A laser ranging method and system

Abstract

The application discloses a laser ranging method and system, wherein in the case that a linear frequency modulation laser signal is not emitted, an environmental noise signal is received, ADC sampling is performed to obtain a first signal; an initialized comparator threshold value is determined according to the first signal; the linear frequency modulation laser signal is emitted to a to-be-measured object, and a returned echo signal is received; the echo signal is converted and processed based on the comparator threshold value to obtain a corresponding square wave signal; the square wave signal is filtered to obtain a target signal; peak value detection is performed on the target signal, and a first signal point, a second signal point and a third signal point are determined from the target signal; signal-to-noise ratio data of the target signal is calculated; and if the signal-to-noise ratio data is greater than or equal to a preset threshold value, the measurement distance corresponding to the to-be-measured object is determined according to the first signal point, the second signal point and the third signal point. The method can improve the efficiency of the ranging application and reduce the application cost. The application can be widely applied in the ranging technical field.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of distance measurement technology, and in particular to a laser distance measurement method and system. BACKGROUND

[0002] Laser distance measurement technology is a technology that uses laser to measure distance. The principle is to use the high monochromaticity, high brightness and high modulation performance of laser to emit laser signals to the object to be measured, and calculate the distance between the object to be measured and the laser emitter by measuring the time required for the laser signal to be reflected back. Single-frequency phase distance measurement is one of the commonly used technologies, which calculates the distance by measuring the phase difference of the laser signal. However, this technology has a phase ambiguity problem, that is, when the distance is too far or too close, the phase difference will exceed the limit range and the distance cannot be measured correctly.

[0003] In related technologies, to solve the above problems, general phase distance measurement will use multiple rulers with different frequencies to emit alternately. However, this method requires a long time for multiple rulers to emit alternately, greatly reducing the measurement frequency. Under the premise of ensuring measurement accuracy, the measurement frequency is often limited to below 10Hz, and the system has weak anti-interference ability. In many current practical applications, distance measurement systems with high distance measurement accuracy and fast measurement speed are required, such as precise positioning and fast measurement in warehouse and conveying systems. The existing distance measurement method often cannot meet the actual demand, or has too high requirements for the laser pulse receiving circuit, and the digital signal processing is complex and expensive.

[0004] Therefore, the problems of the prior art still need to be solved and optimized. SUMMARY

[0005] The present application aims to at least partly solve one of the technical problems in the related art.

[0006] To this end, one purpose of the embodiments of the present application is to provide a laser distance measurement method and system.

[0007] In order to achieve the above technical purpose, the technical solutions adopted by the embodiments of the present application include:

[0008] On the one hand, the embodiments of the present application provide a laser distance measurement method, which comprises:

[0009] Receiving an ambient noise signal without emitting a linear frequency modulation laser signal;

[0010] Performing ADC sampling on the ambient noise signal to obtain a first signal;

[0011] Determining an initialized comparator threshold value according to the first signal;

[0012] transmitting a linear frequency modulation laser signal to a to-be-measured object, and receiving a returned echo signal;

[0013] performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal;

[0014] performing smoothing filtering processing and matching filtering processing on the square wave signal to obtain a target signal;

[0015] performing peak value detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal, wherein the second signal point is a peak value point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a subsequent signal point of the second signal point;

[0016] calculating signal-to-noise ratio data of the target signal;

[0017] if the signal-to-noise ratio data is greater than or equal to a preset threshold value, determining a measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point, or if the signal-to-noise ratio data is less than the preset threshold value, updating the comparator threshold value, and returning to the step of transmitting a linear frequency modulation laser signal to a to-be-measured object, and receiving a returned echo signal.

[0018] In addition, the laser ranging method according to the above-mentioned embodiments of the present application can further have the following additional technical features:

[0019] Further, in an embodiment of the present application, before the step of performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal, the method further comprises:

[0020] performing amplification processing on the echo signal.

[0021] Further, in an embodiment of the present application, the linear frequency modulation laser signal is a laser signal in which a high-level signal and a low-level signal are alternated, and the alternating frequency of the high-level signal and the low-level signal in the linear frequency modulation laser signal is first reduced and then increased.

[0022] Further, in an embodiment of the present application, the step of performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal comprises:

[0023] comparing each to-be-converted signal point on the echo signal with the comparator threshold value;

[0024] If the amplitude of the signal point to be converted is less than the comparator threshold, the signal point to be converted is adjusted to a low-level signal point; or, if the amplitude of the signal point to be converted is greater than or equal to the comparator threshold, the signal point to be converted is adjusted to a high-level signal point.

[0025] Furthermore, in one embodiment of this application, determining the measurement distance corresponding to the object to be measured based on the first signal point, the second signal point, and the third signal point includes:

[0026] The measurement distance corresponding to the object to be measured is determined by the following formula:

[0027]

[0028] In the formula, d f The calculated measurement distance is represented by , where 'a' is a constant parameter, 'z1' represents the matching amplitude value corresponding to the first signal point, 'z2' represents the matching amplitude value corresponding to the second signal point, 'z3' represents the matching amplitude value corresponding to the third signal point, 'n1' represents the time point corresponding to the first signal point, 'n2' represents the time point corresponding to the second signal point, and 'n3' represents the time point corresponding to the third signal point.

[0029] Furthermore, in one embodiment of this application, calculating the signal-to-noise ratio data of the target signal includes:

[0030] The signal-to-noise ratio of the target signal is calculated using the following formula:

[0031]

[0032] In the formula, SNR represents the signal-to-noise ratio data, z(n) represents the target signal, max(z(n)) represents the peak value in the target signal, and λ represents the comparator threshold.

[0033] Furthermore, in one embodiment of this application, updating the comparator threshold includes:

[0034] The comparator threshold is updated using the following formula:

[0035]

[0036] In the formula, λ2 represents the updated comparator threshold, z(n) represents the target signal, max(z(n)) represents the peak value in the target signal, and λ1 represents the comparator threshold before the update.

[0037] Further, in one embodiment of this application, determining the initialized comparator threshold based on the first signal includes:

[0038] The noise level of the first signal is calculated by the following formula:

[0039]

[0040] wherein ε represents the noise level, N represents the number of signal points in the first signal, n represents the number of signal points in the first signal, and q(t) represents the first signal;

[0041] According to the noise level, the initialized comparator threshold is determined by the following formula:

[0042] λ0=bε

[0043] wherein λ0 represents the initialized comparator threshold, ε represents the noise level, and b is a constant.

[0044] In another aspect, the embodiments of the present application provide a laser ranging system, which comprises:

[0045] a processing unit, a laser driving unit, a laser emitting unit, a laser receiving unit, and a comparator unit; the processing unit is connected to the laser emitting unit through the laser driving unit, the laser receiving unit is connected to the comparator unit, and the comparator unit is connected to the processing unit;

[0046] The processing unit comprises a smoothing filter, a waveform matching filter, a peak detection module, a signal-to-noise ratio calculation module, a distance calculation module, an ADC sampling module, a comparator threshold calculation module, and a comparator threshold control module.

[0047] The processing unit is configured to drive the laser emitting unit to emit a linear frequency modulation laser signal to an object to be measured through the laser driving unit.

[0048] The laser receiving unit is configured to receive a returned echo signal and an environmental noise signal in the case where no linear frequency modulation laser signal is emitted.

[0049] The comparator unit is configured to perform conversion processing on the echo signal based on a comparator threshold to obtain a corresponding square wave signal.

[0050] The processing unit is further configured to perform smoothing filter processing on the square wave signal through the smoothing filter and perform matching filter processing on the signal after the smoothing filter processing through the waveform matching filter to obtain a target signal.

[0051] The peak detection module is configured to perform peak detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal, wherein the second signal point is a peak point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a next signal point of the second signal point.

[0052] The signal-to-noise ratio calculation module is configured to calculate signal-to-noise ratio data of the target signal.

[0053] The distance calculation module is configured to determine a measurement distance corresponding to the object to be measured according to the first signal point, the second signal point and the third signal point.

[0054] The ADC sampling module is configured to perform ADC sampling on the ambient noise signal to obtain a first signal.

[0055] The comparator threshold calculation module is configured to determine an initialized comparator threshold according to the first signal.

[0056] The comparator threshold control module is configured to adjust the comparator threshold.

[0057] Further, in an embodiment of the present application, the processing unit includes a first processing unit and a second processing unit; the first processing unit adopts a programmable logic array logic chip, and the second processing unit adopts a single-chip microcomputer chip; the first processing unit and the second processing unit are connected in communication through a serial peripheral interface.

[0058] The first processing unit includes the smoothing filter, the waveform matching filter, the peak detection module, the signal-to-noise ratio calculation module and the distance calculation module; and the second processing unit includes the ADC sampling module, the comparator threshold calculation module and the comparator threshold control module.

[0059] On the other hand, an embodiment of the present application provides a laser ranging device, which includes:

[0060] At least one processor;

[0061] At least one memory configured to store at least one program;

[0062] When the at least one program is executed by the at least one processor, the at least one processor is caused to implement the above-described laser ranging method.

[0063] On the other hand, an embodiment of the present application further provides a computer readable storage medium, which stores a processor-executable program, and the above-described processor-executable program, when executed by a processor, is used to implement the above-described laser ranging method.

[0064] The advantages and beneficial effects of the present application will be partially given in the following description, partially will become obvious from the following description, or will be learned by the practice of the present application:

[0065] The method comprises the following steps: receiving an environmental noise signal without emitting a linear frequency modulation laser signal; performing ADC sampling on the environmental noise signal to obtain a first signal; determining an initialized comparator threshold value according to the first signal; emitting a linear frequency modulation laser signal to a to-be-measured object and receiving a returned echo signal; performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal; performing filtering processing on the square wave signal to obtain a target signal; performing peak value detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal; the second signal point is a peak value point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a subsequent signal point of the second signal point; calculating signal-to-noise ratio data of the target signal; if the signal-to-noise ratio data is greater than or equal to a preset threshold value, determining a measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point; or, if the signal-to-noise ratio data is less than the preset threshold value, updating the comparator threshold value, and returning to the step of emitting a linear frequency modulation laser signal to a to-be-measured object and receiving a returned echo signal. The method can obtain a relatively accurate measurement distance result, has relatively high ranging accuracy and relatively fast measurement speed, has relatively low requirements on hardware devices, is beneficial to reducing the implementation cost of laser ranging, and can improve the efficiency of ranging application. BRIEF DESCRIPTION OF DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following introduces the drawings of the related technical solutions in the embodiments of the present application or the prior art. It should be understood that the drawings in the following introduction are only for the convenience of clearly describing part of the embodiments of the present application, and those skilled in the art can obtain other drawings from these drawings without creative labor.

[0067] Figure 1 The flowchart of the first laser ranging method provided in the embodiments of the present application is shown in the figure.

[0068] Figure 2 The structure diagram of the first laser ranging system provided in the embodiments of the present application is shown in the figure.

[0069] Figure 3 The flowchart of the specific implementation of the laser ranging method provided in the embodiments of the present application is shown in the figure.

[0070] Figure 4 A schematic diagram of a chirp laser signal provided for an embodiment of the present application;

[0071] Figure 5 A schematic diagram of an echo signal before processing by a comparator unit provided for an embodiment of the present application;

[0072] Figure 6 A schematic diagram of an echo signal after processing by a comparator unit provided for an embodiment of the present application;

[0073] Figure 7 A structural schematic diagram of a smoothing filter provided for an embodiment of the present application;

[0074] Figure 8 A schematic diagram of an output signal after smoothing filter processing provided for an embodiment of the present application;

[0075] Figure 9 A structural schematic diagram of a waveform matching filter provided for an embodiment of the present application;

[0076] Figure 10 A schematic diagram of a target signal provided for an embodiment of the present application;

[0077] Figure 11 A schematic diagram of a first signal point, a second signal point and a third signal point found in a target signal provided for an embodiment of the present application;

[0078] Figure 12 A flowchart of a second laser ranging method provided for an embodiment of the present application;

[0079] Figure 13 A structural schematic diagram of a second laser ranging system provided for an embodiment of the present application;

[0080] Figure 14 A structural schematic diagram of a third laser ranging system provided for an embodiment of the present application;

[0081] Figure 15 A flowchart of a third laser ranging method provided for an embodiment of the present application;

[0082] Figure 16 A structural schematic diagram of a fourth laser ranging system provided for an embodiment of the present application;

[0083] Figure 17 A structural schematic diagram of a fifth laser ranging system provided for an embodiment of the present application. DETAILED DESCRIPTION

[0084] The application will be further described below in conjunction with the accompanying drawings and specific embodiments. The described embodiments should not be regarded as limiting the application, and all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0085] In the following description, "some embodiments" are related to a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0086] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application belongs. The terms used herein are only for the purpose of describing the embodiments of the application and are not intended to limit the application.

[0087] Laser ranging technology is a technology for measuring distance using laser. The principle is to use the high monochromaticity, high brightness and high modulation performance of laser to emit laser signals to the object to be measured, and to calculate the distance between the object to be measured and the laser emitter by measuring the time required for the laser signal to be reflected back. Single-frequency phase ranging is one of the commonly used technologies, which calculates the distance by measuring the phase difference of the laser signal. However, this technology has the problem of phase ambiguity, that is, when the distance is too far or too close, the phase difference will exceed the limit and the distance cannot be measured correctly.

[0088] In the related art, to solve the above problem, the general phase ranging will use multiple rulers of different frequencies to emit alternately. However, this method requires a long time for multiple rulers to emit alternately, greatly reducing the measurement frequency. Under the premise of ensuring measurement accuracy, the measurement frequency is often limited to below 10 Hz, and the system has weak anti-interference ability. In many current practical applications, ranging systems with high ranging accuracy and fast measurement speed are required, such as precise positioning and fast measurement in warehouse and conveying systems. The existing ranging method often cannot meet the actual demand, or has too high requirements for the laser pulse receiving circuit, and the digital signal processing is complex and expensive.

[0089] Therefore, in the embodiments of the present application, a laser ranging method is provided, which can obtain a more accurate measurement distance result, has high ranging accuracy and fast measurement speed, and has low requirements for hardware devices, which is beneficial to reduce the implementation cost of laser ranging, has a simple processing flow, and can improve the efficiency of ranging application.

[0090] Please refer to Figure 1 , Figure 1 is a flowchart of a laser ranging method provided by the embodiments of the present application, which is described with reference toFigure 1 The laser ranging method provided in the application includes but is not limited to the following steps:

[0091] Step 110, emitting a linear frequency modulation laser signal to the object to be measured, and receiving a returned echo signal;

[0092] In this step, when performing laser ranging, the object to be measured can be recorded as the object to be measured, and the distance between the object to be measured and the laser ranging device is detected, that is, the distance between the object to be measured and the laser ranging device is detected. In the embodiment of the application, the type, size, shape of the object to be measured and the distance between the object to be measured and the laser ranging device are not limited; the laser ranging device can be a separate device or a small integrated component on other devices, and the application does not limit this. When laser ranging is performed on the object to be measured, a linear frequency modulation laser signal can be emitted to the object to be measured, that is, a laser signal with a constantly changing frequency is emitted to the object to be measured. This signal has a wideband property and can have a corresponding effect on the object to be measured, thereby generating an echo signal. The laser ranging device can receive the echo signal and detect the distance of the object to be measured based on the echo signal.

[0093] In the embodiment of the application, the linear frequency modulation laser signal has the advantages of high measurement accuracy, wide ranging range, fast measurement speed and the like, and can be widely applied to industrial, military and environmental monitoring fields.

[0094] Step 120, converting the echo signal based on a comparator threshold value to obtain a corresponding square wave signal;

[0095] It can be understood that in the application of laser ranging, the laser ranging device receives the linear frequency modulation laser signal reflected by the object to be measured through the related unit module. During the transmission process, the signal will be affected by factors such as interference and attenuation, and therefore needs to be processed, such as time domain analysis and frequency domain analysis, to obtain the characteristic parameters of the echo signal, so as to realize the distance measurement of the object to be measured.

[0096] In this step, after obtaining the echo signal, the echo signal can be converted to obtain a corresponding square wave signal. Specifically, in the embodiment of the application, the echo signal can be converted based on a comparator. The comparator is an electronic element that can compare the input signal with a set threshold value. When the amplitude of the input signal exceeds the threshold value, a high level is output, otherwise a low level is output. In the laser ranging technology, each signal point to be converted on the echo signal can be compared with the comparator threshold value. The signal points in the echo signal with an amplitude greater than or equal to the comparator threshold value are adjusted to high level signal points, and the signal points in the echo signal with an amplitude less than the comparator threshold value are adjusted to low level signal points. In this way, the echo signal can be converted into a corresponding square wave signal, so that it can be subjected to subsequent signal processing.

[0097] It should be noted that in some embodiments, the echo signal can also be amplified before being converted. The amplification process increases the amplitude of the echo signal, making it easier to be detected by the comparator and converted into a square wave signal corresponding to it. The amplification process can use electronic components such as amplifiers to amplify the amplitude of the echo signal to an appropriate size. In the embodiments of the present application, the use of amplification can not only improve the detection sensitivity of the signal, but also reduce the noise interference of the signal, thereby improving the signal quality and stability. It should be noted that during the amplification process, excessive amplification should be avoided to cause signal distortion and noise increase. In the embodiments of the present application, the specific parameters of the amplification process are not limited and can be flexibly selected as needed.

[0098] Step 130, performing smoothing filtering and matching filtering on the square wave signal to obtain a target signal;

[0099] In this step, after obtaining the square wave signal, smoothing filtering and matching filtering can be performed on the square wave signal to obtain a target signal. Here, smoothing filtering and matching filtering are different filtering algorithms and are mainly used for signal denoising and information extraction. Specifically, smoothing filtering is a basic filtering algorithm, and its principle is to reduce the influence of noise on the signal by weighted averaging of the signal, thereby achieving signal smoothing. Common smoothing filtering algorithms include moving average filtering and median filtering. Moving average filtering achieves smoothing by calculating the moving average of the signal, which is suitable for processing stationary signals; median filtering replaces the original signal value with the median of the data in the signal window, which is suitable for processing non-stationary signals.

[0100] Matching filtering is a special filtering algorithm, and its principle is to compare the input signal with a predetermined reference signal to obtain the similarity between the two, thereby achieving signal recognition and matching. Matching filtering algorithm has a wide range of applications in signal processing, such as radar signal processing, digital image processing, and speech recognition. The key to matching filtering is to design a good reference signal, and common design methods include correlation function-based design and minimum mean square error-based design. In the embodiments of the present application, the reference signal can be a pre-stored linear frequency modulation laser signal. Through matching filtering, the received signal and noise signal in the echo signal can be distinguished, thereby obtaining the target signal.

[0101] Step 140, performing peak detection on the target signal to determine a first signal point, a second signal point, and a third signal point from the target signal; wherein the second signal point is a peak point in the target signal, the first signal point is a signal point before the second signal point, and the third signal point is a signal point after the second signal point.

[0102] In this step, after obtaining the target signal, peak detection is performed on the target signal to determine the point with the highest matching amplitude value, i.e., the peak point in the target signal, as a second signal point. Then, one signal point adjacent to the second signal point before the second signal point is determined as a first signal point, and one signal point adjacent to the second signal point after the second signal point is determined as a third signal point.

[0103] In step 150, the measurement distance corresponding to the to-be-measured object is determined according to the first signal point, the second signal point, and the third signal point.

[0104] In this step, after the first signal point, the second signal point, and the third signal point are determined from the target signal, the measurement distance corresponding to the to-be-measured object can be determined according to the first signal point, the second signal point, and the third signal point. Specifically, in the embodiments of the present application, the following formula can be used to calculate the measurement distance:

[0105]

[0106] In the formula, d represents the calculated measurement distance, a is a constant parameter and can be 0.075, z1 represents the matching amplitude value corresponding to the first signal point, z2 represents the matching amplitude value corresponding to the second signal point, z3 represents the matching amplitude value corresponding to the third signal point, n1 represents the time point corresponding to the first signal point, n2 represents the time point corresponding to the second signal point, and n3 represents the time point corresponding to the third signal point. f

[0107] It can be understood that the laser ranging method provided in the embodiments of the present application can obtain a relatively accurate measurement distance result, has relatively high ranging accuracy and relatively fast measurement speed, has relatively low requirements on hardware devices, is conducive to reducing the implementation cost of laser ranging, has a simple processing process, and can improve the efficiency of ranging application.

[0108] In the embodiments of the present application, a laser ranging system is also provided, which is described with reference to Figure 2 , and the system comprises:

[0109] a processing unit, a laser driving unit, a laser emitting unit, a laser receiving unit, and a comparator unit; the processing unit is connected to the laser emitting unit through the laser driving unit, the laser receiving unit is connected to the comparator unit, and the comparator unit is connected to the processing unit.

[0110] The processing unit comprises a smoothing filter, a waveform matching filter, a peak detection module, and a distance calculation module.

[0111] ​The processing unit is configured to drive the laser emission unit to emit a chirp laser signal to a to-be-measured object through the laser driving unit;

[0112] The laser receiving unit is configured to receive a returned echo signal;

[0113] The comparator unit is configured to perform conversion processing on the echo signal to obtain a corresponding square wave signal based on a comparator threshold value;

[0114] The processing unit is further configured to perform smoothing filter processing on the square wave signal through the smoothing filter and perform matched filter processing on the signal after the smoothing filter processing through the waveform matched filter to obtain a target signal;

[0115] The peak detection module is configured to perform peak detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal; the second signal point is a peak point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a subsequent signal point of the second signal point;

[0116] The distance calculation module is configured to determine a measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point.

[0117] In some embodiments, the system described above can further include an amplifier unit, which can be arranged between the laser receiving unit and the comparator unit, and the amplifier unit can be configured to perform amplification processing on the echo signal.

[0118] It can be understood that, Figure 1 The contents of the laser ranging method embodiments shown are applicable to the laser ranging system embodiments, the laser ranging system embodiments specifically implement the functions of the Figure 1 laser ranging method embodiments shown, and achieve the same beneficial effects as the Figure 1 laser ranging method embodiments shown.

[0119] In the following, the implementation process of the laser ranging method provided in the present application will be described in combination with a specific embodiment.

[0120] Please refer to Figure 3 In the present embodiment, when implementing laser ranging, the specific process can include:

[0121] Step S11: The laser emission unit emits a chirp laser signal;

[0122] When measuring the distance to the object under test, the processing unit can control the laser emitting unit to emit a linear frequency modulated laser signal through the laser driving unit. This signal is a laser signal that alternates between high-level and low-level signals. In this embodiment, it can be expressed as: s(t)=[g(Δt1),g(Δt2),g(Δt3),…,g(Δt)2] i In the formula, s(t) represents the linear frequency modulated laser signal, i represents the number (a positive integer), and Δt... i G(Δt) represents the duration of the i-th signal segment (either a high-level or low-level signal). i ) represents the i-th signal segment (high-level signal or low-level signal). In the embodiments of this application, Δt i It is not a constant value; as i increases, Δt... i It can be that the frequency increases first and then decreases; conversely, the alternation frequency of high-level and low-level signals within a linearly frequency-modulated laser signal first decreases and then increases. Please refer to... Figure 4 , Figure 4 A schematic diagram of a linear frequency modulated laser signal is shown. Figure 4 The linear frequency modulated laser signal shown can be represented as s(t)=[0,1,0,1,0,1,0,1,0,1,0,1,0], where 0 represents a low-level signal, 1 represents a high-level signal, and Δt i =[14,14,15,20,30,77,30,20,15,14,14], from Figure 4 It can be seen that the alternation frequency of high-level signals and low-level signals first decreases, the duration of each level signal first increases, and then the alternation frequency of high-level signals and low-level signals increases again, while the duration of each level signal decreases accordingly.

[0123] Step S12: The laser receiving unit receives the echo signal;

[0124] The aforementioned linear frequency modulated laser signal is reflected by the object under test to form an echo signal. The laser receiving unit can receive the echo signal with noise. The echo signal can be expressed as: r(t)=h(t)s(t-τ)+η(t), where r(t) represents the echo signal, h(t) is the attenuation caused by the signal during propagation and reflection, the time delay of the time signal is τ, τ is the variable to be measured, and η(t) is the additive white Gaussian noise added to the channel.

[0125] Step S13: The amplifier unit amplifies the above echo signal to obtain the amplified echo signal y(t);

[0126] Step S14: The comparator unit converts the amplified echo signal y(t) into a square wave signal y(n);

[0127] Please refer to Figure 5 and Figure 6 , the comparator unit can compare the signal y(t) and output a square wave signal, specifically, the process can be represented as:

[0128]

[0129] Wherein, y(n) is a square wave signal, y(t) is an amplified echo signal (also can use echo signal r(t)), λ is the comparator threshold of the comparator unit. 0 represents a low level signal, and 1 represents a high level signal. In the embodiment of the application, y(n) is a 1-bit level signal, only indicating the high and low levels of the signal, without quantization information, greatly simplifying the complexity of subsequent signal processing.

[0130] Step S15: smoothing filtering the square wave signal;

[0131] The smoothing filter can smooth filter the square wave signal y(n) to obtain a signal x(n). In the embodiment of the application, the structure of the smoothing filter used is as shown in Figure 7 Because the comparator unit only outputs 0 and 1 level signals, the threshold is affected by noise and the process of setting the threshold, and the threshold is too high or too low, which will cause the output of the comparator unit to fluctuate, but the comparator threshold within a certain range will output 0 and 1 two alternating level signals, and the most critical feature of the transmitted linear frequency modulation laser signal is its frequency modulation characteristic, so the relative phase information of 0 and 1 signals is relatively sensitive, and the phase feature needs to be detected through smoothing filtering processing to remove random noise caused by noise channels. In the embodiment of the application, the signal is smoothed and filtered to obtain accurate phase information of the signal. The output signal after smoothing filtering processing is as shown in Figure 8 The output signal x(n) is no longer a 0 and 1 level signal, but a pulse signal with different amplitudes.

[0132] Step S16: the waveform matching filter matches the signal x(n) after smoothing filtering;

[0133] In the embodiment of the application, the structure of the waveform matching filter used is as shown in Figure 9 The waveform matching filter is used to correlate the signal x(n) with the pre-stored transmitted signal and output a sequence z(n), n∈[0, T stop ], so as to distinguish the received signal and noise signal in the signal x(n). The peak point of the sequence z(n) corresponds to the time delay, and the distance can be calculated from the time delay information, so as to accurately locate the time delay of the received signal relative to the transmitted signal. In the embodiment of the application, the sequence z(n) is recorded as a target signal.

[0134] Step S17: Peak detection, and output three points;

[0135] The peak detection module is used to estimate the precise timing point and timing peak information of the target signal z(n). The peak detection conditions are as follows: (1) the peak value should be 3-5 times greater than the average value of other parts, and (2) the signs of the slopes of the two points before and after the peak point should be opposite. The peak detection module outputs three points: the point before the peak point (first signal point), the peak point (second signal point), and the point after the peak point (third signal point), i.e., [(n1,z1),(n2,z2),(n3,z3)]. z1 represents the matching amplitude value corresponding to the first signal point, z2 represents the matching amplitude value corresponding to the second signal point, and z3 represents the matching amplitude value corresponding to the third signal point. n1 represents the time point corresponding to the first signal point, n2 represents the time point corresponding to the second signal point, and n3 represents the time point corresponding to the third signal point.

[0136] Reference Figure 10 and Figure 11 , Figure 10 This is a schematic diagram of the target signal z(n) obtained through matching. Figure 11 This is a schematic diagram showing the first, second, and third signal points found in the target signal.

[0137] Step S18: Calculate the measured distance.

[0138] After obtaining information from each signal point, the distance calculation module can calculate the precise location information using a formula. The specific formula is as follows:

[0139]

[0140] In the formula, d f The calculated measurement distance is represented by , where 'a' is a constant parameter that can be 0.075, z1 represents the matching amplitude value corresponding to the first signal point, z2 represents the matching amplitude value corresponding to the second signal point, z3 represents the matching amplitude value corresponding to the third signal point, n1 represents the time point corresponding to the first signal point, n2 represents the time point corresponding to the second signal point, and n3 represents the time point corresponding to the third signal point.

[0141] Specifically, in the embodiments of this application, the formula for measuring distance can be obtained through the following derivation process:

[0142]

[0143] In the formula, d f This represents the calculated distance, where c represents the speed of light and e represents 10.

[0144] Please refer to Figure 12 ,Figure 12 is a flowchart of another laser ranging method provided by an embodiment of the present application, referring to Figure 12 Another laser ranging method provided by the present application includes but is not limited to:

[0145] Step 1210, emitting a linear frequency modulation laser signal to a to-be-measured object, and receiving a returned echo signal;

[0146] Step 1220, performing conversion processing on the echo signal based on a comparator threshold value, to obtain a corresponding square wave signal;

[0147] Step 1230, performing smoothing filtering processing and matching filtering processing on the square wave signal, to obtain a target signal;

[0148] Step 1240, performing peak value detection on the target signal, to determine a first signal point, a second signal point and a third signal point from the target signal; wherein the second signal point is a peak value point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a subsequent signal point of the second signal point;

[0149] Step 1250, calculating signal-to-noise ratio data of the target signal;

[0150] Step 1260, if the signal-to-noise ratio data is greater than or equal to a preset threshold value, determining a measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point;

[0151] Step 1270, if the signal-to-noise ratio data is less than the preset threshold value, updating the comparator threshold value, and returning to the step of emitting a linear frequency modulation laser signal to a to-be-measured object and receiving a returned echo signal.

[0152] In an embodiment of the present application, another laser ranging method is provided, which is based on the method shown in Figure 1 , and provides a strategy for adjusting a comparator threshold value. The difference between the method and Figure 1 the method shown in mainly lies in steps 1250 to 1270, which will be described below, Figure 12 the same steps in the method and Figure 1 the method shown in the present application will not be described.

[0153] In an embodiment of the present application, when measuring a to-be-measured object, the comparator threshold value can be adjusted to adapt to different situations. Specifically, after obtaining a target signal, signal-to-noise ratio data of the target signal can be calculated, and the specific formula is as follows:

[0154]

[0155] In the formula, SNR represents signal-to-noise ratio data, z(n) represents a target signal, max(z(n)) represents a peak value in the target signal, and λ represents a comparator threshold value.

[0156] After obtaining the signal-to-noise ratio data, the signal-to-noise ratio data can be compared with a preset threshold value. The preset threshold value can be set to 10 dB or other sizes, and the present application does not limit this. Then, if the signal-to-noise ratio data is greater than or equal to the preset threshold value, the measured distance can be normally calculated, and the process is similar to the foregoing step 140; if the signal-to-noise ratio data is less than the preset threshold value, the comparator threshold value can be updated, and the process returns to step 1210, and steps 1210 to 1250 are executed again in sequence until the condition of step 1260 is met.

[0157] Specifically, in the embodiment of the present application, when the comparator threshold value is updated, the following formula can be used:

[0158]

[0159] In the formula, λ2 represents the updated comparator threshold value, z(n) represents the target signal, max(z(n)) represents the peak value in the target signal, and λ1 represents the comparator threshold value before updating.

[0160] Correspondingly, the present application also provides a laser ranging system, which refers to Figure 13 , and the system comprises:

[0161] a processing unit, a laser driving unit, a laser emitting unit, a laser receiving unit, and a comparator unit; the processing unit is connected to the laser emitting unit through the laser driving unit, the laser receiving unit is connected to the comparator unit, and the comparator unit is connected to the processing unit;

[0162] The processing unit comprises a smoothing filter, a waveform matching filter, a peak value detection module, a signal-to-noise ratio calculation module, a distance calculation module, and a comparator threshold value control module.

[0163] The processing unit is configured to drive the laser emitting unit to emit a linear frequency modulation laser signal to a to-be-measured object through the laser driving unit.

[0164] The laser receiving unit is configured to receive a returned echo signal.

[0165] The comparator unit is configured to perform conversion processing on the echo signal based on a comparator threshold value to obtain a corresponding square wave signal.

[0166] The processing unit is further configured to perform smoothing filtering on the square wave signal through the smoothing filter, and perform matching filtering on the signal after the smoothing filtering through the waveform matching filter to obtain a target signal.

[0167] The peak detection module is configured to perform peak detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal, wherein the second signal point is a peak point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a subsequent signal point of the second signal point.

[0168] The signal-to-noise ratio calculation module is configured to calculate signal-to-noise ratio data of the target signal.

[0169] The distance calculation module is configured to determine a measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point.

[0170] The comparator threshold control module is configured to update the comparator threshold.

[0171] It can be understood that, Figure 12 The contents of the laser ranging method embodiments shown are applicable to the laser ranging system embodiments, the laser ranging system embodiments specifically implement the functions and Figure 12 The laser ranging system embodiments achieve the same beneficial effects as the laser ranging method embodiments shown, and the laser ranging system embodiments achieve the same beneficial effects as the laser ranging method embodiments shown. Figure 12

[0172] Refer to Figure 14 In some embodiments, the processing unit includes a first processing unit and a second processing unit; the first processing unit adopts a programmable logic array logic chip, and the second processing unit adopts a single-chip microcomputer chip; the first processing unit and the second processing unit are connected in communication through a serial peripheral interface;

[0173] The first processing unit includes the smoothing filter, the waveform matching filter, the peak detection module, the signal-to-noise ratio calculation module and the distance calculation module; and the second processing unit includes the comparator threshold control module.

[0174] In the embodiments of the present application, the architecture of the laser ranging system can adopt a dual-processing unit architecture of a programmable logic array logic chip and a single-chip microcomputer chip (FPGA + single-chip microcomputer), and the respective advantages of the FPGA and the single-chip microcomputer are used to execute corresponding software function modules, as follows:

[0175] ​The processing unit can include a first processing unit and a second processing unit, the first processing unit is a FPGA (Field Programmable Gate Array, Field Programmable Gate Array) chip, and the second processing unit is a single-chip microcomputer (Single-Chip Microcomputer) chip. The first processing unit can include a smoothing filter, a waveform matching filter, a peak detection module, a signal-to-noise ratio calculation module, and a distance calculation module. The second processing unit can include a comparator threshold control module. The first processing unit and the second processing unit communicate through an SPI interface (Serial Peripheral Interface, Chinese: Serial Peripheral Interface). The performance of the FPGA is suitable for signal processing operations such as smoothing filtering and waveform matching filtering, and the performance of the single-chip microcomputer is suitable for display module control and comparator threshold control. Based on the above architecture, the performance of each chip can be better.

[0176] Please refer to Figure 15 , Figure 15 is another flowchart of a laser ranging method provided by the embodiments of the present application, referring to Figure 15 , another laser ranging method provided by the present application includes but is not limited to:

[0177] Step 1510, receiving an ambient noise signal without emitting a linear frequency modulation laser signal;

[0178] Step 1520, ADC sampling the ambient noise signal to obtain a first signal;

[0179] Step 1530, determining an initialized comparator threshold value according to the first signal;

[0180] Step 1540, emitting a linear frequency modulation laser signal to the object to be measured and receiving a returned echo signal;

[0181] Step 1550, based on the comparator threshold value, converting and processing the echo signal to obtain a corresponding square wave signal;

[0182] Step 1560, filtering the square wave signal to obtain a target signal;

[0183] Step 1570, performing peak detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal; wherein the second signal point is a peak point in the target signal, the first signal point is a signal point before the second signal point, and the third signal point is a signal point after the second signal point;

[0184] Step 1580, calculating the signal-to-noise ratio data of the target signal;

[0185] Step 1590, if the signal-to-noise ratio data is greater than or equal to a preset threshold, determining the measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point;

[0186] Step 1500, if the signal-to-noise ratio data is less than the preset threshold, updating the comparator threshold, and returning to the step of emitting the linear frequency modulation laser signal to the to-be-measured object and receiving the returned echo signal.

[0187] The method provides a strategy for initializing the comparator threshold on the basis of the method shown in Figure 12 The difference between the method and the method shown in Figure 12 The difference between the method and the method shown in Figure 15 The difference between the method and the method shown in Figure 12 The difference between the method and the method shown in

[0188] In the embodiment of the application, when the to-be-measured object is measured, the comparator threshold can be initialized according to the environmental noise to adapt to different situations. Specifically, the environmental noise signal can be received without emitting the linear frequency modulation laser signal after starting the machine, and then the environmental noise signal is subjected to ADC sampling to obtain the first signal q(t); then, the initialized comparator threshold can be determined according to the first signal q(t).

[0189] Specifically, the noise level of the first signal can be calculated in the embodiment of the application, and the formula is as follows:

[0190]

[0191] In the formula, ε represents the noise level, N represents the number of signal points in the first signal, n represents the signal point number (starting from 0) in the first signal, and q(t) represents the first signal. Then, the initialized comparator threshold can be set as follows:

[0192] λ0=bε

[0193] In the formula, λ0 represents the initialized comparator threshold, ε represents the noise level, and b is a constant, which can be 2.

[0194] Correspondingly, the embodiment of the application also provides a laser ranging system, which refers to Figure 16 The system comprises:

[0195] a processing unit, a laser driving unit, a laser emitting unit, a laser receiving unit and a comparator unit; the processing unit is connected to the laser emitting unit through the laser driving unit, the laser receiving unit is connected to the comparator unit, and the comparator unit is connected to the processing unit.

[0196] The processing unit comprises a smoothing filter, a waveform matching filter, a peak detection module, a signal-to-noise ratio calculation module, a distance calculation module, an ADC sampling module, a comparator threshold calculation module and a comparator threshold control module;

[0197] The processing unit is configured to drive the laser emission unit to emit a linear frequency modulation laser signal to a to-be-measured object through the laser driving unit;

[0198] The laser receiving unit is configured to receive a returned echo signal and an environmental noise signal in the case where no linear frequency modulation laser signal is emitted;

[0199] The comparator unit is configured to perform conversion processing on the echo signal based on a comparator threshold to obtain a corresponding square wave signal;

[0200] The processing unit is further configured to perform smoothing filter processing on the square wave signal through the smoothing filter and perform matching filter processing on the signal after the smoothing filter processing through the waveform matching filter to obtain a target signal;

[0201] The peak detection module is configured to perform peak detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal; wherein the second signal point is a peak point in the target signal, the first signal point is a previous signal point of the second signal point, and the third signal point is a subsequent signal point of the second signal point;

[0202] The signal-to-noise ratio calculation module is configured to calculate signal-to-noise ratio data of the target signal;

[0203] The distance calculation module is configured to determine a measurement distance corresponding to the to-be-measured object according to the first signal point, the second signal point and the third signal point;

[0204] The ADC sampling module is configured to perform ADC sampling on the environmental noise signal to obtain a first signal;

[0205] The comparator threshold calculation module is configured to determine an initialized comparator threshold according to the first signal;

[0206] The comparator threshold control module is configured to adjust the comparator threshold according to the initialized comparator threshold.

[0207] It can be understood that, Figure 15 The contents in the laser ranging method embodiment shown are applicable to the laser ranging system embodiment, and the laser ranging system embodiment specifically implements the functions and advantages of the laser ranging method embodiment. Figure 15The laser ranging method embodiments shown are the same, and the beneficial effects achieved are the same. Figure 15 The beneficial effects achieved by the laser ranging method embodiments shown are also the same.

[0208] Referring to Figure 17 In some embodiments, the processing unit includes a first processing unit and a second processing unit; the first processing unit uses a programmable logic array logic chip, and the second processing unit uses a single-chip microcomputer chip; the first processing unit and the second processing unit are connected in communication through a serial peripheral interface;

[0209] The first processing unit includes the smoothing filter, the waveform matching filter, the peak detection module, the signal-to-noise ratio calculation module, and the distance calculation module; the second processing unit includes the ADC sampling module, the comparator threshold calculation module, and the comparator threshold control module.

[0210] In the embodiments of the present application, and the foregoing Figure 14 Similarly, the architecture of the laser ranging system can use a dual-processing unit architecture of a programmable logic array logic chip and a single-chip microcomputer chip (FPGA + single-chip microcomputer), and Figure 14 The difference between the present application and the foregoing lies in that, in the embodiments of the present application, the second processing unit further includes an ADC sampling module and a comparator threshold calculation module, and the performance of the single-chip microcomputer is suitable for the calculation of the noise level and the comparator threshold, and the single-chip microcomputer is provided with an ADC sampling module, so that an additional ADC does not need to be configured, and the overall cost of the system can be reduced. Based on the above architecture, the better performance of each chip can be brought out.

[0211] The embodiments of the present application further disclose a laser ranging device, which includes:

[0212] at least one processor;

[0213] at least one memory for storing at least one program;

[0214] When the at least one program is executed by the at least one processor, the at least one processor implements the functions as Figure 1 , Figure 12 or Figure 15 a laser ranging method embodiment shown.

[0215] It can be understood that the contents in the laser ranging method embodiments shown as Figure 1 , Figure 12 or Figure 15 are all applicable to the present laser ranging device embodiments, and the functions specifically implemented by the present laser ranging device embodiments are the same as those in the laser ranging method embodiments shown as Figure 1 , Figure 12 or Figure 15The embodiments of the laser ranging method shown have the same beneficial effects and achieve the same beneficial effects as the embodiments of the laser ranging method shown in Figure 1 、 Figure 12 or Figure 15 .

[0216] The embodiments of the computer readable storage medium disclosed in the present application store a program executable by a processor, and the program executable by the processor is used to implement the embodiments of the laser ranging method shown in Figure 1 、 Figure 12 or Figure 15 .

[0217] It can be understood that the contents in the embodiments of the laser ranging method shown in Figure 1 、 Figure 12 or Figure 15 are all applicable to the embodiments of the computer readable storage medium, the functions implemented by the embodiments of the computer readable storage medium are the same as the embodiments of the laser ranging method shown in Figure 1 、 Figure 12 or Figure 15 , and the beneficial effects achieved by the embodiments of the laser ranging method shown in Figure 1 、 Figure 12 or Figure 15 Figure 1 Figure 12 Figure 15 .

[0218] In some alternative embodiments, the functions / operations mentioned in the block diagram can not occur in the order mentioned in the operation diagram. For example, depending on the functions / operations involved, two blocks shown in succession can actually be executed substantially simultaneously or the blocks can sometimes be executed in reverse order. In addition, the embodiments presented and described in the flowcharts of the present application are provided by way of example, and the purpose is to provide a more comprehensive understanding of the technology. The disclosed method is not limited to the operations and logical flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and in which sub-operations described as part of larger operations are independently executed.

[0219] Furthermore, although the present application is described in the context of functional modules, it is understood that one or more of the functions and / or features can be integrated in a single physical system and / or software module, or one or more functions and / or features can be implemented in separate physical systems or software modules. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary to an understanding of the present application. Rather, the actual implementation is within the routine skill of those in the art, given the nature of the property, functions and internal relationships of the various functional modules disclosed herein. Therefore, the present application is not limited to the specific embodiments described herein, but only by the scope of the appended claims, along with their equivalents.

[0220] If the functions are implemented in software, the functions can be stored in or implemented as one or more computer program products. The computer program product can be stored in a computer readable medium, which can include, but is not limited to, RAM, ROM, electrically programmable ROM (EPROM or EEPROM), flash memory, or a magnetic or optical card, or any suitable device used for storing computer program codes, which can be read by the mobile terminal, computer, or magnetic or optical card reader.

[0221] The logic and / or steps represented in the flowcharts and / or described herein, for example, can be embodied in non-transitory computer-readable media, which can be executed by an instruction execution system, apparatus or device (such as a computer-based system, a processor- based system, or other system that can fetch the instructions from the instruction execution system, apparatus or device and execute the instructions), or in conjunction with such an instruction execution system, apparatus or device. For the purposes of this specification, a "computer-readable medium" can be any system, apparatus, or device that can include, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

[0222] More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can also be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, for example, via optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

[0223] It should be understood that aspects of the application can be implemented in hardware, software, firmware or combinations thereof. In the above embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies, or combinations thereof, can be used with the necessary hardware: discrete logic circuitry having logic gates for implementing logic functions upon an application of data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and so forth.

[0224] In the above description of the present specification, reference to the description of the terms "one embodiment / one example", "another embodiment / another example" or "certain embodiments / certain examples" and the like means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present specification. The illustrative representations of the above terms in the present specification do not necessarily refer to the same embodiment or example. Also, the described particular features, structures, materials or characteristics can be combined in any appropriate manner in one or more embodiments or examples.

[0225] Although embodiments of the present application have been shown and described, it would be recognized by those of ordinary skill in the art that various changes, modifications, alternatives, and variations can be made thereto without departing from the spirit and scope of the application, which should be limited only by the scope of the claims and the equivalents thereof.

[0226] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application

[0227] In the description of the specification, reference to "one embodiment", "another embodiment" or "certain embodiments" etc. means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0228] Although the embodiments of the present application have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations to these embodiments could be made without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A laser ranging method, characterized by, The method comprises: receiving an ambient noise signal without emitting a linear frequency modulation laser signal; performing ADC sampling on the ambient noise signal to obtain a first signal; determining an initialized comparator threshold value according to the first signal; emitting a linear frequency modulation laser signal to a to-be-measured object and receiving a returned echo signal; performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal; performing smoothing filter processing and matching filter processing on the square wave signal to obtain a target signal; performing peak value detection on the target signal to determine a first signal point, a second signal point and a third signal point from the target signal; the second signal point is a peak value point in the target signal, the first signal point is a signal point adjacent to the front of the second signal point, and the third signal point is a signal point adjacent to the rear of the second signal point; calculating signal-to-noise ratio data of the target signal; if the signal-to-noise ratio data is greater than or equal to a preset threshold value, determining a measurement distance corresponding to the to-be-measured object through the following formula: In the formula, d f represents a calculated measurement distance, a is a constant parameter determined based on the speed of light, z1 represents a matching amplitude value corresponding to the first signal point, z2 represents a matching amplitude value corresponding to the second signal point, z3 represents a matching amplitude value corresponding to the third signal point, n1 represents a time point corresponding to the first signal point, n2 represents a time point corresponding to the second signal point, and n3 represents a time point corresponding to the third signal point. Or, if the signal-to-noise ratio data is less than the preset threshold value, updating the comparator threshold value, and returning to the step of emitting a linear frequency modulation laser signal to a to-be-measured object and receiving a returned echo signal.

2. The laser ranging method of claim 1, wherein, Before the step of performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal, the method further comprises: performing amplification processing on the echo signal.

3. The method of claim 1, wherein, The linear frequency modulation laser signal is a laser signal in which high-level signals and low-level signals alternate, and the alternating frequency of the high-level signals and the low-level signals in the linear frequency modulation laser signal first decreases and then increases.

4. The method of claim 1, wherein, The step of performing conversion processing on the echo signal based on the comparator threshold value to obtain a corresponding square wave signal comprises: comparing each to-be-converted signal point on the echo signal with the comparator threshold value; if the amplitude of the to-be-converted signal point is less than the comparator threshold value, adjusting the to-be-converted signal point to a low-level signal point, or if the amplitude of the to-be-converted signal point is greater than or equal to the comparator threshold value, adjusting the to-be-converted signal point to a high-level signal point.

5. The method of claim 1, wherein, The step of calculating the signal-to-noise ratio data of the target signal comprises: calculating the signal-to-noise ratio data of the target signal through the following formula: wherein SNR represents the signal-to-noise ratio data, z(n) represents the target signal, max(z(n)) represents the peak value in the target signal, and λ represents the comparator threshold value.

6. The method of claim 1, wherein, The step of updating the comparator threshold value comprises: updating the comparator threshold value through the following formula: wherein λ2 represents the updated comparator threshold value, z(n) represents the target signal, max(z(n)) represents the peak value in the target signal, and λ1 represents the comparator threshold value before updating.

7. The method of claim 1, wherein, The step of determining an initialized comparator threshold value according to the first signal comprises: calculating the noise level of the first signal through the following formula: wherein ε represents the noise level, N represents the number of signal points in the first signal, n represents the signal point number in the first signal, and q(t) represents the first signal. According to the noise level, an initialized comparator threshold is determined by the following formula: λ0=bε In the formula, λ0 represents the initialized comparator threshold, ε represents the noise level, and b is a constant.

8. A laser ranging system characterized by, The system comprises: a processing unit, a laser driving unit, a laser emitting unit, a laser receiving unit, and a comparator unit; the processing unit is connected to the laser emitting unit through the laser driving unit, the laser receiving unit is connected to the comparator unit, and the comparator unit is connected to the processing unit; the processing unit comprises a smoothing filter, a waveform matching filter, a peak detection module, a signal-to-noise ratio calculation module, a distance calculation module, an ADC sampling module, a comparator threshold calculation module, and a comparator threshold control module; the processing unit is configured to drive the laser emitting unit to emit a linear frequency modulation laser signal to a to-be-measured object through the laser driving unit; the laser receiving unit is configured to receive a returned echo signal and an environmental noise signal in the absence of the linear frequency modulation laser signal; the comparator unit is configured to perform conversion processing on the echo signal based on a comparator threshold to obtain a corresponding square wave signal; the processing unit is further configured to perform smoothing filter processing on the square wave signal through the smoothing filter, and perform matching filter processing on the signal after the smoothing filter processing through the waveform matching filter to obtain a target signal; the peak detection module is configured to perform peak detection on the target signal to determine a first signal point, a second signal point, and a third signal point from the target signal; the second signal point is a peak point in the target signal, the first signal point is a signal point adjacent to the front of the second signal point, and the third signal point is a signal point adjacent to the rear of the second signal point; the signal-to-noise ratio calculation module is configured to calculate signal-to-noise ratio data of the target signal; the distance calculation module is configured to determine a measurement distance corresponding to the to-be-measured object through the following formula: In the formula, d f represents a calculated measurement distance, a is a constant parameter determined based on the speed of light, z1 represents a matching amplitude value corresponding to the first signal point, z2 represents a matching amplitude value corresponding to the second signal point, z3 represents a matching amplitude value corresponding to the third signal point, n1 represents a time point corresponding to the first signal point, n2 represents a time point corresponding to the second signal point, and n3 represents a time point corresponding to the third signal point. the ADC sampling module is configured to perform ADC sampling on the environmental noise signal to obtain a first signal; the comparator threshold calculation module is configured to determine an initialized comparator threshold according to the first signal; the comparator threshold control module is configured to adjust the comparator threshold according to the initialized comparator threshold.

9. A laser ranging system according to claim 8, wherein, The processing unit comprises a first processing unit and a second processing unit; the first processing unit adopts a programmable logic array logic chip, and the second processing unit adopts a single-chip microcomputer chip; the first processing unit and the second processing unit are connected in communication through a serial peripheral interface; the first processing unit comprises the smoothing filter, the waveform matching filter, the peak detection module, the signal-to-noise ratio calculation module, and the distance calculation module; the second processing unit comprises the ADC sampling module, the comparator threshold calculation module, and the comparator threshold control module.

10. A laser ranging device, characterized by, The device comprises: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor is caused to implement the laser ranging method according to any one of claims 1 to 7.

11. A computer readable storage medium, characterized in that, A non-transitory computer readable medium having stored thereon processor-executable program, the processor-executable program, when executed by a processor, for implementing the laser ranging method according to any one of claims 1 to 7.

Images