Method, apparatus and device for echo delay determination of chirp acoustic signals

Abstract

The embodiment of the application provides a method, device and equipment for determining echo delay of a linear frequency modulation acoustic signal. The method is applied to the field of digital signal processing. Time-varying band-pass filtering is performed on an acquired acoustic signal, the filtered acoustic signal is subjected to short-time Fourier transform and logarithm is taken, and a logarithmic time-frequency spectrum is obtained. Peak information in the logarithmic time-frequency spectrum is extracted, and a frequency modulation line of a linear frequency modulation signal is fitted, and an initial frequency of the linear frequency modulation signal is obtained. The frequency modulation line of the linear frequency modulation signal and the peak information in the logarithmic time-frequency spectrum are used for signal reconstruction, the reconstructed signal is subjected to short-time Fourier transform and logarithm is taken, a reconstructed spectrum is obtained, and a difference spectrum is obtained by subtracting the reconstructed spectrum from the logarithmic time-frequency spectrum. Peak information of the difference spectrum is extracted, a frequency modulation line of an echo signal is fitted, and an initial frequency of the echo signal is obtained. The initial frequency difference between the linear frequency modulation signal and the echo signal is used to determine an echo delay amount. The method has strong anti-interference capability and improves the calculation precision of the echo delay amount.

Description

Technical Field

[0001] This application relates to the field of digital signal processing, and in particular to a method, apparatus and device for determining the echo delay of a linear frequency modulated (FM) acoustic signal. Background Technology

[0002] The pulse-echo method, due to its simple principle and convenient operation, is widely used in scenarios such as oil well dynamic fluid level detection, pipeline leak and blockage location, and tubing length measurement. In oil well dynamic fluid level detection, a high-energy acoustic pulse is emitted into the well casing. The sound wave propagates in the air of the casing annulus and is reflected upon encountering the fluid surface. By measuring the time interval between the acoustic pulse and the reflected echo, and combining this with the sound velocity inside the wellbore, the depth of the dynamic fluid level can be calculated. Leaks and blockages in pipelines can be considered as abrupt changes in acoustic impedance within the pipe. Sound waves are emitted into the pipe, and as they propagate along the pipe, they are reflected at the points of impedance change, forming echoes. By analyzing the time delay between the reflected and incident waves and the sound wave propagation velocity, the location of leaks and blockages can be determined. Measuring the length of buried pipelines and blind tunnels in mountains is challenging due to the confined space and complex environment, making it difficult to install traditional measuring tools. The pulse-echo method, however, only requires a sound-emitting device to be used at the port to emit sound waves. The sound waves are reflected at the distant interface, and by identifying the arrival time of the echo, the total length of the pipeline structure can be calculated using the speed of sound. In the aforementioned measurement scenarios, by emitting high-energy pulsed sound waves such as infrasound pulses, low-frequency pulses, and ultrasonic pulses towards the target, and measuring the delay of the echo signal, target detection can be achieved based on the mathematical relationship between the distance to be measured and the echo delay.

[0003] The echo delay is a key parameter for successfully measuring target distance using the pulse-echo method, and its calculation accuracy directly determines the precision of the measurement results. In short-to-medium distance detection, echo signal identification is relatively easy, and with accurate echo delay estimation, the pulse-echo method can achieve high-precision results for target distance measurement. Furthermore, by converting the distance measurement of the target into the calculation of the acoustic echo delay, the pulse-echo method can overcome the limitations of direct distance measurement in practical applications, enabling effective detection of difficult-to-reach targets or in confined environments. However, at excessively long detection distances, the pulsed acoustic wave attenuates rapidly during propagation, especially in pipelines with many bends. The acoustic echo generated by long-distance measurement is very weak and easily submerged in environmental noise, leading to misjudgments and omissions of the true echo. Simultaneously, clutter reflected from pipe bends, valves, etc., may also appear in the echo, overlapping with the target echo signal and severely interfering with the accurate identification of obstacle echoes, ultimately affecting the calculation accuracy of the pulse-echo delay. Summary of the Invention

[0004] This application provides a method, apparatus, and device for determining the echo delay of a linear frequency modulated (FM) audio signal, in order to solve the problem in the prior art that the echo signal is easily interfered with, resulting in low accuracy in the calculation of the echo delay.

[0005] In a first aspect, this application provides a method for determining the echo delay of a linear frequency modulated (FM) audio signal, the method comprising:

[0006] The acquired acoustic signal is subjected to time-varying bandpass filtering to obtain the time-varying bandpass filtered acoustic signal;

[0007] A short-time Fourier transform is performed on the time-varying bandpass filtered acoustic signal to obtain the time spectrum of the signal, and the logarithm of the time spectrum is taken to obtain the logarithmic time spectrum.

[0008] Determine the peak information in the logarithmic time spectrum, fit the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determine the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal.

[0009] The signal is reconstructed using the frequency modulation line and peak information in the logarithmic time spectrum of the linear frequency modulated signal to obtain the reconstructed linear frequency modulated signal;

[0010] The reconstructed spectrum is obtained by taking the logarithm of the short-time Fourier transform of the linear frequency modulated reconstructed signal. The difference between the reconstructed spectrum and the logarithmic spectrum is obtained as the difference spectrum.

[0011] Determine the peak information in the spectrum after subtraction, fit the echo signal frequency modulation line based on the peak information in the spectrum after subtraction, and determine the initial frequency of the echo signal based on the echo signal frequency modulation line.

[0012] Determine the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, and then determine the echo delay based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal.

[0013] Optionally, the step of performing time-varying bandpass filtering on the acquired acoustic signal to obtain a time-varying bandpass filtered acoustic signal includes:

[0014] Acquire the first linear frequency modulated signal generated by the signal generator, construct a second linear frequency modulated signal with reversed slope based on the slope of the first linear frequency modulated signal, and multiply the second linear frequency modulated signal with the acquired acoustic signal to obtain the multiplication result;

[0015] The multiplication result is filtered using a bandpass filter to obtain the bandpass-filtered signal;

[0016] The complex conjugate signal of the second linear frequency modulated signal is multiplied by the bandpass filtered signal to obtain the time-varying bandpass filtered acoustic signal.

[0017] Optionally, the step of performing a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the signal time spectrum includes:

[0018] A Gaussian window is used as the analysis window to divide the time-varying bandpass filtered acoustic signal into frames, resulting in multi-frame sub-signals.

[0019] The sub-signal spectrum is obtained by fast Fourier transform of each frame sub-signal, and the sub-signal spectra are combined into a complete signal time spectrum according to the frame order.

[0020] Optionally, determining the peak information in the logarithmic spectrum includes:

[0021] Extract the maximum peak value of each sub-signal spectrum in the logarithmic time spectrum, and record the amplitude and corresponding frequency of each maximum peak value;

[0022] The amplitude and corresponding frequency of each maximum peak are arranged in the order of the sub-signals to form the amplitude sequence and frequency sequence of the maximum peak.

[0023] Optionally, the step of fitting the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determining the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal, includes:

[0024] Based on the frequency sequence and time sequence of the maximum peak value, the frequency modulation line of the linear frequency modulation signal is obtained by least squares fitting.

[0025] The frequency modulation line of the linear frequency modulation signal satisfies the following formula:

[0026]

[0027] in, This represents the frequency modulation line for a linear frequency modulation signal. The initial frequency value of the linear frequency modulated signal. To adjust the slope, It is a time series.

[0028] Optionally, the step of reconstructing the signal using the frequency modulation line of the linear frequency modulated signal and the peak information in the logarithmic time spectrum to obtain the linear frequency modulated reconstructed signal includes:

[0029] The signal is reconstructed by taking the largest amplitude value in the amplitude sequence of the maximum peak value, the initial frequency value of the linear frequency modulated signal, and the modulation slope, and the reconstructed linear frequency modulated signal is obtained.

[0030] Optionally, the echo signal frequency modulation line satisfies the following formula:

[0031]

[0032] in, Indicates the echo signal frequency modulation line. This is the initial frequency value of the echo signal.

[0033] Optionally, the echo delay is determined based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, satisfying the following formula:

[0034]

[0035]

[0036] in, Indicates the echo delay amount. This represents the difference in initial frequencies between the linear frequency modulated signal and the echo signal.

[0037] Secondly, this application provides an echo delay determination device for a linear frequency modulated (FM) sound signal, comprising:

[0038] The processing module is used to perform time-varying bandpass filtering on the acquired acoustic signal to obtain the time-varying bandpass filtered acoustic signal;

[0039] The processing module is also used to perform a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the signal time spectrum, and to take the logarithm of the signal time spectrum to obtain the logarithmic time spectrum;

[0040] The determination module is used to determine the peak information in the logarithmic time spectrum, fit the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determine the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal.

[0041] The processing module is also used to reconstruct the signal using the frequency modulation line of the linear frequency modulated signal and the peak information in the logarithmic time spectrum to obtain the linear frequency modulated reconstructed signal;

[0042] The processing module is also used to take the logarithm of the linear frequency modulated reconstructed signal after short-time Fourier transform to obtain the reconstructed spectrum, and to obtain the difference spectrum by subtracting the reconstructed spectrum from the logarithmic spectrum.

[0043] The determining module is further configured to determine the peak information in the difference spectrum, fit the echo signal frequency modulation line based on the peak information in the difference spectrum, and determine the initial frequency of the echo signal based on the echo signal frequency modulation line.

[0044] The determining module is further configured to determine the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, and to determine the echo delay based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal.

[0045] Thirdly, this application provides an echo delay determination device for a linear frequency modulated (FM) sound signal, comprising:

[0046] Memory;

[0047] processor;

[0048] The memory stores computer-executed instructions;

[0049] The processor executes computer execution instructions stored in the memory to implement the method for determining the echo delay of a linear frequency modulated acoustic signal as described in the first aspect and various possible implementations thereof.

[0050] Fourthly, this application provides a computer storage medium having a computer program stored thereon, the computer program being executed by a processor to implement the method for determining the echo delay of a linear frequency modulated sound signal as described in the first aspect and various possible implementations of the first aspect above.

[0051] This application provides a method, apparatus, and device for determining the echo delay of a linear frequency modulated (LFM) acoustic signal. The method involves performing a time-varying bandpass filter on the acquired acoustic signal to obtain a time-varying bandpass filtered acoustic signal; performing a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the signal's time spectrum; taking the logarithm of the signal's time spectrum to obtain the logarithmic time spectrum; determining the peak information in the logarithmic time spectrum; fitting the LFM signal's frequency modulation line based on the peak information in the logarithmic time spectrum; determining the initial frequency of the LFM signal based on the LFM signal's frequency modulation line; and utilizing the LFM signal's frequency modulation line and the peak information in the logarithmic time spectrum... The signal is reconstructed to obtain a linear frequency modulated (LFM) reconstructed signal. The LFM reconstructed signal is then subjected to a short-time Fourier transform, and the logarithm is taken to obtain the reconstructed spectrum. The difference between the reconstructed spectrum and the logarithmic short-time Fourier transform spectrum is obtained to obtain the differenced spectrum. Peak information in the differenced spectrum is determined, and the echo signal frequency modulation line is fitted based on this peak information. The initial frequency of the echo signal is determined based on the echo signal frequency modulation line. The difference between the initial frequencies of the LFM signal and the echo signal is determined, and the echo delay is determined based on this difference. This method has strong anti-interference capability and improves the accuracy of echo delay calculation. Attached Figure Description

[0052] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0053] Figure 1 A flowchart illustrating the method for determining the echo delay of a linear frequency modulated acoustic signal provided in an embodiment of this application;

[0054] Figure 2 A time-domain diagram of the acoustic signal acquired by the acoustic sensor provided in the embodiments of this application;

[0055] Figure 3 Logarithmic time-frequency spectrum of acoustic signals acquired by the acoustic sensor provided in the embodiments of this application;

[0056] Figure 4The logarithmic time-frequency spectrum of the time-varying bandpass filtered signal provided in the embodiments of this application;

[0057] Figure 5 The frequency modulation line for the fitted linear frequency modulation signal provided in the embodiments of this application;

[0058] Figure 6 The spectrum obtained by subtracting the reconstructed spectrum from the logarithmic spectrum provided in the embodiments of this application;

[0059] Figure 7 The fitted echo signal frequency modulation line provided in the embodiments of this application;

[0060] Figure 8 A schematic diagram of the structure of the echo delay determination device for linear frequency modulated sound signals provided in the embodiments of this application;

[0061] Figure 9 This is a schematic diagram of the device for determining the echo delay of a linear frequency modulated sound signal provided in an embodiment of this application.

[0062] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0065] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0066] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0067] Figure 1 This is a flowchart illustrating the method for determining the echo delay of a linear frequency modulated audio signal provided in an embodiment of this application. Figure 1 As shown, the method for determining the echo delay of a linear frequency modulated (FM) audio signal provided in this embodiment includes:

[0068] S1: Perform time-varying bandpass filtering on the acquired acoustic signal to obtain the time-varying bandpass filtered acoustic signal.

[0069] Specifically, it includes the following steps:

[0070] S11: Acquire the first linear frequency modulated signal generated by the signal generator, construct a second linear frequency modulated signal with reversed slope based on the slope of the first linear frequency modulated signal, multiply the second linear frequency modulated signal with the acquired acoustic signal to obtain the multiplication result.

[0071] For example, the echo delay determination method for linear frequency modulated sound signals provided in this embodiment can be used to calculate the echo delay of pipeline blockage, thereby locating the pipeline blockage. Specifically, the signal sampling frequency is set. =5120Hz, the initial frequency of the linear frequency modulated signal generated by the signal generator. =20Hz, cutoff frequency =52Hz, frequency modulation slope =0.4Hz / s, sampling time =80s. Install the measuring device, with the excitation sound source installed at the port of the pipe to be tested, and the sound sensor installed at the front end of the excitation sound source.

[0072] For example, the acoustic sensor collects acoustic signals inside the tube. Its signal time-domain plot is as follows Figure 2 As shown, noise and interference are present in the acquired acoustic signal, making it impossible to determine the echo time. Acoustic signal The logarithmic time spectrum is as follows Figure 3 As shown, the main interference components are higher-order excitations and their echo signals. Time-varying bandpass filtering. Constructing a linear frequency modulated signal with inverted slope. Its initial frequency =50Hz, tuning slope is = -0.4Hz / s. A linear frequency modulated signal with inverted slope. Acoustic signals Multiply to get The calculation formula is:

[0073] .

[0074] S12: Use a bandpass filter to filter the multiplication result to obtain the bandpass filtered signal.

[0075] For example, using a bandpass filter to... Filtering yields the bandpass filtered signal. The upper cutoff frequency of the bandpass filter used =75Hz, lower cutoff frequency =68Hz.

[0076] S13: Multiply the complex conjugate signal of the second linear frequency modulated signal with the bandpass filtered signal to obtain the time-varying bandpass filtered signal.

[0077] For example, take a linear frequency modulated signal with inverted slope. complex conjugate signal ,Will With the bandpass filtered signal Multiply to obtain the time-varying bandpass filtered signal. The calculation formula is:

[0078] .

[0079] S2: Perform a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the time spectrum of the signal, and take the logarithm of the time spectrum to obtain the logarithmic time spectrum.

[0080] Specifically, a Gaussian window is used as the analysis window to divide the time-varying bandpass filtered acoustic signal into frames to obtain multiple frames of sub-signals; the sub-signal spectrum is obtained by fast Fourier transform of each frame of sub-signal, and the sub-signal spectra are combined into a complete signal time spectrum according to the frame order; the logarithm of the complete signal time spectrum is taken to obtain the logarithmic time spectrum.

[0081] For example, a Gaussian window is used as the analysis window to analyze the time-varying bandpass filtered signal. With frame length Step length Perform frame segmentation to obtain Frame signal ,in Indicates the frame number. The Fast Fourier Transform (FFT) of each frame's sub-signal yields the sub-signal spectrum. The sub-signal spectrum is arranged in frame order. When the spectrum is complete Time spectrum The spectrum when the logarithm is taken is the spectrum. The calculation formula is:

[0082] .

[0083] For example, Figure 4 The logarithmic time-frequency spectrum of the signal after time-varying bandpass filtering shows that higher-order excitation and its echo have been effectively suppressed, with only the linear frequency modulated excitation signal and its echo signal remaining in the time-frequency spectrum. The frequencies of the excitation and echo signals increase linearly with time.

[0084] S3: Determine the peak information in the logarithmic time spectrum, fit the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determine the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal.

[0085] Specifically, determining the peak information in the logarithmic time spectrum includes: extracting the maximum peak value of each sub-signal spectrum in the logarithmic time spectrum, recording the amplitude and corresponding frequency of each maximum peak value; arranging the amplitude and corresponding frequency of each maximum peak value according to the order of the sub-signals to form the amplitude sequence and frequency sequence of the maximum peak value; and using the least squares method to fit the frequency sequence and time sequence of the maximum peak value to obtain the frequency modulation line of the linear frequency modulation signal.

[0086] For example, extract The maximum peak value in the neutron signal spectrum is used to obtain the amplitude sequence of the maximum peak value. and frequency sequence Based on frequency sequences and time series The frequency modulation line of the linear frequency modulation signal was obtained by fitting using the least squares method. The calculation formula is:

[0087]

[0088] in, This represents the frequency modulation line for a linear frequency modulation signal. The initial frequency value of the linear frequency modulated signal. To adjust the slope, It is a time series.

[0089] For example, Figure 5 The frequency modulation line of the fitted linear frequency modulation signal can be estimated. =24.460426Hz, =0.400207Hz / s.

[0090] S4: Reconstruct the signal using the frequency modulation line of the linear frequency modulated signal and the peak information in the logarithmic time spectrum to obtain the reconstructed linear frequency modulated signal.

[0091] Specifically, the signal is reconstructed based on the amplitude sequence and frequency sequence of the maximum peak value and the estimation result of the first parameter to obtain the reconstructed signal.

[0092] For example, extracting the maximum peak sequence The largest element in , combined initial frequency value and slope Reconstructing the linear frequency modulation reconstructed signal .

[0093] S5: After performing a short-time Fourier transform on the linear frequency modulated reconstructed signal, take the logarithm to obtain the reconstructed spectrum. Subtract the reconstructed spectrum from the logarithmic spectrum to obtain the differenced spectrum.

[0094] Specifically, for linear frequency modulation reconstructed signals The reconstructed spectrum is obtained by performing a short-time Fourier transform and taking the logarithm. The spectrum will be reconstructed. Logarithmic time spectrum The difference is used to obtain the spectrum. It satisfies the following formula:

[0095] .

[0096] For example, Figure 6 The spectrum obtained by subtracting the reconstructed spectrum from the logarithmic spectrum provided in the embodiments of this application is as follows: Figure 6 As shown, after subtraction, only the echo signal remains in the spectrum.

[0097] S6: Determine the peak information in the spectrum after difference, fit the echo signal frequency modulation line based on the peak information in the spectrum after difference, and determine the initial frequency of the echo signal based on the echo signal frequency modulation line.

[0098] Step S6 is similar to the process in step S3 above, which involves "determining the peak information in the logarithmic time spectrum, fitting the frequency modulation line of the linear frequency modulation signal based on the peak information in the logarithmic time spectrum, and determining the initial frequency of the linear frequency modulation signal based on the frequency modulation line of the linear frequency modulation signal", and will not be described again here.

[0099] Specifically, echo signal frequency modulation line It satisfies the following formula:

[0100]

[0101] in, This is the initial frequency value of the echo signal.

[0102] For example, such as Figure 7 As shown, the frequency modulation line of the fitted echo signal can be estimated. =20.416340Hz.

[0103] S7: Determine the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, and determine the echo delay based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal.

[0104] Specifically, calculation and The difference in initial frequencies The calculation formula is:

[0105] .

[0106] echo delay The calculation formula is:

[0107]

[0108] in, Indicates the echo delay amount. This represents the difference in initial frequencies between the linear frequency modulated signal and the echo signal.

[0109] Understandably, obtaining the initial frequency difference between the linearly modulated (LFM) signal obtained through linear fitting in the time-frequency characteristic domain and the LFM line of the echo signal can smooth out interference such as local noise and instantaneous fluctuations in the data, as well as deviations caused by accidental interference in the frequency difference calculation of a single data point. Directly calculating the delay using the time-frequency characteristics of the LFM signal and the echo signal avoids the filtering and complex algorithm processing of traditional pulse-echo methods, reducing the computational load and effectively minimizing the time delay calculation errors caused by noise and clutter interference in long-distance single-pulse echoes.

[0110] Furthermore, the velocity of sound inside the tube can be combined with... Calculate the distance from the pipe blockage to the pipe port. The calculation formula is:

[0111] .

[0112] This embodiment proposes a method for determining the echo delay of a linear frequency modulated (LFM) acoustic signal. The method involves performing a time-varying bandpass filter on the acquired acoustic signal to obtain a time-varying bandpass filtered acoustic signal; performing a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the signal's time spectrum; taking the logarithm of the signal's time spectrum to obtain the logarithmic time spectrum; determining the peak information in the logarithmic time spectrum; fitting the LFM signal's frequency modulation line based on the peak information in the logarithmic time spectrum; determining the initial frequency of the LFM signal based on the LFM signal's frequency modulation line; and using the LFM signal to modulate... The method reconstructs the linear frequency modulated (LFM) reconstructed signal by extracting peak information from the frequency line and the logarithmic time-frequency spectrum. The reconstructed LFM signal is then subjected to a short-time Fourier transform, and the logarithm is taken to obtain the reconstructed spectrum. The difference between the reconstructed spectrum and the logarithmic time-frequency spectrum is calculated to obtain the differenced spectrum. The peak information in the differenced spectrum is determined, and the LFM frequency line of the echo signal is fitted based on this peak information. The initial frequency of the echo signal is then determined based on the LFM frequency line. The difference between the initial frequencies of the LFM signal and the echo signal is determined, and the echo delay is calculated based on this difference. This method has strong anti-interference capabilities and improves the accuracy of echo delay calculation.

[0113] Figure 8 This is a schematic diagram of the structure of the echo delay determination device for linear frequency modulated audio signals provided in an embodiment of this application. Figure 8 As shown, the echo delay determination device 200 for linear frequency modulated audio signals provided in this embodiment includes:

[0114] The processing module 201 is used to perform time-varying bandpass filtering on the acquired acoustic signal to obtain the time-varying bandpass filtered acoustic signal.

[0115] The processing module 201 is also used to perform a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the time spectrum of the signal, and take the logarithm of the time spectrum of the signal to obtain the logarithmic time spectrum;

[0116] The determination module 202 is used to determine the peak information in the logarithmic time spectrum, fit the frequency modulation line of the linear frequency modulation signal based on the peak information in the logarithmic time spectrum, and determine the initial frequency of the linear frequency modulation signal based on the frequency modulation line of the linear frequency modulation signal.

[0117] The processing module 201 is further configured to reconstruct the signal using the frequency modulation line of the linear frequency modulated signal and the peak information in the logarithmic time spectrum to obtain the linear frequency modulated reconstructed signal;

[0118] The processing module 201 is further configured to take the logarithm of the linear frequency modulated reconstructed signal after short-time Fourier transform to obtain the reconstructed spectrum, and to obtain the difference spectrum by subtracting the reconstructed spectrum from the logarithmic spectrum.

[0119] The determining module 202 is further configured to determine the peak information in the difference spectrum, fit the echo signal frequency modulation line based on the peak information in the difference spectrum, and determine the initial frequency of the echo signal based on the echo signal frequency modulation line.

[0120] The determining module 202 is further configured to determine the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, and to determine the echo delay based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal.

[0121] The echo delay determination device for linear frequency modulated sound signals provided in this embodiment can execute the echo delay determination method for linear frequency modulated sound signals provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0122] Figure 9 This is a schematic diagram of the structure of the echo delay determination device for linear frequency modulated audio signals provided in an embodiment of this application. Figure 9 As shown in the embodiment of this application, the echo delay determination device for linear frequency modulated sound signals 300 includes: a receiver 301, a transmitter 302, a processor 303, and a memory 304.

[0123] Receiver 301 is used to receive instructions and data;

[0124] Transmitter 302 is used to send commands and data;

[0125] Memory 304 is used to store computer-executed instructions;

[0126] Processor 303 is used to execute computer execution instructions stored in memory 304 to implement the various steps of the method for determining the echo delay of a linear frequency modulated (LFM) sound signal in the above embodiments. For details, please refer to the relevant descriptions in the embodiments of the method for determining the echo delay of a LFM sound signal.

[0127] Optionally, the memory 304 can be either standalone or integrated with the processor 303.

[0128] When the memory 304 is set up independently, the electronic device also includes a bus for connecting the memory 304 and the processor 303.

[0129] This application embodiment also provides a computer storage medium storing computer execution instructions. When the processor executes the computer execution instructions, it implements the echo delay determination method for linear frequency modulated sound signals executed by the above-described echo delay determination device for linear frequency modulated sound signals.

[0130] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0131] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0132] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for determining the echo delay of a linear frequency modulated (LFM) acoustic signal, characterized in that, The method includes: The acquired acoustic signal is subjected to time-varying bandpass filtering to obtain the time-varying bandpass filtered acoustic signal; A short-time Fourier transform is performed on the time-varying bandpass filtered acoustic signal to obtain the time spectrum of the signal, and the logarithm of the time spectrum is taken to obtain the logarithmic time spectrum. Determine the peak information in the logarithmic time spectrum, fit the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determine the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal. The signal is reconstructed using the frequency modulation line and peak information in the logarithmic time spectrum of the linear frequency modulated signal to obtain the reconstructed linear frequency modulated signal; The reconstructed spectrum is obtained by taking the logarithm of the short-time Fourier transform of the linear frequency modulated reconstructed signal. The difference between the reconstructed spectrum and the logarithmic spectrum is obtained as the difference spectrum. Determine the peak information in the spectrum after subtraction, fit the echo signal frequency modulation line based on the peak information in the spectrum after subtraction, and determine the initial frequency of the echo signal based on the echo signal frequency modulation line. Determine the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, and then determine the echo delay based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal.

2. The method according to claim 1, characterized in that, The process of performing time-varying bandpass filtering on the acquired acoustic signal to obtain the time-varying bandpass filtered acoustic signal includes: Acquire the first linear frequency modulated signal generated by the signal generator, construct a second linear frequency modulated signal with reversed slope based on the slope of the first linear frequency modulated signal, and multiply the second linear frequency modulated signal with the acquired acoustic signal to obtain the multiplication result; The multiplication result is filtered using a bandpass filter to obtain the bandpass-filtered signal; The complex conjugate signal of the second linear frequency modulated signal is multiplied by the bandpass filtered signal to obtain the time-varying bandpass filtered acoustic signal.

3. The method according to claim 2, characterized in that, The step of performing a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the signal's time spectrum includes: A Gaussian window is used as the analysis window to divide the time-varying bandpass filtered acoustic signal into frames, resulting in multi-frame sub-signals. The sub-signal spectrum is obtained by fast Fourier transform of each frame sub-signal, and the sub-signal spectra are combined into a complete signal time spectrum according to the frame order.

4. The method according to claim 3, characterized in that, The determination of peak information in the logarithmic spectrum includes: Extract the maximum peak value of each sub-signal spectrum in the logarithmic time spectrum, and record the amplitude and corresponding frequency of each maximum peak value; The amplitude and corresponding frequency of each maximum peak are arranged in the order of the sub-signals to form the amplitude sequence and frequency sequence of the maximum peak.

5. The method according to claim 4, characterized in that, The step of fitting the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determining the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal, includes: Based on the frequency sequence and time sequence of the maximum peak value, the frequency modulation line of the linear frequency modulation signal is obtained by least squares fitting. The frequency modulation line of the linear frequency modulation signal satisfies the following formula: ； in, This represents the frequency modulation line for a linear frequency modulation signal. The initial frequency value of the linear frequency modulated signal. To adjust the slope, It is a time series.

6. The method according to claim 5, characterized in that, The process of reconstructing the signal using the frequency modulation line of the linear frequency modulated signal and the peak information in the logarithmic time spectrum to obtain the linear frequency modulated reconstructed signal includes: The signal is reconstructed by taking the largest amplitude value in the amplitude sequence of the maximum peak value, the initial frequency value of the linear frequency modulated signal, and the modulation slope, and the reconstructed linear frequency modulated signal is obtained.

7. The method according to claim 6, characterized in that, The echo signal frequency modulation line satisfies the following formula: ； in, Indicates the echo signal frequency modulation line. This is the initial frequency value of the echo signal.

8. The method according to claim 7, characterized in that, The echo delay is determined based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, satisfying the following formula: ； ； in, Indicates the echo delay amount. This represents the difference in initial frequencies between the linear frequency modulated signal and the echo signal.

9. A device for determining the echo delay of a linear frequency modulated (FM) sound signal, characterized in that, The device includes: The processing module is used to perform time-varying bandpass filtering on the acquired acoustic signal to obtain the time-varying bandpass filtered acoustic signal; The processing module is also used to perform a short-time Fourier transform on the time-varying bandpass filtered acoustic signal to obtain the signal time spectrum, and to take the logarithm of the signal time spectrum to obtain the logarithmic time spectrum; The determination module is used to determine the peak information in the logarithmic time spectrum, fit the frequency modulation line of the linear frequency modulated signal based on the peak information in the logarithmic time spectrum, and determine the initial frequency of the linear frequency modulated signal based on the frequency modulation line of the linear frequency modulated signal. The processing module is also used to reconstruct the signal using the frequency modulation line of the linear frequency modulated signal and the peak information in the logarithmic time spectrum to obtain the linear frequency modulated reconstructed signal; The processing module is also used to take the logarithm of the linear frequency modulated reconstructed signal after short-time Fourier transform to obtain the reconstructed spectrum, and to obtain the difference spectrum by subtracting the reconstructed spectrum from the logarithmic spectrum. The determining module is further configured to determine the peak information in the difference spectrum, fit the echo signal frequency modulation line based on the peak information in the difference spectrum, and determine the initial frequency of the echo signal based on the echo signal frequency modulation line. The determining module is further configured to determine the difference between the initial frequencies of the linear frequency modulated signal and the echo signal, and to determine the echo delay based on the difference between the initial frequencies of the linear frequency modulated signal and the echo signal.

10. A device for determining the echo delay of a linear frequency modulated (FM) sound signal, characterized in that, include: Memory; processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method for determining the echo delay of a linear frequency modulated sound signal as described in any one of claims 1-8.

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