Receiving control method and device of laser radar and laser radar

Abstract

The embodiment of the invention discloses a receiving control method and device for a laser radar and the laser radar, and the method comprises the steps: firstly, determining an echo feature value of an echo signal in a response period, then determining a baseline voltage fluctuation quantity based on the echo feature value, determining a target sampling threshold value according to the baseline voltage fluctuation quantity and a sampling threshold value of the response period, and carrying out the calculation of the target sampling threshold value. And finally, adjusting the threshold value of the next response period according to the target sampling threshold value. According to the receiving control method, the sampling threshold value is compensated, the compensated target sampling threshold value is obtained, accurate sampling of echo signals is achieved, the distance measuring effect is improved, meanwhile, compared with fixed threshold value compensation, the receiving control method adjusts the sampling threshold value in real time based on the influence of the received echo signals on the baseline voltage, and the distance measuring accuracy is improved. Therefore, the adjusted sampling threshold value is consistent with the fluctuation trend of the baseline voltage, the target sampling threshold value is more matched with the echo signal, and the sampling accuracy is further improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of laser radar technology, and in particular, to a laser radar receiving control method and device, and a laser radar. Background Art

[0002] With the rapid development of LiDAR technology, LiDAR products are widely used in scenarios such as autonomous driving, vehicle-mounted LiDAR, and vehicle-road collaboration. LiDAR technology emits a beam of detection laser to the object being measured, and then receives the light signal reflected from the object being measured. By processing and analyzing the received light signal, the distance, direction, height, shape and other parameters of the object being measured can be obtained.

[0003] When receiving echo signals, the devices in the receiving circuit will cause baseline voltage fluctuations, and the relative position of the threshold used for detection sampling and the baseline voltage will change, making the lidar's sampling of echo signals inaccurate and the ranging effect poor. Summary of the invention

[0004] In view of this, some embodiments of the present invention provide a laser radar receiving control method, device and laser radar, which can adjust the sampling threshold in real time according to the received echo signal, achieve accurate sampling of the echo signal, and thus improve the ranging effect.

[0005] In a first aspect, an embodiment of the present invention provides a receiving control method of a laser radar, the method comprising:

[0006] Determine the echo characteristic value of the echo signal of the response period;

[0007] Determine a baseline voltage fluctuation amount based on the echo characteristic value;

[0008] Determine a target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period;

[0009] The threshold of the next response cycle is adjusted according to the target sampling threshold.

[0010] In a second aspect, an embodiment of the present invention provides a receiving control device for a laser radar, the receiving control device comprising:

[0011] A first determination module, used to determine an echo characteristic value of an echo signal of a response period;

[0012] A second determination module, configured to determine a baseline voltage fluctuation amount based on the echo characteristic value;

[0013] A third determination module, configured to determine a target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period;

[0014] An adjustment module is used to adjust the threshold of the next response cycle according to the target sampling threshold.

[0015] In a third aspect, an embodiment of the present invention provides a laser radar, including:

[0016] at least one processor;

[0017] A memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the laser radar receiving control method as described above.

[0018] In a fourth aspect, a computer-readable storage medium is provided in an embodiment of the present invention, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer device to execute the laser radar receiving control method as described above.

[0019] Beneficial effects of the embodiments of the present invention: Different from the prior art, the receiving control method of the laser radar provided by the embodiments of the present invention first determines the echo characteristic value of the echo signal of the response period, then determines the baseline voltage fluctuation amount based on the echo characteristic value, and then determines the target sampling threshold according to the baseline voltage fluctuation amount and the sampling threshold of the response period, and finally adjusts the threshold of the next response period according to the target sampling threshold. The receiving control method compensates the sampling threshold to obtain the compensated target sampling threshold, realizes accurate sampling of the echo signal, and improves the ranging effect. At the same time, compared with the fixed threshold compensation, the receiving control method adjusts the sampling threshold in real time based on the influence of the received echo signal on the baseline voltage. The adjusted sampling threshold is consistent with the fluctuation trend of the baseline voltage, so that the target sampling threshold is more matched with the echo signal, further improving the sampling accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 It is a schematic diagram of an application environment of a laser radar receiving control method provided by an embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of a laser radar provided by an embodiment of the present invention;

[0023] Figure 3 is a structural schematic diagram of a receiving device provided by an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of a scenario in which a detection module samples an echo signal provided by an embodiment of the present invention;

[0025] Figure 5 It is a flowchart of a receiving control method of a laser radar provided in an embodiment of the present invention;

[0026] Figure 6 yes Figure 5 Schematic diagram of the process of step S11;

[0027] Figure 7 yes Figure 5 Schematic diagram of the process of step S12;

[0028] Figure 8 is a schematic diagram of a receiving control device of a laser radar provided in an embodiment of the present invention;

[0029] Fig. 9 It is a structural schematic diagram of a laser radar provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, all within the scope of protection of the present invention. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order from the module division in the device or the flow chart. In addition, the words "first", "second", "third", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0033] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification and in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0034] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] See also Figure 1 , Figure 1 Schematic diagram of the application environment of a laser radar receiving control method provided by an embodiment of the present invention. Figure 1 As shown, the application scenario includes: a laser radar 101 and a vehicle 102. The laser radar 101 is installed on various vehicles 102 that need to detect the surrounding environment. The vehicle 102 can be, for example, a vehicle, a ship, an aircraft, etc.

[0036] Optionally, when the vehicle 102 is a vehicle, the laser radar 101 can be installed on the front, rear, roof, side of the vehicle or any other body position where the laser radar 101 can be fixed. It is understood that the laser radar 101 can also be fixed on other device structure platforms that are externally connected to the vehicle. It is understood that the external device structure platform can keep running synchronously with the vehicle when the vehicle is running.

[0037] In one or more embodiments of this specification, see Figure 2 , Figure 2 It is a structural schematic diagram of a laser radar 101 provided in an embodiment of the present invention, and the laser radar 101 includes a transmitting device 10, a receiving device 20 and a control device 30, wherein: the transmitting device 10 is used to transmit a laser transmitting signal, and the laser transmitting signal is transmitted to the object to be measured, and is reflected by the object to be measured, and a laser echo signal is returned; the receiving device 20 (also referred to as a receiving module) is used to receive the laser echo signal; the control device 30 is used to receive and process data related to the echo signal sent by the receiving device 20 and control the transmitting device 10 to transmit the laser transmitting signal.

[0038] See also Figure 3 , Figure 3 is a schematic diagram of the structure of a receiving device 20 provided in an embodiment of the present invention, such as Figure 3As shown, the receiving device 20 includes a photoelectric conversion module 21, a cascade amplifier module 22, a detection module 23 and a threshold processing module 24. Among them, the input end of the photoelectric conversion module 21 receives the laser echo signal, the output end of the photoelectric conversion module 21 is connected to the input end of the cascade amplifier module 22, and the photoelectric conversion module 21 is a receiving sensor for converting the laser echo signal into a pulse electrical signal, which can be a PIN type photodetector or an avalanche photodiode. Since the avalanche photodiode has an internal gain, the sensitivity of the photoelectric sensor can be greatly improved, so the photodetector is preferably an avalanche photodiode.

[0039] The cascade amplifier module 22 may include a multi-stage gain circuit for amplifying the input pulse electrical signal step by step to obtain a multi-stage amplified echo signal. The cascade amplifier module 22 may also include a transimpedance amplifier to convert the pulse electrical signal from current to voltage.

[0040] The output end of the cascade amplifier module 22 is connected to the first input end of the detection module 23, the echo signal after multi-stage amplification is transmitted to the first input end of the detection module 23, the input end of the threshold processing module 24 is connected to the control device 30, the output end of the threshold processing module 24 is connected to the second input end of the detection module 23, and the control device 30 sends a control signal to the threshold processing module 24 so that the threshold processing module 24 outputs the corresponding sampling threshold. The sampling threshold provided by the threshold processing module 24 is transmitted to the second input end of the detection module 23, and the detection module 23 is used to perform signal sampling on the echo signal according to the amplified echo signal and the sampling threshold.

[0041] The detection module 23 can be a TDC (time to digital converter), which samples the echo signal to obtain the reception time of the echo signal and transmits the reception time to the control device 30. The control device 30 calculates the laser flight time based on the reception time, and then obtains information such as the distance of the measured object.

[0042] It is understood that the control device 30 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination of these components. The control device 30 can also be any conventional processor, controller, microcontroller or state machine. The control device 30 can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP and / or any other such configuration, or a combination of one or more of a microcontroller unit (MCU), a field programmable gate array (FPGA), and a system on chip (SoC).

[0043] It can be understood that the control device 30 in the embodiment of the present invention also includes a storage module, which includes but is not limited to: Flash flash memory, NAND flash memory, vertical NAND flash memory (VNAND), NOR flash memory, resistive random access memory (RRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), spin transfer torque random access memory (STT-RAM) and other devices. One or more.

[0044] The specific scenario in which the detection module 23 samples the echo signal is as follows: Figure 4 As shown in the middle left figure, the sampling threshold is A, and the sampling threshold A is compared with the echo signal. When the rising edge of the echo signal crosses the sampling threshold A, the detection module 23 outputs a sampling result. When the falling edge of the echo signal crosses the sampling threshold A, the detection module 23 outputs another sampling result. The characteristics of the echo signal, such as the receiving time, can be obtained by combining the two sampling results.

[0045] The receiving device 20 also includes an AC coupling circuit (not shown in the figure). During signal transmission, the capacitor with a small capacitance value will always be charged and discharged, causing the baseline voltage of the echo signal to sag. If the original sampling threshold A is used, but the baseline voltage sags (such as Figure 4 As shown in the middle right figure), the echo signal that could be sampled using the sampling threshold A may not be sampled or may be sampled inaccurately, thereby affecting the ability of the receiving device 20 to sample weak echo signals and reducing the ranging capability of the laser radar 101.

[0046] In view of the above problems, an embodiment of the present invention provides a receiving control method for a laser radar, which first determines the echo characteristic value of the echo signal of the response period, then determines the baseline voltage fluctuation amount based on the echo characteristic value, and then determines the target sampling threshold according to the baseline voltage fluctuation amount and the sampling threshold of the response period, and finally adjusts the threshold of the next response period according to the target sampling threshold. The receiving control method compensates the sampling threshold to obtain the compensated target sampling threshold, realizes accurate sampling of the echo signal, and improves the ranging effect. At the same time, compared with the fixed threshold compensation, the receiving control method adjusts the sampling threshold in real time based on the influence of the received echo signal on the baseline voltage. The adjusted sampling threshold is consistent with the fluctuation trend of the baseline voltage, so that the target sampling threshold is more matched with the echo signal, further improving the sampling accuracy.

[0047] It can be understood from the above that the laser radar receiving control method provided in the embodiment of the present invention can be implemented by the control device 30 or the processor or by other devices with computing and processing capabilities. It can also be run on a laser radar-based signal processing device based on the von Neumann system. The computer program can be integrated into the application or run as an independent tool application. The laser radar-based signal processing device can be a laser radar-based scanning system, a receiving system, a signal processing system, etc.

[0048] See also Figure 5 , Figure 5 FIG. 1 is a flow chart of a receiving control method of a laser radar provided in an embodiment of the present invention. Figure 5 As shown, the method S100 may specifically include the following steps:

[0049] S11: determining an echo characteristic value of an echo signal of a response period;

[0050] The response cycle is the cycle for the threshold processing module to adjust the sampling threshold. The threshold processing module can adjust the sampling threshold once every response cycle. Limited by the hardware performance of the threshold processing module, the adjustment frequency of the sampling threshold cannot be very high. Usually, a response cycle can include multiple detection cycles, each detection cycle includes at least one echo signal, so a response cycle can include multiple echo signals.

[0051] The echo characteristic value represents the echo energy of the echo signal, and its size represents the strength of the echo energy. The larger the echo characteristic value is, the greater the impact on the baseline voltage is, and the greater the fluctuation of the echo baseline voltage is.

[0052] The echo characteristics of the echo signal can be determined by the duty cycle of the positive pulse in the echo signal and the reference echo amplitude. Figure 6 As shown, step S11 includes:

[0053] S111: Acquire the reference echo amplitudes of all the echo signals in the response period and the duty cycle of the positive pulses of the echo signals; wherein all the echo signals include at least one echo signal;

[0054] The reference echo amplitude characterizes the fluctuation amplitude of the echo signal, and the reference echo amplitude can be determined by a variety of methods. For example, the Vp of the saturated signal is directly calibrated, and it is used as the calibration value, and it is stored in the memory. When determining the reference echo amplitude, the calibration value is directly read and the calibration value is used as the reference echo amplitude. Since the energy of the unsaturated echo signal is relatively small and the difference is not large, it has little effect on the baseline fluctuation. Therefore, the saturated signal is directly calibrated, and the echo amplitude Vp of the saturated signal is used as the reference echo amplitude.

[0055] Another example: based on the set sampling threshold, all the echo signals are sampled to obtain sampling results, and the reference echo amplitude is determined according to the sampling results. Echo signals smaller than the set sampling threshold are not sampled, indicating that they have less energy and less impact on baseline voltage fluctuations, and are no longer used to calculate echo characteristic values. Echo signals higher than the set sampling threshold have greater energy and greater impact on baseline voltage fluctuations, and are used to calculate echo characteristic values.

[0056] The sampling result obtained by sampling is a pair of data, namely (t1, v1) and (t2, v1), t1 is the moment when the rising edge of the echo signal crosses the sampling threshold v1, t2 is the moment when the falling edge of the echo signal crosses the sampling threshold v1, and v1 is the set sampling threshold. Based on the sampling result, the echo amplitude of the echo signal can be calculated, and then the echo amplitude is used as the reference echo amplitude.

[0057] The sampling threshold is set neither too large nor too small, and generally takes the middle value between the zero value and the saturation value of the echo amplitude. Setting the sampling threshold can reuse the sampling threshold of the laser radar system, saving the consumption of laser radar devices. Generally, the sampling threshold in the middle of the multiple sampling thresholds of the laser radar system is reused; it can also be directly set separately as needed. The echo signal is sampled through the detection module in the laser radar system, or through other sampling systems. The sampling results are sent to the control device and stored in the register of the control device. The control device obtains the sampling results corresponding to the set sampling threshold for processing and analysis, and then obtains the reference echo amplitude.

[0058] If the response period contains multiple echo signals, each echo signal will be sampled to obtain its corresponding sampling result, and then the corresponding reference echo amplitude will be obtained based on each sampling result. The reference echo amplitudes corresponding to each echo signal are added together to obtain the reference echo amplitudes of all echo signals in the response period. For example, if the response cycle contains three echo signals, the three echo signals are sampled respectively by setting the sampling threshold, and three sampling results are obtained, namely (t1, v1) and (t2, v1), (t3, v1) and (t4, v1), and (t5, v1) and (t6, v1). Then, the reference echo amplitude Vp1 corresponding to the first echo signal is obtained based on (t1, v1) and (t2, v1), the reference echo amplitude Vp2 corresponding to the second echo signal is obtained based on (t3, v1) and (t4, v1), and the reference echo amplitude Vp3 corresponding to the third echo signal is obtained based on (t5, v1) and (t6, v1). The reference echo amplitude Vp of all echo signals in the response cycle is Vp=Vp1+Vp2+Vp3. The method of obtaining the respective reference echo amplitudes of each echo signal after sampling by the sampling threshold is similar to the above, and will not be repeated.

[0059] For another example, all the echo signals are sampled based on the multiple set sampling thresholds to obtain multiple sampling results, and the reference echo amplitude is determined by weighted averaging the multiple sampling results.

[0060] If the response period includes three echo signals, and three set sampling thresholds are used to sample all echo signals, and the three set sampling thresholds are v1, v2 and v3 respectively, then the sampling results for the first echo signal may be (t1, v1) and (t2, v1), (t3, v2) and (t4, v2), and (t5, v3) and (t6, v3). Then, based on (t1, v1) and (t2, v1), the first reference echo amplitude can be obtained, based on (t3, v2) and (t4, v2), the second reference echo amplitude can be obtained, and based on (t5, v3) and (t6, v3), the third reference echo amplitude can be obtained. The first reference echo amplitude, the second reference echo amplitude and the third reference echo amplitude are weightedly averaged to obtain their corresponding reference echo amplitude Vp1. Since the amplitude of the echo signal sampled by the high threshold is relatively high and the energy of the echo signal is large, when the reference echo amplitude Vp1 is calculated by weighted average, the weighting coefficient of the reference echo amplitude corresponding to the high threshold is high.

[0061] Similarly, a weighted average is performed on the sampling results of the second echo signal to obtain its corresponding reference echo amplitude Vp2, and a weighted average is performed on the sampling results of the third echo signal to obtain its corresponding reference echo amplitude Vp3. Then the reference echo amplitude Vp of all echo signals in the response period is Vp=Vp1+Vp2+Vp3.

[0062] S112: Determine the echo characteristic value of the echo signal based on the reference echo amplitude and the duty cycle.

[0063] The echo characteristic value of the echo signal is determined by the following formula:

[0064] E=Vp*Ton / T;

[0065] Wherein, E is the echo characteristic value, Vp is the reference echo amplitude, Ton is the duration of the positive pulse of all the echo signals in the response period, T is the response period, and Ton / T is the duty cycle.

[0066] The positive pulse of the echo signal indicates the part of the echo signal whose amplitude is greater than the set sampling threshold when the sampling threshold is set to sample the echo signal. If the sampling results of the set sampling threshold v1 are (t1, v1) and (t2, v1), the duration of the positive pulse is (t2-t1). If the response period contains multiple echo signals, the durations of the positive pulses corresponding to the multiple echo signals are accumulated to obtain Ton. If the response period contains 3 echo signals, the 3 echo signals are sampled respectively using the set sampling threshold to obtain 3 sampling results, namely (t1, v1) and (t2, v1), (t3, v1) and (t4, v1), and (t5, v1) and (t6, v1). The duration of the positive pulse is (t2-t1)+(t4-t3)+(t6-t5).

[0067] T is a known constant, Vp and Ton can be measured values, discrete values ​​output in sequence according to the receiving timing, or values ​​calculated in real time based on the sampling results. The control device receives Vp and Ton, and calculates the echo characteristic value of the echo signal based on Vp and Ton.

[0068] S12: determining a baseline voltage fluctuation amount based on the echo characteristic value;

[0069] The larger the echo characteristic value, the greater the impact on the baseline voltage, and thus the greater the baseline voltage fluctuation. Figure 7 As shown, step S12 includes:

[0070] S121: Acquire a preset baseline voltage of the receiving module and an initial baseline voltage of the current response cycle;

[0071] The preset baseline voltage can be set as needed, which is a set value. Usually the preset baseline voltage is the design value of the laser radar system, which is an ideal voltage value without fluctuations. The initial baseline voltage is the baseline voltage corresponding to the start time of the response cycle, and the end baseline voltage is the baseline voltage corresponding to the end time of the response cycle. Therefore, the end baseline voltage of the previous response cycle is the initial baseline voltage of the current response cycle, and the end baseline voltage of the current response cycle is the initial baseline voltage of the next response cycle. Since at least one echo signal is received in each response cycle, the circuit of the receiving device is continuously charged and discharged, so the fluctuation of the baseline voltage is continuously accumulated, and each response cycle is further changed on the basis of the fluctuation of the previous response cycle.

[0072] S122: obtaining an end baseline voltage of the current response cycle based on the echo characteristic value and the initial baseline voltage;

[0073] First, a reference baseline voltage is obtained based on the echo characteristic value and the initial baseline voltage, and then the final baseline voltage is obtained based on the reference baseline voltage and a recovery coefficient, wherein the recovery coefficient is a coefficient of the baseline voltage returning to the preset baseline voltage after being offset.

[0074] The reference baseline voltage is determined by the following formula:

[0075] Vb1=-E+Vb0;

[0076] Wherein, Vb1 is the reference baseline voltage, E is the echo characteristic value, and Vb0 is the initial baseline voltage.

[0077] After the baseline voltage sinks, it will gradually recover to the preset baseline voltage. Due to different hardware performance, different systems require different recovery times. The recovery coefficient is used to characterize the speed of recovery to the preset baseline voltage.

[0078] The recovery coefficient may be a directly set constant K, or a time function F(t), and the time function F(t) may be obtained through simulation or actual measurement fitting.

[0079] After obtaining the reference baseline voltage, the final baseline voltage can be determined by the following formula:

[0080] Vb1' = Vb1*F(t); or,

[0081] Vb1'=Vb1*K;

[0082] Wherein, Vb1' is the end-of-period baseline voltage. Wherein, since the end-of-period baseline voltage of the current response cycle is obtained, the recovery coefficient K at the end of the current response cycle can be obtained by substituting t=T into the time function F(t).

[0083] S123: Determine the baseline voltage fluctuation amount based on the preset baseline voltage and the end-of-period baseline voltage of the current response cycle.

[0084] The difference between the end-of-period baseline voltage and the preset baseline voltage is determined as the baseline voltage fluctuation. From the difference between the end-of-period baseline voltage and the preset baseline voltage, the fluctuation amount of the baseline voltage from the expected preset baseline voltage from the current response cycle to the end of the period can be obtained. Since the baseline voltage fluctuation directly affects the difference between it and the fixed sampling threshold, it further affects the sampling result of the echo signal. The compensation amount of the sampling threshold can be determined by the difference between the end-of-period baseline voltage and the preset baseline voltage, so that the sampling threshold follows the fluctuation trend of the baseline voltage, and the difference between the sampling threshold and the baseline voltage remains stable, so that the echo signal can always be sampled stably.

[0085] S13: determining a target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period;

[0086] Since the baseline voltage and the sampling threshold are both voltage values, the baseline voltage fluctuation amount can directly correspond to the voltage compensation amount required for the sampling threshold, so that the difference between the baseline voltage and the sampling threshold remains stable.

[0087] S14: adjusting the threshold of the next response cycle according to the target sampling threshold.

[0088] The sum of the baseline voltage fluctuation amount and the sampling threshold of the response period is determined as the target sampling threshold.

[0089] The target sampling threshold is the expected threshold to be reached in the next response cycle. In the embodiment of the present invention, the target sampling threshold can be output by the threshold processing module through the PID method. Specifically, the PID parameter is first determined according to the target sampling threshold, and then the control signal of the output threshold of the next response cycle is determined according to the PID parameter. The control signal acts on the threshold processing module, so that the threshold processing module outputs the corresponding target sampling threshold.

[0090] In addition, the lidar system can check whether the threshold output by the threshold processing module is the target sampling threshold in a variety of ways. The threshold output by the threshold processing module can be tested by an instrument. If the target sampling threshold is not reached, the PID parameters are fine-tuned to achieve a match.

[0091] The LiDAR system can also perform a complete machine calibration to see if the adjusted sampling threshold meets expectations.

[0092] An oscilloscope can be used to observe the threshold signal and echo signal output by the threshold processing circuit, observe the change pattern of the echo signal and the threshold signal, and confirm whether the waveform characteristics of the two match. If the echo signal and the threshold signal match, the echo signal becomes higher, and the threshold signal will also become higher following the change pattern of the echo signal. When the echo signal decreases, the threshold signal will also become lower following the change pattern of the echo signal. If the threshold signal and the echo signal match, it indicates that the receiving device can accurately sample the echo signal. This verification method can be used in the design and development stage to facilitate the observation of signal characteristics through an oscilloscope.

[0093] You can also set up a specific scene to calibrate the whole machine. First, set up a target board with adjacent high-reflectivity and low-reflectivity areas on the target board, run the laser radar system for transmission and reception, and observe the first echo signal corresponding to the high-reflectivity area and the second echo signal corresponding to the low-reflectivity area, and whether the pulse width difference between the first echo signal and the second echo signal is less than the preset value. If the sampling threshold can well follow the fluctuation trend of the baseline voltage, the receiving device in the laser radar system can accurately sample the first echo signal and the second echo signal, and the difference between the pulse width corresponding to the first echo signal and the pulse width corresponding to the second echo signal should be less than the preset value, which has taken into account the difference in the pulse width of the echo signals corresponding to high reflection and low reflection. This method can be used in the production stage to facilitate the establishment of specific calibration scenarios.

[0094] If the laser radar system is in operation on the vehicle, the laser can also be used to scan the same object in real time. The baseline voltage fluctuation caused by the same object is usually due to uneven detection cycles, so the characteristics of the baseline voltage fluctuation are similar. The consistency of the echo signal pulse width is detected to evaluate whether the adjustment has reached the expected goal. If the expected goal is achieved and the sampling threshold can follow the trend of the baseline voltage fluctuation, the echo signal pulse width consistency is high.

[0095] Through the above method, different verification methods can be used to verify the receiving control method of the embodiment of the present invention at different stages of the laser radar system to verify whether the sampling threshold adjusted in real time can well follow the trend of the baseline voltage fluctuation, so as to evaluate whether the adjustment of the sampling threshold achieves the expected goal.

[0096] As can be seen from the above, in order to solve the problem that the baseline voltage sinks when the circuit of the receiving device receives the echo signal, and then causes the echo signal sampling to be inaccurate, a fixed threshold compensation can be performed on the sampling threshold based on the fluctuation of the baseline voltage. The compensation amount can be the fluctuation of the baseline voltage, and then the compensated sampling threshold is used to sample the echo signal to improve the sampling accuracy. However, when the laser is emitted to different objects or the laser is emitted at different emission angles, the energy of the reflected echo signal is not equal, or the whole machine is aged or other environmental changes occur, the energy of the reflected echo signal will also change to a certain extent, and the echo energy of the echo signal is strong, the charging and discharging of the AC coupling capacitor is more intensive, and the amplitude of the baseline voltage sinking is higher. The energy fluctuation of the echo signal is unpredictable, and its influence on the baseline voltage is also unpredictable. The fixed threshold compensation cannot change with the echo energy of the echo signal, which makes the sampling accuracy of the echo signal low and the consistency of the detection signal worse. The receiving control method provided in the embodiment of the present invention can adjust the sampling threshold in real time, so that the adjusted sampling threshold is consistent with the fluctuation trend of the baseline voltage, and can better follow the fluctuation trend of the baseline voltage, thereby making the target sampling threshold more matched with the echo signal, further improving the sampling accuracy.

[0097] In summary, the receiving control method of the laser radar first determines the echo characteristic value of the echo signal of the response period, then determines the baseline voltage fluctuation amount based on the echo characteristic value, and then determines the target sampling threshold according to the baseline voltage fluctuation amount and the sampling threshold of the response period, and finally adjusts the threshold of the next response period according to the target sampling threshold. The receiving control method compensates the sampling threshold to obtain the compensated target sampling threshold, realizes accurate sampling of the echo signal, and thus improves the ranging effect. At the same time, compared with the fixed threshold compensation, the receiving control method adjusts the sampling threshold in real time based on the influence of the received echo signal on the baseline voltage, so that the adjusted sampling threshold is consistent with the fluctuation trend of the baseline voltage, so that the target sampling threshold is more matched with the echo signal, and the sampling accuracy is further improved.

[0098] See also Figure 8 , Figure 8 FIG. 1 is a schematic diagram of a receiving control device of a laser radar provided in an embodiment of the present invention. Figure 8 As shown, the receiving control device 200 of the laser radar includes: a first determination module 201, a second determination module 202, a third determination module 203 and an adjustment module 204.

[0099] Among them, the first determination module 201 is used to determine the echo characteristic value of the echo signal of the response period, the second determination module 202 is used to determine the baseline voltage fluctuation amount based on the echo characteristic value, the third determination module 203 is used to determine the target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period, and the adjustment module 204 is used to adjust the threshold value of the next response period according to the target sampling threshold value.

[0100] Optionally, the first determining module 201 is specifically configured to:

[0101] Acquire the reference echo amplitudes of all the echo signals in the response period and the duty cycle of the positive pulses of the echo signals; wherein all the echo signals include at least one echo signal;

[0102] An echo characteristic value of the echo signal is determined based on the reference echo amplitude and the duty cycle.

[0103] Optionally, the first determining module 201 is further specifically configured to:

[0104] Sampling all the echo signals based on a set sampling threshold to obtain a sampling result, and determining the reference echo amplitude according to the sampling result; or,

[0105] Based on the multiple set sampling thresholds, all the echo signals are sampled to obtain multiple sampling results, and the reference echo amplitude is determined according to the weighted average of the multiple sampling results.

[0106] Optionally, the first determining module 201 is further specifically configured to:

[0107] The echo characteristic value of the echo signal is determined by the following formula:

[0108] E=Vp*Ton / T;

[0109] Wherein, E is the echo characteristic value, Vp is the reference echo amplitude, Ton is the duration of the positive pulse of all the echo signals in the response period, T is the response period, and Ton / T is the duty cycle.

[0110] Optionally, the second determining module 202 is specifically configured to:

[0111] Acquire a preset baseline voltage of the receiving module and an initial baseline voltage of the current response cycle;

[0112] Obtaining the final baseline voltage of the current response cycle based on the echo characteristic value and the initial baseline voltage;

[0113] The baseline voltage fluctuation amount is determined based on the preset baseline voltage and the end baseline voltage of the current response cycle.

[0114] Optionally, obtaining an initial baseline voltage of the current response cycle includes:

[0115] The end-of-period baseline voltage of the previous response cycle is obtained, and the end-of-period baseline voltage of the previous response cycle is determined as the initial baseline voltage of the current response cycle.

[0116] Optionally, the second determining module 202 is further specifically configured to:

[0117] Obtaining a reference baseline voltage based on the echo characteristic value and the initial baseline voltage;

[0118] The end-of-period baseline voltage is obtained based on the reference baseline voltage and a recovery coefficient; wherein the recovery coefficient is a coefficient of the baseline voltage returning to the preset baseline voltage after being offset.

[0119] Optionally, obtaining a reference baseline voltage based on the echo characteristic value and the initial baseline voltage includes:

[0120] The reference baseline voltage is determined by the following formula:

[0121] Vb1=-E+Vb0;

[0122] Wherein, Vb1 is the reference baseline voltage, E is the echo characteristic value, and Vb0 is the initial baseline voltage.

[0123] Optionally, determining the baseline voltage fluctuation amount based on the preset baseline voltage and the end-of-period baseline voltage of the current response cycle includes:

[0124] The difference between the end-of-period baseline voltage and the preset baseline voltage is determined as the baseline voltage fluctuation amount.

[0125] Optionally, the third determining module 203 is specifically configured to:

[0126] The sum of the baseline voltage fluctuation amount and the sampling threshold of the response period is determined as the target sampling threshold.

[0127] Optionally, the adjustment module 204 is specifically used for:

[0128] Determine PID parameters according to the target sampling threshold;

[0129] A control signal for outputting a threshold value in the next response period is determined according to the PID parameters.

[0130] In an embodiment of the present invention, the receiving control device of the laser radar can also be constructed by hardware devices. For example, the receiving control device of the laser radar can be constructed by one or more chips, and each chip can work in coordination with each other to complete the receiving control method of the laser radar described in the above embodiments. For another example, the receiving control device of the laser radar can also be constructed by various logic devices, such as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or any combination of these components.

[0131] The laser radar receiving control device provided in the embodiment of the present invention can implement each process that can be implemented by the above-mentioned laser radar receiving control method. To avoid repetition, it will not be described here.

[0132] It should be noted that the above-mentioned laser radar receiving control device can execute the laser radar receiving control method provided in the embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method. For technical details not fully described in the embodiment of the laser radar receiving control device, please refer to the laser radar receiving control method provided in the embodiment of the present invention.

[0133] To sum up, the receiving control device of the laser radar compensates for the sampling threshold to obtain the compensated target sampling threshold, realizes accurate sampling of the echo signal, and thus improves the ranging effect. At the same time, compared with the fixed threshold compensation, the receiving control device of the laser radar adjusts the sampling threshold in real time based on the influence of the received echo signal on the baseline voltage, so that the adjusted sampling threshold is consistent with the fluctuation trend of the baseline voltage, so that the target sampling threshold is more matched with the echo signal, further improving the sampling accuracy.

[0134] The present invention also provides a laser radar. Fig. 9 , Fig. 9 It is a schematic diagram of the hardware structure of a laser radar provided in an embodiment of the present invention.

[0135] like Fig. 9 As shown, the laser radar 300 includes at least one processor 301 and a memory 302 ( Fig. 9 (a bus connection and a processor are used as an example).

[0136] Among them, the processor 301 is used to provide computing and control capabilities to control the laser radar 300 to perform corresponding tasks, for example, to control the laser radar 300 to execute the laser radar receiving control method in any of the above-mentioned method embodiments, the method including determining the echo characteristic value of the echo signal of the response period, determining the baseline voltage fluctuation amount based on the echo characteristic value, determining the target sampling threshold according to the baseline voltage fluctuation amount and the sampling threshold of the response period, and adjusting the threshold of the next response period according to the target sampling threshold.

[0137] In this embodiment, the laser radar compensates the sampling threshold to obtain the compensated target sampling threshold, thereby achieving accurate sampling of the echo signal and improving the ranging effect. At the same time, compared with the fixed threshold compensation, the laser radar adjusts the sampling threshold in real time based on the influence of the received echo signal on the baseline voltage, so that the adjusted sampling threshold is consistent with the fluctuation trend of the baseline voltage, so that the target sampling threshold is more matched with the echo signal, further improving the sampling accuracy.

[0138] The processor 301 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), a hardware chip or any combination thereof; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The above-mentioned PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL) or any combination thereof.

[0139] The memory 302 is a non-transitory computer-readable storage medium that can be used to store non-transitory software programs, non-transitory computer executable programs and modules, such as program instructions / modules corresponding to the laser radar receiving control method in the embodiment of the present invention. The processor 301 can implement the laser radar receiving control method in any of the above-mentioned method embodiments by running the non-transitory software programs, instructions and modules stored in the memory 302. To avoid repetition, it will not be repeated here.

[0140] Specifically, the memory 302 may include a volatile memory (VM), such as a random access memory (RAM); the memory 302 may also include a non-volatile memory (NVM), such as a read-only memory (ROM), a flash memory, a hard disk drive (HDD) or a solid-state drive (SSD) or other non-transitory solid-state storage device; the memory 302 may also include a combination of the above types of memory.

[0141] In an embodiment of the present invention, the memory 302 may also include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0142] In an embodiment of the present invention, the laser radar 300 may also include other components for realizing the functions of the device, which will not be described in detail here.

[0143] The embodiment of the present invention further provides a computer-readable storage medium, such as a memory including a program code, and the program code can be executed by a processor to complete the receiving control method of the laser radar in the above embodiment. For example, the computer-readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CDROM), a magnetic tape, a floppy disk, and an optical data storage device.

[0144] An embodiment of the present invention further provides a computer program product, which includes one or more program codes, and the program codes are stored in a computer-readable storage medium. A processor of an electronic device reads the program code from the computer-readable storage medium, and the processor executes the program code to complete the method steps of the laser radar receiving control method provided in the above embodiment.

[0145] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0146] Through the description of the above implementation methods, ordinary technicians in this field can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Ordinary technicians in this field can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser radar receiving control method, characterized in that: The method comprises: Determine the echo characteristic value of the echo signal of the response period; Determine a baseline voltage fluctuation amount based on the echo characteristic value; Determine a target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period; The threshold of the next response cycle is adjusted according to the target sampling threshold.

2. The method according to claim 1, characterized in that The step of determining the echo characteristic value of the echo signal of the response period includes: Acquire the reference echo amplitudes of all the echo signals in the response period and the duty cycle of the positive pulses of the echo signals; wherein all the echo signals include at least one echo signal; An echo characteristic value of the echo signal is determined based on the reference echo amplitude and the duty cycle.

3. The method according to claim 2, characterized in that The obtaining of reference echo amplitudes of all the echo signals in the response period includes: Sampling all the echo signals based on a set sampling threshold to obtain a sampling result, and determining the reference echo amplitude according to the sampling result; or, Based on the multiple set sampling thresholds, all the echo signals are sampled to obtain multiple sampling results, and the reference echo amplitude is determined according to the weighted average of the multiple sampling results.

4. The method according to claim 2, characterized in that: The determining the echo characteristic value of the echo signal based on the reference echo amplitude and the duty cycle includes: The echo characteristic value of the echo signal is determined by the following formula: E=Vp*Ton / T; Wherein, E is the echo characteristic value, Vp is the reference echo amplitude, Ton is the duration of the positive pulse of all the echo signals in the response period, T is the response period, and Ton / T is the duty cycle.

5. The method according to claim 1, characterized in that The determining of the baseline voltage fluctuation amount based on the echo characteristic value comprises: Acquire a preset baseline voltage of the receiving module and an initial baseline voltage of the current response cycle; Obtaining the final baseline voltage of the current response cycle based on the echo characteristic value and the initial baseline voltage; The baseline voltage fluctuation amount is determined based on the preset baseline voltage and the end baseline voltage of the current response cycle.

6. The method according to claim 5, characterized in that Obtaining the initial baseline voltage of the current response cycle, including: The end-of-period baseline voltage of the previous response cycle is obtained, and the end-of-period baseline voltage of the previous response cycle is determined as the initial baseline voltage of the current response cycle.

7. The method according to claim 5, characterized in that The step of obtaining the final baseline voltage of the current response cycle based on the echo characteristic value and the initial baseline voltage comprises: Obtaining a reference baseline voltage based on the echo characteristic value and the initial baseline voltage; The end-of-period baseline voltage is obtained based on the reference baseline voltage and a recovery coefficient; wherein the recovery coefficient is a coefficient of the baseline voltage returning to the preset baseline voltage after being offset.

8. The method according to claim 7, characterized in that The obtaining a reference baseline voltage based on the echo characteristic value and the initial baseline voltage comprises: The reference baseline voltage is determined by the following formula: Vb1=-E+Vb0; Wherein, Vb1 is the reference baseline voltage, E is the echo characteristic value, and Vb0 is the initial baseline voltage.

9. The method according to claim 5, characterized in that The determining the baseline voltage fluctuation amount based on the preset baseline voltage and the end baseline voltage of the current response cycle includes: The difference between the end-of-period baseline voltage and the preset baseline voltage is determined as the baseline voltage fluctuation amount.

10. The method according to any one of claims 1 to 9, characterized in that: The step of determining a target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period includes: The sum of the baseline voltage fluctuation amount and the sampling threshold of the response period is determined as the target sampling threshold.

11. The method according to claim 1, characterized in that: The step of adjusting the threshold of the next response cycle according to the target sampling threshold comprises: Determine PID parameters according to the target sampling threshold; A control signal for outputting a threshold value in the next response period is determined according to the PID parameters.

12. A receiving control device for a laser radar, characterized in that: The receiving control device comprises: A first determination module, used to determine an echo characteristic value of an echo signal of a response period; A second determination module, configured to determine a baseline voltage fluctuation amount based on the echo characteristic value; A third determination module, configured to determine a target sampling threshold value according to the baseline voltage fluctuation amount and the sampling threshold value of the response period; An adjustment module is used to adjust the threshold of the next response cycle according to the target sampling threshold.

13. A laser radar, characterized in that: include: at least one processor; A memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the receiving control method of the laser radar as described in any one of claims 1-11.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer device to execute the laser radar receiving control method as described in any one of claims 1-11.

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