CN114594494B - Laser radar system and ambient light denoising method thereof - Google Patents
Laser radar system and ambient light denoising method thereof Download PDFInfo
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- CN114594494B CN114594494B CN202210034793.3A CN202210034793A CN114594494B CN 114594494 B CN114594494 B CN 114594494B CN 202210034793 A CN202210034793 A CN 202210034793A CN 114594494 B CN114594494 B CN 114594494B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
- G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/4802—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/495—Counter-measures or counter-counter-measures using electronic or electro-optical means
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- Radar, Positioning & Navigation (AREA)
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- Electromagnetism (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The present disclosure relates to an ambient light denoising method for a laser radar system, the method comprising: emitting laser pulses to a detection area; detecting the number of optical excitation signals generated by each pixel unit of the photodetector in a predetermined period of time during which the laser pulse is emitted; and determining the ambient light noise threshold value of each pixel unit according to the detected quantity of the optical excitation signals. The disclosure also relates to a lidar system and an electronic device.
Description
Technical Field
The present disclosure relates to the field of Advanced Driving Assistance Systems (ADAS) and autopilot systems, and more particularly to lidar technology applied in Advanced Driving Assistance Systems (ADAS) and autopilot systems.
Background
In advanced driving assistance systems and automatic driving systems, laser radars are widely used for measuring the spatial distance and reconstructing three-dimensional environment of the surrounding environment of a vehicle, and are important preconditions for realizing high-precision automatic driving control. Lidar is susceptible to interference from ambient light during use. In particular, in different scenes, such as sunny days, cloudy days, rainy days, nights, tunnels, haze and the like, ambient light has different influences on the detection capability of the laser radar. Therefore, the laser radar needs to set noise threshold values for different ambient lights of different scenes to overcome the influence of the ambient lights on the performance of the laser radar.
Prior art lidar typically uses a single preset threshold to remove ambient light noise. However, the external scene changes and the change range is difficult to determine, and even under the same scene, the light intensity of the ambient light corresponding to different detection angles and test distances is different. Therefore, it is difficult to accurately de-noise the external ambient light intensity by using a single threshold, which results in a large influence on the performance of the lidar.
Disclosure of Invention
Aiming at the defects of the prior art, the laser radar system is further improved, so that the laser radar has good use performance under various ambient light scenes.
In one aspect, an ambient light denoising method for a laser radar system is provided, the method including:
emitting laser pulses to a detection area;
detecting the number of optical excitation signals generated by each pixel unit of the photodetector in a predetermined period of time during which the laser pulse is emitted;
and determining the ambient light noise threshold of each pixel unit according to the detected quantity of the optical excitation signals.
Advantageously, the pixel cell is a single pixel on the photodetector.
Advantageously, the pixel cell comprises two or more pixels of a photodetector.
In another aspect, another method for denoising ambient light for a lidar system is provided, the method comprising:
acquiring the total quantity of optical excitation signals generated by a preset pixel unit of a photoelectric detector in a preset time period in the process of transmitting laser pulses to a detection area by a laser; and
and comparing the total quantity of the optical excitation signals with a noise threshold table to determine an ambient light noise threshold, wherein the noise threshold table comprises a plurality of thresholds, and each threshold has a preset quantity of the optical excitation signals.
Advantageously, the obtaining of the total amount of optical excitation signals of the predetermined pixel unit comprises:
setting the preset time interval to be composed of a plurality of time sequences, wherein each time sequence comprises a plurality of time units;
and recording the light excitation signal output of each time unit of a preset pixel unit of the photoelectric detector and accumulating the light excitation signals of all the time units in the time sequence to obtain the total light excitation signal amount.
Advantageously, there is a sequence time interval between two consecutive time sequences.
Advantageously, the predetermined pixel cell is a single pixel cell of the photodetector.
Advantageously, the predetermined pixel cell is two or more pixel cells of a photodetector.
Advantageously, the photodetector is a single photon avalanche diode chip.
In another aspect, a method for denoising ambient light for a lidar system is provided, the method comprising:
acquiring the total quantity of optical excitation signals generated by each pixel unit of the photoelectric detector in a preset time period in the process of transmitting laser pulses to the detection area by the laser; and
and comparing the total quantity of the light excitation signals with a noise threshold table, and determining the ambient light noise threshold value of each pixel unit, wherein the noise threshold table comprises a plurality of threshold values, and each threshold value has a preset quantity of the light excitation signals.
Advantageously, the obtaining of the total amount of optical excitation signals per pixel unit comprises:
setting the preset time period to be composed of a plurality of time sequences, wherein each time sequence comprises a plurality of time units;
and recording the light excitation signal output of each pixel unit in each time unit and counting to obtain the total amount of the light excitation signals.
Advantageously, there is a sequence time interval between two consecutive time sequences.
Advantageously, the photodetector is a single photon avalanche diode chip.
Advantageously, the pixel cell is a single pixel of the photodetector.
Advantageously, the pixel cell is two or more pixels of the photodetector.
In yet another aspect, there is provided a lidar system comprising:
a laser arranged to emit laser pulses towards the detection area;
a photodetector arranged to generate a light-activated signal upon receipt of a photon signal;
the collector is set to count the total quantity of optical excitation signals generated by each pixel unit of the photoelectric detector in a preset time period;
a comparator configured to receive the total amount of optical excitation signals and compare it to a noise threshold table to determine an ambient light noise threshold, wherein the noise threshold table comprises a plurality of thresholds, each threshold having a predetermined number of optical excitation signals.
Advantageously, the collector is further arranged to:
recording the preset time period, wherein the preset time period consists of a plurality of time sequences, and each time sequence comprises a plurality of time units;
and recording the light excitation signal output of each pixel unit in each time unit and counting to obtain the total amount of the light excitation signals.
Advantageously, the pixel cell of the photodetector is a single pixel of the photodetector.
Advantageously, the pixel cells of the photodetector are two or more pixels of the photodetector.
In yet another aspect, an electronic device is provided, including: at least one processor and a memory communicatively coupled to the at least one processor, the memory storing instructions executable by the at least one processor to perform the methods of the present disclosure.
Drawings
Further details and advantages of the present disclosure are described in further detail below with reference to the attached drawing figures, wherein:
FIG. 1 illustrates a block diagram of a lidar system in accordance with one or more embodiments;
FIG. 2 illustrates a flow diagram of an ambient light denoising method for a lidar system, in accordance with one or more embodiments;
FIG. 3 illustrates a schematic pixel diagram of a Single-Photon Avalanche Diode (SPAD) sensor employed in accordance with one or more embodiments;
FIG. 4 illustrates another ambient light denoising method for a lidar system in accordance with one or more embodiments;
FIG. 5 illustrates a schematic diagram of the steps applied to obtain the number of photo-excitation signals for a predetermined pixel element in accordance with one or more embodiments;
FIG. 6 illustrates yet another ambient light denoising method for a lidar system in accordance with one or more embodiments.
Detailed Description
Fig. 1 shows a block diagram of a lidar system according to one or more embodiments of the present disclosure, showing only some of the constituent elements, electronics, or functional modules of the lidar system. Those skilled in the art will understand that other related units, devices or modules are required or may be added to the system in order to realize the present disclosure after understanding the principle of the present disclosure.
The laser radar system comprises a laser 1 and a controller 2, wherein the laser 1 emits laser pulses to a detection area 3 under the control of the controller 2, and the laser pulses form diffuse reflection echoes on the surface of the detection area in the form of laser beams, and the diffuse reflection echoes are detected by the laser radar system so as to realize functions such as distance measurement of the detection area.
The laser 1 may be any form of laser known in the art, such as a semiconductor laser, e.g., a distributed feedback laser or a vertical cavity surface emitting laser. In one or more embodiments, the controller sends a pulse signal to the laser according to a predetermined time sequence, and the laser emits laser pulses to the detection area after receiving the pulse signal.
The controller 2 is used for sending a working instruction, such as a pulse signal, to the laser to realize the functions of turning on and off the laser, and adjusting the laser pulse width, repetition frequency, energy parameters and the like. The controller can be a special electronic control device, and the control function can also be realized by a central processing unit.
The lidar system further comprises a photodetector 4 arranged to generate a light excitation signal upon reception of an external light wave. The photodetector 4 is, for example, a CCD photosensor, a CMOS sensor, a PD photodiode, an APD avalanche diode, an SPAD single photon avalanche diode, or the like. In one or more embodiments, SPAD chips (single photon avalanche diodes) are employed as the photodetection sensors. The SPAD chip is a digital chip, and has a pixel array composed of a plurality of pixels, and each pixel is in an avalanche state (in some special scenes, the magnification is not the maximum state, and the geiger mode can be a linear magnification state) under an external high voltage difference. In an avalanche state, when receiving a photon signal of a laser diffuse reflection echo or external environment light, the pixel unit is excited by the photon signal to discharge, and the output value is 1, if the laser diffuse reflection echo or the external environment light is not received, the pixel unit is not excited, and no value or 0 is output.
The lidar system further comprises a collector 5 arranged to collect emission time information of the laser and to count a total amount of photo-excitation signals occurring at pixel units of the photodetector during a preset period of time. In one or more embodiments, the collector 5 includes a TDC circuit (Time-Distance converter), which is connected to the SPAD chip to determine a Time difference between laser emission and detection of a laser diffuse reflection echo by the SPAD photodetector, so as to calculate a Distance from a detection area to the lidar, where the calculation formula is: s = speed of light × time difference/2. The TDC circuit directly calculates the distance between the laser radar system and the detection area by the time difference between the laser pulse transmission and the receiving of the diffuse reflection echo, saves the signal change flow of optical signals, analog signals and digital signals required by using other photosensitive elements, and has higher execution efficiency.
The lidar system further comprises a comparator 6 which receives the total amount of light excitation signals generated by predetermined pixel units of the photodetector and determines an ambient light noise threshold by comparing the total amount of light excitation signals with a preset noise threshold table. The noise threshold table includes a plurality of thresholds, each threshold having a predetermined number of optical excitation signals.
The setting method of the noise threshold value table comprises the following steps: the laser radar is completely placed in different scenes, such as at night, cloudy days, rainy days, cloudy days, sunny days and the like, and is tested in comparison with a remote place, so that the total excitation quantity of a single pixel in the obtained optical detector is used as a standard to set a noise threshold value.
Another method for setting the noise threshold table is to set different illumination intensities in a laboratory, collect the total excitation amount of a single pixel, and set a corresponding noise threshold.
The lidar system further comprises a memory 7, e.g. a non-volatile computer-readable storage medium, for storing non-volatile software programs, non-volatile computer-executable programs and modules, etc. Non-volatile software programs, instructions, modules, etc. stored in the memory are executed by the controller or other processor to perform various functional applications of the system and data processing. The memory may include a program storage area and a data storage area, wherein the program storage area may store, for example, an operating system, an application program required for at least one function, and the like; the data storage area may store, for example, a list of options, a noise threshold table, and the like. In some embodiments, the memory may include memory located remotely from the processor, and these remote memories may be connected to the external device through a network, examples of which include, but are not limited to, the internet, an intranet, a local area network, a mobile communications network, and combinations thereof.
FIG. 2 illustrates a method for ambient light denoising for a lidar system, in accordance with one or more embodiments, the method comprising:
s101: a laser pulse is emitted towards the detection area.
The laser pulse may be a laser pulse emitted separately for detecting ambient light or a laser pulse emitted by the laser radar during actual detection. In one or more embodiments, a laser of the lidar system, under control of the controller, emits laser pulses to the detection region that form diffusely reflected echoes in the form of a laser beam at the surface of the detection region and are received by a photodetector to generate optical excitation signals. For example, according to an operation command from a controller of the laser radar system, the laser starts to operate at a predetermined time, and emits a laser beam having predetermined parameters of pulse width, repetition rate, energy, and the like.
S102: the amount of photo-excitation signal generated per pixel cell of the photo-detector during a predetermined period of time during which the laser pulse is emitted is detected.
The photodetector is generally provided with a plurality of pixel cells. In one example, the pixel cells are arranged, for example, as a single pixel on a photodetector. In another example, the pixel cells are arranged, for example, as two or more pixels on a photodetector. The method in fig. 2 is to acquire the optical excitation signal of each pixel of the photodetector, for example, by an acquisition device, and count the number of optical excitation signals occurring in a predetermined period of time in a plurality of pixels of a group imaging pixel unit.
Fig. 3 shows a schematic pixel diagram of a specific photodetector, such as a SPAD sensor, applied according to one or more embodiments, the sensor is provided with a pixel array (20 × 10) including 20 pixel units 42, each including 10 pixels 41, each pixel, when receiving a photon signal of a laser diffuse reflection echo or external environment light, excites a discharge output by the photon signal, and outputs a value "1", if not excited, outputs no value or outputs a value "0". As shown in the figure, 10 pixels in the pixel unit are lasered by the optical signal for a predetermined period of time, and the collector collects the amount of laser light in each time unit for each pixel. Other pixel cells are also tested in the same manner to determine the total number of photoexcitation signals for a single pixel within a predetermined time period.
S103: and determining the ambient light noise threshold value of each pixel unit according to the detected quantity of the optical excitation signals.
In one or more embodiments, the comparator of the lidar system receives the total amount of the optical excitation signal for each pixel cell and compares the total amount of the optical excitation signal with a preset noise threshold table to determine the ambient light noise threshold for the detection region corresponding to each pixel cell. A plurality of threshold values are preset in the noise threshold value table, and each threshold value has a preset number of light excitation signals.
For example, N thresholds are preset in the noise threshold table, and the preset number of light excitations of each threshold is K1, K2, \ 8230 \ 8230;, kn, respectively, and the preset number of light excitations may be a specific numerical value or a numerical range. The number of optical excitation signals of each pixel unit is compared with a noise threshold table to determine the specific threshold value in which the optical excitation signals fall.
Firstly, the laser radar is completely placed in different scenes, such as at night, in rainy days, in cloudy days, in sunny days and the like, remote testing is performed, the total excitation quantity of the optical detector is obtained, all pixels of the laser radar detector array can measure the total excitation quantity within preset time, the total excitation quantity is averaged, a group of data is obtained, for example, the excitation quantity measured at night is 1000, the total excitation quantity measured at rainy days is 2000, the total excitation quantity measured at cloudy days is 3000, in cloudy days is 5000, and the total excitation quantity measured at sunny days is 8000, K1 is set to 2000, K2 is set to 3000, K3 is set to 5000, and K4 is set to 8000, and the data is recorded into a memory, and in the actual test of the laser radar, the environment measured by each pixel is judged by comparing the quantity of the optical excitation signals of each pixel unit with the preset K value.
The preset value method is also used for setting different illuminances according to the illuminance of the environment, setting different illuminances to 500Lux,10000Lux,20000Lux and 100000Lux in an illuminance standard laboratory, counting the excitation quantity of each pixel of a pixel unit of the laser radar, and setting different intervals of illuminances and different numbers of illuminance levels according to the actual demand condition so as to set different intervals of environment thresholds and threshold numbers.
FIG. 4 illustrates another ambient light denoising method for a lidar system, in accordance with one or more embodiments, the method comprising:
s201: the total amount of optical excitation signals generated by a predetermined pixel unit of the photoelectric detector in a preset time period when the laser emits laser pulses to the detection area is obtained.
The predetermined pixel unit is provided, for example, as a single pixel on a photodetector, or includes two or more pixels on the photodetector.
The preset time period is composed of a plurality of time series, and each time series comprises a plurality of time units. The total quantity of the optical excitation signals is obtained by recording the optical excitation signal output of a preset pixel unit of the photoelectric detector in each time unit and counting. In one example, there is a sequence time interval between two consecutive time sequences.
In this step, after the laser is started to emit laser pulses to the detection area by the controller, the laser pulses form diffuse reflection echoes on the surface of the detection area in the form of laser beams, and the echoes and other ambient light are received by the photoelectric detector to generate optical excitation signals. Meanwhile, for example, the photo-excitation signal of a predetermined pixel unit of the photo-detector is monitored by using a collector, and the number of the photo-excitation signals of the predetermined pixel unit in a preset period is counted.
Fig. 5 illustrates a specific method for counting the number of optical excitation signals of a predetermined pixel unit in a preset time period according to one or more embodiments:
firstly, the controller sends a pulse signal to the laser, the laser emits the 1 st laser pulse to the test area, the TDC circuit starts to time, and every other time unit T unit Recording the output condition of the optical excitation signal of the predetermined pixel unit of the photoelectric detector in the time unit, wherein M time units are required in total and T is required sum And recording the output results of the optical excitation signals of M time units.
After that, the laser emits the 2 nd laser pulse to the detection area, the TDC circuit starts to time again, and every other time unit T unit Recording the output condition of the optical excitation signal of the predetermined pixel unit of the photoelectric detector in the time unit, wherein M time units are required in total and T is required sum And recording the output results of the optical excitation signals of M time units.
Then, after the laser emits N times of laser pulses, each pixel of the preset pixel unit is subjected to preset time interval N M T unit The number of the light excitation signals in the optical fiber is accumulated and is recorded as the total number K of the light excitation signals.
More specifically, the controller sends a pulse signal to the laser, the laser sends a 1 st laser pulse to the test area, the TDC circuit starts timing, the TDC circuit records the output condition of the optical excitation signal of a predetermined pixel unit of the photodetector in the time unit with a main frequency of 500MHz, that is, every other time unit of 2ns, the total time unit is 1000, 2 μ s is needed, and the output result of the optical excitation signal of 1000 time units is stored in a register, for example.
Then, the laser emits the 2 nd laser pulse to the detection area, the TDC circuit starts timing again, records the output condition of the optical excitation signal of the predetermined pixel unit of the photodetector in the time unit every 2ns, and the total time of 1000 time units takes 2 μ s, and stores the output result of the optical excitation signal of 1000 time units into a register, for example.
And repeating the previous steps until the laser emits 150 laser pulses, and accumulating the quantity of the optical excitation signals of each pixel of the preset pixel unit within 0.3ms of a preset time period to be recorded as the total quantity K of the optical excitation signals.
S202: and comparing the total quantity of the optical excitation signals with a noise threshold table to determine an ambient light noise threshold.
A plurality of threshold values are preset in the noise threshold value table, and each threshold value has a preset number of optical excitation signals. For example, N thresholds are preset in the noise threshold table, and the preset number of light excitations of each threshold is K1, K2, \ 8230 \ 8230;, kn, respectively, and the preset number of light excitations may be a specific numerical value or a numerical range. By comparing said predetermined pixel cells over a predetermined time period N M T unit The total amount K of the optical excitation signal in the optical excitation signal and a noise threshold table determine the specific threshold value in which the optical excitation signal falls.
For example, the comparator of the lidar system receives the total amount of the optical excitation signal of the predetermined pixel unit and compares the total amount with a preset noise threshold table to determine an ambient light noise threshold.
FIG. 6 illustrates yet another ambient light denoising method for a lidar system, according to one or more embodiments, comprising:
s301: and acquiring the total quantity of optical excitation signals generated by each pixel unit of the photoelectric detector in a preset time interval in the process of transmitting laser pulses to the detection area by the laser.
The photodetector of the laser system is provided with a plurality of pixel units, which may be provided as a single pixel, or as two or more pixels on the photodetector.
The preset time period is composed of a plurality of time series, and each time series comprises a plurality of time units. And recording the light excitation signal output of the pixel unit of the photoelectric detector in each time unit and counting to obtain the total amount of the light excitation signal. In one example, there is a sequence time interval between two consecutive time sequences.
In accordance with one or more embodiments, the laser pulse forms a diffuse reflection echo on the surface of the detection area in the form of a laser beam during a preset period of time when the laser emits the laser pulse to the detection area, and the echo and other ambient light are received by the photodetector to generate a light excitation signal. The optical excitation signal of each pixel unit of the photoelectric detector is monitored by using the collector, and the total amount of the optical excitation signal is obtained by counting the number of the optical excitation signals of each pixel unit in a preset unit.
S302: and comparing the total quantity of the optical excitation signals with a noise threshold table, and determining the ambient light noise threshold of each pixel unit.
In one or more embodiments, a comparator of the lidar system receives the total amount of optical excitation signal for each pixel cell of the photodetector and compares it to a preset noise threshold table to determine an ambient light noise threshold for each pixel cell. A plurality of threshold values are preset in the noise threshold value table, and each threshold value has a preset number of light excitation signals. For example, N thresholds are preset in the noise threshold table, the preset number of optical excitations for each threshold is K1, K2, \8230;, kn, respectively, and the preset number of optical excitations may be a specific number or a range of numbers. The specific threshold value in which the total amount of the optical excitation signal of each pixel unit falls is determined by comparing the total amount of the optical excitation signal with a noise threshold value table.
In one or more embodiments, the total output value is determined by recording, storing, reading and counting the output condition of the optical excitation signal of each pixel unit of the photoelectric detection unit in a preset time period, and a denoising threshold value is set for each pixel unit, so that the actual ambient light condition of the monitoring area is reflected more accurately, and the denoising of the whole ambient light determined by one pixel is avoided. Moreover, the ambient light noise point threshold value of each pixel can change along with the change of light intensity, and the timeliness and the accuracy of the laser radar ambient light noise removal are improved. In addition, different threshold levels are set, so that the threshold value of the ambient light noise point under different scenes can be better met. In addition, the method and the data for acquiring the data of the ambient light by the laser radar are the same as those for acquiring the detection distance of the laser radar, and the data are the same group of data, so that additional data acquisition work is not needed, and the test efficiency of the laser radar is improved.
Those skilled in the art will appreciate that all or part of the steps in the method for implementing the embodiments described above may be implemented by a program to instruct related hardware to execute the steps, where the program is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, etc.) or a processor to execute all or part of the steps of the method described in the embodiments of the present application. The storage medium includes: various media capable of storing program codes, such as a U disk, a removable hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.
Claims (11)
1. An ambient light denoising method for a lidar system, the method comprising:
acquiring the total quantity of light excitation signals generated by a preset pixel unit of a photoelectric detector in a preset time period in the process of transmitting laser pulses to a detection area by a laser; and
comparing the total amount of the light excitation signals with a noise threshold table to determine an ambient light noise threshold, wherein the noise threshold table comprises a plurality of thresholds, and each threshold has a preset number of light excitation signals;
wherein the obtaining of the total amount of the optical excitation signals of the predetermined pixel unit comprises:
setting the preset time period to be composed of a plurality of time sequences, wherein each time sequence comprises a plurality of time units, and a sequence time interval exists between two continuous time sequences; and
and recording the light excitation signal output of a preset pixel unit of the photoelectric detector in each time unit and accumulating the light excitation signals of all time units of the plurality of time sequences to obtain the total light excitation signal amount.
2. The ambient light denoising method of claim 1, wherein the predetermined pixel unit is a single pixel unit of a photodetector.
3. The ambient light denoising method of claim 1, wherein the predetermined pixel unit is two or more pixel units of a photodetector.
4. The ambient light denoising method of claim 1, wherein the photodetector is a single photon avalanche diode chip.
5. The ambient light denoising method of claim 1, wherein the predetermined pixel unit is each pixel unit of a photodetector.
6. The ambient light denoising method of any one of claims 2-5, wherein the pixel unit is a single pixel of the photodetector.
7. The ambient light denoising method according to any one of claims 2-5, wherein the pixel unit is two or more pixels of the photodetector.
8. A lidar system comprising:
a laser arranged to emit laser pulses towards the detection area;
a photodetector arranged to generate a light-activated signal upon receipt of a photon signal;
the device comprises a collector and a control unit, wherein the collector is set to count the total quantity of light excitation signals generated by a preset pixel unit of a photoelectric detector in a preset time period, the preset time period consists of a plurality of time sequences, each time sequence comprises a plurality of time units, and a sequence time interval exists between every two continuous time sequences, and the total quantity of the light excitation signals is the accumulation of the light excitation signals of the preset pixel unit of the photoelectric detector in all the time units of the time sequences;
a comparator configured to receive the total amount of optical excitation signals and compare the total amount of optical excitation signals with a noise threshold table to determine an ambient light noise threshold, wherein the noise threshold table includes a plurality of thresholds, each threshold having a predetermined number of optical excitation signals.
9. The lidar system of claim 8, wherein the pixel unit of the photodetector is a single pixel of the photodetector.
10. The lidar system of claim 8, wherein the pixel unit of the photodetector is two or more pixels of the photodetector.
11. An electronic device, comprising: at least one processor and a memory communicatively coupled to the at least one processor, the memory storing instructions executable by the at least one processor, wherein the instructions are executable by the at least one processor to perform the method of any of claims 1-7.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210034793.3A CN114594494B (en) | 2022-01-13 | 2022-01-13 | Laser radar system and ambient light denoising method thereof |
| PCT/CN2022/076490 WO2023133964A1 (en) | 2022-01-13 | 2022-02-16 | Laser radar system and ambient light denoising method therefor |
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| CN202210034793.3A CN114594494B (en) | 2022-01-13 | 2022-01-13 | Laser radar system and ambient light denoising method thereof |
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| US7157685B2 (en) * | 2004-04-12 | 2007-01-02 | Canesta, Inc. | Method and system to enhance differential dynamic range and signal/noise in CMOS range finding systems using differential sensors |
| WO2006086455A2 (en) * | 2005-02-08 | 2006-08-17 | Canesta, Inc. | Method and system to enhance differential dynamic range and signal/noise in cmos range finding systems using differential sensors |
| CN102692622B (en) * | 2012-05-28 | 2014-07-02 | 清华大学 | Laser detection method based on dense pulses |
| CN103698770A (en) * | 2013-12-11 | 2014-04-02 | 中国科学院长春光学精密机械与物理研究所 | Multi-channel laser echo time measurement system based on FPGA (Field Programmable Gate Array) chip |
| CN105607073A (en) * | 2015-12-18 | 2016-05-25 | 哈尔滨工业大学 | Photon-counting imaging laser radar for filtering noise in real time by adopting adjacent pixel element threshold value method |
| US10241198B2 (en) * | 2017-03-30 | 2019-03-26 | Luminar Technologies, Inc. | Lidar receiver calibration |
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| CN108304781B (en) * | 2017-12-29 | 2020-07-14 | 华中科技大学 | Area array Geiger APD laser imaging radar image preprocessing method |
| JP2019158693A (en) * | 2018-03-15 | 2019-09-19 | 株式会社リコー | Light reception device, object detection device, distance measurement device, moving body device, noise measurement method, object detection method, and distance measurement method |
| WO2020168489A1 (en) * | 2019-02-20 | 2020-08-27 | 深圳市大疆创新科技有限公司 | Ranging apparatus, ranging method, and mobile platform |
| CN109839639A (en) * | 2019-02-27 | 2019-06-04 | 宁波舜宇车载光学技术有限公司 | Laser radar and the laser radar system and its detection method for reducing ambient light interference |
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