A laser ranging device and a laser ranging method

Abstract

The present application provides a laser ranging device and a laser ranging method. The device includes: a laser; a transmitting optical component, a receiving optical component, which is arranged on the echo path of the laser reflected by the target, a first photodetector, a second photodetector and a control module. The control module is electrically connected to the laser, the first photodetector and the second photodetector respectively. The control module is configured to trigger the laser and obtain the distance of the target based on a first electrical signal output by the first photodetector and a second electrical signal output by the second photodetector. Compared with the prior art, the time of laser output can be accurately determined by the seed light identical to the laser at the same moment, thereby making the ranging accuracy higher.

Description

Technical Field

[0001] This application relates to the technical field of lidar, and more particularly, to a laser ranging device and a laser ranging method. Background Art

[0002] A lidar is a radar system that detects the position, speed, and other characteristic quantities of a target by emitting a laser beam. Its working principle is to emit a detection signal (laser beam) to the target, and then compare the received signal (target echo) reflected from the target with the transmitted signal. After appropriate processing, the distance to the target can be obtained. However, since the time information of the transmitted signal cannot be accurately determined, the measured distance is not accurate enough. Summary of the Invention

[0003] The purpose of the embodiments of this application is to provide a laser ranging device and a laser ranging method to improve the problem of "the measured distance is not accurate enough because the time information of the transmitted signal cannot be accurately determined".

[0004] The present invention is implemented as follows:

[0005] In a first aspect, the embodiments of this application provide a laser ranging device, including: a laser; for emitting laser and transmitting seed light identical to the laser at the same time when the laser is emitted; a transmitting optical component disposed in the light emitting direction of the laser; the transmitting optical component is used to adjust the direction of the laser; a receiving optical component disposed on the echo path of the laser reflected by the target; a first photodetector connected to the laser, for receiving the seed light and outputting a first electrical signal based on the seed light; a second photodetector disposed on the light condensing path of the receiving optical component, the second photodetector is used to receive the echo aggregated by the receiving optical component and output a second electrical signal based on the echo; and a control module electrically connected to the laser, the first photodetector, and the second photodetector respectively, the control module is used to trigger the laser and obtain the distance of the target based on the first electrical signal and the second electrical signal.

[0006] In the embodiments of this application, when the laser emits laser to the target, it will simultaneously transmit seed light identical to the laser emitted by the laser to the first photodetector. The first photodetector converts the optical signal of the seed light into a first electrical signal and outputs it to the control module, and the second photodetector converts the optical signal of the echo returned by the target received into a second electrical signal and outputs it to the control module. Furthermore, the control module can obtain the accurate distance of the target based on the first electrical signal and the second electrical signal. Compared with the prior art, the time of laser output can be accurately determined by the seed light identical to the laser at the same moment, and thus the ranging accuracy is higher.

[0007] Combined with the technical solution provided in the first aspect above, in some possible implementation manners, the control module includes: a main controller and an FPGA chip; the main controller is electrically connected to the FPGA chip; the main controller is electrically connected to the laser, and the main controller is used to trigger the laser; the FPGA chip is respectively electrically connected to the first photodetector and the second photodetector, and the FPGA chip is used to process the first electrical signal in parallel, process the second electrical signal in parallel, and obtain the distance of the target object based on the first electrical signal and the second electrical signal.

[0008] In the embodiment of the present application, the FPGA chip can process the first electrical signal output by the first photodetector in parallel, process the second electrical signal output by the second photodetector in parallel, and obtain the distance of the target object based on the first electrical signal and the second electrical signal. By means of the parallel processing method of data, the processing time can be reduced.

[0009] Combined with the technical solution provided in the first aspect above, in some possible implementation manners, the transmitting optical assembly includes: a first reflector, the angle of the first reflector is adjustable, and the first reflector is arranged in the light-emitting direction of the laser.

[0010] In the embodiment of the present application, the light-emitting direction of the laser can be flexibly adjusted by the first reflector, and the flexibility of the laser ranging device for ranging can be improved.

[0011] Combined with the technical solution provided in the first aspect above, in some possible implementation manners, the laser ranging device further includes a servo motor, the servo motor is electrically connected to the control module, the servo motor is connected to the first reflector, and the servo motor is used to receive the rotation instruction sent by the control module, and then control the rotation of the first reflector.

[0012] In the embodiment of the present application, by providing a servo motor connected to the first reflector, it is convenient to realize the automatic adjustment of the angle of the first reflector.

[0013] Combined with the technical solution provided in the first aspect above, in some possible implementation manners, the laser ranging device includes a second reflector, the second reflector is arranged between the laser and the first reflector, and a through hole is provided at the center of the second reflector. The laser emitted by the laser enters the reflector through the through hole and then enters the target object; the echo reflected by the target object enters the receiving optical assembly through the first reflector and the second reflector.

[0014] In the embodiment of the present application, by providing the second reflector, the beam range of the received echo can be increased.

[0015] Combined with the technical solution provided in the first aspect above, in some possible implementation manners, the laser is a pulsed laser.

[0016] Combined with the technical solution provided in the first aspect above, in some possible implementation manners, the control module is further configured to trigger the laser to emit waveforms with different pulse widths within each preset time interval.

[0017] In the embodiment of the present application, continuous pulsed trigger measurement can be achieved by triggering the pulsed laser to emit waveforms with different pulse widths within each preset time interval, without waiting until the echo signal of the previous laser returning from the target is received and then emitting the next laser beam.

[0018] In a second aspect, an embodiment of the present application provides a laser ranging method, which is applied to a control module in the laser ranging device provided in the first aspect. The laser is a pulsed laser. The method includes: receiving a first electrical signal output by the first photodetector and receiving a second electrical signal output by the second photodetector; performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal; obtaining the center position of the fitted seed light waveform and the center position of the fitted echo waveform; and obtaining the distance of the target object based on the center position of the fitted seed light waveform and the center position of the fitted echo waveform.

[0019] In the embodiment of the present application, since there are errors in the waveform during the propagation process, the Gaussian waveform fitting algorithm is used to correct the seed light waveform and the echo waveform, so that the distance value of the target object obtained from the seed light waveform and the echo waveform is more accurate.

[0020] Combined with the technical solution provided in the second aspect above, in some possible implementation manners, receiving the first electrical signal output by the first photodetector and receiving the second electrical signal output by the second photodetector includes: receiving a plurality of first electrical signals output by the first photodetector and receiving a plurality of second electrical signals output by the second photodetector; correspondingly, performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal includes: obtaining a target seed light waveform and a target echo waveform with the same waveform in the seed light waveform corresponding to the first electrical signal and the echo waveform corresponding to the second electrical signal; performing Gaussian fitting on the target seed light waveform and the target echo waveform; correspondingly, based on the central position of the fitted seed light waveform and the central position of the fitted echo waveform, obtaining the distance of the target object includes: based on the central position of the fitted target seed light waveform and the central position of the fitted target echo waveform, obtaining the distance of the target object.

[0021] The embodiment of the present application provides a ranging method for continuous multi-pulses. In this method, the control module triggers the laser to emit waveforms with different pulse widths within a preset time interval, and then processes the waveforms with the same pulse width. That is, each seed light and its corresponding echo signal can be distinguished by their pulse widths. Through the above method, continuous pulse trigger measurement is achieved, without waiting until the echo signal of the previous laser beam returning from the target object is received before emitting the next laser beam.

[0022] Combined with the technical solution provided in the second aspect above, in some possible implementation manners, before performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal, the method further includes: obtaining the maximum value m of the waveform in the first electrical signal and the maximum value n of the waveform in the second electrical signal; filtering out the waveforms in the first electrical signal with peaks less than m / 2 to obtain the seed light waveform, and filtering out the waveforms in the second electrical signal with peaks less than n / 2 to obtain the echo waveform.

[0023] The filtering method provided in the present application using the half-wave height as the threshold has better flexibility and accuracy compared with the fixed threshold filtering method in the prior art. Description of the Drawings

[0024] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a block diagram of a laser ranging device provided by an embodiment of the present application.

[0026] Figure 2 It is a schematic structural diagram of a laser ranging device provided by an embodiment of the present application.

[0027] Figure 3 It is a schematic structural diagram of another laser ranging device provided by an embodiment of the present application.

[0028] Figure 4 It is a block diagram of another laser ranging device provided by an embodiment of the present application.

[0029] Figure 5 It is a waveform diagram including 4 pulse widths provided by an embodiment of the present application.

[0030] Figure 6 It is a timing diagram for parallel processing of data provided by an embodiment of the present application.

[0031] Figure 7 It is a step flowchart of a laser ranging method provided by an embodiment of the present application.

[0032] Icon: 100 - Laser ranging device; 10 - Laser; 20 - Transmitting optical component; 21 - First reflector; 22 - Optical device; 30 - Receiving optical component; 40 - First photodetector; 50 - Second photodetector; 60 - Control module; 61 - Main controller; 62 - FPGA chip; 70 - Servo motor; 80 - Second reflector; 91 - Operational amplifier circuit; 92 - AD conversion circuit. Specific embodiments

[0033] The following will describe the technical solutions in the embodiments of the present application in combination with the drawings in the embodiments of the present application.

[0034] Please refer to Figure 1 , an embodiment of the present application provides a laser ranging device 100, including: a laser 10, a transmitting optical component 20, a receiving optical component 30, a first photodetector 40, a second photodetector 50, and a control module 60.

[0035] Among them, the laser 10 is used to emit the laser for scanning towards the target. The emission optical component 20 is arranged in the light-emitting direction of the laser emitted by the laser 10, and the emission optical component 20 is used to adjust the direction of the laser. The reception optical component 30 is arranged on the echo path of the laser reflected by the target. The first photodetector 40 is electrically connected to the laser 10 and the control module 60 respectively. In the embodiment of the present application, when the laser 10 emits the laser beam for scanning towards the target, the seed light identical to the laser emitted by the laser 10 will be transmitted to the first photodetector 40 at the same time. Among them, the fact that the seed light is identical to the laser emitted by the laser 10 includes that their waveforms, pulse widths, and frequencies are all the same. Among them, the first photodetector 40 and the laser 10 are connected by an optical fiber. The first photodetector 40 is used to receive the seed light transmitted by the laser 10 and output a first electrical signal to the control module 60 based on the seed light. That is, the first photodetector 40 is used to convert the optical signal of the received seed light into an electrical signal for output. The second photodetector 50 is arranged on the light-gathering path of the reception optical component 30, and the second photodetector 50 is also electrically connected to the control module 60. The second photodetector 50 is used to receive the echo gathered by the reception optical component 30 and output a second electrical signal to the control module 60 based on the echo. That is, the second photodetector 50 is used to convert the optical signal of the received echo into an electrical signal for output. The control module 60 is used to trigger the laser 10 (such as triggering the opening and closing of the laser 10, and the output power of the laser 10), and obtain the distance of the target based on the first electrical signal output by the first photodetector 40 and the second electrical signal output by the second photodetector 50.

[0036] In the embodiment of the present application, when the laser 10 emits laser towards the target, the seed light identical to the laser emitted by the laser 10 will be transmitted to the first photodetector 40 at the same time. The first photodetector 40 converts the optical signal of the seed light into a first electrical signal and outputs it to the control module 60, and the second photodetector 50 converts the optical signal of the received echo returned by the target into a second electrical signal and outputs it to the control module 60. Furthermore, the control module 60 can obtain the accurate distance of the target based on the first electrical signal and the second electrical signal. Compared with the prior art, the time of laser output can be accurately determined through the seed light identical to the laser at the same moment, and thus the ranging accuracy is higher.

[0037] Please refer to Figure 2 , optionally, the emission optical component 20 includes a first mirror 21. The angle of the first mirror 21 is adjustable, and the first mirror 21 is arranged in the light-emitting direction of the laser. The light-emitting direction of the laser can be flexibly adjusted through the first mirror 21, and the flexibility of the laser ranging device 100 for ranging can be improved.

[0038] To facilitate the adjustment of the angle of the first reflector 21, optionally, the laser ranging device 100 further includes a servo motor 70. Among them, the servo motor 70 is electrically connected to the control module 60, and the servo motor 70 is connected to the first reflector 21. The servo motor 70 is used to receive the rotation instruction sent by the control module 60, and then control the rotation of the first reflector 21. For example, controlling the first reflector 21 to rotate 360 degrees.

[0039] Of course, in other embodiments, the angle of the first reflector 21 can also be adjusted manually, and this application does not make any limitations in this regard.

[0040] Optionally, in order to increase the beam range of the received echo, the laser ranging device 100 includes a second reflector 80. The second reflector 80 is disposed between the laser 10 and the first reflector 21, and a through hole is provided at the center of the second reflector 80. The laser emitted by the laser 10 enters the first reflector 21 through the through hole, and then enters the target object from the first reflector 21; the echo reflected from the target object enters the receiving optical component 30 through the first reflector 21 and the second reflector 80. As Figure 2 can be seen, the receiving optical component 30 can receive a large-area echo beam reflected by the second reflector 80. If the second reflector 80 is not provided, then at this time the receiving optical component 30 can only be disposed on one side of the laser, which will inevitably result in a smaller beam range of the received echo. Therefore, by adopting the structure provided by the embodiments of this application, that is, by providing the second reflector 80 between the laser 10 and the first reflector 21, the beam range of the received echo can be increased.

[0041] Optionally, the above-mentioned transmitting optical component 20 further includes optical devices 22 such as a lens barrel and a grating. The above-mentioned optical devices 22 are connected to the laser 10. Correspondingly, as an implementation manner, the second reflector 80 can be disposed between the optical devices 22 and the first reflector 21 (as Figure 2 shown), as another implementation manner, the second reflector 80 can also be disposed outside the optical devices 22, that is, the optical devices 22 pass through the through hole in the second reflector 80 (as Figure 3 shown). The specific installation position of the second reflector 80 is not limited in this application.

[0042] Optionally, the above-mentioned receiving optical component 30 can be a focusing lens, an imaging lens, etc., and this application does not make any limitations either.

[0043] Optionally, the above-mentioned laser 10 is a pulsed laser. Of course, in other embodiments, the laser can also be a solid laser, a semiconductor laser, etc., and this application does not make any limitations.

[0044] Please refer to Figure 4, in the embodiment of the present application, the control module 60 includes: a main controller 61 and an FPGA (Field Programmable Gate Array) chip 62. The main controller 61 is electrically connected to the FPGA chip 62.

[0045] Among them, the main controller 61 is electrically connected to the laser 10, and the main controller 61 is used to trigger the laser 10 (such as triggering the turn-on and turn-off of the laser 10, and the output power of the laser 10).

[0046] Optionally, when the laser 10 is a pulsed laser, the main controller 61 is further used to trigger the pulsed laser to emit waveforms with different pulse widths within each preset time interval.

[0047] It should be explained that since the conventional lidar ranging is that the laser emits a laser waveform with an equal pulse width, and at the same time the acquisition end also receives a signal that is also a pulse, the next laser must wait until the echo signal returned from the previous laser from the target is received before emitting the next laser, otherwise it is impossible to distinguish which laser number the echo is from. In specific application scenarios, such as in catenary detection, it is generally considered that one scan of the laser pulse is one line; the more valid points within one line, the higher the recognition accuracy of the catenary to be detected.

[0048] Assume that the effective ranging range is 15 meters; then the minimum time interval t of laser ranging = 2 * 15 / c = 100 nanoseconds; where c is the speed of light in air. That is, the maximum measurement frequency is P (equal to 10M); at the same time, assume that the pulse scanning frequency of the laser is N circles / second; then the effective number of pulses in one line is M (equal to P / N). When the scanner rotation speed R is fixed, the higher the laser repetition frequency, the more effective ranging pulse data in one line. Therefore, by increasing the trigger frequency of the laser, the effective pulse data in one line can be increased; in this way, we can detect a longer railway mileage within a limited time, greatly improving the detection efficiency. Therefore, in order to improve the measurement frequency, different pulse-width laser waveforms are emitted, and each seed light and its corresponding echo signal can be distinguished by its pulse width (as Figure 5 shown, Figure 5 shows waveforms with 4 different pulse widths). Of course, in other embodiments, the preset time interval can also be 150 nanoseconds, 200 nanoseconds, etc., which is not limited in this application.

[0049] In the embodiment of the present application, continuous pulse trigger measurement can be achieved by triggering the pulsed laser to emit waveforms with different pulse widths within each preset time interval, without waiting until the echo signal returned from the previous laser from the target is received before emitting the next laser beam.

[0050] The FPGA chip 62 is electrically connected to the first photodetector 40 and the second photodetector 50, respectively. The FPGA chip 62 is configured to process the first electrical signal output by the first photodetector 40 and the second electrical signal output by the second photodetector 50 in parallel. Specifically, the FPGA chip 62 is configured to process the waveform data in the first electrical signal output by the first photodetector 40 and the waveform data in the second electrical signal output by the second photodetector 50 in parallel. The FPGA chip 62 is also configured to obtain the distance to the target object based on the first electrical signal and the second electrical signal.

[0051] Typically, waveform data rates can reach 5 GHz × 10 bits. Therefore, subsequent waveform data processing using FPGA chip 62 must also meet a 5 GHz × 10 bit rate to meet real-time requirements. To ensure the stability of FPGA program execution, a 208.3 MHz clock is selected as the data processing clock. Therefore, 24 data points must be processed simultaneously during each clock cycle, converting 5 GHz × 10 bits to 208.3 MHz × 240 bits. If all 24 data points are evaluated simultaneously, since waveform recognition requires combining a segment of data for evaluation, rather than independently evaluating each individual data point, this will result in coupling between the evaluation criteria for the 24 data points. This will result in excessively long internal FPGA wiring paths after synthesis, making it impossible to complete within a single cycle and failing to meet timing requirements. To address this issue, the FPGA's parallel nature can be exploited to employ four parallel modules for data processing, meaning each module simultaneously processes six waveform data points during a single clock cycle. As an implementation method, these four parallel modules may not process 24 data of the same clock cycle, but may first store a period of 5GHz data in the memory, and then a single module may sequentially retrieve 6 data at a clock frequency of 208.3MHz and process them, and then switch to accessing another memory at the next laser trigger signal, thereby realizing real-time waveform processing of 5GHz data, such as Figure 6 As shown, when module 1 processes data stream 1, module 2 then processes data stream 2, module 3 then processes data stream 3, module 4 then processes data stream 4, and then the cycle repeats. Module 1 then receives and processes data stream 5, thus implementing parallel processing on the FPGA chip. Of course, in other embodiments, the clock frequency can also be 200 MHz, and this application does not limit this.

[0052] In the embodiment of the present application, the FPGA chip 62 can process the first electrical signal output by the first photodetector 40 and the second electrical signal output by the second photodetector 50 in parallel, and obtain the distance of the target object based on the first and second electrical signals. By processing data in parallel, processing time can be reduced.

[0053] It should be noted that the specific ranging algorithm of the FPGA chip 62 will be described in the subsequent method embodiments and will not be elaborated here too much.

[0054] Please continue to refer to Figure 4 , optionally, the laser ranging device further includes an operational amplifier circuit 91. The operational amplifier circuit 91 is electrically connected to the first photodetector 40, the second photodetector 50, and the control module 60 respectively. Among them, the operational amplifier circuit 91 is used to process the weak electrical signals transmitted by the first photodetector 40 and the second photodetector 50, including transimpedance amplification and automatic gain amplification. It should be noted that since transimpedance amplification and automatic gain amplification are well-known circuit structures in the art, the present application will not elaborate too much on them.

[0055] When the above control module 60 includes a main controller 61 and an FPGA chip 62, the operational amplifier circuit 91 is electrically connected to the FPGA chip 62.

[0056] Optionally, the laser ranging device 100 further includes an AD conversion circuit 92. The AD conversion circuit 92 is electrically connected to the first photodetector 40, the second photodetector 50, and the control module 60 respectively. Among them, the AD conversion circuit 92 is used to convert the analog signals output by the first photodetector 40 into digital signals, and convert the analog signals output by the second photodetector 50 into digital signals, and then output them to the control module 60. It should be noted that since the AD conversion circuit 92 is a well-known circuit structure in the art, the present application will not elaborate too much on it.

[0057] When the above control module 60 includes a main controller 61 and an FPGA chip 62, and the laser ranging device 100 includes an operational amplifier circuit 91, the AD conversion circuit 92 is electrically connected to the operational amplifier circuit 91 and the FPGA chip 62 respectively.

[0058] Optionally, the laser ranging device 100 further includes a display module. The display module is connected to the control module, and the display module can be electrically connected to the control module 60. When the laser ranging device 100 further includes a communication module, the control module 60 can also establish a communication connection with the display module. The display module is used to display the distance of the target object obtained by the control module.

[0059] The above display module can be a display, a tablet, or a mobile phone, that is, the display module can also be any terminal device including a display interface.

[0060] Based on the same concept, an embodiment of the present application further provides a catenary detection device, which includes a vehicle body and a laser ranging device provided on the vehicle body as described in the above embodiment. When the vehicle body moves on the railway, the laser ranging device provided on the vehicle body can measure the distance to the catenary. The laser ranging device provided by the embodiment of the present application can improve the accuracy of the detected distance.

[0061] It can be understood that the laser ranging device provided by the embodiment of the present application can be applied not only to the field of catenary detection, but also to the fields of aerospace, such as being provided on an unmanned aerial vehicle for monitoring the flight environment.

[0062] Please refer to Figure 7 , based on the same concept, an embodiment of the present application further provides a laser ranging method, which is applied to the control module in the laser ranging device as described in the above embodiment. Among them, the laser in the laser ranging device is a pulsed laser, and this method includes: step S101 - step S103.

[0063] Step S101: Receive the first electrical signal output by the first photodetector and receive the second electrical signal output by the second photodetector.

[0064] Step S102: Perform Gaussian fitting on the seed light waveform corresponding to the first electrical signal and perform Gaussian fitting on the echo waveform corresponding to the second electrical signal; obtain the center position of the fitted seed light waveform and the center position of the fitted echo waveform.

[0065] The specific process of the above Gaussian fitting will be described below.

[0066] The Gaussian waveform can be expressed by the following formula (1):

[0067]

[0068] Among them, y is the amplitude, x is the abscissa value, S and A are Gaussian waveform coefficients, and μ is the abscissa of the center point.

[0069] Take the logarithm of both sides of the above formula to get:

[0070]

[0071] Let In y = z; Get:

[0072] z = b0 + b1x + b2x 2 (3)

[0073]

[0074] Write the n waveform data in matrix form. It should be noted that in the subsequent calculation process, the processing of the seed light waveform and the echo waveform is carried out separately, and the processing processes are the same. Therefore, the n waveforms in this step can refer to the seed light waveform or the echo waveform. The matrix form is as follows:

[0075]

[0076] Denoted as:

[0077] Z = XB (6)

[0078] Using the least square principle, we can get:

[0079] (X T XB) = X T Z (7)

[0080] B = (X T X) -1 X T Z (8)

[0081] Expand equation (7) into matrix form as:

[0082]

[0083] Since X T X and X T Z are all known numbers, if we directly use the Gaussian elimination method to solve the equation at this time, it will introduce multiple division operations. And one division operation will take several to more than a dozen clock cycles, and integer division will lose precision. Therefore, optimization is needed. Note that x is the continuous abscissa of the waveform. After recording the coordinate of the initial x1, we can let x i = i, that is, equation (9) is transformed into:

[0084]

[0085] Using the summation formula:

[0086]

[0087] Substitute the summation formula (11) into (10) to get:

[0088]

[0089] After simplifying formula (12) using the Gaussian elimination method, we get:

[0090]

[0091] The center point μ1 of the seed light waveform and the center point μ2 of the echo waveform can be obtained through the above formula (13). Since the starting point x1 of the seed light waveform and the starting point x2 of the echo waveform are known, therefore, the accurate center position of the seed light waveform can be obtained based on the center point μ1 of the seed light waveform and the starting point x1 of the seed light waveform, and the accurate center position of the echo waveform can be obtained based on the center point μ2 of the echo waveform and the starting point x2 of the echo waveform.

[0092] Step S103: Based on the center position of the fitted seed light waveform and the center position of the fitted echo waveform, obtain the distance of the target object.

[0093] After obtaining the center point μ1 of the seed light waveform and the center point μ2 of the echo waveform as described above, the accurate center position of the seed light waveform is obtained based on the center point μ1 of the seed light waveform and the starting point x1 of the seed light waveform, and the accurate center position of the echo waveform is obtained based on the center point μ2 of the echo waveform and the starting point x2 of the echo waveform, and then the distance value d of the target object is obtained:

[0094]

[0095] The above c is the speed of light propagating in air.

[0096] In the embodiment of the present application, since there are errors in the waveform during the propagation process, therefore, the Gaussian waveform fitting algorithm is used to correct the seed light waveform and the echo waveform as described above, so that the distance value of the target object obtained through the seed light waveform and the echo waveform is more accurate.

[0097] Optionally, when the control module triggers the laser to emit waveforms with different pulse widths within a preset time interval, receiving the first electrical signal output by the first photodetector and receiving the second electrical signal output by the second photodetector in the above step S101 further includes:

[0098] Receiving a plurality of first electrical signals output by the first photodetector and receiving a plurality of second electrical signals output by the second photodetector.

[0099] Correspondingly, step S102, performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal, includes: obtaining a target seed light waveform and a target echo waveform with the same waveform in the seed light waveform corresponding to the first electrical signal and the echo waveform corresponding to the second electrical signal; performing Gaussian fitting on the target seed light waveform and the target echo waveform.

[0100] Correspondingly, step S103 of obtaining the distance of the target object based on the center position of the fitted seed light waveform and the center position of the fitted echo waveform includes: obtaining the distance of the target object based on the center position of the fitted target seed light waveform and the center position of the fitted target echo waveform.

[0101] It can be understood that the embodiment of the present application provides a ranging method for continuous multi-pulses. In this method, the control module triggers the laser to emit waveforms with different pulse widths within a preset time interval, and then processes the waveforms with the same pulse width. That is, each seed light and its corresponding echo signal can be distinguished by their pulse widths. Through the above method, continuous pulse trigger measurement is realized, and there is no need to wait until the echo signal of the previous laser returning from the target object is received before emitting the next laser beam.

[0102] Optionally, before performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and Gaussian fitting on the echo waveform corresponding to the second electrical signal, the method further includes: obtaining the maximum value m of the waveforms in the first electrical signal and the maximum value n of the waveforms in the second electrical signal; filtering out the waveforms in the first electrical signal with peaks less than m / 2 to obtain the seed light waveform, and filtering out the waveforms in the second electrical signal with peaks less than n / 2 to obtain the echo waveform.

[0103] That is, the present application adopts a threshold filtering method, which uses half of the maximum value of the obtained waveform as the threshold for filtering, thereby removing the interference waveforms smaller than the threshold. In the prior art, the fixed threshold method has poor flexibility. If the threshold is too low, it may cause the deformation of the bottom end of the waveform and the interception of data with low signal-to-noise ratio, affecting the fitting accuracy and ranging accuracy. If the threshold is too high, small-signal echoes will be ignored, affecting the ranging range. Therefore, the filtering method provided by the present application using the half-wave height as the threshold has better flexibility and accuracy.

[0104] Of course, in other embodiments, filtering can also be performed according to dimensions such as the width and intensity of the waveform, and the present application does not limit this.

[0105] In summary, the laser ranging method provided by the embodiment of the present application corrects the seed light waveform and the echo waveform through the Gaussian waveform fitting algorithm, thereby making the distance value of the target object obtained from the seed light waveform and the echo waveform more accurate. In addition, this method can also perform continuous pulse trigger measurement, and there is no need to wait until the echo signal of the previous laser returning from the target object is received before emitting the next laser beam. Moreover, the embodiment of the present application also performs filtering with the half-wave height as the threshold, providing overall flexibility and filtering accuracy.

[0106] In this document, relational terms such as first and second are used solely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0107] The above description is only for the embodiments of this application and is not intended to limit the protection scope of this application. For those skilled in the art, this application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A laser ranging device, characterized in that, Comprising: A laser; for emitting laser light and transmitting seed light identical to the laser light while emitting the laser light; An emission optical component, arranged in the light-emitting direction of the laser light; the emission optical component is used for adjusting the direction of the laser light; A reception optical component, arranged on the echo path of the laser light reflected by the target; A first photodetector, connected to the laser, for receiving the seed light and outputting a first electrical signal based on the seed light; A second photodetector, arranged on the light-gathering path of the reception optical component, the second photodetector is used for receiving the echo gathered by the reception optical component and outputting a second electrical signal based on the echo; And A control module, electrically connected to the laser, the first photodetector and the second photodetector respectively, the control module is used for triggering the laser and obtaining the distance of the target based on the first electrical signal and the second electrical signal; Wherein, when the control module obtains the distance of the target based on the first electrical signal and the second electrical signal, it is specifically used for: Performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal; obtaining the center position of the fitted seed light waveform and the center position of the fitted echo waveform; Obtaining the distance of the target based on the center position and starting point of the fitted seed light waveform and the center position and starting point of the fitted echo waveform.

2. The laser ranging device according to claim 1, characterized in that, The control module includes: a main controller and an FPGA chip; the main controller is electrically connected to the FPGA chip; The main controller is electrically connected to the laser, and the main controller is used for triggering the laser; The FPGA chip is electrically connected to the first photodetector and the second photodetector respectively, and the FPGA chip is used for processing the first electrical signal in parallel, processing the second electrical signal in parallel and obtaining the distance of the target based on the first electrical signal and the second electrical signal.

3. The laser distance measuring device according to claim 1, characterized in that, The emission optical component includes: a first reflector, the angle of the first reflector is adjustable, and the first reflector is arranged in the light-emitting direction of the laser light.

4. The laser distance measuring device according to claim 3, wherein The laser distance measuring device further includes a servo motor, the servo motor is electrically connected to the control module, the servo motor is connected to the first reflector, and the servo motor is used for receiving the rotation instruction sent by the control module and then controlling the rotation of the first reflector.

5. The laser ranging device according to claim 3, characterized in that, The laser distance measuring device includes a second reflector, the second reflector is arranged between the laser and the first reflector, and a through hole is provided at the center of the second reflector, the laser light emitted by the laser enters the reflector through the through hole and then enters the target; the echo reflected by the target enters the reception optical component through the first reflector and the second reflector.

6. The laser distance measuring device according to claim 1, characterized in that The laser is a pulsed laser.

7. The laser ranging device according to claim 6, characterized in that, The control module is further used for triggering the laser to emit waveforms with different pulse widths at each preset time interval.

8. A laser ranging method, characterized in that, A control module applied to the laser ranging device as described in claim 1, wherein the laser is a pulsed laser, and the method includes: Receiving a first electrical signal output by the first photodetector and receiving a second electrical signal output by the second photodetector; Performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal; obtaining the center position of the fitted seed light waveform and the center position of the fitted echo waveform; Based on the center position and starting point of the fitted seed light waveform and the center position and starting point of the fitted echo waveform, obtaining the distance to the target object.

9. The laser ranging method according to claim 8, characterized in that The receiving the first electrical signal output by the first photodetector and receiving the second electrical signal output by the second photodetector includes: Receiving a plurality of first electrical signals output by the first photodetector and receiving a plurality of second electrical signals output by the second photodetector; Correspondingly, performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal includes: Obtaining a target seed light waveform and a target echo waveform with the same waveform in the seed light waveform corresponding to the first electrical signal and the echo waveform corresponding to the second electrical signal; Performing Gaussian fitting on the target seed light waveform and the target echo waveform; Correspondingly, based on the center position and starting point of the fitted seed light waveform and the center position and starting point of the fitted echo waveform, obtaining the distance to the target object includes: Based on the center position and starting point of the fitted target seed light waveform and the center position and starting point of the fitted target echo waveform, obtaining the distance to the target object.

10. The laser ranging method according to claim 8, wherein Before performing Gaussian fitting on the seed light waveform corresponding to the first electrical signal and performing Gaussian fitting on the echo waveform corresponding to the second electrical signal, the method further includes: Obtaining the maximum value m of the waveform in the first electrical signal and the maximum value n of the waveform in the second electrical signal; Filtering out the waveforms in the first electrical signal with peaks less than m / 2 to obtain the seed light waveform, and filtering out the waveforms in the second electrical signal with peaks less than n / 2 to obtain the echo waveform.

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