WO2022206032A1 - 存储方法、数据处理方法、激光雷达和计算机可读存储介质 - Google Patents

存储方法、数据处理方法、激光雷达和计算机可读存储介质 Download PDF

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WO2022206032A1
WO2022206032A1 PCT/CN2021/138329 CN2021138329W WO2022206032A1 WO 2022206032 A1 WO2022206032 A1 WO 2022206032A1 CN 2021138329 W CN2021138329 W CN 2021138329W WO 2022206032 A1 WO2022206032 A1 WO 2022206032A1
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time
weight
information
detection
storage
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PCT/CN2021/138329
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English (en)
French (fr)
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杨晋
许帅骑
章洪燕
向少卿
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上海禾赛科技有限公司
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Publication of WO2022206032A1 publication Critical patent/WO2022206032A1/zh
Priority to US18/477,692 priority Critical patent/US20240019556A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G01S7/4863—Detector arrays, e.g. charge-transfer gates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G01S17/894—3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/487—Extracting wanted echo signals, e.g. pulse detection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G01S7/493—Extracting wanted echo signals

Definitions

  • the present disclosure generally relates to the technical field of photoelectric detection, and in particular, to a storage method of radar detection data, a data processing method, a laser radar, and a computer-readable storage medium.
  • Lidar is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of targets. It is an advanced detection method that combines laser technology with photoelectric detection technology. Because of its high resolution, good concealment, strong anti-active interference ability, good low-altitude detection performance, small size and light weight, lidar is widely used in autonomous driving, transportation and communication, unmanned aerial vehicles, intelligent robots, resource exploration and other fields.
  • Time-to-digital converters are often used in lidars to obtain time information, including the time of arrival of the echoes and/or the time of flight of the echoes.
  • TDC time-to-digital converter
  • the time information obtained by each measurement is accumulated into a histogram, which consumes a lot of storage space.
  • Some lidars use a similar single photon avalanche diode (SPAD) as a detector.
  • the SPAD can be triggered by a single photon avalanche, and the TDC can measure the time stamp of each trigger with picosecond precision.
  • the outputs of multiple SPADs are connected to the same TDC.
  • the TDC provides the trigger time stamp and the number cnt of SPADs that are simultaneously triggered in the macro pixel.
  • the present invention provides a storage method for radar detection data, including:
  • S101 Receive probe data, where the probe data includes time information and intensity information corresponding to the time information;
  • the first time precision is the time interval between any two adjacent first time scales, and is n times the time resolution of the detection data of the radar, where n>1;
  • the weight is associated with the time information and a time interval of at least one first time scale.
  • the weight includes a first weight and a second weight, the first weight being associated with a time interval between the time information and one of the adjacent first time scales, the first weight The second weight is associated with the time interval between the time information and another adjacent first time scale, and the step S102 includes: with the first time precision, according to the first weight and the second weight, respectively, storing the intensity information.
  • the first weight is n-x
  • the second weight is x
  • x represents the time interval between the time information and the adjacent first time scale is x times the time resolution of radar detection data Rate.
  • the first weight is the weight of the time information corresponding to the first time scale adjacent to the left thereof
  • the second weight is the first time scale adjacent to the right corresponding to the time information.
  • the weight of the time scale, where x indicates that the time interval between the time information and the first time scale adjacent to the left of the time information is x times the time resolution of radar detection data.
  • the first weight is 1-(x/n)
  • the second preset weight is x/n, where x represents the first time scale adjacent to the left of the time information
  • the time interval is x times the time resolution of the radar detection data.
  • n 2 m
  • m is a positive integer
  • the intensity information includes a triggering number of detection units.
  • the memory has a storage unit corresponding to each first time scale
  • the step S102 includes: storing the intensity information in a location corresponding to the time information according to the first weight and the second weight. in two storage units corresponding to two adjacent first time scales.
  • the step S102 further includes: when the strength information is stored in one of the storage units according to the weight,
  • the accumulated result is written into the storage unit.
  • the storage method further comprises: when it is judged that one of the storage units overflows or is about to overflow, assigning another storage address to the storage unit from the reserved register.
  • the reserved registers include N groups of registers, where N is a preset value, and each group of registers is used for a storage unit that overflows or is about to overflow.
  • the present invention also provides a data processing method that can be used for lidar, comprising:
  • S202 Determine time information based on the transmission moment of the probe pulse and the reception moment
  • the first time precision is the time interval between any two adjacent first time scales, and is n times the time resolution of the detection data of the radar, where n>1;
  • the weight is associated with the time information and a time interval of at least one first time scale.
  • the lidar scans a field of view multiple times, wherein the step S203 includes: superimposing and storing the intensity information obtained by the multiple scans with a first time precision.
  • the data processing method further includes:
  • the data processing method further includes:
  • the frontier time is:
  • the numerical value corresponding to the leading edge of the echo pulse is compared with a preset threshold value, and the time information corresponding to the numerical value whose intensity is equal to the preset threshold value is used as the leading edge time.
  • the present invention also provides a laser radar, comprising:
  • a transmitting module including a plurality of transmitting units for transmitting laser detection pulses
  • a detection module including a plurality of detection units, for receiving the echoes of the laser detection pulses reflected on the target, and converting the echoes into electrical signals;
  • sampling device converting the electrical signal into a digital signal
  • a processing device coupled to the sampling device, configured to determine detection data based on the digital signal, the detection data including time information and intensity information corresponding to the time information, and with a first time precision, according to the the weight of time information, and the intensity information is stored;
  • the first time precision is the time interval between any two adjacent first time scales, and is n times the time resolution of the detection data of the radar, where n>1;
  • the time information is associated with a time interval of at least one first time scale.
  • the lidar is configured to scan a field of view multiple times, wherein the processing device is configured to superimpose and store the intensity information obtained by the multiple scans with a first time precision.
  • the processing device is further configured to:
  • the processing device is further configured to:
  • the frontier time is:
  • the numerical value corresponding to the leading edge of the echo pulse is compared with a preset threshold value, and the time information corresponding to the numerical value whose intensity is equal to the preset threshold value is used as the leading edge time.
  • the plurality of transmitting units emit detection beams to different field of view ranges, and a plurality of the field of view ranges constitute the detection range of the lidar.
  • the detection unit comprises a Geiger mode based detection unit
  • the sampling device comprises a time-to-digital converter
  • each of the transmitting units sequentially emits a detection beam to a corresponding field of view, and when one of the transmitting units emits a detection beam, at least one detection unit corresponding to the field of view of the transmitting unit Activated to start probing.
  • the present invention also provides a computer-readable storage medium comprising computer-executable instructions stored thereon, the executable instructions, when executed by a processor, implement the storage method as described above.
  • Figure 1 shows the triggering of single-photon avalanche diodes during multiple detection scans of lidar
  • Fig. 2 shows the histogram formed after multiple scans are superimposed
  • Figure 3 shows a data storage method according to the prior art
  • FIG. 4 shows a method for storing detection data of a radar according to an embodiment of the present invention
  • FIG. 5 shows a detection unit of a lidar according to an embodiment of the present invention
  • FIG. 6 and 7 show a specific schematic diagram of a storage mode according to a preferred embodiment of the present invention.
  • FIG. 8 shows a schematic diagram of a storage effect according to an embodiment of the present invention.
  • FIG. 9 shows a schematic diagram of a memory allocation manner according to a preferred embodiment of the present invention.
  • FIG. 10 illustrates a data processing method that may be used for lidar in accordance with one embodiment of the present invention.
  • Figure 11 shows a block diagram of a lidar according to one embodiment of the present invention.
  • connection should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection: it can be a mechanical connection, an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction of two elements relation.
  • connection should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection: it can be a mechanical connection, an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction of two elements relation.
  • a first feature "on” or “under” a second feature may include direct contact between the first and second features, or may include the first and second features Not directly but through additional features between them.
  • the first feature being “above”, “over” and “above” the second feature includes that the first feature is directly above and diagonally above the second feature, or simply means that the first feature is level higher than the second feature.
  • the first feature “below”, “below” and “beneath” the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature has a lower level than the second feature.
  • each time scale of its time resolution needs to have a corresponding storage location, and all the triggered SPAD number information cnt obtained by multiple measurements are stored in the same time as the time.
  • the time resolution of the time-to-digital converter TDC can reach the order of picoseconds ps, so a register with a very large space is required.
  • SPAD can be triggered by a single photon to avalanche effect, so it is easily affected by ambient light noise; on the other hand, SPAD has low photon detection efficiency (PDE) for the commonly used detection light band of lidar, and the signal obtained by a single detection
  • PDE photon detection efficiency
  • the intensity is very weak, as shown in Figure 1, in a detection scan, only a few triggers may occur within the detection time window (two triggers in Figure 1), and it is impossible to distinguish whether it is an echo signal or ambient light noise.
  • the lidar can perform multiple repeated measurements during one detection of the same field of view (one measurement is called a sweep). , the number of repetitions can reach 400-500 times, or more or less), the results of multiple measurements or scans are accumulated to obtain a histogram, and the distance is measured from this, and then a point cloud on the lidar is obtained. point.
  • the controller of the lidar gates some (a row or column or any shape of interest) macro pixels by supplying high voltage to the SPAD, and then sends a synchronization signal to notify the laser at the transmitter that it can emit light, and the laser at the transmitter
  • a light pulse for detection is sent out.
  • the light pulse encounters an external obstacle, is reflected by the obstacle and returns to the lidar, and can be received by the photodetector at the receiving end. .
  • the photodetector is a SPAD(s) array
  • an avalanche electrical signal is generated, which is transmitted to the time-to-digital converter, and the time-to-digital converter outputs the time signal t 1a triggered by the SPAD and the SPAD triggered at the same time.
  • the number signal cnt 1a (here 1a represents the first trigger of the a-th scan)
  • the time stamp 1a (hereinafter referred to as tp 1a ) of t 1a -t a is calculated by the subtraction procedure
  • tp 1a and the time The number of triggers for stamping the cnt 1a signal is transmitted and stored in memory.
  • a macro pixel includes multiple SPADs, and SPADs can be detected again after the dead time, so in one scan, SPAD triggering may occur at another time, and the memory stores tp 2a and cnt 2a of this trigger (2a is Represents the 2nd trigger of the a-th probe). Multiple triggers in one scan need to be stored as time information.
  • the controller of the lidar sends a signal again according to the preset program to control the transmitting end to send out the detection light pulse at time t b .
  • the SPAD receives the photon
  • the avalanche electrical signal is transmitted to the time-to-digital converter TDC, and the time-to-digital converter TDC outputs the time signal t 1b triggered by the SPAD and the signal cnt 1b of the number of SPADs triggered at the same time (the b-th detection 1 trigger)
  • the subsequent memory stores the timestamp timestamp 1b (hereinafter referred to as tp 1b ) of the SPAD trigger time t 1b -t b and the trigger number cnt 1b signal of the timestamp.
  • a macro pixel includes multiple SPADs, and the SPADs can be detected again after the dead time, so in one scan, the SPAD may be triggered again at another time, and the memory stores tp 2b and cnt 2b of this trigger
  • the trigger number cnt obtained by each measurement is stored in the corresponding memory location according to the timestamp.
  • the original stored value is compared with The new trigger number cnt is accumulated and then updated to this position.
  • a histogram is saved in the memory. As shown in Figure 2, the histogram reflects the sum of the trigger numbers cnt corresponding to different timestamps on the time axis. In this way, the histogram is used to calculate the center of gravity or the frontier time and other operations to obtain the time information corresponding to the echo, which is used as the flight time for distance calculation to generate a point on the point cloud.
  • a data storage method is shown in Figure 3, the abscissa is time t, the scale interval of the abscissa is the resolution of TDC, and each time scale corresponds to a storage location R (register). For example, in a certain detection scan a, a SPAD trigger occurs at time scale 0. According to the transmission time and the trigger time of TDC transmission, the timestamp tp 1 (trigger time - the current transmission time) and the trigger number information cnt 1a are obtained by calculation, and cnt 1a is stored.
  • a represents the a-th detection
  • b is the b-th detection
  • the numbers represent the corresponding time scale and the corresponding storage location
  • the storage location R corresponds to the time scale one-to-one
  • the memory only stores the trigger number cnt
  • the data processing When the circuit reads the data, the time corresponding to the trigger number cnt can be known according to the storage location).
  • a histogram is obtained by accumulating the data of many detection scans (400-500 times), and the detection results of hundreds of scans are superimposed into a histogram to obtain a point in the point cloud.
  • the storage location corresponding to the time scale stores the accumulated sum of all the trigger quantities cnt triggered at this moment.
  • SPAD triggering does not occur at every time scale in a scan, as shown in Figure 3, a histogram data is superimposed by many detection results, and each time scale may occur at a certain scan A SPAD trigger occurs during the process, so that the memory receives the corresponding data.
  • each time scale needs to have a corresponding storage location, and all the trigger numbers cnt obtained from multiple measurements are stored in the storage location corresponding to the time.
  • the time interval of tp that is, the resolution of TDC
  • the rate is on the order of ps, requiring very large registers.
  • the inventor of the present application has conceived that it is not necessary to set a corresponding storage location for each time scale of the TDC time resolution.
  • the invention adopts the data storage method of weighted accumulation, compresses the original signal under the condition of keeping the ranging precision, and greatly reduces the storage space required for storing the histogram. Specifically, the weighted accumulation data storage method can reduce the total storage space to 1/10 of the original range.
  • the time precision of the stored intensity information in the present invention is the first time precision, and the first time precision may be n times the time resolution of the time-to-digital converter TDC.
  • the intensity information refers to the optical signal intensity information corresponding to the time information.
  • different parameters can be used to represent the optical signal intensity: for example, the detector is a SPAD array, and the SPAD that is triggered at the same time corresponding to the time information can be used.
  • the quantity is used as the intensity information; if the detector is SiPM, the output level/current intensity corresponding to the time information can be used to represent the optical signal intensity information.
  • FIG. 4 shows a storage method 100 of radar detection data according to an embodiment of the present invention
  • FIG. 5 shows a schematic diagram of a detection module according to a preferred embodiment of the present invention, wherein the detection module 22 of the lidar includes a plurality of
  • the detection unit uses a single-photon avalanche diode SPAD as a photodetector, and each detection unit includes a plurality of SPADs.
  • step S101 detection data is received, where the detection data includes time information and intensity information corresponding to the time information.
  • the detection module 22 includes a plurality of detection units, which are shown as detection units 221 - 1 , 221 - 2 and 221 - n in FIG. 5 .
  • each detection unit includes a plurality of (for example, 9 in the figure, may also be 3, 4, ..., specifically may include p, p is a positive integer ⁇ 1) unit
  • Photon avalanche diode SPAD the output end of the single-photon avalanche diode of each detection unit is connected to a time to digital converter (TDC), and the detection window of each detection unit (that is, the time period during which the SPAD can sense incident photons) ) is independently adjustable, that is, each detection unit can be independently controlled to be active (the SPAD is in Geiger mode, that is, a reverse bias voltage greater than the breakdown voltage is applied to the SPAD, so that the SPAD can receive photons when it receives photons.
  • TDC time to digital converter
  • each detection unit is coupled to a time-to-digital converter TDC, which can determine the time of arrival of the photons.
  • a data processing device (not shown) connected to the TDC can acquire the detection light emission time, determine the time difference between the photon arrival time and the detection light emission time, and store the result in the memory.
  • the time information in FIG. 4 is the time when one or more single-photon avalanche diodes SPAD in the macro pixel are triggered, and the intensity information is the single-photon avalanche diode SPAD that is triggered at the trigger time.
  • the number of photon avalanche diodes SPADs that is, the number of single-photon avalanche diodes SPADs that are triggered, characterizes the intensity of the optical signal.
  • the time information is the time stamp timestamp of the triggering of the single-photon avalanche diode SPAD, that is, the time difference t between the time t a emitted from the laser and the time t 1a when the single-photon avalanche diode SPAD is triggered 1a -t a .
  • the single-photon avalanche diode SPAD is used as an example for illustration.
  • Those skilled in the art can easily understand that the present invention is not limited to this, and other types of photodetectors can also be used, including but not limited to avalanche photodiode APD. , silicon photomultiplier tube SiPM, etc.
  • step S102 store the intensity information with a first time precision according to the weight of the time information; the first time precision is the time interval between any two adjacent first time scales, and is the n times the time resolution of the radar detection data, wherein n>1; the weight is associated with the time information and the time interval of at least one first time scale.
  • FIG. 6 and FIG. 7 show a specific schematic diagram of a storage manner according to a preferred embodiment of the present invention, and the implementation of step S102 will be described in detail below with reference to FIG. 6 and FIG. 7 .
  • the abscissa is the flight time
  • the interval of the time scale of the abscissa is, for example, the time resolution of the lidar, such as the time resolution of the time-to-digital converter TDC, which can reach the order of picoseconds ps.
  • the first time scale is set based on the time resolution of the lidar.
  • the interval between two adjacent first time scales spans 16 interval of the time resolution of the lidar.
  • Time x represents the time resolution of radar detection data where the time interval between the time and the first time scale A adjacent to the left of the time is x times.
  • the time scale corresponding to the time resolution of lidar can also be called “fine scale”. Also known as “coarse scale”.
  • the weight of the time x includes a first weight and a second weight
  • the first weight is associated with the time interval between the time x and one of the adjacent first time scales
  • the second weight Associated with the time interval between said instant x and another adjacent first time scale.
  • the first weight is associated with the time interval between the moment x and the first time scale A adjacent to the left thereof, and the first weight is, for example, (16-x)
  • the second weight is associated with the time interval between the moment x and the first time scale A+1 adjacent to the right side thereof, and the second weight is, for example, x. Therefore, the moment x is represented by its weight at two adjacent coarse scales (A, A+1), where the weight of x at coarse scale A is (16-x), and at coarse scale A+
  • the weight of 1 is x (x represents the distance from A at this moment), which is equivalent to the fine scale of x at this moment.
  • the data at the fine scale is stored at the addresses corresponding to two adjacent thick scales to represent the value of the scale x, rather than storing the scale x itself. This process is represented by the equation as follows:
  • the left side of the equal sign is the sum of the weights applied according to the coarse scale storage, the start value and the end value of the coarse scale, and the right side of the equal sign is the specific value of the timestamp.
  • the storage method of coarse scale + weight can represent the specific value of the timestamp.
  • the newly added intensity information on the coarse scale A is cnt*(16-x), and the coarse scale A+1
  • the newly added intensity information is cnt*x, which can be accumulated separately in multiple scans.
  • the fine scale represents the time-to-digital converter TDC time resolution. For a timestamp, the starting value of its coarse scale is A, and its fine scale is at the 0-15 fine scale x scale corresponding to its coarse scale.
  • a register is allocated for each coarse scale, the coarse scale interval of the abscissa is 16 times the TDC resolution, and each coarse scale corresponds to a register.
  • a coarse scale time fine scale 0 to 15
  • all trigger quantity information cnt is weighted, and stored in the registers corresponding to storage positions A and A+1 after summing with the original data.
  • the trigger quantity information cnt in the next coarse scale time is weighted and stored in the registers corresponding to the coarse scales A+1 and A+2. For example, when a SPAD trigger occurs at time 2', the time information tp 3 ' and cnt 3a ' are obtained.
  • the received signals tp 2 and cnt 2b are assigned weights cnt 2b *(16-x 2b ) and cnt 2b *x 2b on the coarse scale A and A+1 respectively, which are respectively the same as the original stored data.
  • After the summation is stored in the registers corresponding to the coarse scale A and A+1.
  • a histogram is obtained by accumulating the data of many scans. In several scans, all the trigger numbers cnt corresponding to the triggers at times 0 to 15 are stored in the registers corresponding to the coarse scales A and A+1.
  • the comparative relationship between the coarse scale and the fine scale is shown in Figure 8.
  • the present invention adopts the weighted accumulation storage method, and only needs to be 0 ⁇ n+ in Figure 8.
  • the coarse scale of 1 corresponds to the setting register, and the number of registers required is reduced to 1/16 of the original.
  • the storage bit width of each register increases and the space occupied becomes larger, because the storage location to be allocated is greatly reduced, the weighted accumulation
  • the data storage method can reduce the total storage space to 1/10 of the original range.
  • the time interval between adjacent first time scales is 16 times the time resolution (fine scale) of radar detection data, that is, data compression is performed with a weight of 16.
  • the weight here may be any large positive integer, preferably 2 m , where m is a positive integer, so as to facilitate implementation in FPGA or ASIC.
  • the first weight is (16-x), the second weight is x, the present invention is not limited to this, the first weight may be x, and the second weight is (16-x ), or the first weight may be 1-(x/n), and the second preset weight may be x/n, as long as the first weight is equal to the time x and one of the adjacent first time scales
  • the second weight may be associated with the time interval between the moment x and another adjacent first time scale.
  • the distance measurement accuracy can be maintained while reducing the storage space. Details are described below.
  • the data is stored with a 4-bit bit width (that is, 16 fine scales form a coarse scale), and the echo arrival time is calculated by the center of gravity method.
  • 16 time fine scales into a coarse scale, and then record the number of photons arriving on the kth fine scale on the coarse scale from n to n+1 as In this way, the barycentric formula of the number of photons on the fine coordinate scales on all fine scales in 0-n+1 coarse scales can be obtained:
  • G0 represents the arrival time of the echo calculated by the centroid method when stored in binary.
  • the corresponding weight value Bi allocated on the i-th rough scale is as follows:
  • G1 represents the echo arrival time calculated by the center of gravity method when the weighted accumulation method of the present invention is used for data storage. Put the molecules of the above formula according to Errors are merged to get
  • the data stored in the register corresponding to the coarse scale of the present invention is the sum of the values after weighting the trigger number cnt in the left and right intervals of the coarse scale.
  • the value of the noise outside the signal is not very large, and the bit width of the stored noise does not need to be consistent with the bit width of the stored signal.
  • the number of register bits may require a memory bit width of 16 bits, but the storage noise may only require a memory bit width of 8 bits.
  • the storage method further includes: when it is judged that one of the storage units overflows or is about to overflow, assigning another storage address to the storage unit from the reserved register.
  • the reserved registers include N groups of registers, where N is a preset value, and each group of registers is used for a storage unit that overflows or is about to overflow.
  • M is determined according to the maximum value of the stored data. For example, for registers that originally require a maximum of 16 bits, 32 8-bit registers can be set as a group of reserved registers.
  • the intensity information in the detected data will be stored with the first time precision and according to the weight of the time information.
  • a histogram can be formed, and the histogram can be used , and calculate the center on the time axis to obtain a more accurate echo pulse position and flight time.
  • the present invention also provides a data processing method, wherein the data is stored in a storage unit of a memory by the above-mentioned storage method 100, and the processing method includes:
  • the time axis coordinates (eg, the coordinates of the fine scale) corresponding to the center of gravity can be used as the flight time of the echo pulse to calculate the distance to the target.
  • the processing method includes:
  • the value stored in the storage unit corresponding to each first time scale is read; the leading edge time of the echo pulse is obtained. Specifically, the value corresponding to the leading edge of the echo pulse is compared with a preset threshold, and the time information corresponding to the numerical value whose intensity is equal to the preset threshold is used as the leading edge time for calculating the distance to the target.
  • the preset threshold is a noise threshold.
  • the preset threshold is the average value of the noise threshold and the pulse peak value.
  • the present invention also provides a data processing method 200 that can be used for lidar, as shown in FIG. 10 , including:
  • step S201 the receiving time and intensity information of the echo are received.
  • the receiving unit 22 shown in FIG. 5 is used to receive the echo of the lidar, and the receiving moment is the moment when the single-photon avalanche diode SPAD in each macro pixel is triggered, and the intensity information can be triggered by this moment. Characterized by the number of single-photon avalanche diodes.
  • step S202 determining time information based on the transmission moment of the probe pulse and the reception moment.
  • the time difference that is, the flight time of the echo, can be obtained and used as time information.
  • step S203 store the intensity information with a first time precision and according to the weight of the time information; wherein, the first time precision is the time interval between any two adjacent first time scales, and is n times the time resolution of the radar detection data, where n>1; the weight is associated with the time information and the time interval of at least one first time scale.
  • the weight of the time information stores the strength information, which is not repeated here.
  • the lidar when the lidar detects a field of view (for example, a part in a three-dimensional environment), the field of view is scanned multiple times, and the detection information is obtained according to the detection information of the multiple scans. distance information for the site.
  • the step S203 includes: superimposing and storing the intensity information obtained by the multiple scans with the first time precision.
  • the value stored in the storage unit corresponding to each first time scale is read; the leading edge time of the echo pulse is obtained. Specifically, the value corresponding to the leading edge of the echo pulse is compared with a preset threshold, and the time information corresponding to the numerical value whose intensity is equal to the preset threshold is used as the leading edge time.
  • the preset threshold is a noise threshold.
  • the preset threshold is the average value of the noise threshold and the pulse peak value.
  • the present invention also provides a laser radar 20, as shown in FIG. 11 .
  • the lidar 20 includes a transmitting module 21 , a detection module 22 , a sampling device 23 and a processing device 24 .
  • the transmitting module 21 includes a plurality of transmitting units (eg, a plurality of lasers), which are used for transmitting laser detection pulses L into the three-dimensional environment to detect the target object.
  • the detection module 22 includes a plurality of detection units for receiving echoes L' of the laser detection pulses L reflected on the target, and converting the echoes into electrical signals.
  • the detection module 22 can be, for example, the detection module 22 shown in FIG. 5 , including a plurality of detection units composed of single-photon avalanche diodes SPAD.
  • the sampling device converts the electrical signal into a digital signal, and/or the arrival times of the echoes can be obtained.
  • the sampling device may include an analog-to-digital converter ADC and a time-to-digital converter TDC.
  • the processing device 24 is coupled to the sampling device 23, and can also be coupled to the transmitting unit 21 at the same time, and is configured to determine detection data according to the digital signal, where the detection data includes time information and a data corresponding to the time information.
  • the intensity information and store the intensity information according to the weight of the time information with the first time precision; wherein, the first time precision is the time interval between any two adjacent first time scales, and is n times the time resolution of the radar detection data, where n>1; the weight is associated with the time information and the time interval of at least one first time scale.
  • the lidar is configured to scan a field of view multiple times, wherein the processing device is configured to superimpose and store the intensity information obtained by the multiple scans with a first time precision.
  • the processing device is further configured to: after completing the multiple scans, read the value stored in the storage unit corresponding to each first time scale; calculate the value on the time axis the center of gravity; take the time information corresponding to the center of gravity as the flight time.
  • the processing device is further configured to: after completing the multiple scans, read the value stored in the storage unit corresponding to each first time scale; obtain the leading edge time of the echo pulse . Specifically, the value corresponding to the leading edge of the echo pulse is compared with a preset threshold, and the time information corresponding to the numerical value whose intensity is equal to the preset threshold is used as the leading edge time.
  • the preset threshold is a noise threshold.
  • the preset threshold is the average value of the noise threshold and the pulse peak value.
  • the multiple emission units correspond to different field of view ranges, that is, emit detection beams to different field of view ranges, and a plurality of the field of view ranges constitute the detection range of the lidar.
  • each of the emitting units sequentially emits a detection beam to a corresponding field of view, and when one of the emission units emits a detection beam, at least one detection beam corresponding to the field of view of the emission unit detects The unit is activated to start probing.
  • the present invention also relates to a computer-readable storage medium comprising computer-executable instructions stored thereon which, when executed by a processor, implement the storage method 100 as described above.

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Abstract

一种雷达的探测数据的存储方法、用于激光雷达的数据处理方法、激光雷达及计算机可读存储介质，该存储方法包括：S101：接收探测数据，该探测数据包括时间信息和与时间信息对应的强度信息；S102：以第一时间精度，按照时间信息的权重，存储强度信息；其中，第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为雷达的探测数据的时间分辨率的n倍,其中n>1；该权重与时间信息和至少一个第一时间刻度的时间间隔相关联。该存储方法在减小存储空间的同时能够保持测距精度。

Description

存储方法、数据处理方法、激光雷达和计算机可读存储介质 技术领域
本公开大致涉及光电探测技术领域，尤其涉及雷达的探测数据的存储方法、数据处理方法、激光雷达和计算机可读存储介质。
背景技术
激光雷达是以发射激光束来探测目标的位置、速度等特征量的雷达系统，是一种将激光技术与光电探测技术相结合的先进探测方式。激光雷达因其分辨率高、隐蔽性好、抗有源干扰能力强、低空探测性能好、体积小及重量轻等优势，被广泛应用于自动驾驶、交通通讯、无人机、智能机器人、资源勘探等领域。
激光雷达中通常时间数字转换器来获得时间信息，包括回波的到达时间和/或回波的飞行时间。使用基于高精度时间数字转换器(time to digital converter，TDC)测量系统中，将每一次测量得到的时间信息累积为直方图，消耗极大的存储空间。一些激光雷达采用类似单光子雪崩二极管(single photon avalanche diode，SPAD)作为探测器，SPAD可被单光子触发雪崩，TDC可以对每次触发的时刻timestamp给出皮秒级精度的测量。某些应用中，多个SPAD的输出端连接到同一TDC，作为一个宏像素(pixel)，TDC在提供触发时刻timestamp的同时，给出该宏像素内同时触发的SPAD个数cnt。
采用现有的存储和测距方法，由于触发时刻timestamp的精度单位为ps量级，需要较长tof探测时，要存储一个完整的直方图需要消耗极大的存储器，消耗极大的存储空间。特别是为了提高测远能力，需要增大测量的时长和重复测量次数，对存储空间的要求也不断增大。
背景技术部分的内容仅仅是公开人所知晓的技术，并不当然代表本领域的现有技术。
发明内容
有鉴于现有技术的至少一个缺陷，本发明提供一种雷达的探测数据的存储方法，包括：
S101：接收探测数据，所述探测数据包括时间信息和与所述时间信息对应的强度信息；和
S102：以第一时间精度，按照所述时间信息的权重，存储所述强度信息；
其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；
所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
根据本发明的一个方面，所述权重包括第一权重和第二权重，所述第一权重与所述时间信息和其中一个相邻的第一时间刻度之间的时间间隔相关联，所述第二权重与所述时间信息与另一个相邻的第一时间刻度之间的时间间隔相关联，所述步骤S102包括：以第一时间精度，分别按照所述第一权重和第二权重，存储所述强度信息。
根据本发明的一个方面，所述第一权重为n-x，所述第二权重为x，其中x表示所述时间信息与相邻的第一时间刻度的时间间隔为x倍的雷达探测数据时间分辨率。
根据本发明的一个方面，所述第一权重为所述时间信息对应其左侧相邻的第一时间刻度的权重，所述第二权重为所述时间信息对应其右侧相邻的第一时间刻度的权重，其中x表示所述时间信息与其左侧相邻的第一时间刻度的时间间隔为x倍的雷达探测数据时间分辨率。
根据本发明的一个方面，所述第一权重为1-(x/n)，所述第二预设权重为x/n，其中x表示所述时间信息与其左侧相邻的第一时间刻度的时间间隔为x倍的雷达探测数据时间分辨率。
根据本发明的一个方面，n＝2 m，m为正整数。
根据本发明的一个方面，所述强度信息包括探测单元的触发数量。
根据本发明的一个方面，存储器中具有与每个第一时间刻度对应的存储单元，所述步骤S102包括：按照第一权重和第二权重，将所述强度信息存储在与所述时间信息相邻的两个第一时间刻度相对应的两个存储单元中。
根据本发明的一个方面，所述步骤S102还包括：当向其中一个存储单元按照所述权重存入所述强度信息时，
读取所述存储单元中存储的数值；
将所述强度信息根据所述权重计算的数值与所读取的数值累加；和
将累加的结果写入所述存储单元中。
根据本发明的一个方面，所述存储方法还包括：当判断其中一个存储单元发生溢出或者将要发生溢出时，从预留寄存器中为所述存储单元分配另外的存储地址。
根据本发明的一个方面，所述预留寄存器包括N组寄存器，其中N为预设值，每组寄存器用于一个发生溢出或将要发生溢出的存储单元。
本发明还提供一种可用于激光雷达的数据处理方法，包括：
S201：获取光信号的接收时刻以及强度信息；
S202：基于探测脉冲的发射时刻和所述接收时刻确定时间信息；
S203：以第一时间精度，按照所述时间信息的权重，存储所述强度信息；
其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；
所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
根据本发明的一个方面，所述激光雷达对一个视场范围进行多次扫描，其中所述步骤S203包括：以第一时间精度，将所述多次扫描获得的强度信息叠加存储。
根据本发明的一个方面，所述数据处理方法还包括：
完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；
计算所述数值在时间轴上的重心；
将所述重心作为飞行时间。
根据本发明的一个方面，所述数据处理方法还包括：
完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值，获取回波脉冲的前沿时间；
其中，所述前沿时间为：
比较对应所述回波脉冲前沿的所述数值与预设阈值，将强度等于预设阈值的所述数值对应的时间信息作为所述前沿时间。
本发明还提供一种激光雷达，包括：
发射模块，包括多个发射单元，用于发射激光探测脉冲；
探测模块，包括多个探测单元，用于接收所述激光探测脉冲在目标物上反射后的回波，并将所述回波转换为电信号；
采样装置；将所述电信号转换为数字信号；
处理装置，与所述采样装置耦接，配置成根据所述数字信号确定探测数据，所述探测数据包括时间信息和与所述时间信息对应的强度信息，并以第一时间精度，按照所述时间信息的权重，存储所述强度信息；
其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
根据本发明的一个方面，所述激光雷达配置成对一个视场范围进行多次扫描，其中所述处理装置配置成以第一时间精度，将所述多次扫描获得的强度信息叠加存储。
根据本发明的一个方面，所述处理装置进一步配置成：
完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；
计算所述数值在时间轴上的重心；
将所述重心作为飞行时间。
根据本发明的一个方面，所述处理装置进一步配置成：
完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值，获取回波脉冲的前沿时间；
其中，所述前沿时间为：
比较对应所述回波脉冲前沿的所述数值与预设阈值，将强度等于预设阈值的所述数值对应的时间信息作为所述前沿时间。
根据本发明的一个方面，所述多个发射单元发射探测光束至不同的视场范围，多个所述视场范围组成所述激光雷达的探测范围。
根据本发明的一个方面，所述探测单元包括基于盖革模式的探测单元，所述采样装置包括时间数字转换器。
根据本发明的一个方面，每个所述发射单元依次发出探测光束至相应的视场范围，当其中一个发射单元发出探测光束后，与该发射单元的视场范围相对应的的至少一个探测单元被激活开始探测。
本发明还提供一种计算机可读存储介质,包括存储于其上的计算机可执行指令，所述可执行指令在被处理器执行时实施如上所述的存储方法。
附图说明
构成本公开的一部分的附图用来提供对本公开的进一步理解，本公开的示意性实施例及其说明用于解释本公开，并不构成对本公开的不当限定。在附图中：
图1示出了激光雷达多次探测扫描过程中单光子雪崩二极管的触发；
图2示出了多次扫描叠加后形成的直方图；
图3示出了根据现有技术的数据存储方法；
图4示出了根据本发明一个实施例的雷达的探测数据的存储方法；
图5示出了根据本发明一个实施例的激光雷达的探测单元；
图6和图7示出了根据本发明一个优选实施例的存储方式的具体示意图；
图8示出了根据本发明实施例的存储效果示意图；
图9示出了根据本发明一个优选实施例的存储器分配方式的示意图；
图10示出了根据本发明一个实施例的可用于激光雷达的数据处理方法；和
图11示出了根据本发明一个实施例的激光雷达的框图。
具体实施方式
在下文中，仅简单地描述了某些示例性实施例。正如本领域技术人员可认识到的那样，在不脱离本发明的精神或范围的情况下，可通过各种不同方式修改所描述的实施例。因此，附图和描述被认为本质上是示例性的而非限制性的。
在本发明的描述中，需要理解的是，术语"中心"、"纵向"、"横向"、"长度"、"宽度"、"厚度"、"上"、"下"、"前"、"后"、"左"、"右"、"竖直"、"水平"、"顶"、"底"、"内"、"外"、"顺时针"、"逆时针"等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。此外，术语"第一"、"第二"仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有"第一"、"第二"的特征可以明示或者隐含地包括一个或者更多个所述特征。在本发明的描述中，"多个"的含义是两个或两个以上，除非另有明确具体的限定。
在本发明的描述中，需要说明的是，除非另有明确的规定和限定，术语"安装"、"相连"、"连接"应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接:可以是机械连接，也可以是电连接或可以相互通讯；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本发明中的具体含义。
在本发明中，除非另有明确的规定和限定，第一特征在第二特征之"上"或之"下"可以包括第一和第二特征直接接触，也可以包括第一和第二特征不 是直接接触而是通过它们之间的另外的特征接触。而且，第一特征在第二特征"之上"、"上方"和"上面"包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征"之下"、"下方"和"下面"包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度小于第二特征。
下文的公开提供了许多不同的实施方式或例子用来实现本发明的不同结构。为了简化本发明的公开，下文中对特定例子的部件和设置进行描述。当然，它们仅仅为示例，并且目的不在于限制本发明。此外，本发明可以在不同例子中重复参考数字和/或参考字母，这种重复是为了简化和清楚的目的，其本身不指示所讨论各种实施方式和/或设置之间的关系。此外，本发明提供了的各种特定的工艺和材料的例子，但是本领域普通技术人员可以意识到其他工艺的应用和/或其他材料的使用。
以下结合附图对本发明的优选实施例进行说明，应当理解，此处所描述的优选实施例仅用于说明和解释本发明，并不用于限定本发明。
在一些激光雷达的时间数字转换器中，在其时间分辨率的每个时间刻度都需要有一个对应的存储位置，多次测量获得的所有的触发的SPAD个数信息cnt均存储在与时刻相对应的存储位置内，而时间数字转换器TDC的时间分辨率能够达到皮秒ps的量级，因此需要非常大空间的寄存器。具体解释如下。
SPAD可被单个光子触发雪崩效应，因此容易受到环境光噪声的影响；另一方面，SPAD对于激光雷达常用探测光波段的光子探测效率(photon detection efficiency，PDE)较低，单次探测获得的信号强度很弱，如图1所示，一次探测扫描中，可能在探测时间窗口内只发生了几次触发(图1中为两次触发)，无法区分是回波信号还是环境光噪声。为了提高激光雷达的测远性能并且降低噪声的影响，如图1所示，激光雷达在对同一视场范围的一次探测过程中，可以进行多次重复测量(一次测量称为一次扫描(sweep)，重复次数可达400-500次，也可以更多次或更少次)，多次测量或扫描的结果累积得到一个直方图，并以此测得距离，进而获得激光雷达点云上的一个 点。
对于一次扫描而言，激光雷达的控制器通过给SPAD供应高压的方式来选通部分(一行或一列或任意感兴趣的形状)宏像素，然后发送同步信号通知发射端的激光器可以发光，发射端的激光器于时刻t a(a表示第a次扫描)发出用以探测的光脉冲，该光脉冲遇到外界的障碍物，被障碍物所反射且回到激光雷达，可被接收端的光电探测器所接收。当光电探测器为SPAD(s)阵列时，一旦SPAD接收到光子，产生雪崩电信号，传输至时间数字转换器，由时间数字转换器输出SPAD触发的时间信号t 1a以及同一时刻被触发的SPAD的数量信号cnt 1a(此处1a即表示第a次扫描的第1次触发)，经过相减程序计算t 1a-t a的时间戳timestamp 1a(以下简称tp 1a)，将tp 1a和该时间戳的触发数量cnt 1a信号传输并存储在存储器中。一个宏像素内包括多个SPAD，且SPAD在死时间之后可以再次探测，所以在一次扫描中，可能在另一时刻又发生了SPAD触发，存储器存储这一次触发的tp 2a和cnt 2a(2a即表示第a次探测的第2次触发)。一次扫描中的多次触发均需要按时间信息进行存储。
在下一次扫描b，激光雷达的控制器按照预设程序，再次发送信号控制发射端于t b时刻发出探测光脉冲。一旦SPAD接收到光子，雪崩电信号传输至时间数字转换器TDC，由时间数字转换器TDC输出SPAD触发的时间信号t 1b以及同一时刻被触发的SPAD的数量信号cnt 1b(第b次探测的第1次触发)，后续的存储器存储SPAD触发时间t 1b-t b的时间戳timestamp 1b(以下简称tp 1b)和该时间戳的触发数量cnt 1b信号。一个宏像素内包括多个SPAD，且SPAD在死时间之后可以再次探测，所以在一次扫描中，可能在另一时刻又发生了SPAD触发，存储器存储这一次触发的tp 2b和cnt 2b。
几百次测量中，将每次测量得到的触发数量cnt根据时间戳timestamp存入相应的存储器位置中，当同样时间戳timestamp对应位置处有新的触发数量cnt到达时，将原来存储的值与新的触发数量cnt累加然后更新到该位置，多次扫描叠加后存储器内即保存了一个直方图，如图2所示，直方图反映了时间轴上不同时间戳timestamp对应的触发数量cnt总和，这样使用直 方图计算重心或前沿时间等操作获得回波对应的时间信息，作为用于距离计算的飞行时间，生成点云上的一个点。
一种数据存储方法如图3所示，横坐标为时间t，横坐标的刻度间隔为TDC的分辨率，每一时间刻度对应一个存储位置R(寄存器)。比如某一次探测扫描a，在时间刻度0发生SPAD触发，根据发射时间和TDC传输的触发时间计算获得时间戳tp 1(触发时间-本次发射时间)和触发数量信息cnt 1a，将cnt 1a存储在tp 1时刻对应的存储位置R1；在时间刻度4如果发生了SPAD触发，获得时间信息tp 5和cnt 5a，将cn 5a存储在tp 5对应的存储位置R5。在另一次探测扫描b，在时间刻度4也发生了SPAD触发，获得时间信息tp 5和cnt 5b，cnt 5b也对应存储位置R5，此时将cnt 5a读出，再将cnt 5b与cnt 5a相加的值更新到R5。(结合图3，a表示第a次探测，b即第b次探测，数字表示对应的时间刻度和相应的存储位置；存储位置R与时间刻度一一对应，存储器只存储触发数量cnt，数据处理电路读取数据时根据存储位置即可获知触发数量cnt对应的时间)。
参考图3可知，一个直方图由很多次探测扫描(400-500次)的数据累加获得，在几百次扫描的探测结果叠加成一个直方图，获得点云中一个点的过程中，某一时间刻度对应的存储位置存储的是该时刻发生触发的所有触发数量cnt累加的和。虽然一次扫描中并不会在每个时间刻度处都发生SPAD触发，但如图3所示，一个直方图数据是由很多次探测结果叠加的，每一个时间刻度处都有可能在某一次扫描过程中发生SPAD触发，使存储器收到对应的数据。因此，对于一个TDC，每个时间刻度都需要有一个对应的存储位置，多次测量获得的所有的触发数量cnt均存储在与时刻相对应的存储位置内，tp的时间间隔、即TDC的分辨率达到ps量级，需要非常大空间的寄存器。
采用这样的存储和测距方法，由于时间戳timestamp的精度单位为ps量级，需要较长tof探测时，要存储一个完整的直方图需要消耗极大的存储器，消耗极大的存储空间。特别是为了提高测远能力，需要增大测量的时长和重复测量次数，对存储空间的要求也不断增大。
本申请的发明人构思出，不必对于TDC时间分辨率的每个时间刻度都设置对应的存储位置，在存储探测数据时，不按照时间分辨率来存储，而是以更低的时间精度，按照时间信息的权重来存储强度信息。本发明采用加权累加的数据存储方法，在保留测距精度的情况下对原始信号做压缩，极大地减少存储直方图所需的存储空间。具体的，加权累加的数据存储方法可将总的存储空间减小到原来的1/10范围。
具体的，本发明存储强度信息的时间精度为第一时间精度，第一时间精度可以为时间数字转换器TDC时间分辨率的n倍。所述强度信息，指的是对应时间信息的光信号强度信息，对于不同的光电探测器，可用不同的参数表征光信号强度：例如探测器为SPAD阵列，可采用对应时间信息的同时触发的SPAD数量作为强度信息；若探测器为SiPM，可采用对应时间信息的输出电平/电流强度表示光信号强度信息。
下面参考附图详细描述。
图4示出了根据本发明一个实施例的雷达的探测数据的存储方法100，图5示出了根据本发明的一个优选实施例的探测模块的示意图，其中激光雷达的探测模块22包括多个探测单元，使用单光子雪崩二极管SPAD作为光电探测器，每个探测单元包括多个SPAD。
如图4所示，在步骤S101，接收探测数据，所述探测数据包括时间信息和与所述时间信息对应的强度信息。
如图5所示，探测模块22包括多个探测单元，在图5中示为探测单元221-1、221-2以及221-n。在图5的实施例中，每个探测单元包括多个(比如图示的9个，也可以为3个、4个、……，具体可以包括p个，p为≥1的正整数)单光子雪崩二极管SPAD，每个探测单元的单光子雪崩二极管的输出端连接到时间数字转换器(time to digital converter,TDC)，每个探测单元的探测窗口(即SPAD能够感测入射光子的时间段)的范围独立可调，即可以独立地控制每个探测单元处于激活状态(SPAD处于盖革模式下，即在SPAD上施加大于击穿电压的反向偏压，使得SPAD在接收到光子时能够触发 雪崩效应)或者去激活状态(无法被光子触发雪崩的状态)。光子入射到探测单元221-1、221-2以及221-n上之后，触发单光子雪崩二极管SPAD并产生电信号。每个探测单元耦接到时间数字转换器TDC，时间数字转换器TDC可以确定光子的到达时间。TDC连接的数据处理装置(图未示)可以获取探测光发射时间，确定光子到达时间与探测光发射时间的时间差，并将结果存储在存储器中。
以图5所示的探测单元为例，图4中的所述时间信息为宏像素中一个或多个单光子雪崩二极管SPAD被触发的时间，所述强度信息为在该触发时间被触发的单光子雪崩二极管SPAD的数量，即通过被触发的单光子雪崩二极管SPAD的数量来表征光信号的强度。根据本发明的一个优选实施例，所述时间信息为触发单光子雪崩二极管SPAD的时间戳timestamp，即从激光器发射的时间t a与单光子雪崩二极管SPAD被触发的时间t 1a之间的时间差t 1a-t a。
图5的实施例中，以单光子雪崩二极管SPAD为例进行了说明，本领域技术人员容易理解，本发明不限于此，也可以采用其他类型的光电探测器，包括但不限于雪崩光电二极管APD、硅光电倍增管SiPM等。
在步骤S102：以第一时间精度，按照所述时间信息的权重，存储所述强度信息；所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
图6和图7示出了根据本发明一个优选实施例的存储方式的具体示意图，下面参考图6和图7详细描述步骤S102的实施。
图6中，横坐标为飞行时间，横坐标的时间刻度的间隔例如为激光雷达的时间分辨率，例如时间数字转换器TDC的时间分辨率，可达到皮秒ps的量级。如图6所示，在激光雷达的时间分辨率的基础上设置了第一时间刻度，如图6中的A和A+1所示，相邻的两个第一时间刻度之间跨过16个所述激光雷达的时间分辨率的间隔。当在时刻x处探测到光子时(例如5所示的接收单元22中的一个宏像素中一个或多个单光子雪崩二极管SPAD被触发)，按 照所述时刻x的权重来存储探测到的强度值。时刻x表示所述该时刻与其左侧相邻的第一时间刻度A的时间间隔为x倍的雷达探测数据时间分辨率。
本领域技术人员容易理解，由于激光雷达的时间分辨率较小，第一时间刻度的间隔较大，因此对应于激光雷达时间分辨率的时间刻度也可称为“细刻度”，第一时间刻度也可称为“粗刻度”。
如图6所示，所述时刻x的权重包括第一权重和第二权重，第一权重与所述时刻x和其中一个相邻的第一时间刻度之间的时间间隔相关联，第二权重与所述时刻x与另一个相邻的第一时间刻度之间的时间间隔相关联。确定了第一权重和第二权重之后，以第一时间精度，分别按照所述第一权重和第二权重，存储所述强度信息。
根据本发明的一个优选实施例，所述第一权重与所述时刻x和其左侧相邻的第一时间刻度A之间的时间间隔相关联，第一权重例如为(16-x)，所述第二权重为所述时刻x和其右侧相邻的第一时间刻度A+1之间的时间间隔相关联，第二权重例如为x。因此，将时刻x用其在相邻的两个粗刻度(A,A+1)处的权重来替代表示，其中x在粗刻度A处的权重为(16-x)，在粗刻度A+1的权重为x(x表征该时刻距离A的距离)，以此来等效该时刻x的细刻度。换言之，通过将x作为权重，将细刻度处的数据存储到相邻两个粗刻度对应地址上，来表示刻度x的数值，而非存储刻度x本身。这个过程用等式表示如下：
A*(16-x)+(A+1)*x＝A*16+x
式中，等号左边为按照粗刻度存储、粗刻度起始值和结束值施加权重的和，等号右边为时间戳的具体值。用粗刻度+权重的存储方法能够表征时间戳的具体值。
类似的，当触发得到的信号除了时间戳还包括表示触发的数目或者强度等信息的触发数量cnt时，粗刻度A上新增的强度信息为cnt*(16-x)，粗刻度A+1上新增的强度信息为cnt*x，在多次扫描中分别进行累加即可。参考图7进行详细描述。细刻度表示时间数字转换器TDC时间分辨率。对于某个 时间戳timestamp，其粗刻度的起始值为A，其细刻度在其粗刻度中对应的0-15细标尺x刻度处。
参考图7，为每一个粗刻度分配了一个寄存器，横坐标的粗刻度间隔为16倍的TDC分辨率，每一粗刻度对应一个寄存器。在某一次扫描a过程中，在时间刻度0处发生了SPAD触发，获得时间信息tp 1(对应的x 1a＝0)和触发数量信息cnt 1a，分别在粗刻度A对应的寄存器A存储cnt 1a*(16-x 1a)，在粗刻度A+1对应的寄存器A+1存储cnt 1a*x 1a；在另一时间刻度5，获得时间信息tp 6(对应的x6 a＝5)和触发数量信息cnt 6a，将在粗刻度A对应的寄存器A内存储的数据读出，加上cnt 6a*(16-x 6a)后再存储在寄存器A；将粗刻度A+1对应的寄存器A+1的数据读出，加上cnt 6a*x 6a后重新存储在寄存器A+1。一个粗刻度时间(细刻度0～15)内，所有的触发数量信息cnt均施加权重，与原有数据求和后存储在存储位置A和A+1对应的寄存器内。下一个粗刻度时间内的触发数量信息cnt施加权重后存储在粗刻度A+1和A+2对应的寄存器中，例如时刻2’处发生了SPAD触发，获得时间信息tp 3’和cnt 3a’，则在粗刻度A+1对应的寄存器A+1内存储的数据加上cnt 3a’*(16-x 3a’)，在粗刻度A+2对应的寄存器A+2内存储cnt 3a’*x 3a’。
下一次扫描b的过程中，收到的信号tp 2和cnt 2b，分别在粗刻度A和A+1分配权重cnt 2b*(16-x 2b)和cnt 2b*x 2b，分别与原存储数据求和后存储在粗刻度A和A+1对应的寄存器中。一个直方图由很多次扫描的数据累加获得，若干次扫描中，在时刻0～15对应发生触发的所有触发数量cnt均在粗刻度A和A+1对应的寄存器中进行存储。
粗刻度与细刻度的对比关系如图8所示，相对于每个细刻度处都需要一个寄存器进行数据存储的方案，本发明采用了加权累加存储方法，只需要在图8中0～n+1的粗刻度对应设置寄存器，所需要的寄存器数量缩减到原来的1/16，虽然每个寄存器存储的位宽增大，占用的空间变大，但因为需要分配的存储位置大大减少，加权累加的数据存储方法可将总的存储空间减小到原来的1/10范围。
图6-8的实施例中，相邻的第一时间刻度(粗刻度)的时间间隔为雷达探测数据时间分辨率(细刻度)的16倍，即使用16为权重进行数据压缩。本领域技术人员容易理解，本发明不限于此，这里权重可以是任何较大的正整数，优选为2 m，m为正整数，从而便于在FPGA或者ASIC中实现。
上述实施例中，所述第一权重为(16-x)，所述第二权重为x，本发明不限于此，所述第一权重可以为x，所述第二权重为(16-x)，或者所述第一权重可以为1-(x/n)，所述第二预设权重为x/n，只要第一权重与所述时刻x和其中一个相邻的第一时间刻度之间的时间间隔相关联、第二权重与所述时刻x与另一个相邻的第一时间刻度之间的时间间隔相关联即可。
通过本发明的数据存储方法，在减小存储空间的同时仍能保持测距精度。下面详细说明。
以图6和图8的为例，以4bit位宽进行存储(即16个细刻度构成一个粗刻度)，采用重心法计算回波到达时间。将16个时间细刻度积累成一个粗刻度，然后给n～n+1的粗刻度上第k个细刻度上到达的光子数记作
Figure PCTCN2021138329-appb-000001
这样可以得到0-n+1个粗刻度内所有细刻度上光子数在细坐标刻度上的重心公式：
Figure PCTCN2021138329-appb-000002
G0表示以二进制存储时，采用重心法计算得到的回波到达时间。
通过使用上述的存储方法100对光子的时间信息和强度信息使用加权累加进行压缩存储后，对应第i个粗刻度上分配到的权重值Bi如下：
在i>0且i<n+1时，
Figure PCTCN2021138329-appb-000003
Figure PCTCN2021138329-appb-000004
Figure PCTCN2021138329-appb-000005
加权累加后的重心公式为
Figure PCTCN2021138329-appb-000006
G1表示采用本发明的加权累加方法进行数据存储时，采用重心法计算得到的回波到达时间。将上式分子按照
Figure PCTCN2021138329-appb-000007
错项合并得到
Figure PCTCN2021138329-appb-000008
可以确认G1和G0的结果是一致的。类似的，使用前沿法测距的结果其精度也不会因为该压缩带来损失。
参考图7，本发明的粗刻度对应的寄存器中存储的数据，为粗刻度左右两个间隔内的触发数量cnt施加权重后的数值总和，在较强信号处其值会比 较大，但是回波信号外的噪声的值却不会很大，存储噪声的位宽不需要与存储信号的位宽一致。根据系统实际探测情况，寄存器位数可能需要16bit的存储器位宽，但是存储噪声可能只需要8bit的存储器位宽。
因此根据本发明的一个优选实施例，提出一种更加节省寄存器空间的方案，因为整个探测时间段内，回波脉冲所占的时间跨度很小，其他大部分位置都是噪声，每个粗刻度分配16bit的寄存器会造成一些空间的浪费。可以采用8bit的寄存器，如图9所示，噪声处用8bit的寄存器足够存储触发数量cnt，而回波脉冲因为触发数量cnt较大，超过8bit，就可能会造成bit位溢出。因此根据本发明的一个实施例，所述的存储方法还包括：当判断其中一个存储单元发生溢出或者将要发生溢出时，从预留寄存器中为所述存储单元分配另外的存储地址。根据要探测回波的数目来预留若干个8bit寄存器，分为N组，每组M个(共M*N个寄存器)，在累计直方图的过程中一旦发现bit位溢出，给该寄存器地址分配给一组预留寄存器作为其高bit位，在M个预留寄存器中进行存储。下一次发生bit位溢出，再次分配另一组预留寄存器，对溢出数据进行存储，因而避免了回波信号丢失。
根据本发明的一个优选实施例，所述预留寄存器包括N组寄存器，其中N为预设值，每组寄存器用于一个发生溢出或将要发生溢出的存储单元。N的个数根据系统允许的最多回波脉冲个数确定，如系统最多统计计算3个回波脉冲信息，令N＝3。M根据存储数据最大值确定，比如原本最大需要16bit的寄存器，可设置32个8bit寄存器作为一组预留寄存器。
通过上述的方式，对于多次扫描获得的探测数据，将以第一时间精度，按照时间信息的权重，存储所探测数据中的强度信息，根据存储的数据，可以形成直方图，利用该直方图，计算在时间轴上的中心，就能够获得更准确的回波脉冲位置以及飞行时间。
因此，本发明还提供一种数据的处理方法，其中所述数据通过如上所述的存储方法100存储在存储器的存储单元中，所述处理方法包括：
读取与每个第一时间刻度对应的存储单元中存储的数值；
计算所述数值在时间轴上的重心。
在计算出所述数值在时间轴上的重心之后，可以将该重心对应的时间轴的坐标(例如细刻度的坐标)作为回波脉冲的飞行时间，用于计算目标物的距离。
作为另一个优选实施例，所述处理方法包括：
完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；获取回波脉冲的前沿时间。具体的，将对应回波脉冲前沿的数值与预设阈值相比较，将强度等于上述预设阈值的数值对应的时间信息作为前沿时间，用于计算目标物的距离。
作为一个具体实施方式，预设阈值为噪声阈值。
作为一个具体实施方式，预设阈值为噪声阈值和脉冲峰值的平均值。
本发明还提供一种可用于激光雷达的数据处理方法200，如图10所示，包括：
在步骤S201：接收回波的接收时刻以及强度信息。例如使用图5所示的接收单元22来接收激光雷达的回波，所述接收时刻为每个宏像素中的单光子雪崩二极管SPAD被触发的时刻，所述强度信息可通过该时刻被触发的单光子雪崩二极管的数目来表征。
在步骤S202：基于探测脉冲的发射时刻和所述接收时刻确定时间信息。
基于探测脉冲的发射时刻和回波的接收时刻，可以获得时间差，即该次回波的飞行时间，用作时间信息。
在步骤S203：以第一时间精度，按照所述时间信息的权重，存储所述强度信息；其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
如上文参考图6-图8描述的，以第一时间精度(相对更粗的精度，而非按照激光雷达的时间分辨率的精度或者说激光雷达系统可以达到的时间分辨率的精度)，按照所述时间信息的权重，存储所述强度信息，此处不再赘述。
根据本发明的一个优选实施例，激光雷达在对一个视场范围(例如三维环境中的一个部位)进行探测时，对该视场范围进行多次扫描，根据多次扫描的探测信息来获得该部位的距离信息。所述步骤S203包括：以第一时间精度，将所述多次扫描获得的强度信息叠加存储。
完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值，然后例如可以生成直方图，计算所述数值在时间轴上的重心，将所述重心对应的时间信息作为飞行时间，计算该飞行时间对应的距离。
作为另一个优选实施例，完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；获取回波脉冲的前沿时间。具体的，将对应回波脉冲的前沿的数值与预设阈值相比较，将强度等于预设阈值的数值对应的时间信息作为前沿时间。
作为一个具体实施方式，预设阈值为噪声阈值。
作为一个具体实施方式，预设阈值为噪声阈值和脉冲峰值的平均值。
本发明还提供一种激光雷达20，如图11所示。激光雷达20包括发射模块21、探测模块22、采样装置23以及处理装置24。其中发射模块21包括多个发射单元(例如多个激光器)，用于向三维环境中发射激光探测脉冲L，探测目标物。探测模块22包括多个探测单元，用于接收所述激光探测脉冲L在目标物上反射后的回波L'，并将所述回波转换为电信号。所述探测模块22例如可采用图5所示的探测模块22，包括多个由单光子雪崩二极管SPAD构成的探测单元。采样装置将所述电信号转换为数字信号，和/或可以获得回波的到达时间。根据本发明的一个优选实施例，采样装置可包括模数转换器ADC和时间数字转换器TDC。处理装置24与所述采样装置23耦接，也可以同时与所述发射单元21耦接，配置成根据所述数字信号确定探测数据，所述探测数据包括时间信息和与所述时间信息对应的强度信息，并以第一时间精度，按照所述时间信息的权重，存储所述强度信息；其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；所述权重与所述时间信息和至少一个第一时间刻 度的时间间隔相关联。
根据本发明的一个实施例，所述激光雷达配置成对一个视场范围进行多次扫描，其中所述处理装置配置成以第一时间精度，将所述多次扫描获得的强度信息叠加存储。
根据本发明的一个实施例，所述处理装置进一步配置成：完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；计算所述数值在时间轴上的重心；将所述重心对应的时间信息作为飞行时间。
作为本发明的另一个实施例，所述处理装置进一步配置成：完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；获取回波脉冲的前沿时间。具体的，将对应回波脉冲的前沿的数值与预设阈值相比较，将强度等于预设阈值的数值对应的时间信息作为前沿时间。
作为一个具体实施方式，预设阈值为噪声阈值。
作为一个具体实施方式，预设阈值为噪声阈值和脉冲峰值的平均值。
根据本发明的一个实施例，所述多个发射单元对应不同的视场范围，即发射探测光束至不同的视场范围，多个所述视场范围组成所述激光雷达的探测范围。
根据本发明的一个实施例，每个所述发射单元依次发出探测光束至相应的视场范围，当其中一个发射单元发出探测光束后，与该发射单元的视场范围相对应的的至少一个探测单元被激活开始探测。
本发明还涉及一种计算机可读存储介质,包括存储于其上的计算机可执行指令，所述可执行指令在被处理器执行时实施如上所述的存储方法100。
最后应说明的是：以上所述仅为本发明的优选实施例而已，并不用于限制本发明，尽管参照前述实施例对本发明进行了详细的说明，对于本领域的技术人员来说，其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (23)

  1. 一种雷达的探测数据的存储方法，包括：
    S101：接收探测数据，所述探测数据包括时间信息和与所述时间信息对应的强度信息；和
    S102：以第一时间精度，按照所述时间信息的权重，存储所述强度信息；
    其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；
    所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
  2. 如权利要求1所述的存储方法，其中所述权重包括第一权重和第二权重，所述第一权重与所述时间信息和其中一个相邻的第一时间刻度之间的时间间隔相关联，所述第二权重与所述时间信息与另一个相邻的第一时间刻度之间的时间间隔相关联，所述步骤S102包括：以第一时间精度，分别按照所述第一权重和第二权重，存储所述强度信息。
  3. 如权利要求2所述的存储方法，其中，所述第一权重为n-x，所述第二权重为x，其中x表示所述时间信息与相邻的第一时间刻度的时间间隔为x倍的雷达探测数据时间分辨率。
  4. 如权利要求3所述的存储方法，其中所述第一权重为所述时间信息对应其左侧相邻的第一时间刻度的权重，所述第二权重为所述时间信息对应其右侧相邻的第一时间刻度的权重，其中x表示所述时间信息与其左侧相邻的第一时间刻度的时间间隔为x倍的雷达探测数据时间分辨率。
  5. 如权利要求2所述的存储方法，所述第一权重为1-(x/n)，所述第二预设权重为x/n，其中x表示所述时间信息与其左侧相邻的第一时间刻度的时间间隔为x倍的雷达探测数据时间分辨率。
  6. 如权利要求1所述的存储方法，其中n＝2 m，m为正整数。
  7. 如权利要求1-6中任一项所述的存储方法，其中所述强度信息包括探测单元的触发数量。
  8. 如权利要求1-6中任一项所述的存储方法，其中存储器中具有与每个第一时间刻度对应的存储单元，所述步骤S102包括：按照第一权重和第二权重，将所述强度信息存储在与所述时间信息相邻的两个第一时间刻度相对应的两个存储单元中。
  9. 如权利要求8所述的存储方法，其中所述步骤S102还包括：当向其中一个存储单元按照所述权重存入所述强度信息时，
    读取所述存储单元中存储的数值；
    将所述强度信息根据所述权重计算的数值与所读取的数值累加；和
    将累加的结果写入所述存储单元中。
  10. 如权利要求8所述的存储方法，还包括：当判断其中一个存储单元发生溢出或者将要发生溢出时，从预留寄存器中为所述存储单元分配另外的存储地址。
  11. 如权利要求10所述的存储方法，其中所述预留寄存器包括N组寄存器，其中N为预设值，每组寄存器用于一个发生溢出或将要发生溢出的存储单元。
  12. 一种可用于激光雷达的数据处理方法，包括：
    S201：获取光信号的接收时刻以及强度信息；
    S202：基于探测脉冲的发射时刻和所述接收时刻确定时间信息；
    S203：以第一时间精度，按照所述时间信息的权重，存储所述强度信息；
    其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；
    所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
  13. 如权利要求12所述的数据处理方法，其中所述激光雷达对一个视场范围进行多次扫描，其中所述步骤S203包括：以第一时间精度，将所述多次扫描获得的强度信息叠加存储。
  14. 如权利要求13所述的数据处理方法，还包括：
    完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；
    计算所述数值在时间轴上的重心；
    将所述重心作为飞行时间。
  15. 如权利要求13所述的数据处理方法，还包括：
    完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值，获取回波脉冲的前沿时间；
    其中，所述前沿时间为：
    比较对应所述回波脉冲前沿的所述数值与预设阈值，将强度等于预设阈值的所述数值对应的时间信息作为所述前沿时间。
  16. 一种激光雷达，包括：
    发射模块，包括多个发射单元，用于发射激光探测脉冲；
    探测模块，包括多个探测单元，用于接收所述激光探测脉冲在目标物上反射后的回波，并将所述回波转换为电信号；
    采样装置；将所述电信号转换为数字信号；
    处理装置，与所述采样装置耦接，配置成根据所述数字信号确定探测数据，所述探测数据包括时间信息和与所述时间信息对应的强度信息，并以第一时间精度，按照所述时间信息的权重，存储所述强度信息；
    其中，所述第一时间精度为任意两个相邻第一时间刻度之间的时间间隔，且为所述雷达的探测数据的时间分辨率的n倍,其中n>1；所述权重与所述时间信息和至少一个第一时间刻度的时间间隔相关联。
  17. 如权利要求16所述的激光雷达，其中所述激光雷达配置成对一个视场范围进行多次扫描，其中所述处理装置配置成以第一时间精度，将所述多次扫描获得的强度信息叠加存储。
  18. 如权利要求17所述的激光雷达，其中所述处理装置进一步配置成：
    完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值；
    计算所述数值在时间轴上的重心；
    将所述重心作为飞行时间。
  19. 如权利要求17所述的激光雷达，其中所述处理装置进一步配置成：
    完成所述多次扫描后，读取与每个第一时间刻度对应的存储单元中存储的数值，获取回波脉冲的前沿时间；
    其中，所述前沿时间为：
    比较对应所述回波脉冲前沿的所述数值与预设阈值，将强度等于预设阈值的所述数值对应的时间信息作为所述前沿时间。
  20. 如权利要求16-19中任一项所述的激光雷达，其中所述多个发射单元发射探测光束至不同的视场范围，多个所述视场范围组成所述激光雷达的探测范围。
  21. 如权利要求16-19中任一项所述的激光雷达，其中所述探测单元包括基于盖革模式的探测单元，所述采样装置包括时间数字转换器。
  22. 如权利要求16-19中任一项所述的激光雷达，其中每个所述发射单元依次发出探测光束至相应的视场范围，当其中一个发射单元发出探测光束后，与该发射单元的视场范围相对应的的至少一个探测单元被激活开始探测。
  23. 一种计算机可读存储介质,包括存储于其上的计算机可执行指令，所述可执行指令在被处理器执行时实施如权利要求1-11中任一项所述的存储方法。
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