WO2018176288A1

WO2018176288A1 - Laser radar and time measurement method based on laser radar

Info

Publication number: WO2018176288A1
Application number: PCT/CN2017/078661
Authority: WO
Inventors: 刘祥; 占志鹏; 蒲文进; 洪小平
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2017-03-29
Filing date: 2017-03-29
Publication date: 2018-10-04
Also published as: CN108401444A; CN108401444B

Abstract

Provided is a laser radar. The laser radar comprises a photosensor (110), an amplification circuit (120), a comparison circuit (130), and a controller (140). The photosensor is used for receiving an optical pulse signal, converting the optical pulse signal into an electrical signal and outputting the electrical signal to the amplification circuit. The amplification circuit is used for performing amplification operation on the electrical signal inputted from the photosensor and outputting the electric signal on which the amplification operation has been performed to the comparison circuit. The comparison circuit is used for performing comparison operation on the electrical signal inputted from the amplification circuit with a preset threshold, and extracting time information corresponding to the electrical signal. The controller is used for adjusting the gain of the photosensor or adjusting a preset threshold of the comparison circuit, so that a noise signal is lower than the preset threshold. Also provided is a time measurement method based on the laser radar. The distortion of measured time information caused by triggering of the comparison circuit by a noise signal when the strength of the noise signal is greater than a preset threshold can be avoided, thereby improving the accuracy of time measurement.

Description

Lidar and time measurement method based on laser radar

Technical field

The invention relates to the technical field of laser radar, in particular to a laser radar and a time measurement method based on laser radar.

Background technique

A laser radar is a radar system that emits a laser beam to detect the position and velocity of a target. The photosensitive sensor of the laser radar can convert the acquired optical pulse signal into an electrical signal, and obtain time information corresponding to the electrical signal based on the comparator, thereby obtaining distance information between the laser radar and the target.

However, the environmental conditions of the operation of the laser radar are complicated, and the intensity of the obtained electrical signal has a large dynamic range, and the noise signal included in the electrical signal is also strong or weak. Based on the way the comparator collects time information, the voltage threshold is fixed, and the noise signal included in the wide dynamic electrical signal may trigger the comparator, causing distortion of the measured time information.

Summary of the invention

In a first aspect, an embodiment of the present invention provides a laser radar, including: a photosensitive sensor, an amplifying circuit, a comparing circuit, and a controller; wherein

The photosensitive sensor is configured to receive an optical pulse signal, and convert the optical pulse signal into an electrical signal, and output the electrical signal to the amplifying circuit;

The amplifying circuit is configured to amplify an electrical signal input from the photosensitive sensor, and output the amplified electrical signal to the comparison circuit;

The comparison circuit is configured to compare an electrical signal input from the amplifying circuit with a preset threshold, and extract time information corresponding to the electrical signal;

The controller is configured to adjust a gain of the photosensor or adjust a preset threshold of the comparison circuit such that the noise signal is lower than the preset threshold.

Compared with the prior art, the present invention provides a laser radar to adjust the gain of the photosensitive sensor or adjust the preset threshold of the comparison circuit to avoid the measurement caused by the noise signal triggering comparison circuit when the intensity of the noise signal exceeds a preset threshold. Distortion of time information improves the accuracy of time measurement.

Optionally, the comparison circuit includes at least one comparator, a first input of the comparator is configured to receive an electrical signal input from the amplifying circuit, and a second input of the comparator is configured to receive the And a preset threshold, the output of the comparator is configured to output a result of the comparison operation, wherein the result of the comparison operation includes time information corresponding to the electrical signal.

Optionally, the comparison circuit further includes a time-to-digital converter electrically connected to the output end of the comparator for extracting and Time information corresponding to the electrical signal.

Optionally, the preset threshold is determined according to the strength of the noise signal, such that the preset threshold is higher than the noise signal and the difference between the preset threshold and the maximum value of the noise signal is not greater than a preset value.

Optionally, the laser radar further includes a digital-to-analog converter, the controller is connected to the second input end of the comparator through the digital-to-analog converter, and by controlling an output voltage of the digital-to-analog converter The size is adjusted to adjust the preset threshold of the comparison circuit.

Optionally, the laser radar further includes a comparison threshold adjustment circuit, the comparison threshold adjustment circuit includes a plurality of resistors, one end of the plurality of resistors being commonly connected to the second input end of the comparator, and the plurality of voltage signals The other end of the plurality of resistors is configured to provide the preset threshold to the second input end of the comparator through the plurality of resistors, and adjust the input to the constituent structure of the plurality of resistors The predetermined threshold of the second input of the comparison circuit.

Optionally, the laser radar further includes a power management circuit electrically connected to the controller and the photosensitive sensor, wherein the power management circuit is configured to provide a working voltage for the photosensitive sensor, The controller adjusts the gain of the photosensor by controlling the power management circuit to change the operating voltage.

Optionally, the photosensor includes an avalanche photodiode, and a cathode of the avalanche photodiode is electrically connected to the power management circuit for acquiring an operating voltage from the power management circuit, an anode of the avalanche photodiode An input terminal of the amplifying circuit is connected, the avalanche photodiode is configured to receive an optical pulse signal, and convert the optical pulse signal into an electrical signal, and output the electrical signal to the amplifying circuit.

Optionally, the noise signal includes an optical noise signal and an electronic noise signal, and the controller is further configured to acquire and compare an intensity of the optical noise signal and an intensity of the electronic noise signal, and the optical noise signal Adjusting the preset threshold of the comparison circuit when the intensity is less than the intensity of the electronic noise signal a value such that the noise signal is below the predetermined threshold.

Optionally, the controller is further configured to acquire an intensity of the noise signal, and when a strength of the noise signal is less than a preset noise threshold, adjust a preset threshold of the comparison circuit, so that the noise signal is low. At the preset threshold.

Optionally, the noise signal includes an optical noise signal and an electronic noise signal, and the controller is further configured to acquire and compare an intensity of the optical noise signal and an intensity of the electronic noise signal, and the optical noise signal When the intensity is greater than the intensity of the electronic noise signal, the gain of the photosensor is adjusted such that the noise signal is below the predetermined threshold.

Optionally, the controller is further configured to acquire an intensity of the noise signal, and adjust a gain of the photosensor when the intensity of the noise signal is greater than a preset noise threshold, so that the noise signal is lower than Preset thresholds.

Optionally, the controller is further configured to determine whether the noise signal is higher than the preset threshold.

Optionally, the controller is further configured to:

Obtaining a random noise number in the initial image generated by the laser radar, and determining whether the random noise number is higher than a preset noise number threshold; the initial image is an electrical signal input by the controller according to the slave amplification circuit And generating an initial image by using a preset threshold before adjustment;

And if the random noise number is higher than a preset noise number threshold, determining that the noise signal is higher than the preset threshold.

Optionally, the laser radar further includes a root mean square detector, wherein the controller is electrically connected to the amplifying circuit through the root mean square detector for detecting that the noise signal is within a preset frequency range. Power information, and outputting the power information to the controller, the controller is further configured to:

Determining whether the power information input by the rms detector exceeds a preset power threshold;

And if the power information exceeds the preset power threshold, determining that the noise signal is higher than the preset threshold.

Optionally, the comparison circuit includes a plurality of comparators and a plurality of TDCs, the TDCs are connected in one-to-one correspondence with the comparators, and the first input ends of the plurality of comparators are configured to receive the slave amplifier circuits Inputting an electrical signal, the second input ends of the plurality of comparators are electrically connected to the controller, respectively for receiving a threshold; the outputs of the plurality of comparators are respectively corresponding to the comparator and the comparator The connected TDC is electrically connected to the controller, and the comparator outputs a comparison result to the TDC, the plurality of The TDC measures time information according to the comparison result and outputs the time information to the controller; the controller is further configured to:

Calculating and comparing second time information corresponding to the first time information of the comparator of the first threshold of the plurality of comparators and the comparator of the second threshold; wherein the first threshold is smaller than the second threshold;

If the difference between the first time information and the second time information is a random value, and the difference between the first time information and the second time information is greater than a preset time threshold, determining that the noise signal is higher than The first threshold.

Optionally, the controller is further configured to: select a threshold that is lower than a threshold of the noise signal as the preset threshold.

Optionally, the controller is further configured to: fit a waveform of an electrical signal input to the comparator according to time information measured by the plurality of time-to-digital converters, and calculate a time corresponding to the electrical signal according to the fitted waveform information.

Compared with the prior art, the laser radar provided by the embodiment of the present invention receives the received optical pulse signal through the photosensitive sensor, and converts the optical pulse signal into an electrical signal, and performs an amplification operation on the electrical signal through the amplifying circuit to adjust the gain of the photosensitive sensor. Or adjusting the preset threshold of the comparison operation so that the noise signal is lower than the preset threshold; the noise signal is a noise signal included in the amplified electrical signal, and the comparison operation circuit performs the amplified electrical signal with a preset threshold The comparison operation extracts time information corresponding to the electrical signal, thereby preventing the noise signal from triggering the distortion of the measured time information caused by the comparison circuit when the intensity of the noise signal exceeds a preset threshold.

Moreover, the laser radar can dynamically adjust the gain of the photosensitive sensor or the preset threshold of the comparison circuit according to the intensity of the noise signal, and then reduce the preset threshold as much as possible when the preset threshold is greater than the noise signal, and the accuracy of the time measurement is high.

In a second aspect, an embodiment of the present invention further provides a time measurement method based on a laser radar, including:

Receiving a received optical pulse signal through a photosensor, and converting the optical pulse signal into an electrical signal;

Amplifying the electrical signal;

Adjusting a gain of the photosensor, or adjusting a preset threshold of the comparison operation, so that the noise signal is lower than the preset threshold; the noise signal is a noise signal included in the amplified electrical signal;

And comparing the amplified electrical signal with the preset threshold, and extracting time information corresponding to the electrical signal.

Optionally, the adjusting the preset threshold of the comparison operation includes: determining a preset threshold according to an intensity of the noise signal, such that the preset threshold is higher than the noise signal, and the preset threshold and the maximum of the noise signal are The difference between the values is not greater than the preset value.

Optionally, the noise signal includes an optical noise signal and an electronic noise signal; and adjusting the gain of the photosensor or adjusting a preset threshold of the comparison operation, so that the noise signal is lower than the preset threshold, includes:

Acquiring and comparing the intensity of the optical noise signal and the strength of the electronic noise signal;

When the intensity of the optical noise signal is less than the intensity of the electronic noise signal, adjusting a preset threshold of the comparison operation such that the noise signal is lower than the preset threshold;

When the intensity of the optical noise signal is greater than the intensity of the electronic noise signal, the gain of the photosensor is adjusted such that the noise signal is lower than the preset threshold.

Optionally, the adjusting the gain of the photosensor or adjusting the preset threshold of the comparison operation such that the noise signal is lower than the preset threshold includes:

Obtaining the intensity of the noise signal in the electrical signal after the amplification operation;

And adjusting, when the intensity of the noise signal is less than a preset noise threshold, a preset threshold of the comparison operation, so that the noise signal is lower than the preset threshold;

When the intensity of the noise signal is greater than a preset noise threshold, the gain of the photosensor is adjusted such that the noise signal is lower than the preset threshold.

Optionally, after the amplifying the electrical signal, the adjusting the gain of the photosensor or adjusting a preset threshold of the comparison operation; the method further includes:

Determining whether the noise signal is higher than the preset threshold;

When the noise signal is higher than the preset threshold, the step of adjusting the gain of the photosensor or adjusting the preset threshold of the comparison operation is performed.

Optionally, the determining whether the noise signal is higher than the preset threshold includes:

Obtaining a random noise number in the initial image generated by the laser radar, and determining the random noise Whether the number is higher than a preset noise number threshold; the initial image is generated by the laser radar according to the electrical signal after the amplification operation and a preset threshold before adjustment;

Detecting power information of the noise signal within a preset frequency range;

Optionally, the laser radar includes a plurality of comparators and a plurality of time-to-digital converters, the comparators are connected in one-to-one correspondence with the time-to-digital converter, and determining whether the noise signal is higher than the preset threshold include:

Comparing the amplified electrical signal with a threshold of the plurality of comparators, and measuring time information corresponding to the plurality of comparators by the plurality of time-to-digital converters;

Calculating and comparing the second time information corresponding to the first time information of the comparator corresponding to the preset threshold and the comparator of the first threshold; wherein the preset threshold is smaller than the first threshold;

If the difference between the first time information and the second time information is a random value, and the difference between the first time information and the second time information is greater than a preset time threshold, determining that the noise signal is higher than The preset threshold.

Optionally, after determining whether the noise signal is higher than the preset threshold, before the adjusting the preset threshold of the comparison operation, the method further includes: selecting a threshold that is lower than a threshold of the noise signal. As the preset threshold.

Optionally, the comparing, comparing the amplified electrical signal with the preset threshold, and extracting time information corresponding to the electrical signal includes:

Comparing the amplified electrical signal with a threshold of the plurality of comparators, and measuring time information corresponding to the plurality of comparators by the plurality of time digital converters;

And fitting, according to time information measured by the plurality of time-to-digital converters, a waveform of the electrical signal after the amplification operation, and calculating time information corresponding to the electrical signal according to the fitted waveform.

In the embodiment of the invention, the laser radar receives the received light pulse signal through the photosensitive sensor, converts the optical pulse signal into an electrical signal, performs an amplification operation on the electrical signal, and dynamically adjusts the gain of the photosensitive sensor. Or dynamically adjusting the preset threshold of the comparison operation so that the noise signal is lower than the preset threshold, the noise signal is a noise signal included in the amplified electrical signal; and comparing the amplified electrical signal with a preset threshold And extracting time information corresponding to the electrical signal, thereby preventing the noise signal from triggering the distortion of the measured time information caused by the comparison circuit when the intensity of the noise signal exceeds a preset threshold.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

1 is a schematic frame diagram of a laser radar according to an embodiment of the present invention;

2 is a schematic frame diagram of another laser radar according to an embodiment of the present invention;

3 is a schematic diagram of a first method for avoiding a noise signal triggering comparison circuit according to an embodiment of the present invention;

4 is a schematic diagram of a second method for avoiding a noise signal triggering comparison circuit according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a principle of a time extraction method according to an embodiment of the present invention; FIG.

FIG. 6 is a schematic circuit diagram of a first implementation manner of adjusting a preset threshold according to an embodiment of the present disclosure;

FIG. 7 is a schematic circuit diagram of a second implementation manner of adjusting a preset threshold according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of still another laser radar according to an embodiment of the present invention; FIG.

9 is a circuit diagram of an ACF gain adjustment circuit for an avalanche photodiode according to an embodiment of the present invention;

FIG. 10 is a schematic flow chart of a time measurement method based on laser radar according to an embodiment of the present invention.

detailed description

The embodiments of the present invention will be described in detail with reference to the accompanying drawings in the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Please refer to FIG. 1. FIG. 1 is a schematic frame diagram of a laser radar according to an embodiment of the present invention. The laser radar may include a photosensor 110, an amplifying circuit 120, a comparison circuit 130, a controller 140, and the like. One end of the photosensor 110 is electrically connected to the first end of the amplifying circuit 120, and the other end of the photosensor is electrically connected to the controller 140; the second end of the amplifying circuit 120 is electrically connected to the comparing circuit 130 and the controller 140, respectively; It is electrically connected to the comparison circuit 130. among them,

The photosensitive sensor 110 is configured to: acquire an optical pulse signal, and convert the optical pulse signal into a first electrical signal; output the electrical signal to the amplifying circuit 120;

The amplifying circuit 120 is configured to amplify the electrical signal input from the photosensor 110, and output the amplified electrical signal to the comparing circuit 130;

The comparison circuit 130 is configured to compare the electrical signal input from the amplifying circuit 120 with a preset threshold, and extract time information corresponding to the electrical signal;

The controller 140 is configured to adjust the gain of the photosensor 110 or adjust the preset threshold of the comparison circuit 130 such that the noise signal is lower than a preset threshold.

The noise signal is noise carried in the electrical signal after the amplification operation.

It can be understood that the laser radar adjusts the gain of the photosensor 110 or adjusts the preset threshold of the comparison circuit 130 to prevent the noise signal from triggering the distortion of the measured time information caused by the comparison circuit when the noise signal is greater than the preset threshold.

In an embodiment of the present invention, the comparison circuit 130 includes at least one comparator. Referring to FIG. 2, FIG. 2 is a schematic frame diagram of another laser radar according to an embodiment of the present invention. As shown in FIG. 2, the first input end of the comparator 1301 is configured to receive an electrical signal input from the amplifying circuit 120, that is, to amplify the calculated electrical signal, and the second input end of the comparator 1301 is configured to receive a preset threshold. The output of the comparator 1301 is configured to output a result of the comparison operation, wherein the result of the comparison operation includes a corresponding to the electrical signal Time information. It can be understood that the preset threshold received by the second input of the comparator 1301 may be an electrical signal whose intensity is a preset threshold. The result of the comparison operation may be a digital signal corresponding to the electrical signal after the amplification operation.

Optionally, the comparison circuit 130 further includes a Time-to-Digital Converter (TDC) 1302. The time-to-digital converter 1302 is electrically connected to the output of the comparator 1301 for comparing operations according to the output of the comparator 1301. As a result, time information corresponding to the electrical signal is extracted.

Optionally, the controller 140 is further configured to acquire time information, calculate distance information corresponding to the time information, and generate an image or the like according to the distance information, which is not limited by the present invention.

It can be understood that the electrical signal includes noise, and the amplified electrical signal also includes a noise signal.

The noise signal can be prevented from triggering the comparison circuit 130 in two ways. Method 1: By adjusting the preset threshold of the comparison circuit, that is, the preset threshold of the comparator. Please refer to FIG. 3. FIG. 3 is a schematic diagram of the first method for avoiding a noise signal triggering comparison circuit according to an embodiment of the present invention. The electrical signal 310 input to the first input end of the comparator includes an electrical pulse signal U1 and a noise signal U2. When the preset threshold is the threshold value V1, the intensity of the noise signal exceeds the threshold value V1, and the noise signal triggers the comparator to output a high level signal, resulting in The distortion of the output signal of the comparator further causes an error of the extracted time information; the preset threshold may be increased, for example, the preset threshold is adjusted to the threshold V2, and the intensity of the noise signal is less than the threshold V1, thereby preventing the noise signal U2 from triggering the comparator .

Method 2: Adjust the intensity of the electrical signal by adjusting the gain of the photosensitive sensor (such as APD), so that the electrical signal input from the amplifying circuit, that is, the intensity of the noise signal in the amplified electrical signal is lower than a preset threshold. Please refer to FIG. 4. FIG. 4 is a schematic diagram showing the principle of a second noise avoidance signal trigger comparison circuit according to an embodiment of the present invention. The electrical signal 410 shown by the solid line is an electrical signal input to the first input of the comparator before adjusting the gain of the photosensor. The electrical signal 410 includes the electrical pulse signal U1 and the noise signal U2. When the preset threshold is the threshold V1, the noise The strength of the signal exceeds the threshold V1, and the noise signal triggers the comparator to output a high level signal, resulting in distortion of the comparator output signal. At this time, the gain of the photosensor can be reduced. After the gain of the photosensor is lowered, the electric signal input to the first input end of the comparator (ie, the electric signal 420 indicated by the broken line) is adjusted in proportion to the electric signal 410 after adjusting the gain of the photosensor. The intensity of the electrical pulse signal U1' and the noise signal U2' in the electrical signal 420 is lowered, so that the noise signal U2' is smaller than the preset threshold V1, thereby preventing the noise signal U2' from triggering the comparator.

In an embodiment of the present invention, in the first method for preventing the noise signal from being triggered to the preset threshold, the controller 140 is further configured to: adjust the preset threshold according to the intensity of the noise signal, so that the preset threshold is smaller than the strength of the noise signal, Under the wide dynamic optical pulse signal, the preset threshold of the comparison circuit is dynamically adjusted according to the intensity of the noise signal in the electrical signal after the amplification operation.

Referring to FIG. 5, FIG. 5 is a schematic diagram of a principle of a time extraction method according to an embodiment of the present invention. As shown in FIG. 5, the electrical signal 510 of the input comparison circuit is compared with a preset threshold V1 to obtain a first square wave signal 520 as indicated by a broken line. The time T1 of the edge of the first square wave signal 520 may be It is considered the time when the electrical signal 510 traverses the comparator. Similarly, the electrical signal 510 of the input comparison circuit is compared with the preset threshold V2 to obtain a second square wave signal 530 as indicated by a broken line, and the time T2 of the transition edge of the second square wave signal 530 can be regarded as an electrical signal. The time when the 510 traverses the comparator, and T0 is the real time when the electrical signal 510 traverses the comparator. It can be seen that the smaller the preset threshold is, the closer the hopping time is to the real time when the electrical signal after the amplification operation crosses the comparator.

Optionally, the controller 140 is further configured to: determine a preset threshold according to the strength of the noise signal, such that the preset threshold is higher than the noise signal, and the difference between the preset threshold and the maximum value of the noise signal is not greater than a preset value, such as 0.1V. , 0.2A, etc., realize that the laser radar determines the most appropriate preset threshold value of the comparison circuit 130 according to the intensity of the noise signal, and minimizes the preset threshold value on the premise that the preset threshold value is greater than the noise signal, so that the time information extracted by the comparison circuit 130 is obtained. It is closer to the real time when the electrical signal input from the amplifying circuit traverses the comparison circuit 130, and avoids the error caused by the variation of the signal amplitude on the acquisition of the time information, and the accuracy of the time measurement is high.

In an embodiment of the present invention, a first implementation manner of adjusting a preset threshold may be referred to FIG. 6. FIG. 6 is a schematic circuit diagram of a first implementation manner of adjusting a preset threshold according to an embodiment of the present invention. The laser radar may further include a digital to analog converter 150. As shown in FIG. 6, the controller 140 may be connected to the second input terminal of the comparison circuit 130 through the digital to analog converter 150, and by controlling the output voltage of the digital to analog converter 150. Size to adjust the preset threshold of the comparison circuit.

In an embodiment of the present invention, the second implementation manner of adjusting the preset threshold may be: the laser radar may further include a comparison threshold adjustment circuit, and the comparison threshold adjustment circuit includes a plurality of resistors, and one end of the plurality of resistors is connected to the comparator The two input ends, the plurality of voltage signals are input to the other end of the plurality of resistors, and are used for providing a preset threshold to the second input end of the comparator through the plurality of resistors, and adjusting the input structure to the comparison circuit by adjusting the composition of the plurality of resistors The preset threshold of the second input.

For example, please refer to FIG. 7. FIG. 7 is a schematic circuit diagram of a second implementation manner of adjusting a preset threshold according to an embodiment of the present invention. The comparison threshold adjustment circuit 160 includes a plurality of resistors, such as a first resistor R1, a second resistor R2, a third resistor R3, and the like. The first end of the first resistor R1, the second resistor R2, and the third resistor R3 are commonly connected to the second input end of the comparator 1301, and the other ends of the first resistor R1, the second resistor R2, and the third resistor R3 are respectively The plurality of identical input/output interfaces 1601 of the controller 140 are connected one by one, and the controller 140 adjusts the preset threshold of the comparison circuit 130 by controlling the level of the output levels of the plurality of same input/output interfaces 1601.

In an embodiment of the present invention, in a method for triggering a noise avoidance signal to a preset threshold, please refer to FIG. 8. FIG. 8 is a schematic structural diagram of another laser radar according to an embodiment of the present invention. The laser radar may further include a power management circuit 170 electrically connected to the controller 140 and the photosensor 110, the power management circuit 170 for supplying the operating voltage to the photosensor 110, and the controller 140 changing the operation by controlling the power management circuit 170. The voltage is used to adjust the gain of the photosensor 110.

For example, please refer to FIG. 9. FIG. 9 is a schematic circuit diagram of an ACF gain adjustment circuit for an avalanche photodiode according to an embodiment of the present invention. The photosensor 110 includes an avalanche photodiode 1101. The cathode of the avalanche photodiode 1101 is electrically connected to the power management circuit 170 for obtaining an operating voltage from the power management circuit 170. The anode of the avalanche photodiode 1101 is connected to the input end of the amplifying circuit, and the avalanche photoelectric The diode 1101 is for receiving an optical pulse signal, and converting the optical pulse signal into an electrical signal, and outputs the electrical signal to the amplifying circuit 120.

It can be understood that the larger the operating voltage is, the larger the gain of the APD is, and the larger the optical pulse signal and the noise signal acquired by the APD.

Alternatively, the controller 140 may also determine the operating voltage of the photosensor 110 based on the intensity of the noise signal. It can be understood that the large noise signal corresponds to a smaller operating voltage, and conversely, the first noise signal corresponds to a higher operating voltage.

It should be noted that the laser radar may choose to adopt method one or method two to prevent the noise signal from being triggered to a preset threshold. It can be understood that the noise signal can include an electronic noise signal as well as an optical noise signal.

In the embodiment of the present invention, the controller 140 is further configured to acquire and compare the intensity of the optical noise signal and the intensity of the electronic noise signal, and when the intensity of the optical noise signal is less than the intensity of the electronic noise signal, that is, when the electronic noise is dominant, In the first method, the preset threshold of the comparison circuit 130 is adjusted so that the noise signal is lower than the preset threshold; when the intensity of the optical noise signal is greater than the intensity of the electronic noise signal, that is, the light When the noise is dominant, the gain of the photosensor 110 is adjusted by the above method 2, so that the noise signal is lower than the preset threshold.

It can be understood that for a given electronic device, the intensity of the electronic noise is relatively stable, and the intensity of the optical noise is greatly affected by the environment. The higher the light intensity in the environment, the higher the intensity of the optical noise. Therefore, the intensity of the noise signal can be measured to characterize the intensity of the optical noise.

In the embodiment of the present invention, the controller 140 is further configured to acquire the strength of the noise signal. When the strength of the noise signal is less than the preset noise threshold, the method 1 adjusts the preset threshold of the comparison circuit 130 to make the noise signal low. The preset threshold is used. When the intensity of the noise signal is greater than the preset noise threshold, the gain of the photosensor 110 is adjusted by the method 2 above, so that the noise signal is lower than the preset threshold.

In the embodiment of the present invention, when the noise signal triggering comparison circuit 130 is detected, the controller 140 may also trigger the adjustment by the preset threshold of the pair of methods or adjust the gain of the photosensitive sensor 110 by the second method.

The controller 140 may be further configured to determine whether the noise signal is higher than a preset threshold. When the noise signal is higher than the preset threshold, the trigger controller adjusts the gain of the photosensor 110 or adjusts the preset threshold of the comparison circuit 130; The controller 140 does not perform the adjustment of the gain of the photosensor 110 or the preset threshold of the comparison circuit 130.

The first embodiment of the controller 140 determining whether the noise signal is higher than the preset threshold may be: the controller 140 acquires the random noise number in the initial image generated by the laser radar, and determines whether the random noise number is higher than the preset noise threshold. The initial image is that the controller 140 generates an initial image according to the electrical signal input from the amplifying circuit and the preset threshold before the adjustment. If the random noise number is higher than the preset noise threshold, the noise signal is determined to be higher than the preset threshold; otherwise, the determination is performed. The noise signal is below a preset threshold.

The second embodiment in which the controller 140 determines whether the noise signal is higher than a preset threshold may be that the laser radar further includes a root mean square detector, and the controller 140 is electrically connected to the amplifying circuit 120 through the root mean square detector for detecting The power information of the noise signal is in a preset frequency range, and the power information is output to the controller 140. The controller 140 is further configured to: determine whether the power information input by the rms detector exceeds a preset power threshold, and if the power information exceeds The power threshold is preset to determine that the noise signal is higher than a preset threshold; otherwise, the noise signal is determined to be lower than a preset threshold.

The third implementation manner of the controller 140 determining whether the noise signal is higher than the preset threshold may be: the comparison circuit 130 includes a plurality of comparators and a plurality of TDCs, wherein the TDC is connected to the comparators one by one, The first input ends of the plurality of comparators are configured to receive the electrical signals input from the amplifying circuit 120, and the second input terminals 140 of the plurality of comparators are electrically connected to receive the thresholds respectively; the outputs of the plurality of comparators are respectively The TDC is electrically connected to the controller, and the comparator outputs a comparison result to the TDC. The TDC measures the time information according to the comparison result and outputs the time information to the controller. The controller 140 is further configured to: calculate and compare the preset thresholds of the plurality of comparators 1301. The first time information corresponding to the comparator 130 corresponds to the second time information corresponding to the comparator of the first threshold, wherein the preset threshold is smaller than the first threshold, and if the difference between the first time information and the second time information is a random value, If the difference between the first time information and the second time information is greater than the preset time threshold, the noise signal is determined to be higher than the preset threshold; otherwise, the noise signal is determined to be lower than the preset threshold.

Optionally, when the laser radar includes multiple comparators and multiple TDCs, the controller 140 is further configured to: select a threshold value that is the lowest of the thresholds higher than the noise signal as a preset threshold, and further, acquire a higher than noise signal. The minimum threshold of the threshold and the electrical signal input from the amplifying circuit pass through the time information output by the comparing circuit, and further reduce the preset threshold as the preset threshold is greater than the noise signal, so that the time information extracted by the comparing circuit 130 is closer to The real time when the electrical signal input by the amplifying circuit 120 traverses the comparison circuit 130 reduces the error caused by the change of the signal amplitude to the acquisition of the time information, and the accuracy of the time measurement is high.

Optionally, when the laser radar includes multiple comparators and multiple TDCs, the thresholds of the multiple comparators may be the same, and the controller 140 is further configured to: calculate time information corresponding to the electrical signals according to the time information measured by the multiple TDCs. For example, taking the average value of the time information measured by the TDC as the time information corresponding to the electrical signal, and then calibrating the time information corresponding to the electrical signal, so that the time precision of the measurement is higher.

Optionally, when the laser radar includes multiple comparators and multiple TDCs, the thresholds of the multiple comparators may be different, and the controller is further configured to: fit the electrical signals of the input comparator according to the time information measured by the multiple TDCs. The waveform of the electric wave is calculated according to the waveform of the fitting. Referring to FIG. 5, T0 can be regarded as the time information corresponding to the electrical signal, thereby more accurately measuring the time.

It should be noted that the optical pulse signal may be transmitted by other devices or may be emitted by the laser radar of the present invention. When the optical pulse signal is used by other devices (such as a laser-bound laser), the laser can communicate with the laser radar so that the laser radar can know the control power of the laser transmitter, the wavelength of the emitted laser, and the direction of the emission. At least one of and based on the control parameter Information such as the direction of obstacles is known.

It can be understood that the laser radar may include a laser transmitter, a transmission driver, etc., in addition to the respective devices shown in FIG. 1, FIG. 2 or FIG. 8, and the controller 140 may transmit a driving signal to the transmitting driver. The emission driver controls at least one of a control power of the laser transmitter, a wavelength of the emitted laser light, a transmission direction, and the like according to the received driving signal. The laser emitter is controlled by the emission driver and can emit optical pulse signals in a specific direction. After the optical pulse signal encounters the obstacle, the obstacle reflects the optical pulse signal, the photosensitive sensor 110 receives the reflected optical pulse signal, and converts the received optical pulse signal into an electrical signal. The electrical signal can be a voltage signal or a current signal.

Referring to FIG. 10, FIG. 10 is a schematic flowchart diagram of a time measurement method based on laser radar according to an embodiment of the present invention. It should be noted that although the signal processing method disclosed in the method embodiment can be implemented based on the laser radar shown in FIG. 1, FIG. 2 or FIG. 8, the above-described example laser radar does not constitute the signal processing method disclosed in the method embodiment of the present invention. The only limit. The signal processing method can include the following steps:

Step S1010: receiving the received light pulse signal through the photosensitive sensor, and converting the optical pulse signal into an electrical signal.

Step S1020: Perform an amplification operation on the electrical signal.

Step S1030: Adjust the gain of the photosensitive sensor, or adjust the preset threshold of the comparison operation so that the noise signal is lower than the preset threshold; the noise signal is a noise signal included in the amplified electrical signal.

It can be understood that, after the laser radar adjusts the gain of the photosensor, the laser radar can discard the current electrical signal, re-receive the received optical pulse signal through the photosensitive sensor, and convert the optical pulse signal into an electrical signal, and execute step S1040.

Step S1040: Comparing the electrical signal after the amplification operation with a preset threshold, and extracting time information corresponding to the electrical signal.

It can be understood that after the step S1040, the laser radar can also calculate the distance information corresponding to the time information and generate an image according to the distance information according to the time information, which is not limited by the present invention.

Please refer to the principle of avoiding noise signal trigger comparison circuit described in FIG. 3 and FIG. 4 above. Lidar can be used to prevent the noise signal from being triggered to a preset threshold in two ways. Method 1: By adjusting the preset threshold of the comparison circuit, that is, the preset threshold of the comparator, when the preset threshold of the comparison circuit is lower than the noise signal When the intensity is increased, the preset threshold is raised to prevent the noise signal from being triggered to the preset threshold. Method 2: Adjust the intensity of the electrical signal by adjusting the gain of the photosensitive sensor (such as APD), so that the electrical signal input from the amplifying circuit, that is, the intensity of the noise signal in the amplified electrical signal is lower than a preset threshold.

Optionally, an implementation manner of the lidar adjusting the preset threshold of the comparison operation may be: the lidar adjusts the preset threshold according to the intensity of the noise signal, so that the preset threshold is smaller than the intensity of the noise signal, and the wide dynamic light pulse can be realized. Under the signal, the preset threshold of the comparison circuit is dynamically adjusted according to the intensity of the noise signal in the electrical signal after the amplification operation.

Optionally, another implementation manner of the lidar adjusting the preset threshold of the comparison operation may be: the lidar adjusts the preset threshold according to the intensity of the noise signal, so that the preset threshold is higher than the noise signal and the preset threshold and the noise signal are The difference between the maximum values is not greater than the preset value, and the laser radar determines the most suitable preset threshold according to the strength of the noise signal, and minimizes the preset threshold when the preset threshold is greater than the noise signal, so that the comparison algorithm extracts The time information is closer to the real time when the electrical signal after the amplification operation traverses the comparison circuit that provides the comparison algorithm, and avoids the error caused by the variation of the signal amplitude on the acquisition of the time information, and the accuracy of the time measurement is high.

Alternatively, one embodiment of the lidar adjusting the gain of the photosensor may be that the controller may also determine the operating voltage of the photosensor based on the intensity of the noise signal. It can be understood that the large noise signal corresponds to a smaller operating voltage, and conversely, the first noise signal corresponds to a higher operating voltage.

For a specific implementation manner of adjusting the preset threshold, refer to the implementation manner of adjusting the preset threshold shown in FIG. 6 or FIG. 7 in the foregoing apparatus embodiment; and adjusting the gain of the photosensitive sensor, refer to the foregoing device embodiment. The implementation of adjusting the gain of the photosensor shown in FIG. 8 or FIG. 9 is not described in the present invention.

In the embodiment of the present invention, step S1030 may include: acquiring and comparing the intensity of the optical noise signal and the intensity of the electronic noise signal by the laser radar; and adjusting the preset of the comparison operation when the intensity of the optical noise signal is less than the intensity of the electronic noise signal The threshold is such that the noise signal is below a predetermined threshold; when the intensity of the optical noise signal is greater than the intensity of the electronic noise signal, the lidar adjusts the gain of the photosensor such that the noise signal is below a predetermined threshold.

It can be understood that for a given electronic device, the intensity of electronic noise is relatively stable, while optical noise The intensity of the light is greatly affected by the environment. The higher the light intensity in the environment, the higher the intensity of the light noise. Therefore, the intensity of the noise signal can be measured to characterize the intensity of the optical noise.

In the embodiment of the present invention, step S1030 may include: acquiring, by the laser radar, the intensity of the noise signal in the electrical signal after the amplification operation; when the intensity of the noise signal is less than the preset noise threshold, the laser radar adjusts the preset threshold of the comparison operation, so that The noise signal is lower than a preset threshold; when the intensity of the noise signal is greater than the preset noise threshold, the lidar adjusts the gain of the photosensor such that the noise signal is lower than a preset threshold.

In the embodiment of the present invention, after step S1020, before step S1030; the method further includes: the laser radar determines whether the noise signal is higher than a preset threshold; when the noise signal is higher than the preset threshold, the laser radar performs step S1030; otherwise, the laser The radar does not perform the adjustment of the gain of the photosensor or the preset threshold of the circuit, and step S1040 is performed.

The first implementation manner in which the laser radar determines whether the noise signal is higher than a preset threshold may be: the laser radar acquires the random noise number in the initial image generated by the laser radar, and determines whether the random noise number is higher than the preset noise threshold. The initial image is generated by the laser radar according to the electrical signal after the amplification operation and the preset threshold before the adjustment. If the random noise number is higher than the preset noise threshold, the noise signal is higher than the preset threshold, and the laser radar can be executed. Step S1030; otherwise, the laser radar does not perform the adjustment of the gain of the photosensor or the preset threshold of the circuit, and step S1040 is performed.

The second implementation manner in which the laser radar determines whether the noise signal is higher than a preset threshold may be: the laser radar detects the power information of the noise signal in a preset frequency range, and if the power information exceeds the preset power threshold, the noise signal is determined to be higher than The preset threshold value, the laser radar can perform step S1030, otherwise, the laser radar does not perform the adjustment of the gain of the photosensitive sensor or the preset threshold of the circuit, and step S1040 is performed.

The third embodiment in which the laser radar determines whether the noise signal is higher than a preset threshold may be: the laser radar may include a plurality of comparators and a plurality of TDCs, wherein the TDC is connected to the comparators one by one, and the laser radar will be amplified. The electrical signal is compared with the thresholds of the plurality of comparators, and the time information of the plurality of TDCs is extracted, and the second time information corresponding to the first time information corresponding to the preset threshold and the first threshold is calculated and compared, where The preset threshold is smaller than the first threshold. If the difference between the first time information and the second time information is a random value, and the difference between the first time information and the second time information is greater than a preset time threshold, determining that the noise signal is higher than the preset Threshold. The laser radar can perform step S1030. Otherwise, the laser radar does not perform the gain of the photosensor or the adjustment of the preset threshold of the circuit, and the steps are performed. S1040.

Optionally, before determining whether the noise signal is higher than the preset threshold, before adjusting the preset threshold of the comparison operation, the method further includes: selecting a threshold value that is higher than a minimum value of the noise signal as a preset threshold, and further acquiring the noise higher than the noise. The minimum threshold in the signal and the electrical signal after the amplification operation pass through the time information output by the comparison circuit, and then the preset threshold is minimized under the premise that the preset threshold is greater than the noise signal, so that the time information extracted by the comparison algorithm is closer to the amplification operation. The real time of the subsequent electrical signal acquisition avoids the error caused by the change of the signal amplitude and the acquisition of the time information, and the accuracy of the time measurement is high.

Optionally, when the laser radar includes a plurality of comparators and a plurality of TDCs, and the TDCs are connected in one-to-one correspondence with the comparators, the thresholds of the plurality of comparators may be the same, and the step S1040 may include: the lasers will amplify the calculated electricity The signal is compared with the thresholds of the plurality of comparators, and the time information measured by the plurality of TDCs is extracted (for example, t1, t2, t3, t4, and t5); and the electrical signals are calculated according to the time information measured by the plurality of TDCs. The time information may be calculated by taking the average value of t1, t2, t3, t4, and t5 as the time information corresponding to the electrical signal.

Optionally, when the laser radar includes a plurality of comparators and a plurality of TDCs, and the TDCs are connected in one-to-one correspondence with the comparators, the thresholds of the plurality of comparators may be different, and step S1040 may include: the lasers will amplify the calculated power The signal is compared with the thresholds of the plurality of comparators, and the time information corresponding to the plurality of comparators is measured by the plurality of TDCs, for example, (v1, t1), (v2, t3), (v3, t3) And (v4, t4), (v5, t5), and further fitting the waveform of the electrical signal after the amplification operation according to the time information measured by the plurality of TDCs, and calculating the time information corresponding to the electrical signal according to the fitted waveform, Referring to FIG. 5, T0 can be regarded as an electrical signal corresponding time information.

In the embodiment of the present invention, the laser radar receives the received light pulse signal through the photosensitive sensor, converts the optical pulse signal into an electrical signal, performs an amplification operation on the electrical signal, adjusts the gain of the photosensitive sensor, or adjusts the preset threshold of the comparison operation to The noise signal is lower than a preset threshold; the noise signal is a noise signal included in the electrical signal after the amplification operation, and the electrical signal after the amplification operation is compared with a preset threshold, and time information corresponding to the electrical signal is extracted, Further, when the intensity of the noise signal exceeds a preset threshold, the noise signal triggers distortion of the measured time information caused by the comparison circuit.

The technical terms used in the embodiments of the present invention are only intended to illustrate specific embodiments and are not intended to limit the invention. In the present disclosure, the singular forms "a", "the" Further, the use of "including" and / or "comprising", in the specification, is used to mean the presence of the features, the whole, the steps, the operation, the elements and/or the components, but does not exclude the presence or addition of one or more Other features, integers, steps, operations, components and/or components.

The corresponding structures, materials, acts, and equivalents of the elements, and the equivalents of the functional elements, if any, are intended to include any structure, material, or action that is used to perform the function. The description of the present invention has been presented for purposes of illustration and description. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention. The embodiments described in the present invention are able to better understand the principles and practical applications of the present invention, and may be understood by those of ordinary skill in the art.

The flowcharts described in the present invention are merely one embodiment, and various modifications may be made to the drawings or the steps of the present invention without departing from the spirit of the invention. For example, these steps can be performed in a different order, or some steps can be added, deleted, or modified. A person skilled in the art can understand that all or part of the process of implementing the above embodiments, and equivalent changes made according to the claims of the present invention, still fall within the scope of the invention.

Claims

A laser radar, comprising: a photosensitive sensor, an amplifying circuit, a comparing circuit, and a controller; wherein

The photosensitive sensor is configured to receive an optical pulse signal, and convert the optical pulse signal into an electrical signal, and output the electrical signal to the amplifying circuit;

The amplifying circuit is configured to amplify an electrical signal input from the photosensitive sensor, and output the amplified electrical signal to the comparison circuit;

The comparison circuit is configured to compare an electrical signal input from the amplifying circuit with a preset threshold, and extract time information corresponding to the electrical signal;

The controller is configured to adjust a gain of the photosensor or adjust a preset threshold of the comparison circuit such that the noise signal is lower than the preset threshold.
A laser radar according to claim 1, wherein said comparison circuit comprises at least one comparator, said first input of said comparator for receiving an electrical signal input from said amplifying circuit, said comparator The second input end is configured to receive the preset threshold, and the output end of the comparator is configured to output a result of the comparison operation, wherein the result of the comparison operation includes time information corresponding to the electrical signal.
A laser radar according to claim 2, wherein said comparison circuit further comprises a time to digital converter, said time to digital converter being electrically coupled to an output of said comparator for output according to said comparator As a result of the comparison operation, time information corresponding to the electrical signal is extracted.
The laser radar according to claim 1, wherein the controller is further configured to: determine a preset threshold according to an intensity of the noise signal, such that the preset threshold is higher than the noise signal and the preset threshold The difference from the maximum value of the noise signal is not greater than a preset value.
A laser radar according to claim 2, wherein said laser radar further comprises a number And a mode converter, wherein the controller is connected to the second input end of the comparator through the digital-to-analog converter, and adjusts a preset of the comparison circuit by controlling a magnitude of an output voltage of the digital-to-analog converter Threshold.
The laser radar according to claim 2, wherein said laser radar further comprises a comparison threshold adjustment circuit, said comparison threshold adjustment circuit comprising a plurality of resistors, one end of said plurality of resistors being commonly connected to said comparator a second input terminal, the plurality of voltage signals being input to the other end of the plurality of resistors for providing the preset threshold to the second input of the comparator through the plurality of resistors, by adjusting the a plurality of resistors are configured to adjust the predetermined threshold input to the second input of the comparison circuit.
The laser radar according to claim 1, wherein said laser radar further comprises a power management circuit, said power management circuit being electrically connected to said controller and said photosensor, said power management circuit for The photosensor provides an operating voltage, and the controller adjusts the gain of the photosensor by controlling the power management circuit to change the operating voltage.
A laser radar according to claim 7, wherein said photosensitive sensor comprises an avalanche photodiode, said cathode of said avalanche photodiode being electrically connected to said power management circuit for obtaining an operating voltage from said power management circuit An anode of the avalanche photodiode is coupled to an input end of the amplifying circuit, the avalanche photodiode is configured to receive an optical pulse signal, and convert the optical pulse signal into an electrical signal, and output the electrical signal to The amplifying circuit.
The laser radar according to any one of claims 1 to 6, wherein the noise signal comprises an optical noise signal and an electronic noise signal, and the controller is further configured to acquire and compare the intensity of the optical noise signal and The intensity of the electronic noise signal, and when the intensity of the optical noise signal is less than the intensity of the electronic noise signal, adjusting a preset threshold of the comparison circuit such that the noise signal is lower than the preset threshold .
The laser radar according to any one of claims 1 to 6, wherein the controller is further configured to acquire an intensity of the noise signal, when the intensity of the noise signal is less than a preset noise threshold, Adjusting a preset threshold of the comparison circuit such that the noise signal is lower than the preset threshold.
The laser radar according to any one of claims 1 to 7, wherein the noise signal comprises an optical noise signal and an electronic noise signal, and the controller is further configured to acquire and compare the optical noise signal. An intensity and an intensity of the electronic noise signal, and when the intensity of the optical noise signal is greater than the intensity of the electronic noise signal, adjusting a gain of the photosensor such that the noise signal is lower than the predetermined threshold .
The laser radar according to any one of claims 1 to 7, wherein the controller is further configured to acquire an intensity of the noise signal, when an intensity of the noise signal is greater than a preset noise threshold, The gain of the photosensor is adjusted such that the noise signal is below the predetermined threshold.
The laser radar according to any one of claims 1 to 8, wherein the controller is further configured to determine whether the noise signal is higher than the preset threshold.
The laser radar of claim 13 wherein said controller is further configured to:

Obtaining a random noise number in the initial image generated by the laser radar, and determining whether the random noise number is higher than a preset noise number threshold; the initial image is an electrical signal input by the controller according to the slave amplification circuit And generating an initial image by using a preset threshold before adjustment;

And if the random noise number is higher than a preset noise number threshold, determining that the noise signal is higher than the preset threshold.
A laser radar according to claim 13, wherein said laser radar further comprises a root mean square detector, said controller being electrically connected to said amplifying circuit via said root mean square detector for detecting a Decoding power information of the noise signal in a preset frequency range, and outputting the power information to the controller, the controller is further configured to:

Determining whether the power information input by the rms detector exceeds a preset power threshold;

And if the power information exceeds the preset power threshold, determining that the noise signal is higher than the preset threshold.
A laser radar according to claim 13, wherein said comparison circuit comprises a plurality of comparators and a plurality of Time-to-Digital Converters (TDCs), said comparators and said time number The converters are connected in one-to-one correspondence, the first input ends of the plurality of comparators are configured to receive the electrical signals input from the amplifying circuit, and the second input ends of the plurality of comparators are electrically connected to the controller, Respectively for receiving a threshold; the outputs of the plurality of comparators are respectively electrically connected to the controller through a time-to-digital converter connected in one-to-one correspondence with the plurality of comparators, the comparators to the time number The converter outputs a comparison result, the time-to-digital converter measuring time information according to the comparison result and outputting the time information to the controller; the controller is further configured to:

Calculating and comparing second time information corresponding to the first time information of the comparator of the first threshold of the plurality of comparators and the comparator of the second threshold; wherein the first threshold is smaller than the second threshold;

If the difference between the first time information and the second time information is a random value, and the difference between the first time information and the second time information is greater than a preset time threshold, determining that the noise signal is higher than The first threshold.
The laser radar of claim 16 wherein said controller is further configured to:

A threshold value that is the smallest of the thresholds higher than the noise signal is selected as the preset threshold.
The laser radar according to claim 16, wherein the controller is further configured to: fit a waveform of an electrical signal input to the comparator according to time information measured by a plurality of time-to-digital converters, according to the The combined waveform calculates the time information corresponding to the electrical signal.
A time measurement method based on laser radar, characterized in that it comprises:

Receiving a received optical pulse signal through a photosensor, and converting the optical pulse signal into an electrical signal;

Amplifying the electrical signal;

Adjusting a gain of the photosensor, or adjusting a preset threshold of the comparison operation, so that the noise signal is lower than the preset threshold; the noise signal is a noise signal included in the amplified electrical signal;

And comparing the amplified electrical signal with the preset threshold, and extracting time information corresponding to the electrical signal.
The method according to claim 19, wherein the adjusting the preset threshold of the comparison operation comprises: determining a preset threshold according to an intensity of the noise signal, such that the preset threshold is higher than the noise signal and the pre- It is assumed that the difference between the threshold and the maximum value of the noise signal is not greater than a preset value.
A method according to claim 19 or 20, wherein said noise signal comprises an optical noise signal and an electronic noise signal; said adjusting said gain of said photosensor or adjusting a preset threshold of the comparison operation to cause noise The signal below the preset threshold includes:

Acquiring and comparing the intensity of the optical noise signal and the strength of the electronic noise signal;

When the intensity of the optical noise signal is less than the intensity of the electronic noise signal, adjusting a preset threshold of the comparison operation such that the noise signal is lower than the preset threshold;

When the intensity of the optical noise signal is greater than the intensity of the electronic noise signal, the gain of the photosensor is adjusted such that the noise signal is lower than the preset threshold.
The method according to claim 19 or 20, wherein the adjusting the gain of the photosensor or adjusting the preset threshold of the comparison operation such that the noise signal is lower than the preset threshold comprises:

Obtaining the intensity of the noise signal in the electrical signal after the amplification operation;

And adjusting, when the intensity of the noise signal is less than a preset noise threshold, a preset threshold of the comparison operation, so that the noise signal is lower than the preset threshold;

When the intensity of the noise signal is greater than a preset noise threshold, the gain of the photosensor is adjusted such that the noise signal is lower than the preset threshold.
The method according to claim 19 or 20, wherein after said amplifying the electrical signal, said adjusting said gain of said photosensor or adjusting a preset threshold of a comparison operation; said method Also includes:

Determining whether the noise signal is higher than the preset threshold;

When the noise signal is higher than the preset threshold, the step of adjusting the gain of the photosensor or adjusting the preset threshold of the comparison operation is performed.
The method of claim 23, wherein the determining whether the noise signal is higher than the preset threshold comprises:

Obtaining a random noise number in an initial image generated by the laser radar, and determining whether the random noise number is higher than a preset noise number threshold; the initial image is an electrical signal of the laser radar according to the amplification operation and before adjusting Generated by a preset threshold;

And if the random noise number is higher than a preset noise number threshold, determining that the noise signal is higher than the preset threshold.
The method of claim 23, wherein the determining whether the noise signal is higher than the preset threshold comprises:

Detecting power information of the noise signal within a preset frequency range;

And if the power information exceeds the preset power threshold, determining that the noise signal is higher than the preset threshold.
The method according to claim 23, wherein the laser radar comprises a plurality of comparators and a plurality of time-to-digital converters, said comparators being connected in one-to-one correspondence with said time-to-digital converter, said determining said noise Whether the signal is higher than the preset threshold includes:

Comparing the amplified electrical signal with a threshold of the plurality of comparators, and measuring time information corresponding to the plurality of comparators by the plurality of time-to-digital converters;

Calculating and comparing the second time information corresponding to the first time information of the comparator corresponding to the preset threshold and the comparator of the first threshold; wherein the preset threshold is smaller than the first threshold;

If the difference between the first time information and the second time information is a random value, and the difference between the first time information and the second time information is greater than a preset time threshold, determining that the noise signal is higher than The preset threshold.
The method of claim 26, wherein determining whether the noise signal is high After the preset threshold, before the adjusting the preset threshold of the comparison operation, the method further includes: selecting a threshold that is lower than a threshold of the noise signal as the preset threshold.
The method of claim 26, wherein the comparing the electrical signal after the amplification operation with the preset threshold and extracting time information corresponding to the electrical signal comprises:

Comparing the amplified electrical signal with a threshold of the plurality of comparators, and measuring time information corresponding to the plurality of comparators by the plurality of time digital converters;

And fitting, according to time information measured by the plurality of time-to-digital converters, a waveform of the electrical signal after the amplification operation, and calculating time information corresponding to the electrical signal according to the fitted waveform.