional scanning pattern, and Figure 5 The scanning pattern 200 in the unidirectional scanning pattern 200 may be referred to as a unidirectional scanning pattern 200, wherein each scan line 230 travels across the FOR in substantially the same direction (e.g., approximately from left to right as viewed from the lidar system 100). In certain embodiments, the scan lines 230 of the unidirectional scanning pattern 200 may be directed across the FOR in any suitable direction, such as, for example, from left to right, from right to left, from top to bottom, from bottom to top, or at any suitable angle relative to the horizontal axis or the vertical axis (e.g., at an angle of 0°, 5°, 10°, 30°, or 45°). In certain embodiments, each scan line 230 in the unidirectional scanning pattern 200 may be a separate line that is not directly connected to the previous or next scan line 230.

[0140] In certain embodiments, the unidirectional scanning pattern 200 may be formed by a multi-faceted mirror (eg, Figure 3The scan line 230 is generated by a scanner 120 with a polygon mirror 301, wherein each scan line 230 is associated with a specific reflective surface 320 of the polygon mirror. As an example, Figure 3 The reflective surface 320A of the polygon mirror 301 can produce Figure 5 230A in the unidirectional scanning pattern 200. Similarly, as the polygonal mirror 301 rotates, the reflective surfaces 320B, 320C, and 320D can continuously generate scan lines 230B, 230C, and 230D, respectively. In addition, for subsequent rotations of the polygonal mirror 301, scan lines 230A', 230B', 230C', and 230D' can be continuously generated by reflections of the output light beams 125 from the reflective surfaces 320A, 320B, 320C, and 320D, respectively. In a particular embodiment, the N consecutive scan lines 230 of the unidirectional scanning pattern 200 may correspond to one full revolution of the N-faceted polygonal mirror. As an example, Figure 5 The four scan lines 230A, 230B, 230C and 230D in Figure 3 In addition, the subsequent rotation of the polygon mirror 301 can produce Figure 5 The next four scan lines 230A', 230B', 230C' and 230D'.

[0141] Figure 6 An example light source, a beam splitter, and a pulse energy measurement circuit are shown. In the example shown, Figure 6 Including integration into LiDAR systems such as Figure 1-4 The components of the laser radar system 100 of FIG. 1 include a light source 110, a beam splitter 470, and a pulse energy circuit 600 for performing pulse energy measurement. For example, at least in part using Figure 6 Components and a processor and / or controller of the laser radar system can measure a single light pulse output by the corresponding laser radar system for its corresponding pulse energy. In some embodiments, the light source 110 is Figure 1 and / or Figure 3 The light source 110, and the output light beam 125 is Figure 1-4 The output beam 125.

[0142] like Figure 6In the example shown in , the light source 110 outputs an emission light beam 124. In a specific application of the light source 110, the emission light beam 124 outputs light pulses as emission pulses 400. The beam splitter 470 receives the emission light beam 124 and splits the beam into an output light beam 125 and a test light beam 126. The output light beam 125 includes an output pulse 401 and the test light beam 126 includes a test pulse 402. In various embodiments, the beam splitter 470 is configured to split the emission light beam 124 into the output light beam 125 and the test light beam 126 according to a specific splitting ratio. Once the emission light beam 124 is split by the beam splitter 470, the test light beam 126 is received at the pulse energy circuit 600, and the output light beam 125 is directed toward other components of the lidar system, such as Figure 1 Scanner 120. In various embodiments, pulse energy circuit 600 receives test beam 126 as test pulse 402. Pulse energy circuit 600 is a pulse energy measurement module and includes a pulse energy measurement circuit for determining, at least in part, a single pulse energy of test pulse 402. Pulse energy circuit 600 can output one or more numerical values ​​corresponding to the energy of test pulse 402. In various embodiments, the pulse energy of test pulse 402 corresponds to the pulse energy of output pulse 401 and is used to determine the pulse energy of output pulse 401. For example, using term (E O ) is represented by the energy of the output pulse 401 expressed by E O =E T / f confirm, where E T is the energy of the test pulse 402, and f is the splitting ratio of the beam splitter 470. In various embodiments, the beam splitter 470 may be such as Figure 7 The free space beam splitter 4 shown in Figure 8 The optical fiber splitter shown in , and / or another suitable splitter 4 that satisfies the required splitting ratio.

[0143] In some embodiments, beam splitter 470 is a beam splitter and is configured to split emitted light beam 124 so that the energies of test pulse 402 and output pulse 401 meet specific energy requirements relative to emitted pulse 400. For example, in some embodiments, emitted light beam 124 is split so that the energy of test pulse 402 is less than or equal to 2% of the energy of emitted pulse 400, and the energy of output pulse 401 is greater than or equal to 98% of the energy of emitted pulse 400. In some embodiments, beam splitter 470 is a free space beam splitter, an integrated beam splitter, a fiber beam splitter, or another suitable type of beam splitter capable of meeting specific energy requirements when splitting emitted light beam 124.

[0144] Figure 7 An example free space beam splitter is shown. In the example shown, the free space beam splitter 470 is Figure 6 An example embodiment of the optical splitter 470. Figure 7 As shown in FIG. 4 , a free space beam splitter 470 splits the emission beam 124 into an output beam 125 and a test beam 126. In various embodiments, the emission beam 124, the output beam 125, and the test beam 126 may be optical pulses, such as from Figure 1 , Figure 3 and / or Figure 6 In various embodiments, the test beam 126 is directed to a pulse energy circuit such as Figure 6 Pulse energy circuit 600. In certain embodiments, free space beam splitter 470 may be implemented using one or more prisms and / or mirrors.

[0145] Figure 8 An example fiber optic splitter is shown. In the example shown, the fiber optic splitter 470 is Figure 6 Example fiber optic embodiment of the optical splitter 470. Figure 8 As shown in FIG. 4 , the fiber optic splitter 470 includes an input fiber 502a, an output fiber 502b, an output fiber 502c, and a collimator 542. In the case of the fiber optic splitter 470, the emitted light beam 124 is transmitted via the input fiber 502a and split between the output fiber 502b and the output fiber 502c. The output fiber 502b is connected to the collimator 542, which outputs the received light beam as the output light beam 125. The output fiber 502c transmits the split portion of the emitted light beam 124 as the test light beam 126. In various embodiments, the test light beam 126 is directed to a pulse energy circuit, such as Figure 6 In various embodiments, the emitted light beam 124, the output light beam 125, and the test light beam 126 may be light pulses, such as from Figure 1 , Figure 3 and / or Figure 6 The light source 110 generates light pulses.

[0146] Fig. 9 An example light source, a beam splitter, and a pulse energy measurement circuit are shown, where the light source includes a seed laser diode and a semiconductor optical amplifier (SOA). In the example shown, Fig. 9An embodiment of a light source 110 is included, which includes a seed laser diode 450, a semiconductor optical amplifier (SOA) 460, and an electronic driver 480. In various embodiments, the electronic driver 480 at least partially provides a seed current I1 to the seed laser diode 450 and provides a semiconductor optical amplifier (SOA) current I2 to the semiconductor optical amplifier (SOA) 460 to generate an emitted light beam 124. Within the light source 110, the seed laser diode 450 outputs a seed light 440, which is amplified by the semiconductor optical amplifier (SOA) 460. The light source 110 outputs the emitted light beam 124 to a beam splitter 470. The beam splitter 470 splits the emitted light beam 124 into an output beam 125 and a test beam 126. The test beam 126 is directed to a pulse energy circuit 600. As shown in FIG. Fig. 9 As shown in FIG. 1 , the emitted light beam 124, the output light beam 125, and the test light beam 126 include corresponding light pulse emission pulses 400, output pulses 401, and test pulses 402, respectively. In various embodiments, Fig. 9 components into the LiDAR system, such as Figure 1-4 The laser radar system 100 is used to perform pulse energy measurement, and the light source 110 is Figure 1 , Figure 3 and / or Figure 6 The light source 110, and the output light beam 125 is Figure 1-4 and Figure 6-8 The output beam 125. In some embodiments, the beam splitter 470 is Figure 6 , Figure 7 and / or Figure 8 The optical splitter 470 and the pulse energy circuit 600 are Figure 6 Similarly, the emitted light beam 124 and the emitted pulse 400 are Figure 6 The emitted light beam 124 and emitted pulse 400, the output light beam 125 and output pulse 401 are Figure 6 The output beam 125 and the output pulse 401, and the test beam 126 and the test pulse 402 are Figure 6 The test beam 126 and the test pulse 402 are shown.

[0147] exist Fig. 9 In the example of FIG. 4 , the light source 110 includes a seed laser diode 450 and a semiconductor optical amplifier (SOA) 460, which are driven by an electronic driver 480 to generate light pulses, such as the emitted pulse 400. Figure 6As described, the emitted pulse 400 is split by the beam splitter 470 to produce a test pulse 402 that can be measured by the pulse energy circuit 600. In some embodiments, the pulse energy circuit 600 outputs a numerical value corresponding to the energy of the test pulse 402. The processor and / or controller of the laser radar system determines the amount of single pulse energy of the test pulse 402 based on the determined numerical value provided by the pulse energy circuit 600. The pulse energy of the output pulse 401 can also be determined by the relationship between the output pulse 401 and the test pulse 402. In various embodiments, the output pulse measurement can be used to modify the operating parameters of the light source 110, such as powering on or off the light source 110 and / or its components.

[0148] Fig.10 An example light source, a beam splitter, and a pulse energy measurement circuit are shown, where the light source includes a seed laser diode, a semiconductor optical amplifier (SOA), and a fiber amplifier. Fig.10 An example similar to Fig. 9 , but shows a different embodiment of the light source 110. In the example shown, Fig.10 An embodiment includes a light source 110, which includes a seed laser diode 450, a semiconductor optical amplifier (SOA) 460, and a fiber amplifier 500. In the light source 110, the seed laser diode 450 outputs a seed light 440, which is amplified by the semiconductor optical amplifier (SOA) 460 into a light pulse 400a amplified by the SOA. The fiber amplifier 500 amplifies the light pulse 400a amplified by the SOA, and thus the light source 110 outputs an emitted light beam 124 including the emitted pulse 400 to the beam splitter 470. The beam splitter 470 divides the emitted light beam 124 into an output light beam 125 and a test light beam 126. The test light beam 126 is guided to the pulse energy circuit 600. Similar to Fig. 9 For example, Fig.10 In the embodiment, the emitted light beam 124, the output light beam 125 and the test light beam 126 respectively include corresponding light pulse emission pulses 400, output pulses 401 and test pulses 402. In various embodiments, Fig.10 components into the LiDAR system, such as Figure 1-4 The laser radar system 100 is used to perform pulse energy measurement, and the light source 110 is Figure 1 , Figure 3 and / or Figure 6 The light source 110, and the output light beam 125 is Figure 1-4 and Figure 6-8 The output beam 125. In some embodiments, the beam splitter 470 is Figure 6 , Figure 7 and / or Figure 8 The optical splitter 470 and the pulse energy circuit 600 are Figure 6Similarly, the emitted light beam 124 and the emitted pulse 400 are Figure 6 The emitted light beam 124 and emitted pulse 400, the output light beam 125 and output pulse 401 are Figure 6 The output beam 125 and the output pulse 401, and the test beam 126 and the test pulse 402 are Figure 6 The test beam 126 and the test pulse 402 are shown.

[0149] exist Fig.10 In the example of FIG. 4 , the light source 110 includes a seed laser diode 450, a semiconductor optical amplifier (SOA) 460, and a fiber amplifier 500 to generate light pulses, such as the emitted pulse 400. Figure 6 and Fig. 9 As described, the emitted pulse 400 is split by the beam splitter 470 to produce a test pulse 402 that can be measured by the pulse energy circuit 600. In some embodiments, the pulse energy circuit 600 outputs a numerical value corresponding to the energy of the test pulse 402. The processor and / or controller of the laser radar system determines the amount of single pulse energy of the test pulse 402 based on the determined numerical value provided by the pulse energy circuit 600. The pulse energy of the output pulse 401 can also be determined by the relationship between the output pulse 401 and the test pulse 402. In various embodiments, the output pulse measurement can be used to modify the operating parameters of the light source 110, such as powering on or off the light source 110 and / or its components.

[0150] Fig.11 An example fiber amplifier is shown. In various embodiments, Fig.11 The embodiment of the fiber amplifier 500 shown in FIG. 1 can be used as a fiber amplifier in a light source of a laser radar system. For example, in some embodiments, the fiber amplifier 500 is Fig.10 In the example shown, the fiber amplifier 500 includes input and output isolators 530, a gain fiber 501, a pump laser 510, and a pump WDM 520. The fiber amplifier 500 receives an optical pulse 400a, such as Fig.10 The SOA amplifies the optical pulse 400a and outputs the emitted light beam 124, which includes the emitted pulse 400. The emitted pulse 400 is generated by amplifying the optical pulse 400a using the optical fiber amplifier 500 and is directed to the optical splitter 470. The optical splitter 470 divides the emitted light beam 124 into an output light beam 125 and a test light beam 126. The test light beam 126 is directed to the pulse energy circuit 600. Similar to Fig. 9 and Fig.10 For example, Fig.11, the emitted light beam 124, the output light beam 125, and the test light beam 126 include corresponding light pulses, the emission pulse 400, the output pulse 401, and the test pulse 402, respectively. In the example shown, the fiber optic system includes an output collimator 570 to guide and / or narrow the output light beam 125. In various embodiments, Fig.11 components into the LiDAR system, such as Figure 1-4 The laser radar system 100 is used to perform pulse energy measurement, and the output beam 125 is Figure 1-4 , Figure 6-8 and / or Fig.10 The output beam 125. In some embodiments, the beam splitter 470 is Figure 6-8 and / or Fig.10 The optical splitter 470 and the pulse energy circuit 600 are Figure 6 and / or Fig.10 Similarly, the emitted light beam 124 and the emitted pulse 400 are Figure 6 and / or Fig.10 The emitted light beam 124 and emitted pulse 400, the output light beam 125 and output pulse 401 are Figure 6 and / or Fig.10 The output beam 125 and the output pulse 401, and the test beam 126 and the test pulse 402 are Figure 6 and / or Fig.10 The test beam 126 and the test pulse 402 are shown.

[0151] In some embodiments, the energy of one or more instances of the test pulse 402 may be determined to be below a specific operating energy. In response to determining that the energy of the one or more test pulses is below the specific operating energy, an instruction is sent to the light source to increase the energy of the emitted light pulses. In some embodiments, increasing the energy of the emitted light pulses includes increasing the current provided to the pump laser 510 to increase the optical gain of the fiber amplifier 500. In some embodiments, the pump laser 510 is a pump laser diode.

[0152] Fig.12 An example pulse energy measurement circuit including a peak hold circuit and an analog-to-digital converter (ADC) is shown. In various embodiments, the pulse energy measurement circuit 600 is integrated into a laser radar system, such as Figure 1-4 The laser radar system 100 is configured to perform pulse energy measurement. For example, using the pulse energy measurement circuit 600, a single optical pulse can be measured for its corresponding pulse energy. In some embodiments, the optical pulse measured by the pulse energy measurement circuit 600 is obtained from a laser beam such as a laser beam. Figure 1 , Figure 3 , Figure 6 , Fig. 9 and / or Fig.10The test pulse is split from the light pulse generated by the light source 110 of the light source. In the example shown, the pulse energy measurement circuit 600 receives the test light pulse 402 and generates an output signal 682. In various embodiments, the output signal 682 encodes a numerical value corresponding to the pulse energy of the test light pulse 402. Fig.12 As shown in FIG. 6 , the pulse energy measurement circuit 600 includes at least a component detector 610, a transimpedance amplifier (TIA) 620, a peak hold circuit 630, a buffer amplifier 640, an analog-to-digital converter (ADC) 650, a threshold detector 660, a reset timer 670, and a timer 671. An embodiment of the peak hold circuit 630 is shown in detail using an enlarged view, which includes an amplifier U1, a diode D1, a capacitor C1, and a switch SW1. Fig.12 , waveforms corresponding to different signals are shown as a function of time t as they pass through the pulse energy measurement circuit 600. In some embodiments, the pulse energy measurement circuit 600 is Figure 6 , Fig. 9 , Fig.10 and / or Fig.11 The pulse energy circuit 600, and the test light pulse 402 is Figure 6 , Fig. 9 , Fig.10 and / or Fig.11 A test pulse 402 is provided.

[0153] exist Fig.12In an example embodiment of the invention, a detector 610 receives a test light pulse 402. The test light pulse 402 may be a portion of a light beam generated by a light source, which is divided into a test light pulse 402 and an output pulse. The detector 610 detects the test light pulse 402 and generates a corresponding photocurrent pulse. A transimpedance amplifier (TIA) 620 receives the photocurrent pulse and generates a corresponding voltage pulse. A peak hold circuit 630 receives the voltage pulse and generates a voltage signal corresponding to a currently detected peak voltage of the received voltage pulse. In various embodiments, the peak hold circuit 630 may be implemented using a detailed view shown in dashed outline. Based on the currently detected peak voltage signal, the peak hold circuit 630 outputs a peak hold voltage signal to a buffer amplifier 640. The buffer amplifier 640 buffers the received voltage signal and outputs a buffered peak hold voltage signal. The buffered peak hold voltage signal corresponds to the currently detected voltage peak of the test light pulse 402 and is sent to an analog-to-digital converter (ADC) 650 and a threshold detector 660. For example, the buffer amplifier 640 receives a voltage signal corresponding to the peak value of the voltage pulse associated with the test light pulse 402 from the peak hold circuit 630, and generates an output voltage signal corresponding to the received voltage signal. The ADC 650 converts the received analog signal to generate an output signal 682. In various embodiments, the output signal 682 is a digital output signal having a numerical value corresponding to the energy of the test light pulse 402, and is determined based on the received buffered voltage signal corresponding to the peak value of the voltage pulse. In the example shown, the ADC 650 also receives a trigger signal 662 as an input signal. The trigger signal 662 is an input trigger of the ADC 650, which, when activated, starts the ADC 650 to generate a valid output signal 682 corresponding to the energy of the test light pulse 402. In various embodiments, the processor and / or controller of the laser radar system determines the amount of single pulse energy of the test light pulse 402 based on the numerical value corresponding to the energy of the test light pulse 402 provided via the output signal 682.

[0154] In various embodiments, the threshold detector 660 sends a trigger signal 662 based on the received buffered peak hold voltage signal provided by the buffer amplifier 640. In a particular embodiment, the trigger signal 662 is sent when the received buffered peak hold voltage signal exceeds or rises to a particular threshold voltage value V T When the threshold value is above , the threshold detector 660 starts the operation of the ADC 650 via the trigger signal 662. Fig.12 As shown in the top rightmost waveform, the threshold voltage value V T Corresponding to V S The peak voltage of the pulse begins at the threshold voltage V TThe associated time triggers ADC 650, which is enabled to determine and output a numerical value corresponding to the amount of energy of test light pulse 402. In some embodiments, the amount of energy is based on when test light pulse 402 reaches the energy at time T S The corresponding peak value V T For example, in the case where the pulse energy measurement circuit 600 detects a test light pulse, the output signal 682 is proportional to the peak voltage (shown as V S ) is encoded. In some embodiments, the value is the peak voltage (V S ), the power associated with the test pulse and / or the energy associated with the test pulse. In some embodiments, V S The buffered peak hold voltage signal corresponds to the voltage peak of the test light pulse 402. In some embodiments, the value encoded by the output signal 682 is based on the peak voltage (V S ), and the encoded numerical value is used by a processor and / or controller of the lidar system to determine the amount of single pulse energy of the test light pulse 402.

[0155] In addition to sending the trigger signal 662 to the ADC 650, the threshold detector 660 also sends a trigger signal 662 to the reset timer 670 and the timer 671 to start their respective functions. In some embodiments, the reset timer 670 starts a timer that resets the peak hold circuit 630 when the timer expires. For example, the reset timer 670 sends a reset signal 672 to the peak hold circuit 630 to reset the peak voltage held by the peak hold circuit 630. In various embodiments, the reset timer 670 is configured to send the reset signal 672 based on an expected timing associated with the light pulse received by the pulse energy measurement circuit 600. For example, the reset timer 670 can be configured to provide the reset signal 672 to the peak hold circuit 630 at a specific time interval after the threshold detector 660 generates the trigger signal 662. In some embodiments, the timer of the reset timer 670 can be configured based on a time associated with the pulse width of the test light pulse 402. In some embodiments, the reset timer 670 is implemented by detecting a falling edge or end of the light pulse. For example, threshold detector 660 may detect both rising and falling edges of light pulses and send corresponding trigger signals to ADC 650 , reset timer 670 , and / or timer 671 based on the appropriate detected edges.

[0156] In some embodiments, the timer 671 receives a trigger signal 662 from the threshold detector 660 to start outputting a time value or timestamp. For example, the timer 671 can be configured to determine the reception time associated with the test light pulse 402 by outputting the corresponding reception time when the threshold detector 660 sends the trigger signal 662. In various embodiments, the output reception time corresponds to the numerical value encoded by the output signal 682. Although Fig.12 Not shown, timer 671 (and Fig.12 Other components of the system) may include additional connections, such as for sending an output signal of the time reception. In some embodiments, the time reception is sent to a device such as Figure 1 The controller 150 is a controller unit.

[0157] As along Fig.12 , four waveform graphs depict different signals generated by different components of the pulse energy measurement circuit 600. The waveform graphs (from left to right) show the output of the detector 610 as a pulse of the photocurrent waveform 403, the output of the TIA 620 as a voltage pulse waveform 404, the output of the peak hold circuit 630 as a peak hold voltage signal waveform 405, and the output of the buffer amplifier 640 as a buffered peak hold voltage signal waveform 406.

[0158] exist Fig.12 , an embodiment of the peak hold circuit 630 is shown in detail in the lower left corner of FIG. The detailed embodiment shows that the peak hold circuit 630 receives a voltage pulse (i.e., a voltage pulse corresponding to the voltage pulse waveform 404) as an input and generates a voltage signal corresponding to the peak value of the received voltage pulse (i.e., the peak hold voltage signal waveform 405). The peak hold circuit 630 also receives a reset signal 672 from the reset timer 670 as an input. When the reset signal 672 is received, the switch SW1 is closed until the energy held at the capacitor C1 is released. By closing the switch SW1, the peak hold voltage held by the peak hold circuit 630 is reset.

[0159] Fig.13 An example pulse energy measurement circuit including a plurality of comparators and a time-to-digital converter (TDC) is shown. In some embodiments, the pulse energy measurement circuit 600 is Figure 6 , Fig. 9 , Fig.10 and / or Fig.11 The pulse energy circuit 600 is similar to a laser radar receiver (such as Figure 1 and / or Figure 3140) of the receiver. In the example shown, the pulse energy measurement circuit 600 receives the test light pulse 402 and generates an output signal 682. In various embodiments, the output signal 682 corresponds to the pulse energy of the test light pulse 402. In various embodiments, the voltage pulse 404 and the received test light pulse 402 have similar rise time, fall time, shape, duration or other similar pulse characteristics. In a specific embodiment, the pulse energy measurement circuit 600 includes a detector 610, a transimpedance amplifier (TIA) 620, a plurality of comparators 680 and a plurality of time-to-digital converters (TDCs) 690. The detector 610 is configured to receive the test light pulse 402 and generate a photocurrent pulse 403 corresponding to the test light pulse 402. The TIA 620 is an electronic amplifier and generates a voltage pulse 404 corresponding to the pulse of the photocurrent 403, which is sent to a plurality of comparators 680 and a plurality of TDCs 690. The generated output signal 682 encodes a numerical value corresponding to the pulse energy of the test light pulse 402. In various embodiments, the value is determined based on one or more time values ​​generated by one or more TDCs 690 in the plurality of TDCs 690. In some embodiments, the pulse energy measurement circuit 600 is Figure 6 , Fig. 9 , Fig.10 and / or Fig.11 The pulse energy circuit 600, and the test light pulse 402 is Figure 6 , Fig. 9 , Fig.10 and / or Fig.11 A test pulse 402 is provided.

[0160] exist Fig.13 In the embodiment, the voltage pulse 404 generated by the TIA 620 is coupled to N comparators (comparator 680-1, 680-2, ..., 680-N), and each comparator is set with a specific threshold voltage (V T1 ,V T2 ,…,V TN ). The pulse energy measurement circuit 600 may include 1, 2, 5, 10, 50, 100, 500, 1000 or any other suitable number of comparators 680, and each comparator 680 may be set with a different threshold voltage. For example, Fig.13 The pulse energy measurement circuit 600 in FIG. 5 may include N=10 comparators, and the threshold voltage may be set to 10 values ​​between 0V and 1V (eg, V T1 =0.1V, V T2 =0.2V and V T10=1.0V). Each comparator can generate an electrical edge signal (e.g., a rising or falling electrical edge) when the voltage pulse 404 rises above a specific threshold voltage or falls below a specific threshold voltage. For example, when the voltage pulse 404 rises above the threshold voltage V T2 When the voltage pulse 404 drops below the threshold voltage V T2 When t′2 is reached, comparator 680 - 2 may generate a falling edge (at time t′2).

[0161] Fig.13 The pulse energy measurement circuit 600 in EMBODIMENT 1 includes N time-to-digital converters (TDCs 690 - 1 , 690 - 2 , . . . , 690 -N), and each comparator 680 is coupled to a TDC 690 . Fig.13 Each comparator-TDC pair in (e.g., comparator 680-1 and TDC 690-1) can be referred to as a threshold detector. The comparator can provide an electrical edge signal to the corresponding TDC, and the TDC can act as a timer that generates an electrical output signal representing the time when the edge signal is received from the comparator. For example, when voltage pulse 404 rises above threshold voltage V at time t1, T1 When the comparator 680-1 generates a rising edge signal provided to the input of the TDC 690-1, and the TDC 690-1 generates a digital time value corresponding to the time t1. In addition, when the voltage pulse 404 subsequently falls below the threshold voltage V at time t′1, T1 When t′1 is reached, comparator 680-1 may generate a falling edge signal that is provided to the input of TDC 690-1, and TDC 690-1 may generate another digital time value corresponding to time t′1. The digital time value may be referenced by a clock such as Figure 1 , Figure 3 , Figure 6 , Fig. 9 and / or Fig.10 The time when the light source 110 of the light source emits the test light pulse 402, and the one or more digital time values ​​can correspond to or can be used to at least partially determine the time when the laser radar system (such as Figure 1-4 The pulse energy corresponding to the test light pulse 402 of the laser radar system 100).

[0162] In certain embodiments, the output signal 682 of the pulse energy measurement circuit 600 may include an electrical signal corresponding to the received test light pulse 402. For example, Fig.13The output signal 682 in may be a digital signal corresponding to the analog voltage pulse 404, which in turn corresponds to the photocurrent 403, which in turn corresponds to the received test light pulse 402. The output signal 682 may further include one or more digital time values ​​from each of the TDCs 690 that receive one or more edge signals from the comparator 680, and the digital time values ​​may represent the analog voltage pulse 404. For example, TDC 690-1 may provide two digital time values ​​(corresponding to time t1 and t′1) as part of the output signal 682. Similarly, TDC 690-2 may provide two digital time values ​​(corresponding to time t2 and t′2), and TDC 690-3 may provide two digital time values ​​(corresponding to time t3 and t′3). The output signal 682 from the pulse energy measurement circuit 600 may be sent to a controller, such as Figure 1 The controller 150 of the embodiment of the present invention can be configured to receive the received test light pulse 402, and the arrival time of the received test light pulse 402 (which can be referred to as the reception time of the received test light pulse) can be determined at least in part based on the time value generated by the TDC. For example, the arrival time can be determined from the peak value of the voltage pulse 404 (e.g., V peak ), a time center (e.g., a centroid or a weighted average), or the time associated with a rising edge or a falling edge.

[0163] In some embodiments, Fig.13The output signal 682 in the pulse energy measurement circuit 600 may include a digital value for each TDC from the TDC that receives the edge signal from the comparator, and each digital value may represent a time interval between the light source 110 emitting a light pulse and receiving the edge signal from the comparator. For example, the light source 110 (not shown) may emit a light pulse that is divided into a test pulse and an output pulse. The test pulse may be received by the pulse energy measurement circuit 600 and corresponds to the input test light pulse 402. When the light source emits a light pulse, the count value of the TDC may be reset to a zero count, and the digital value generated by the TDC 690 may represent the amount of time that has passed since the light pulse was emitted. Alternatively, the TDC in the pulse energy measurement circuit 600 may continuously accumulate counts over a plurality of pulse cycles (e.g., 10, 100, 1,000, 10,000, or 100,000 pulse cycles), and when a light pulse is emitted, instead of resetting the TDC count value to a zero count, the TDC count associated with the time when the pulse was emitted may be stored in a memory. After the light pulse is emitted, the TDC may continue to accumulate counts corresponding to the elapsed time without resetting the TDC count value to a zero count. In this case, the digital value generated by the TDC 690 may represent the count value when the edge signal was received by the TDC 690. Additionally, the amount of time that has elapsed since the light pulse was emitted may be determined by subtracting the count value associated with the emission of the light pulse from the count value of the edge signal associated with the received test light pulse 402.

[0164] In some embodiments, when the TDC 690-1 receives an edge signal from the comparator 680-1, the TDC 690-1 may generate a digital signal representing the time interval between the emission of the test light pulse 402 and the receipt of the edge signal. For example, the digital signal may include a digital value corresponding to the number of clock cycles that have passed between the emission of the test light pulse and the receipt of the edge signal. Alternatively, if the TDC 690-1 accumulates counts over multiple pulse cycles, the digital signal may include a digital value corresponding to the TDC count when the edge signal is received. The output signal 682 may include digital values ​​corresponding to one or more times the test light pulse is emitted and one or more times the TDC receives the edge signal. The output signal 682 from the pulse energy measurement circuit 600 may correspond to the received light pulse and may include a digital value from each of the TDCs that received the edge signal from the comparator. The output signal 682 may be sent to a controller, such as Figure 1The controller 150 of the embodiment of the present invention can be used to determine whether the associated lidar system is operating normally based at least in part on the output signal 682. In addition or alternatively, the controller can determine the optical characteristics of the test light pulse 402 based at least in part on the output signal 682 received from the TDC of the pulse energy measurement circuit 600. The optical characteristics of the received light pulse can include peak light intensity, peak light power, average light power, light energy, shape or amplitude, arrival time, time center, round-trip flight time, rise time, fall time, or time duration or width of the received light pulse.

[0165] In some embodiments, Fig.13 The example voltage pulse 404 shown in FIG. 4 corresponds to the test light pulse 402. The voltage pulse 404 may be an analog signal generated by the TIA 620 and may correspond to the test light pulse 402 detected by the pulse energy measurement circuit 600. The voltage levels on the y-axis correspond to the threshold voltages V of the corresponding comparators 680-1, 680-2, ..., 680-N. T1 ,V T2 ,…,V TN The time values ​​t1, t2, t3, ..., t N-1 corresponds to the time when the voltage pulse 404 exceeds the corresponding threshold voltage, and the time values ​​t′1, t′2, t′3, . . . , t′ N-1 corresponds to the time when the voltage pulse 404 drops below the corresponding threshold voltage. For example, when the voltage pulse 404 exceeds the threshold voltage V T1 At time t1, the comparator 680-1 may generate an edge signal, and the TDC 690-1 may output a digital value corresponding to time t1. In addition, the TDC 690-1 may output a digital value corresponding to the voltage pulse 404 falling below the threshold voltage V T1 Alternatively, the pulse energy measurement circuit 600 may include an additional TDC ( Fig.13 ), the additional TDC is configured to be when the voltage pulse 404 drops below the threshold voltage V T1 The output signal 682 from the pulse energy measurement circuit 600 may include the time values ​​t1, t2, t3, ..., t N-1 and t′1, t′2, t′3, …, t′ N-1 In addition, the output signal 682 may also include one or more values ​​corresponding to the threshold voltage associated with the time value. Fig.13 The voltage pulse 404 does not exceed the threshold voltage V TN, so the corresponding comparator 680-N may not generate an edge signal. As a result, the TDC 690-N may not generate a time value, or the TDC 690-N may generate a signal indicating that no edge signal was received.

[0166] In some embodiments, the reception time of the test light pulse 402 may correspond to (i) a time associated with a peak of the voltage pulse 404, (ii) a time associated with a temporal center of the voltage pulse 404, or (iii) a time associated with a rising edge of the voltage pulse 404. Fig.13 In the peak voltage (V peak ) can be based on the threshold voltage V T(N-1) to determine (for example, time t N-1 and t′ N-1 The average value of the output signal 682 may correspond to the peak voltage time). As another example, a curve fitting or interpolation operation may be applied to the value of the output signal 682 to determine the time associated with the peak voltage or rising edge. A curve may be fitted to the value of the output signal 682 to produce a curve that approximates the shape of the test light pulse 402, and the time associated with the peak or rising edge of the curve may correspond to the peak voltage time or the rising edge time. As another example, a curve fitted to the value of the output signal 682 of the pulse energy measurement circuit 600 may be used to determine the time associated with the time center of the voltage pulse 404 (e.g., the time center may be determined by calculating the centroid or weighted average of the curve). In various embodiments, a processor and / or controller of the lidar system determines the shape of the test light pulse 402 based on one or more time values ​​generated by one or more of the TDCs 690. If the determined shape is different from the expected shape, the processor and / or controller may send an alarm that the lidar system is not operating normally in response to determining that the shape of the test light pulse 402 is different from the expected shape.

[0167] In some embodiments, the duration of the test light pulse 402 is determined. The duration can be determined from the duration or width of the corresponding voltage pulse 404. For example, the difference between two time values ​​of the output signal 682 can be used to determine the duration of the test light pulse 402. Fig.13In the example of , the duration of the test light pulse 402 corresponding to the voltage pulse 404 can be determined from the difference (t′3-t3), which can correspond to the received light pulse having a pulse duration of 4 nanoseconds. As another example, the controller can apply a curve fitting or interpolation operation to the value of the output signal 682, and the duration of the light pulse can be determined based on the width of the curve (e.g., the half-height full width of the curve). In various embodiments, the processor and / or controller of the lidar system determines the duration of the test light pulse 402 based on one or more time values ​​generated by one or more TDCs 690. If the determined duration is different from the expected duration, the processor and / or controller can send an alarm that the lidar system is not operating normally in response to determining that the duration of the test light pulse 402 is different from the expected duration.

[0168] In certain embodiments, a time correction or offset may be applied to the determined emission time to account for signal delays within the lidar system. For example, there may be a 2 ns time delay between the electrical trigger signal that initiates the emission of the light pulse and the time when the emitted light pulse leaves the lidar system. To account for the 2 ns time delay, a 2 ns offset may be added to the initial emission time determined by the pulse energy measurement circuit 600 or a controller of the lidar system. For example, the pulse energy measurement circuit 600 may be added to the time t TRIG An electrical trigger signal is received indicating that a light pulse is emitted by a corresponding light source. To compensate for the 2 ns delay between the trigger signal and the light pulse leaving the lidar system, the emission time of the light pulse can be indicated as (t TRIG +2ns).

[0169] Fig.14 An example lidar system including a beam splitter and pulse energy measurement circuit is shown. Figure 3 The laser radar system 100, Fig.14 The laser radar system 100 includes an example rotating polygonal mirror 301. For example, the scanner 120 of the laser radar system 100 includes a polygonal mirror 301, which is configured to span a horizontal FOR (FOR) for each horizontal scan line. H ) to scan the output beam 125 in a suitable field of view (FOR). Fig.14 In the example of FIG. 1 , the scanner 120 includes two scanning mirrors: (1) along θ x The polygon mirror 301 rotates in the direction of (2) along θ yThe scanning mirror 302 oscillates back and forth in a certain direction. The light source 110 generates an emitted light beam 124, which is split into an output light beam 125 and a test light beam 126 by a beam splitter 470. Since the light source 110 is configured to output light pulses, the emitted light beam 124 includes an emitted pulse 400, the output light beam 125 includes an output pulse 401, and the test light beam 126 includes a test pulse 402. Using the scanning mirror 302 and the polygon mirror 301, the output light beam 125 is directed out of the opening of the housing of the laser radar system 100 and passes through the window 350. In various embodiments, the window 350 covers the opening of the housing of the laser radar system 100 and allows the output light beam 125 to be sent toward the target environment while also providing protection to the laser radar system 100 from environmental factors. The housing opening covered by the window 350 has defined edges 351a and 351b.

[0170] In some embodiments, Fig.14 The laser radar system 100 is Figure 1-4 The laser radar system 100, the light source 110 is Figure 1 , Figure 3 , Figure 6 , Fig. 9 and / or Fig.10 The light source 110, the pulse energy circuit 600 is Figure 6 , Fig. 9 , Fig.10 and / or Fig.11 The pulse energy circuit 600 and / or Fig.12 and / or Fig.13 The pulse energy measurement circuit 600, the optical splitter 470 is Figure 6-9 , Fig.10 and / or Fig.11 The beam splitter 470, the output beam 125 is Figure 1-4 and / or Figure 6-11 The output beam 125, and the test pulse 402 is Figure 6 and / or Figure 9-13 In some embodiments, the scanner 120 and its components including the polygon mirror 301 and the scanning mirror 302 are respectively Figure 1 and / or Figure 3 The scanner 120 and / or Figure 3 The corresponding polygon mirror 301 and scanning mirror 302. In various embodiments, Fig.14 The laser radar system 100 scans as shown in FIG. Figure 3The target environment. The laser radar system 100 includes a pulse energy measurement circuit (which includes a beam splitter 470) and a pulse energy circuit 600, which is at least partially used to measure the pulse energy associated with a single light pulse such as an emitted pulse 400, an output pulse 401, and / or a test pulse 402. By using the disclosed pulse energy measurement circuit to measure the pulse energy of a single pulse, the laser radar system 100 can confirm that the light source 110 is operating at the correct power level, including being in a power-off and / or properly attenuated state at the appropriate time. For example, when the polygonal mirror 301 directs the output light beam 125 out of the opening of the housing of the laser radar system 100 (i.e., the opening at least partially defined by the edges 351a and 351b) and through the window 350, the light source 110 can be powered on and send the corresponding output pulse 401. Conversely, when the polygonal mirror 301 is not positioned to direct the output light beam 125 to pass through the housing opening and through the window 350, the light source 110 can be attenuated and / or turned off. For example, when scanning until edge 351a and beyond edge 351b (shown as Fig.14 In some embodiments, the light source 110 may be turned off or the power may be reduced. Fig.14 The portion shown by the hashed triangular area corresponds to a dark period of the lidar system 100 when no output light beam is directed out of the lidar system 100.

[0171] In some embodiments, the polygon mirror 301 is configured along θ x The output beam 125 is rotated in the substantially horizontal direction and scanned along the θ direction. x The rotation of the direction may refer to the rotational movement of the mirror 301 causing the output beam 125 to scan along a substantially horizontal direction. Fig.14 , the reflector 302 is along θ y The output beam 125 is pivoted in the substantially vertical direction and scans the output beam 125 in a substantially vertical direction. In certain embodiments, as the polygon mirror 301 rotates, the output beam 125 can be sequentially reflected from the reflective surfaces 320A, 320B, 320C, and 320D. This causes the output beam 125 to be scanned along a particular scan axis (e.g., a horizontal scan axis) to generate a sequence of scan lines, wherein each scan line corresponds to a reflection of the output beam 125 from one of the reflective surfaces of the polygon mirror 301. Fig.14, the output beam 125 is reflected from the reflective surface 320A to produce a scan line. Then, as the polygonal mirror 301 rotates, the output beam 125 reflects off the reflective surfaces 320B, 320C and 320D to produce second, third and fourth corresponding scan lines. In a particular embodiment, the laser radar system 100 is configured so that the output beam 125 is first reflected from the scanning mirror 302, and then reflected from the polygonal mirror 301. For example, the emitted light beam 124 is split by the beam splitter 470 to produce the output beam 125. The output beam 125 is first directed to the scanning mirror 302, where it is reflected by the reflective surface 321, and then the output beam 125 is directed to the polygonal mirror 301, where it is reflected by the reflective surface 320A.

[0172] Fig.15 An example graph showing the optical power of an output beam plotted against time is shown. In the example shown, Fig.15 The graph shows that as the rotation Fig.14 The polygon mirror 301 is used to scan the output beam 125 along a specific scan axis (e.g., a horizontal scan axis) to generate a sequence of two scan lines corresponding to the scan lines 230A and 230B, and the Fig.14 The optical power of the laser radar system 100. Fig.15 As shown in , the optical power changes between the value P and 0. When the light source is turned off, Fig.14 The light source 110 is powered off or attenuated to reduce the optical power to 0. These time periods correspond to Fig.14 The polygon mirror 301 is not positioned to direct the output beam 125 between the edges 351a and 351b through the window 350 toward the target environment. For example, the portion of the curve attributed to the scan line 230A corresponds to the time period when the output beam 125 is reflected out of the window 350. Fig.14 When one of the reflective surfaces 320A, 320B, 320C or 320D is used to produce a single scan line. Fig.14 The polygon mirror 301 continues to pivot, and once it reaches the edge 351b, the darkening cycle begins. Fig.14 As shown in the graph of , the light source is turned off (and / or attenuated) during the dark period. In various embodiments, by de-energizing the light source during the dark period, stray light pulses directed within the housing of the lidar system 100 are reduced, thereby allowing the lidar system 100 to operate more efficiently and accurately and / or perform additional functions, such as additional testing and / or monitoring functions. Fig.14 The polygon mirror 301 continues to pivot, and when it reaches the edge 351a, the darkening period ends, and as the output light beam 125 is reflected out Fig.14 The next reflecting surface of the polygon mirror 301 and is guided through Fig.14In some embodiments, the window 350 of the light source is closed to generate the second scan line 230B. Fig.15 The hashed areas in the graph correspond to Fig.14 The hashed triangle area corresponds to the pivot Fig.14 In various embodiments, for the portion associated with scan lines 230A and 230B, Fig.15 The power values ​​shown in the graph are average power values ​​and the power value of each scanning line corresponds to a plurality of output pulses.

[0173] Fig.16 is a flow chart illustrating an embodiment of a process for a lidar system for detecting an object. Fig.16 During the process of detecting objects, the LiDAR system can detect objects such as objects in the direction of the LiDAR system. For example, a vehicle equipped with the disclosed LiDAR system can detect other vehicles, pedestrians, lane markings, street signs, etc. in the direction of the vehicle. Depending on the orientation and number of LiDAR systems installed on the vehicle, different energy fields can be scanned to determine the corresponding environment around the vehicle. The captured environmental data can be used to implement vehicle safety features as well as autonomous driving features. In various embodiments, Fig.16 The process may be performed by the disclosed laser radar system to detect an object along the transmission direction by emitting light pulses of one or more wavelengths. When the emitted light pulses hit the object, at least a portion of the scattered light and / or reflected light may be captured by the laser radar system as part of the input light beam. In some embodiments, performing Fig.16 The process of the LiDAR system is Figure 1-4 and / or Fig.14 The laser radar system 100, and the light source of the laser radar system is Figure 1 , Figure 3 , Figure 6 , Fig. 9 , Fig.10 and / or Fig.14 A light source 110 is provided.

[0174] At 1601, one or more light beams are emitted. For example, the output light beam is emitted from the laser radar system as a light pulse. In some embodiments, the laser radar system emits multiple output light beams, each output light beam potentially offset and / or scanning a different energy field of view. In some embodiments, one or more different output light beams are at different wavelengths, and the output light beams of different wavelengths can be separated in time by coded time delays. The coded time delay used can be stored as a history of the coded time delays sent, for example, and used to match the received reflected light with the original transmission source. In various embodiments, each output light beam and the corresponding output pulse can reach an object in the emission direction and can be scattered and / or reflected by the object in the emission direction. In some embodiments, each light source for emitting a light beam can include a configurable laser capable of emitting light pulses of different wavelengths. In some embodiments, the single pulse energy of one or more output light pulses is monitored and used to operate the laser radar system. For example, based on the measured pulse energy of the light pulse, it can be confirmed that the power of the light source of the laser radar system is powered on, powered off, and / or properly attenuated. As another example, a fault condition can be identified and triggered by comparing the pulse energy of the measured light pulse with its expected pulse energy.

[0175] At 1603, scattered light is received. For example, light scattered and / or reflected by an object is received at the lidar sensor. The corresponding object may be an object along the emission direction. In various embodiments, the received light has a specific wavelength and corresponds to one of the light beam and the corresponding light pulse emitted at 1601. For example, the lidar system emits light pulses of different wavelengths and receives scattered light associated with the different emitted pulses.

[0176] At 1605, the received scattered light is analyzed. For example, the received scattered light is directed to a receiver assembly of the lidar system, where sensor data can be captured and analyzed. In some embodiments, the receiver assembly includes a receiving lens for focusing the received scattered light onto a readout integrated circuit (ROIC) of the receiver, and one or more detector site locations of the detector plane are positioned on the readout integrated circuit. The detector site locations can be used to detect a scattering pattern associated with the received scattered light, and different detector site locations can be at least partially offset to minimize crosstalk between light corresponding to different target output beams. In some embodiments, the received scattered light includes multiple wavelengths, which are then separated into different corresponding received pulses by wavelength.

[0177] Using a detector located at the detector site location, sensor data can be captured and sensor readings analyzed. In some embodiments, the analysis is performed at least in part by a readout integrated circuit (ROIC) and / or a processor of the receiver and / or a controller of the lidar system. The processing may include determining an output signal corresponding to the detected scattering pattern. In some embodiments, the output signal is a sensor reading corresponding to a measurement of the detected scattered light, such as an intensity reading or another measured sensor reading. In some embodiments, the received scattered light is associated into groups of received light pulses, and the timing between different light pulses in the group is measured. Based on the measured timing, different light pulses are distinguished from each other and used to identify corresponding transmitted pulses to match the received pulses.

[0178] At 1607, sensor readings are provided. For example, one or more sensor readings are provided in response to the analysis of the received scattered light performed at 1605. The sensor readings can be intensity readings and / or another one or more measurements. In some embodiments, the sensor readings include position and / or distance data. For example, the sensor readings can correspond to a point cloud of objects detected in the field of view based on a scan of the lidar system.

[0179] Fig.17 is a flow chart illustrating an embodiment of a process for monitoring light pulses of an emitted light beam. Fig.17 During the process of transmitting the light pulses generated by the light source of the LiDAR system, the LiDAR system can monitor the light pulses generated by the light source of the LiDAR system. In various embodiments, various characteristics of the monitored light pulses are measured, such as peak voltage, power, energy, and / or reception time. The LiDAR system can process the monitored measurements to improve performance, efficiency, and / or manage the operation of the LiDAR system. For example, the monitored measurements can be used to confirm that the light source is properly powered off during dark periods and / or that the power level of the emitted light pulses is within the expected operating range. In some embodiments, the monitored measurements are used to detect whether the LiDAR system is operating correctly. In some embodiments, as the light pulses of the light beam are emitted, Fig.17 The process of Fig.16 The laser radar system at 1601 is executed. In some embodiments, the laser radar system is Figure 1-4 and / or Fig.14 In various embodiments, the laser radar system 100 Fig.17 During the process, the light source and other related components of the lidar system are controlled by a processor and / or controller (such as Figure 1 Controlled by controller 150).

[0180] At 1701, a light beam including light pulses is generated. For example, a light source of a lidar system generates a light beam including light pulses of a specific wavelength. In some embodiments, the light beam is generated by a seed laser and can be amplified by a semiconductor optical amplifier (SOA) and / or a fiber amplifier. In some embodiments, the light beam is generated by a laser. Figure 1 , Figure 3 , Figure 6 , Fig. 9 , Fig.10 and / or Fig.14 The light source 110 generates Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 and / or Fig.14 The emitted light beam 124, and the light pulses included are Figure 6 , Fig. 9 , Fig.10 , Fig.11 and / or Fig.14 The emitted pulse is 400.

[0181] At 1703, the light beam is split into a test light pulse and an output light pulse. For example, the transmitted light beam generated at 1701 includes a transmitted light pulse that is split into a test light pulse and an output light pulse by a beam splitter. The output light pulse can be directed toward a scanner and aimed at a target environment around the laser radar system. The test light pulse can be directed toward a pulse energy circuit to perform a measurement on the test pulse. In some embodiments, the beam splitter is Figure 6-11 and / or Fig.14 The beam splitter 470, the pulse energy circuit is Figure 6 , Figure 9-11 and / or Fig.14 The pulse energy circuit 600 and / or Fig.12 and / or Fig.13 The pulse energy measurement circuit 600, and the test light pulse is Figure 6 and / or Figure 9-14 402. In various embodiments, the transmitted light pulse is split into a test light pulse and an output light pulse based on a configured split ratio. Using the configured split ratio, for certain measurements such as pulse energy, the measurement determined for the test pulse can be used to determine a corresponding measurement for the transmitted pulse and / or the output pulse.

[0182] At 1705, a measurement of a test light pulse including a single amount of energy is determined. For example, one or more measurements of the test pulse may be determined, such as a single voltage peak measurement of the test pulse. In some embodiments, the pulse measurements are determined at least in part using a pulse energy circuit. In some embodiments, the timing of the test pulse is determined and output with other measurements of the test pulse. For example, a numerical value determined based on the peak voltage of the voltage pulse of the test pulse may be output with the test pulse timing to determine and track the pulse energy of the test pulse. In some embodiments, additional timing measurements may be determined, including a start time of the pulse and an end time of the pulse. In some embodiments, the measurements determined for the test pulse include a duration and / or shape of the test pulse. In some embodiments, the reception time determined for the test pulse corresponds to the output of a corresponding output pulse split from the transmitted pulse at 1703.

[0183] At 1707, the test light pulse measurements are processed. For example, the measurements determined for the test light pulses at 1705 are processed to manage the operation of the laser radar system. In some embodiments, the test light pulse measurements are processed using a processor and / or controller of the laser radar system. For example, the amount of a single pulse energy of the light pulse can be determined by the processor and / or controller based on the test light pulse measurements (such as the digital peak voltage determined at 1705). In some embodiments, the result of the processing is used to determine whether the laser radar system is operating correctly. If the system is not operating correctly, an alarm that the system is not operating correctly can be sent and / or the system can be placed in a failover or auxiliary operating mode. As another example, in some embodiments, the processed pulse measurements are used to determine whether the laser radar system is operating within the expected operating conditions and / or whether the instructions to power on, power off, and / or attenuate the light source are successful. For example, when it is determined that one or more test pulses are below a specific operating energy, an instruction can be sent to increase the energy of the emitted light pulses. By comparing the processed test pulse measurements with the expected values, it can be determined whether the instructions are successfully sent and executed and whether the emitted pulses are adjusted to be consistent with the instructions. As another example, the energy of one or more test light pulses may be determined to be below a certain minimum energy or outside an operating energy range. In response to any determination, an alert may be sent that the lidar system is not operating properly. In some embodiments, the alert includes an instruction to shut down the lidar system or at least a portion of the lidar system.

[0184] In some embodiments, the determined pulse energy of the output pulse is used at least in part to determine the reflectivity of the target. For example, a receiver of a lidar system determines the energy of a received light pulse that includes a portion of the output light pulse that is scattered by a target located at a certain distance from the lidar system. The lidar system can determine the reflectivity of the target based on the energy of the received light pulse, the energy of the output light pulse, and the distance from the lidar system to the target.

[0185] At 1709, an output light pulse is emitted from the lidar system. For example, as part of a scanning process, the output pulse is emitted toward a target environment to detect an object in the surrounding environment. In various embodiments, the output light pulse is emitted while the test pulse is measured at 1705 and / or while the test pulse measurement is processed at 1707. In various embodiments, although the measurement determined at 1705 and processed at 1707 is based on the test pulse, due to the relationship between the emitted pulse, the test pulse, and the output pulse, the result is related to all three pulses including the output pulse emitted at 1709.

[0186] Fig.18 is a flow chart illustrating an embodiment of a process for determining a measurement of a light pulse. Fig.18 In some embodiments, the process is performed at least in part by a pulse energy circuit of the laser radar system. In some embodiments, the pulse energy circuit is Figure 6 , Figure 9-11 and / or Fig.14 The pulse energy circuit 600 and / or Fig.12 and / or Fig.13 The pulse energy measurement circuit 600. In some embodiments, the measured optical pulse is Figure 6 and / or Figure 9-14 In some embodiments, Fig.18 The process in Fig.17 Executed at 1705 and / or 1707.

[0187] At 1801, a light pulse is received. For example, a light pulse such as a test pulse split from an originally emitted pulse is received. In some embodiments, the light pulse can be received and detected by a detector such as a photodetector. In some embodiments, a light pulse is received and a corresponding photocurrent pulse is generated and converted to a voltage pulse. The voltage pulse can be used as an input voltage signal of step 1803.

[0188] At 1803, the voltage peak of the light pulse is detected and held. For example, the peak voltage associated with the light pulse received at 1801 is determined and output as a voltage signal such as a peak held voltage signal. In some embodiments, the peak value is detected by a peak hold circuit such as Fig.12 The peak hold circuit 630 and / or Fig.13 In some embodiments, the voltage peak is determined based on a voltage signal corresponding to a voltage pulse of the received test pulse.

[0189] At 1805, the peak held voltage signal is buffered. In some embodiments, the peak held voltage signal generated at 1803 is passed through a buffer amplifier. For example, the peak held voltage can be passed through a buffer amplifier to prepare a voltage signal for signal processing. In some embodiments, the voltage signal corresponding to the peak held voltage of the test pulse is buffered to prevent the signal analysis and subsequent processing performed from interfering with other functions of the pulse energy circuit.

[0190] At 1807, signal analysis is performed and the determined pulse measurement is output. For example, signal analysis is performed on the buffered peak held voltage signal to determine the corresponding peak voltage of the test pulse as a numerical value. In some embodiments, the signal analysis is performed by an analog-to-digital converter (ADC), one or more comparators, and / or one or more time-to-digital converters (TDCs). For example, the ADC can be used at least in part to determine and encode a numerical value corresponding to the peak voltage of the test pulse based on the buffered peak held voltage signal. In some embodiments, the analysis is performed based on a trigger signal, such as a trigger signal initiated by a rising edge of the test pulse and / or its corresponding voltage signal. In various embodiments, additional measurements can be determined, including timing measurements, such as the reception time of the test pulse, the shape of the test pulse, the duration of the test pulse, the time of the rising edge of the test pulse, and / or the time of the falling edge of the test pulse, etc. In various embodiments, a processor and / or controller of the laser radar system can determine the amount of single pulse energy of the light pulse based on the determined numerical pulse measurement. The pulse energy of the output pulse can also be determined by the relationship between the output pulse and the measured corresponding test pulse.

[0191] At 1809, the peak hold voltage is reset. For example, once the test pulse is analyzed at 1807 and the associated measurement is determined for the test pulse, the peak voltage detected for the test pulse and held at 1803 can be reset. In various embodiments, the peak hold voltage is reset in anticipation of measuring the peak voltage of the next test pulse. In some embodiments, the peak hold voltage is reset by sending a reset signal to the peak hold circuit. In some embodiments, the reset signal is triggered based on a reset timer. For example, the reset timer is configured to send a reset signal when a configured timer expires. In some embodiments, the timer is configured to analyze the amount of time required for the test pulse and can be based on when the peak hold voltage signal of the test pulse is no longer needed.

[0192] Fig.19 is a flow chart illustrating an embodiment of a process for initiating signal analysis of a light pulse. Fig.19 In various embodiments, the process of initiating a signal analysis of the monitored optical pulse based on the detection of the optical pulse exceeding a configured threshold voltage. Fig.19 The process is used to initiate the evaluation of the test pulse to determine the single pulse energy of the detected light pulse based on its peak voltage. In some embodiments, Fig.19 The process is performed at least in part by a threshold detector of a pulse energy measurement circuit (such as Fig.12 The threshold detector 660 of the pulse energy measurement circuit 600) Fig.18 1807 is executed. In some embodiments, Fig.19 The process further utilizes and relies on additional components of the pulse energy measurement circuit, such as peak hold circuit, buffer amplifier, analog-to-digital converter (ADC), reset timer, and timer. For example, Fig.19 The process can be used Fig.12 The peak holding circuit 630, the buffer amplifier 640, the analog-to-digital converter (ADC) 650, the threshold detector 660, the reset timer 670 and the timer 671 are provided.

[0193] At 1901, a peak hold voltage signal corresponding to a detected light pulse is received. For example, a light pulse is detected, and at 1901, a voltage signal corresponding to a peak value of a voltage pulse of the light pulse is received at a threshold detector. The threshold detector is configured with a voltage threshold (V T ), which is used to trigger signal analysis of the light pulse at the appropriate time. In some embodiments, the peak hold voltage signal is a buffered peak hold voltage signal through a buffer amplifier. In some embodiments, the peak hold voltage signal is at least partially generated by a peak hold circuit.

[0194] At 1903, it is determined whether the peak voltage value exceeds a voltage threshold (V TIf the peak voltage exceeds the voltage threshold (V T ), the process proceeds to 1905. For example, when the voltage value of the peak hold voltage signal received at 1901 exceeds the configured voltage threshold (V T ), the process proceeds to 1905. In various embodiments, the start of the light pulse and its rising edge correspond to exceeding a voltage threshold (V T ) peak voltage value. If the peak voltage value does not exceed the voltage threshold (V T ), the process returns to 1901.

[0195] At 1905, the reception time of the light pulse is determined. For example, at 1903, based on detecting that the peak voltage value exceeds the voltage threshold (V T ) to determine the reception time of the light pulse. In some embodiments, the reception time is determined by sending a trigger signal to a timer. In some embodiments, the trigger signal is Fig.12 The trigger signal 662, and the timer is Fig.12 A timer 671 is provided. When the timer receives a trigger signal, the timer marks the current time and associates it with the current light pulse. In some embodiments, the current time is offset by a certain offset to more accurately identify the required reception time of the light pulse. For example, the reception time may correspond to a peak, a rising edge, a time center, and / or a falling edge. In some embodiments, multiple reception times are determined and provided as part of the output signal. In some embodiments, the reception time of the light pulse can be used to determine whether the light pulse is outside the reception time interval. A light pulse with a reception time outside the reception time interval may cause an alarm to be sent that the lidar system is not operating normally.

[0196] At 1907, signal analysis of the light pulse is initiated. For example, a trigger signal is sent to an analog-to-digital converter (ADC), a controller, and / or a processor to initiate analysis of the light pulse. In some embodiments, the trigger signal is Fig.12 The trigger signal 662 is sent to start Fig.12The analog-to-digital converter (ADC) 650 processes the input parameters based on the detected light pulses. For example, when the ADC receives a trigger signal to start processing, the ADC analyzes the analog input it receives and converts it into one or more digital output signals. In various embodiments, the input of the ADC is a peak-hold voltage signal corresponding to the peak voltage of the detected light pulse. In some embodiments, the signal analysis triggered by the ADC can include determining a numerical value corresponding to the energy of the light pulse based on the peak-hold voltage signal of the provided light pulse. In some embodiments, the peak-hold voltage signal is a buffered peak-hold voltage signal through a buffer amplifier. In some embodiments, the output of the ADC of the numerical value corresponding to the energy of the light pulse starts the processor and / or controller of the laser radar system to determine the amount of single pulse energy of the light pulse based at least in part on the provided numerical value.

[0197] At 1909, a reset timer is started. For example, a trigger signal is sent to the reset timer to initiate the start of the reset timer. In various embodiments, the reset timer is configured with a timer that sends a reset signal to reset the peak hold voltage signal when a time period of the timer expires. In some embodiments, the reset timer is Fig.12 The reset timer 670, and the reset timer via Fig.12 The trigger signal 662 is started.

[0198] Fig. 20 is a flow chart illustrating an embodiment of a process for outputting a peak hold voltage signal for measuring a light pulse. Fig. 20 In various embodiments, the peak voltage value of the voltage signal corresponding to the light pulse is output as the peak hold voltage signal. Fig. 20 The process is performed by Fig.12 In some embodiments, the peak holding circuit 630 is used to perform the peak holding circuit. Fig. 20 The peak hold voltage signal generated by the process output is used to detect the light pulse and determine the pulse energy of the detected light pulse. In various embodiments, the peak hold voltage is initialized to an initial value, such as a reset value.

[0199] At 2001, an input voltage signal is received. For example, a voltage signal corresponding to a voltage pulse of a light pulse is received. In some embodiments, by using a transimpedance amplifier (TIA) such as Fig.12 A transimpedance amplifier (TIA) 620) generates a voltage signal of a voltage pulse from a photocurrent pulse of a light pulse.

[0200] At 2003, it is determined whether a new peak voltage is detected. If a new peak voltage is detected, the process proceeds to 2005 to update the peak hold voltage. If a new peak voltage is not detected, the process proceeds to 2007 and the existing peak voltage is held without change.

[0201] At 2005, the peak held voltage is updated. For example, the peak voltage held and associated with the light pulse is updated using the newly detected peak voltage. In various embodiments, the peak voltage is determined at least in part by a signal such as Fig.12 The capacitor C1 of the peak holding circuit 630 is used to hold the capacitor.

[0202] At 2007, it is determined whether a reset is received. If a reset is received, the process proceeds to 2009. If a reset is not received, for example, the reset signal is not activated, the process proceeds to 2011.

[0203] At 2009, the peak hold voltage is reset. Triggered by the reset detected at 2007, the peak hold voltage is reset. In various embodiments, the peak hold voltage is reset to a reset value to prepare the peak hold circuit to detect the peak voltage of the next light pulse. In some embodiments, the peak hold circuit is reset by releasing the energy held by the capacitor of the peak hold circuit.

[0204] At 2011, a peak hold voltage value is provided. For example, a peak hold circuit outputs a peak hold voltage signal. The peak hold voltage signal provides the current peak hold voltage of the light pulse. In some embodiments, the peak hold voltage signal is provided to a threshold detector to detect the rising edge of the light pulse and determine its single pulse energy.

[0205] Fig.21 An example computer system 2100 is shown. In particular embodiments, one or more computer systems 2100 may perform one or more steps of one or more methods described or illustrated herein. In particular embodiments, one or more computer systems 2100 may provide functionality described or illustrated herein. In particular embodiments, software running on one or more computer systems 2100 may perform one or more steps of one or more methods described or illustrated herein, or may provide functionality described or illustrated herein. Particular embodiments may include one or more portions of one or more computer systems 2100. In particular embodiments, a computer system may be referred to as a processor, a controller, a computing device, a computing system, a computer, a general purpose computer, or a data processing apparatus. Herein, reference to a computer system may encompass one or more computer systems, where appropriate. In some embodiments, the computer system 2100 is used to perform Figure 16-20 one or more of the processes.

[0206] Computer system 2100 can take any suitable physical form. For example, computer system 2100 can be an embedded computer system, a system on a chip (SOC), a single board computer system (SBC), a desktop computer system, a laptop or notebook computer system, a mainframe, a grid of computer systems, a server, a tablet computer system, or any suitable combination of two or more thereof. As another example, all or part of computer system 2100 can be combined, coupled or integrated into various devices, including but not limited to: cameras, video cameras, personal digital assistants (PDAs), mobile phones, smart phones, electronic reading devices (such as e-readers), game consoles, smart watches, clocks, calculators, television monitors, flat panel displays, computer monitors, vehicle displays (such as odometer displays or dashboard displays), vehicle navigation systems, laser radar systems, ADAS, autonomous vehicles, autonomous vehicle driving systems, cockpit controllers, camera view displays (such as displays of rear-view cameras in vehicles), glasses or head-mounted displays. Where appropriate, the computer system 2100 may include one or more computer systems 2100; be single or distributed; span multiple locations; span multiple machines; span multiple data centers; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems 2100 may perform one or more steps of one or more methods described or shown herein without substantial spatial or temporal limitations. As an example, one or more computer systems 2100 may perform one or more steps of one or more methods described or shown herein in real time or in batch mode. Where appropriate, one or more computer systems 2100 may perform one or more steps of one or more methods described or shown herein at different times or in different locations.

[0207] like Fig.21 As shown in the example of , computer system 2100 may include processor 2110, memory 2120, storage device 2130, input / output (I / O) interface 2140, communication interface 2150, or bus 2160. Computer system 2100 may include any suitable components in any suitable number in any suitable arrangement.

[0208] In certain embodiments, the processor 2110 may include hardware for executing instructions, such as those constituting a computer program. As an example, to execute instructions, the processor 2110 may fetch (or obtain) instructions from an internal register, an internal cache, a memory 2120, or a storage device 2130; decode and execute them; and then write one or more results to an internal register, an internal cache, a memory 2120, or a storage device 2130. In certain embodiments, the processor 2110 may include one or more internal caches for data, instructions, or addresses. Where appropriate, the processor 2110 may include any suitable number of any suitable internal caches. As an example, the processor 2110 may include one or more instruction caches, one or more data caches, or one or more translation lookaside buffers (TLBs). The instructions in the instruction cache may be copies of instructions in the memory 2120 or the storage device 2130, and the instruction cache may speed up the processor 2110 to obtain those instructions. The data in the data cache may be a copy of the data in the memory 2120 or the storage device 2130 for instructions executed at the processor 2110 to operate; the result of a previous instruction executed at the processor 2110 for accessing or writing to the memory 2120 or the storage device 2130 by subsequent instructions executed at the processor 2110; or other suitable data. The data cache may speed up the read or write operation of the processor 2110. The TLB may speed up the virtual address translation of the processor 2110. In a particular embodiment, the processor 2110 may include one or more internal registers for data, instructions, or addresses. Where appropriate, the processor 2110 may include any suitable number of any suitable internal registers. Where appropriate, the processor 2110 may include one or more arithmetic logic units (ALUs); may be a multi-core processor; or may include one or more processors 2110.

[0209] In certain embodiments, the memory 2120 may include a main memory for storing instructions for execution by the processor 2110 or data for operation by the processor 2110. As an example, the computer system 2100 may load instructions from the storage device 2130 or another source (such as, for example, another computer system 2100) to the memory 2120. The processor 2110 may then load the instructions from the memory 2120 to an internal register or an internal cache. To execute the instructions, the processor 2110 may fetch the instructions from the internal register or the internal cache and decode them. During or after the execution of the instructions, the processor 2110 may write one or more results (which may be intermediate or final results) to the internal register or the internal cache. The processor 2110 may then write one or more of these results to the memory 2120. One or more memory buses (which may each include an address bus and a data bus) may couple the processor 2110 to the memory 2120. The bus 2160 may include one or more memory buses. In certain embodiments, one or more memory management units (MMUs) may reside between the processor 2110 and the memory 2120 and facilitate access to the memory 2120 requested by the processor 2110. In certain embodiments, the memory 2120 may include a random access memory (RAM). Where appropriate, the RAM may be a volatile memory. Where appropriate, the RAM may be a dynamic RAM (DRAM) or a static RAM (SRAM). Where appropriate, the memory 2120 may include one or more memories 2120.

[0210] In a particular embodiment, the storage device 2130 may include a mass storage device for data or instructions. As an example, the storage device 2130 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. Where appropriate, the storage device 2130 may include a removable or non-removable (or fixed) medium. Where appropriate, the storage device 2130 may be inside or outside the computer system 2100. In a particular embodiment, the storage device 2130 may be a non-volatile solid-state memory. In a particular embodiment, the storage device 2130 may include a read-only memory (ROM). Where appropriate, the ROM may be a mask ROM (MROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a flash memory, or a combination of two or more of these. Where appropriate, the storage device 2130 may include one or more storage control units that facilitate communication between the processor 2110 and the storage device 2130. Where appropriate, the storage device 2130 may include one or more storage devices 2130.

[0211] In a particular embodiment, the I / O interface 2140 may include hardware, software, or both, providing one or more interfaces for communication between the computer system 2100 and one or more I / O devices. Where appropriate, the computer system 2100 may include one or more of these I / O devices. One or more of these I / O devices may enable communication between a person and the computer system 2100. As an example, the I / O device may include a keyboard, a keypad, a microphone, a monitor, a mouse, a printer, a scanner, a speaker, a camera, a stylus, a tablet computer, a touch screen, a trackball, another suitable I / O device, or any suitable combination of two or more of these. The I / O device may include one or more sensors. Where appropriate, the I / O interface 2140 may include one or more devices or software drivers that enable the processor 2110 to drive one or more of these I / O devices. Where appropriate, the I / O interface 2140 may include one or more I / O interfaces 2140.

[0212] In certain embodiments, the communication interface 2150 may include hardware, software, or both that provides one or more interfaces for communication (such as, for example, packet-based communication) between the computer system 2100 and one or more other computer systems 2100 or one or more networks. As an example, the communication interface 2150 may include a network interface controller (NIC) or a network adapter for communicating with an Ethernet or other wired-based network or a wireless NIC (WNIC); a wireless adapter for communicating with a wireless network (such as a WI-FI network); or an optical transmitter (e.g., a laser or light emitting diode) or an optical receiver (e.g., a photodetector) for communicating using fiber optic communication or free space optical communication. The computer system 2100 may communicate with one or more portions of an ad hoc network, a personal area network (PAN), an in-vehicle network (IVN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or the Internet, or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, the computer system 2100 can communicate with a wireless PAN (WPAN) (such as, for example, a BLUETOOTH WPAN), a WI-FI network, a Worldwide Interoperability for Microwave Access (WiMAX) network, a cellular telephone network (such as, for example, a Global System for Mobile Communications (GSM) network), or other suitable wireless networks, or a combination of two or more of these. As another example, the computer system 2100 can communicate using fiber optic communications based on 100 Gigabit Ethernet (100GbE), 10 Gigabit Ethernet (10GbE), or a Synchronous Optical Network (SONET). Where appropriate, the computer system 2100 may include any suitable communication interface 2150 for any of these networks. Where appropriate, the communication interface 2150 may include one or more communication interfaces 2150.

[0213] In certain embodiments, bus 2160 may include hardware, software, or both that couple components of computer system 2100 to each other. As an example, bus 2160 may include an accelerated graphics port (AGP) or other graphics bus, a controller area network (CAN) bus, an enhanced industry standard architecture (EISA) bus, a front side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an industry standard architecture (ISA) bus, an INFINIBAND interconnect, a low pin count (LPC) bus, a memory bus, a micro channel architecture (MCA) bus, a peripheral component interconnect (PCI) bus, a PCI-Express (PCIe) bus, a serial advanced technology attachment (SATA) bus, a video electronics standard association local bus (VLB), or another suitable bus or a combination of two or more of these. Where appropriate, bus 2160 may include one or more buses 2160.

[0214] In a particular embodiment, the various modules, circuits, systems, methods or algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software or any suitable combination of hardware and software. In a particular embodiment, computer software (which may be referred to as software, computer executable code, computer code, computer program, computer instructions or instructions) may be used to perform the various functions described or shown herein, and the computer software may be configured to be executed or control its operation by the computer system 2100. As an example, the computer software may include instructions configured to be executed by the processor 2110. In a particular embodiment, due to the interchangeability of hardware and software, various schematic logic blocks, modules, circuits or algorithm steps have been generally described according to function. Whether such functions are implemented in hardware, software or a combination of hardware and software may depend on the specific application or the design constraints imposed on the entire system.

[0215] In a particular embodiment, a computing device may be used to implement various modules, circuits, systems, methods, or algorithm steps disclosed herein. As an example, all or part of the modules, circuits, systems, methods, or algorithms disclosed herein may be implemented or executed by a general purpose single-chip or multi-chip processor, a digital signal processor (DSP), an ASIC, an FPGA, any other suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor), a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0216] In a specific embodiment, one or more embodiments of the subject matter described herein can be implemented as one or more computer programs (e.g., one or more modules of computer program instructions encoded or stored on a computer-readable non-transient storage medium). As an example, the steps of the method or algorithm disclosed herein can be implemented in a processor executable software module that can reside on a computer-readable non-transient storage medium. In a specific embodiment, a computer-readable non-transient storage medium may include any suitable storage medium that can be used to store or transmit computer software and can be accessed by a computer system. Here, a computer-readable non-transient storage medium or medium may include one or more semiconductor-based or other integrated circuits (ICs) (such as, for example, field programmable gate arrays (FPGAs) or application-specific ICs (ASICs)), hard disk drives (HDDs), hybrid hard disk drives (HHDs), optical disks (e.g., compact discs (CDs), CD-ROMs, digital versatile discs (DVDs), Blu-ray discs or laser discs), optical disk drives (ODDs), magneto-optical disks, magneto-optical drives, floppy disks, floppy disk drives (FDDs), magnetic tapes, flash memory, solid-state drives (SSDs), RAMs, RAM drives, ROMs, secure digital cards or drives, any other suitable computer-readable non-transient storage media, or any suitable combination of two or more of these (where appropriate). Computer-readable non-transitory storage media may be volatile, nonvolatile, or a combination of volatile and nonvolatile, where appropriate.

[0217] In particular embodiments, certain features described herein in the context of separate embodiments may also be combined and implemented in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments, either individually or in any suitable subcombination. Furthermore, while features may be described above as functioning in certain combinations and even initially claimed per se, in some cases one or more features in a claimed combination may be deleted from the combination, and a claimed combination may be directed to a subcombination or variations of a subcombination.

[0218] Although the operation can be described as occurring in a specific order in the accompanying drawings, this should not be understood as requiring such operations to be performed in the specific order or sequence shown, or requiring all operations to be performed. In addition, the accompanying drawings can schematically depict one or more example processes or methods in the form of a flow chart or sequence diagram. However, other operations not depicted can be incorporated into the schematically illustrated example processes or methods. For example, one or more additional operations can be performed before, after, at the same time or between any illustrated operations. In addition, in appropriate cases, one or more operations depicted in the figure can be repeated. In addition, the operations depicted in the figure can be performed in any suitable order. In addition, although specific components, devices or systems are described herein as performing specific operations, any suitable combination of any suitable components, devices or systems can be used to perform any suitable operation or combination of operations. In some cases, multitasking or parallel processing operations can be performed. In addition, the separation of each system component in the embodiments described herein should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can be integrated together in a single software product or packaged into multiple software products.

[0219] Various embodiments have been described in conjunction with the accompanying drawings. However, it should be understood that these drawings are not necessarily drawn to scale. As an example, the distances or angles depicted in the drawings are illustrative and may not necessarily have an exact relationship to the actual size or layout of the device shown.

[0220] The scope of the present disclosure includes all changes, substitutions, variations, alterations, and modifications to the example embodiments described or shown herein that would be understood by a person of ordinary skill in the art. The scope of the present disclosure is not limited to the example embodiments described or shown herein. In addition, although the present disclosure describes or shows the various embodiments herein as including specific components, elements, functions, operations, or steps, any of these embodiments may include any combination or arrangement of any components, elements, functions, operations, or steps described or shown anywhere herein that would be understood by a person of ordinary skill in the art.

[0221] As used herein, the term "or" should be interpreted as including or meaning any one or any combination, unless explicitly stated otherwise or the context indicates otherwise. Therefore, in this document, the expression "A or B" means "A, B, or both A and B". As another example, in this document, "A, B, or C" means at least one of the following: A; B; C; A and B; A and C; B and C; A, B, and C. An exception to this definition occurs if a combination of elements, devices, steps, or operations are inherently mutually exclusive in some respects.

[0222] As used herein, approximations such as, but not limited to, "about," "substantially," or "approximately" refer to a condition that, when so modified, is understood not to be necessarily absolute or perfect, but will be considered close enough to one of ordinary skill in the art to warrant designating the condition as existing. The extent to which the description can vary will depend on how much change can be made, and one of ordinary skill in the art still recognizes that the modified feature has the properties or capabilities required of the unmodified feature. In general, but subject to the foregoing discussion, numerical values ​​modified herein by approximations such as "about" may differ from the stated value by ±0.5%, ±1%, ±2%, ±3%, ±4%, ±5%, ±10%, ±12%, or ±15%. The term "substantially constant" refers to a value that varies by less than a specified amount over any suitable time interval. For example, a substantially constant value may vary by less than or equal to 20%, 10%, 1%, 0.5%, or 0.1% over a time interval of approximately 104s, 103s, 102s, 10s, 1s, 100ms, 10ms, 1ms, 100μs, 10μs, or 1μs. The term "substantially constant" may apply to any suitable value, such as, for example, optical power, pulse repetition frequency, current, wavelength, optical or electrical frequency, or optical or electrical phase.

[0223] As used herein, the terms "first," "second," "third," and the like may be used as labels for the nouns that precede them, and these terms may not necessarily imply a particular ordering (e.g., a particular spatial, temporal, or logical sequence). As an example, a system may be described as determining a "first result" and a "second result," and the terms "first" and "second" may not necessarily imply that the first result is determined before the second result.

[0224] As used herein, the terms "based on" and "based at least in part on" may be used to describe or present one or more factors that influence a determination, and these terms may not exclude additional factors that may influence a determination. A determination may be based only on those factors presented or may be based at least in part on those factors. The phrase "determining A based on B" means that B is a factor that influences the determination of A. In some cases, other factors may also contribute to the determination of A. In other cases, A may be determined based only on B.

[0225] Although the foregoing embodiments have been described in considerable detail for the purpose of clarity of understanding, the present invention is not limited to the details provided. There are many alternative ways to implement the present invention. The disclosed embodiments are illustrative rather than restrictive.

Claims

1. A laser radar system with pulse energy measurement, characterized in that: include: a light source configured to generate an emitted light beam comprising emitted light pulses; a beam splitter configured to split the emitted light beam to generate at least (i) a test light beam including a test light pulse including a first portion of the emitted light pulse, and (ii) an output light beam including an output light pulse including a second portion of the emitted light pulse that is allowed to at least partially exit the system; as well as A pulse energy measurement circuit is configured to receive the test light pulse and determine a numerical value corresponding to an amount of individual energy of the test light pulse.

2. The laser radar system with pulse energy measurement according to claim 1, characterized in that The pulse energy measurement circuit comprises: a detector configured to generate a photocurrent pulse corresponding to the test light pulse; an electronic amplifier configured to generate a voltage pulse corresponding to the photocurrent pulse; a peak hold circuit configured to generate a voltage signal corresponding to a peak value of the voltage pulse; and An analog-to-digital converter is configured to determine the numerical value corresponding to the amount of energy of the single test light pulse, wherein the numerical value is determined based on the voltage signal corresponding to the peak value of the voltage pulse.

3. The laser radar system with pulse energy measurement according to claim 2, characterized in that The pulse energy measurement circuit further includes a threshold detector configured to generate a trigger signal when the voltage signal rises above a specific threshold voltage, wherein the trigger signal is provided to the analog-to-digital converter to initiate determination by the analog-to-digital converter of the numerical value corresponding to the amount of the single energy of the test light pulse.

4. The laser radar system with pulse energy measurement according to claim 3, characterized in that The pulse energy measurement circuit further includes a reset timer configured to provide a reset signal to the peak hold circuit at a specific time interval after the trigger signal is generated.

5. The laser radar system with pulse energy measurement according to claim 2, characterized in that The pulse energy measurement circuit further includes a buffer amplifier located between the peak hold circuit and the analog-to-digital converter, wherein the buffer amplifier is configured to receive the voltage signal corresponding to the peak value of the voltage pulse and generate an output signal corresponding to the received voltage signal, wherein the output signal is provided to the analog-to-digital converter.

6. The laser radar system with pulse energy measurement according to claim 2, characterized in that The pulse energy measurement circuit further includes a timer configured to determine a reception time of the test light pulse.

7. The laser radar system with pulse energy measurement according to claim 1, characterized in that The pulse energy measurement circuit comprises: a detector configured to generate a photocurrent pulse corresponding to the test light pulse; an electronic amplifier configured to generate a voltage pulse corresponding to the photocurrent pulse; and A plurality of comparators and a plurality of time-to-digital converters, wherein: Each comparator of the plurality of comparators is coupled to a corresponding one of the time-to-digital converters and is configured to provide an electrical edge signal to the corresponding time-to-digital converter when the voltage pulse rises above a specific threshold voltage or falls below a specific threshold voltage; and The corresponding time-to-digital converter is configured to generate a time value corresponding to a time when the electrical edge signal is received.

8. The laser radar system with pulse energy measurement according to claim 7, characterized in that The numerical value corresponding to the amount of energy of the single test light pulse is determined based on one or more time values ​​generated by one or more of the time-to-digital converters.

9. The laser radar system with pulse energy measurement according to claim 1, characterized in that The beam splitter is configured to split the emitted light beam so that: The amount of the single energy of the test light pulse is less than or equal to 2% of the energy of the emitted light pulse; and The energy of the output light pulse is greater than or equal to 98% of the energy of the emitted light pulse.

10. The laser radar system with pulse energy measurement according to claim 1, characterized in that The emitted light pulse is one of a plurality of emitted light pulses generated by the light source, wherein the emitted light pulse has optical characteristics including the following: Wavelengths between 900 nm and 1700 nm; Pulse energies between 0.1 μJ and 100 μJ; a pulse repetition frequency between 80 kHz and 10 MHz; and Pulse duration between 1 ns and 100 ns.

11. The laser radar system with pulse energy measurement according to claim 1, characterized in that The light source includes a direct emitter laser diode configured to produce the emitted light beam.

12. The laser radar system with pulse energy measurement according to claim 1, characterized in that The light source comprises: a seed laser diode configured to generate seed light; and A semiconductor optical amplifier is configured to amplify the seed light to generate the emitted light beam.

13. The laser radar system with pulse energy measurement according to claim 1, characterized in that The light source comprises: a seed laser diode configured to generate seed light; and A fiber amplifier is configured to amplify the seed light to generate the emitted light beam.

14. The laser radar system with pulse energy measurement according to claim 1, characterized in that The light source comprises: a seed laser diode configured to generate a seed light; a semiconductor optical amplifier configured to amplify the seed light to generate an amplified seed light; and A fiber amplifier is configured to further amplify the amplified seed light to generate the emitted light beam.

15. The laser radar system with pulse energy measurement according to claim 1, characterized in that The system further comprises: a scanner configured to scan the output beam across a field of view of the system; a receiver configured to detect a received light pulse comprising a portion of the output light pulse scattered by an object located a distance from the system; and A processor is configured to determine the distance from the system to the target based on a round trip time for the portion of the output light pulse to travel to the target and back to the system.

16. The laser radar system with pulse energy measurement according to claim 15, characterized in that The scanner comprises: a first scanning mirror comprising a polygonal mirror configured to scan the output light beam along a first scanning axis to generate a plurality of scan lines; and A second scanning mirror is configured to distribute the scan line along a second scanning axis different from the first scanning axis.

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