WO2021077253A1 - 测量方法、装置、可移动平台和计算机可读介质 - Google Patents

测量方法、装置、可移动平台和计算机可读介质 Download PDF

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Publication number
WO2021077253A1
WO2021077253A1 PCT/CN2019/112211 CN2019112211W WO2021077253A1 WO 2021077253 A1 WO2021077253 A1 WO 2021077253A1 CN 2019112211 W CN2019112211 W CN 2019112211W WO 2021077253 A1 WO2021077253 A1 WO 2021077253A1
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pulse signal
reflected pulse
time
sampling
reflected
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PCT/CN2019/112211
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English (en)
French (fr)
Inventor
许友
吴特思
陈涵
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深圳市大疆创新科技有限公司
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Priority to CN201980030612.6A priority Critical patent/CN114270219A/zh
Priority to PCT/CN2019/112211 priority patent/WO2021077253A1/zh
Publication of WO2021077253A1 publication Critical patent/WO2021077253A1/zh

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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
    • 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
    • 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
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/285—Receivers
    • G01S7/292—Extracting wanted echo-signals

Definitions

  • the present invention generally relates to the field of laser detection technology, and more specifically relates to a measurement method, a device, a movable platform, and a computer-readable medium.
  • the three-dimensional point cloud detection system including lidar emits pulsed laser light from the transmitting end, which is reflected by the object, and the receiving end of the detection system receives the reflected pulse to calculate the time of flight (TOF) distance.
  • TOF time of flight
  • the pulse time identification technology used to calculate the TOF distance has the problem of low accuracy.
  • embodiments of the present invention provide a measurement solution, which can effectively overcome TOF measurement errors introduced due to pulse distortion and distortion, and improve TOF measurement accuracy.
  • the measurement scheme proposed by the present invention will be briefly described below, and more details will be described later in the specific implementation with reference to the accompanying drawings.
  • a measurement method includes: transmitting a light pulse signal to an object to be measured; receiving a reflected pulse signal corresponding to the light pulse signal; sampling the reflected pulse signal to obtain a sampling result Calculate the time measurement value and time correction value corresponding to the reflected pulse signal based on the sampling result, and calculate the time between the optical pulse signal and the reflected pulse signal based on the time measurement value and the time correction value interval.
  • a measurement method includes: transmitting a light pulse signal to an object to be measured; receiving a plurality of reflected pulse signals corresponding to the light pulse signal; Each of the samples is sampled to obtain a sampling result; for each of the reflected pulse signals, it is determined whether the reflected pulse signal is affected by adjacent reflected pulse signals, and if it is determined to be affected, it is based on the sampling result of the reflected pulse signal Part of the data in calculates the time interval between the optical pulse signal and the reflected pulse signal.
  • a measuring device comprising: a transmitter, a receiver, a sampling device, and a processor, wherein: the transmitter is used to transmit a light pulse signal to the measured object; the receiver The device is used to receive the reflected pulse signal corresponding to the optical pulse signal; the sampling device is used to sample the reflected pulse signal to obtain a sampling result; the processor is used to calculate the reflected pulse signal corresponding to the sampling result A time measurement value and a time correction value, and a time interval between the optical pulse signal and the reflected pulse signal is calculated based on the time measurement value and the time correction value.
  • a measuring device comprising: a transmitter, a receiver, a sampling device, and a processor, wherein: the transmitter is used to transmit a light pulse signal to the measured object; the receiver The device is used to receive multiple reflected pulse signals corresponding to the optical pulse signal; the sampling device is used to sample each of the multiple reflected pulse signals to obtain a sampling result; the processor is used to The reflected pulse signal determines whether the reflected pulse signal is affected by the adjacent reflected pulse signal, and if it is determined to be affected, the optical pulse signal and the reflected pulse are calculated based on part of the data in the sampling result of the reflected pulse signal The time interval between signals.
  • a movable platform comprising: a fuselage; a power system installed on the fuselage for providing flight power; the above-mentioned measuring device installed on the On the fuselage, it is used to perceive the environment where the movable platform is located and generate point cloud information.
  • a computer-readable medium is provided, and a computer program is stored on the computer-readable medium, and the computer program executes the above-mentioned measurement method when running.
  • the measurement method, device, movable platform, and computer-readable medium consider the pulse distortion problem when calculating the time interval between the optical pulse signal and its corresponding reflected pulse signal, and not only calculate the corresponding reflected pulse signal
  • the corresponding time correction value is also calculated, and the final result of the time interval is calculated based on the time measurement value and the time correction value, which can effectively overcome the measurement error introduced by pulse distortion and distortion and improve the measurement accuracy.
  • Figure 1 shows a schematic diagram of the TOF measurement principle based on TDC sampling.
  • Figure 2 shows a schematic diagram of the waveform of the sampled pulse with distortion.
  • Fig. 3 shows an example diagram of an ideal Gaussian pulse time discrimination model.
  • Fig. 4 shows a schematic flowchart of a measurement method according to an embodiment of the present invention.
  • Fig. 5 shows an example diagram of a time discrimination model for non-ideal pulses.
  • Figure 6 shows a schematic diagram of the fusion and influence of multiple pulses.
  • Fig. 7 shows a schematic flowchart of a measurement method according to an embodiment of the present invention.
  • Figure 8 shows a schematic diagram of the waveform of the pulse to be measured affected by the previous pulse.
  • Fig. 9 shows a schematic block diagram of a measuring device according to an embodiment of the present invention.
  • Fig. 10 shows a schematic block diagram of a measuring device according to an embodiment of the present invention.
  • Fig. 11 shows a schematic block diagram of a movable platform according to an embodiment of the present invention.
  • the TOF distance is calculated from the receiving end of the detection system until the reflected pulse is received by the receiving end of the detection system by emitting pulsed laser light from the transmitting end.
  • the embodiment of the present invention adopts a time-to-digital converter (TDC) to sample the reflected pulse to perform TOF distance calculation based on the sampled reflected pulse.
  • TDC time-to-digital converter
  • FIG. 1 shows a schematic diagram of the TOF measurement principle based on TDC sampling.
  • the transmitter emits a light pulse signal to the measured object
  • the receiver receives the reflected pulse signal from the measured object
  • the TDC samples the reflected pulse signal.
  • n is a natural number
  • the sampling point can be recorded as 0.
  • the pulse signal is sampled by multiple TDCs with different voltage thresholds.
  • the points on the rising and falling edges of each TDC sample correspond to the same voltage threshold and correspond to different time values, for example, as shown in Figure 2.
  • the t01 and t11 are the sampling results of one TDC (denoted as TDC1)
  • t02 and t12 are the sampling results of another TDC (denoted as TDC2). Based on the above sampling results, the TOF distance information and pulse shape information of the measured pulse can be obtained.
  • the existing pulse timing identification methods based on TDC sampling mostly ignore the distortion problem caused by the photoelectric conversion circuit, that is, the pulse distortion problem (as shown in Figure 2), but the electrical pulse signal that is still being sampled.
  • the TOF distance of the pulse is marked as t tof .
  • the TDC will produce a relatively fixed offset when the pulse is sampled. , Recorded here as t offset .
  • the above model will introduce a certain measurement error, which will cause the measured value of the TOF distance to deviate from the true value, resulting in the degradation of the measurement system performance.
  • the present invention provides a measurement method.
  • the measurement method according to an embodiment of the present invention will be described in detail below with reference to FIG. 4.
  • FIG. 4 shows a schematic flowchart of a measurement method 400 according to an embodiment of the present invention. As shown in FIG. 4, the measurement method 400 may include the following steps:
  • step S410 a light pulse signal is emitted to the object to be measured.
  • step S420 a reflected pulse signal corresponding to the optical pulse signal is received.
  • step S430 the reflected pulse signal is sampled to obtain a sampling result.
  • step S440 the time measurement value and the time correction value corresponding to the reflected pulse signal are calculated based on the sampling result, and the difference between the optical pulse signal and the reflected pulse signal is calculated based on the time measurement value and the time correction value. The time interval between.
  • the distortion and distortion of the sampled pulse signal are considered. As shown in FIG. 5, in the process of converting the optical pulse signal into an electrical pulse signal, it is inevitable that the amplifier circuit is adjusted. There are distortion phenomena, such as saturation, overshoot, etc., which directly cause the distortion of the rising and falling edges of the pulse signal. Therefore, in the measurement method 400 according to the embodiment of the present invention, not only the time measurement value corresponding to the reflected pulse signal is calculated according to the sampling result of the reflected pulse signal, but also the corresponding time correction value is calculated based on the time measurement value and the time correction value. The final result of the time interval is calculated. Therefore, the measurement error introduced by the pulse distortion and distortion can be effectively overcome, and the measurement accuracy can be improved.
  • the sampling result obtained in step S430 may include multiple sampling points, each sampling point corresponding to a voltage value and a time value, and the set of voltage values corresponding to the multiple sampling points is defined as Voltage set, the set of time values corresponding to the multiple sampling points is defined as a time set, and calculating the time correction value based on the sampling result may include: calculating the time correction value according to a preset correction model, and the prediction Let the modified model be a function of the voltage set and the time set.
  • the following uses TDC to sample the reflected pulse signal as an example to describe.
  • the multi-channel TDC samples the reflected pulse signal in multiple channels, and each channel of sampling obtains a rising edge sampling point and a falling edge sampling point.
  • the rising edge sampling point and The falling edge sampling points have the same voltage value and different time values. Assuming that the voltage thresholds of each sampling of n channels of TDC are TDC 1 , TDC 2 , ...
  • the time measurement value calculated in step S430 may be expressed as g( ⁇ )
  • the time correction value calculated in step S430 may be expressed as f( ⁇ , ⁇ ).
  • the time interval t tof between the optical pulse signal and the reflected pulse signal calculated based on the time measurement value and the time correction value can be:
  • the time measurement value g( ⁇ ) can be equal to the arithmetic mean value of the time set T, that is
  • the time measurement value g(T) may also be equal to the weighted average of the time set T. In other examples, the time measurement value g(T) may also be equal to the average value of the subset of the time set T or one of the values in the time set T.
  • the time correction value f( ⁇ , ⁇ ) is a preset correction model for correcting the error of the time measurement value g( ⁇ ).
  • the input ( ⁇ , ⁇ ) represents all the voltage threshold information and time information measured by the pulse. This is only exemplary. In other examples, other characterization indicators can be flexibly selected to obtain the modified model.
  • the characterization index may also be pulse width, pulse width sum, slope, pulse area, pulse amplitude, and the like.
  • the function form f of the preset correction model can be flexibly selected, for example, it can be a Gaussian function, a polynomial function, a neural network, etc., or a combination of multi-function models.
  • the parameters of the above-mentioned preset correction model can be obtained by the following method: obtaining a plurality of calibration reflected pulse signals, and the true time value corresponding to each calibration reflected pulse signal is known; Each calibration reflected pulse signal is sampled to obtain a sampling result; the time measurement value corresponding to each calibration reflected pulse signal is calculated based on the sampling result of each calibration reflected pulse signal; based on each calibration reflected pulse signal The time real value of and the time measurement value of each calibrated reflected pulse signal are calculated to calculate the parameters of the preset correction model.
  • experimental modeling can be used to obtain a large amount of pulse sampling point calibration data at a known distance (TOF true value) to obtain the model parameters of the preset correction model ( ⁇ , ⁇ ).
  • TOF true value of the calibration data can be obtained by high-precision reference measuring instruments, such as higher-precision laser scanners, total stations, laser trackers, etc.
  • the implementation process of the calibration method mainly includes the following three steps:
  • step 1 obtain a large amount of ground truth calibration point data.
  • the method of obtaining calibration point data may include, but is not limited to, changing the placement distance, reflectivity, size, shape and other characteristics of the calibration object. For example, the measurement system is fixed, calibration boards are placed in different positions in the calibration scene, and the pulse signals on different calibration boards are scanned and collected.
  • step two a TOF correction model is established.
  • the correction model is to input the pulse signal information and calculate the TOF time correction value through the model.
  • the TOF correction model can be obtained as:
  • step three solve the above equations to obtain the TOF modified model.
  • the number of calibration points n is much larger than the number of parameters of the TOF correction model f( ⁇ , ⁇ ). Therefore, through the optimization method, the optimal value of the error model parameters can be obtained.
  • the measurement method 400 considers the pulse distortion problem when calculating the time interval between the optical pulse signal and its corresponding reflected pulse signal, and not only calculates the time measurement value corresponding to the reflected pulse signal, but also Calculate the corresponding time correction value, and calculate the final result of the time interval based on the time measurement value and the time correction value, which can effectively overcome the measurement error introduced due to pulse distortion and distortion, and improve the measurement accuracy.
  • TDC to sample the reflected pulse signal
  • ADC analog to digital converter
  • TOF laser ranging may have multiple pulse echoes, such as T0 of the coaxial optical path as shown in Figure 6, T1, T2, etc. of multiple products under test.
  • T0 of the coaxial optical path as shown in Figure 6, T1, T2, etc. of multiple products under test.
  • the mutual fusion and influence between multiple pulse echoes will also affect the TOF measurement results.
  • a measurement method 700 is provided.
  • the measurement method according to another embodiment of the present invention will be described in detail below with reference to FIG. 7.
  • FIG. 7 shows a schematic flowchart of a measurement method 700 according to another embodiment of the present invention. As shown in FIG. 7, the measurement method 700 may include the following steps:
  • step S710 a light pulse signal is emitted to the object to be measured.
  • step S720 receiving multiple reflected pulse signals corresponding to the optical pulse signal
  • step S730 each of the multiple reflected pulse signals is sampled to obtain a sampling result.
  • step S740 for each of the reflected pulse signals, it is determined whether the reflected pulse signal is affected by the adjacent reflected pulse signal, and if it is determined to be affected, the reflected pulse signal is calculated based on part of the data in the sampling result of the reflected pulse signal. The time interval between the optical pulse signal and the reflected pulse signal.
  • the measurement method 700 when a multi-pulse signal is received, whether a reflected pulse signal is affected by adjacent reflected pulse signals is considered. If it is determined that the reflected pulse signal is affected by adjacent reflected pulses The influence of the pulse signal means that the results of some sampling points of the reflected pulse signal may be inaccurate. Therefore, the results of this part of the sampling points can be excluded, and the time is based only on the sampling results of other unaffected parts. The calculation of the interval can improve the accuracy of the measurement.
  • each channel of sampling obtains a rising edge sampling point and a falling edge sampling point, the rising edge sampling point and the falling edge sampling point have the same voltage value and different time values .
  • the adjacent reflected pulse signal includes the previous reflected pulse signal of the reflected pulse signal, and if it is determined that it is affected by the previous reflected pulse signal, it is based on the falling edge sampling obtained by the multiple sampling Point to calculate the time interval between the optical pulse signal and the reflected pulse signal.
  • the adjacent reflected pulse signal includes the next reflected pulse signal of the reflected pulse signal, and if it is determined to be affected by the latter reflected pulse signal, it is based on the rising edge obtained by the multi-channel sampling. The sampling point calculates the time interval between the optical pulse signal and the reflected pulse signal.
  • the following description takes three pulse signals received as an example.
  • the three pulses are respectively marked as the first pulse signal, the second pulse signal, and the third pulse signal.
  • the first pulse signal can be, for example, an optical device echo.
  • the second pulse signal and the third pulse signal can be echoes of the measured object.
  • the following first describes the situation affected by the previous reflected pulse signal. Assume that the reflected pulse signal to be sampled is the second pulse signal (corresponding to T1 in Figure 8). Under normal circumstances, the waveform of the second pulse signal should be as shown in echo 1 in Figure 8, but it is affected by the first Due to the influence of the pulse signal (corresponding to T0 in FIG. 8, the waveform is echo 0), the waveform of the second pulse signal is actually shown by echo 1'in FIG.
  • the difference between the optical pulse signal and the reflected pulse signal can be calculated based on all or part of the data in the sampling result of the reflected pulse signal. time interval.
  • the measurement method considers whether a reflected pulse signal is affected by the adjacent reflected pulse signal when a multi-pulse signal is received. If it is determined that the reflected pulse signal is affected For the influence of adjacent reflected pulse signals, the time interval calculation is only based on the sampling results of other unaffected parts, which can effectively improve the accuracy of the measurement.
  • the measurement methods according to different embodiments of the present invention are described above with reference to FIGS. 4 and 7 respectively. It should be understood that the two measurement methods have different focus on the problems they solve, and the former mainly solves the measurement problem when the received reflected pulse signal is distorted. The latter mainly solves the measurement problem when the received multiple reflected pulse signals affect each other. It should be understood that these two measurement methods can be performed independently or combined with each other.
  • the receiving the reflected pulse signal corresponding to the optical pulse signal in step S420 in the measurement method 400 may include: receiving the optical pulse Signal corresponding to multiple reflected pulse signals, and the calculation of the time measurement value and time correction value corresponding to the reflected pulse signal based on the sampling result in step S440 further includes: for each of the multiple reflected pulse signals The reflected pulse signal determines whether the reflected pulse signal is affected by the adjacent reflected pulse signal; if it is determined that the reflected pulse signal is affected by the adjacent reflected pulse signal, the time corresponding to the reflected pulse signal is calculated based on part of the data in the sampling result Measured value and time correction value.
  • the sampling of the reflected pulse signal in step S430 in the measurement method 400 may include: multi-channel sampling of the reflected pulse signal, and each sampling method obtains a rising edge sampling point and a falling edge sampling point , The rising edge sampling point and the falling edge sampling point have the same voltage value and different time values.
  • calculating the time measurement value and the time correction value corresponding to the reflected pulse signal based on the sampling result may further include: when it is determined that the reflected pulse signal is affected by the previous reflected pulse signal, based on The time measurement value and the time correction value corresponding to the reflected pulse signal are calculated at the falling edge sampling points obtained by the multiple sampling.
  • step S440 of the measurement method 400 calculating the time measurement value and the time correction value corresponding to the reflected pulse signal based on the sampling result may further include: when it is determined that the reflected pulse signal is affected by the subsequent reflected pulse signal, Calculate the time measurement value and the time correction value corresponding to the reflected pulse signal based on the rising edge sampling points obtained by the multi-path sampling.
  • calculating the time measurement value and the time correction value corresponding to the reflected pulse signal based on the sampling result may further include: if it is determined that the reflected pulse signal is not affected by the adjacent reflected pulse signal, then based on the sampling All or part of the data in the result calculates the time measurement value and the time correction value corresponding to the reflected pulse signal.
  • the calculation method of the above-mentioned time measurement value and time correction value is similar to that described in the foregoing, for the sake of brevity, it will not be repeated here.
  • the calculation of the time interval between the optical pulse signal and the reflected pulse signal in step S740 in the measurement method 700 may be The method includes: calculating a time measurement value and a time correction value corresponding to the reflected pulse signal, and calculating a time interval between the optical pulse signal and the reflected pulse signal based on the time measurement value and the time correction value.
  • the sampling result obtained in step S730 in the measurement method 700 may include multiple sampling points, each sampling point corresponding to a voltage value and a time value, and the set of voltage values corresponding to the multiple sampling points is defined as A voltage set, the set of time values corresponding to the multiple sampling points is defined as a time set; and the calculating the time correction value may include: calculating the time correction value according to a preset correction model, the preset correction model Is a function of the voltage set and the time set.
  • the functional form of the preset correction model includes at least one of the following: a Gaussian function, a polynomial function, and a neural network.
  • the parameters of the preset correction model are obtained in the following manner: obtaining a plurality of calibration reflected pulse signals, and the true time value corresponding to each calibration reflected pulse signal is known; and for each calibration reflected pulse signal; The reflected pulse signal is sampled to obtain the sampling result; the time measurement value corresponding to each calibrated reflected pulse signal is calculated based on the sampling result of each calibrated reflected pulse signal; the true time value of each calibrated reflected pulse signal is calculated based on the sum The time measurement value of each calibrated reflected pulse signal is calculated to calculate the parameters of the preset correction model.
  • the calculating the time measurement value corresponding to the reflected pulse signal includes: calculating the average value of the time set to obtain the time measurement value; calculating the average value of any subset of the time set, To obtain the time measurement value; select one of the values from the time set as the time measurement value.
  • the calculation method of the above-mentioned time measurement value and time correction value is similar to that described in the foregoing, for the sake of brevity, it will not be repeated here.
  • the measurement method according to the embodiment of the present invention is exemplarily described above.
  • the measurement devices 900 and 1000 provided according to another aspect of the present invention will be described below with reference to FIGS. 9 to 10.
  • the measurement devices 900 and 1000 according to the embodiment of the present invention can be used to implement the measurement methods 400 and 700 according to the embodiment of the present invention described above, respectively, and both can be used to implement the measurement method according to the embodiment of the present invention described above.
  • a combination of 400 and 700 For brevity, only the main structures and functions of the measuring devices 900 and 1000 are described below, and some specific details that have been described above are omitted.
  • the measurement device 900 may include a transmitter 910, a receiver 920, a sampling device 930, and a processor 940, where the transmitter 910 is used to transmit optical pulse signals to the object to be measured.
  • the receiver 920 is used to receive the reflected pulse signal corresponding to the optical pulse signal.
  • the sampling device 930 is configured to sample the reflected pulse signal to obtain a sampling result.
  • the processor 940 is configured to calculate a time measurement value and a time correction value corresponding to the reflected pulse signal based on the sampling result, and calculate the optical pulse signal and the reflected pulse signal based on the time measurement value and the time correction value The time interval between.
  • the measurement device 1000 may include a transmitter 1010, a receiver 1020, a sampling device 1030, and a processor 1040, where the transmitter 1010 is used to transmit an optical pulse signal to the object to be measured.
  • the receiver 1020 is configured to receive multiple reflected pulse signals corresponding to the optical pulse signals.
  • the sampling device 1030 is configured to sample each of the multiple reflected pulse signals to obtain a sampling result.
  • the processor 1040 is configured to determine, for each reflected pulse signal, whether the reflected pulse signal is affected by the adjacent reflected pulse signal, and if it is determined to be affected, calculate based on part of the data in the sampling result of the reflected pulse signal The time interval between the optical pulse signal and the reflected pulse signal.
  • a movable platform is also provided.
  • the movable platform 1100 may include a body 1110, a power system 1120, and a measuring device 1130.
  • the power system 1120 can be installed on the fuselage 1110 to provide flight power.
  • the measuring device 1130 can be installed on the fuselage 1110 to sense the environment where the movable platform 1100 is located and generate point cloud information.
  • the measuring device 1130 may be the measuring device 900 or the measuring device 1000 described above.
  • the movable platform 1100 may be a drone.
  • a computer-readable medium having a computer program stored on the computer-readable medium, and the computer program executes the measurement method according to the embodiment of the present invention when the computer program is running.
  • the computer-readable medium may include, for example, a memory card of a smart phone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disk only Read memory (CD-ROM), USB memory, or any combination of the above storage media.
  • the computer-readable storage medium may be any combination of one or more computer-readable storage media.
  • the measurement method, device, movable platform, and computer readable medium consider the pulse distortion problem when calculating the time interval between the optical pulse signal and its corresponding reflected pulse signal, not only calculating The time measurement value corresponding to the reflected pulse signal is also calculated, and the corresponding time correction value is calculated, and the final result of the time interval is calculated based on the time measurement value and the time correction value, which can effectively overcome the measurement error introduced by pulse distortion and distortion, and improve the measurement accuracy degree.
  • the measurement method, device, movable platform, and computer readable medium take into consideration the question of whether a reflected pulse signal is affected by adjacent reflected pulse signals when a multi-pulse signal is received, and if it is determined If the reflected pulse signal is affected by the adjacent reflected pulse signal, the time interval calculation is only based on the sampling results of other unaffected parts, which can effectively improve the accuracy of the measurement.
  • the disclosed device and method may be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components may be combined or It can be integrated into another device, or some features can be ignored or not implemented.
  • the various component embodiments of the present invention may be implemented by hardware, or by software modules running on one or more processors, or by a combination of them.
  • a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some modules according to the embodiments of the present invention.
  • DSP digital signal processor
  • the present invention can also be implemented as a device program (for example, a computer program and a computer program product) for executing part or all of the methods described herein.
  • Such a program for implementing the present invention may be stored on a computer-readable storage medium, or may have the form of one or more signals.
  • Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

Abstract

一种测量方法、装置、可移动平台和计算机可读介质,所述方法包括：向被测物发射光脉冲信号（S410）；接收所述光脉冲信号对应的反射脉冲信号（S420）；对所述反射脉冲信号进行采样得到采样结果（S430）；基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值,基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔（S440）。根据该测量方法、装置、可移动平台和计算机可读介质能够有效克服由于脉冲失真、畸变引进的测量误差，提高测量准确度。

Description

测量方法、装置、可移动平台和计算机可读介质
说明书
技术领域
本发明总体上涉及激光探测技术领域，更具体地涉及一种测量方法、装置、可移动平台和计算机可读介质。
背景技术
激光雷达在内的三维点云探测系统由发射端发射出脉冲激光，经物体反射，探测系统的接收端到接收到反射脉冲，从而计算飞行时间(Time of Flight，TOF)距离。目前，用于计算TOF距离的脉冲时刻鉴别技术存在准确度不高的问题。
发明内容
为了解决上述问题中的至少一个，本发明实施例提供一种测量方案，其能够有效克服由于脉冲失真、畸变引进的TOF测量误差，提高TOF测量准确度。下面简要描述本发明提出的测量方案，更多细节将在后续结合附图在具体实施方式中加以描述。
根据本发明一方面，提供了一种测量方法，所述方法包括：向被测物发射光脉冲信号；接收所述光脉冲信号对应的反射脉冲信号；对所述反射脉冲信号进行采样得到采样结果；基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值，基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
根据本发明另一方面，提供了一种测量方法，所述方法包括：向被测物发射光脉冲信号；接收所述光脉冲信号对应的多个反射脉冲信号；对所述多个反射脉冲信号中的每一个进行采样得到采样结果；对于每个所述反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响，如果确定受到影响，则基于所述反射脉冲信号的采样结果中的部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
根据本发明再一方面，提供了一种测量装置，所述装置包括：发射器、接收器、采样装置和处理器，其中：所述发射器用于向被测物发射光脉冲信号；所述接收器用于接收所述光脉冲信号对应的反射脉冲信号；所述采样装置用于对所述反射脉冲信号进行采样得到采样结果；所述处理器用于基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值，基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
根据本发明又一方面，提供了一种测量装置，所述装置包括：发射器、接收器、采样装置和处理器，其中：所述发射器用于向被测物发射光脉冲信号；所述接收器用于接收所述光脉冲信号对应的多个反射脉冲信号；所述采样装置用于对所述多个反射脉冲信号中的每一个进行采样得到采样结果；所述处理器用于对于每个所述反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响，如果确定受到影响，则基于所述反射脉冲信号的采样结果中的部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
根据本发明再一方面，提供了一种可移动平台，所述可移动平台包括：机身；动力系统，安装在所述机身上，用于提供飞行动力；上述测量装置，安装在所述机身上，用于感知所述可移动平台所处的环境并生成点云信息。
根据本发明又一方面，提供了一种计算机可读介质，所述计算机可读介质上存储有计算机程序，所述计算机程序在运行时执行上述测量方法。
根据本发明实施例的测量方法、装置、可移动平台和计算机可读介质在计算光脉冲信号和其对应的反射脉冲信号之间的时间间隔时考虑了脉冲畸变问题，不仅计算反射脉冲信号对应的时间测量值，还计算相应的时间修正值，并基于时间测量值和时间修正值计算得到时间间隔的最终结果，能够有效克服由于脉冲失真、畸变引进的测量误差，提高测量准确度。
附图说明
图1示出基于TDC采样的TOF测量原理的示意图。
图2示出被采样的脉冲存在畸变的波形示意图。
图3示出理想高斯脉冲时刻鉴别模型的示例图。
图4示出根据本发明实施例的测量方法的示意性流程图。
图5示出非理想脉冲的时刻鉴别模型的示例图。
图6示出多脉冲相互融合、影响的示意图。
图7示出根据本发明实施例的测量方法的示意性流程图。
图8示出被测脉冲受到前一脉冲影响的波形示意图。
图9示出根据本发明实施例的测量装置的示意性框图。
图10示出根据本发明实施例的测量装置的示意性框图。
图11示出根据本发明实施例的可移动平台的示意性框图。
具体实施方式
为了使得本发明的目的、技术方案和优点更为明显，下面将参照附图详细描述根据本发明的示例实施例。显然，所描述的实施例仅仅是本发明的一部分实施例，而不是本发明的全部实施例，应理解，本发明不受这里描述的示例实施例的限制。基于本发明中描述的本发明实施例，本领域技术人员在没有付出创造性劳动的情况下所得到的所有其它实施例都应落入本发明的保护范围之内。
在下文的描述中，给出了大量具体的细节以便提供对本发明更为彻底的理解。然而，对于本领域技术人员而言显而易见的是，本发明可以无需一个或多个这些细节而得以实施。在其他的例子中，为了避免与本发明发生混淆，对于本领域公知的一些技术特征未进行描述。
应当理解的是，本发明能够以不同形式实施，而不应当解释为局限于这里提出的实施例。相反地，提供这些实施例将使公开彻底和完全，并且将本发明的范围完全地传递给本领域技术人员。
在此使用的术语的目的仅在于描述具体实施例并且不作为本发明的限制。在此使用时，单数形式的“一”、“一个”和“所述/该”也意图包括复数形式，除非上下文清楚指出另外的方式。还应明白术语“组成”和/或“包括”，当在该说明书中使用时，确定所述特征、整数、步骤、操作、元件和/或部件的存在，但不排除一个或更多其它的特征、整数、步骤、操作、元件、部件和/或组的存在或添加。在此使用时，术语“和/或”包括相关所列项目的任何及所有组合。
为了彻底理解本发明，将在下列的描述中提出详细的步骤以及详细的结构，以便阐释本发明提出的技术方案。本发明的较佳实施例详细描述如下，然而除了这些详细描述外，本发明还可以具有其他实施方式。
在诸如激光雷达等激光测距技术领域，通过由发射端发射出脉冲激光，经物体反射，探测系统的接收端到接收到反射脉冲，从而计算TOF距离。其中，本发明实施例采用时间数字转换器(Time to Digital Converter,TDC)对反射脉冲进行采样来基于经采样的反射脉冲进行TOF距离计算。
图1示出了基于TDC采样的TOF测量原理的示意图。如图1所示，发射器向被测物发射光脉冲信号，接收器从被测物接收反射脉冲信号，TDC对反射脉冲信号进行采样。假定共有n路TDC(n为自然数)对一个脉冲信号进行采样，通常情况下每一路TDC可以采集到上升沿和下降沿两个采样点，获得的采样点可以记为t ij(i∈[0,1],j∈[1,n])，例如i＝0表示上升沿，i＝1表示下降沿，j表示某一路TDC的序号。特别地，若某一路TDC未采集到脉冲信息，则该采样点可以记为0。通过设置不同的电压阈值的多路TDC对脉冲信号进行采样，每一路TDC采样的上升沿和下降沿上的点对应于同一个电压阈值，且对应于不同的时间值，例如如图2所示的t01和t11是一路TDC(记为TDC1)采样的结果，t02和t12是另一路TDC(记为TDC2)采样的结果。基于上述采样的结果，可获得被测脉冲的TOF距离信息及脉冲形状信息。
然而，现有的基于TDC采样的脉冲时刻鉴别方法大多忽略了光电转换电路带来的失真问题，即忽略了脉冲畸变问题(如图2所示的)，而是仍被采样的电脉冲信号当作理想的高斯脉冲，如图3所示的，该脉冲的TOF距离记为t tof，由于光电信号的转换、传输都存在一定的延迟，所以TDC对脉冲进行采样时会产生相对固定的偏移，这里记录为t offset。针对不同的脉冲信号均有：
Figure PCTCN2019112211-appb-000001
由于忽略了脉冲失真的问题，在实际的运用过程中，上述模型会引入一定的测量误差，使得TOF距离的测量值偏离真值，导致测量系统性能下降。
为了解决上述问题，本发明提供了一种测量方法，下面参照图4来具体描述根据本发明实施例的测量方法。
图4示出了根据本发明实施例的测量方法400的示意性流程图。如图4所示，测量方法400可以包括如下步骤：
在步骤S410，向被测物发射光脉冲信号。
在步骤S420，接收所述光脉冲信号对应的反射脉冲信号。
在步骤S430，对所述反射脉冲信号进行采样得到采样结果。
在步骤S440，基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值，基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
在根据本发明实施例的测量方法400中，考虑了被采样脉冲信号的畸变失真问题，如图5所示的，在光脉冲信号转换为电脉冲信号的过程中，由于调理放大电路不可避免的存在失真的现象，例如饱和、过冲等，直接导致了该脉冲信号上升沿和下降沿的畸变。因此，在根据本发明实施例的测量方法400中，不仅根据对反射脉冲信号的采样结果计算反射脉冲信号对应的时间测量值，还计算相应的时间修正值，并基于时间测量值和时间修正值计算得到时间间隔的最终结果，因此，能够有效克服由于脉冲失真、畸变引进的测量误差，提高测量准确度。
在本发明的实施例中，步骤S430中得到的采样结果可以包括多个采样点，每个采样点对应于一个电压值和一个时间值，所述多个采样点对应的电压值的集合定义为电压集合，所述多个采样点对应的时间值的集合定义为时间集合，并且基于所述采样结果计算所述时间修正值可以包括：根据预设修正模型计算所述时间修正值，所述预设修正模型为所述电压集合和所述时间集合的函数。
下面以采用TDC对反射脉冲信号进行采样为例来描述，多路TDC对反射脉冲信号进行多路采样，每一路采样得到一个上升沿采样点和一个下降沿采样点，所述上升沿采样点和所述下降沿采样点具有相同的电压值和不同的时间值。假定n路TDC各路采样的电压阈值分别为TDC 1、TDC 2、……TDC n，那么所采样的采样点的电压集合为(TDC 1,TDC 2,……,TDC n)，假定将该电压集合记为Ψ，那么Ψ＝(TDC 1,TDC 2,......,TDC n)；假定 将n路TDC采样得到的上升沿和下降沿时间信息记为T，那么Τ＝(t 01,t 02,......,t 1(n-1),t 1n)。基于此，步骤S430中所计算的时间测量值可以表示为g(Τ)，步骤S430中所计算的时间修正值可以表示为f(Ψ,Τ)。基于时间测量值和时间修正值计算的光脉冲信号与反射脉冲信号之间的时间间隔t tof可以为：
t tof＝g(Τ)+f(Ψ,Τ)
在一个示例中，时间测量值g(Τ)可以等于时间集合T的算术平均值，即
Figure PCTCN2019112211-appb-000002
在另一个示例中，时间测量值g(Τ)还可以等于时间集合T的加权平均。在其他示例中，时间测量值g(Τ)还可以等于时间集合T的子集的平均值或者时间集合T中的其中一个值等。
在本发明的实施例中，时间修正值f(Ψ,Τ)为对时间测量值g(Τ)的误差进行修正的预设修正模型。在上述的示例中，输入的(Ψ,Τ)表征该脉冲测量到的所有电压阈值信息及时间信息。这仅是示例性的，在其他示例中，还可以灵活选择其他表征指标来得到修正模型。示例性地，表征指标还可以为脉宽、脉宽和、斜率、脉冲面积、脉冲幅值等。例如，取TDC第2级阈值脉宽作为表征量，记为Δ＝t 12-t 02，故而误差模型则为f(Δ)。在本发明的实施例中，预设修正模型的函数形式f可以灵活选择，例如可以为高斯函数、多项式函数、神经网络等，或者多函数模型的组合等。
在本发明的实施例中，上述预设修正模型的参数可以通过如下方式求得：获取多个标定反射脉冲信号，每个所述标定反射脉冲信号所对应的时间真实值是已知的；对所述每个标定反射脉冲信号进行采样得到采样结果；基于所述每个标定反射脉冲信号的采样结果计算所述每个标定反射脉冲信号对应的时间测量值；基于所述每个标定反射脉冲信号的时间真实值和所述每个标定反射脉冲信号的时间测量值计算所述预设修正模型的参数。
在该实施例中，可以通过实验建模，获得大量已知距离(TOF真值)下脉冲的采样点标定数据，以求得预设修正模型(Ψ,Τ)的模型参数。其中，标定数据的TOF真值可以通过高精度的基准测量仪器得到，例如更高精度 的激光扫描仪、全站仪、激光跟踪仪等。标定方法的实施流程主要包括以下三个步骤：
在步骤一，获取大量已知真值(ground truth)的标定点数据。在本发明的实施例中，为获得更丰富、完备的脉冲信号，获取标定点数据的方式可以包括但不限于改变标定物的放置距离、反射率、大小、形状等特征。例如，固定测量系统，在标定场景内不同位置放置标定板，扫描采集不同标定板上的脉冲信号。
在步骤二，建立TOF修正模型。修正模型即通过输入脉冲信号信息，通过该模型计算得到TOF时间修正值，根据前述的非理想脉冲时刻鉴别模型t tof＝g(Τ)+f(Ψ,Τ)，可得TOF修正模型为：
f(Ψ,Τ)＝t ground_truth-t tof
假设采集到n个标定点的数据，即可建立修正模型的方程组：
Figure PCTCN2019112211-appb-000003
在步骤三，求解上述方程组得到TOF修正模型。通常情况下，标定点数n远大于TOF修正模型f(Ψ,Τ)的参数个数。所以，通过最优化的方法，即可得到误差模型参数的最优值。
基于上面的描述，根据本发明实施例的测量方法400在计算光脉冲信号和其对应的反射脉冲信号之间的时间间隔时考虑了脉冲畸变问题，不仅计算反射脉冲信号对应的时间测量值，还计算相应的时间修正值，并基于时间测量值和时间修正值计算得到时间间隔的最终结果，能够有效克服由于脉冲失真、畸变引进的测量误差，提高测量准确度。
虽然在上述示例中以采用TDC对反射脉冲信号进行采样为例来描述，但这仅是示例性的，在其他示例中，还可以采用其他采样装置对反射脉冲信号进行采样。例如，可以采用模拟数字转换器(analog to digital converter，ADC)对反射脉冲信号进行采样。
如前所述，TOF激光测距可能存在多个脉冲回波，如图6中所示的同轴光路的T0，多个被测物体产品的T1，T2……等。多个脉冲回波之间的相互融合和影响也将影响TOF测量结果。
基于此，在本发明的另一个实施例中，提供了一种测量方法700。下面参照图7来具体描述根据本发明另一个实施例的测量方法。
图7示出了根据本发明另一个实施例的测量方法700的示意性流程图。如图7所示，测量方法700可以包括如下步骤：
在步骤S710，向被测物发射光脉冲信号。
在步骤S720，接收所述光脉冲信号对应的多个反射脉冲信号；
在步骤S730，对所述多个反射脉冲信号中的每一个进行采样得到采样结果。
在步骤S740，对于每个所述反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响，如果确定受到影响，则基于所述反射脉冲信号的采样结果中的部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
在根据本发明实施例的测量方法700中，考虑了接收到多脉冲信号的情况时一个反射脉冲信号是否受到相邻反射脉冲信号的影响的问题，如果确定了该反射脉冲信号受到了相邻反射脉冲信号的影响，则意味着该反射脉冲信号的部分采样点的结果可能是不准确的，因此，可以将该部分采样点的结果排除在外，而仅基于其他未受影响部分的采样结果进行时间间隔的计算，这样可以提高测量的准确度。
下面仍以采用TDC对反射脉冲信号进行采样为例来描述，但应理解，采用其他采样装置(诸如ADC)对反射脉冲信号进行采样也是可以的。基于n路TDC对反射脉冲信号的采样，每一路采样得到一个上升沿采样点和一个下降沿采样点，所述上升沿采样点和所述下降沿采样点具有相同的电压值和不同的时间值。
在一个示例中，所述相邻反射脉冲信号包括所述反射脉冲信号的前一个反射脉冲信号，如果确定受到所述前一个反射脉冲信号的影响，则基于所述多路采样得到的下降沿采样点计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。在另一个示例中，所述相邻反射脉冲信号包括所述反射脉冲信号的后一个反射脉冲信号，如果确定受到所述后一个反射脉冲信号的影响，则基于所述多路采样得到的上升沿采样点计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
为了描述简单，下面以接收到三个脉冲信号为例来描述，三个脉冲分别记为第一脉冲信号、第二脉冲信号和第三脉冲信号，其中第一脉冲信号例如可以为光学器件回波，第二脉冲信号和第三脉冲信号可以为被测物体回波。下面首先描述受到前一个反射脉冲信号影响的情况。假定当前要采样的反射脉冲信号为第二脉冲信号(对应于图8中的T1)，正常情况下第二脉冲信号的波形应该为图8中的回波1所示的，但因为受到第一脉冲信号(对应于图8中的T0，波形为回波0)的影响，第二脉冲信号的波形实际为图8中的回波1’所示的。由图8可知，当前要采样的反射脉冲信号受到了前一脉冲信号的影响，导致其上升沿部分的采样点数据结果不准确，因此可以采用其下降沿部分的采样点数据来计算光脉冲信号和反射脉冲信号之间的时间间隔。也就是说，相应的时刻鉴别模型输入变为Τ＝(t 11,t 12,......,t 1(n-1),t 1n)。现在描述受到后一个反射脉冲信号影响的情况，与前面描述类似的，假定当前要采样的反射脉冲信号为第二脉冲信号，其受到了后一脉冲信号即前述第三脉冲信号的影响时，会导致其下降沿部分的采样点数据结果不准确，因此可以采用其上升沿部分的采样点数据来计算光脉冲信号和反射脉冲信号之间的时间间隔。也就是说，相应的时刻鉴别模型输入变为Τ＝(t 01,t 02,......,t 0(n-1),t 0n)。
在其他实施例中，如果确定一个反射脉冲信号未受到相邻反射脉冲信号的影响，则可以基于该反射脉冲信号的采样结果中的全部数据或部分数据计算光脉冲信号和反射脉冲信号之间的时间间隔。仍以上述的第一脉冲信号、第二脉冲信号和第三脉冲信号为例，在该实施例中，第二脉冲信号未受到第一脉冲信号和第三脉冲信号的影响，其上升沿和下降沿信息均未受到影响，因此可以选择使用其双沿的任何信息。也就是说，相应的时刻鉴别模型输入变为Τ＝(t 01,t 02,......,t 1(n-1),t 1n)。
基于上面的描述，根据本发明另一个实施例的测量方法考虑了接收到多脉冲信号的情况时一个反射脉冲信号是否受到相邻反射脉冲信号的影响的问题，如果确定了该反射脉冲信号受到了相邻反射脉冲信号的影响，则仅基于其他未受影响部分的采样结果进行时间间隔的计算，能够有效提高测量的准确度。
以上分别结合图4和图7描述了根据本发明不同实施例的测量方法， 应理解，这两种测量方法各自解决的问题侧重点不同，前者主要解决接收到的反射脉冲信号畸变时的测量问题，后者主要解决接收到的多个反射脉冲信号彼此之间相互影响时的测量问题，应理解，这两种测量方法可以独自进行，也可以相互结合。
例如，如果将测量方法700的实施例结合到测量方法400的实施例中，则测量方法400中的步骤S420中所述接收所述光脉冲信号对应的反射脉冲信号可以包括：接收所述光脉冲信号对应的多个反射脉冲信号，并且步骤S440中所述基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值进一步包括：对于所述多个反射脉冲信号中的每个反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响；如果确定受到相邻反射脉冲信号的影响，则基于所述采样结果中的部分数据计算所述反射脉冲信号对应的时间测量值和时间修正值。
进一步地，测量方法400中的步骤S430中所述对所述反射脉冲信号进行采样可以包括：对所述反射脉冲信号进行多路采样，每一路采样得到一个上升沿采样点和一个下降沿采样点，所述上升沿采样点和所述下降沿采样点具有相同的电压值和不同的时间值。测量方法400中的步骤S440中基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值可以进一步包括：当确定所述反射脉冲信号受到前一个反射脉冲信号的影响时，基于所述多路采样得到的下降沿采样点计算所述反射脉冲信号对应的时间测量值和时间修正值。测量方法400中的步骤S440中基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值还可以进一步包括：当确定所述反射脉冲信号受到后一个反射脉冲信号的影响时，基于所述多路采样得到的上升沿采样点计算所述反射脉冲信号对应的时间测量值和时间修正值。测量方法400中的步骤S440中基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值还可以进一步包括：如果确定未受到相邻反射脉冲信号的影响，则基于所述采样结果中的全部数据或部分数据计算所述反射脉冲信号对应的时间测量值和时间修正值。其中，上述时间测量值和时间修正值的计算方法与前文中描述的类似，为了简洁，此处不再赘述。
再如，如果将测量方法400的实施例结合到测量方法700的实施例中， 则测量方法700中的步骤S740中所述计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔可以包括：计算所述反射脉冲信号对应的时间测量值和时间修正值，并基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
进一步地，测量方法700中的步骤S730中得到的采样结果可以包括多个采样点，每个采样点对应于一个电压值和一个时间值，所述多个采样点对应的电压值的集合定义为电压集合，所述多个采样点对应的时间值的集合定义为时间集合；并且所述计算所述时间修正值可以包括：根据预设修正模型计算所述时间修正值，所述预设修正模型为所述电压集合和所述时间集合的函数。进一步地，所述预设修正模型的函数形式包括以下中的至少一项：高斯函数、多项式函数、神经网络。进一步地，所述预设修正模型的参数通过如下方式求得：获取多个标定反射脉冲信号，每个所述标定反射脉冲信号所对应的时间真实值是已知的；对所述每个标定反射脉冲信号进行采样得到采样结果；基于所述每个标定反射脉冲信号的采样结果计算所述每个标定反射脉冲信号对应的时间测量值；基于所述每个标定反射脉冲信号的时间真实值和所述每个标定反射脉冲信号的时间测量值计算所述预设修正模型的参数。进一步地，所述计算所述反射脉冲信号对应的时间测量值，包括：计算所述时间集合的平均值，以得到所述时间测量值；计算所述时间集合的任一子集的平均值，以得到所述时间测量值；从所述时间集合中选择其中一值，以作为所述时间测量值。其中，上述时间测量值和时间修正值的计算方法与前文中描述的类似，为了简洁，此处不再赘述。
以上示例性地描述了根据本发明实施例的测量方法。下面结合图9到图10描述根据本发明另一方面提供的测量装置900和1000。根据本发明实施例的测量装置900和1000可以分别用于实施上文中描述的根据本发明实施例的测量方法400和700，也均可以用于实施上文中描述的根据本发明实施例的测量方法400和700的结合。为了简洁，下文中仅对测量装置900和1000的主要结构和功能进行描述，而省略上文中已经描述的部分具体细节。
如图9所示，测量装置900可以包括发射器910、接收器920、采样 装置930和处理器940，其中，发射器910用于向被测物发射光脉冲信号。接收器920用于接收所述光脉冲信号对应的反射脉冲信号。采样装置930用于对所述反射脉冲信号进行采样得到采样结果。处理器940用于基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值，基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
如图10所示，测量装置1000可以包括发射器1010、接收器1020、采样装置1030和处理器1040，其中，发射器1010用于向被测物发射光脉冲信号。接收器1020用于接收所述光脉冲信号对应的多个反射脉冲信号。采样装置1030用于对所述多个反射脉冲信号中的每一个进行采样得到采样结果。处理器1040用于对于每个所述反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响，如果确定受到影响，则基于所述反射脉冲信号的采样结果中的部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
根据本发明的又一方面，还提供了一种可移动平台。下面结合图11描述根据本发明又一方面提供的可移动平台1100的示意性框图。如图11所示，可移动平台1100可以包括机身1110、动力系统1120和测量装置1130。其中，动力系统1120可以安装在机身1110上，用于提供飞行动力。测量装置1130可以安装在机身1110上，用于感知可移动平台1100所处的环境并生成点云信息。测量装置1130可以是前文中所述的测量装置900或测量装置1000。示例性地，可移动平台1100可以为无人机。
根据本发明的再一方面，还提供了一种计算机可读介质，所述计算机可读介质上存储有计算机程序，所述计算机程序在运行时执行根据本发明实施例的测量方法。所述计算机可读介质例如可以包括智能电话的存储卡、平板电脑的存储部件、个人计算机的硬盘、只读存储器(ROM)、可擦除可编程只读存储器(EPROM)、便携式紧致盘只读存储器(CD-ROM)、USB存储器、或者上述存储介质的任意组合。所述计算机可读存储介质可以是一个或多个计算机可读存储介质的任意组合。
基于上面的描述，根据本发明实施例的测量方法、装置、可移动平台和计算机可读介质在计算光脉冲信号和其对应的反射脉冲信号之间的时间 间隔时考虑了脉冲畸变问题，不仅计算反射脉冲信号对应的时间测量值，还计算相应的时间修正值，并基于时间测量值和时间修正值计算得到时间间隔的最终结果，能够有效克服由于脉冲失真、畸变引进的测量误差，提高测量准确度。进一步地，根据本发明实施例的测量方法、装置、可移动平台和计算机可读介质考虑了接收到多脉冲信号的情况时一个反射脉冲信号是否受到相邻反射脉冲信号的影响的问题，如果确定了该反射脉冲信号受到了相邻反射脉冲信号的影响，则仅基于其他未受影响部分的采样结果进行时间间隔的计算，能够有效提高测量的准确度。
尽管这里已经参考附图描述了示例实施例，应理解上述示例实施例仅仅是示例性的，并且不意图将本发明的范围限制于此。本领域普通技术人员可以在其中进行各种改变和修改，而不偏离本发明的范围和精神。所有这些改变和修改意在被包括在所附权利要求所要求的本发明的范围之内。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
在本申请所提供的几个实施例中，应该理解到，所揭露的设备和方法，可以通过其它的方式实现。例如，以上所描述的设备实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个设备，或一些特征可以忽略，或不执行。
在此处所提供的说明书中，说明了大量具体细节。然而，能够理解，本发明的实施例可以在没有这些具体细节的情况下实践。在一些实例中，并未详细示出公知的方法、结构和技术，以便不模糊对本说明书的理解。
类似地，应当理解，为了精简本发明并帮助理解各个发明方面中的一个或多个，在对本发明的示例性实施例的描述中，本发明的各个特征有时被一起分组到单个实施例、图、或者对其的描述中。然而，并不应将该本发明的方法解释成反映如下意图：即所要求保护的本发明要求比在权利要求中所明确记载的特征更多的特征。更确切地说，如相应的权利要求书所 反映的那样，其发明点在于可以用少于某个公开的单个实施例的所有特征的特征来解决相应的技术问题。因此，遵循具体实施方式的权利要求书由此明确地并入该具体实施方式，其中权利要求本身都作为本发明的单独实施例。
本领域的技术人员可以理解，除了特征之间相互排斥之外，可以采用任何组合对本说明书(包括伴随的权利要求、摘要和附图)中公开的所有特征以及如此公开的任何方法或者设备的所有过程或单元进行组合。除非另外明确陈述，本说明书(包括伴随的权利要求、摘要和附图)中公开的特征可以由提供相同、等同或相似目的的替代特征来代替。
此外，本领域的技术人员能够理解，尽管在此所述的一些实施例包括其它实施例中所包括的某些特征而不是其它特征，但是不同实施例的特征的组合意味着处于本发明的范围之内并且形成不同的实施例。例如，在权利要求书中，所要求保护的实施例的任意之一都可以以任意的组合方式来使用。
本发明的各个部件实施例可以以硬件实现，或者以在一个或者多个处理器上运行的软件模块实现，或者以它们的组合实现。本领域的技术人员应当理解，可以在实践中使用微处理器或者数字信号处理器(DSP)来实现根据本发明实施例的一些模块的一些或者全部功能。本发明还可以实现为用于执行这里所描述的方法的一部分或者全部的装置程序(例如，计算机程序和计算机程序产品)。这样的实现本发明的程序可以存储在计算机可读存储介质上，或者可以具有一个或者多个信号的形式。这样的信号可以从因特网网站上下载得到，或者在载体信号上提供，或者以任何其他形式提供。
应该注意的是上述实施例对本发明进行说明而不是对本发明进行限制，并且本领域技术人员在不脱离所附权利要求的范围的情况下可设计出替换实施例。在权利要求中，不应将位于括号之间的任何参考符号构造成对权利要求的限制。本发明可以借助于包括有若干不同元件的硬件以及借助于适当编程的计算机来实现。在列举了若干装置的单元权利要求中，这些装置中的若干个可以是通过同一个硬件项来具体体现。单词第一、第二、以及第三等的使用不表示任何顺序。可将这些单词解释为名称。
以上所述，仅为本发明的具体实施方式或对具体实施方式的说明，本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。本发明的保护范围应以权利要求的保护范围为准。

Claims (27)

  1. 一种测量方法，其特征在于，所述方法包括：
    向被测物发射光脉冲信号；
    接收所述光脉冲信号对应的反射脉冲信号；
    对所述反射脉冲信号进行采样得到采样结果；
    基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值，基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  2. 根据权利要求1所述的方法，其特征在于，所述采样结果包括多个采样点，每个采样点对应于一个电压值和一个时间值，所述多个采样点对应的电压值的集合定义为电压集合，所述多个采样点对应的时间值的集合定义为时间集合；并且
    基于所述采样结果计算所述时间修正值包括：根据预设修正模型计算所述时间修正值，所述预设修正模型为所述电压集合和所述时间集合的函数。
  3. 根据权利要求2所述的方法，其特征在于，所述预设修正模型的函数形式包括以下中的至少一项：高斯函数、多项式函数、神经网络。
  4. 根据权利要求2或3所述的方法，其特征在于，所述预设修正模型的参数通过如下方式求得：
    获取多个标定反射脉冲信号，每个所述标定反射脉冲信号所对应的时间真实值是已知的；
    对所述每个标定反射脉冲信号进行采样得到采样结果；
    基于所述每个标定反射脉冲信号的采样结果计算所述每个标定反射脉冲信号对应的时间测量值；
    基于所述每个标定反射脉冲信号的时间真实值和所述每个标定反射脉冲信号的时间测量值计算所述预设修正模型的参数。
  5. 根据权利要求2-4中的任一项所述的方法，其特征在于，基于所述采样结果计算所述反射脉冲信号对应的时间测量值包括以下中的任一项：
    计算所述时间集合的平均值，以得到所述时间测量值；
    计算所述时间集合的任一子集的平均值，以得到所述时间测量值；
    从所述时间集合中选择其中一值，以作为所述时间测量值。
  6. 根据权利要求1-5中的任一项所述的方法，其特征在于，所述接收所述光脉冲信号对应的反射脉冲信号包括：接收所述光脉冲信号对应的多个反射脉冲信号，并且所述基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值进一步包括：
    对于所述多个反射脉冲信号中的每个反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响；
    如果确定受到相邻反射脉冲信号的影响，则基于所述采样结果中的部分数据计算所述反射脉冲信号对应的时间测量值和时间修正值。
  7. 根据权利要求6所述的方法，其特征在于，所述对所述反射脉冲信号进行采样包括：
    对所述反射脉冲信号进行多路采样，每一路采样得到一个上升沿采样点和一个下降沿采样点，所述上升沿采样点和所述下降沿采样点具有相同的电压值和不同的时间值。
  8. 根据权利要求7所述的方法，其特征在于，基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值进一步包括：
    当确定所述反射脉冲信号受到前一个反射脉冲信号的影响时，基于所述多路采样得到的下降沿采样点计算所述反射脉冲信号对应的时间测量值和时间修正值。
  9. 根据权利要求7或8所述的方法，其特征在于，基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值进一步包括：
    当确定所述反射脉冲信号受到后一个反射脉冲信号的影响时，基于所述多路采样得到的上升沿采样点计算所述反射脉冲信号对应的时间测量值和时间修正值。
  10. 根据权利要求6-9中的任一项所述的方法，其特征在于，所述方法还包括：
    如果确定未受到相邻反射脉冲信号的影响，则基于所述采样结果中的全部数据或部分数据计算所述反射脉冲信号对应的时间测量值和时间修正值。
  11. 根据权利要求1-10中的任一项所述的方法，其特征在于，所述对 所述反射脉冲信号进行采样是基于时间数字转换器或模拟数字转换器实现的。
  12. 一种测量方法，其特征在于，所述方法包括：
    向被测物发射光脉冲信号；
    接收所述光脉冲信号对应的多个反射脉冲信号；
    对所述多个反射脉冲信号中的每一个进行采样得到采样结果；
    对于每个所述反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响，如果确定受到影响，则基于所述反射脉冲信号的采样结果中的部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  13. 根据权利要求12所述的方法，其特征在于，所述对所述多个反射脉冲信号中的每一个进行采样包括：
    对每个所述反射脉冲信号进行多路采样，每一路采样得到一个上升沿采样点和一个下降沿采样点，所述上升沿采样点和所述下降沿采样点具有相同的电压值和不同的时间值。
  14. 根据权利要求13所述的方法，其特征在于，所述相邻反射脉冲信号包括所述反射脉冲信号的前一个反射脉冲信号，如果确定受到所述前一个反射脉冲信号的影响，则基于所述多路采样得到的下降沿采样点计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  15. 根据权利要求13或14所述的方法，其特征在于，所述相邻反射脉冲信号包括所述反射脉冲信号的后一个反射脉冲信号，如果确定受到所述后一个反射脉冲信号的影响，则基于所述多路采样得到的上升沿采样点计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  16. 根据权利要求12所述的方法，其特征在于，所述方法还包括：
    如果确定所述反射脉冲信号未受到相邻反射脉冲信号的影响，则基于所述反射脉冲信号的采样结果中的全部数据或部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  17. 根据权利要求12-16中的任一项所述的方法，其特征在于，所述计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔包括：
    计算所述反射脉冲信号对应的时间测量值和时间修正值，并基于所述 时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  18. 根据权利要求17所述的方法，其特征在于，所述采样结果包括多个采样点，每个采样点对应于一个电压值和一个时间值，所述多个采样点对应的电压值的集合定义为电压集合，所述多个采样点对应的时间值的集合定义为时间集合；并且
    所述计算所述时间修正值包括：根据预设修正模型计算所述时间修正值，所述预设修正模型为所述电压集合和所述时间集合的函数。
  19. 根据权利要求18所述的方法，其特征在于，所述预设修正模型的函数形式包括以下中的至少一项：高斯函数、多项式函数、神经网络。
  20. 根据权利要求18或19所述的方法，其特征在于，所述预设修正模型的参数通过如下方式求得：
    获取多个标定反射脉冲信号，每个所述标定反射脉冲信号所对应的时间真实值是已知的；
    对所述每个标定反射脉冲信号进行采样得到采样结果；
    基于所述每个标定反射脉冲信号的采样结果计算所述每个标定反射脉冲信号对应的时间测量值；
    基于所述每个标定反射脉冲信号的时间真实值和所述每个标定反射脉冲信号的时间测量值计算所述预设修正模型的参数。
  21. 根据权利要求18-20中的任一项所述的方法，其特征在于，所述计算所述反射脉冲信号对应的时间测量值，包括：
    计算所述时间集合的平均值，以得到所述时间测量值；
    计算所述时间集合的任一子集的平均值，以得到所述时间测量值；
    从所述时间集合中选择其中一值，以作为所述时间测量值。
  22. 根据权利要求12-21中的任一项所述的方法，其特征在于，所述对所述多个反射脉冲信号中的每一个进行采样是基于时间数字转换器或模拟数字转换器实现的。
  23. 一种测量装置，其特征在于，所述测量装置包括发射器、接收器、采样装置和处理器，其中：
    所述发射器用于向被测物发射光脉冲信号；
    所述接收器用于接收所述光脉冲信号对应的反射脉冲信号；
    所述采样装置用于对所述反射脉冲信号进行采样得到采样结果；
    所述处理器用于基于所述采样结果计算所述反射脉冲信号对应的时间测量值和时间修正值，基于所述时间测量值和所述时间修正值计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  24. 一种测量装置，其特征在于，所述测量装置包括发射器、接收器、采样装置和处理器，其中：
    所述发射器用于向被测物发射光脉冲信号；
    所述接收器用于接收所述光脉冲信号对应的多个反射脉冲信号；
    所述采样装置用于对所述多个反射脉冲信号中的每一个进行采样得到采样结果；
    所述处理器用于对于每个所述反射脉冲信号，确定所述反射脉冲信号是否受到相邻反射脉冲信号的影响，如果确定受到影响，则基于所述反射脉冲信号的采样结果中的部分数据计算所述光脉冲信号和所述反射脉冲信号之间的时间间隔。
  25. 根据权利要求23或24所述的测量装置，其特征在于，所述测量装置是激光雷达。
  26. 一种可移动平台，其特征在于，所述可移动平台包括：
    机身；
    动力系统，安装在所述机身上，用于提供飞行动力；
    如权利要求23-25中的任一项所述的测量装置，安装在所述机身上，用于感知所述可移动平台所处的环境并生成点云信息。
  27. 一种计算机可读介质，其特征在于，所述计算机可读介质上存储有计算机程序，所述计算机程序在运行时执行如权利要求1-22中的任一项所述的测量方法。
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