A signal noise filtering method, device, storage medium and laser radar

Abstract

A signal noise filtering method, device, storage medium and laser radar, wherein the method comprises: acquiring an initial beat frequency signal generated by the laser radar (S101), the initial beat frequency signal being a beat frequency signal containing noise signals; performing at least one autocorrelation processing on the initial beat frequency signal to obtain a useful signal of the initial beat frequency signal (S102); and determining the useful signal as a de-noised time-domain beat frequency signal (S103). The signal-to-noise ratio of the beat frequency signal can be improved, and the success rate of effective beat frequency extraction can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computers, and in particular to a signal noise filtering method and device, a storage medium, and a laser radar. BACKGROUND

[0002] Frequency Modulated Continuous Wave (FMCW) laser radar belongs to a kind of continuous wave laser radar based on coherent detection, emits continuous wave with linearly varying frequency as transmitting signal in sweep period, part of transmitting signal is used as local signal, and the rest is emitted outward for detection, and the echo signal returned after being reflected by an object forms a beat signal with the local signal. Due to the influence of inherent noise such as laser radar system and environment in the actual detection process, the signal-to-noise ratio is low, and the effective beat signal cannot be extracted well. SUMMARY

[0003] The embodiments of the present application provide a signal noise filtering method, device, storage medium and laser radar, which can improve the signal-to-noise ratio of the beat signal and improve the success rate of extracting the effective beat frequency.

[0004] The embodiments of the present application provide a signal noise filtering method, device, storage medium and laser radar, which can improve the signal-to-noise ratio of the beat signal and improve the success rate of extracting the effective beat frequency.

[0005] An initial beat signal generated by a laser radar is obtained, and the initial beat signal is a beat signal containing noise signals.

[0006] At least one autocorrelation processing is performed on the initial beat signal to obtain a useful signal of the initial beat signal.

[0007] The useful signal is determined as a time-domain beat signal after noise reduction.

[0008] The at least one autocorrelation processing performed on the initial beat signal to obtain the useful signal of the initial beat signal includes:

[0009] Autocorrelation processing is performed on the initial beat signal to obtain a first autocorrelation function of the initial beat signal.

[0010] Autocorrelation processing is performed on the first autocorrelation function to obtain a useful signal corresponding to the initial beat signal.

[0011] The at least one autocorrelation processing performed on the initial beat signal to obtain the useful signal of the initial beat signal includes:

[0012] Autocorrelation processing is performed on the initial beat signal to obtain a second autocorrelation function of the initial beat signal.

[0013] determining the second autocorrelation function as the initial beat frequency signal when a first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to a signal-to-noise threshold, and turning to perform the step of performing autocorrelation processing on the initial beat frequency signal to obtain a second autocorrelation function of the initial beat frequency signal until the first signal-to-noise ratio is greater than the signal-to-noise threshold, and determining the second autocorrelation function as a useful signal corresponding to the initial beat frequency signal.

[0014] The performing autocorrelation processing on the initial beat frequency signal to obtain a useful signal of the initial beat frequency signal comprises:

[0015] performing autocorrelation processing on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and updating a processing number of the autocorrelation processing;

[0016] determining the third autocorrelation function as the initial beat frequency signal when a second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to a signal-to-noise threshold and the processing number is less than a number threshold, and turning to perform the step of performing autocorrelation processing on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and updating a processing number of the autocorrelation processing;

[0017] determining the third autocorrelation function as a useful signal corresponding to the initial beat frequency signal when the second signal-to-noise ratio indicated by the third autocorrelation function is greater than the signal-to-noise threshold and the processing number is less than the number threshold;

[0018] determining the third autocorrelation function as a useful signal corresponding to the initial beat frequency signal when the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold and the processing number is equal to the number threshold.

[0019] The determining the useful signal as the denoised time-domain beat frequency signal comprises:

[0020] determining the useful signal as the denoised time-domain beat frequency signal when a target signal-to-noise ratio indicated by the useful signal is greater than the signal-to-noise threshold.

[0021] The method further comprises:

[0022] performing Fourier transform processing on the time-domain beat frequency signal to obtain a frequency-domain beat frequency signal, and obtaining a beat frequency value corresponding to a maximum amplitude in the frequency-domain beat frequency signal.

[0023] The application embodiment provides a signal noise filtering device, comprising:

[0024] An initial signal acquisition unit is configured to acquire an initial beat signal generated by the laser radar, the initial beat signal being a beat signal containing a noise signal;

[0025] A signal processing unit is configured to perform autocorrelation processing on the initial beat signal at least once to obtain a useful signal of the initial beat signal;

[0026] A de-noising signal determination unit is configured to determine the useful signal as a de-noised time-domain beat signal.

[0027] The signal processing unit includes:

[0028] A first signal processing sub-unit is configured to perform autocorrelation processing on the initial beat signal to obtain a first autocorrelation function of the initial beat signal;

[0029] A function processing sub-unit is configured to perform autocorrelation processing on the first autocorrelation function to obtain the useful signal corresponding to the initial beat signal.

[0030] The signal processing unit includes:

[0031] The signal processing unit includes:

[0032] A second signal processing sub-unit is configured to perform autocorrelation processing on the initial beat signal to obtain a second autocorrelation function of the initial beat signal;

[0033] A first notification sub-unit is configured to determine the second autocorrelation function as the initial beat signal when a first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to a signal-to-noise threshold, and notify the second signal processing sub-unit to perform autocorrelation processing on the initial beat signal to obtain a second autocorrelation function of the initial beat signal until the first signal-to-noise ratio is greater than the signal-to-noise threshold, and determine the second autocorrelation function as the useful signal corresponding to the initial beat signal.

[0034] The signal processing unit includes:

[0035] A third signal processing sub-unit is configured to perform autocorrelation processing on the initial beat signal to obtain a third autocorrelation function of the initial beat signal, and update a processing number of the autocorrelation processing;

[0036] A second notification sub-unit is configured to determine the third autocorrelation function as the initial beat signal when a second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to a signal-to-noise threshold, and the processing number is less than a number threshold, and notify the third signal processing sub-unit to perform autocorrelation processing on the initial beat signal to obtain a third autocorrelation function of the initial beat signal, and update a processing number of the autocorrelation processing;

[0037] The signal determination subunit is configured to determine the third autocorrelation function as the useful signal corresponding to the initial beat frequency signal when the second signal-to-noise ratio indicated by the third autocorrelation function is greater than a signal-to-noise threshold and the processing number is less than a number threshold.

[0038] The signal determination subunit is further configured to determine the third autocorrelation function as the useful signal corresponding to the initial beat frequency signal when the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold and the processing number is equal to the number threshold.

[0039] The de-noised signal determination unit is configured to determine the useful signal as the de-noised time-domain beat frequency signal when a target signal-to-noise ratio indicated by the useful signal is greater than a signal-to-noise threshold.

[0040] The method further includes:

[0041] The beat frequency acquisition unit is configured to perform Fourier transform processing on the time-domain beat frequency signal to obtain a frequency-domain beat frequency signal, and acquire a beat frequency value corresponding to a maximum amplitude in the frequency-domain beat frequency signal.

[0042] The embodiment of the present application provides a computer storage medium, which stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, the method steps described above are performed.

[0043] The embodiment of the present application provides a laser radar, which includes a processor, a memory, and an input-output interface.

[0044] The processor is connected to the memory and the input-output interface. The input-output interface is configured to perform page interaction. The memory is configured to store program codes. The processor is configured to call the program codes to perform the method steps described above.

[0045] In the embodiment of the present application, the initial beat frequency signal containing a noise signal generated by the laser radar is acquired. The initial beat frequency signal is processed at least once to obtain a useful signal of the initial beat frequency signal. Finally, the useful signal is determined as a de-noised time-domain beat frequency signal. Through at least one autocorrelation processing, the initial beat frequency signal can be processed into an autocorrelation function based on the signal correlation degree. The signal-to-noise ratio of the signal is effectively improved. The weak useful signal in the initial beat frequency signal is extracted. The success rate of extracting the effective beat frequency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0047] Figure 1 It is a system architecture diagram of signal noise filtering provided by the embodiments of the present application.

[0048] Figure 2 It is a flowchart of a signal noise filtering method provided by the embodiments of the present application.

[0049] Figure 3 It is a flowchart of a signal noise filtering method provided by the embodiments of the present application.

[0050] Figure 4 It is a flowchart of a signal noise filtering method provided by the embodiments of the present application.

[0051] Figure 5 It is a flowchart of a signal noise filtering method provided by the embodiments of the present application.

[0052] Figure 6 It is an example diagram of the frequency spectrum after Fourier transform of the signal provided by the embodiments of the present application.

[0053] Figure 7 It is an example diagram of the success rate of extracting useful signals of the signal under different signal-to-noise ratios provided by the embodiments of the present application.

[0054] Figure 8 It is an example diagram of the number of successful times of extracting useful signals under different detection distances and different signal-to-noise ratios provided by the embodiments of the present application.

[0055] Figure 9 It is a structural diagram of a signal noise filtering device provided by the embodiments of the present application.

[0056] Figure 10 It is a structural diagram of a signal noise filtering device provided by the embodiments of the present application.

[0057] Figure 11 It is a structural diagram of a signal processing unit provided by the embodiments of the present application.

[0058] Figure 12 It is a structural diagram of a signal processing unit provided by the embodiments of the present application.

[0059] Figure 13is a structural schematic diagram of a signal processing unit provided by an embodiment of the present application.

[0060] Figure 14 is a structural schematic diagram of a laser radar provided by an embodiment of the present application. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0062] Please combine Figures 1-8 the embodiments, the signal noise filtering method provided by the embodiments of the present application will be described in detail.

[0063] Please refer to Figure 1 , a system architecture diagram of signal noise filtering is provided by an embodiment of the present application. As shown in Figure 1 , the embodiments of the present application can be applied to the scene of laser radar detection, for example: environmental monitoring, spaceflight, communication, automatic driving navigation, positioning and other detection scenes. The transmission signal of the laser radar changes periodically according to the rule of triangular wave, performs signal transmission on the detection target, receives the echo signal returned by the detection target, and obtains the initial difference frequency signal formed by the transmission signal and the echo signal. The initial difference frequency signal can be processed by a signal processor through a series of signal processing processes, including analog-digital conversion processing, signal filtering processing, signal data extraction, signal data calculation and the like. Then, the signal spectrum and data generated by the signal processor are stored, displayed and managed by a background management device.

[0064] Since the emission signal and the echo signal are susceptible to inherent noise of a laser radar system, an environment, etc., an initial beat frequency signal with noise signals is presented in a spectrum, and embodiments of the present application specifically propose a signal noise filtering device in order to remove the noise signals in the initial beat frequency signal. The signal noise filtering device can be arranged in the signal processor or can be used as a stand-alone device to realize noise filtering processing of the initial beat frequency signal. The signal noise filtering device can acquire an initial beat frequency signal generated by a laser radar, the initial beat frequency signal being a beat frequency signal containing noise signals. The signal noise filtering device performs at least one autocorrelation processing on the initial beat frequency signal to obtain a useful signal of the initial beat frequency signal, and determines the useful signal as a time-domain beat frequency signal after noise removal.

[0065] Based on the system architecture of Figure 1 , please see Figure 2 , a flowchart of a signal noise filtering method is provided for embodiments of the present application. As shown in Figure 2 , the method of embodiments of the present application can include the following steps S101-S103.

[0066] S101, acquiring an initial beat frequency signal generated by a laser radar;

[0067] Specifically, the emission signal of the laser radar periodically changes according to the law of a triangular wave, performs signal emission on a detection target, and receives an echo signal returned by the detection target. Since the emission signal and the echo signal are susceptible to inherent noise of a laser radar system, an environment, etc., an initial beat frequency signal with noise signals is presented in a spectrum, and the signal noise filtering device acquires the initial beat frequency signal generated by the laser radar, the initial beat frequency signal being a beat frequency signal containing noise signals.

[0068] S102, performing at least one autocorrelation processing on the initial beat frequency signal to obtain a useful signal of the initial beat frequency signal;

[0069] Specifically, the signal noise filtering device can perform at least one autocorrelation processing on the initial beat frequency signal to obtain the useful signal of the initial beat frequency signal. It can be understood that the signal-to-noise ratio can be improved by autocorrelation operation. Therefore, in the optional implementation manner of the embodiment of the present application, the signal noise filtering device can further improve the signal-to-noise ratio of the initial beat frequency signal in two ways, i.e., twice autocorrelation processing and at least one autocorrelation processing convergence. The twice autocorrelation processing is twice autocorrelation operation processing on the initial beat frequency signal. The at least one autocorrelation processing convergence can be one or more repeated autocorrelation operation processing on the initial beat frequency signal until the signal-to-noise ratio indicated by the autocorrelation function obtained by operation meets the signal-to-noise threshold, and then the autocorrelation function obtained by the last autocorrelation operation processing is determined as the useful signal. The at least one autocorrelation processing convergence can also be provided with a number threshold of autocorrelation processing. During the one or more repeated autocorrelation operation processing on the initial beat frequency signal, if the signal-to-noise ratio indicated by the autocorrelation function does not meet the signal-to-noise threshold all the time, but the number of autocorrelation processing meets the number threshold, then the autocorrelation function obtained by the last autocorrelation operation processing is determined as the useful signal. Both the two ways can improve the signal-to-noise ratio of the initial beat frequency signal and effectively extract the useful signal.

[0070] S103, determining the useful signal as the denoised time domain beat frequency signal;

[0071] Specifically, the signal noise filtering device can determine the useful signal as the de-noised time-domain beat frequency signal. It can be understood that, in order to further ensure that the useful signal can be extracted, the signal noise filtering device can detect whether the target signal-to-noise ratio indicated by the useful signal is greater than a signal-to-noise threshold. The signal-to-noise threshold can be set according to actual conditions. When the target signal-to-noise ratio indicated by the useful signal is greater than the signal-to-noise threshold, the signal noise filtering device can determine the useful signal as the de-noised time-domain beat frequency signal. Of course, whether the target signal-to-noise ratio detection process needs to be performed can be determined according to actual conditions. For example, for the initial beat frequency signal containing a useful signal with high intensity, only one autocorrelation processing is required to effectively improve the signal-to-noise ratio. For the initial beat frequency signal containing a useful signal with general intensity, after twice autocorrelation processing, the signal-to-noise ratio can be effectively improved, and at this time, the target signal-to-noise ratio detection can not be performed. For the initial beat frequency signal containing a weak useful signal, whether the twice autocorrelation processing or the at least one autocorrelation processing convergence mode is used, the target signal-to-noise ratio detection needs to be performed to ensure that the target signal-to-noise ratio meets certain requirements (for example, greater than the signal-to-noise threshold) so as to facilitate subsequent extraction of the beat frequency of the useful signal. Of course, for the initial beat frequency signal containing a weak useful signal, while the target signal-to-noise ratio detection is performed, the number of autocorrelation processing times can also be detected to limit the number of processing times to a certain range (for example, equal to the number threshold) in the case that the target signal-to-noise ratio still cannot meet certain requirements, so as to ensure the processing efficiency of the extraction of the beat frequency of the useful signal.

[0072] In the embodiment of the present application, by acquiring the initial beat frequency signal containing noise signals generated by the laser radar, at least one autocorrelation processing can be performed on the initial beat frequency signal to obtain the useful signal of the initial beat frequency signal, and finally the useful signal is determined as the de-noised time-domain beat frequency signal. Through at least one autocorrelation processing, the initial beat frequency signal can be processed into an autocorrelation function based on the signal correlation degree, effectively improving the signal-to-noise ratio of the signal, extracting the weak useful signal in the initial beat frequency signal, and further improving the success rate of effective beat frequency extraction.

[0073] Based on the system architecture of Figure 1 , please see Figure 3 , the embodiment of the present application provides a flowchart of a signal noise filtering method. As Figure 3 shown, the method of the embodiment of the present application can include the following steps S201-S205.

[0074] S201, acquiring an initial beat frequency signal generated by a laser radar;

[0075] Specifically, the transmitting signal of the laser radar is periodically changed according to a triangular wave, and the signal is transmitted to a detection target, and a return signal returned by the detection target is received. Since the transmitting signal and the return signal are easily affected by inherent noise of the laser radar system and the environment, the initial beat frequency signal with noise signal is presented in the frequency spectrum. The signal noise filtering device obtains the initial beat frequency signal generated by the laser radar. The initial beat frequency signal is a beat frequency signal containing noise signals.

[0076] Further, the initial beat frequency signal can be represented as x(t), the original pure beat frequency signal is s(t), and the noise signal is n(t). Therefore, x(t) = s(t) + n(t), wherein the original pure beat frequency signal can be a beat frequency signal formed in a noise-free ideal environment.

[0077] S202, performing autocorrelation processing on the initial beat frequency signal to obtain a first autocorrelation function of the initial beat frequency signal;

[0078] Specifically, for the second autocorrelation processing, the signal noise filtering device can perform autocorrelation operation processing on the initial beat frequency signal to obtain the first autocorrelation function of the initial beat frequency signal. The autocorrelation operation can be selected as an unbiased autocorrelation operation, which specifically reflects the correlation degree of the signal values at different times t1 and t2. Specifically, it can be expressed as:

[0079] R x = E[x(t1)x(t2)]

[0080] Wherein x(t1) and x(t2) represent the values of the initial beat frequency signal x(t) at t1 and t2, respectively. The first autocorrelation function R x , t1 and t2 can be randomly selected according to actual needs, or t1 and t2 can be selected according to the signal period, that is, the distance between t1 and t2 is one signal period.

[0081] S203, performing autocorrelation processing on the first autocorrelation function to obtain a useful signal corresponding to the initial beat frequency signal;

[0082] Specifically, the signal noise filtering device can perform autocorrelation processing on the first autocorrelation function again to obtain a useful signal corresponding to the initial beat frequency signal. The signal noise filtering device takes R x as x(t), and by selecting the same values at t1 and t2, autocorrelation processing is performed to obtain the useful signal corresponding to the initial beat frequency signal.

[0083] S204, determining the useful signal as a denoised time domain beat frequency signal;

[0084] Specifically, the signal noise filtering device can determine the useful signal as the de-noised time domain beat frequency signal. It can be understood that, in order to further ensure that the useful signal can be extracted, the signal noise filtering device can detect whether the target signal-to-noise ratio indicated by the useful signal is greater than a signal-to-noise threshold. The signal-to-noise threshold can be set according to actual conditions. When the target signal-to-noise ratio indicated by the useful signal is greater than the signal-to-noise threshold, the signal noise filtering device can determine the useful signal as the de-noised time domain beat frequency signal. Of course, whether the target signal-to-noise ratio detection process needs to be performed can be determined according to actual conditions. For example, for the initial beat frequency signal containing a generally strong useful signal, after the secondary autocorrelation processing, the signal-to-noise ratio can be effectively improved. At this time, the target signal-to-noise ratio detection can not be performed. For the initial beat frequency signal with a relatively weak useful signal, the secondary autocorrelation processing is still required to perform the target signal-to-noise ratio detection, so as to ensure that the target signal-to-noise ratio meets certain requirements (for example, greater than the signal-to-noise threshold), so as to facilitate subsequent extraction of the beat frequency of the useful signal.

[0085] It should be noted that the time domain beat frequency signal and the initial beat frequency signal can both represent the beat frequency signal in the time domain. The initial beat frequency signal is the beat frequency signal in the time domain before de-noising, and the time domain beat frequency signal is the beat frequency signal in the time domain after de-noising.

[0086] S205, performing Fourier transform processing on the time domain beat frequency signal to obtain a frequency domain beat frequency signal, and acquiring a beat frequency value corresponding to a maximum amplitude in the frequency domain beat frequency signal;

[0087] Specifically, the signal noise filtering device can perform Fourier transform processing on the time domain beat frequency signal to obtain a frequency domain beat frequency signal, and acquire a beat frequency value corresponding to a maximum amplitude in the frequency domain beat frequency signal. The Fourier transform processing can be fast Fourier transform processing. The frequency domain beat frequency signal can specifically represent the beat frequency signal in the frequency domain after de-noising. The signal noise filtering device can acquire the position of the maximum amplitude in the frequency spectrum formed by the frequency domain beat frequency signal, and determine the frequency value corresponding to the position as the beat frequency value of the useful signal. The useful signal specifically represents the real and effective beat frequency signal returned by the detection target from the transmitted signal.

[0088] In the embodiment of the present application, by acquiring the initial beat frequency signal containing noise signal generated by the laser radar, the initial beat frequency signal can be processed by secondary autocorrelation to obtain the useful signal of the initial beat frequency signal, and finally the useful signal is determined as the time domain beat frequency signal after noise reduction. Through the secondary autocorrelation processing, the initial beat frequency signal can be processed into an autocorrelation function based on the signal correlation degree, effectively improving the signal-to-noise ratio of the signal, extracting the weak useful signal in the initial beat frequency signal, and further improving the success rate of effective beat frequency extraction. Through the detection of the target signal-to-noise ratio, it is ensured that the target signal-to-noise ratio meets certain requirements, so as to facilitate the extraction of the beat frequency of the useful signal.

[0089] Based on the system architecture of Figure 1 , please see Figure 4 , the embodiment of the present application provides a flowchart of a signal noise filtering method. As shown in Figure 4 , the method of the embodiment of the present application can include the following steps S301-S306.

[0090] S301, acquiring the initial beat frequency signal generated by the laser radar;

[0091] Specifically, the transmission signal of the laser radar changes periodically according to the rule of the triangular wave, transmits the signal to the detection target, and receives the echo signal returned by the detection target. Since the transmission signal and the echo signal are easily affected by the inherent noise of the laser radar system, the environment and the like, the initial beat frequency signal with noise signal is presented in the frequency spectrum. The signal noise filtering device acquires the initial beat frequency signal generated by the laser radar, and the initial beat frequency signal is a beat frequency signal containing noise signal.

[0092] Further, the initial beat frequency signal can be represented as x(t), the original pure beat frequency signal is s(t), and the noise signal is n(t), so x(t) = s(t) + n(t), wherein the original pure beat frequency signal can be the beat frequency signal formed by the beat frequency signal in the ideal environment without noise.

[0093] S302, autocorrelation processing the initial beat frequency signal to obtain the second autocorrelation function of the initial beat frequency signal;

[0094] Specifically, the signal noise filtering device performs autocorrelation processing on the initial beat frequency signal to obtain the second autocorrelation function of the initial beat frequency signal. The autocorrelation operation can be selected as an unbiased autocorrelation operation, which specifically reflects the correlation degree of the signal values at different times t1 and t2, and can be expressed as:

[0095] R x = E[x(t1)x(t2)]

[0096] Wherein, x(t1) and x(t2) represent the values of t1 and t2 in the initial difference frequency signal x(t) respectively, and the second autocorrelation function R x , t1 and t2 can be randomly selected according to actual needs, or t1 and t2 can be selected according to the signal period, that is, the distance between t1 and t2 is one signal period.

[0097] S303, when the first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to the signal-to-noise threshold, the second autocorrelation function is determined as the initial difference frequency signal;

[0098] Specifically, when the first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to the signal-to-noise threshold, the signal noise filtering device can determine the second autocorrelation function as the initial difference frequency signal, and turn to execute step S302. When the first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to the signal-to-noise threshold, the signal noise filtering device can determine R x As x(t), the same t1 and t2 values are selected for autocorrelation processing, and the second autocorrelation function is obtained again. This process is repeated until the first signal-to-noise ratio greater than the signal-to-noise threshold is detected, and step S304 is executed.

[0099] S304, when the first signal-to-noise ratio is greater than the signal-to-noise threshold, the second autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal;

[0100] Specifically, when the first signal-to-noise ratio is greater than the signal-to-noise threshold, the signal noise filtering device can determine the second autocorrelation function as the useful signal corresponding to the initial difference frequency signal, that is, the signal noise filtering device can determine the last obtained R x As the useful signal corresponding to the initial difference frequency signal.

[0101] S305, the useful signal is determined as the denoised time domain difference frequency signal;

[0102] Specifically, the signal noise filtering device can determine the useful signal as the de-noised time domain beat frequency signal. It can be understood that, in order to further ensure that the useful signal can be extracted, the signal noise filtering device can detect whether the target signal-to-noise ratio indicated by the useful signal is greater than a signal-to-noise threshold. The signal-to-noise threshold can be set according to actual conditions. When the target signal-to-noise ratio indicated by the useful signal is greater than the signal-to-noise threshold, the signal noise filtering device can determine the useful signal as the de-noised time domain beat frequency signal. Of course, whether the target signal-to-noise ratio detection process needs to be performed can be determined according to actual conditions. For example, for the initial beat frequency signal containing a generally strong useful signal, after the secondary autocorrelation processing, the signal-to-noise ratio can be effectively improved. At this time, the target signal-to-noise ratio detection can not be performed. For the initial beat frequency signal with a relatively weak useful signal, whether the secondary autocorrelation processing or the at least one autocorrelation processing convergence mode needs to be performed. The target signal-to-noise ratio detection needs to be performed to ensure that the target signal-to-noise ratio meets certain requirements (for example, greater than the signal-to-noise threshold) so as to facilitate the extraction of the beat frequency of the useful signal in the subsequent process. The process of the secondary autocorrelation processing can be referred to in the specific description of the embodiment shown in Figure 3 The specific description of the embodiment shown in the foregoing is not repeated here.

[0103] It should be noted that the time domain beat frequency signal and the initial beat frequency signal can both represent the beat frequency signal in the time domain. The initial beat frequency signal is the beat frequency signal in the time domain before de-noising, and the time domain beat frequency signal is the beat frequency signal in the time domain after de-noising.

[0104] S306, performing Fourier transform processing on the time domain beat frequency signal to obtain a frequency domain beat frequency signal, and acquiring a beat frequency value corresponding to a maximum amplitude in the frequency domain beat frequency signal;

[0105] Specifically, the signal noise filtering device can perform Fourier transform processing on the time domain beat frequency signal to obtain a frequency domain beat frequency signal, and acquire a beat frequency value corresponding to a maximum amplitude in the frequency domain beat frequency signal. The Fourier transform processing can be fast Fourier transform processing. The frequency domain beat frequency signal can specifically represent the beat frequency signal in the frequency domain after de-noising. The signal noise filtering device can acquire the position of the maximum amplitude in the frequency spectrum formed by the frequency domain beat frequency signal, and determine the frequency value corresponding to the position as the beat frequency value of the useful signal. The useful signal specifically represents the real and effective beat frequency signal returned by the detection target.

[0106] In the embodiment of the present application, by acquiring the initial beat frequency signal containing noise signal generated by the laser radar, at least one autocorrelation processing can be performed on the initial beat frequency signal to obtain the useful signal of the initial beat frequency signal, and finally the useful signal is determined as the time domain beat frequency signal after noise reduction. Through at least one autocorrelation processing, the initial beat frequency signal can be processed into an autocorrelation function based on the correlation degree of the signal, effectively improving the signal-to-noise ratio of the signal, extracting the weak useful signal in the initial beat frequency signal, and further improving the success rate of effective beat frequency extraction.

[0107] Based on Figure 1 the system architecture, please see Figure 5 , the embodiment of the present application provides a flowchart of a signal noise filtering method. As Figure 5 shown, the method of the embodiment of the present application can include the following steps S401-S407.

[0108] S401, acquiring the initial beat frequency signal generated by the laser radar;

[0109] Specifically, the transmission signal of the laser radar periodically changes according to the law of the triangular wave, performs signal transmission on the detection target, and receives the echo signal returned by the detection target. Since the transmission signal and the echo signal are easily affected by inherent noise such as laser radar system and environment, the initial beat frequency signal with noise signal is presented in the frequency spectrum. The signal noise filtering device acquires the initial beat frequency signal generated by the laser radar, and the initial beat frequency signal is a beat frequency signal containing noise signal.

[0110] Further, the initial beat frequency signal can be represented as x(t), the original pure beat frequency signal is s(t), and the noise signal is n(t), so x(t) = s(t) + n(t), wherein the original pure beat frequency signal can be the beat frequency signal formed by the beat frequency signal in the ideal environment without noise.

[0111] S402, autocorrelation processing is performed on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and the number of processing times of the autocorrelation processing is updated;

[0112] Specifically, the signal noise filtering device performs autocorrelation processing on the initial beat frequency signal to obtain a second autocorrelation function of the initial beat frequency signal. The autocorrelation operation can be selected as an unbiased autocorrelation operation, which specifically reflects the correlation degree of the signal at different times t1 and t2, and can be expressed as:

[0113] R x =E[x(t1)x(t2)]

[0114] wherein x(t1) and x(t2) represent the values of the initial difference frequency signal x(t) at t1 and t2 respectively, and the second autocorrelation function R x t1 and t2 can be randomly selected according to actual requirements, or t1 and t2 can be selected according to a signal period, i.e., the distance between t1 and t2 is one signal period.

[0115] The signal noise filtering device can also record the number of autocorrelation processing times. It can be understood that the number of processing times can be updated after one autocorrelation processing, for example, the initial number of processing times is 0, the number of processing times is increased by 1 after one autocorrelation processing, and so on.

[0116] S403, when the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing times is less than the number threshold, the third autocorrelation function is determined as the initial difference frequency signal, and the step of performing autocorrelation processing on the initial difference frequency signal to obtain the second autocorrelation function of the initial difference frequency signal is executed, and the number of autocorrelation processing times is updated;

[0117] Specifically, when the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing times is less than the number threshold, the signal noise filtering device can determine the third autocorrelation function as the initial difference frequency signal, and execute step S402. When the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing times is less than the number threshold, the signal noise filtering device can determine R x As x(t), the same values at t1 and t2 are selected, autocorrelation processing is performed again, the third autocorrelation function is obtained again, the number of processing times is increased by 1, and the process is repeated until at least one of the two convergence conditions is detected, and step S404 or step S405 is executed.

[0118] Optionally, one convergence condition is that a second signal-to-noise ratio indicated by the third autocorrelation function satisfies a signal-to-noise threshold, and another convergence condition is that the number of processing times of the autocorrelation processing is limited within a number threshold, and the signal-to-noise threshold and the number threshold can be set according to actual needs. By setting the signal-to-noise threshold, the signal-to-noise ratio of the initial difference frequency signal can be effectively improved after the autocorrelation processing, and then the success rate of extracting the useful signal in the initial difference frequency signal is improved. By setting the number threshold, although the signal-to-noise ratio of the initial difference frequency signal still cannot reach the signal-to-noise threshold after the autocorrelation processing of the initial difference frequency signal for a preset number of times, the useful signal can be extracted from the initial difference frequency signal at this time. Therefore, by limiting the number of processing times of the autocorrelation processing through the number threshold, the extraction efficiency of the difference frequency of the useful signal can be ensured.

[0119] S404, when the second signal-to-noise ratio indicated by the third autocorrelation function is greater than the signal-to-noise threshold, and the number of processing times is less than the number threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal.

[0120] Specifically, when the second signal-to-noise ratio is greater than the signal-to-noise threshold, and the number of processing times is less than the number threshold, the signal noise filtering device can determine the third autocorrelation function as the useful signal corresponding to the initial difference frequency signal, that is, the signal noise filtering device can determine the R x determined as the useful signal corresponding to the initial difference frequency signal.

[0121] S405, when the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing times is equal to the number threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal.

[0122] Specifically, when the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing times is equal to the number threshold, the signal noise filtering device can determine the third autocorrelation function as the useful signal corresponding to the initial difference frequency signal, that is, the signal noise filtering device can determine the R x determined as the useful signal corresponding to the initial difference frequency signal.

[0123] In the embodiments of the present application, steps S404 and S405 respectively represent that when any one of the two convergence conditions is met, the R x determined as the useful signal corresponding to the initial difference frequency signal; of course, the present application also exists when the second signal-to-noise ratio indicated by the third autocorrelation function is greater than the signal-to-noise threshold, and the number of processing times is equal to the number threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal.

[0124] S406, determine the useful signal as the de-noised time domain beat signal;

[0125] Specifically, the signal noise filtering device can determine the useful signal as the de-noised time domain beat signal. It can be understood that for the initial beat signal with weak useful signal, the number of autocorrelation processing can be detected while detecting the target signal-to-noise ratio, so as to limit the number of processing within a certain range (for example, equal to the number threshold) when the target signal-to-noise ratio still cannot meet certain requirements, so as to ensure the processing efficiency of extracting the beat frequency of the useful signal.

[0126] It should be noted that the time domain beat signal and the initial beat signal can both represent the beat signal in the time domain. The initial beat signal is the beat signal in the time domain before de-noising, and the time domain beat signal is the beat signal in the time domain after de-noising.

[0127] S407, performing Fourier transform processing on the time domain beat signal to obtain a frequency domain beat signal, and obtaining a beat frequency value corresponding to the maximum amplitude in the frequency domain beat signal;

[0128] Specifically, the signal noise filtering device can perform Fourier transform processing on the time domain beat signal to obtain a frequency domain beat signal, and obtain a beat frequency value corresponding to the maximum amplitude in the frequency domain beat signal. The Fourier transform processing can be fast Fourier transform processing. The frequency domain beat signal can specifically represent the beat signal in the frequency domain after de-noising. The signal noise filtering device can obtain the position of the maximum amplitude in the frequency spectrum formed by the frequency domain beat signal, and determine the frequency value corresponding to the position as the beat frequency value of the useful signal. The useful signal specifically represents the real and effective beat signal returned by the detection target after the transmission signal.

[0129] In the embodiments of the present application, by obtaining the initial beat signal containing noise signal generated by the laser radar, at least one autocorrelation processing can be performed on the initial beat signal to obtain the useful signal of the initial beat signal, and finally the useful signal is determined as the de-noised time domain beat signal. Through at least one autocorrelation processing, the initial beat signal can be processed into an autocorrelation function based on the correlation degree of the signal, which effectively improves the signal-to-noise ratio of the signal, extracts the weak useful signal in the initial beat signal, and further improves the success rate of extracting the beat frequency of the useful signal. By detecting the target signal-to-noise ratio, it is ensured that the target signal-to-noise ratio meets certain requirements, so as to facilitate the extraction of the beat frequency of the useful signal. By limiting the number of autocorrelation processing, the extraction efficiency of the beat frequency of the useful signal can be improved on the basis of improving the extraction success rate of the useful signal in the initial beat signal.

[0130] Please refer toFigure 6 This provides an example schematic diagram of the spectrum of a signal after Fourier transform, which is provided for the embodiments of this application. Figure 6 The spectrum diagrams of three signals are shown. The three signals are the original pure signal (i.e., the original pure difference frequency signal), the signal obtained by processing the initial difference frequency signal through Fast Fourier Transform (FFT), and the signal obtained by processing the initial difference frequency signal through autocorrelation and FFT.

[0131] Depend on Figure 6 It can be seen that the difference frequency of the useful signal of the original pure signal as the standard signal is (4×10). 8 )Hz; while the signal obtained solely through FFT processing has a difference frequency corresponding to its maximum amplitude located at )Hz; Figure 6 As indicated by the "black arrow," it is clear that FFT processing alone is insufficient to accurately obtain the difference frequency of the useful signal. The difference frequency of the signal obtained after autocorrelation and FFT processing is consistent with the original transmitted signal. Therefore, by performing autocorrelation processing on the initial difference frequency signal, noise signals in the initial difference frequency signal can be effectively filtered out, thereby improving the success rate of effective difference frequency extraction.

[0132] Please see Figure 7 This illustration provides an example of the success rate of extracting useful signals under different signal-to-noise ratios in embodiments of this application. Figure 7 As shown, the solid line represents the detection success rate of extracting the difference frequency of the target from the initial difference frequency signal after only FFT processing; the dashed line represents the detection success rate of extracting the difference frequency of the target from the initial difference frequency signal after autocorrelation processing and FFT processing.

[0133] In a scenario of 1000 processing iterations at different signal-to-noise ratios, it is clear that after autocorrelation processing, the initial difference frequency signal can more effectively filter out noise signals at different signal-to-noise ratios, thereby obtaining the useful signal of the target and acquiring the difference frequency of the useful signal.

[0134] Please see Figure 8 This illustration provides examples of the number of successful extractions of useful signals under different detection distances and signal-to-noise ratios in embodiments of this application. Figure 8 As shown, the solid line represents the detection success rate of extracting the difference frequency of the target from the initial difference frequency signal after only FFT processing; the dashed line represents the detection success rate of extracting the difference frequency of the target from the initial difference frequency signal after autocorrelation processing and FFT processing.

[0135] In the 1000 processing scenarios of different target distances of different detection targets and different SNRs, the initial difference frequency signal can be filtered more effectively from the noise signal after the autocorrelation processing under different SNRs, so as to obtain the useful signal of the detection target and obtain the difference frequency of the useful signal, and the target distance of the detection target does not affect the extraction of the useful signal.

[0136] Based on the system architecture of Figure 1 , the signal noise filtering device provided by the embodiment of the present application will be described in detail below. It should be noted that the signal noise filtering device in the Figure 9 -attached Figure 13 , the signal noise filtering device provided by the embodiment of the present application will be described in detail below. It should be noted that the signal noise filtering device in the Figure 9 -attached Figure 13 , the signal noise filtering device provided by the embodiment of the present application will be described in detail below. It should be noted that the signal noise filtering device in the Figures 2-8 , the signal noise filtering device provided by the embodiment of the present application will be described in detail below. It should be noted that the signal noise filtering device in the Figures 2-8 , the signal noise filtering device provided by the embodiment of the present application will be described in detail below. It should be noted that the signal noise filtering device in the

[0137] Please refer to Figure 9 , a structural schematic diagram of a signal noise filtering device provided by the embodiment of the present application. As shown in Figure 9 , the signal noise filtering device 1 provided by the embodiment of the present application can include an initial signal acquisition unit 11, a signal processing unit 12 and a de-noising signal determination unit 13.

[0138] The initial signal acquisition unit 11 is configured to acquire an initial difference frequency signal generated by a laser radar, wherein the initial difference frequency signal is a difference frequency signal containing noise signals.

[0139] The signal processing unit 12 is configured to perform autocorrelation processing on the initial difference frequency signal at least once to obtain a useful signal of the initial difference frequency signal.

[0140] The de-noising signal determination unit 13 is configured to determine the useful signal as a de-noised time domain difference frequency signal.

[0141] In the embodiment of the present application, by acquiring the initial difference frequency signal containing noise signals generated by the laser radar, at least one autocorrelation processing can be performed on the initial difference frequency signal to obtain the useful signal of the initial difference frequency signal, and finally the useful signal is determined as the de-noised time domain difference frequency signal. Through at least one autocorrelation processing, the initial difference frequency signal can be processed into an autocorrelation function based on the signal correlation degree, the signal-to-noise ratio of the signal is effectively improved, the weak useful signal in the initial difference frequency signal is extracted, and the success rate of the effective difference frequency extraction is improved.

[0142] Please refer to Figure 10 , a structural schematic diagram of a signal noise filtering device provided by the embodiment of the present application. As shown in Figure 10As shown, the signal noise filtering device 1 of the embodiment of the present application can comprise: an initial signal acquisition unit 11, a signal processing unit 12, a de-noised signal determination unit 13 and a difference frequency acquisition unit 14.

[0143] The initial signal acquisition unit 11 is configured to acquire an initial difference frequency signal generated by the laser radar, wherein the initial difference frequency signal is a difference frequency signal containing noise signals.

[0144] The signal processing unit 12 is configured to perform at least one autocorrelation processing on the initial difference frequency signal to obtain a useful signal of the initial difference frequency signal.

[0145] Specifically, in the first feasible implementation manner of the present application, please refer to Figure 11 A structural schematic diagram of the signal processing unit is provided for the embodiment of the present application. As shown in the figure, Figure 11 The signal processing unit 12 can comprise:

[0146] The first signal processing sub-unit 121 is configured to perform autocorrelation processing on the initial difference frequency signal to obtain a first autocorrelation function of the initial difference frequency signal.

[0147] The function processing sub-unit 122 is configured to perform autocorrelation processing on the first autocorrelation function to obtain a useful signal corresponding to the initial difference frequency signal.

[0148] In the second feasible implementation manner of the present application, please refer to Figure 12 A structural schematic diagram of the signal processing unit is provided for the embodiment of the present application. As shown in the figure, Figure 12 The signal processing unit 12 can comprise:

[0149] The second signal processing sub-unit 123 is configured to perform autocorrelation processing on the initial difference frequency signal to obtain a second autocorrelation function of the initial difference frequency signal.

[0150] The first notification sub-unit 124 is configured to determine the second autocorrelation function as the initial difference frequency signal when a first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to a signal-to-noise threshold, and notify the second signal processing sub-unit 123 to perform autocorrelation processing on the initial difference frequency signal to obtain a second autocorrelation function of the initial difference frequency signal until the first signal-to-noise ratio is greater than the signal-to-noise threshold, and then determine the second autocorrelation function as a useful signal corresponding to the initial difference frequency signal.

[0151] In the third feasible implementation manner of the present application, please refer to Figure 13 A structural schematic diagram of the signal processing unit is provided for the embodiment of the present application. As shown in the figure, Figure 13 The signal processing unit 12 can comprise:

[0152] The third signal processing subunit 125 is configured to perform autocorrelation processing on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and update the number of times of the autocorrelation processing;

[0153] The second notification subunit 126 is configured to determine the third autocorrelation function as the initial beat frequency signal when a second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to a signal-to-noise threshold value and the number of times is less than a number-of-times threshold value, and notify the third signal processing subunit 125 to perform autocorrelation processing on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and update the number of times of the autocorrelation processing;

[0154] The signal determination subunit 127 is configured to determine the third autocorrelation function as a useful signal corresponding to the initial beat frequency signal when a second signal-to-noise ratio indicated by the third autocorrelation function is greater than a signal-to-noise threshold value and the number of times is less than a number-of-times threshold value.

[0155] The signal determination subunit 127 is further configured to determine the third autocorrelation function as a useful signal corresponding to the initial beat frequency signal when a second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to a signal-to-noise threshold value and the number of times is equal to a number-of-times threshold value.

[0156] The de-noising signal determination unit 13 is configured to determine the useful signal as a de-noised time-domain beat frequency signal.

[0157] In specific implementation, the de-noising signal determination unit 13 is specifically configured to determine the useful signal as a de-noised time-domain beat frequency signal when a target signal-to-noise ratio indicated by the useful signal is greater than a signal-to-noise threshold value.

[0158] The beat frequency acquisition unit 14 is configured to perform Fourier transform processing on the time-domain beat frequency signal to obtain a frequency-domain beat frequency signal, and acquire a beat frequency value corresponding to a maximum amplitude in the frequency-domain beat frequency signal.

[0159] In the embodiments of the present application, by acquiring an initial beat frequency signal containing a noise signal generated by a laser radar, at least one autocorrelation processing can be performed on the initial beat frequency signal to obtain a useful signal of the initial beat frequency signal, and finally the useful signal is determined as a de-noised time-domain beat frequency signal. Through at least one autocorrelation processing, the initial beat frequency signal can be processed into an autocorrelation function based on the correlation degree of the signal, effectively improving the signal-to-noise ratio of the signal, extracting the weak useful signal in the initial beat frequency signal, and further improving the success rate of extracting the beat frequency of the useful signal. Through detection of the target signal-to-noise ratio, it is ensured that the target signal-to-noise ratio meets certain requirements, so as to facilitate subsequent extraction of the beat frequency of the useful signal.

[0160] This application also provides a computer storage medium that can store multiple program instructions, which are adapted to be loaded and executed by a processor as described above. Figures 2-4 The method steps of the illustrated embodiment can be found in the following documentation for detailed execution. Figures 2-4 The specific details of the illustrated embodiments will not be elaborated here.

[0161] Please see Figure 14 The diagram below provides a structural schematic of a lidar according to an embodiment of this application. Figure 14 As shown, the lidar 1000 may include: at least one processor 1001, such as a CPU; at least one network interface 1004; an input / output interface 1003; a memory 1005; and at least one communication bus 1002. The communication bus 1002 is used to enable communication between these components. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be high-speed RAM or non-volatile memory, such as at least one disk storage device. Optionally, the memory 1005 may also be at least one storage device located remotely from the aforementioned processor 1001. Figure 14 As shown, the memory 1005, which serves as a computer storage medium, may include an operating system, a network communication module, an input / output interface module, and a noise filtering application.

[0162] exist Figure 14 In the lidar 1000 shown, the input / output interface 1003 is mainly used to provide an input interface for users and access devices to acquire data input by users and access devices.

[0163] In one embodiment, processor 1001 can be used to invoke a noise filtering application stored in memory 1005 and specifically perform the following operations:

[0164] Acquire the initial difference frequency signal generated by the lidar, wherein the initial difference frequency signal is a difference frequency signal containing noise;

[0165] The initial difference frequency signal is subjected to at least one autocorrelation processing to obtain the useful signal of the initial difference frequency signal;

[0166] The useful signal is determined as the denoised time-domain difference frequency signal.

[0167] Optionally, when the processor 1001 performs at least one autocorrelation processing on the initial difference frequency signal to obtain a useful signal of the initial difference frequency signal, it specifically performs the following operations:

[0168] performing autocorrelation processing on the initial beat frequency signal to obtain a first autocorrelation function of the initial beat frequency signal;

[0169] performing autocorrelation processing on the first autocorrelation function to obtain a useful signal corresponding to the initial beat frequency signal.

[0170] Optionally, when performing the autocorrelation processing on the initial beat frequency signal at least once to obtain the autocorrelation function of the initial beat frequency signal, the processor 1001 specifically performs the following operations:

[0171] performing autocorrelation processing on the initial beat frequency signal to obtain a second autocorrelation function of the initial beat frequency signal;

[0172] When a first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to a signal-to-noise threshold, the second autocorrelation function is determined as the initial beat frequency signal, and the step of performing autocorrelation processing on the initial beat frequency signal to obtain a second autocorrelation function of the initial beat frequency signal is performed until the first signal-to-noise ratio is greater than the signal-to-noise threshold, and the second autocorrelation function is determined as a useful signal corresponding to the initial beat frequency signal.

[0173] Optionally, when performing the autocorrelation processing on the initial beat frequency signal at least once to obtain the useful signal of the initial beat frequency signal, the processor 1001 specifically performs the following operations:

[0174] performing autocorrelation processing on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and updating a processing number of the autocorrelation processing;

[0175] When a second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to a signal-to-noise threshold, and the processing number is less than a number threshold, the third autocorrelation function is determined as the initial beat frequency signal, and the step of performing autocorrelation processing on the initial beat frequency signal to obtain a third autocorrelation function of the initial beat frequency signal, and updating a processing number of the autocorrelation processing is performed;

[0176] When the second signal-to-noise ratio indicated by the third autocorrelation function is greater than the signal-to-noise threshold, and the processing number is less than the number threshold, the third autocorrelation function is determined as a useful signal corresponding to the initial beat frequency signal.

[0177] When the second signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the processing number is equal to the number threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial beat frequency signal.

[0178] Optionally, the processor 1001 specifically performs the following operation when determining the useful signal as the de-noised time-domain beat signal:

[0179] When the target signal-to-noise ratio indicated by the useful signal is greater than a signal-to-noise threshold, the useful signal is determined as the de-noised time-domain beat signal.

[0180] Optionally, the processor 1001 further performs the following operation:

[0181] The time-domain beat signal is subjected to Fourier transform processing to obtain a frequency-domain beat signal, and a beat frequency value corresponding to a maximum amplitude in the frequency-domain beat signal is acquired.

[0182] In the embodiments of the present application, the initial beat signal containing noise signals generated by the laser radar can be subjected to at least one autocorrelation processing to obtain a useful signal of the initial beat signal, and finally the useful signal is determined as the de-noised time-domain beat signal. Through at least one autocorrelation processing, the initial beat signal can be processed into an autocorrelation function based on the signal correlation degree, effectively improving the signal-to-noise ratio of the signal, extracting the weak useful signal in the initial beat signal, and further improving the success rate of extracting the effective beat frequency. Through detection of the target signal-to-noise ratio, it is ensured that the target signal-to-noise ratio meets certain requirements, so as to facilitate subsequent extraction of the beat frequency of the useful signal.

[0183] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above-mentioned embodiments. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM) or a random access memory (RAM), etc.

[0184] The above only describes the preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so equivalent changes made according to the claims of the present application still fall within the scope of the present application.

Claims

1. A method for signal noise filtering, characterized in that, include: Acquire the initial difference frequency signal generated by the lidar, wherein the initial difference frequency signal is a difference frequency signal containing noise; The initial difference frequency signal is subjected to at least one autocorrelation processing to obtain the useful signal of the initial difference frequency signal; The useful signal is determined as the denoised time-domain difference frequency signal; Wherein, performing at least one autocorrelation processing on the initial difference frequency signal to obtain the useful signal of the initial difference frequency signal includes: The initial difference frequency signal is subjected to autocorrelation processing to obtain the third autocorrelation function of the initial difference frequency signal. The number of autocorrelation processing steps is then updated. The expression for the third autocorrelation function is: R x =E[x(t1)x(t2)], where x(t1) and x(t2) represent the values ​​of the initial difference frequency signal x(t) at times t1 and t2, respectively, and R x The third autocorrelation function; When the first signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing steps is less than the number of processing steps threshold, the third autocorrelation function is determined as the initial difference frequency signal, and the process proceeds to perform autocorrelation processing on the initial difference frequency signal to obtain the third autocorrelation function of the initial difference frequency signal, and the number of processing steps of the autocorrelation processing is updated. When the first signal-to-noise ratio indicated by the third autocorrelation function is greater than the signal-to-noise threshold, and the number of processing steps is less than the number of processing steps threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal. When the first signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing steps is equal to the number of processing steps threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal.

2. The method according to claim 1, characterized in that, The step of performing at least one autocorrelation processing on the initial difference frequency signal to obtain a useful signal from the initial difference frequency signal includes: The initial difference frequency signal is subjected to autocorrelation processing to obtain the first autocorrelation function of the initial difference frequency signal; The first autocorrelation function is subjected to autocorrelation processing to obtain the useful signal corresponding to the initial difference frequency signal.

3. The method according to claim 1, characterized in that, The step of performing at least one autocorrelation processing on the initial difference frequency signal to obtain a useful signal from the initial difference frequency signal includes: The initial difference frequency signal is subjected to autocorrelation processing to obtain the second autocorrelation function of the initial difference frequency signal; When the first signal-to-noise ratio indicated by the second autocorrelation function is less than or equal to the signal-to-noise threshold, the second autocorrelation function is determined as the initial difference frequency signal, and the process proceeds to perform autocorrelation processing on the initial difference frequency signal to obtain the second autocorrelation function of the initial difference frequency signal, until the first signal-to-noise ratio is greater than the signal-to-noise threshold, and the second autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal.

4. The method according to claim 1 or 3, characterized in that, Determining the useful signal as a denoised time-domain difference frequency signal includes: When the target signal-to-noise ratio indicated by the useful signal is greater than the signal-to-noise threshold, the useful signal is determined as the denoised time-domain difference frequency signal.

5. The method according to claim 1, characterized in that, Also includes: The time-domain difference frequency signal is subjected to Fourier transform processing to obtain the frequency-domain difference frequency signal, and the difference frequency value corresponding to the maximum amplitude value is obtained from the frequency-domain difference frequency signal.

6. A signal noise filtering device, characterized in that, include: An initial signal acquisition unit is used to acquire the initial difference frequency signal generated by the lidar, wherein the initial difference frequency signal is a difference frequency signal containing noise. A signal processing unit is configured to perform at least one autocorrelation processing on the initial difference frequency signal to obtain a useful signal of the initial difference frequency signal; A denoised signal determination unit is used to determine the useful signal as a denoised time-domain difference frequency signal; Specifically, the signal processing unit is used for: The initial difference frequency signal is subjected to autocorrelation processing to obtain the third autocorrelation function of the initial difference frequency signal. The number of autocorrelation processing steps is then updated. The expression for the third autocorrelation function is: R x =E[x(t1)x(t2)], where x(t1) and x(t2) represent the values ​​of the initial difference frequency signal x(t) at times t1 and t2, respectively, and R x The third autocorrelation function; When the first signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing steps is less than the number of processing steps threshold, the third autocorrelation function is determined as the initial difference frequency signal, and the process proceeds to perform autocorrelation processing on the initial difference frequency signal to obtain the third autocorrelation function of the initial difference frequency signal, and the number of processing steps of the autocorrelation processing is updated. When the first signal-to-noise ratio indicated by the third autocorrelation function is greater than the signal-to-noise threshold, and the number of processing steps is less than the number of processing steps threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal. When the first signal-to-noise ratio indicated by the third autocorrelation function is less than or equal to the signal-to-noise threshold, and the number of processing steps is equal to the number of processing steps threshold, the third autocorrelation function is determined as the useful signal corresponding to the initial difference frequency signal.

7. The apparatus according to claim 6, characterized in that, The signal processing unit includes: The first signal processing subunit is used to perform autocorrelation processing on the initial difference frequency signal to obtain the first autocorrelation function of the initial difference frequency signal; The function processing subunit is used to perform autocorrelation processing on the first autocorrelation function to obtain the useful signal corresponding to the initial difference frequency signal.

8. A lidar, characterized in that, Includes processor, memory, and input / output interfaces; The processor is connected to the memory and the input / output interface respectively, wherein the input / output interface is used for page interaction, the memory is used to store program code, and the processor is used to call the program code to execute the method as described in any one of claims 1-5.

9. A computer storage medium, characterized in that, The computer storage medium stores a computer program, the computer program including program instructions, which, when executed by a processor, perform the method as described in any one of claims 1-5.

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