CN114594493A - Laser radar system and ambient light sensing method thereof - Google Patents
Laser radar system and ambient light sensing method thereof Download PDFInfo
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- CN114594493A CN114594493A CN202210034743.5A CN202210034743A CN114594493A CN 114594493 A CN114594493 A CN 114594493A CN 202210034743 A CN202210034743 A CN 202210034743A CN 114594493 A CN114594493 A CN 114594493A
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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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- Optical Radar Systems And Details Thereof (AREA)
Abstract
The present disclosure provides an ambient light sensing method for a lidar 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; the ambient light intensity of each pixel cell is determined from the number of detected optical excitation signals. The present disclosure also provides a laser radar 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 a three-dimensional environment of a vehicle surrounding environment, 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 adjust the parameter performance of the laser radar according to different ambient light intensities of different scenes so as to overcome the influence of ambient light on the performance of the laser radar.
Prior art lidar typically uses a single preset threshold to detect the external ambient light intensity. 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 interpret the external ambient light intensity using a single threshold, resulting in a large impact 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, there is provided an ambient light perception method for a lidar 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;
the ambient light intensity of each pixel cell is determined from the number of detected photo-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, there is provided another ambient light sensing 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
and comparing the total quantity of the light excitation signals with a light intensity threshold table to determine the level of the ambient light intensity, wherein the light intensity threshold table comprises a plurality of light intensity thresholds, and each light intensity threshold has a preset quantity of the light excitation signals and represents the corresponding level of the ambient light intensity.
Advantageously, the obtaining of the total amount of light 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
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 yet another aspect, there is provided a method for ambient light sensing for a lidar system, 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 light intensity threshold table to determine the ambient light intensity level of each pixel unit, wherein the light intensity threshold table comprises a plurality of light intensity thresholds, and each light intensity threshold has a preset quantity of the light excitation signals and represents the corresponding ambient light intensity level.
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 light excitation signals generated by each pixel unit of the photoelectric detector in a preset time period; and
a comparator arranged to receive the total amount of light excitation signals and to compare with a light intensity threshold table to determine an ambient light intensity level, wherein the light intensity threshold table comprises a plurality of threshold values, each threshold value having a predetermined number of light excitation signals and being indicative of a corresponding ambient light intensity level.
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
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, 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 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 sensing method for a lidar system in accordance with one or more embodiments;
FIG. 3 illustrates a pixel schematic of a Single-Photon Avalanche Diode (SPAD) sensor employed in accordance with one or more embodiments;
FIG. 4 illustrates another ambient light sensing 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 cell in accordance with one or more embodiments;
FIG. 6 illustrates yet another ambient light sensing 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 the figures in order to implement the present disclosure, after understanding the principles 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 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 parameter, 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, each of which is in an avalanche state (in some special scenes, the amplification factor is not maximum, and the geiger mode can be a linear amplification state). In the 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, and if not receiving the laser diffuse reflection echo or the external environment light, the pixel unit is not excited, and does not output any value or the output value is 0.
The lidar system further comprises a collector 5 configured to collect emission time information of the laser and count a total amount of optical excitation signals generated by pixel units of the photodetector during a preset time period. In one or more embodiments, the collector 5 includes a TDC circuit (Time-Distance Convert Time-Distance) 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 the detection area to the lidar, where the calculation formula is: s is the speed of light x 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 the ambient light intensity level by comparing the total amount of light excitation signals with a preset light intensity threshold table. The light intensity threshold table includes a plurality of thresholds, each threshold having a predetermined number of light excitation signals and representing a corresponding ambient light intensity level.
The setting method of the light intensity 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 light detector is obtained, and the light intensity threshold value is set by taking the total excitation quantity as a standard.
Another setting method of the light intensity threshold table of the light beam is to set different illumination intensities in a laboratory, collect the total excitation amount of a single pixel and set a corresponding light intensity threshold.
The lidar system also includes a memory 7, such as a non-volatile computer-readable storage medium, for storing non-volatile software programs, non-volatile computer-executable programs, modules, and the like. 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 table of light intensity thresholds, etc. 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 an ambient light sensing method 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 a laser pulse toward the detection region that forms a diffusely reflected echo at the surface of the detection region in the form of a laser beam and is received by a photodetector to generate an optical excitation signal. 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 number of optical excitation signals generated per pixel unit of the photodetector 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 units. 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 the laser 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: the ambient light intensity of each pixel cell is determined from the number of detected 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 with a preset light intensity threshold table to determine the ambient light intensity level at the location of the detection region corresponding to each pixel cell. A plurality of threshold values are preset in the light intensity threshold value table, and each threshold value has a preset quantity of light excitation signals so as to represent the corresponding ambient light intensity level.
For example, the light intensity threshold table presets N thresholds, and the preset number of light excitations of each threshold is K1, K2, … …, Kn, respectively, and the preset number of light excitations may be a specific number or a range of numbers. And determining the light intensity level received by each pixel cell by comparing the number of the light excitation signals of each pixel cell with a light intensity threshold table and determining the specific threshold value in which the number of the light excitation signals falls, wherein K1 is the weakest light intensity and Kn is the strongest light intensity.
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 in a 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 rain 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 of each pixel is interpreted by comparing the quantity of optical excitation signals of each pixel unit with a preset K value.
The preset value method is also used for setting according to the illumination of the environment, different illuminations are set in an illumination standard laboratory, the illuminations are respectively set to be 500Lux, 10000Lux, 20000Lux and 100000Lux, the excitation quantity of each pixel of a pixel unit of the laser radar is counted, and the illuminations at different intervals and the illumination levels of different quantities can be set according to the actual demand condition so as to set the environment threshold values and the threshold quantity at different intervals.
FIG. 4 illustrates another ambient light sensing method for a lidar system, in accordance with one or more embodiments, including:
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 sends 1 st laser pulse to the test area, the TDC circuit starts to time, and every other time unit TunitRecording 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 requiredsumAnd the output results of the optical excitation signals of the M time units are stored in a register, for example.
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 TunitRecording 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 requiredsumAnd the output results of the optical excitation signals of the M time units are stored in a register, for example.
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 TunitInternal lightThe number of excitation signals is accumulated and is recorded as the total number of optical excitation signals K.
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, the total time of 1000 time units is 2 μ s, and the output result of the optical excitation signal of 1000 time units is stored in 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 light excitation signals with a light intensity threshold table to determine the intensity level of the environment light.
A plurality of threshold values are preset in the light intensity threshold value table, and each threshold value has a preset quantity of light excitation signals so as to represent the corresponding ambient light intensity level. For example, the light intensity threshold table presets N thresholds, the preset number of light excitations of each threshold is K1, K2, … …, Kn, respectively, and the preset number of light excitations may be a specific value or a range of values. By comparing said predetermined pixel cells over a predetermined time period N M TunitThe total amount of the light excitation signal K and the light intensity threshold table in the table determine the specific threshold value that it falls into, thereby determining the light intensity level received by the predetermined pixel, where K1 is the weakest light intensity and Kn is the strongest light intensity.
For example, a comparator of the lidar system receives the total amount of light excitation signals for the predetermined pixel element and compares it with a preset light intensity threshold table to determine the ambient light intensity level.
FIG. 6 illustrates yet another ambient light sensing method for a lidar system, in accordance with one or more embodiments, including:
s301: and acquiring the total quantity of optical excitation signals generated by each pixel unit of the photoelectric detector in a preset time interval during the process of transmitting the laser pulse 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 light intensity threshold value table to determine the ambient light intensity level of each pixel unit.
In one or more embodiments, the comparator of the lidar system receives the total amount of light excitation signal for each pixel cell of the photodetector and compares it to a preset light intensity threshold table to determine the ambient light intensity level for each pixel cell. A plurality of threshold values are preset in the light intensity threshold value table, and each threshold value has a preset quantity of light excitation signals so as to represent the corresponding ambient light intensity level. For example, the light intensity threshold table presets N thresholds, each threshold presets K1, K2, … …, Kn respectively, and the preset number of light excitations may be a specific number or a range of numbers. And determining the light intensity level received by the pixel by comparing the total light excitation signal amount of each pixel unit with a light intensity threshold table and determining the specific threshold value which falls into the total light excitation signal amount, wherein K1 is the weakest light intensity and Kn is the strongest light intensity.
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 the ambient light intensity of each pixel unit is respectively judged, so that the actual ambient light intensity of the monitoring area is reflected more accurately, and the determination of the intensity of the whole ambient light by one pixel is avoided. Moreover, the light intensity measured by each pixel can be adjusted in real time along with the change of the light intensity of the external environment, so that the timeliness and the accuracy of the laser radar for sensing the ambient light are improved. In addition, different ambient light intensity levels are set, so that the ambient light intensity 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 (20)
1. A method of ambient light sensing for a lidar system, the method comprising:
emitting laser pulses to a detection area;
detecting the number of photoexcitation signals generated by each pixel unit of the photodetector during a predetermined period of time for emitting laser pulses;
the ambient light intensity of each pixel cell is determined from the number of detected optical excitation signals.
2. The ambient light sensing method according to claim 1, wherein the pixel unit is a single pixel on the photodetector.
3. The ambient light sensing method according to claim 1, wherein the pixel unit comprises two or more pixels of a photodetector.
4. A method of ambient light sensing 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
and comparing the total quantity of the light excitation signals with a light intensity threshold table to determine the level of the ambient light intensity, wherein the light intensity threshold table comprises a plurality of light intensity thresholds, and each light intensity threshold has a preset quantity of the light excitation signals and represents the corresponding level of the ambient light intensity.
5. The ambient light sensing method according to claim 4, wherein the obtaining of the total amount of the light excitation signals of the predetermined pixel units 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 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.
6. A method as claimed in claim 5, wherein there is a sequence time interval between two consecutive time sequences.
7. The ambient light sensing method according to claim 5, wherein the predetermined pixel unit is a single pixel unit of a photodetector.
8. The ambient light sensing method according to claim 5, wherein the predetermined pixel unit is two or more pixel units of a photodetector.
9. The ambient light sensing method according to claim 4, wherein the photodetector is a single photon avalanche diode chip.
10. A method of ambient light sensing for a lidar system, 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 a detection area by a laser; and
and comparing the total quantity of the light excitation signals with a light intensity threshold table to determine the ambient light intensity level of each pixel unit, wherein the light intensity threshold table comprises a plurality of light intensity thresholds, and each light intensity threshold has a preset quantity of the light excitation signals and represents the corresponding ambient light intensity level.
11. The ambient light sensing method according to claim 10, wherein the obtaining of the total quantity of the light excitation signal for each 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.
12. A method as claimed in claim 11, wherein there is a sequence time interval between two consecutive time sequences.
13. The ambient light sensing method of claim 10, wherein the photodetector is a single photon avalanche diode chip.
14. The ambient light sensing method according to claim 10, wherein the pixel unit is a single pixel of the photodetector.
15. The ambient light sensing method according to claim 10, wherein the pixel unit is two or more pixels of the photodetector.
16. 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 arranged to receive the total amount of light excitation signals and to compare with a light intensity threshold table to determine an ambient light intensity level, wherein the light intensity threshold table comprises a plurality of threshold values, each threshold value having a predetermined number of light excitation signals and being indicative of a corresponding ambient light intensity level.
17. The lidar system of claim 16, wherein the collector is further configured 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.
18. The lidar system of claim 16, wherein the pixel element of the photodetector is a single pixel of the photodetector.
19. The lidar system of claim 16, wherein the pixel unit of the photodetector is two or more pixels of the photodetector.
20. 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 1-15.
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