WO2021046768A1 - 一种目标物的反射率计算方法、装置及相关设备 - Google Patents

一种目标物的反射率计算方法、装置及相关设备 Download PDF

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WO2021046768A1
WO2021046768A1 PCT/CN2019/105439 CN2019105439W WO2021046768A1 WO 2021046768 A1 WO2021046768 A1 WO 2021046768A1 CN 2019105439 W CN2019105439 W CN 2019105439W WO 2021046768 A1 WO2021046768 A1 WO 2021046768A1
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echo signal
sub
signal
echo
impulse response
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PCT/CN2019/105439
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English (en)
French (fr)
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刘彤辉
李强
姜彤
李洪磊
巫红英
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华为技术有限公司
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Priority to CN201980057942.4A priority Critical patent/CN112789522B/zh
Priority to PCT/CN2019/105439 priority patent/WO2021046768A1/zh
Publication of WO2021046768A1 publication Critical patent/WO2021046768A1/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

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  • This application relates to the field of radar, and in particular to a method, device and related equipment for calculating the reflectivity of a target.
  • Reflectance is one of the inherent properties of an object.
  • the reflectance can be used to identify object materials. For example, when a vehicle-mounted radar recognizes a road sign, the road sign can be recognized by calculating the reflectance of different colors on the road sign; When lidar recognizes unidentified flying objects in the air, the type of flying objects can be recognized by determining the reflectivity of flying objects in the target airspace. Therefore, the calculation of reflectivity can be applied to fields such as intelligent transportation, autonomous driving, atmospheric environment monitoring, geographic surveying and mapping, and UAV reconnaissance.
  • Target irradiation characteristic modeling method which is based on the bidirectional reflectance distribution function (Bidirectional Reflectance Distrbtion Tunction, BRDF) and other methods to model the target's reflection characteristics Then, the energy, composition, and polarization state of the reflected light of the target object under Lambertian reflection can be obtained more accurately, and then the reflectance of the target object can be calculated based on the above information.
  • the intensity information inversion method This method needs to accurately know the intensity information of the target's echo, bring it into the radar equation and decouple other parameters to obtain the reflectance information.
  • the second method does not need to model the target reflection information, and can obtain more accurate reflectance information through a simple algorithm, which can be applied in a real-time processing system.
  • the first method mentioned above needs to know the incident angle, roughness and other information when modeling the reflection characteristics of the target, and the model used in this method is complex and requires certain calibration work, which often requires offline calculation. Therefore, it is difficult to apply in real-time processing systems.
  • the above-mentioned second method can be applied to a real-time processing system, the echo signal intensity information used in the estimation is easily affected by factors such as the angle of incidence on the target, the geometric shape of the target, and so on. This leads to the introduction of relatively large deviations in the calculation process of this method, which in turn brings difficulties to the accurate calculation of reflectivity.
  • the embodiments of the present application provide a method, device and related equipment for calculating the reflectance of a target object, so as to calculate the reflectance of the object simply and accurately in a real-time processing system.
  • an embodiment of the present application provides a method for calculating the reflectance of a target object, which may include: extracting n-part echo signals from the echo signals reflected by the target object received at the receiving end, wherein the n-part echo signals are The time interval for each two adjacent sub-echo signals in the signal to reach the receiving end is greater than the preset first time interval, n is a positive integer greater than or equal to 1; calculate the sub-reflection of each sub-echo signal in the n-part echo signal Rate; accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target.
  • the embodiment of the present application can extract n parts of the echo signal from the echo signal of the target object received by the receiving end, and then calculate the part of each of the n parts of the echo signal. Reflectance, and finally accumulate the n-component reflectance to obtain the reflectance of the object or target in the target area.
  • the signal strength reflected by this part back to the receiving end is all signals with similar and close time intervals.
  • the target has two parts with different distances, even if the two parts have the same material and shape, as long as the distances from the receiving end are different, the time to reach the receiving end will also be different, and then the two parts The time interval of the signal reflected back to the receiving end is greater than the preset first time interval. Therefore, the two parts cannot be considered to be the same part of the same target. Therefore, if the receiving end receives any two echoes reflected back from the target within the preset first time interval, it can be considered that the two echoes can belong to the same part of the same target reflected back to the receiving end. Sub-echo signal.
  • the embodiment of the present application can extract n sub-echo signals from the echo signal reflected by the target object received by the receiving end according to the above-mentioned rules.
  • a sub-echo signal represents an object or a certain part of an object.
  • the process of transmitting the signal is regarded as a system, and the overall response of the system is gradually decoupled, and then the method of inversion is performed to calculate the reflectivity, which is different from the existing technology to calculate the reflection.
  • the error of reflectance estimation can be limited to a relatively small range, which effectively solves the problem of ambiguity in reflectance estimation caused by the shape of the target and the angle of incidence.
  • the n-part echo signal extracted from the echo signal reflected by the target object received by the receiving end can be extracted from the echo signal that meets the conditions, and divided into The n-part echo signal can also be selected from all the sub-echo signals that meet the conditions, where n parts of the signal are selectively extracted as the sub-echo signal, and n is a positive integer greater than or equal to 1. Therefore, the echo signal is extracted from the n-part echo signal, the sub-reflectivity of the n-part echo signal is calculated and then accumulated to obtain the reflectivity of the entire target, which avoids the calculation of the incident angle and the geometric shape of the target due to the transmitted signal.
  • the influence of the reflectance of the target object, and the method is simple, and can be applied in a real-time processing system to calculate the reflectance of the object simply and accurately, which improves the accuracy and efficiency of the calculation of the reflectance.
  • the signal strength of each of the n-part echo signals is greater than the signal strength threshold.
  • the signal strength threshold can be set to the signal strength corresponding to the false alarm probability of one thousandth.
  • the false alarm probability refers to the process of lidar detection
  • the threshold detection method due to the ubiquitous existence and fluctuation of noise, it will increase the probability that there is no target object but it is judged by the lidar as a target object. Therefore, the signal strength of each sub-echo signal is greater than the signal strength threshold, which can effectively reduce the influence of other interference on the calculation of the reflectance of the target, and improve the accuracy of calculating the reflectance of the object.
  • the method before extracting the n-part echo signal from the echo signal reflected by the target object received by the receiving end, the method further includes: applying the least square method or the least mean square error method to the echo signal Perform response estimation to obtain m impulse responses corresponding to the echo signal, where m is a positive integer greater than or equal to 1; after extracting the n-component echo signal from the echo signal reflected by the target object received at the receiving end, it also includes : According to m impulse responses, calculate the impulse response value of one or more impulse responses corresponding to each sub-echo signal in the n-component echo signal; calculate the value of each sub-echo signal in the n-component echo signal
  • the sub-reflectivity includes calculating the sub-reflectivity of the corresponding sub-echo signal according to the impulse response value of one or more impulse responses corresponding to each sub-echo signal.
  • the echo signal before extracting the n-component echo signal, can be converted from a time domain signal to a frequency domain signal.
  • the impulse response can be convolved with the transmitted signal to obtain the echo that is reflected back to the receiving end.
  • the impulse response corresponding to the echo signal can intuitively show the signal strength of the transmitted signal reflected by the target at a certain moment, that is, the impulse response value of one or more impulse responses corresponding to the sub-echo signal , Can represent the signal strength of the target object represented by the sub-echo signal reflecting the transmitted signal back to the receiving end at a certain moment.
  • each of the above sub-echoes represents any one of a plurality of objects that meet the preset distance threshold or a different part of an object that meets the preset distance threshold.
  • the time delay of the impulse response of the sub-echo signal represents The shape and incident angle characteristics of the object
  • the amplitude of the impulse response represents the reflectivity characteristics of the object
  • the sum of the amplitude of the impulse response corresponding to the sub-echo represents the intensity of the reflectivity of the object
  • each sub-echo impulse The superimposition of the response amplitude represents the average reflectivity of a transmitted pulse or signal to the target object.
  • extracting the n-part echo signal from the echo signal reflected by the target received by the receiving end includes: determining z impulse response sets according to the m impulse responses, where each The time interval between any two adjacent impulse responses among the multiple impulse responses included in one impulse response set is within the preset second time interval, any two impulse responses in z impulse response sets The intersection between the sets is an empty set, the preset second time interval is a preset time interval less than the preset first time interval, z is a positive integer greater than or equal to n, and m is a positive integer greater than or equal to z; After removing the impulse responses of each impulse response set of z impulse response sets whose impulse response value is less than the response threshold, n impulse response sets are obtained, n impulse response sets and n component echo signals one by one Corresponds, and includes the impulse response corresponding to the n-component echo signal.
  • n impulse response sets are determined from m impulse responses, and each impulse response set in the n impulse response sets corresponds to a sub-echo signal of the n-echo signals, respectively,
  • Each impulse response set in the n impulse response sets includes one or more impulse responses whose impulse response values are greater than the response threshold, and the one or more impulse responses are comparable to those in the m impulse responses.
  • the time interval between at least one adjacent impulse response is smaller than the preset second time interval.
  • the embodiment of the present application accurately determines the echo from the same target or the same part of the target from multiple targets or targets with irregular geometric shapes, thereby avoiding the subsequent calculation process of reflectivity.
  • the influence of factors such as the geometric shape of the medium target and the angle of incidence improves the calculation accuracy of the reflectance.
  • extracting the n-part echo signal from the echo signal reflected by the target object received by the receiving end includes: determining k signal sets according to the echo signal, wherein, in each signal set The time interval for every two adjacent echoes in the included multiple echoes to reach the receiving end is within the preset third time interval, the intersection between any two signal sets in the k signal sets is an empty set, and k is greater than Or a positive integer equal to n; determine the amplitude threshold of all echoes in each signal set of k signal sets; remove all echoes whose amplitude threshold is less than the preset amplitude threshold threshold in each signal set of k signal sets, Obtain n signal sets, and the n signal sets have a one-to-one correspondence with the n component echo signals.
  • each signal set corresponds to a subset of the n echo signals
  • each signal set in the n signal sets Each includes one or more echoes whose amplitude thresholds are all greater than the preset amplitude threshold threshold, and the time interval between the one or more echoes and at least one adjacent echo when they reach the receiving end is less than the preset third Time interval
  • this amplitude threshold can be the false alarm threshold of the lidar or other thresholds.
  • a certain amplitude threshold such as: false alarm threshold or other thresholds
  • the embodiment of the present application extracts the sub-echo signals that meet the amplitude threshold in the signal set, and can more accurately determine the signal from multiple targets in the target area or targets with irregular geometric shapes. The echo of the real target object, thereby avoiding the influence of factors such as the interference target object in the subsequent calculation process of the reflectivity, and improving the calculation accuracy of the reflectivity.
  • each sub-echo signal in the n-part echo signal before calculating the sub-reflectivity of each sub-echo signal in the n-part echo signal, it further includes: determining all the impulses corresponding to each sub-echo signal in the n-part echo signal.
  • Impulse response value of the shock response calculate the sub reflectivity of each sub-echo signal in the n-molecular echo signal, including: impulse response according to all the impulse responses in each sub-echo signal in the n-molecular echo signal Calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal.
  • the impulse response value of all the corresponding impulse responses in each sub-echo signal in the extracted n-component echo signal it is necessary to determine the impulse response value of all the corresponding impulse responses in each sub-echo signal in the extracted n-component echo signal, and then calculate each impulse response value according to the impulse response value.
  • the sub-reflectivity of the echo signal of the molecule The impulse response corresponding to the sub-echo signal can intuitively show the signal strength of the transmitted signal reflected back to the target at a certain moment.
  • the different time delays of the impulse response represent the difference in the distance between the target and the receiving end.
  • the number of impulse responses corresponding to the echo signal can also represent the number of allocated shares of the reflected signal energy, that is, the signal reflected by the target object back to the receiving end will be allocated to several shares with different time delays and different energies. Therefore, the method of calculating the reflectivity using the impulse response of the target can be used in the real-time processing system to simply and accurately calculate the reflectivity of the object.
  • the above calculation of the sub-reflection of each sub-echo signal in the n-component echo signal is based on the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal Rate, including: determining the first ratio according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, and the effective receiving area of the receiving end; the ratio of all the impulse responses in each sub-echo signal in the n-component echo signal The impulse response value and the first ratio are respectively multiplied and then accumulated to obtain the sub-reflectivity of each sub-echo signal in the n-echo signal.
  • the first ratio is first determined according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, the effective receiving area of the receiving end, etc., because the first ratio can represent the reflected echo signal in the atmosphere and The receiving end is affected by the impact, so the first ratio is multiplied by the impulse response value representing the ratio of the received signal to the transmitted signal, and the sub-reflection of each sub-echo signal in the n-part echo signal obtained by calculation is accumulated.
  • the rate can be more precise, where the impulse response value is the amplitude value of the impulse response.
  • This method of calculating reflectivity using the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, the effective receiving area of the receiving end, and the impulse response of the target object can be used to calculate the object simply and accurately in the real-time processing system of real life. ⁇ Reflectivity.
  • the above calculation of the sub-reflection of each sub-echo signal in the n-component echo signal is based on the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal
  • the rate includes: according to the impulse response value of all the impulse responses in each sub-echo signal in the n-component echo signal, calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal through the sub-reflectivity calculation formula , Where the sub-reflectivity calculation formula is: Where ⁇ i is the sub-reflectivity of the i-th component echo signal in the n-component echo signal, ⁇ a is the single-pass transmittance of the laser in the atmosphere, ⁇ r is the efficiency of the receiving optical system, and A r is the The effective receiving area of the receiving end, ⁇ is the angle between the optical axis of the transmitting optical system of the transmitting end and the target normal ON, and R ij is the target corresponding
  • the impact The shock response value h ij refers to the magnitude of the impulse response.
  • the sub-reflectance calculation formula is the reflectance calculation formula inverted by the radar equation.
  • the impulse response value regarded as an impulse response is used to represent the signal strength reflected by the target at a certain moment, so it can be based on the impulse response corresponding to the jth impulse response in the i-th component echo signal
  • the echo signal of the i-th molecule obtained by the value corresponds to the reflectance information of the target, which reduces the difficulty of calculating the reflectance.
  • the impulse response value of all the impulse responses in each sub-echo signal in the n-part echo signal removes one or more of the above-mentioned receiving end, channel, and transmitting end.
  • influencing factors include one or more of loss, filtering, and attenuation.
  • the loss, filtering or attenuation of devices such as avalanche photodiodes, transimpedance amplifiers, low-pass filters, analog-to-digital converters, etc., on the other hand, will also change the signal due to the efficiency and loss of the receiving end. Therefore, before calculating the sub-reflectance, these influencing factors need to be decoupled, and then the value of the impulse response after removing the influence is substituted into the formula calculation, and a more accurate reflectance result can be obtained. It is understandable that the value of the impulse response after the influence is removed is also the amplitude value of the impulse response, and the decoupling method includes but not limited to actual calibration, device and system modeling, or a combination of the two.
  • This method divides a whole into n parts and then accumulates them, and there is no need to know the incident angle, roughness and other information when calculating one part.
  • the model is simple and does not need to be calibrated, which can be better applied to real-time processing systems. , Simple and accurate calculation of the reflectivity of the object.
  • the above-mentioned preset first time interval is the time interval between two echo signals respectively reflected by two reflection points on the target and whose distance is greater than or equal to the preset distance threshold to reach the receiving end.
  • the preset first time interval is preset, the distance on the target object is greater than or equal to the preset distance threshold, two reflection points (the two reflection points may be different objects The two reflection points on the upper part can also be different reflection points on the same object.)
  • the time interval for the reflected echo signal to reach the receiving end is equivalent to the pulse width of the echo signal.
  • the reflection of the target object is calculated
  • the time interval between two adjacent sub-echo signals reaches the receiving end is greater than the preset first time interval, it is considered that the two reflection points belong to two different objects or different parts of the same object.
  • an embodiment of the present application provides a target reflectivity calculation device, which is characterized in that it includes:
  • the extracting unit is used to extract n parts of echo signals from the target reflected echo signal received by the receiving end, wherein the time interval of each two adjacent parts of the n parts of the echo signal to the receiving end is greater than
  • the first time interval is preset, and n is a positive integer greater than or equal to 1;
  • the sub-reflectivity unit is used to calculate the sub-reflectivity of each sub-echo signal in the aforementioned n-echo signals;
  • the reflectivity unit is used to accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target.
  • the signal strength of each of the n-part echo signals is greater than the signal strength threshold.
  • the above-mentioned device further includes: a response estimation unit for extracting the n-part echo signal from the echo signal reflected by the target object received from the receiving end through the least square method or the least average The variance method estimates the response of the echo signal to obtain m impulse responses corresponding to the echo signal, where m is a positive integer greater than or equal to 1; the first determining unit is used to reflect the target object received from the receiving end After extracting the n-component echo signal from the echo signal of, calculate the impulse response value of one or more impulse responses corresponding to each sub-echo signal in the n-component echo signal according to the m impulse responses; calculate;
  • the sub-reflectivity of each sub-echo signal in the n-component echo signal includes: calculating the sub-reflectivity of the corresponding sub-echo signal according to the impulse response value of one or more impulse responses corresponding to each sub-echo signal .
  • the extraction unit is specifically configured to: determine z impulse response sets according to the m impulse responses, where any of the multiple impulse responses included in each impulse response set The time interval between two adjacent impulse responses is within a preset second time interval, the intersection between any two impulse response sets in the z impulse response sets is an empty set, and the preset second time interval The interval is a preset time interval that is less than the preset first time interval, z is a positive integer greater than or equal to n, and m is a positive integer greater than or equal to z; each impulse response of the above z impulse response sets is removed After impulse responses with impulse response values less than the response threshold in the set are obtained, n impulse response sets are obtained.
  • the n impulse response sets correspond to the n component echo signals in a one-to-one correspondence, and include the corresponding n component echo signals. The impulse response.
  • the above-mentioned extraction unit is specifically configured to: determine k signal sets according to the above-mentioned echo signals, where every two adjacent echoes among the multiple echoes included in each signal set arrive The time interval of the receiving end is within a preset third time interval, the intersection between any two signal sets in the k signal sets is an empty set, and k is a positive integer greater than or equal to n; the determination of the above k signal sets The amplitude thresholds of all echoes in each signal set; after removing all the echoes whose amplitude thresholds are less than the preset amplitude threshold threshold in each signal set of the above k signal sets, n signal sets are obtained, and the above n signal sets are combined with The above-mentioned n-component echo signals have a one-to-one correspondence.
  • the above-mentioned apparatus further includes: a second determining unit, configured to determine the above-mentioned n-part echo signal before calculating the sub-reflectivity of each part of the above-mentioned n-part echo signal The impulse response values of all the corresponding impulse responses in each sub-echo signal in each sub-echo signal; the above-mentioned sub-reflectivity unit is specifically used to: according to the impulse response values of all the impulse responses in each sub-echo signal in the n-echo signal Calculate the sub-reflectivity of each sub-echo signal in the above-mentioned n-echo signal.
  • the aforementioned sub-reflectance unit is specifically used to determine the first ratio according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, and the effective receiving area of the receiving end;
  • the impulse response values of all the impulse responses in each sub-echo signal in the signal are respectively multiplied by the first ratio and then accumulated to obtain the sub-reflectivity of each sub-echo signal in the n-echo signal.
  • the above-mentioned sub-reflectance unit is specifically used to calculate n according to the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal through the sub-reflectance calculation formula.
  • ⁇ i is the sub-reflectivity of the i-th component echo signal in the above-mentioned n-component echo signal
  • ⁇ a is the single-pass transmittance of the laser in the atmosphere
  • ⁇ r is the efficiency of the receiving optical system
  • a r is the above-mentioned receiving end Effective receiving area
  • ⁇ is the angle between the optical axis of the transmitting optical system at the transmitting end and the target normal ON
  • R ij is the distance between the target corresponding to the jth impulse response in the i-th component echo signal and the receiving end distance
  • P Rij is the laser receiving power corresponding to the jth impulse response in the i-th component echo signal
  • P Tij is the laser emission power corresponding
  • the impulse response value of all the impulse responses in each sub-echo signal in the n-part echo signal removes one or more of the above-mentioned receiving end, channel, and transmitting end.
  • the above-mentioned influencing factors include one or more of loss, filtering, and attenuation.
  • the above-mentioned preset first time interval is the time interval between two echo signals respectively reflected by two reflection points on the target and whose distance is greater than or equal to the preset distance threshold to reach the receiving end.
  • an embodiment of the present application provides a lidar, which is characterized by comprising: a receiving end and a processor; wherein the receiving end is used to receive the echo signal reflected by a target; the processor is used to : Extracting n-part echo signals from the echo signal reflected by the target object received by the receiving end, wherein the time interval for each two adjacent sub-echo signals in the n-part echo signal to reach the receiving end is greater than the preset first A time interval, where n is a positive integer greater than or equal to 1; calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal; accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target .
  • the receiving end is specifically used to receive the analog echo signal reflected by the target;
  • the lidar further includes a detector, and the receiving end and the processor are respectively coupled with the detector;
  • the detection The processor is used to perform analog-to-digital conversion of the analog echo signal received by the receiving end, and send the echo signal after the analog-to-digital conversion to the processor;
  • the processor is specifically used to: perform analog-to-digital conversion from the foregoing From the converted echo signal, n component echo signals are extracted, wherein the time interval of the analog echo signal corresponding to each adjacent two component echo signals in the n component echo signal to the receiving end is greater than the preset first Time interval, n is a positive integer greater than or equal to 1; calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal; accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target.
  • the signal strength of each of the n-part echo signals is greater than the signal strength threshold.
  • the above-mentioned processor is also used for: using the least square method or the least mean square error The method performs response estimation on the echo signal, and obtains m impulse responses corresponding to the echo signal, where m is a positive integer greater than or equal to 1; the processor is used in the echo signal reflected by the target object received from the receiving end
  • the above-mentioned processor is further used to calculate the impulse response value of one or more impulse responses corresponding to each component of the n-component echo signal according to the m impulse responses ;
  • Calculating the sub-reflectivity of each sub-echo signal in the n-component echo signal includes: calculating the corresponding sub-echo signal's sub-echo signal according to the impulse response value of one or more impulse responses corresponding to each sub-echo signal Reflectivity.
  • the above-mentioned processor when used to extract n parts of the echo signal from the echo signal reflected by the target object received by the receiving end, the above-mentioned processor is specifically used to: determine according to the above-mentioned m impulse responses z impulse response sets, where the time interval between any two adjacent impulse responses of the multiple impulse responses included in each impulse response set is within a preset second time interval, and the z The intersection between any two impulse response sets in the impulse response set is an empty set, the above-mentioned preset second time interval is a preset time interval less than the preset first time interval, and z is a positive integer greater than or equal to n , And m is a positive integer greater than or equal to z; after removing the impulse responses whose impulse response value is less than the response threshold in each impulse response set of the z impulse response sets, n impulse response sets are obtained.
  • the n impulse response sets have a one-to-one correspondence with the aforementioned n-part echo signals,
  • the above-mentioned processor when the above-mentioned processor is used for extracting n-part echo signals from the echo signals reflected by the target object received by the receiving end, the above-mentioned processor is specifically used for: determining k pieces according to the above-mentioned echo signals.
  • a signal set where the time interval for each of the multiple echoes included in each signal set to reach the receiving end is within a preset third time interval, and any two signals in the k signal sets The intersection between the sets is an empty set, and k is a positive integer greater than or equal to n; determine the amplitude threshold of all echoes in each of the above k signal sets; remove each of the above k signal sets After all the echoes whose amplitude threshold is less than the preset amplitude threshold threshold, n signal sets are obtained, and the above n signal sets correspond to the above n component echo signals in a one-to-one correspondence.
  • the above-mentioned processor is also used to: determine each of the n-part echo signals.
  • the impulse response values of all the corresponding impulse responses in the molecular echo signal when the above-mentioned processor is used to calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal, the above-mentioned processor is specifically used to: The impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal are calculated, and the sub-reflectivity of each sub-echo signal in the n-component echo signal is calculated.
  • the above-mentioned processor is configured to calculate each of the n-component echo signals according to the impulse response values of all the impulse responses in each of the n-component echo signals.
  • the above-mentioned processor is specifically used to determine the first ratio according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, and the effective receiving area of the receiving end;
  • the impulse response values of all the impulse responses in the sub-echo signal are respectively multiplied by the first ratio and then accumulated to obtain the sub-reflectivity of each sub-echo signal in the n-echo signal.
  • the above-mentioned processor is configured to calculate each of the n-component echo signals according to the impulse response values of all the impulse responses in each of the n-component echo signals.
  • the above-mentioned processor is specifically used to calculate the n-component echo according to the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal through the sub-reflectivity calculation formula
  • the sub-reflectivity of each sub-echo signal in the signal where the sub-reflectivity calculation formula is:
  • ⁇ i is the sub-reflectivity of the i-th component echo signal in the above-mentioned n-component echo signal
  • ⁇ a is the single-pass transmittance of the laser in the atmosphere
  • ⁇ r is the efficiency of the receiving optical system
  • a r is the above-mentioned receiving end Effective receiving area
  • ⁇ is the angle between the optical axis of the transmit
  • the impulse response value of all the impulse responses in each sub-echo signal in the n-part echo signal removes one or more of the above-mentioned receiving end, channel, and transmitting end.
  • the above-mentioned influencing factors include one or more of loss, filtering, and attenuation.
  • the above-mentioned processor when used to accumulate n-part reflectance to obtain the reflectance of the target object, the above-mentioned processor is specifically used to: accumulate n-part reflectance to obtain the reflectance of the target object according to the reflectance calculation formula.
  • the above-mentioned preset first time interval is the time interval between two echo signals respectively reflected by two reflection points on the target and whose distance is greater than or equal to the preset distance threshold to reach the receiving end.
  • an embodiment of the present application provides a service device that includes a processor, and the processor is configured to support the service device to perform a corresponding function in the method for calculating reflectance of a target provided in the first aspect .
  • the service device may further include a memory, which is used for coupling with the processor, and stores the necessary program instructions and data of the service device.
  • the service device may also include a communication interface for the service device to communicate with other devices or a communication network.
  • the embodiments of the present application provide a computer program, the computer program includes instructions, when the computer program is executed by a computer, the computer can execute the above-mentioned second aspect of the reflectance calculation device of the target. Process.
  • an embodiment of the present application provides a computer storage medium for storing computer software instructions used in the reflectance calculation device for a target object provided in the second aspect above, which includes instructions for executing the design in the above aspect program.
  • an embodiment of the present application provides a chip system, and the chip system includes a processor for supporting a network device to implement the functions involved in the foregoing first aspect.
  • the chip system further includes a memory, and the memory is used to store program instructions and data necessary for the data sending device.
  • the chip system can be composed of chips, or include chips and other discrete devices.
  • an embodiment of the present application provides an electronic device, including the processing chip provided by any one of the implementations of the first aspect and a discrete device coupled to the chip.
  • FIG. 1 is a schematic flowchart of a method for calculating reflectance based on intensity inversion according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of energy estimation of reflectance provided by an embodiment of the present application.
  • Fig. 3 is an architecture diagram of a radar system based on an intensity inversion method provided by an embodiment of the present application.
  • Fig. 4 is a schematic diagram of a laser radar system framework provided by an embodiment of the present application.
  • FIG. 5A is a schematic flowchart of a method for calculating reflectance of a target provided by an embodiment of the present application.
  • FIG. 5B is a schematic diagram of determining n impulse response sets from m impulse responses according to an embodiment of the present application.
  • Fig. 5C is a waveform diagram of an echo signal provided by an embodiment of the present application.
  • FIG. 5D is a schematic diagram of the impulse response corresponding to the echo signal provided by an embodiment of the present application.
  • FIG. 5E is a comparison diagram of a calculation result of a target reflectance calculation method provided by an embodiment of the present application and a reflectance calculation method based on intensity inversion in the second solution.
  • FIG. 6 is a schematic flowchart of another method for calculating the reflectance of a target provided by an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a device for calculating reflectance of a target provided by an embodiment of the present application.
  • FIG. 8 is a schematic structural diagram of another target reflectance calculation device provided by an embodiment of the present application.
  • component used in this specification are used to denote computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution.
  • the component may be, but is not limited to, a process, a processor, an object, an executable file, an execution thread, a program, and/or a computer running on a processor.
  • the application running on the computing device and the computing device can be components.
  • One or more components may reside in processes and/or threads of execution, and components may be located on one computer and/or distributed among two or more computers.
  • these components can be executed from various computer readable media having various data structures stored thereon.
  • the component may be based on, for example, data having one or more data packets (for example, data from two components interacting with another component in a local system, a distributed system, and/or a network, for example, the Internet that interacts with other systems through signals) Signals are communicated through local and/or remote processes.
  • data packets for example, data from two components interacting with another component in a local system, a distributed system, and/or a network, for example, the Internet that interacts with other systems through signals
  • Signals are communicated through local and/or remote processes.
  • Reflectivity the ratio of the reflected radiant energy projected on the object to the total radiant energy projected on the object is called the reflectivity of the object. This is for all wavelengths and should be called total reflectance, usually referred to simply as reflectance.
  • Least Squares Method also known as Least Squares Method
  • Least Squares Method is a mathematical optimization technique that finds the best function match of the data by minimizing the sum of squares of errors.
  • the least square method can be used to easily obtain unknown data, and minimize the sum of squares of errors between the obtained data and the actual data.
  • Minimum Mean-Square Error is the minimum mean square error under a certain constraint.
  • the optimization goal of MMSE is to make the estimated value based on the received data and the target data equal The square error is minimized.
  • the mean-square error is a measure that reflects the degree of difference between the estimator and the estimator.
  • Echo which is reflected wave. Because the transmission of waves is actually the process of energy transmission, when the receiving end cannot completely absorb the energy of the wave (for example, when the impedance does not match), part of the energy of the wave will be reflected back, forming an echo. It refers to the signal that arrives at a given point through other ways different from the normal path. At this point, the signal has sufficient size and delay so that it can be noticed that it is different from the signal transmitted by the normal path.
  • Impulse response The zero-state response caused by the system under the excitation of the unit impulse function is called the "impulse response" of the system. It has a Fourier transform relationship with the transfer function of the system, and the impulse response is completely determined by the characteristics of the system itself, and has nothing to do with the excitation source of the system. It is a common way to express the characteristics of the system as a function of time. In a continuous-time system, any signal can be decomposed into the superposition of impulse signals with different delays, and then in the actual analysis, the differential equation can be solved by the circuit analysis method or the deconvolution method can be used to calculate the system Impulse response.
  • LiDAR Light Detection And Ranging
  • LiDAR is a radar system that emits laser beams to detect the location and speed of the target. Its working principle is to transmit a detection signal (laser beam) to the target, and then compare the received signal (target echo) from the target with the transmitted signal, and after proper processing, the relevant information of the target can be obtained, such as Target distance, azimuth, altitude, speed, attitude, and even shape and other parameters, so as to detect, track and identify aircraft, missiles and other targets.
  • It consists of a laser transmitter, an optical receiver, a turntable, and an information processing system.
  • the laser converts electrical pulses into light pulses and emits them.
  • the optical receiver restores the light pulses reflected from the target to electrical pulses and sends them to the display.
  • BRDF Bidirectional Reflectance Distribution Function
  • ADC Analog Digital Converter
  • analog-to-digital converter also referred to as “analog-to-digital converter”
  • ADC Analog Digital Converter
  • it In a computer control system, it must be controlled by various detection devices, using continuously changing voltage or current as an analog quantity, and providing relevant parameters (such as speed, pressure, temperature, etc.) of the controlled object at any time.
  • relevant parameters such as speed, pressure, temperature, etc.
  • Avalanche photodiode also known as avalanche photodiode or collapse photodiode, is a semiconductor photodetector whose principle is similar to a photomultiplier tube.
  • Trans-Impedance Amplifier is a type of amplifier, and the amplifier type is defined according to the type of its input and output signals.
  • A gain
  • Y the output
  • X the input
  • A Y (voltage)/X (current)
  • transimpedance amplifier a transimpedance amplifier
  • a low-pass filter allows low-frequency signals to pass, but attenuates (or reduces) the passage of signals with frequencies higher than the cutoff frequency.
  • the role of the low-pass filter in signal processing is equivalent to that of other fields such as the moving average in the financial field; both of these tools provide a smooth form of signal by eliminating short-term fluctuations and retaining long-term development trends. .
  • DFT Discrete Fourier Transform
  • time domain and frequency domain the sequences at both ends of the transform (time domain and frequency domain) are of finite length, but in fact these two sets of sequences should be regarded as the main value sequences of discrete periodic signals. Even if DFT is performed on a discrete signal of finite length, it should be regarded as a transformation of its period extension. In practical applications, fast Fourier transform is usually used to calculate DFT.
  • Wiener filter a linear filter with least squares as the optimal criterion. Under certain constraints, the square of the difference between its output and a given function (usually called the expected output) is minimized, and it can finally be transformed into a Toblitz equation solving problem through mathematical operations. Wiener filter is also called least square filter or least square filter, and it is currently one of the basic filtering methods.
  • DSP Digital Signal Processing
  • lidar is an optical remote sensing technology that uses electromagnetic waves from ultraviolet band to far-infrared band (250nm-11um) to obtain target-related information by detecting the characteristics of the scattered light of the target.
  • Lidar has high measurement accuracy, fine time and space resolution, and can complete functions such as ranging, target detection, tracking and imaging recognition. It can be applied to intelligent transportation, autonomous driving, atmospheric environment monitoring, geographic surveying and mapping, drones, etc. field.
  • the reflectance information of the target object can provide important information of various objects such as color, material, shape, etc., and provide important help for object segmentation and target recognition.
  • the techniques for calculating reflectance include the following schemes:
  • Solution 1 The method first obtains the first measured reflectance of the standard reflectance object, and then compares the real reflectance of the standard object with the measured reflectance, and calculates the optical path attenuation value of the standard object at that position.
  • the compensation value is calculated according to the optical path attenuation value, the first measured reflectivity is compensated, and the true reflectivity information is obtained.
  • the target irradiation characteristic modeling method based on the bidirectional reflection distribution function and other methods to model the target reflection characteristics, the energy, composition and polarization state of the reflected light under Lambertian reflection can be obtained more accurately.
  • FIG. 1 is a schematic flow chart of a reflectance calculation method based on intensity inversion provided by an embodiment of the present application
  • Figure 2 is a reflectance calculation method provided by an embodiment of the present application.
  • the schematic diagram of energy estimation is applicable to the reflectance calculation process of this scheme.
  • FIG. 3 is a diagram of the architecture of a radar system based on an intensity inversion method provided by an embodiment of the present application. As shown in FIG.
  • the lidar 10 receives the echo signal 322.
  • the detector 302 in the lidar 10 includes a photosensitive element 304, an amplifier 306, a time/digital converter 308, an integrator 310, and an analog/digital converter 312, etc.
  • the amplifier 306 includes a transimpedance amplifier 316 and a voltage gain amplifier 318.
  • the time/digital converter 308 and the corresponding data channel 324, and the analog/digital converter 312 and the corresponding data channel 326 all keep working after the transmission signal is sent until the reflection signal reception is completed. As shown in Figure 2, the time/digital converter 308 generates two stops (406, 410) for channel 1 and two stops (408, 412) for channel 2.
  • the slope of the signal can be calculated from these timestamps, and then the maximum value (ie, peak value) of the echo pulse can be estimated by methods such as linear fitting. Taking into account the existence of influencing factors such as noise, it may be inaccurate to estimate the reflected energy only depending on the output of the time/digital converter 308. Therefore, the existing solution may also include integration parallel to the time/digital converter 308 ⁇ 310.
  • the integrator 310 accumulates the charge generated by all the received reflected pulses and the noise during the receiving period, and the analog/digital converter 312 digitizes the accumulated charge of the integrator during the scanning interval.
  • the processor performs integrated processing on the digitized value of the integrator 310 and the data of the time/digital converter 308 to obtain reflectance information. This single peak point estimation or peak superposition method can be applied in a real-time processing system to estimate the reflectivity of the target object.
  • the above scheme 1 is suitable for scenarios with high reflectance requirements, and the above scheme 2 is suitable for real-time systems, which meets most of the reflectance calculation needs in today's life, but has the following disadvantages:
  • this solution is calibrated according to the standard reflectivity object (for example, the incident angle, roughness, etc. information) can be decoupled from various influencing factors to obtain accurate reflectivity information, but this method requires a lot of For calibration work, it is difficult to achieve accurate real-time output of reflectance in a complex environment, and the model used in this method is complex and requires certain calibration work, often requires offline calculation, so it is difficult to apply in real-time processing systems, and the application scenarios are limited.
  • the standard reflectivity object for example, the incident angle, roughness, etc. information
  • the time and angle of incidence of the transmitted signal on the target will be different, which will cause the receiving end to receive from the target.
  • the time of the echo reflected back by the object is different, that is, the time for different echo signals to reach the receiving end is different, and the distance that the echo signal travels when it reaches the receiving end is also different. Therefore, the echo signal intensity information used in the existing methods for reflectivity estimation is easily affected by factors such as the angle of incidence on the target, and the geometric shape of the target, which may result in the estimation process of the method. Introducing a relatively large deviation, which in turn brings difficulties to the accurate estimation of the reflectivity.
  • the reflectance calculation method provided in this application can be used to solve the problem that in a real-time system, the time when the transmitted signal is irradiated on the target and the angle of incidence are different, which causes the receiving end to receive the echo reflected from the target at a different time. , The impact on the strength of the echo signal, and how to calculate the reflectivity of the object simply and accurately in the real-time processing system.
  • FIG. 4 is a schematic diagram of a laser radar system framework provided by an embodiment of the present application.
  • the laser radar 20 includes a receiving end 401 and a processor 403, and may also include a detector 402.
  • the receiving end 401 is specifically configured to receive analog echo signals.
  • the receiving end of the lidar can be coupled by a receiver, various forms of photodetectors, and other related devices. Among them, the receiver can accurately measure the transmitted signal (such as light pulse) from the transmitter.
  • the photodetector can include a combination of photomultiplier tubes, semiconductor photodiodes, avalanche photodiodes, infrared and visible light multi-element detectors, etc., until the propagation time is reflected back to the receiving end. After the lidar receives the reflected light from the target object, it also needs to convert the optical signal into an electrical signal (ie, analog echo signal).
  • the receiving end 401 can obtain one frame of data in one scanning period, and each distance measurement unit in the receiving field of view (ie, the target area) in one frame of data is one pixel.
  • the processor 403 is specifically configured to extract n parts of the echo signal from the echo signal after the analog-to-digital conversion, wherein every two adjacent parts of the echo signal of the n parts of the echo signal
  • the time interval for the corresponding analog echo signal to reach the receiving end is greater than the preset first time interval, and n is a positive integer greater than or equal to 1; calculate the sub-reflectivity of each sub-echo signal in the n sub-echo signals ; Accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target.
  • the echo signal is extracted from the n-component echo signal, and the sub-reflectivity of the n-component echo signal is calculated and then accumulated to obtain the reflectivity of the entire target object, which avoids the influence of the incident angle of the transmitted signal and the geometric shape of the target object on the calculation target
  • the reflectance of the object is affected by the simple method, and the reflectance of the object can be calculated simply and accurately in the real-time processing system, which improves the accuracy and efficiency of the calculation of the reflectance.
  • the lidar 20 further includes a detector 402, and the receiving end 401 and the processor 403 are respectively coupled with the detector 402.
  • the detector 402 is configured to perform analog-to-digital conversion on the analog echo signal 420 received by the receiving end 401, and send the echo signal after the analog-to-digital conversion to the processor.
  • the detector 402 may further include a diode 412 (e.g., avalanche photodiode), an amplifier 422 (e.g., a transimpedance amplifier 452, a signal amplifier 462, etc.), a filter 432 (e.g., a low-pass filter), One or more of the analog-to-digital converters 442.
  • the detector After the detector receives the analog electrical signal from the receiving end, it can first perform photoelectric conversion through a diode; then input the photoelectrically converted analog electrical signal into the amplifier to obtain the amplified analog electrical signal; and then the amplified analog electrical signal The interference in the signal is filtered through the filter, and finally the analog electrical signal after the interference is filtered is converted into a digital signal through an analog-to-digital converter, so that the subsequent processor can process the data normally.
  • the echo signal 04 is amplified and filtered by an avalanche photodiode, a transimpedance amplifier, and a low-pass filter, and then digital-to-analog conversion is performed by an analog-to-digital converter, and then the converted echo signal is sent to the processor for signal processing.
  • the receiving end 401 and the detector 402 included in the lidar 20 can be integrated into a group of hardware devices.
  • the processor is specifically configured to: extract the n-component echo signal from the echo signal after analog-to-digital conversion, and calculate the n-component echo signal.
  • the sub-reflectivity of each sub-echo signal in the echo signal ; accumulate the n-component reflectivity to obtain the reflectivity of the target.
  • the time interval for the analog echo signal corresponding to each two adjacent sub-echo signals in the n-part echo signal to reach the receiving end is greater than a preset first time interval, and n is a positive integer greater than or equal to 1. That is, when the processor calculates the reflectivity based on the echo signal, the echo signal is all a digital signal.
  • the lidar system can obtain one frame of data in one scanning period, and each distance measurement unit in the receiving field of view in one frame of data is one pixel.
  • the entire echo information sampled by the analog-digital converter can be received, including information such as the delay, waveform, and peak value of the echo.
  • the impulse response of the entire system can be obtained by deconvolution.
  • the resulting impulse response is the total response of various parts or modules including the transmitting system, channel, target, receiving end, noise, etc., and they work together to make the signal have changes in amplitude, delay, and distortion.
  • the remaining part of the response of the transmitting system, channel, receiving end, noise, etc. other than the target object needs to be taken from the impulse response of the entire system experienced by the echo signal
  • the influence of the target material, color, shape and other factors can be accurately obtained, and then the reflectance of the target can be accurately estimated.
  • lidar system architecture in FIG. 1 is only a part of exemplary implementations in the embodiments of the present application, and the lidar system architecture in the embodiments of the present application includes but is not limited to the above Lidar system architecture.
  • FIG. 5A is a schematic flowchart of a method for calculating reflectance of a target provided by an embodiment of the present application.
  • the method can be applied to the lidar described in FIG. 4, wherein the lidar 20 can be used for Support and execute steps S501 to S503 of the method flow shown in FIG. 5A.
  • the method may include the following steps S501-S503.
  • Step S501 Extract n-part echo signals from the echo signals reflected by the target object received by the receiving end.
  • the reflectance calculation device may extract n parts of the echo signal from the echo signal reflected by the target object received by the receiving end, where every two adjacent parts of the echo signal of the n parts of the echo signal reach the The time interval of the receiving end is greater than the preset first time interval, and n is a positive integer greater than or equal to 1.
  • the echo signal received by the receiving end is the signal of the target object (the target object can be a target object or multiple objects in the target area) after receiving the transmitted signal transmitted by the transmitting end to the surface of the object, the transmitted signal is reflected back to the receiving end.
  • the reflectance calculation device is a reflectance calculation device of the target object, for example, it may be the lidar 20 in FIG. 4, or a certain part of the lidar 20.
  • the time and angle of incidence of the transmitted signal on the target will be different, which will cause the receiving end to be different.
  • the time to receive the echo reflected from the surface of the target is different (that is, the time delay of different echo signals is different), and the distance that the echo signal travels when reaching the receiving end is also different, so the return used in the reflectivity calculation
  • the wave signal intensity information is easily affected by factors such as the angle of incidence on the target and the geometric shape of the target.
  • the reflectivity calculation device can extract n parts from the echo signal reflected by the target object received at the receiving end Echo signal, and then calculate the reflectivity of the target.
  • the n-part echo signal extracted from the echo signal reflected by the target object received by the receiving end may be the echo signal that meets the conditions (that is, different targets or different parts of the target objects are separated from each other).
  • the sub-echo signals reflected back to the receiving end are all extracted into a total of n parts, or n parts of all sub-echo signals that meet the conditions can be selectively extracted. For example: in order to calculate the reflectivity simply and quickly, you can select the three sub-echo signals with the strongest signal strength from the extracted five sub-echo signals to represent all the signals received by the receiving end.
  • a sub-echo signal can represent an object, or a certain part of an object. For example: if the receiving end receives any two echoes reflected from the target at similar times, such as within the preset first time interval, and the signal strength of the echoes is similar, then the two echoes can be considered It can be the same part of the same target that reflects the echo signal back to the receiving end, so according to the time when the receiving end receives the echo, the time interval between each two adjacent echoes is greater than the preset first time interval, and the signal When the intensity difference is large, the above two echoes are considered to belong to different sub-echo signals.
  • the embodiment of the present application actually uses a method similar to calculus to bring the response corresponding to the pulse (that is, the echo in each sub-echo signal) into the radar equation.
  • the embodiments of the present application can be applied to the scene of vehicle-mounted radar with high timeliness requirements, so as to distinguish the reflectivity of objects around the vehicle in real time, monitor the objects around the vehicle, help the driver judge the road conditions around the vehicle, and ensure that the driver Drive normally, etc.
  • the type of unidentified targets can be determined by calculating the reflectivity of the moving targets.
  • the road sign graphics can be recognized by calculating the reflectivity of different colors on the road sign.
  • the reflectance calculation method in the embodiment of the present application can also be applied to the scene of aerial recognition.
  • the lidar recognizes the aerial unidentified flying object
  • the reflectance of the flying object in the target airspace can be determined to realize the identification of the material type of the flying object.
  • the reflectivity calculation method in the present application can be applied to identify the reflectivity of irregularly shaped objects.
  • the signal strength of each of the n-part echo signals is greater than the signal strength threshold.
  • the signal strength threshold can be set to the signal strength corresponding to the false alarm probability of one thousandth.
  • the false alarm probability refers to the process of lidar detection
  • the threshold detection method due to the ubiquitous existence and fluctuation of noise, it will increase the probability that there is no target object but it is judged by the lidar as a target object. Therefore, the signal strength of each sub-echo signal is greater than the signal strength threshold, which can effectively reduce the influence of other interference on the calculation of the reflectance of the target, and improve the accuracy of calculating the reflectance of the object.
  • the reflectance calculation device can convert the echo signal from a time domain signal to an impulse response of a frequency domain signal before extracting the n-component echo signal, and the impulse response can be convolved with the transmitted signal. Then the reflected echo signal is obtained. Therefore, the impulse response can intuitively show the signal strength of the transmitted signal reflected back at a certain moment.
  • the extracting n component echo signals from the echo signals reflected by the target object received by the receiving end includes: determining z impulse response sets according to the m impulse responses, where each impulse response The time interval between any two adjacent impulse responses among the multiple impulse responses included in the shock response set is within a preset second time interval, and any two impulse responses in the z impulse response sets The intersection between the sets is an empty set, z is a positive integer greater than or equal to n, and m is a positive integer greater than or equal to z; the impulse response in each impulse response set of the z impulse response sets is removed After the impulse response whose value is less than the response threshold, n impulse response sets are obtained, and the n impulse response sets correspond to the n component echo signals one-to-one, and include the impulse corresponding to the n component echo signals.
  • Irritated response Determine n impulse response sets from the m impulse responses. Each impulse response set in the n impulse response sets corresponds to a subset of the echo signals of the n elements, and n impulse responses Each impulse response set in the response set includes one or more impulse responses whose impulse response values are greater than or equal to the response threshold, and the one or more impulse responses are adjacent to it in m impulse responses.
  • the time interval between at least one impulse response is less than the preset second time interval, where the preset second time interval is less than the preset first time interval, and the preset second time interval may be a certain ratio of the pulse width or Other adaptive intervals or fixed intervals.
  • the impulse response value refers to the magnitude relationship between the absolute amplitude value of the impulse response and the response threshold value.
  • the impulse response value refers to the amplitude value of the impulse response
  • the impulse response of each sub-echo is similar to the singular function (Sinc) distribution, and includes the positive Negative amplitude. That is, the impulse response value of the impulse response may be a negative value.
  • the impulse response value is negative, the absolute value of the impulse response value is greater than or equal to the response threshold.
  • the response of the system can be divided into the sum of the impulse response, as shown in the following formula:
  • the received echo signals in the presence of noise and noise are expressed as:
  • S r (t) is the received echo signal
  • s(t) is the transmitted signal
  • M is the response number of the target object
  • ⁇ i is the scattering characteristic of the target object
  • ⁇ i is the signal at the transmitting end and receiving
  • n(t) is noise.
  • the impact of impulse response on system response is delay and amplitude change. It can be concluded that the impulse response amplitude ⁇ i at a certain fixed delay ⁇ i is equal to the ratio of the received signal to the peak power of the transmitted signal P Ri /P Ti of this part of the signal with the delay ⁇ i .
  • FIG. 5B is a schematic diagram of determining n impulse response sets from m impulse responses according to an embodiment of the present application.
  • FIG. 5C is a waveform diagram of an echo signal provided by an embodiment of the present application
  • FIG. 5D is a schematic diagram of an impulse response corresponding to the echo signal provided by an embodiment of the present application.
  • the reflectance calculation device in the embodiment of the present application can accurately determine the echo from the same target or the same part of the target from multiple targets or targets with irregular geometric shapes, thereby avoiding In the subsequent calculation of the reflectivity, the target geometry, or the reflectivity of different targets are affected, which improves the calculation accuracy of the reflectivity.
  • This method adopts the target response estimation method, which effectively solves the ambiguity caused by the target shape and incident angle in the reflectance calculation, and can be used in radars with high real-time requirements.
  • a certain amplitude threshold (such as false alarm threshold or other thresholds) needs to be met to ensure the extracted sub-echo signals Corresponding to the real target rather than other interference.
  • the output signal-to-noise ratio does not decrease proportionally with the input signal-to-noise ratio, it deteriorates sharply, that is, when the input signal-to-noise ratio of the envelope detector decreases to a certain value, the output signal-to-noise ratio of the detector appears sharply
  • One phenomenon of decline is the threshold effect, and the input signal-to-noise ratio at which the threshold effect begins to appear is called the threshold value.
  • the reflectance calculation device extracts n component echo signals from the echo signals reflected by the target object received at the receiving end, which may include: determining k signal sets according to the echo signals, wherein each signal set includes The time interval for every two adjacent echoes in the plurality of echoes to reach the receiving end is within a preset third time interval, and the intersection between any two signal sets in the k signal sets is an empty set, k is a positive integer greater than or equal to n; determine the amplitude threshold of all echoes in each signal set of the k signal sets; remove all amplitude thresholds in each signal set of the k signal sets to be less than the preset amplitude After the echo of the threshold threshold, n signal sets are obtained, and the n signal sets correspond to the n component echo signals in a one-to-one correspondence.
  • Each of the n signal sets determined from the k signal sets corresponds to one of the n sub-echo signals
  • each of the n signal sets includes one or more Echoes whose amplitude thresholds are all greater than the preset amplitude threshold threshold
  • the time interval between the one or more echoes and at least one adjacent echo when they arrive at the receiving end is less than the preset third time interval
  • the sampling interval is determined can be a certain ratio of pulse width or other adaptive interval or fixed interval. It should be noted that the preset third time interval and the preset first time interval are essentially one thing, both of which are used to distinguish the echoes of two different objects or different parts of the same object (ie, reflection points).
  • the preset third time interval may also be the time interval between echoes reflected by two reflection points on the target and whose distance is greater than or equal to the preset distance threshold to reach the receiving end.
  • the preset third time interval may be less than or equal to the preset distance threshold.
  • the first time interval is greater than the preset second time interval, and the sub-echo signal includes multiple echoes.
  • the sub-echo signal includes multiple echoes.
  • two of the echo intervals are within the preset third time interval, they are considered to belong to one sub-echo. If the echo interval is outside the preset third time interval, it is considered to belong to two sub-echoes respectively.
  • the preset third time interval can actually be set to be smaller than the preset first time interval, so as to eliminate signals with relatively large time intervals in the same sub-echo signal, that is, those with a slightly longer distance between the corresponding targets. Echo signal to achieve the purpose of accurately calculating the reflectivity of the target object.
  • the embodiment of the present application extracts the sub-echo signals that meet the amplitude threshold in the signal set, and can more accurately determine the signal from multiple targets in the target area or targets with irregular geometric shapes. The echo of the real target object, thereby avoiding the influence of factors such as the interference target object in the subsequent calculation process of the reflectivity, and improving the calculation accuracy of the reflectivity.
  • the reflectance calculation device extracting n parts of the echo signal from the echo signal reflected by the target object received by the receiving end may include: within a certain sampling interval (for example, in terms of time range) , It can be a certain ratio of the pulse width or other adaptive interval or a fixed interval as the sampling interval), the response estimation is performed on the echo signal reflected by the target object received from the receiving end, and the impulse response corresponding to the echo signal is obtained h(n); After determining all the inflection points of h(n), extract the largest n inflection points that meet the distance interval ⁇ (which can be determined according to the speed of light and time); intercept all the inflection point accessories that meet the requirements less than a certain interval (for example: two Times the pulse width of the transmitted signal) of all impulse responses.
  • a certain sampling interval for example, in terms of time range
  • ⁇ which can be determined according to the speed of light and time
  • intercept all the inflection point accessories that meet the requirements less than a certain interval for example: two Times the pulse width
  • the preset first time interval is two reflection points (the two reflection points may be two reflection points on different objects, and the distance on the target object is greater than or equal to the preset distance threshold). It can be different reflection points on the same object)
  • the time interval for the echo signal reflected by the echo signal to reach the receiving end which is equivalent to the pulse width of the echo signal, wherein the preset distance threshold can be in the range of 0.1m-1m,
  • the preset first time interval may be calculated by the ratio of the preset distance threshold to the speed of light.
  • Step S502 Calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal.
  • the method of the reflectance calculation device using the system response to calculate the reflectance is mainly to use the radar equation to perform inversion, and then use the inversion equation to calculate the sub-reflection of each sub-echo signal in the n-component echo signal. rate.
  • the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal can be substituted into the sub-reflectivity calculation formula, and the sub-echo signal of each sub-echo signal in the n-component echo signal can be calculated. Reflectivity.
  • the reflectivity calculation device calculates the sub-reflectivity of each sub-echo signal in the n-component echo signal, it also needs to determine each sub-echo in the n-component echo signal.
  • the impulse response values of all the corresponding impulse responses in the signal; wherein calculating the sub-reflectivity of each sub-echo signal in the n-component echo signal includes: according to each sub-echo signal in the n-component echo signal The impulse response values of all impulse responses in the wave signal are calculated, and the sub-reflectivity of each sub-echo signal in the n-echo signal is calculated.
  • the impulse response corresponding to the sub-echo signal can intuitively show the signal strength of the transmitted signal reflected back to the target at a certain moment, and the different delays of the impulse response represent the distance between the target and the receiving end.
  • the number of impulse responses corresponding to the sub-echo signals also represents the distribution of the reflected signal energy. Therefore, the method of calculating the reflectivity by using the impulse response of the target can be simple and accurate in the real-time processing system. Calculate the reflectivity of the object.
  • the reflectance calculation device calculates the sub-reflectivity of each sub-echo signal in the n-component echo signal according to the impulse response values of all the impulse responses in each sub-echo signal of the n-component echo signal, Including: Determine the first ratio according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, and the effective receiving area of the receiving end; the impulse response of all the impulse responses in each sub-echo signal in the n-echo signal The response value and the first ratio are respectively multiplied and then accumulated to obtain the sub-reflectivity of each sub-echo signal in the n-echo signal.
  • the first ratio is determined according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, the effective receiving area of the receiving end, etc., because the first ratio can represent the reflected echo signal in the atmosphere and the receiving end Therefore, the first ratio is multiplied by the impulse response value representing the ratio of the received signal to the transmitted signal, and then the sub-reflectivity of each sub-echo signal in the n-part echo signal obtained by calculation can be accumulated. More precise, where the impulse response value is the amplitude value of the impulse response.
  • This method of calculating reflectivity using the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, the effective receiving area of the receiving end, and the impulse response of the target object can be used to calculate the object simply and accurately in the real-time processing system of real life. ⁇ Reflectivity.
  • the reflectivity calculation device calculates the sub-reflectivity of each sub-echo signal in the n-component echo signal according to the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal, including : According to the impulse response values of all the impulse responses in each sub-echo signal in the n-molecular echo signal, calculate the sub-reflectivity of each sub-echo signal in the n-molecular echo signal through the sub-reflectivity calculation formula, where ,
  • the calculation formula of sub-reflectance can be: Where ⁇ i is the sub-reflectivity of the i-th component echo signal in the n-component echo signal, ⁇ a is the single-pass transmittance of the laser in the atmosphere, ⁇ r is the efficiency of the receiving optical system, and A r is the The effective receiving area of the receiving end, ⁇ is the angle between the optical axis of the transmitting optical system of the transmitting end and the target normal ON, and R ij is the target
  • the impulse response value h ij refers to the amplitude value of the impulse response.
  • R ij can be based on the speed of light c and the time interval between the time when the transmitting end signal is sent and the time when the echo signal arrives at the receiving end. , The distance between the target corresponding to the j-th impulse response in the i-th component’s echo signal and the receiving end is calculated.
  • the reflectivity calculation formula is the reflectivity calculation formula inversed by the radar equation, which is implemented in this application.
  • the amplitude value of the impulse response regarded as an impulse response is used to represent the signal strength reflected back by the target at a certain moment of the transmitted signal. Therefore, it can be based on the impulse response corresponding to the jth impulse response in the i-th component echo signal.
  • the echo signal of the i-th component obtained by the shock response value corresponds to the reflectance information of the target, which reduces the difficulty of calculating the reflectance.
  • the sub-reflectance calculation formula is used to calculate the sub-reflectivity of the n-member echo signal through the amplitude value, where, It can be regarded as the amplitude f j of the j-th sub-echo signal of the n-echo signal that satisfies the above conditions. It is understandable that when calculating the reflectivity in this application, the obtained impulse response value refers to the magnitude of the impulse response.
  • Step S503 accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target object.
  • the reflectance calculation device accumulates the n-component reflectance to obtain the reflectance of the target object.
  • the reflected energy of the object can be regarded as a fixed part, and then the whole reflected energy is divided into n small parts and then accumulated, and a complete part of energy can still be obtained. Therefore, the reflectance calculation device
  • the n-part echo signal can be extracted from the echo signal reflected by the target object received by the receiving end, and the sub-reflectivity of the n-part echo signal can be accumulated to obtain the reflectance of the object or target in the target area.
  • the reflectance can be further corrected or calibrated again to obtain more accurate reflectance information. It can be understood that the reflectance obtained by this method is the average reflectance of the object in the target area or the target object.
  • FIG. 5E is a comparison table of the calculation results of a target reflectivity calculation method provided by an embodiment of the present application and a reflectance calculation method based on intensity inversion in the second solution.
  • the embodiment of the present application From the perspective of system response, the process of transmitting the signal is regarded as a system, the overall response of the system is used to gradually decouple, and then the inversion method is used to estimate the reflectivity.
  • the sub-reflectivity of each sub-echo signal in the n-component echo signal is calculated according to the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal and the sub-reflectivity calculation formula,
  • Using the target response estimation method can limit the error of the reflectance estimation to a relatively small range, and effectively solve the problem of the ambiguity of the reflectance estimation caused by the shape of the target, the angle of incidence, etc., compared to the single peak point estimation or the peak superposition method.
  • Figure 5E shows the mean value and standard deviation of the above two reflectance estimation methods.
  • the calculated reflectance in the embodiment of this application is 0.0961 and the standard deviation is 0.000417, which is compared with the true reflectance.
  • the maximum deviation of is less than 7%; and the above-mentioned scheme 2 provides a reflectance calculation method based on intensity inversion.
  • the calculated reflectance is 0.0726 at a single peak point, and the standard deviation is 0.0093, which is the smallest deviation compared to the true reflectance. If it is still greater than 15%, it can be seen that the method for estimating the target response provided by the embodiment of the present application has obvious advantages. It should be noted that the above result is only a schematic table of the effect in a certain scene, and does not represent the situation of all scenes.
  • the model is simple and does not need to be calibrated, which is better for real-time In the processing system, the reflectivity of the object is simply and accurately calculated.
  • the geometric shape of the target object is irregular (for example, the target object has more Surfaces with different angles), which may result in different incident angles when the transmitted signal is irradiated on different surfaces of the object, resulting in different reflectivity calculation results of the target object; moreover, if the target object is multiple objects in the target area, due to The locations of multiple target objects may be very close to the receiving end, so multiple target objects may also be regarded as an object with an irregular geometric shape.
  • the reflectance calculation device can receive at the receiving end After extracting the n-component echo signal from the target object’s echo signal, calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal, and finally accumulate the n-component reflectivity to obtain the object or target in the target area ⁇ Reflectivity.
  • the same part of the same target object has the same or similar material, angle of incidence, and distance from the receiving end, the signals reflected by this part back to the receiving end are all similar signals with similar time intervals.
  • the target has two parts with different distances, even if the two parts have the same material and shape, as long as the distances from the receiving end are different, the time to reach the receiving end will also be different, and then the two parts The time interval of the signal reflected back to the receiving end is greater than the preset first time interval. Therefore, the two parts cannot be considered to be the same part of the same target. Therefore, if the receiving end receives any two echoes reflected back from the target within the preset first time interval, it can be considered that the two echoes can belong to the same part of the same target reflected back to the receiving end.
  • Sub-echo signals where the preset first time interval is the time interval between the echo signals reflected by the two reflection points on the target and the distance greater than or equal to the preset distance threshold reaching the receiving end, and the target can be a target object or Multiple objects in the target area. Further, the embodiment of the present application can extract n sub-echo signals from the echo signal reflected by the target object received by the receiving end according to the above-mentioned rules. It can be understood that a sub-echo signal represents an object or a certain part of an object.
  • the process of transmitting the signal is regarded as a system, and the overall response of the system is gradually decoupled, and then the method of inversion is performed to calculate the reflectivity, which is different from the existing technology to calculate the reflection.
  • the error of reflectance estimation can be limited to a relatively small range, which effectively solves the problem of ambiguity in reflectance estimation caused by the shape of the target and the angle of incidence.
  • the n-part echo signal extracted from the echo signal reflected by the target object received by the receiving end can be extracted from the echo signal that meets the conditions, and divided into The n-part echo signal can also be selected from all the sub-echo signals that meet the conditions, where n parts of the signal are selectively extracted as the sub-echo signal, and n is a positive integer greater than or equal to 1. Therefore, the echo signal is extracted from the n-part echo signal, the sub-reflectivity of the n-part echo signal is calculated and then accumulated to obtain the reflectivity of the entire target, which avoids the calculation of the incident angle and the geometric shape of the target due to the transmitted signal.
  • the influence of the reflectance of the target object, and the method is simple, and can be applied in a real-time processing system to calculate the reflectance of the object simply and accurately, which improves the accuracy and efficiency of the calculation of the reflectance.
  • FIG. 6 is a schematic flowchart of another method for calculating reflectance of a target provided by an embodiment of the present application. This method can be applied to the lidar described in FIG. 4, wherein the lidar 20 can be used It supports and executes steps S601 to S605 of the method flow shown in FIG. 6.
  • Step S601 Perform response estimation on the echo signal by the least square method or the least mean square error method to obtain m impulse responses corresponding to the echo signal.
  • the response estimation of the target object can be used to estimate the reflected signal by the least square method, the least mean square error and other methods. That is, the reflectance calculation device can estimate the response of the echo signal by the least square method or the least mean square error method, and obtain m impulse responses corresponding to the echo signal. The m impulse responses can be compared with the transmitted signal. After the product, the echo signal reflected back to the receiving end is obtained.
  • the echo that meets a certain distance interval ⁇ or the echo that meets the time interval of reaching the receiving end are different echoes, and a certain condition is selected near each echo (for example, the condition may include but The impulse response is not limited to a certain duration, a certain sampling point, a certain correlation coefficient threshold, etc.) for subsequent decoupling.
  • Step S602 Determine z impulse response sets according to the m impulse responses; after removing the impulse responses whose impulse response value is less than the response threshold in each impulse response set of the z impulse response sets, n impulse responses are obtained Response collection.
  • the reflectance calculation device may determine z impulse response sets according to the m impulse responses, where any two adjacent impulse responses among the multiple impulse responses included in each impulse response set The time interval between is within the preset second time interval, the intersection between any two impulse response sets in the z impulse response sets is an empty set, z is a positive integer greater than or equal to n, and m Is a positive integer greater than or equal to z; after removing the impulse responses whose impulse response value is less than the response threshold in each impulse response set of the z impulse response sets, n impulse response sets are obtained.
  • One set of impulse responses corresponds to the n-part echo signals in a one-to-one correspondence, and includes impulse responses corresponding to the n-part echo signals.
  • Step S603 According to the m impulse responses, calculate the impulse response values of all the corresponding impulse responses in each of the n component echo signals.
  • the reflectivity calculation device can convert the echo signal from a time domain signal to an impulse response of a frequency domain signal.
  • the impulse response can be convolved with the transmitted signal to be reflected back to the receiver. Therefore, the impulse response corresponding to the echo signal can intuitively show the signal strength reflected by the target object at a certain moment, that is, the impulse response of one or more impulse responses corresponding to the sub-echo signal.
  • the shock response value can represent the signal strength at which the target represented by the sub-echo signal reflects the transmitted signal back to the receiving end at a certain moment.
  • the reflectivity of an object is the ratio of the reflected radiant energy projected on the object to the total radiant energy projected on the object
  • one or more corresponding sub-echo signals can be directly used in the real-time processing system.
  • the impulse response value of the impulse response calculates the sub-reflectivity of the corresponding sub-echo signal, and then determines the reflectivity of the entire target.
  • This simple and accurate calculation method can effectively solve the target shape and incidence in the reflectivity calculation.
  • the blur problem caused by the angle not only improves the calculation accuracy and efficiency of the reflectance, but also can more intuitively distinguish the difference of the reflectance of different objects. For example, an object with a larger impulse response value has a greater reflectivity.
  • the impulse response value in the embodiment of the present application refers to the magnitude value of the impulse response.
  • the impulse response value of all the impulse responses in each sub-echo signal in the n-part echo signal removes one or more of the receiving end, the channel, and the transmitting end
  • the magnitude of the impulse response after the influencing factors, the influencing factors including one or more of loss, filtering, and attenuation. Because after the echo signal is received at the receiving end, it needs to be converted from analog to digital by the detector, and then in the process of processing the converted signal through the processor, on the one hand, it will be affected by the transmitting end, receiving end or detector in the processing process.
  • the loss, filtering or attenuation of other devices such as receivers, avalanche photodiodes, transimpedance amplifiers, low-pass filters, analog-to-digital converters, etc.
  • the efficiency and loss of the receiving end will also affect the signal To change. Therefore, before calculating the sub-reflectance, it is necessary to decouple these influencing factors, and then substitute the amplitude value of the impulse response after removing the influence into the formula calculation to obtain a more accurate reflectance result.
  • the decoupling methods include but are not limited to actual calibration, device and system modeling, or a combination of the two, and so on.
  • the system's response includes the transmitter, channel, target and receiver during the transmission of the signal. Wait for at least four parts of the response.
  • the response estimated based on the transmitted and received signals contains the above parts. Therefore, it is necessary to decouple the parts that are not related to the response of the target to obtain the echo signal only related to the target, which makes the calculation of the target's reflectivity better. accurate.
  • the influencing factors of the receiving end can be decoupled during the reflectivity calculation process.
  • the echo signal When the echo signal is received from the detector to the signal processing end, on the one hand, it will be affected by the loss and filtering of APD, TIA, ADC and other devices. On the other hand, the receiver efficiency and insertion loss will also bring changes to the signal. Therefore, in the defuzzification of the response, these influencing factors need to be decoupled.
  • Decoupling methods include but are not limited to actual calibration, device and system modeling, or a combination of the two. In a possible implementation, the actual calibration method steps are as follows: In the actual system, signals of different waveforms are used at the receiving end as the signals that may be received by the receiving end.
  • the different waveforms here include, but are not limited to, different pulse widths, Different amplitudes, different envelope shapes, etc.
  • the waveforms output by the signal processing terminal are collected and corresponded to the input signals one-to-one.
  • the input and output signals of the receiving end system can be obtained, so that the response of the receiving end to different signals can be estimated, and the corresponding model or look-up table can be established.
  • the signal received through LiDAR can be used to obtain the influence of the receiver on the signal through the established receiver system model or look-up table, and then this influence can be removed by methods including but not limited to deconvolution. .
  • the steps of device and system modeling are as follows: In the receiving end system, model devices such as APD, TIA, ADC, etc., and separately analyze the influence or effect of each device on signals using different waveforms. Response analysis, the different waveforms here include, but are not limited to, different pulse widths, different amplitudes, and different envelope shapes.
  • the response of the entire system at the receiving end is obtained according to the accumulation of the influence or response of the discrete device on the signal.
  • the signal received through LiDAR can be used to obtain the influence of the receiver on the signal through the established receiver system model or look-up table, and then this influence can be removed by methods including but not limited to deconvolution.
  • the channel influencing factors can be decoupled during the reflectivity calculation process.
  • the influence of atmospheric attenuation, geometric loss, etc. affects the amplitude-frequency response of the system to a certain extent.
  • the influencing factor can be deblurred.
  • Methods of decoupling channel effects include, but are not limited to, system modeling, actual calibration, or a combination of the two. The method of decoupling the influence of the channel is basically the same as the method of decoupling the receiving end described above.
  • the decoupling of the influence of the channel is in the system modeling method, because each part of the atmospheric channel affects (ie: multiple types of loss during transmission) ) Is a common effect on the signal, rather than the discrete effect in the above-mentioned method of decoupling the receiving end. Therefore, the method of system modeling is to take the entire channel as a whole while considering the effects of loss and atmospheric scattering to model and decouple the effects. Afterwards, in real-time processing, the signal received through LiDAR can be used to obtain the influence of the receiving end on the signal through the established channel loss model or look-up table, and then this influence can also be carried out by methods including but not limited to deconvolution. Remove.
  • the influencing factors of the transmitting end can be decoupled during the reflectivity calculation process.
  • the waveform and amplitude of the transmitted signal can be obtained more accurately through system design, there will be different differences in the actual LiDAR system, including but not limited to amplifiers, scanners, and optical devices. Therefore, at the transmitting end, these effects also need to be decoupled.
  • Methods include but are not limited to system modeling, actual calibration, or a combination of the two.
  • the method for estimating and decoupling the response of this part of the system is basically the same as the method for decoupling the receiving end described above. In the modeling method of the system and the device, different transmitting end devices are also affected separately.
  • the difference is that in the system calibration of the decoupling of the influencing factors of the transmitter, if it is not possible to receive all the transmitted signals directly from the transmitter, it is necessary to pass a certain distance channel to receive all the transmitted signals.
  • the geometric loss can be calculated by a simple modeling method. After the channel influence is reduced to a minimum, decouple all the influence factors that receive the transmitted signal.
  • This method adopts the response estimation method, which can accurately estimate the target reflectivity information corresponding to a single echo after decoupling the unrelated factors of the system, and can be used in vehicle-mounted lidars with high real-time requirements.
  • the reflectivity calculation process decouples the three influencing factors of the transmitter, channel, and receiver. Therefore, the echo signal calculated by the reflectivity calculation device only contains the influence of the target, which can be more effective. Accurately calculate the reflectivity of the target object.
  • Step S604 Calculate the sub-reflectivity of each sub-echo signal in the n-component echo signal according to the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal.
  • Step S605 accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target object.
  • step S604 for the related description of step S604 to step S605, reference may be made to the related description of step S502 to step S503 in FIG. 5A, which will not be repeated here.
  • the impulse response corresponding to the echo signal can intuitively represent the signal strength of the transmitted signal reflected by the target at a certain moment, that is, the impulse response of one or more impulse responses corresponding to the sub-echo signal.
  • the shock response value can represent the signal strength of the target represented by the sub-echo signal reflecting the transmitted signal back to the receiving end at a certain moment. Therefore, before extracting the n-component echo signal, the echo signal can be converted from the time domain signal Transform into the impulse response of the frequency domain signal. Also, because the reflectivity of an object is the ratio of the reflected radiant energy projected on the object to the total radiant energy projected on the object, one or more impulses corresponding to the sub-echo signal can be used in the real-time processing system.
  • This calculation method of using the impulse response inversion to obtain the reflectivity can effectively solve the problem in the calculation of the reflectivity.
  • the geometric shape of the target and the incident angle of the transmitted signal cause the problem of ambiguity in the calculation of reflectivity.
  • the embodiment of the present application not only improves the calculation accuracy and efficiency of the reflectivity, but also can use the different impulse response values of the sub-echo signals, Intuitively distinguish the reflectivity of different objects. For example: an object with a larger impulse response value has a greater reflectivity.
  • the implementation of this application can not only be applied to lidar, but also can be applied to radar systems such as: "line sending and receiving", “surface sending and receiving”, “point sending and receiving” and other radar systems.
  • the parts that cause deviations in the reflectance calculation include transmitter and receiver components, channel effects, and target characteristics.
  • the transmitter and receiver components can be decoupled from influencing factors through methods such as actual calibration or device modeling, and channel effects can also be removed through methods such as modeling.
  • target characteristics such as shape, material, and incident angle changes caused by its shape will cause very large deviations in the calculation of echo intensity and reflectivity, and real-time deblurring of this effect is a difficult point.
  • the process of transmitting the signal is regarded as a system, and the overall response of the system is used to gradually decouple the influencing factors, and then the reflectivity calculation is performed by the method of radar equation inversion.
  • the method of peak point estimation or peak superposition has been significantly improved.
  • the reflectance calculation method in this application can be applied to the scenario of calculating the reflectance of lidar. It is also used to determine the number, material, type, etc. of the objects in the target area through the calculated reflectivity in a real-time monitoring scene. For example: the real-time vehicle-mounted system recognizes traffic signs, pedestrians, and obstacles on the roadside through the monitoring of reflectivity. Furthermore, it can also be applied to fields such as intelligent transportation, autonomous driving, atmospheric environment monitoring, geographic surveying and mapping, and UAV reconnaissance. More broadly, any scene where the reflectance needs to be calculated can be applied to the solution provided in this application. This method can be applied to lidar systems such as "line sending and receiving", “face sending and receiving", and "point sending and receiving”.
  • FIG. 7 is a schematic structural diagram of an apparatus for calculating reflectance of a target object provided by an embodiment of the present application.
  • the apparatus 10 for calculating reflectance of the target object may include an extraction unit 701, a sub-reflectance unit 702, and a reflectance
  • the unit 703 may further include: a response estimation unit 704, a first determination unit 705, and a second determination unit 706.
  • the detailed description of each unit is as follows:
  • the extracting unit 701 is configured to extract n-part echo signals from the echo signal reflected by the target object received by the receiving end, where every two adjacent parts of the echo signal in the n-part echo signals arrive at the receiving end
  • the time interval of the terminal is greater than the preset first time interval, and n is a positive integer greater than or equal to 1.
  • the sub-reflectivity unit 702 is used to calculate the sub-reflectivity of each sub-echo signal in the n-echo signal.
  • the reflectivity unit 703 is configured to accumulate the sub-reflectivity of the n-component echo signal to obtain the reflectivity of the target object.
  • the signal strength of each of the n-part echo signals is greater than the signal strength threshold.
  • the device further includes: a response estimation unit 704, which is used for extracting the n-part echo signal from the echo signal reflected by the target object received from the receiving end by using the least square method or The minimum mean square error method estimates the response of the echo signal to obtain m impulse responses corresponding to the echo signal, where m is a positive integer greater than or equal to 1; After extracting the n-component echo signal from the echo signal reflected by the received target, according to the m impulse responses, calculate the impulse response of one or more impulse responses corresponding to each component of the n-component echo signal.
  • a response estimation unit 704 which is used for extracting the n-part echo signal from the echo signal reflected by the target object received from the receiving end by using the least square method or The minimum mean square error method estimates the response of the echo signal to obtain m impulse responses corresponding to the echo signal, where m is a positive integer greater than or equal to 1; After extracting the n-component echo signal from the echo signal reflected by the received target, according to the
  • Shock response value; calculating the sub-reflectivity of each sub-echo signal in the n-part echo signal includes: calculating the corresponding sub-echo according to the impulse response value of one or more impulse responses corresponding to each sub-echo signal The sub-reflectivity of the signal.
  • the extraction unit 701 is specifically configured to: determine z impulse response sets according to the m impulse responses, wherein each impulse response set includes multiple impulse responses
  • the time interval between any two adjacent impulse responses in is within a preset second time interval, the intersection between any two impulse response sets in the z impulse response sets is an empty set, and
  • the preset second time interval is a preset time interval less than the preset first time interval, z is a positive integer greater than or equal to n, and m is a positive integer greater than or equal to z;
  • the z impulse response sets are removed After the impulse response of each impulse response set in which the impulse response value is less than the response threshold, n impulse response sets are obtained, and the n impulse response sets correspond to the n component echo signals one-to-one, and Including the impulse response corresponding to the n-component echo signal.
  • the extracting unit 701 is specifically configured to: determine k signal sets according to the echo signals, wherein each of the multiple echoes included in each signal set is adjacent to each other.
  • the time interval for the echo to reach the receiving end is within the preset third time interval, the intersection between any two signal sets in the k signal sets is an empty set, and k is a positive integer greater than or equal to n;
  • the n signal sets have a one-to-one correspondence with the n component echo signals.
  • the device further includes: a second determining unit 706, configured to determine the sub-reflectivity of each sub-echo signal in the n sub-echo signals before the calculation The impulse response values of all the corresponding impulse responses in each sub-echo signal in the n-component echo signal; the sub-reflectivity unit 702 is specifically configured to: according to each sub-echo signal in the n-component echo signal Calculate the sub-reflectivity of each sub-echo signal in the above-mentioned n-component echo signal with the impulse response values of all the impulse responses in the above-mentioned.
  • the aforementioned sub-reflectance unit 702 is specifically used to determine the first ratio according to the single-pass transmittance of the laser in the atmosphere, the efficiency of the receiving optical system, and the effective receiving area of the receiving end;
  • the impulse response values of all the impulse responses in each sub-echo signal in the wave signal are respectively multiplied by the first ratio and then accumulated to obtain the sub-reflectivity of each sub-echo signal in the n-echo signal.
  • the above-mentioned sub-reflectance unit 702 is specifically used to calculate the sub-reflectance calculation formula according to the impulse response values of all the impulse responses in each sub-echo signal in the n-component echo signal
  • the sub-reflectivity of each sub-echo signal in the n-member echo signal where the sub-reflectivity calculation formula is: Where ⁇ i is the sub-reflectivity of the i-th component echo signal in the n-component echo signal, ⁇ a is the single-pass transmittance of the laser in the atmosphere, ⁇ r is the efficiency of the receiving optical system, and A r is the The effective receiving area of the receiving end, ⁇ is the angle between the optical axis of the transmitting optical system of the transmitting end and the target normal ON, and R ij is the target corresponding to the jth impulse response in the i-th component echo signal and the receiving The distance between the ends, Is the impulse response value corresponding to the jth impulse response in the i
  • the impulse response value of all the impulse responses in each sub-echo signal in the n-part echo signal removes one or more of the receiving end, the channel, and the transmitting end
  • the above-mentioned preset first time interval is the time interval between two echo signals respectively reflected by two reflection points on the target and whose distance is greater than or equal to the preset distance threshold to reach the receiving end.
  • each functional unit in the device 10 for calculating the reflectance of the target described in the embodiment of the present application can be referred to the related description of the method embodiment described in the above-mentioned FIG. 5A-6, which will not be omitted here. Go into details.
  • FIG. 8 is a schematic structural diagram of another target reflectance calculation device provided by an embodiment of the present application.
  • the device 20 includes at least one processor 201, at least one memory 202, and at least one communication interface 203.
  • the device may also include general components such as antennas, which will not be described in detail here.
  • the processor 201 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the above program programs.
  • CPU central processing unit
  • ASIC application-specific integrated circuit
  • the communication interface 203 is used to communicate with other devices or communication networks, such as Ethernet, radio access network (RAN), core network, wireless local area networks (WLAN), etc.
  • RAN radio access network
  • WLAN wireless local area networks
  • the memory 202 can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM), or other types that can store information and instructions
  • the dynamic storage device can also be electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), CD-ROM (Compact Disc Read-Only Memory, CD-ROM) or other optical disc storage, optical disc storage (Including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or can be used to carry or store desired program codes in the form of instructions or data structures and can be used by a computer Any other media accessed, but not limited to this.
  • the memory can exist independently and is connected to the processor through a bus.
  • the memory can also be integrated with the processor.
  • the memory 202 is used to store application program codes for executing the above solutions, and the processor 201 controls the execution.
  • the processor 201 is configured to execute application program codes stored in the memory 202.
  • the code stored in the memory 202 can execute the reflectance calculation method provided in FIG. 5A, such as extracting n-part echo signals from the echo signal reflected by the target object received at the receiving end, where each phase of the n-part echo signals The time interval for the adjacent two echo signals to reach the receiving end is greater than the preset first time interval, and n is a positive integer greater than or equal to 1; calculate the subreflectivity of each of the n echo signals; divide the n components The sub-reflectivity of the echo signal is accumulated to obtain the reflectivity of the target object.
  • each functional unit in the target reflectivity calculation device 20 described in the embodiment of the present application can be referred to the relevant description of the method embodiment described in FIG. 5A to FIG. 6, which will not be omitted here. Go into details.
  • the disclosed device may be implemented in other ways.
  • the device embodiments described above are only illustrative, for example, the division of the above-mentioned units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or integrated. To another system, or some features can be ignored, or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical or other forms.
  • the units described above as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.
  • the functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the above-mentioned integrated unit can be implemented in the form of hardware or software functional unit.
  • the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium.
  • the technical solution of the present application essentially or the part that contributes to the existing technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , Including several instructions to enable a computer device (which may be a personal computer, a server or a network device, etc., specifically a processor in a computer device) to execute all or part of the steps of the above methods of the various embodiments of the present application.
  • the aforementioned storage media may include: U disk, mobile hard disk, magnetic disk, optical disk, read-only memory (Read-Only Memory, abbreviation: ROM) or Random Access Memory (Random Access Memory, abbreviation: RAM), etc.
  • U disk mobile hard disk
  • magnetic disk magnetic disk
  • optical disk read-only memory
  • Read-Only Memory abbreviation: ROM
  • Random Access Memory Random Access Memory

Abstract

一种目标物的反射率计算方法、装置及相关设备，以在实时处理系统中，简单精确的计算物体的反射率。所述方法包括：首先从接收端接收的目标物反射的回波信号中每相邻两份子回波信号到达接收端的时间间隔大于预设第一时间间隔的信号全部提取出来，分为n份子回波信号，其中，n为大于或等于1的正整数；然后计算提取出的n份子回波信号中每一份子回波信号的子反射率；最后将每一份子回波信号的子反射率累加获得目标物的反射率。

Description

一种目标物的反射率计算方法、装置及相关设备 技术领域
本申请涉及雷达领域，尤其涉及一种目标物的反射率计算方法、装置及相关设备。
背景技术
反射率是物体的固有属性之一，在现有技术中，反射率可以用于识别物体材料，例如，在车载雷达识别路标时，可以通过计算路标上的不同颜色的反射率，实现路标识别；在激光雷达识别空中不明飞行物时，可以通过确定目标空域内飞行物体的反射率，实现飞行物体的种类识别。因此，反射率的计算可以应用于智能交通、自动驾驶、大气环境监测、地理测绘、无人机侦查等领域。目前，反射率计算的方法主要有两种：(1)目标辐照特性建模法，该方法是基于双向反射分布函数(Bidirectional Reflectance Distrbtion Tunction，BRDF)等方法对目标物的反射特性进行建模后，较为精确地得到目标物在朗伯反射下反射光的能量、成分和偏振态等信息，再根据上述信息计算目标物的反射率。(2)强度信息反演法，该方法需要准确得知目标物回波的强度信息，将其带入雷达方程并对其他参数进行解耦后，得到反射率信息。与第一种方法相比，第二种方法不需要对目标物反射信息进行建模，可以通过简单的算法得到较为准确的反射率信息，可应用在实时处理系统中。
但是上述第一种方法在对目标物的反射特性进行建模时因需要得知入射角、粗糙度等信息，而且该方法所使用的模型复杂且需要一定的标定工作，往往需要通过离线计算，因此难以应用在实时处理系统中。上述第二种方法虽然可以应用于实时处理系统中，但是在进行估算时所使用的回波信号强度信息容易受到入射到目标物上的入射角、目标物几何形状等因素影响，受到影响后可能导致在该方法的计算过程中引入比较大的偏差，进而给反射率的准确计算带来困难。
因此如何在实时处理系统中，简单精确的计算物体的反射率，是亟待解决的问题。
发明内容
本申请实施例提供了一种目标物的反射率计算方法、装置及相关设备，以在实时处理系统中，简单精确的计算物体的反射率。
第一方面，本申请实施例提供了一种目标物的反射率计算方法，可包括：从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，n份子回波信号中的每相邻两份子回波信号到达接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；计算n份子回波信号中每一份子回波信号的子反射率；将n份子回波信号的子反射率累加获得目标物的反射率。
通过第一方面提供的方法，本申请实施例可以在接收端接收的目标物体的回波信号中提取出n份子回波信号后，再计算n份子回波信号中每一份子回波信号的子反射率，最后将n份子反射率累加获得目标区域内物体或者目标物的反射率。其中，因为同一个目标物体的同一部分拥有相同或相似的材质、入射角以及与接收端之间的距离，所以被该部分反射回接收端的信号强度都是相似且时间间隔相近的信号。假若，目标物有两个不同距离的 两个部位，即使该两个部位拥有相同的材质和形状，只要距离接收端之间的距离不同，则到达接收端的时间也就不同，进而该两个部位反射回接收端的信号的时间间隔大于预设第一时间间隔，因此，不能认为该两个部位是同一个目标物的同一部分。因此，若接收端接收从目标物反射回的任意两个回波的时间在预设第一时间间隔内时，则可以认为该两个回波可以属于同一个目标物的同一部分反射回接收端的子回波信号。进一步的，本申请实施例可以按照上述规则从接收端接收的目标物反射的回波信号中提取出n份子回波信号，可以理解的是，一份子回波信号代表一个物体或一个物体的某一部分，这种从系统响应的角度出发，将发射信号所经历的过程当做一个系统，利用系统的整体响应逐步去耦合，然后进行反演的方法进行反射率计算的方法，与现有技术计算反射率的方法相比，可以将反射率估计的误差限制在一个比较小的范围内，有效解决目标物形状、入射角等引起的反射率估计模糊问题。其中，还需要说明的是，从接收端接收的目标物反射的回波信号中提取出的n份子回波信号可以是在回波信号中把符合条件的子回波信号全部提取出来，分为n份子回波信号，还可以是在符合条件的全部子回波信号中选择性的提取其中的n份信号为子回波信号，n为大于或等于1的正整数。因此，将回波信号提取n份子回波信号，计算n份子回波信号的子反射率后再累加获得整个目标物反射率的方法，避免了因发射信号受到入射角、目标物几何形状对计算目标物反射率的影响，而且方法简单，可以应用在实时处理系统中，简单精确的计算物体的反射率，提高了反射率的计算精度和效率。
在一种可能实现的方式中，n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。本申请实施例在提取n份子回波信号时需要将信号强度不大于信号强度阈值的回波剔除，因为只有当回波信号强度在信号强度阈值以上时，才认为该回波信号是目标物反射回接收端的回波信号，若回波信号的强度太弱则可以认为是干扰，所以可以忽略该回波信号。例如：信号强度阈值的大小可以设置为虚警概率为千分之一时对应的信号强度，需要说明的是，在激光雷达检测物体的应用场景下，虚警概率是指在激光雷达探测的过程中，采用门限检测的方法时由于噪声的普遍存在和起伏，会提升实际不存在目标物体却被激光雷达判断为有目标物体的概率。因此，每一份子回波信号的信号强度大于信号强度阈值，可以有效的降低其他干扰对计算目标物反射率的影响，提高了计算物体反射率的精度。
在一种可能实现的方式中，上述从接收端接收的目标物反射的回波信号中提取出n份子回波信号之前，该方法还包括：通过最小二乘法或最小均方差法对回波信号进行响应估计，获得回波信号对应的m个冲激响应，m为大于或等于1的正整数；从接收端接收的目标物反射的回波信号中提取出n份子回波信号之后，还包括：根据m个冲激响应，计算n份子回波信号中每一份子回波信号对应的一个或多个冲激响应的冲激响应值；计算n份子回波信号中每一份子回波信号的子反射率包括：根据每一份子回波信号对应的一个或多个冲激响应的冲激响应值计算对应的子回波信号的子反射率。本申请实施例在提取n份子回波信号前，可以将回波信号由时域信号转变为频域信号的冲激响应，该冲激响应可以与发射信号卷积后得到反射回接收端的回波信号，因此，回波信号对应的冲激响应能够直观的表现出发射信号在某一时刻目标物反射回的信号强度，即子回波信号对应的一个或多个冲激响应的冲激响应值，可以表示在某一时刻由该子回波信号代表的目标物将发射信号反射回接收端的信号强度。又因为，物体的反射率是投射到物体上面被反射的辐射能与投射到 物体上的总辐射能之比，所以在实时处理系统中，可以直接利用子回波信号对应的一个或多个冲激响应的冲激响应值，计算对应的子回波信号的子反射率后，再进一步的确定整个目标物的反射率。其中，需要说明的是，上述每个子回波代表多个满足预设距离阈值物体中任意一个物体或者一个物体满足预设距离阈值的不同部分，子回波信号的冲激响应的时延代表了物体的形状与入射角特征，冲激响应的幅度代表了物体的反射率特征，而且该子回波对应的冲激响应的幅度之和表征了该物体的反射率强度；各个子回波冲激响应幅度的叠加表征了一次发射脉冲或发射信号到目标物体反射回来的反射率均值。综上所述，这种简单精确的计算方式，可以有效解决反射率计算中的目标物形状、入射角引起的模糊问题，在提高了反射率的计算精度和效率的同时，还可以更直观的区分出不同物体反射率的区别。
在一种可能实现的方式中，上述从接收端接收的目标物反射的回波信号中提取出n份子回波信号，包括：根据m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，预设第二时间间隔为小于预设第一时间间隔的预设时间间隔，z为大于或等于n的正整数，且m为大于或等于z的正整数；去除z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，n个冲激响应集合与n份子回波信号一一对应，且包括n份子回波信号对应的冲激响应。本申请实施例从m个冲激响应中确定出n个冲激响应集合，该n个冲激响应集合中每一个冲激响应集合都分别对应n份子回波信号中的一份子回波信号，n个冲激响应集合中每一个冲激响应集合中包括一个或多个冲激响应值均大于响应阈值的冲激响应，而且该一个或多个冲激响应在m个冲激响应中与其相邻的至少一个冲激响应之间的时间间隔小于预设第二时间间隔。需要说明的是，在判断冲激响应值与响应阈值之间的大小关系时，可以理解为冲激响应的绝对幅度值与响应阈值之间的大小关系。因此，本申请实施例准确地从多个目标物或者不规则几何形状的目标物中，确定出来自于同一个目标物或者一个目标物相同部分的回波，进而避免后续在反射率的计算过程中目标物几何形状、入射角等因素影响，提高了反射率的计算精度。
在一种可能实现的方式中，上述从接收端接收的目标物反射的回波信号中提取出n份子回波信号，包括：根据回波信号确定k个信号集合，其中，每一个信号集合中包括的多个回波中的每相邻两个回波到达接收端的时间间隔在预设第三时间间隔内，k个信号集合中任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；确定k个信号集合的每一个信号集合中所有回波的幅度门限；去除k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，n个信号集合与n份子回波信号一一对应。本申请实施例，从k个信号集合中确定出的n个信号集合中，每一个信号集合都分别对应n份子回波信号中的一份子回波信号，n个信号集合中每一个信号集合中都包括一个或多个幅度门限均大于预设幅度门限阈值的回波，而且该一个或多个回波在到达接收端时与其相邻的至少一个回波之间的时间间隔小于预设第三时间间隔，需要说明的是，当输出信噪比不是按比例随着输入信噪比下降，而是急剧恶化，就是当包络检波器的输入信噪比降低到一个特定的数值后，检波器的输出信噪比出现急剧下降的一种现象为门限效应。可以理解的是，这个幅度门限可以是激光雷达的虚警门限或其他门限。在从接收 端接收的目标物反射的回波信号中提取出n份子回波信号时，即需要满足一定幅度门限(如：虚警门限或其他门限)以保证提取出的子回波信号对应的为真实目标物而不是其它干扰。综上所述，本申请实施例通过确定信号集合中满足幅度门限的信号提取为子回波信号，可以较为准确地从目标区域内多个目标物或者不规则几何形状的目标中，确定出来自真实目标物的回波，进而避免后续在反射率的计算过程中受到干扰目标物等因素影响，提高了反射率的计算精度。
在一种可能实现的方式中，上述计算n份子回波信号中每一份子回波信号的子反射率之前，还包括：确定n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；计算n份子回波信号中每一份子回波信号的子反射率，包括：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算n份子回波信号中每一份子回波信号的子反射率。本申请实施例在计算子反射率之前，需要确定提取的n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值，然后根据该冲激响应值计算每一份子回波信号的子反射率。子回波信号对应的冲激响应能够直观的表现出发射信号在某一时刻目标物反射回的信号强度，冲激响应不同的时延代表了目标物与接收端之间距离的差别，而且子回波信号对应的冲激响应个数也可以代表反射信号能量所分配份数，即，目标物体反射回接收端的信号将分配为不同时间延迟、不同能量的若干份。因此，利用目标物的冲激响应计算反射率的方法可以在实时处理系统中，简单精确的计算物体的反射率。
在一种可能实现的方式中，上述根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算n份子回波信号中每一份子回波信号的子反射率，包括：根据激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积，确定第一比值；将n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与第一比值分别相乘后累加，获得n份子回波信号中每一份子回波信号的子反射率。在本申请实施例中，首先根据激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积等，确定第一比值，因为第一比值可以代表反射的回波信号在大气和接收端等中受到的影响，所以再将该第一比值与代表接收信号与发射信号比值的冲激响应值相乘后累加计算获得的n份子回波信号中每一份子回波信号的子反射率可以更加精确，其中，冲激响应值为冲激响应的幅度值。这种利用激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积与目标物的冲激响应计算反射率的方法可以在实际生活的实时处理系统中，简单精确的计算物体的反射率。
在一种可能实现的方式中，上述根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算n份子回波信号中每一份子回波信号的子反射率包括：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算n份子回波信号中每一份子回波信号的子反射率，其中，子反射率计算公式为：
Figure PCTCN2019105439-appb-000001
其中，ρ i为所述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为所述接收端的有效接收面积，θ为所述发射端的发射光学系统光轴与目标法向ON的夹角，R ij 为第i份子回波信号中第j个冲激响应对应的目标物与所述接收端之间的距离，
Figure PCTCN2019105439-appb-000002
为所述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、3……n，j为大于或等于1的正整数，需要说明的是，冲激响应值h ij是指冲激响应的幅度值。在本申请实施例中，子反射率计算公式是利用雷达方程反演出的反射率计算公式，本申请实施例在计算第i份子回波信号的子反射率时，将
Figure PCTCN2019105439-appb-000003
视为一个冲激响应的冲激响应值，用于代表发射信号在某一时刻目标物反射回的信号强度，因此可以根据第i份子回波信号中第j个冲激响应对应的冲激响应值获得的第i份子回波信号对应目标物的反射率信息，降低了反射率的计算难度。
在一种可能实现的方式中，上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值为去除上述接收端、信道和发射端中的一个或多个影响因素后的冲激响应值，影响因素包括损耗、滤波、衰减中的一种或多种。在本申请实施例中，在回波信号从接收端接收后，到通过探测器进行模数转换，再到处理器对转换后的信号进行处理的过程中，一方面会受到接收端、探测器等器件(例如：雪崩光电二极管、跨阻放大器、低通滤波器、模拟数字转换器等)的损耗、滤波或衰减的影响，另一方面由于接收端的效率、损耗也会给信号带来变化。因此在计算子反射率之前，需要将这些影响因素进行去耦合，再将去除影响后的冲激响应的值代入公式计算，能够得到更加精准的反射率结果。可以理解的是，去除影响后的冲激响应的值也为冲激响应的幅度值，去耦合的方法包括但不限于实际标定、器件与系统建模或二者的结合等。
在一种可能实现的方式中，上述将n份子反射率累加获得目标物的反射率，包括：根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，上述反射率计算公式为
Figure PCTCN2019105439-appb-000004
ρ i为所述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、3……n。在本申请实施例中，要得到目标物的总反射率信息，需要将所有的子回波信号分别通过雷达方程进行反演，得到子反射率信息，然后进行叠加得到总反射率即目标的反射率值。该方法将一个整体分为n份后再累加，而且在计算其中一份时不需要得知入射角、粗糙度等信息，模型简单而且不需要进行标定，能较好地适用于实时处理系统中，简单精确的计算物体的反射率。
在一种可能实现的方式中，上述预设第一时间间隔为所述目标物上、距离大于或者等于预设距离阈值的两个反射点分别反射的两个回波信号到达接收端的时间间隔。在本申请实施例中，需要说明的是，预设第一时间间隔是预先设置的、目标物上距离大于或者等于预设距离阈值的、两个反射点(该两个反射点可以是不同物体上的两个反射点，也可以是同一个物体上的不同反射点)反射的所述回波信号到达所述接收端的时间间隔，相当于回波信号的脉冲宽度，因此，计算目标物的反射率时，当每相邻两份子回波信号到达所述接收端的时间间隔大于预设第一时间间隔时，则认为是该两个反射点属于两个不同物体或者同一物体的不同部分。分别计算目标物不同部分的反射率后再累加，可以避免因发射信号受到入射角、目标物几何形状对计算目标物反射率的影响，提高了反射率的计算精度和效 率。
第二方面，本申请实施例提供了一种目标物的反射率计算装置，其特征在于，包括：
提取单元，用于从接收端接收的目标物反射回波信号中提取出n份子回波信号，其中，上述n份子回波信号中的每相邻两份子回波信号到达上述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；
子反射率单元，用于计算上述n份子回波信号中每一份子回波信号的子反射率；
反射率单元，用于将n份子回波信号的子反射率累加获得目标物的反射率。
在一种可能实现的方式中，n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。
在一种可能实现的方式中，上述装置还包括：响应估计单元，用于在从接收端接收的目标物反射的回波信号中提取出n份子回波信号之前，通过最小二乘法或最小均方差法对上述回波信号进行响应估计，获得上述回波信号对应的m个冲激响应，m为大于或等于1的正整数；第一确定单元，用于在从接收端接收的目标物反射的回波信号中提取出n份子回波信号之后，根据m个冲激响应，计算n份子回波信号中每一份子回波信号对应的一个或多个冲激响应的冲激响应值；计算n份子回波信号中每一份子回波信号的子反射率包括：根据每一份子回波信号对应的一个或多个冲激响应的冲激响应值计算对应的子回波信号的子反射率。
在一种可能实现的方式中，上述提取单元具体用于：根据上述m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，上述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，上述预设第二时间间隔为小于预设第一时间间隔的预设时间间隔，z为大于或等于n的正整数，且m为大于或等于z的正整数；去除上述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，上述n个冲激响应集合与上述n份子回波信号一一对应，且包括上述n份子回波信号对应的冲激响应。
在一种可能实现的方式中，上述提取单元具体用于：根据上述回波信号确定k个信号集合，其中，每一个信号集合中包括的多个回波中的每相邻两个回波到达上述接收端的时间间隔在预设第三时间间隔内，上述k个信号集合中任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；确定上述k个信号集合的每一个信号集合中所有回波的幅度门限；去除上述k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，上述n个信号集合与上述n份子回波信号一一对应。
在一种可能实现的方式中，上述装置还包括：第二确定单元，用于在上述计算上述n份子回波信号中每一份子回波信号的子反射率之前，确定上述n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；上述子反射率单元具体用于：根据上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算上述n份子回波信号中每一份子回波信号的子反射率。
在一种可能实现的方式中，上述子反射率单元具体用于：根据激光在大气中的单程透 射率、接收光学系统的效率、接收端的有效接收面积，确定第一比值；将n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与第一比值分别相乘后累加，获得n份子回波信号中每一份子回波信号的子反射率。
在一种可能实现的方式中，上述子反射率单元具体用于：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算n份子回波信号中每一份子回波信号的子反射率，其中，子反射率计算公式为：
Figure PCTCN2019105439-appb-000005
Figure PCTCN2019105439-appb-000006
其中，ρ i为上述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为上述接收端的有效接收面积，θ为上述发射端的发射光学系统光轴与目标法向ON的夹角，R ij为第i份子回波信号中第j个冲激响应对应的目标物与上述接收端之间的距离，
Figure PCTCN2019105439-appb-000007
为上述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、3……n，j为大于或等于1的正整数。
在一种可能实现的方式中，上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值为去除上述接收端、信道和发射端中的一个或多个影响因素后的冲激响应值，上述影响因素包括损耗、滤波、衰减中的一种或多种。
在一种可能实现的方式中，上述反射率单元具体用于：根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，上述反射率计算公式为
Figure PCTCN2019105439-appb-000008
ρ i为上述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、3……n。
在一种可能实现的方式中，上述预设第一时间间隔为所述目标物上、距离大于或者等于预设距离阈值的两个反射点分别反射的两个回波信号到达接收端的时间间隔。
第三方面，本申请实施例提供了一种激光雷达，其特征在于，包括：接收端和处理器；其中，上述接收端，用于接收目标物反射的回波信号；上述处理器，用于：从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，上述n份子回波信号中的每相邻两份子回波信号到达上述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；计算上述n份子回波信号中每一份子回波信号的子反射率；将n份子回波信号的子反射率累加获得目标物的反射率。
在一种可能实现的方式中，上述接收端，具体用于接收目标物反射的模拟回波信号；上述激光雷达还包括探测器，上述接收端、上述处理器分别与上述探测器耦合；上述探测器，用于将上述接收端接收的上述模拟回波信号进行模数转换，并将进行模数转换后的回波信号发送给上述处理器；上述处理器，具体用于：从上述进行模数转换后的回波信号中提取出n份子回波信号，其中，上述n份子回波信号中的每相邻两份子回波信号对应的模拟回波信号到达上述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；计算上述n份子回波信号中每一份子回波信号的子反射率；将n份子回波信号的子反 射率累加获得目标物的反射率。
在一种可能实现的方式中，n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。
在一种可能实现的方式中，上述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号之前，上述处理器还用于：通过最小二乘法或最小均方差法对上述回波信号进行响应估计，获得上述回波信号对应的m个冲激响应，m为大于或等于1的正整数；上述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号之后，上述处理器还用于：根据m个冲激响应，计算n份子回波信号中每一份子回波信号对应的一个或多个冲激响应的冲激响应值；计算n份子回波信号中每一份子回波信号的子反射率包括：根据每一份子回波信号对应的一个或多个冲激响应的冲激响应值计算对应的子回波信号的子反射率。
在一种可能实现的方式中，上述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号时，上述处理器具体用于：根据上述m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，上述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，上述预设第二时间间隔为小于预设第一时间间隔的预设时间间隔，z为大于或等于n的正整数，且m为大于或等于z的正整数；去除上述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，上述n个冲激响应集合与上述n份子回波信号一一对应，且包括上述n份子回波信号对应的冲激响应。
在一种可能实现的方式中，上述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号时，上述处理器具体用于：根据上述回波信号确定k个信号集合，其中，每一个信号集合中包括的多个回波中的每相邻两个回波到达上述接收端的时间间隔在预设第三时间间隔内，上述k个信号集合中任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；确定上述k个信号集合的每一个信号集合中所有回波的幅度门限；去除上述k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，上述n个信号集合与上述n份子回波信号一一对应。
在一种可能实现的方式中，上述处理器用于计算上述n份子回波信号中每一份子回波信号的子反射率之前，上述处理器还用于：确定上述n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；上述处理器用于计算上述n份子回波信号中每一份子回波信号的子反射率时，上述处理器具体用于：根据上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算上述n份子回波信号中每一份子回波信号的子反射率。
在一种可能实现的方式中，上述处理器用于根据上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算上述n份子回波信号中每一份子回波信号的子反射率时，上述处理器具体用于：根据激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积，确定第一比值；将n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与第一比值分别相乘后累加，获得n份子回波信号中每一份子回波信 号的子反射率。
在一种可能实现的方式中，上述处理器用于根据上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算上述n份子回波信号中每一份子回波信号的子反射率时，上述处理器具体用于：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算n份子回波信号中每一份子回波信号的子反射率，其中，子反射率计算公式为：
Figure PCTCN2019105439-appb-000009
其中，ρ i为上述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为上述接收端的有效接收面积，θ为上述发射端的发射光学系统光轴与目标法向ON的夹角，R ij为第i份子回波信号中第j个冲激响应对应的目标物与上述接收端之间的距离，
Figure PCTCN2019105439-appb-000010
为上述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、3……n，j为大于或等于1的正整数。
在一种可能实现的方式中，上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值为去除上述接收端、信道和发射端中的一个或多个影响因素后的冲激响应值，上述影响因素包括损耗、滤波、衰减中的一种或多种。
在一种可能实现的方式中，上述处理器用于将n份子反射率累加获得目标物的反射率时，上述处理器具体用于：根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，上述反射率计算公式为
Figure PCTCN2019105439-appb-000011
ρ i为上述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、3……n。
在一种可能实现的方式中，上述预设第一时间间隔为所述目标物上、距离大于或者等于预设距离阈值的两个反射点分别反射的两个回波信号到达接收端的时间间隔。
第四方面，本申请实施例提供一种服务设备，该服务设备中包括处理器，处理器被配置为支持该服务设备执行第一方面提供的一种目标物的反射率计算方法中相应的功能。该服务设备还可以包括存储器，存储器用于与处理器耦合，其保存该服务设备必要的程序指令和数据。该服务设备还可以包括通信接口，用于该服务设备与其他设备或通信网络通信。
第五方面，本申请实施例提供了一种计算机程序，该计算机程序包括指令，当该计算机程序被计算机执行时，使得计算机可以执行上述第二方面中的目标物的反射率计算装置所执行的流程。
第六方面，本申请实施例提供一种计算机存储介质，用于储存为上述第二方面提供的一种目标物的反射率计算装置所用的计算机软件指令，其包含用于执行上述方面所设计的程序。
第七方面，本申请实施例提供了一种芯片系统，该芯片系统包括处理器，用于支持网络设备实现上述第一方面中所涉及的功能。在一种可能的设计中，所述芯片系统还包括存储器，所述存储器，用于保存数据发送设备必要的程序指令和数据。该芯片系统，可以由 芯片构成，也可以包含芯片和其他分立器件。
第八方面，本申请实施例提供一种电子设备，包括上述第一方面中的任意一种实现方式所提供的处理芯片以及耦合于所述芯片的分立器件。
附图说明
为了更清楚地说明本申请实施例或背景技术中的技术方案，下面将对本申请实施例或背景技术中所需要使用的附图进行说明。
图1是本申请实施例提供的一种基于强度反演的反射率计算方法流程示意图。
图2是本申请实施例提供的一种反射率的能量估计示意图。
图3是本申请实施例提供的一种基于强度反演方法的雷达系统架构图。
图4是本申请实施例提供的一种激光雷达系统框架示意图。
图5A是本申请实施例提供的一种目标物的反射率计算方法的流程示意图。
图5B是本申请实施例提供的一种从m个冲激响应中确定出n个冲激响应集合的示意图。
图5C是本申请实施例提供的一种回波信号的波形图。
图5D是本申请实施例提供的该一种回波信号对应的冲激响应示意图。
图5E是本申请实施例提供的一种目标物的反射率计算方法与上述方案二中一种基于强度反演的反射率计算方法的计算结果对比图。
图6是本申请实施例提供的另一种目标物的反射率计算方法的流程示意图。
图7是本申请实施例提供的一种目标物的反射率计算装置的结构示意图。
图8是本申请实施例提供的另一种目标物的反射率计算装置的结构示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例进行描述。
本申请的说明书和权利要求书及所述附图中的术语“第一”和“第二”等是用于区别不同对象，而不是用于描述特定顺序。此外，术语“包括”和“具有”以及它们任何变形，意图在于覆盖不排他的包含。例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备没有限定于已列出的步骤或单元，而是可选地还包括没有列出的步骤或单元，或可选地还包括对于这些过程、方法、产品或设备固有的其它步骤或单元。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本说明书中使用的术语“部件”、“模块”、“系统”等用于表示计算机相关的实体、硬件、固件、硬件和软件的组合、软件、或执行中的软件。例如，部件可以是但不限于，在处理器上运行的进程、处理器、对象、可执行文件、执行线程、程序和/或计算机。通过图示，在计算设备上运行的应用和计算设备都可以是部件。一个或多个部件可驻留在进程和/或执行线程中，部件可位于一个计算机上和/或分布在2个或更多个计算机之间。此外，这些部 件可从在上面存储有各种数据结构的各种计算机可读介质执行。部件可例如根据具有一个或多个数据分组(例如来自与本地系统、分布式系统和/或网络间的另一部件交互的二个部件的数据，例如，通过信号与其它系统交互的互联网)的信号通过本地和/或远程进程来通信。
首先，对本申请中的部分用语进行解释说明，以便于本领域技术人员理解。
(1)反射率，投射到物体上面被反射的辐射能与投射到物体上的总辐射能之比，称为该物体的反射率。这是针对所有波长而言，应称为全反射率，通常简称为反射率。
(2)最小二乘法(Least Squares Method，LS)，又称最小平方法，是一种数学优化技术，通过最小化误差的平方和寻找数据的最佳函数匹配。利用最小二乘法可以简便地求得未知的数据，并使得这些求得的数据与实际数据之间误差的平方和为最小。
(3)最小均方误差(Minimum Mean-Square Error，MMSE)，是在某一约束条件下，均方误差的最小值，MMSE的优化目标是为了使基于接收数据的估计值和目标数据的均方误差最小化，其中，均方误差(mean-square error,MSE)是反映估计量与被估计量之间差异程度的一种度量。
(4)回波，回波即反射波。因为波的发送实际上也是能量的传送过程，所以当接收端不能完全吸收波的能量时(如，阻抗不匹配时)，波的一部分能量会被反射回来，就形成了回波。是指通过不同于正常路径的其他途径而到达给定点上的信号，在该点上，此信号有足够的大小和时延，以致可觉察出它与由正常路径传送来的信号有区别。
(5)冲激响应，系统在单位冲激函数激励下引起的零状态响应被称之为该系统的“冲激响应”。它与系统的传递函数互为傅里叶变换关系，而且冲激响应是完全由系统本身的特性所决定，与系统的激励源无关，是用时间函数表示系统特性的一种常用方式。在连续时间系统中，任一个信号可以分解为具有不同时延的冲激信号的叠加，进而在进行实际分析时，可通过电路分析法求解微分方程或采用解卷积的方法，计算出系统的冲激响应。
(6)激光雷达(Light Detection And Ranging，LiDAR)，是以发射激光束探测目标的位置、速度等特征量的雷达系统。其工作原理是向目标发射探测信号(激光束),然后将接收到的从目标反射回来的信号(目标回波)与发射信号进行比较，作适当处理后,就可获得目标的有关信息，如目标距离、方位、高度、速度、姿态、甚至形状等参数，从而对飞机、导弹等目标进行探测、跟踪和识别。它由激光发射机、光学接收机、转台和信息处理系统等组成，激光器将电脉冲变成光脉冲发射出去，光接收机再把从目标反射回来的光脉冲还原成电脉冲，送到显示器。
(7)双向反射分布函数(Bidirectional Reflectance Distrbtion Function，BRDF)是用来定义给定入射方向上的辐射照度如何影响给定出射方向上的辐射率。更笼统地说，它描述了入射光线经过某个表面反射后如何在各个出射方向上分布这可以是从理想镜面反射到漫反射、各向同性或者各向异性的各种反射。
(8)模拟数字转换器(Analog Digital Converter，ADC)，即模数变换器，也简称“模数转换器”，是一种把模拟量转换为数字量的装置。在计算机控制系统中，须经各种检测装置，以连续变化的电压或电流作为模拟量，随时提供被控制对象的有关参数(如速度、压 力、温度等)而进行控制。但是由于计算机的输入必须是数字量，所以需用模数转换器达到控制目的。
(9)雪崩光电二极管(Avalanche photodiode，APD)，又称累崩光电二极管或崩溃光二极体，是一种半导体光检测器，其原理类似于光电倍增管。
(10)跨阻放大器(Trans Impedance Amplifier，TIA)，是放大器类型的一种，放大器类型是根据其输入输出信号的类型来定义的。在电学范畴，假设放大器增益A＝Y/X，Y为输出，X为输入。由于表征一个信号不是用电压就是电流，所以组合一下就有4种放大器，当输入为电流信号，输出为电压信号时，A＝Y(电压)/X(电流)，具有电阻的量纲，所以一般称之为跨阻放大器。
(11)低通滤波器(Low-Pass Filter，LPF)容许低频信号通过，但减弱(或减少)频率高于截止频率的信号的通过。低通滤波器在信号处理中的作用等同于其它领域如金融领域中移动平均数(moving average)所起的作用；这两个工具都是通过剔除短期波动、保留长期发展趋势提供了信号的平滑形式。
(12)离散傅里叶变换(Discrete Fourier Transform，DFT)，是傅里叶变换在时域和频域上都呈离散的形式，将信号的时域采样变换为其离散时间傅里叶变换的频域采样。在形式上，变换两端(时域和频域上)的序列是有限长的，而实际上这两组序列都应当被认为是离散周期信号的主值序列。即使对有限长的离散信号作DFT，也应当将其看作其周期延拓的变换。在实际应用中通常采用快速傅里叶变换计算DFT。
(13)维纳滤波，一种以最小平方为最优准则的线性滤波器。在一定的约束条件下，其输出与一给定函数(通常称为期望输出)的差的平方达到最小，通过数学运算最终可变为一个托布利兹方程的求解问题。维纳滤波器又被称为最小二乘滤波器或最小平方滤波器，目前是基本的滤波方法之一。
(14)数字信号处理(Digital Signal Processing，DSP)，即信号数字化处理。将事物的运动变化转变为一串数字，并用计算的方法从中提取有用的信息，以满足我们实际应用的需求。
其次，分析并提出本申请的应用场景以及所具体要解决技术问题。
应用场景：在现有技术中，激光雷达是采用从紫外波段到远红外波段(250nm-11um)电磁波，通过探测目标的散射光特性来获取目标相关信息的光学遥感技术。激光雷达具有高测量精度、精细的时间和空间分辨率，能完成测距、目标探测、跟踪和成像识别等功能，可应用于智能交通、自动驾驶、大气环境监测、地理测绘、无人机等领域。在激光雷达的应用场景中，目标物的反射率信息可以提供诸如颜色、材质、形状等各种物体的重要信息，给物体分割、目标识别等提供重要帮助。关于反射率计算的技术包括下述方案：
方案一，该方法首先获取标准反射率物体的第一实测反射率，然后根据标准物体的真实反射率与实测反射率进行对比，计算得到标准物体处于该位置的光路衰减值。根据光路衰减值计算补偿值，对第一实测反射率进行补偿，得到真实的反射率信息。例如：目标辐照特性建模法，基于双向反射分布函数等方法对目标物的反射特性进行建模，可以较为精确地得到朗伯反射下反射光的能量、成分和偏振态等信息。
方案二，现有算法为了提高强度估计的准确性，采用能量估计与线性拟合的方法。例如：根据强度信息反演法，该方法需要准确得知目标物回波的强度信息，将其带入雷达方程对其他参数进行解耦和得到反射率信息。请参考附图1、附图2和附图3，图1是本申请实施例提供的一种基于强度反演的反射率计算方法流程示意图，图2是本申请实施例提供的一种反射率的能量估计示意图，适用于该方案的反射率计算流程，图3是本申请实施例提供的一种基于强度反演方法的雷达系统架构图。如图1所示，激光雷达10接收回波信号322，激光雷达10中的探测器302包含光敏原件304、放大器306、时间/数字转换器308，积分器310和模拟/数字转换器312等，其中，放大器306包括跨阻放大器316和电压增益放大器318。时间/数字转换器308和对应的数据通道324、以及模拟/数字转换器312和对应的数据通道326在发射信号发出后均保持工作直至反射信号接收完成。如图2所示，时间/数字转换器308针对信道1产生两个停止(406,410)，针对信道2产生两个停止(408,412)。信号的斜率可以由这几个时间戳进行计算，然后通过线性拟合等方法估计回波脉冲的最大值(即峰值)。考虑到噪声等影响因素的存在，仅依赖于时间/数字转换器308的输出进行反射能量的估计值可能是不准确的，因此，现有方案还可以包含平行于时间/数字转换器308的积分器310。积分器310积累所接收的所有反射脉冲产生的电荷及接收期间的噪声，同时模拟/数字转换器312将扫描间隔期间的积分器积累电荷进行数字化。通过处理器对积分器310数字化后的值与对时间/数字转换器308数据进行综合处理，得到反射率信息。这种单峰值点估计或峰值叠加的方法，可以应用在实时处理系统中，估算目标物体的反射率。
上述方案一适用于反射率要求精度较高的场景中，上述方案二适用于实时系统中，满足了当今生活中的大多数的反射率计算需求，但存在以下多个缺点：
方案一缺点，该方案根据标准反射率物体进行标定(例如：需要得知入射角、粗糙度等信息)，可以对各种影响因素去耦合，得到精确的反射率信息，但该方法需要大量的标定工作，在复杂环境下难以实现精确的反射率实时输出，而且该方法所使用的模型复杂且需要一定的标定工作，往往需要通过离线计算，因此难以应用在实时处理系统中，应用场景有限。
方案二缺点，该方案可以应用在实时系统中，但是需要硬件两路处理，增加的整个系统的硬件复杂度，而且在实际系统中，回波信号的波形会因为入射角以及目标物的几何形状的影响，会有较大变化(展宽、畸变等)，进一步的，该方法所用的线性拟合等技术会引入额外的偏差，难以通过积分器的方法进行校正。
综上所述，由于目标物的几何形状不同或者与发射端和/或接收端之间的距离不同，会导致发射信号照射在目标物上的时间以及入射角不同，进而造成接收端接收从目标物反射回的回波的时间不同，即，不同回波信号到达接收端的时间不同，回波信号到达接收端时经过的距离也不同。因此现有的方法进行反射率估算时所使用的回波信号强度信息容易受到入射到目标物上的入射角、以及目标物几何形状等因素影响，受到影响后可能导致在该方法的估计过程中引入比较大的偏差，进而给反射率的准确估计带来困难。因此在本申请提供的反射率计算方法可以用于解决在实时系统中，因发射信号照射在目标物上的时间以及入射角不同，进而造成接收端接收从目标物反射回的回波的时间不同，对回波信号强度造成的影响，以及如何在实时处理系统中，简单精确的计算物体的反射率的问题。
基于上述提出的技术问题以及应用场景，也为了便于理解本申请实施例，下面先对本申请实施例所基于的其中一种激光雷达系统进行描述。请参考附图4，图4是本申请实施例提供的一种激光雷达系统框架示意图，激光雷达20包括接收端401和处理器403，还可以包括探测器402。
所述接收端401，具体用于接收模拟回波信号。需要说明的是，激光雷达的接收端可以是由接收器、各种形式的光电探测器和其他相关器件等耦合而成，其中，接收器可以准确地测量发射信号(如：光脉冲)从发射到被反射回接收端的传播时间，光电探测器可以包括：光电倍增管、半导体光电二极管、雪崩光电二极管、红外和可见光多元探测器件等组合。激光雷达接收到目标物体的反射光后，还需要将光信号转换为电信号(即：模拟回波信号)。需要说明是的，接收端401可以在一个扫描周期内得到一帧数据，一帧数据中接收视场内(即：目标区域)的每个距离测量单元为一个像素。
所述处理器403，具体用于：从所述进行模数转换后的回波信号中提取出n份子回波信号，其中，所述n份子回波信号中的每相邻两份子回波信号对应的模拟回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；计算所述n份子回波信号中每一份子回波信号的子反射率；将所述n份子回波信号的子反射率累加获得所述目标物的反射率。因此，将回波信号提取n份子回波信号，计算n份子回波信号的子反射率后再累加获得整个目标物的反射率，避免了因发射信号受到入射角以及目标物几何形状对计算目标物反射率的影响，而且方法简单，可以在实时处理系统中，简单精确的计算物体的反射率，提高了反射率的计算精度和效率。
所述激光雷达20还包括探测器402，所述接收端401、所述处理器403分别与所述探测器402耦合。所述探测器402，用于将所述接收端401接收的所述模拟回波信号420进行模数转换，并将进行模数转换后的回波信号发送给所述处理器。可选的，所述探测器402还可以包括二极管412(如：雪崩光电二极管)、放大器422(如，跨阻放大器452、信号放大器462等)、滤波器432(如：低通滤波器)、模拟数字转换器442中的一个或多个。所述探测器接收到接收端的模拟电信号后，可以首先通过二极管进行光电转换；然后将光电转换后的模拟电信号输入放大器中，获得放大后的模拟电信号；再将放大后的模拟电信号通过滤波器滤除信号中的干扰，最后将滤除干扰后的模拟电信号通过模数转换器转换成数字信号，以便后续处理器能够正常处理数据。例如：回波信号04经过雪崩光电二极管、跨阻放大器和低通滤波器的放大滤波后，通过模拟数字转换器进行数模转换，然后将转换后的回波信号送入处理器进行信号处理。
可以理解的是，所述接收端401可以与激光雷达20包括的探测器402集成到一组硬件设备上。
需要说明的是，所述处理器在回波信号经过探测器402处理后，具体用于：从所述进行模数转换后的回波信号中提取出n份子回波信号，计算所述n份子回波信号中每一份子回波信号的子反射率；将n份子反射率累加获得目标物的反射率。其中，所述n份子回波信号中的每相邻两份子回波信号对应的模拟回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数。即，处理器根据回波信号计算反射率时，所 述回波信号均属于数字信号。
综上所述，激光雷达系统可以在一个扫描周期内得到一帧数据，一帧数据中接收视场内的每个距离测量单元为一个像素。单个像素内，可以接收到模拟数字转换器采样后的整个回波信息，包括回波的延时、波形、峰值等信息。根据回波信号的这些信息与反射信号的波形、幅度、峰值等信息进行反卷积，即可以得到回波信号所经历的整个系统冲激响应。所得到的冲激响应是包含发射系统、信道、目标物、接收端、噪声等各个部分或模块的总响应，它们共同作用使得信号具有幅度、延时、畸变等变化。在获得系统总响应之后，要准确估计目标物的反射率信息，需要将除目标物外的发射系统、信道、接收端、噪声等剩余部分的响应从回波信号所经历的整个系统冲激响应中去耦合，得到纯净的目标物响应信息，才能准确获知目标物材质、颜色、形状等因素的影响，进而准确估计目标物的反射率。
还需要说明的是，图1的激光雷达系统架构只是本申请实施例中的部分示例性的实施方式，本申请实施例中的激光雷达系统架构包括但不仅限于以上激光雷达系统架构。
基于图4提供的激光雷达20，结合本申请中提供的反射率计算方法，对本申请中提出的技术问题进行具体分析和解决。
参见图5A，图5A是本申请实施例提供的一种目标物的反射率计算方法的流程示意图，该方法可应用于上述图4中所述的激光雷达中，其中的激光雷达20可以用于支持并执行图5A中所示的方法流程步骤S501-步骤S503。该方法可以包括以下步骤S501-步骤S503。
步骤S501：从接收端接收的目标物反射的回波信号中提取出n份子回波信号。
具体地，反射率计算装置可以从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，所述n份子回波信号中的每相邻两份子回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数。接收端接收的回波信号为目标物(目标物可以为一个目标物体或者目标区域内多个物体)收到发射端发射到该物体表面的发射信号后将该发射信号反射回接收端的信号，其中，反射率计算装置为目标物的反射率计算装置，例如：可以是上述图4中的激光雷达20，也可以是上述激光雷达20中的某一部分。需要说明的是，因为目标物的几何形状不同，或者目标物与发射端和/或接收端之间的距离不同，会导致发射信号照射在目标物上的时间以及入射角不同，进而造成接收端接收从目标物表面反射回的回波的时间不同(即，不同回波信号的时延不同)，回波信号到达接收端时经过的距离也不同，所以在进行反射率计算时所使用的回波信号强度信息很容易受到入射到目标物上的入射角、以及目标物几何形状等因素影响。为了避免计算目标区域内物体或者目标物时，受到发射信号在该物体表面上的入射角、以及该物体几何形状等因素影响，而且又因为物体的反射回的能量可以视为是固定的一份，然后将一整份反射回的能量分为n小份后再累加，仍然可以得到完整的一份能量，所以反射率计算装置可以从接收端接收的目标物反射的回波信号中提取n份子回波信号，再计算目标物的反射率。
还需要说明的是，从接收端接收的目标物反射的回波信号中提取出的n份子回波信号可以是在回波信号中把符合条件(即，不同目标物或者目标物的不同部分分别反射回接收端的信号)的子回波信号全部提取出来总共为n份，还可以是在符合条件的全部子回波信号中选择性的提取其中的n份。例如：为了反射率计算的简单快捷，可以在提取出的五份 子回波信号中选择信号强度最强的三份子回波信号，以代表接收端接收的全部信号。可以理解的是，因为目标物体反射回接收端的信号会被分配为不同时间延迟、不同能量的若干份，所以一份子回波信号可以代表一个物体，或者，代表一个物体的某一部分。举例来说：若接收端接收从目标物反射回的任意两个回波的时间相近，如：在预设第一时间间隔内，并且回波的信号强度相似，则可以认为该两个回波可以是同一个目标物的同一部分反射回接收端的回波信号，所以按照接收端接收回波的时间先后不同，在每相邻两份回波的时间间隔大于预设第一时间间隔，且信号强度相差较大时认为上述两份回波属于不同份的子回波信号。还需要说明的是，当n＝1时，可以认为从接收端接收的目标物反射的回波信号中提取出的1份子回波信号，该子回波信号包含到达接收端的相邻两个回波全部都在预设第一时间间隔内，进一步的，可以将该子回波信号的子反射率为该目标物体的反射率；当n＝1时，还可以认为是在符合条件的全部子回波信号中选择性的提取其中的1份，仅仅通过该一份子回波信号中计算得到的反射率为该目标物体的反射率。可以理解的是，本申请实施例实际是以一种类似微积分的方法将脉冲对应的响应(即每份子回波信号中的回波)带入雷达方程，虽然n＝1，但该子回波信号包含了许多回波，即该子回波信号包含的脉冲可能会是几十个或更多。还需要说明的是，本申请实施例可以应用于时效性要求较高的车载雷达的场景中，以便实时分辨车辆周围物体的反射率，监控车辆周围物体，帮助司机判断车辆周围的路况，保证司机正常驾驶等。例如，可以在识别道路上的不明移动目标或者固定目标时，通过计算移动目标的反射率，确定不明目标的种类(如：行人、车桩、车辆或动物等等)。又例如，在车载雷达识别路标时，可以通过计算路标上的不同颜色的反射率，实现路标图形的识别。本申请实施例中的反射率计算方法还可以应用于空中识别的场景，在激光雷达识别空中不明飞行物时，可以通过确定目标空域内飞行物体的反射率，实现飞行物体的材料种类识别。又因为本申请实施例提供的方法是根据不同入射角返回的回波信号的系统响应估计确定物体的反射率，所以本申请中的反射率计算方法可以应用于识别不规则形状物体的反射率的应用场景；又因为反射率是物体的固有属性之一，所以本申请中的反射率计算方法还可以应用于通过反射率识别物体材质或种类的应用场景。
可选的，n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。在提取n份子回波信号时需要将信号强度不大于信号强度阈值的回波剔除，因为只有当回波信号强度在信号强度阈值以上时，才认为该回波信号是目标物反射回接收端的回波信号，若回波信号的强度太弱则可以认为是干扰反射回的信号，所以可以忽略该回波信号。例如：信号强度阈值的大小可以设置为虚警概率为千分之一时对应的信号强度，需要说明的是，在激光雷达检测物体的应用场景下，虚警概率是指在激光雷达探测的过程中，采用门限检测的方法时由于噪声的普遍存在和起伏，会提升实际不存在目标物体却被激光雷达判断为有目标物体的概率。因此，每一份子回波信号的信号强度大于信号强度阈值，可以有效的降低其他干扰对计算目标物反射率的影响，提高了计算物体反射率的精度。
在一种可能实现的方式中，反射率计算装置在提取n份子回波信号前，可以将回波信号由时域信号转变为频域信号的冲激响应，冲激响应可以与发射信号卷积后得到反射的回波信号，因此，冲激响应能够直观的表现出发射信号在某一时刻反射回的信号强度。可选的，所述从接收端接收的目标物反射的回波信号中提取出n份子回波信号，包括：根据所 述m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，所述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，z为大于或等于n的正整数，且m为大于或等于z的正整数；去除所述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，所述n个冲激响应集合与所述n份子回波信号一一对应，且包括所述n份子回波信号对应的冲激响应。从m个冲激响应中确定出n个冲激响应集合，上述n个冲激响应集合中每一个冲激响应集合都分别对应n份子回波信号中的一份子回波信号，n个冲激响应集合中每一个冲激响应集合中包括一个或多个冲激响应值均大于或等于响应阈值的冲激响应，而且该一个或多个冲激响应在m个冲激响应中与其相邻的至少一个冲激响应之间的时间间隔小于预设第二时间间隔，其中，预设第二时间间隔要小于预设第一时间间隔，预设第二时间间隔可以是脉宽的某个比例或其他自适应区间或者固定区间。
可以理解的是，在判断冲激响应值与响应阈值之间的大小关系时，是指上述冲激响应的绝对幅度值与响应阈值之间的大小关系。其中，需要说明的是，由于冲激响应值是指冲激响应的幅度值，且因为频谱泄露等因素影响，每一个子回波的冲激响应类似辛格函数(Sinc)分布，同时包含正负幅度。即，冲激响应的冲激响应值可以为负值，当冲激响应值为负值时，冲激响应值的绝对值均大于或等于响应阈值。在目标物体的响应估计上，可以系统的响应分为冲激响应之和，如下式所示：
Figure PCTCN2019105439-appb-000012
其中，接收到的回波信号在无噪声与有噪声存在下的表示分别为：
无噪声：
Figure PCTCN2019105439-appb-000013
有噪声：
Figure PCTCN2019105439-appb-000014
其中，S r(t)为接收到的回波信号，s(t)为发射信号，M为目标物体的响应个数，σ i为目标物体的散射特性，τ i为信号在发射端与接收端之间的目标往返时间，n(t)为噪声。可以看到，我们将目标物体的响应分为若干个冲激响应的集合后，反射信号的变化分为两部分，一个是散射特性σ i，它直接与目标物的反射率相关，反映了冲激响应的幅度；另一个是信号的延时τ i，它与测量距离相关。从上述两个角度上讲，冲激响应对系统响应的影响是延时和幅度变化。可以得出，在某个固定延时τ i的冲激响应幅度σ i等于延时τ i的这部分信号的接收信号与发射信号峰值功率之比P Ri/P Ti。
请参考附图5B，图5B是本申请实施例提供的一种从m个冲激响应中确定出n个冲激响应集合的示意图。根据m＝14个冲激响应确定z＝3个冲激响应集合，其中，z＝1的冲激响应集合中包括冲激响应1、2、3、4、5；z＝2的冲激响应集合中包括冲激响应6、7、8、9、10；z＝3的冲激响应集合中包括冲激响应11、12、13、14。去除所有冲激响应集合的每一个冲激响应集合中冲激响应值(即：冲激响应幅度的绝对值)小于响应阈值h的冲激响应 后，获得n＝2个冲激响应集合，其中，z＝3的冲激响应集合因为不包含冲激响应值大于响应阈值h的冲激响应，所以被去除。又因为所述n＝2个冲激响应集合与所述n＝2份子回波信号一一对应，所以从接收端接收的目标物反射的回波信号中提取出了n＝2份子回波信号，其中，n＝1的子回波信号中包含冲激响应3、4和5；n＝2的子回波信号中包含冲激响应8和9。请参考附图5C-图5D，图5C是本申请实施例提供的一种回波信号的波形图；图5D是本申请实施例提供的该一种回波信号对应的冲激响应示意图。由上述两幅仿真图可以直观的看出，目标物体反射回接收端的回波信号中可以包括多个子回波信号，每个子回波信号都可以对应多个冲激响应。因此，本申请实施例中的反射率计算装置可以准确地从多个目标物或者不规则几何形状的目标中中，确定出来自于同一个目标物或者一个目标物相同部分的回波，进而避免后续在反射率的计算过程中目标物几何形状、或不同目标物反射率等因素影响，提高了反射率的计算精度。该方法采用目标物响应估计的方法，有效解决反射率计算中的目标物形状、入射角引起的模糊问题，可用于实时性要求较高的雷达中。
在一种可能实现的方式中，当反射率计算装置接收回波信号的波形信息受到了强烈的干扰时，可能会导致回波信号的波形发生剧烈的形变。因此，在从接收端接收的目标物反射的回波信号中提取出n份子回波信号时，即需要满足一定幅度门限(如：虚警门限或其他门限)以保证提取出的子回波信号对应的为真实目标物而不是其它干扰。当输出信噪比不是按比例随着输入信噪比下降，而是急剧恶化，即，当包络检波器的输入信噪比降低到一个特定的数值后，检波器的输出信噪比出现急剧下降的一种现象为门限效应，开始出现门限效应的输入信噪比称为门限值。
因此，反射率计算装置从接收端接收的目标物反射的回波信号中提取出n份子回波信号，可以包括：根据所述回波信号确定k个信号集合，其中，每一个信号集合中包括的多个回波中的每相邻两个回波到达所述接收端的时间间隔在预设第三时间间隔内，所述k个信号集合中任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；确定所述k个信号集合的每一个信号集合中所有回波的幅度门限；去除所述k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，所述n个信号集合与所述n份子回波信号一一对应。从在k个信号集合中确定出的n个信号集合中每一个信号集合都分别对应n份子回波信号中的一份子回波信号，n个信号集合中每一个信号集合中包括一个或多个幅度门限均大于预设幅度门限阈值的回波，而且该一个或多个回波在到达接收端时与其相邻的至少一个回波之间的时间间隔小于预设第三时间间隔，确定采样区间(时间范围)可以是脉宽的某个比例或其他自适应区间或者固定区间。需要说明的是，预设第三时间间隔和预设第一时间间隔实质上是一个东西，都是为了区分两个不同物体或者同一物体的不同部分(即，反射点)的回波，即可选的，预设第三时间间隔也可以为目标物上、距离大于或者等于预设距离阈值的两个反射点反射的回波到达接收端的时间间隔，预设第三时间间隔可以小于或等于预设第一时间间隔，大于预设第二时间间隔，子回波信号包括多个回波，当其中两个回波间隔在预设第三时间间隔内认为是属于一个子回波，当两个回波间隔在预设第三时间间隔外则认为是分别属于两个子回波。预设第三时间间隔实际上可以比预设第一时间间隔设置的更小一些，以便剔除在同一份子回波信号中时间间隔差别比较大的信号，即对应目标物之间的距离稍远的回波信号，以达到精确计算 目标物发反射率的目的。综上所述，本申请实施例通过确定信号集合中满足幅度门限的信号提取为子回波信号，可以较为准确地从目标区域内多个目标物或者不规则几何形状的目标中，确定出来自真实目标物的回波，进而避免后续在反射率的计算过程中受到干扰目标物等因素影响，提高了反射率的计算精度。
在一种可能实现的方式中，反射率计算装置从接收端接收的目标物反射的回波信号中提取出n份子回波信号可以包括：在一定的采样区间内(例如：从时间范围上说，可以是脉宽的某个比例或其他自适应区间或者固定区间为采样区间)，对从接收端接收的目标物反射的回波信号进行响应估计，获得所述回波信号对应的冲激响应h(n)；确定h(n)的所有拐点后，提取出满足距离间隔τ(可以根据光速与时间确定)的最大的n个拐点；截取符合要求的拐点附件所有小于一定间隔(例如：两倍发射信号脉宽)的所有冲激响应的值。
可选的，预设第一时间间隔是预先设置的、目标物上距离大于或者等于预设距离阈值的、两个反射点(该两个反射点可以是不同物体上的两个反射点，也可以是同一个物体上的不同反射点)反射的所述回波信号到达所述接收端的时间间隔，相当于回波信号的脉冲宽度，其中，预设距离阈值的范围可以是0.1m-1m，预设第一时间间隔可以通过预设距离阈值与光速的比值计算。比如，预先设置的可以区别两个反射点(即不同物体或者同一物体的不同部分)的最小距离为0.5m，即，当两个反射点之间距离大于0.5m的认为该两个反射点是两个不同的物体或者同一物体的不同部分，当两个反射点之间距离小于或等于0.5m的认为这两个物体是属于同一个物体或者同一物体的同一部分。因此，当两个反射点对应的两个回波时间间隔大于预设第一时间间隔，即0.5m÷3*108cm/s＝1.67ns时，则认为是该两个反射点属于两个不同物体或者同一物体的不同部分。
步骤S502：计算n份子回波信号中每一份子回波信号的子反射率。
具体地，反射率计算装置利用系统响应计算反射率的方法主要是使用雷达方程进行反演，再利用进行反演后的方程计算所述n份子回波信号中每一份子回波信号的子反射率。例如：可以将n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值代入子反射率计算公式，计算所述n份子回波信号中每一份子回波信号的子反射率。
在一种可能实现的方式中，反射率计算装置计算所述n份子回波信号中每一份子回波信号的子反射率之前，还需要确定所述n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；其中计算所述n份子回波信号中每一份子回波信号的子反射率，包括：根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率。可以理解的是，子回波信号对应的冲激响应能够直观的表现出发射信号在某一时刻目标物反射回的信号强度，冲激响应不同的延时代表了目标物与接收端之间距离的差别，而且子回波信号对应的冲激响应个数也代表了反射信号能量所分配份数，因此，利用目标物的冲激响应计算反射率的方法可以在实时处理系统中，简单精确的计算物体的反射率。
可选的，反射率计算装置根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算n份子回波信号中每一份子回波信号的子反射率，包括：根据激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积，确定第一比值；将n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与第一比值分别相乘后累 加，获得n份子回波信号中每一份子回波信号的子反射率。可以理解的是，首先根据激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积等，确定第一比值，因为第一比值可以代表反射的回波信号在大气和接收端等中受到的影响，所以再将该第一比值与代表接收信号与发射信号比值的冲激响应值相乘后累加计算获得的n份子回波信号中每一份子回波信号的子反射率可以更加精确，其中，冲激响应值为冲激响应的幅度值。这种利用激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积与目标物的冲激响应计算反射率的方法可以在实际生活的实时处理系统中，简单精确的计算物体的反射率。
可选的，反射率计算装置根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算n份子回波信号中每一份子回波信号的子反射率包括：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算n份子回波信号中每一份子回波信号的子反射率，其中，子反射率计算公式可以为：
Figure PCTCN2019105439-appb-000015
其中，ρ i为所述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为所述接收端的有效接收面积，θ为所述发射端的发射光学系统光轴与目标法向ON的夹角，R ij为第i份子回波信号中第j个冲激响应对应的目标物与所述接收端之间的距离，
Figure PCTCN2019105439-appb-000016
为所述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、5……n，j为大于或等于1的正整数，且j小于或等于回波信号对应的冲激响应的个数。其中，需要说明的是，冲激响应值h ij是指冲激响应的幅度值，R ij可以根据光速c以及发射端发射信号被发出的时间与回波信号到达接收端时间之间的时间间隔，计算得出第i份子回波信号中第j个冲激响应对应的目标物与所述接收端之间的距离，反射率计算公式是利用雷达方程反演出的反射率计算公式，本申请实施例在计算第i份子回波信号的子反射率时，将
Figure PCTCN2019105439-appb-000017
视为一个冲激响应的冲激响应的幅度值，用于代表发射信号在某一时刻目标物反射回的信号强度，因此可以根据第i份子回波信号中第j个冲激响应对应的冲激响应值获得的第i份子回波信号对应目标物的反射率信息，降低了反射率的计算难度。其中，需要说明的是，若n份子回波信号无法进行响应估计时，可以截取出满足条件(例如：满足距离间隔τ的子回波信号中最大的n个拐点附近且小于发射信号两倍脉宽)的幅值，通过幅值带入子反射率计算公式计算n份子回波信号的子反射率，其中，
Figure PCTCN2019105439-appb-000018
可视为n份子回波信号的一份子回波信号中第j个的满足上述条件的幅值f j。可以理解的是，本申请中计算反射率大小时，所获得的冲激响应值是指冲激响应幅度值。
步骤S503：将n份子回波信号的子反射率累加获得目标物的反射率。
具体地，反射率计算装置将n份子反射率累加获得目标物的反射率。其中，物体的反 射回的能量可以视为是固定的一份，然后将一整份反射回的能量分为n小份后再累加，仍然可以得到完整的一份能量，因此，反射率计算装置可以从接收端接收的目标物反射的回波信号中提取n份子回波信号，将n份子回波信号的子反射率累加后获得目标区域的物体或目标物的反射率。可选的，得到与回波强度强相关的反射率信息后，还可以进一步对反射率再次进行修正或标定以得到更加精确的反射率信息。可以理解的是，以该方法得到的反射率时目标区域的物体或目标物的平均反射率。
请参考附图5E，图5E是本申请实施例提供的一种目标物的反射率计算方法与上述方案二中一种基于强度反演的反射率计算方法的计算结果对比表，本申请实施例从系统响应的角度出发，将发射信号所经历的过程当做一个系统，利用系统的整体响应逐步去耦合，然后进行反演的方法进行反射率估计。即，根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值和子反射率计算公式计算所述n份子回波信号中每一份子回波信号的子反射率，使用目标响应估计方法可以将反射率估计的误差限制在一个比较小的范围内，有效解决目标物形状、入射角等引起的反射率估计模糊问题，相比单峰值点估计或峰值叠加的方法有明显提升。图5E展示了上述两种反射率估计方法的均值与标准差，相较于目标物体真实的反射率0.1，本申请实施例计算的反射率为0.0961，标准差为0.000417，相较于真实反射率的最大偏差小于7％；而上述方案二提供的一种基于强度反演的反射率计算方法，计算的反射率单峰值点时为0.0726，标准差为0.0093，相较于真实反射率的最小偏差还大于15％，可以看出本申请实施例提供的目标物响应估计的方法具有明显的优势。需要说明的是，上述结果只是在某一场景下的效果示意表，不代表全部场景的情况。
可选的，根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，所述反射率计算公式为
Figure PCTCN2019105439-appb-000019
ρ i为所述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、5……n。可以理解的是，将一个整体分为n份后再累加，而且在计算其中一份时不需要得知入射角、粗糙度等信息，模型简单而且不需要进行标定，能较好地适用于实时处理系统中，简单精确的计算物体的反射率。
基于上述实施例的相关描述，可以理解的是，在计算目标物体(例如：目标区域内的一个或多个物体)的反射率时，由于目标物体的几何形状不规则(例如：目标物体拥有多个不同角度的表面)，可能会导致发射信号照射在物体不同表面上时的入射角不同，进而导致目标物体的反射率计算结果不同；而且，若目标物体为目标区域内多个物体时，由于多个目标物体的位置可能是在很相近的地点，距离接收端的距离很远，所以多个目标物体也可能会被视为一个几何形状不规则的物体。所以考虑到目标区域内的物体可能由多个不同的物体组成，或者目标物体也可能是一种形状不规则的物体，通过上述图5A所提供的方法，反射率计算装置可以在接收端接收的目标物体的回波信号中提取出n份子回波信号后，再计算n份子回波信号中每一份子回波信号的子反射率，最后将n份子反射率累加获得目标区域内物体或者目标物的反射率。其中，因为同一个目标物体的同一部分拥有相同或相似的材质、入射角以及与接收端之间的距离，所以被该部分反射回接收端的信号都是相似且时间间隔相近的信号。假若，目标物有两个不同距离的两个部位，即使该两个部位拥有相同的材质和形状，只要距离接收端之间的距离不同，则到达接收端的时间也就不同，进而该两个部位反射回接收端的信号的时间间隔大于预设第一时间间隔，因此，不能认为该 两个部位是同一个目标物的同一部分。因此，若接收端接收从目标物反射回的任意两个回波的时间在预设第一时间间隔内时，则可以认为该两个回波可以属于同一个目标物的同一部分反射回接收端的子回波信号，其中，预设第一时间间隔为目标物上、距离大于或者等于预设距离阈值的两个反射点反射的回波信号到达接收端的时间间隔，目标物可以为一个目标物体或者目标区域内多个物体。进一步的，本申请实施例可以按照上述规则从接收端接收的目标物反射的回波信号中提取出n份子回波信号，可以理解的是，一份子回波信号代表一个物体或一个物体的某一部分，这种从系统响应的角度出发，将发射信号所经历的过程当做一个系统，利用系统的整体响应逐步去耦合，然后进行反演的方法进行反射率计算的方法，与现有技术计算反射率的方法相比，可以将反射率估计的误差限制在一个比较小的范围内，有效解决目标物形状、入射角等引起的反射率估计模糊问题。其中，还需要说明的是，从接收端接收的目标物反射的回波信号中提取出的n份子回波信号可以是在回波信号中把符合条件的子回波信号全部提取出来，分为n份子回波信号，还可以是在符合条件的全部子回波信号中选择性的提取其中的n份信号为子回波信号，n为大于或等于1的正整数。因此，将回波信号提取n份子回波信号，计算n份子回波信号的子反射率后再累加获得整个目标物反射率的方法，避免了因发射信号受到入射角、目标物几何形状对计算目标物反射率的影响，而且方法简单，可以应用在实时处理系统中，简单精确的计算物体的反射率，提高了反射率的计算精度和效率。
参见图6，图6是本申请实施例提供的另一种目标物的反射率计算方法的流程示意图，该方法可应用于上述图4中所述的激光雷达中，其中的激光雷达20可以用于支持并执行图6中所示的方法流程步骤S601-步骤S605。
步骤S601：通过最小二乘法或最小均方差法对回波信号进行响应估计，获得回波信号对应的m个冲激响应。
具体地，目标物响应估计可以通过最小二乘法，最小均方误差等方法，对反射信号进行估计。即反射率计算装置可以通过最小二乘法或最小均方差法对所述回波信号进行响应估计，获得所述回波信号对应的m个冲激响应，该m个冲激响应可以与发射信号卷积后得到反射回接收端的回波信号。在本申请实施例中，满足一定的距离间隔τ的回波或者满足到达接收端时间间隔的回波为不同的回波，在每个回波附近选取满足一定条件(例如：该条件可以包括但不限于一定持续时间、一段采样点、一定相关系数门限等)的冲激响应进行后续去耦合。
可选的，通过最小二乘法对回波信号进行响应估计，获得回波信号对应的m个冲激响应，可以包括：接收信号y可以表示为发射信号x与冲激响应h的卷积加上系统噪声，即：y＝x*h+n，那么在频域上可以表示为：Y＝XH+W，最小二乘法所估计的冲激响应需要令接收端的回波信号与无高斯白噪声时的回波信号之差的平方达到最小，即满足:
Figure PCTCN2019105439-appb-000020
那么：
Figure PCTCN2019105439-appb-000021
令
Figure PCTCN2019105439-appb-000022
计算得出：
Figure PCTCN2019105439-appb-000023
因此，冲激响应
Figure PCTCN2019105439-appb-000024
容易理解的是，在忽略系统噪声的情况下，通过最小二乘法，可以使m个冲激响应可以直接通过发射信号x和回波信号y做反卷积得到，该方法包括但不限于频域相除、构建离散傅里叶变换逆变换矩阵等。在系统存在噪声时，最小二乘法估计出来的系统响应会有偏差，此时，可以通过包括但不限于MMSE、维纳滤波等方法在最大程度保持估计响应的幅度、延时不变的情况下去除噪声。
步骤S602：根据m个冲激响应确定z个冲激响应集合；去除z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合。
具体地，反射率计算装置可以根据所述m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，所述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，z为大于或等于n的正整数，且m为大于或等于z的正整数；去除所述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，所述n个冲激响应集合与所述n份子回波信号一一对应，且包括所述n份子回波信号对应的冲激响应。准确地从多个目标物或者不规则几何形状的目标中中，确定出来自于同一个目标物或者一个目标物相同部分的回波，进而避免后续在反射率的计算过程中目标物几何形状、或不同目标物反射率等因素影响，提高了反射率的计算精度。
步骤S603：根据m个冲激响应，计算n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值。
具体地，反射率计算装置在提取n份子回波信号前，可以将回波信号由时域信号转变为频域信号的冲激响应，该冲激响应可以与发射信号卷积后得到反射回接收端的回波信号，因此，回波信号对应的冲激响应能够直观的表现出发射信号在某一时刻目标物反射回的信号强度，即子回波信号对应的一个或多个冲激响应的冲激响应值，可以表示在某一时刻由该子回波信号代表的目标物将发射信号反射回接收端的信号强度。又因为，物体的反射率是投射到物体上面被反射的辐射能与投射到物体上的总辐射能之比，所以可以在实时处理系统中，可以直接利用子回波信号对应的一个或多个冲激响应的冲激响应值，计算对应的子回波信号的子反射率，进而确定整个目标物的反射率，这种简单精确的计算方式，有效解决反射率计算中的目标物形状、入射角引起的模糊问题，不仅提高了反射率的计算精度和效率，还可以更直观的区分出不同物体反射率的区别。例如：冲激响应值越大的物体，其反射率也越大，需要说明的是，本申请实施例中的冲激响应值是指冲激响应的幅度值。
在一种可能实现的方式中，所述n份子回波信号中每一份子回波信号中所有冲激响应 的冲激响应值为去除所述接收端、信道和发射端中的一个或多个影响因素后的冲激响应幅度值，所述影响因素包括损耗、滤波、衰减中的一种或多种。因为回波信号在接收端接收后，需要通过探测器进行模数转换，再经过处理器对转换后的信号进行处理的过程中，一方面会受到处理过程中的发射端、接收端或探测器等器件(例如：接收机、雪崩光电二极管、跨阻放大器、低通滤波器、模拟数字转换器等)的损耗、滤波或衰减的影响，另一方面由于接收端的效率、损耗也会给信号带来变化。因此，在计算子反射率之前，需要将这些影响因素进行去耦合，再将去除影响后的冲激响应的幅度值代入公式计算，能够得到更加精准的反射率结果。可以理解的是，去耦合的方法包括但不限于实际标定、器件与系统建模或二者的结合等。如果将信号发出之后直到回波信号进入数字信号处理之前，激励(发射信号)所经历的整个过程当做一个系统的话，发射信号在传输过程中，系统的响应包括发射端、信道、目标物以及接收端等至少四部分的响应。根据发射与接收信号估计出的响应包含了以上几部分，因此，需要对与目标物响应无关的部分进行去耦合，以得到仅与目标物相关的回波信号，使得目标物的反射率计算更加精确。
其中，可选的，反射率计算过程中可以将接收端影响因素去耦合。在回波信号从接收到探测器到信号处理端，一方面会受到APD、TIA、ADC等器件的损耗、滤波影响，另一方面接收机效率、插损也会给信号带来变化。因此，在响应的去模糊中，需要将这些影响因素进行去耦合。去耦合的方法包括但不限于实际标定、器件与系统建模或二者的结合。在一种可能实现的方式中，实际标定的方法步骤如下：在实际系统中，在接收端使用不同波形的信号作为接收端可能接收到的信号，这里的不同波形包括但不限于不同脉宽、不同幅度、不同包络形状等。输入这些不同波形的信号后，采集信号处理端输出后的波形并与输入信号一一对应。这样可以得到接收端系统的输入与输出信号，从而可以对接收端对不同信号的响应进行估计，建立对应的模型或查找表。之后，在实时处理中，通过LiDAR接收到的信号可以通过已经建立的接收端系统模型或查找表，获得接收端对信号的影响，然后将这种影响通过包括但不限于反卷积等方法去除。在一种可能实现的方式中，器件与系统建模的步骤如下：在接收端系统中，对APD、TIA、ADC等器件进行建模，分别对每个器件对使用不同波形的信号的影响或响应进行分析，这里的不同波形包括但不限于不同脉宽、不同幅度、不同包络形状等。根据分立器件对信号影响或响应的累加得到接收端整个系统的响应。然后在实时系统中，通过LiDAR接收到的信号可以通过已经建立的接收端系统模型或查找表，获得接收端对信号的影响，然后将这种影响通过包括但不限于反卷积等方法去除。
可选的，反射率计算过程中可以将信道影响因素去耦合。信号的传输过程中，受到的大气衰减、几何损耗等影响，在一定程度上影响系统的幅频响应。此外，如果得知此时的入射角，可以对该影响因素去模糊。信道影响去耦合的方法包括但不限于系统建模、实际标定或二者的结合。对信道影响去耦合的方法与上述接收端去耦合的方法基本相同，区别是信道影响去耦合在系统建模方法中，因为大气信道的每部分影响(即：在传输过程中多种类型的损耗)对信号是共同作用的，而不是上述接收端去耦合的方法中的分立影响。因此，系统建模的方法是将整个信道作为整体，同时考虑损耗、大气散射等影响进行建模与影响去耦合。之后，在实时处理中，通过LiDAR接收到的信号可以通过已经建立的信道损 耗模型或查找表，获得接收端对信号的影响，然后将这种影响也可以通过包括但不限于反卷积等方法去除。
可选的，反射率计算过程中可以将发射端影响因素去耦合。在发射端，发射信号的波形、幅度尽管可以通过系统设计可以较为准确的得到，但具体到实际LiDAR系统又会有不同的差别，包括但不限于放大器、扫描器、光学器件等。因此，在发射端，也需要对这些影响进行去耦合，方法包括但不限于系统建模、实际标定或二者的结合。对该部分系统响应估计与去耦合的方法与上述接收端去耦合的方法基本相同，系统与器件建模方法中，不同发射端器件也是分立影响。区别是在发射端影响因素去耦合的系统标定中，若无法直接从发射端接收到所有的发射信号，则需要通过一定距离信道才能接收到所有的发射信号，可以通过简单建模方法将几何损耗等信道影响降至最低后，再对接收到所有的发射信号的影响因素去耦合。该方法采用响应估计的方法，可以在系统无关因素解耦和后，准确估计单次回波对应的目标物反射率信息，可用于实时性要求较高的车载激光雷达中。
综上所述，反射率计算过程中将发射端、信道、以及接收端三部分的影响因素去耦合，因此，反射率计算装置计算的回波信号中只包含有目标物的影响，进而可以更加精确的计算目标物体的反射率。
步骤S604：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率。
步骤S605：将n份子回波信号的子反射率累加获得目标物的反射率。
具体地，步骤S604-步骤S605的相关描述可以参考上述图5A中步骤S502-步骤S503的相关描述，此处不再赘述。
在本申请实施例中，回波信号对应的冲激响应能够直观的表现出发射信号在某一时刻目标物反射回的信号强度，即子回波信号对应的一个或多个冲激响应的冲激响应值，可以表示在某一时刻由该子回波信号代表的目标物将发射信号反射回接收端的信号强度，因此，在提取n份子回波信号前，可以将回波信号由时域信号转变为频域信号的冲激响应。又因为，物体的反射率是投射到物体上面被反射的辐射能与投射到物体上的总辐射能之比，所以在实时处理系统中，可以利用子回波信号对应的一个或多个冲激响应的冲激响应值，计算对应的子回波信号的子反射率，进而确定目标物体的反射率，这种利用冲激响应反演得到反射率的计算方式，可以有效解决反射率计算中因目标物的几何形状、发射信号的入射角引起的反射率计算模糊的问题，本申请实施例不仅提高了反射率的计算精度和效率，还可以利用子回波信号不同的冲激响应值，更直观的区分出不同物体反射率。例如：冲激响应值越大的物体，其反射率也越大。
不难理解的是，本申请实施不仅仅能应用于激光雷达中，还能应用于例如：“线发线收”“面发面收”、“点发点收”等雷达系统中，雷达系统中对反射率计算带来偏差的部分包括发射与接收端器件、信道影响、目标物特性等。在实际的雷达系统应用中，发射端与接收端器件可以通过实际标定或者器件建模等方法进行影响因素去耦合，信道影响也可以通过建模等方法进行去除。但是目标物特性如形状、材质以及由其形状引起的入射角变化等都会对回波强度与反射率计算带来非常大的偏差，并且该影响的实时去模糊是一个难点。本 申请实施例，从系统响应的角度出发，将发射信号所经历的过程当做一个系统，利用系统的整体响应逐步影响因素去耦合，然后通过雷达方程反演的方法进行反射率计算，相比单峰值点估计或峰值叠加的方法有明显提升。
需要说明的是，由于n个子回波信号的子反射率分别对应目标区域内不同物体或者物体的不同部分，所以本申请中的反射率计算方法除了可应用于激光雷达的计算反射率的场景，还以用于通过该计算得到的反射率确定目标区域内物体的数量、材质、种类等实时监测的场景中。例如：实时车载系统通过反射率的监控识别路边的行车标志，行人，障碍物等。更进一步的，还可应用于智能交通、自动驾驶、大气环境监测、地理测绘、无人机侦查等领域。更广泛的，任何需要计算反射率的场景，都可以适用本申请提供的方案。该方法可适用于“线发线收”“面发面收”、“点发点收”等激光雷达系统中。
上述详细阐述了本申请实施例的方法，下面提供了本申请实施例的相关装置。
请参见图7，图7是本申请实施例提供的一种目标物的反射率计算装置的结构示意图，该目标物的反射率计算装置10可以包括提取单元701、子反射率单元702和反射率单元703，还可以包括：响应估计单元704、第一确定单元705和第二确定单元706其中，各个单元的详细描述如下：
提取单元701，用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，所述n份子回波信号中的每相邻两份子回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数。
子反射率单元702，用于计算所述n份子回波信号中每一份子回波信号的子反射率。
反射率单元703，用于将n份子回波信号的子反射率累加获得目标物的反射率。
在一种可能实现的方式中，n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。
在一种可能实现的方式中，所述装置还包括：响应估计单元704，用于在从接收端接收的目标物反射的回波信号中提取出n份子回波信号之前，通过最小二乘法或最小均方差法对所述回波信号进行响应估计，获得所述回波信号对应的m个冲激响应，m为大于或等于1的正整数；第一确定单元705，用于在从接收端接收的目标物反射的回波信号中提取出n份子回波信号之后，根据m个冲激响应，计算n份子回波信号中每一份子回波信号对应的一个或多个冲激响应的冲激响应值；计算n份子回波信号中每一份子回波信号的子反射率包括：根据每一份子回波信号对应的一个或多个冲激响应的冲激响应值计算对应的子回波信号的子反射率。
在一种可能实现的方式中，所述提取单元701具体用于：根据所述m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，所述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，所述预设第二时间间隔为小于预设第一时间间隔的预设时间间隔，z为大于或等于n的正整数，且m为大于或等于z的正整数；去除所述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，所述n个冲激响应集合与所述n份子回波信号一一对应，且包括所述n份子回波信 号对应的冲激响应。
在一种可能实现的方式中，所述提取单元701具体用于：根据所述回波信号确定k个信号集合，其中，每一个信号集合中包括的多个回波中的每相邻两个回波到达所述接收端的时间间隔在预设第三时间间隔内，所述k个信号集合中任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；确定所述k个信号集合的每一个信号集合中所有回波的幅度门限；去除所述k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，所述n个信号集合与所述n份子回波信号一一对应。
在一种可能实现的方式中，所述装置还包括：第二确定单元706，用于在所述计算所述n份子回波信号中每一份子回波信号的子反射率之前，确定所述n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；所述子反射率单元702具体用于：根据上述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算上述n份子回波信号中每一份子回波信号的子反射率。
在一种可能实现的方式中，上述子反射率单元702具体用于：根据激光在大气中的单程透射率、接收光学系统的效率、接收端的有效接收面积，确定第一比值；将n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与第一比值分别相乘后累加，获得n份子回波信号中每一份子回波信号的子反射率。
在一种可能实现的方式中，上述子反射率单元702具体用于：根据n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算n份子回波信号中每一份子回波信号的子反射率，其中，子反射率计算公式为：
Figure PCTCN2019105439-appb-000025
Figure PCTCN2019105439-appb-000026
其中，ρ i为所述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为所述接收端的有效接收面积，θ为所述发射端的发射光学系统光轴与目标法向ON的夹角，R ij为第i份子回波信号中第j个冲激响应对应的目标物与所述接收端之间的距离，
Figure PCTCN2019105439-appb-000027
为所述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、3……n，j为大于或等于1的正整数。
在一种可能实现的方式中，所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值为去除所述接收端、信道和发射端中的一个或多个影响因素后的冲激响应值，所述影响因素包括损耗、滤波、衰减中的一种或多种。
在一种可能实现的方式中，所述反射率单元703具体用于：根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，所述反射率计算公式为
Figure PCTCN2019105439-appb-000028
ρ i为所述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、3……n。
在一种可能实现的方式中，上述预设第一时间间隔为所述目标物上、距离大于或者等于预设距离阈值的两个反射点分别反射的两个回波信号到达接收端的时间间隔。
需要说明的是，本申请实施例中所描述的目标物的反射率计算装置10中各功能单元的 功能可参见上述图5A-图6中所述的方法实施例的相关描述，此处不再赘述。
如图8所示，图8是本申请实施例提供的另一种目标物的反射率计算装置的结构示意图，该装置20包括至少一个处理器201，至少一个存储器202、至少一个通信接口203。此外，该设备还可以包括天线等通用部件，在此不再详述。
处理器201可以是通用中央处理器(CPU)，微处理器，特定应用集成电路(application-specific integrated circuit，ASIC)，或一个或多个用于控制以上方案程序执行的集成电路。
通信接口203，用于与其他设备或通信网络通信，如以太网，无线接入网(RAN)，核心网，无线局域网(Wireless Local Area Networks，WLAN)等。
存储器202可以是只读存储器(read-only memory，ROM)或可存储静态信息和指令的其他类型的静态存储设备，随机存取存储器(random access memory，RAM)或者可存储信息和指令的其他类型的动态存储设备，也可以是电可擦可编程只读存储器(Electrically Erasable Programmable Read-Only Memory，EEPROM)、只读光盘(Compact Disc Read-Only Memory，CD-ROM)或其他光盘存储、光碟存储(包括压缩光碟、激光碟、光碟、数字通用光碟、蓝光光碟等)、磁盘存储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质，但不限于此。存储器可以是独立存在，通过总线与处理器相连接。存储器也可以和处理器集成在一起。
其中，所述存储器202用于存储执行以上方案的应用程序代码，并由处理器201来控制执行。所述处理器201用于执行所述存储器202中存储的应用程序代码。
存储器202存储的代码可执行以上图5A提供的反射率计算方法，比如从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，n份子回波信号中的每相邻两份子回波信号到达接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；计算n份子回波信号中每一份子回波信号的子反射率；将n份子回波信号的子反射率累加获得目标物的反射率。
需要说明的是，本申请实施例中所描述的目标物的反射率计算装置20中各功能单元的功能可参见上述图5A-图6中所述的方法实施例的相关描述，此处不再赘述。
在上述实施例中，对各个实施例的描述都各有侧重，某个实施例中没有详述的部分，可以参见其他实施例的相关描述。
需要说明的是，对于前述的各方法实施例，为了简单描述，故将其都表述为一系列的动作组合，但是本领域技术人员应该知悉，本申请并不受所描述的动作顺序的限制，因为依据本申请，某些步骤可能可以采用其他顺序或者同时进行。其次，本领域技术人员也应该知悉，说明书中所描述的实施例均属于优选实施例，所涉及的动作和模块并不一定是本申请所必须的。
在本申请所提供的几个实施例中，应该理解到，所揭露的装置，可通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如上述单元的划分，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 以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性或其它的形式。
上述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
上述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以为个人计算机、服务端或者网络设备等，具体可以是计算机设备中的处理器)执行本申请各个实施例上述方法的全部或部分步骤。其中，而前述的存储介质可包括：U盘、移动硬盘、磁碟、光盘、只读存储器(Read-Only Memory，缩写：ROM)或者随机存取存储器(Random Access Memory，缩写：RAM)等各种可以存储程序代码的介质。
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：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；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (26)

  1. 一种目标物的反射率计算方法，其特征在于，包括：
    从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，所述n份子回波信号中的每相邻两份子回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；
    计算所述n份子回波信号中每一份子回波信号的子反射率；
    将所述n份子回波信号的子反射率累加获得所述目标物的反射率。
  2. 根据权利要求1所述方法，其特征在于，所述n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。
  3. 根据权利要求1或2所述方法，其特征在于，所述从接收端接收的目标物反射的回波信号中提取出n份子回波信号之前，所述方法还包括：
    通过最小二乘法或最小均方差法对所述回波信号进行响应估计，获得所述回波信号对应的m个冲激响应，m为大于或等于1的正整数；
    所述从接收端接收的目标物反射的回波信号中提取出n份子回波信号之后，还包括：
    根据所述m个冲激响应，计算所述n份子回波信号中每一份子回波信号对应的一个或多个冲激响应的冲激响应值；
    所述计算所述n份子回波信号中每一份子回波信号的子反射率包括：
    根据所述每一份子回波信号对应的一个或多个冲激响应的冲激响应值计算对应的子回波信号的子反射率。
  4. 根据权利要求3所述方法，其特征在于，所述从接收端接收的目标物反射的回波信号中提取出n份子回波信号，包括：
    根据所述m个冲激响应确定z个冲激响应集合，其中，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，所述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，所述预设第二时间间隔为小于所述预设第一时间间隔的预设时间间隔，z为大于或等于n的正整数，且m为大于或等于z的正整数；
    去除所述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，所述n个冲激响应集合与所述n份子回波信号一一对应，且包括所述n份子回波信号对应的冲激响应。
  5. 根据权利要求1或2所述方法，其特征在于，所述从接收端接收的目标物反射的回波信号中提取出n份子回波信号，包括：
    根据所述回波信号确定k个信号集合，其中，每一个信号集合中包括的多个回波中的每相邻两个回波到达所述接收端的时间间隔在预设第三时间间隔内，所述k个信号集合中 任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；
    确定所述k个信号集合的每一个信号集合中所有回波的幅度门限；
    去除所述k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，所述n个信号集合与所述n份子回波信号一一对应。
  6. 根据权利要求5所述方法，其特征在于，所述计算所述n份子回波信号中每一份子回波信号的子反射率之前，还包括：
    确定所述n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；
    所述计算所述n份子回波信号中每一份子回波信号的子反射率，包括：
    根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率。
  7. 根据权利要求6所述方法，其特征在于，所述根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率，包括：
    根据激光在大气中的单程透射率、接收光学系统的效率、所述接收端的有效接收面积，确定第一比值；
    将所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与所述第一比值分别相乘后累加，获得所述n份子回波信号中每一份子回波信号的子反射率。
  8. 根据权利要求6所述方法，其特征在于，所述根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率包括：
    根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算所述n份子回波信号中每一份子回波信号的子反射率，其中，所述子反射率计算公式为：
    Figure PCTCN2019105439-appb-100001
    其中，ρ i为所述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为所述接收端的有效接收面积，θ为所述发射端的发射光学系统光轴与目标法向ON的夹角，R ij为第i份子回波信号中第j个冲激响应对应的目标物与所述接收端之间的距离，
    Figure PCTCN2019105439-appb-100002
    为所述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、3……n，j为大于或等于1的正整数。
  9. 根据权利要求6所述方法，其特征在于，所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值为去除所述接收端、信道和发射端中的一个或多个影响因素 后的冲激响应值，所述影响因素包括损耗、滤波、衰减中的一种或多种。
  10. 根据权利要求1-9所述任意一项方法，其特征在于，所述将n份子反射率累加获得目标物的反射率，包括：
    根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，所述反射率计算公式为
    Figure PCTCN2019105439-appb-100003
    ρ i为所述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、3……n。
  11. 根据权利要求1-10所述任意一项方法，其特征在于，所述预设第一时间间隔为所述目标物上、距离大于或者等于预设距离阈值的两个反射点分别反射的两个所述回波信号到达所述接收端的时间间隔。
  12. 一种激光雷达，其特征在于，包括：接收端和处理器；其中，
    所述接收端，用于接收目标物反射的回波信号；
    所述处理器，用于：
    从接收端接收的目标物反射的回波信号中提取出n份子回波信号，其中，所述n份子回波信号中的每相邻两份子回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；
    计算所述n份子回波信号中每一份子回波信号的子反射率；
    将所述n份子回波信号的子反射率累加获得所述目标物的反射率。
  13. 根据权利要求12所述激光雷达，其特征在于，所述接收端，具体用于接收所述目标物的模拟回波信号；所述激光雷达还包括探测器，所述接收端、所述处理器分别与所述探测器耦合；
    所述探测器，用于将所述接收端接收的所述模拟回波信号进行模数转换，并将进行模数转换后的回波信号发送给所述处理器；
    所述处理器，具体用于：
    从所述进行模数转换后的回波信号中提取出n份子回波信号，其中，所述n份子回波信号中的每相邻两份子回波信号对应的模拟回波信号到达所述接收端的时间间隔大于预设第一时间间隔，n为大于或等于1的正整数；
    计算所述n份子回波信号中每一份子回波信号的子反射率；
    将所述n份子回波信号的子反射率累加获得所述目标物的反射率。
  14. 根据权利要求12或13所述激光雷达，其特征在于，所述n份子回波信号中的每一份子回波信号的信号强度大于信号强度阈值。
  15. 根据权利要求14所述激光雷达，其特征在于，所述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号之前，所述处理器还用于：
    通过最小二乘法或最小均方差法对所述回波信号进行响应估计，获得所述回波信号对应的m个冲激响应，m为大于或等于1的正整数；
    所述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号之后，所述处理器还用于：
    根据所述m个冲激响应，计算所述n份子回波信号中每一份子回波信号对应的一个或多个冲激响应的冲激响应值；
    所述计算所述n份子回波信号中每一份子回波信号的子反射率包括：
    根据所述每一份子回波信号对应的一个或多个冲激响应的冲激响应值计算对应的子回波信号的子反射率。
  16. 根据权利要求15所述激光雷达，其特征在于，所述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号时，所述处理器具体用于：
    根据所述m个冲激响应确定z个冲激响应集合，每一个冲激响应集合中包括的多个冲激响应中的任意相邻两个冲激响应之间的时间间隔在预设第二时间间隔内，所述预设第二时间间隔为小于所述预设第一时间间隔的预设时间间隔，所述z个冲激响应集合中任意两个冲激响应集合之间的交集为空集，z为大于或等于n的正整数，且m为大于或等于z的正整数；
    去除所述z个冲激响应集合的每一个冲激响应集合中冲激响应值小于响应阈值的冲激响应后，获得n个冲激响应集合，所述n个冲激响应集合与所述n份子回波信号一一对应，且包括所述n份子回波信号对应的冲激响应。
  17. 根据权利要求14所述激光雷达，其特征在于，所述处理器用于从接收端接收的目标物反射的回波信号中提取出n份子回波信号时，所述处理器具体用于：
    根据所述回波信号确定k个信号集合，每一个信号集合中包括的多个回波中的每相邻两个回波到达所述接收端的时间间隔在预设第三时间间隔内，所述k个信号集合中任意两个信号集合之间的交集为空集，k为大于或等于n的正整数；
    确定所述k个信号集合的每一个信号集合中所有回波的幅度门限；
    去除所述k个信号集合的每一个信号集合中所有幅度门限小于预设幅度门限阈值的回波后，获得n个信号集合，所述n个信号集合与所述n份子回波信号一一对应。
  18. 根据权利要求17所述激光雷达，其特征在于，所述处理器用于计算所述n份子回波信号中每一份子回波信号的子反射率之前，所述处理器还用于：
    确定所述n份子回波信号中每一份子回波信号中对应的所有冲激响应的冲激响应值；
    所述处理器用于计算所述n份子回波信号中每一份子回波信号的子反射率时，所述处理器具体用于：根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率。
  19. 根据权利要求18所述激光雷达，其特征在于，所述处理器用于根据所述n份子回 波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率时，所述处理器具体用于：
    根据激光在大气中的单程透射率、接收光学系统的效率、所述接收端的有效接收面积确定第一比值；
    将所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值与所述第一比值分别相乘后累加，获得所述n份子回波信号中每一份子回波信号的子反射率。
  20. 根据权利要求18所述激光雷达，其特征在于，所述处理器用于根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值，计算所述n份子回波信号中每一份子回波信号的子反射率时，所述处理器具体用于：根据所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值通过子反射率计算公式，计算所述n份子回波信号中每一份子回波信号的子反射率，其中，所述所述子反射率计算公式为：ρ i＝
    Figure PCTCN2019105439-appb-100004
    其中，ρ i为所述n份子回波信号中第i份子回波信号的子反射率，τ a为激光在大气中的单程透射率，η r为接收光学系统的效率，A r为所述接收端的有效接收面积，θ为所述发射端的发射光学系统光轴与目标法向ON的夹角，R ij为第i份子回波信号中第j个冲激响应对应的目标物与所述接收端之间的距离，
    Figure PCTCN2019105439-appb-100005
    为所述n份子回波信号中第i份子回波信号中第j个冲激响应对应的冲激响应值，P Rij为第i份子回波信号中第j个冲激响应对应的激光接收功率，P Tij为第i份子回波信号中第j个冲激响应对应的激光发射功率，i＝1、2、3……n，j为大于或等于1的正整数。
  21. 根据权利要求18所述激光雷达，其特征在于，所述n份子回波信号中每一份子回波信号中所有冲激响应的冲激响应值为去除所述接收端、信道和发射端中的一个或多个影响因素后的冲激响应值，所述影响因素包括损耗、滤波、衰减中的一种或多种。
  22. 根据权利要求12-21所述任意一种激光雷达，其特征在于，所述处理器用于将n份子反射率累加获得目标物的反射率时，所述处理器具体用于：
    根据反射率计算公式，将n份子反射率累加获得目标物的反射率，其中，所述反射率计算公式为
    Figure PCTCN2019105439-appb-100006
    ρ i为所述n份子回波信号中第i份子回波信号的子反射率，i＝1、2、3……n。
  23. 根据权利要求12-22所述任意一种激光雷达，其特征在于，所述预设第一时间间隔为所述目标物上、距离大于或者等于预设距离阈值的两个反射点分别反射的两个所述回波信号到达所述接收端的时间间隔。
  24. 一种芯片系统，其特征在于，所述芯片系统包括至少一个处理器，存储器和接口电路，所述存储器、所述接口电路和所述至少一个处理器通过线路互联，所述至少一个存 储器中存储有指令；所述指令被所述处理器执行时，权利要求1-11中任意一项所述的方法得以实现。
  25. 一种计算机存储介质，其特征在于，所述计算机存储介质存储有计算机程序，该计算机程序被处理器执行时实现上述权利要求1-11任意一项所述的方法。
  26. 一种计算机程序，其特征在于，所述计算机程序包括指令，当所述计算机程序被计算机执行时，使得所述计算机执行如权利要求1-11中任意一项所述的方法。
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