CN114167424A

CN114167424A - Sound wave distance measuring method, device and system

Info

Publication number: CN114167424A
Application number: CN202210124608.XA
Authority: CN
Inventors: 张祺
Original assignee: Beijing Startest Tec Co Ltd
Current assignee: Beijing Startest Tec Co Ltd
Priority date: 2022-02-10
Filing date: 2022-02-10
Publication date: 2022-03-11
Anticipated expiration: 2042-02-10
Also published as: CN114167424B

Abstract

The invention discloses a method, a device and a system for measuring distance by sound waves, which are used for solving the problem of inaccurate distance measurement by sound waves. The scheme provided by the application comprises the following steps: sending a ranging sound wave signal to a target to be measured; receiving an acoustic echo signal reflected by a target to be detected based on a ranging acoustic signal; determining a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo; performing similarity comparison on the first reflected sound wave signal and the second reflected sound wave signal to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal; and determining the distance between the first reflected sound wave signal and the target to be measured according to the absolute delay between the first reflected sound wave signal and the adjacent reflected sound wave signal. The scheme utilizes the similarity between adjacent echoes to reduce the interference of distortion on waveform measurement and effectively improve the measurement accuracy. The real time of the echo does not need to be determined, and the problem of inaccurate measurement of the initial time of the reflected sound wave is avoided.

Description

Sound wave distance measuring method, device and system

Technical Field

The invention relates to the field of acoustic ranging, in particular to an acoustic ranging method, device and system.

Background

In the exploration field, detection can be realized by utilizing the propagation characteristics of waves. For example, the sound wave can be used for underwater detection, and submarine topography exploration ranging, object searching and the like can be realized according to the time difference between the emitted sound wave and the received echo. In particular, the acoustic wave used for detection may also be referred to as an acoustic signal. The emitted sound waves are transmitted in a medium such as air or water and reach an obstacle, and then are reflected on the surface of the obstacle, and the reflected sound waves can be called acoustic echoes.

In practical applications, the medium through which the sound waves propagate tends to be inhomogeneous, and other sounds may also be entrained in the environment, which causes the acoustic echo to be entrained with noise. In addition, the received acoustic echo is often distorted by hardware devices. The above causes difficulty in determining the starting time in the acoustic echo, which in turn leads to inaccurate ranging.

How to improve the accuracy of sound wave range finding is the technical problem that this application will solve.

Disclosure of Invention

An object of the embodiments of the present application is to provide a method, an apparatus, and a system for acoustic ranging, so as to solve the problem of inaccurate acoustic ranging.

In a first aspect, a method for measuring a distance by using an acoustic wave is provided, which includes:

sending a ranging sound wave signal to a target to be measured;

receiving an acoustic echo signal reflected by the target to be detected based on the ranging acoustic signal, wherein the acoustic echo signal comprises a plurality of reflected acoustic signals based on time sequence;

determining a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo, the second reflected acoustic wave signal comprising a target reflected acoustic wave signal chronologically adjacent to the first reflected acoustic wave signal;

performing similarity comparison on the first reflected sound wave signal and the second reflected sound wave signal to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal;

and determining the distance between the target and the target to be detected according to the absolute delay between the first reflected sound wave signal and the target reflected sound wave signal, wherein the absolute delay is determined according to the time period of the first reflected sound wave signal in the sound echo signal and the time period of the target reflected sound wave signal in the sound echo signal.

Optionally, the ranging sound wave signal includes a preset frequency f₀Is preset number N₀A pulsed acoustic signal, said f₀Is a positive number, N₀Is an integer greater than 1;

wherein determining a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo comprises:

determining the number K of target echoes and the starting moment of the first echo according to the acoustic echo signals, wherein K is more than 1 and less than or equal to N₀The first echo starting time is the time when the first amplitude of the nth reflected sound wave signal in the sound echo signals is larger than the preset amplitude;

at the predetermined frequency f₀Sampling the acoustic echo signals after the first echo starting moment to obtain the first reflected acoustic wave signals containing K pulse acoustic wave signals;

at the predetermined frequency f₀And sampling the acoustic echo signal after the first reflected acoustic wave signal to obtain the second reflected acoustic wave signal.

Optionally, at the preset frequency f₀Sampling the acoustic echo signal after the first echo start time to obtain the first reflected acoustic wave signal including K pulsed acoustic wave signals, comprising:

determining the first time with the amplitude value of 0 after the first echo starting time as a second echo starting time according to the acoustic echo signal;

taking the starting moment of the second echo as a starting point and the preset frequency f₀Sampling the acoustic echo signal to obtain the first reflected acoustic wave signal comprising K pulsed acoustic wave signals.

Optionally, before performing a similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal, the method further includes:

performing symbolization on the first reflected acoustic wave signal and the second reflected acoustic wave signal according to a reference amplitude value to obtain a first symbolized signal and a second symbolized signal;

wherein performing a similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal to determine a time period in which the target reflected acoustic wave signal is located from the second reflected acoustic wave signal includes:

performing a cross-correlation operation on the first and second symbolized signals to determine a time period of the target reflected acoustic wave signal from the second reflected acoustic wave signal.

Optionally, performing symbolization on the first reflected acoustic wave signal and the second reflected acoustic wave signal according to a reference amplitude value to obtain a first symbolized signal and a second symbolized signal, including:

and recording the waveform which is greater than or equal to the reference amplitude as a first symbol value and recording the waveform which is smaller than the reference amplitude as a second symbol value according to the first reflected sound wave signal and the second reflected sound wave signal so as to obtain a first symbolized signal and a second symbolized signal.

performing sequence interpolation on the first reflected acoustic wave signal and the second reflected acoustic wave signal respectively based on a time sequence;

and performing cross-correlation operation on the first reflected sound wave signal subjected to the sequence interpolation and the second reflected sound wave signal subjected to the sequence interpolation to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal.

In a second aspect, there is provided an acoustic ranging apparatus comprising:

the sending module is used for sending a ranging sound wave signal to a target to be measured;

the receiving module is used for receiving an acoustic echo signal reflected by the target to be detected based on the ranging acoustic signal, wherein the acoustic echo signal comprises a plurality of reflected acoustic signals based on time sequence;

a first determining module that determines a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo, the second reflected acoustic wave signal including a target reflected acoustic wave signal that is chronologically adjacent to the first reflected acoustic wave signal;

the second determining module is used for performing similarity comparison on the first reflected sound wave signal and the second reflected sound wave signal so as to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal;

and the third determining module is used for determining the distance between the target and the target to be detected according to the absolute delay between the first reflected sound wave signal and the target reflected sound wave signal, wherein the absolute delay is determined according to the time period of the first reflected sound wave signal in the sound echo signal and the time period of the target reflected sound wave signal in the sound echo signal.

In a third aspect, there is provided an acoustic ranging system comprising:

the transmitting transducer is used for transmitting a ranging sound wave signal to a target to be measured;

the receiving transducer is used for receiving an acoustic echo signal reflected by the target to be detected based on the ranging acoustic signal, wherein the acoustic echo signal comprises a plurality of reflected acoustic signals based on time sequence;

a comparator communicatively coupled to the receiving transducer to determine a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo, the second reflected acoustic wave signal comprising a target reflected acoustic wave signal chronologically adjacent to the first reflected acoustic wave signal;

a processor in communication with the transmitting transducer and the comparator, for performing a similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal to determine a time period in which the target reflected acoustic wave signal is located from the second reflected acoustic wave signal;

the processor is further configured to determine a distance from the target to be measured according to an absolute delay between the first reflected acoustic wave signal and the target reflected acoustic wave signal, where the absolute delay is determined according to a time period of the first reflected acoustic wave signal in the acoustic echo signal and a time period of the target reflected acoustic wave signal in the acoustic echo signal.

In a fourth aspect, an electronic device is provided, the electronic device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the computer program, when executed by the processor, implementing the steps of the method according to the first aspect.

In a fifth aspect, a computer-readable storage medium is provided, on which a computer program is stored, which computer program, when being executed by a processor, realizes the steps of the method as in the first aspect.

In the embodiment of the application, a ranging sound wave signal is sent to a target to be measured; receiving an acoustic echo signal reflected by a target to be detected based on a ranging acoustic signal; determining a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo; performing similarity comparison on the first reflected sound wave signal and the second reflected sound wave signal to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal; and determining the distance between the first reflected sound wave signal and the target to be measured according to the absolute delay between the first reflected sound wave signal and the adjacent reflected sound wave signal. The scheme utilizes the similarity between adjacent echoes to reduce the interference of distortion on waveform measurement and effectively improve the measurement accuracy. The real time of the echo does not need to be determined, and the problem of inaccurate measurement of the initial time of the reflected sound wave is avoided.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1a is a schematic diagram of emitted sound waves and acoustic echoes in a sound wave ranging scenario;

FIG. 1b is a schematic diagram of the location of the acoustic echo arrival point in the acoustic echo;

FIG. 2 is a schematic diagram of the location of a user-selected acoustic echo arrival point and the location of a true acoustic echo arrival point;

FIG. 3a is a schematic flow chart of a method for measuring distance by acoustic waves according to an embodiment of the present invention;

FIG. 3b is a schematic diagram of waveforms of a transmitted sound wave and an acoustic echo according to an embodiment of the present invention;

FIG. 4 is a second flowchart illustrating a method of acoustic ranging according to an embodiment of the present invention;

FIG. 5 is a third schematic flow chart of a method for measuring distance by using sound waves according to an embodiment of the present invention;

FIG. 6 is a fourth flowchart illustrating a method of acoustic ranging according to an embodiment of the present invention;

FIG. 7 is a fifth flowchart illustrating a method of acoustic ranging according to an embodiment of the present invention;

FIG. 8 is a sixth flowchart illustrating a method of acoustic ranging according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of an acoustic ranging device according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of an acoustic ranging system according to an embodiment of the present invention;

FIG. 11 is a second schematic structural diagram of an acoustic ranging system according to an embodiment of the present invention;

FIG. 12 is a schematic waveform of an acoustic echo analog signal symbolized by an analog comparator according to an embodiment of the present invention;

FIG. 13 is a parameter schematic of a comparator in a zero crossing detection circuit according to an embodiment of the present invention;

FIG. 14 is a schematic flow chart of an embodiment of the present invention from acoustic echo samples sign { fk (t) };

FIG. 15 is a waveform diagram illustrating sampling of K waveforms with acoustic echoes according to one embodiment of the invention;

FIG. 16a is a schematic diagram of a simulation waveform under high SNR conditions according to an embodiment of the present invention;

FIG. 16b is a schematic diagram of a simulated waveform under low SNR conditions according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The reference numbers in the present application are only used for distinguishing the steps in the scheme and are not used for limiting the execution sequence of the steps, and the specific execution sequence is described in the specification.

The scheme provided by the embodiment of the application can be applied to sound wave ranging in air, sound wave ranging in water or sound wave ranging scenes of other media. In the field of acoustic signal measurement, acoustic propagation delay measurement is a key technology for measuring distance and sound velocity acoustically, and is widely used in sound velocity meters, distance meters, various sonar and positioning systems. The acoustic echo is a sound wave reflected by an object, and can be received by the receiving transducer and converted into a storable signal. As shown in fig. 1a, the receiving transducer receiving the acoustic echo often has "spindle-shaped" amplitude modulation distortion. As shown in fig. 1b, the boundary of the acoustic echo with amplitude modulation distortion is not clear, and the boundary is often mixed in noise, so that it is difficult to accurately detect the real time interval of the acoustic echo, and further, it is difficult to accurately measure the distance.

The boundary of the acoustic echo which is difficult to accurately detect can be selected by manual selection. As shown in fig. 2, the boundary of the acoustic echo selected in this way is subjective, and it is difficult to select a real arrival point of the acoustic echo.

Also, the acoustic wave has specificity compared to other types of waves, and it is difficult to apply other types of echo detection methods to the acoustic wave. For example, if the light wave is used for distance measurement, the chip can directly identify the real arrival time of the light echo because the light echo has obvious edges and often has obvious level edges. In addition, compared with light waves, sound waves have stronger penetrability in partial scenes, and how to improve the accuracy of sound wave distance measurement is a technical problem to be solved by the scheme.

The above scheme for identifying the echo time based on the chip can be implemented by using a time-to-digital converter (TDC). The TDC chip can directly measure the flow rate, the wind speed and the like of the wave in a partial scene, but the time difference measured in the application scene is characterized by relative two-way time difference, namely, the time difference is characterized by relative time difference and does not represent the real time period of the wave.

In order to solve the problems in the prior art, an embodiment of the present application provides an acoustic ranging method, as shown in fig. 3a, including the following steps:

s31: and sending a ranging sound wave signal to the target to be measured.

The ranging sound wave signal may be a sinusoidal signal or a pulse signal having a preset amplitude, a preset frequency, and a preset phase. The periodic signal is sent as a ranging sound wave signal, so that the efficiency of processing an acoustic echo signal in the subsequent step can be improved, and the ranging accuracy is improved.

Optionally, the ranging acoustic signal may be sent by the transmitting transducer, and the ranging acoustic signal may be preset in the transmitting transducer, or sent to the transmitting transducer in the form of an electrical signal by a processor in communication connection with the transmitting transducer, and sent to the target to be measured in the form of an acoustic signal after the electrical signal is subjected to electro-acoustic conversion by the transmitting transducer. The distance measurement sound wave signal may also be referred to as probe sound energy.

The factors representing the waveform of the ranging sound wave signal are amplitude, frequency and initial phase. An example of transmitting sound waves is a fixed frequency f₀A single-cycle sine or cosine pulse of fixed amplitude and initial phase phi = 0. To improve measurement reliability, one example is: in single acoustic propagation delay measurement, N is continuously transmitted by an acoustic measurement system₀The single-period pulse is used as a transmitting sound wave, and can be selected and set according to actual requirements in practical application.

S32: and receiving an acoustic echo signal reflected by the target to be detected based on the ranging acoustic signal, wherein the acoustic echo signal comprises a plurality of reflected acoustic signals based on time sequence.

Wherein the acoustic echo signals may be captured by a receiving transducer. The ranging acoustic wave signal transmitted in the step S31 propagates in the medium for a certain time delay and reaches the surface of the target to be measured, and propagates in the medium for a certain time delay and reaches the receiving transducer after being reflected. The receiving transducer converts the received acoustic echo signals into electrical signals for storage and subsequent processing by acoustic-to-electrical conversion.

As shown in fig. 3b, a time-sequence based diagram of the transmitted acoustic wave signal and the acoustic echo signal is shown. The transmitted sound wave signal is a ranging sound wave signal with a preset amplitude, a preset frequency and a preset phase. After the ranging sound wave signal is sent out, the acoustic echo signal is received through a certain sound propagation delay. Due to energy loss during transmission of the acoustic signal, the amplitude of the received first reflected acoustic signal is smaller than the amplitude of the transmitted acoustic signal.

Subsequently, the first reflected acoustic wave signal is reflected by the execution body of the present solution and then propagates to the target to be measured again, and is reflected by the target to be measured and then received and processed by the receiving transducer again, which is denoted as a second reflected acoustic wave in fig. 3 b.

As can be seen from fig. 3b, after the ranging sound wave signal is transmitted, a first reflected sound wave can be received with a certain sound propagation delay, and a second reflected sound wave can be received with a certain sound propagation delay. In practical applications, if the amplitude of the transmitted ranging sound wave signal is large, more reflected sound waves may be received, and the amplitude of each reflected sound wave signal in the acoustic echo signals is sequentially decreased based on the time sequence.

In addition, the acoustic echo undergoes spindle-shaped amplitude modulation distortion after passing through the receiving transducer, as shown by the reflected acoustic wave in fig. 3 b.

S33: determining a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo, the second reflected acoustic wave signal comprising a target reflected acoustic wave signal that is chronologically adjacent to the first reflected acoustic wave signal.

In this step, a first reflected acoustic wave signal is determined from the acoustic echo. The first reflected acoustic wave signal may be any one of the acoustic echo signals. In practical applications, in order to improve the accuracy of the subsequent similarity comparison, the first reflected sound wave signal in this step may be the first reflected sound wave signal in the acoustic echo.

In this step, the determined first reflected acoustic wave signal may be a part of the first reflected acoustic wave signal, or may be a signal including the complete first reflected acoustic wave signal and a part of the noise. In other words, in the present solution, it is not necessary to determine the specific time when the first reflected sound wave signal is received, and it is only necessary to intercept the signal including at least part of the first reflected sound wave.

Optionally, in this step, the acoustic echo signal may be identified based on a preset amplitude value to determine the first reflected acoustic wave signal. For example, a time when the amplitude of the acoustic echo signal is greater than or equal to a preset amplitude is determined, and the time is taken as a starting time, and the acoustic echo with a preset duration is intercepted as a first reflected acoustic wave signal. The specific interception duration can be determined according to the duration of the transmitted ranging sound wave signal. For example, assuming that the time duration of the transmitted ranging sound wave signal is 3 seconds, the preset time duration may be 2.5 seconds, so as to intercept at least a part of the first reflected sound wave from the sound echo as the first reflected sound wave in this step.

The second reflected acoustic wave signal in this step includes a target reflected acoustic wave signal adjacent to the first reflected acoustic wave signal on a time-series basis. For example, in the present example, the first reflected acoustic wave signal is the first reflected acoustic wave signal in the acoustic echo, and then the target reflected acoustic wave signal adjacent to the first reflected acoustic wave signal based on the time sequence is the second reflected acoustic wave signal.

In particular, the second one of the acoustic echo signals may be determined based on an acoustic propagation delay between the first reflected acoustic wave and the transmitted ranging acoustic wave signal. Theoretically, the acoustic propagation delay between the transmitted sound wave and the first reflected sound wave is equal to the acoustic propagation delay between the first reflected sound wave and the second reflected sound wave. To ensure that the determined second reflected acoustic signal contains a signal for performing a similarity comparison in a subsequent step, the time difference between the end time of the first reflected acoustic signal and the start time of the transmitted acoustic signal may be determined after the first reflected acoustic signal has been determined. Then, the end time of the first reflected sound wave signal is used as the start time of the second reflected sound wave signal, and the sound echo is intercepted based on the time difference to obtain the second reflected sound wave signal.

Referring to fig. 3b, since the second reflected sound wave is a second reflected sound wave of the first reflected sound wave, the second reflected sound wave has a similar waveform to the first reflected sound wave. The second reflected sound wave signal determined in the step contains the waveform similar to the first reflected sound wave signal, so that similarity comparison can be conveniently performed on the two reflected sound wave signals in the subsequent step.

Optionally, the second reflected acoustic signal may also include the first reflected acoustic signal. For example, the acoustic echo is recorded from the start time of transmitting the ranging acoustic wave signal. After the first reflected sound wave is determined, the time length of the acoustic echo before the starting time of the first reflected sound wave is determined as a propagation period. And continuously recording three acoustic echoes of the time length of the propagation period as a second reflected sound wave from the starting moment of transmitting the ranging sound wave signal. In the first propagation period duration, the transmitted sound wave propagates to the target to be measured and is reflected to the receiving transducer, the second propagation period duration comprises a first reflected sound wave, and the third propagation period duration comprises a second reflected sound wave.

S34: and performing similarity comparison on the first reflected sound wave signal and the second reflected sound wave signal so as to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal.

In this step, the similarity comparison may be performed by a cross-correlation algorithm, or may be implemented by other waveform comparison methods. The purpose of this step is to compare the first reflected acoustic wave signal with the second reflected acoustic wave signal, and determine the time period of the target reflected acoustic wave signal similar to the first reflected acoustic wave signal from the second reflected acoustic wave signal.

Due to the influence of energy loss of the sound wave signals in propagation and amplitude modulation distortion of the receiving transducer, the waveform of the first reflected sound wave is greatly different from that of the transmitted ranging sound wave signal, so that the real sound propagation delay cannot be determined by comparing the transmitted ranging sound wave signal with the first reflected sound wave signal. In the step, similarity comparison is carried out on the first reflected sound wave signal and the second reflected sound wave signal, each reflected sound wave in the sound echo usually has amplitude modulation distortion to a certain degree, and adjacent reflected sound waves have certain similarity. In other words, the target reflected acoustic wave signal is an acoustic wave of the first reflected acoustic wave signal propagating to the target to be measured and reflected back to the receiving transducer. After the time period of the target reflected sound wave signal is determined through the step, the time length of sound wave propagation can be determined according to the time period of the first reflected sound wave signal.

S35: and determining the distance between the target and the target to be detected according to the absolute delay between the first reflected sound wave signal and the target reflected sound wave signal, wherein the absolute delay is determined according to the time period of the first reflected sound wave signal in the sound echo signal and the time period of the target reflected sound wave signal in the sound echo signal.

The absolute delay in this step refers to a time delay based on an absolute time standard, not a relative delay. Specifically, the time period of the first reflected sound wave signal in the acoustic echo signal and the time period of the target reflected sound wave in the acoustic echo signal may be determined, and then the time delay may be determined based on the two time periods. Optionally, the time difference between the starting time of the time period of the first reflected sound wave signal in the acoustic echo signal and the starting time of the time period of the target reflected sound wave in the acoustic echo signal is determined as the absolute time delay.

The absolute delay represents the time difference of the first reflected sound wave signal which is transmitted to the target to be measured and reflected back to the receiving transducer, and the distance between the first reflected sound wave signal and the target to be measured can be determined based on the transmission speed of the sound wave and the absolute delay. For example, the product of the propagation speed of the acoustic wave and the above absolute delay time is determined as the distance from the object to be measured.

It should be noted that, in the solution provided in the embodiment of the present application, it is not necessary to determine the real start time of each reflected sound wave in the acoustic echo, and the first reflected sound wave signal, the second reflected sound wave signal, and the target reflected sound wave signal in the method refer to signals including at least part of the real reflected sound wave signal.

For the above step S34 in this embodiment of the present application, a method for implementing similarity comparison is provided below, in this embodiment, a cross-correlation algorithm is applied to implement similarity comparison, and a formula of the cross-correlation algorithm is as follows (1-1):

（1-1）

in connection with the examples provided in the embodiments of the present application, wherein:

f [ n ] represents a first reflected sound wave discrete time sequence in the acoustic echo;

g [ n ] represents a second reflected sound wave discrete time sequence in the acoustic echo;

n is a discrete time series time index;

n₀indexing the discrete time sequence delay;

n is the total length of the discrete time sequence;

a is a coefficient, related to N.

And performing cross correlation on the first reflected sound wave signal and the second reflected sound wave signal based on the formula (1-1), and determining the period of the target reflected sound wave based on the cross correlation result. In this example, assuming that the second reflected acoustic wave signal does not include the first reflected acoustic wave signal, then when n₀When the time equals to the sound propagation delay value, the cross-correlation result R_gf[n₀]The value is maximum. In actual execution, only from g [ n ]]And f [ n ]]The starting point of the sequence is continuously advancedLine 'sliding convolution' operation, observe when R_gf[n₀]When the maximum value is reached, namely the maximum correlation peak, the (n) corresponding to the maximum correlation peak is taken₀Time of day) represents the acoustic propagation delay. Wherein the acoustic propagation delay measurement resolution depends on g [ n ]]And f [ n ]]And the higher the sequence sampling point density of the sequence is, the higher the acoustic propagation delay measurement resolution is.

Based on the scheme provided by the above embodiment, optionally, the ranging sound wave signal includes a preset frequency f₀Is preset number N₀A pulsed acoustic signal, said f₀Is a positive number, N₀Is an integer greater than 1;

as shown in fig. 4, the step S33 includes:

s41: determining the number K of target echoes and the starting moment of the first echo according to the acoustic echo signals, wherein K is more than 1 and less than or equal to N₀The first echo starting time is the time when the first amplitude of the nth reflected sound wave signal in the sound echo signals is larger than the preset amplitude.

The preset amplitude can be an amplitude matched with the ranging sound wave signal, and the preset amplitude is smaller than the amplitude of the ranging sound wave signal and is used for distinguishing noise in the acoustic echo from the reflected sound wave. The number K of the target echoes determined in the step is less than or equal to the number of the pulse sound wave signals of the ranging sound wave signals, so that the first reflected sound wave signals are intercepted from the real first reflected sound wave signals in the sound echoes, and the noise after the first reflected sound wave signals are intercepted is avoided. In addition, in this step, the first echo starting time is determined according to the preset amplitude, if the amplitude of the acoustic echo is larger than the preset amplitude, it is indicated that the time belongs to the time period of the first reflected sound wave signal, the time is determined as the first echo starting time, at least part of the first reflected sound wave can be intercepted, and the noise can be avoided being intercepted.

S42: at the predetermined frequency f₀And sampling the acoustic echo signals after the first echo starting moment to obtain the first reflected acoustic wave signals containing K pulse acoustic wave signals.

By determining the number of the target echoes and the starting time of the first echo through the embodiment, the first reflected sound wave signal can be prevented from containing noise from the two aspects of the starting time and the number of the echoes, and the adverse effect of the noise on similarity comparison in subsequent steps is reduced. In addition, sampling is carried out based on the preset frequency, the sampling point can be ensured to be consistent with the frequency of the transmitted ranging sound wave signal, and invalid sampling is avoided.

S43: at the predetermined frequency f₀And sampling the acoustic echo signal after the first reflected acoustic wave signal to obtain the second reflected acoustic wave signal.

In the step, sampling is carried out based on the preset frequency, so that the sampling point can be ensured to be consistent with the frequency of the transmitted ranging sound wave signal, and invalid sampling is avoided. In addition, in the step, the acoustic echo signal after the first reflected acoustic wave signal is sampled, so that the first reflected acoustic wave signal is prevented from being repeatedly sampled, and the subsequent calculation amount of similarity comparison can be reduced.

Based on the solution provided by the foregoing embodiment, optionally, as shown in fig. 5, the foregoing step S42 includes:

s51: and determining the first time with the amplitude of 0 after the first echo starting time as a second echo starting time according to the acoustic echo signal.

S52: taking the starting moment of the second echo as a starting point and the preset frequency f₀Sampling the acoustic echo signal to obtain the first reflected acoustic wave signal comprising K pulsed acoustic wave signals.

In this step, the time at which the first amplitude value after the first echo starting time is 0 is determined as the second echo starting time, and then sampling is performed by using the second echo starting time as the starting time, so that an integer number of waveforms are guaranteed to be sampled, the difficulty of subsequent waveform processing can be reduced, and the processing efficiency is improved.

Based on the solution provided in the foregoing embodiment, optionally, as shown in fig. 6, before performing similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal, the method further includes:

s61: performing symbolization on the first reflected acoustic wave signal and the second reflected acoustic wave signal according to a reference amplitude value to obtain a first symbolized signal and a second symbolized signal.

In the step, the reflected sound wave signals are symbolized so as to reduce the processing complexity of cross correlation and effectively improve the processing efficiency. Optionally, the symbolization in this step may be implemented by hardware devices such as an analog comparator and a zero-crossing detection circuit.

Wherein, the step S34 includes:

s62: performing a cross-correlation operation on the first and second symbolized signals to determine a time period of the target reflected acoustic wave signal from the second reflected acoustic wave signal.

Through the scheme provided by the embodiment of the application, the reflected sound wave signals are symbolized, the data volume is obviously reduced, and the cross-correlation processing efficiency is improved.

Based on the solution provided by the foregoing embodiment, optionally, as shown in fig. 7, the foregoing step S61 includes:

s71: and recording the waveform which is greater than or equal to the reference amplitude as a first symbol value and recording the waveform which is smaller than the reference amplitude as a second symbol value according to the first reflected sound wave signal and the second reflected sound wave signal so as to obtain a first symbolized signal and a second symbolized signal.

The scheme provided by the embodiment of the application can be specifically realized by adopting an analog comparator and a Random Access Memory (RAM) for sampling and storing. Discrete time series f [ n ] is separated by introducing a symbolization operator sign { }]And s [ n ]]The original value range is-2^p-1To 2^p-1Becomes a value range of { -1,0, +1 }. Discrete time series f [ n ] after sampling and storing by RAM]And s [ n ]]The range of values further becomes 0 or 1 in the available 1-bit binary; binary "1" characterizes the symbolization operator sign { } with an output value of "+ 1", and binary "0" characterizes the symbolization operator sign { } with an output value of "-1". Due to discrete time series f [ n ]]And s [ n ]]The range of values may be represented by a 0 or 1 of a 1-bit binary, and thus storing the 0 or 1 of the 1-bit binary may be implemented using a RAM device having a bit width of 1 bit. In addition, the system architecture relating to the analog comparator and RAM will be described in detail laterThe above-mentioned processes are described.

The following provides a calculation rule of the symbolization operator sign { }, as shown in formula (1-2):

（1-2）

in the embodiment of the application, the role of the sign operator sign { } is to compare the value of c with the value of 0 and transform the value range of c into the value range of { -1,0, +1 }. If the value range of the acoustic echo simulation signal s (t) is [ Sm, Sn ], a symbolization operator sign { } is introduced to map the value range [ Sm, Sn ] of s (t) into the value range of { -1,0, +1}, so that the data volume can be effectively reduced, and the efficiency of similarity comparison is improved.

Based on the solution provided by the foregoing embodiment, as shown in fig. 8, before the foregoing step S34, optionally, the method further includes:

s81: performing sequence interpolation on the first reflected acoustic wave signal and the second reflected acoustic wave signal respectively based on a time sequence.

In this step, the sequence interpolation may be implemented by using a sequence interpolation algorithm. In the embodiment of the present application, the acoustic echo is specifically based on a plurality of discrete points arranged in time sequence, and the amount of data points in a unit time length can be increased by sequence interpolation, so as to achieve the effect of improving accuracy.

Wherein, the step S34 includes:

s82: and performing cross-correlation operation on the first reflected sound wave signal subjected to the sequence interpolation and the second reflected sound wave signal subjected to the sequence interpolation to determine the time period of the target reflected sound wave signal from the second reflected sound wave signal.

According to the scheme provided by the embodiment of the application, the cross-correlation operation is performed based on the interpolated reflected sound wave signals, and the accuracy of the cross-correlation operation is positively correlated with the quantity of data points in unit time, so that the accuracy of the cross-correlation operation can be effectively improved through data interpolation, and the determined time period of the target reflected sound wave signals is more accurate.

In order to solve the problems existing in the prior art, an embodiment of the present application further provides an acoustic ranging apparatus 90, as shown in fig. 9, including:

the sending module 91 sends a ranging sound wave signal to a target to be measured;

a receiving module 92, configured to receive an acoustic echo signal reflected by the target to be detected based on the ranging acoustic signal, where the acoustic echo signal includes a plurality of reflected acoustic signals based on a time sequence;

a first determining module 93, configured to determine a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo, where the second reflected acoustic wave signal includes a target reflected acoustic wave signal adjacent to the first reflected acoustic wave signal based on a time sequence;

a second determining module 94, configured to perform similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal, so as to determine a time period in which the target reflected acoustic wave signal is located from the second reflected acoustic wave signal;

a third determining module 95, configured to determine a distance between the target and the target to be measured according to an absolute delay between the first reflected acoustic wave signal and the target reflected acoustic wave signal, where the absolute delay is determined according to a time period of the first reflected acoustic wave signal in the acoustic echo signal and a time period of the target reflected acoustic wave signal in the acoustic echo signal.

The modules in the device provided by the embodiment of the present application may also implement the method steps provided by the method embodiment. Alternatively, the apparatus provided in the embodiment of the present application may further include other modules besides the modules described above, so as to implement the method steps provided in the foregoing method embodiment. The device provided by the embodiment of the application can achieve the technical effects achieved by the method embodiment.

In order to solve the problems existing in the prior art, an embodiment of the present application further provides an acoustic ranging system, as shown in fig. 10, including:

the transmitting transducer 101 is used for transmitting a ranging sound wave signal to a target to be measured;

the receiving transducer 102 is used for receiving an acoustic echo signal reflected by the target to be detected based on the ranging acoustic wave signal, wherein the acoustic echo signal comprises a plurality of reflected acoustic wave signals based on time sequence;

a comparator 103 communicatively coupled to the receiving transducer 102 for determining a first reflected acoustic wave signal and a second reflected acoustic wave signal from the acoustic echo, the second reflected acoustic wave signal comprising a target reflected acoustic wave signal chronologically adjacent to the first reflected acoustic wave signal;

a processor 104, communicatively connected to the transmitting transducer 101 and the comparator 103, for performing a similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal to determine a time period of the target reflected acoustic wave signal from the second reflected acoustic wave signal;

the processor 104 is further configured to determine a distance from the target to be measured according to an absolute delay between the first reflected acoustic wave signal and the target reflected acoustic wave signal, where the absolute delay is determined according to a time period of the first reflected acoustic wave signal in the acoustic echo signal and a time period of the target reflected acoustic wave signal in the acoustic echo signal.

The processor may be configured to send the ranging acoustic signal in the form of an electrical signal to the transmitting transducer, so as to instruct the transmitting transducer to convert the ranging acoustic signal in the form of an electrical signal into an acoustic signal and send the acoustic signal. In addition, the processor can also be used for setting parameters such as a preset amplitude value, a preset frequency and a preset phase of the ranging sound wave signal.

The system provided by the embodiment of the application can further comprise at least one RAM used for storing signals. Optionally, a zero-crossing detection circuit may be further included. As shown in fig. 11, for the convenience of understanding, the functions of the components in the system are explained by taking the signals in the above method embodiment as an example. The transmitting acoustic wave module may specifically include a transmitting transducer, where the s (t) input signal may be acquired by the receiving transducer and sent to the zero-crossing detection circuit in communication connection in a wired or wireless communication manner.

The acoustic echo analog signal s (t) passes through a zero-crossing detection circuit to obtain a measurement starting time Tt and a level edge jump mark. The function of a symbolization operator sign { } is realized by a simulation comparator through hardware, and after an acoustic echo simulation signal s (t) is symbolized by the simulation comparator, s (t) is converted into a time-continuous simulation signal sign { s (t) } with 2 discrete amplitudes (high level and low level).

When performing sampling, using a known transmitted acoustic parameter (fixed frequency f)₀Number of transmitted acoustic pulses N₀) Setting a fixed equal-interval sampling frequency f when the measurement start time Tt is known_sAnd K value, according to formula K f₀= N_s/ f_sSolving the number of sampling points N_sBased on the measurement start time Tt and the number of sampling points N_sK (1 < K < N) in the first reflected sound wave can be intercepted and separated from the sound echo₀K is a positive integer) pulse parts to form sign { f_K(t) } participates in the cross-correlation operation.

The RAM device is used for comparing sign { s (t) } and sign { f_K(t) performing time discrete sampling and storage to form a discrete time sequence sign { s [ n ]]} and sign { f_K[n]}. Wherein, a symbolized cross-correlation calculation formula is utilized:

using a discrete time series sign s n]} and sign { f_K[n]Calculating R_sf’[n₀]Corresponding n to the maximum time of the correlation peak₀Determined as the acoustic propagation delay. Ranging is then implemented based on acoustic propagation delay and acoustic propagation speed.

In the system provided in this embodiment, a simulation comparator is specifically applied to implement the function of the sign operator sign { }. For example, a symbolization operator sign { } function is realized in a hardware manner by using a simulation comparator which sets a reference level to 0V, an acoustic echo simulation signal s (t) is compared with the reference level 0V, and the acoustic echo simulation signal s (t) is transformed into a time-continuous simulation signal sign { s (t) } with only 3 discrete amplitudes.

Optionally, the analog comparator supports bipolar signal input, dual power rails supply power, the output range of the analog comparator { positive power rail level, 0V level, negative power rail level }, the analog comparator IN + is connected to the acoustic echo analog signal s (t), and the analog comparator IN-is connected to the reference level 0V. Then, the symbolization can be represented by the following formula (2-1):

（2-1）

optionally, in the system provided in this embodiment of the present application, an analog comparator with a specific binary level (high level, low level) output is applied to convert s (t) into a time-continuous analog signal sign { s (t) } with 2 discrete amplitudes, where the value range is { high level, low level }.

Optionally, the analog comparator applied IN the system provided IN the embodiment of the present application supports bipolar signal input and dual power rails for power supply, the output of the analog comparator is TTL level or CMOS level, the analog comparator IN + is connected to the acoustic echo analog signal s (t), and the analog comparator IN-is connected to the reference level 0V. Then the symbolization can be represented by the following formula (2-2):

（2-2）

the analog comparator in the system provided by the embodiment of the application realizes symbolization based on the reference level 0V, and a schematic diagram of symbolization is shown in fig. 12. And after the acoustic echo analog signal is input into the analog comparator, the analog comparator compares the acoustic echo analog signal with a reference level and outputs a signed acoustic echo signal containing high and low levels.

The zero crossing detection circuit in the system provided by the embodiment of the present application is used to identify the measurement start time Tt, i.e. the second echo start time described in the above method embodiment. The zero-crossing detection circuit is specifically used for selecting a certain zero-crossing point moment in the acoustic echo analog signal s (t) as the measurement starting moment Tt, and the zero-crossing detection circuit outputs level edge jump to represent the measurement starting moment Tt.

Optionally, the zero-crossing detection circuit is composed of an analog comparator C1, an analog comparator C2 and a flip-flop, the flip-flop is introduced to prevent the circuit from being affected by noise, and the zero-crossing detection circuit has the following functions: (1) the circuit is provided with a controllable enabling end; (2) the input end of the analog comparator C1 is respectively connected with s (t) and a comparator C1 threshold Q1; (3) the input ends of the analog comparator C2 respectively input s (t) and a comparator C2 threshold value 0V; (4) the output end of the analog comparator C1 is connected with a trigger; (5) the first zero crossing after the amplitude reaches the threshold Q1 of the comparator C1 is detected(s) (t), and the output level edge at the output of the analog comparator C2 jumps. In order to optimize the reliability of the cross-correlation result, the zero-crossing point time in the section with larger amplitude of s (t) is selected as possible as the measurement start time Tt, and in practical application, the threshold Q1 of the comparator C1 is set to be close to the maximum amplitude of s (t).

Alternatively, as shown in fig. 13, the function of the zero-cross detection circuit is described with reference to the drawings. Wherein, the input end IN + of the analog comparator C1 is connected with s (t), and the input end IN-is connected with the threshold Q1 of the comparator C1; the input end IN + of the analog comparator C2 is connected with the threshold value 0V of the comparator C2, and the input end IN-is connected with s (t); after the circuit is enabled, when the amplitude of s (t) is greater than the threshold Q1 of the comparator C1 at a certain time (point A), the output level of the analog comparator C1 is changed from low level to high level, a trigger is further triggered, the analog comparator C2 is further enabled, and at the moment the analog comparator C2 is enabled, because s (t) is greater than the threshold 0V of the comparator C2, the analog comparator C2 outputs low level; s (t) after the point A, moving to 0V (point B), and finally falling below the threshold value of the comparator C2 at the moment of 0V, the analog comparator C2 outputs high level to form level edge jump, and the low-high level jump at the output end of the analog comparator C2 can indicate the measurement starting moment Tt. (5) After all parameters of the acoustic measurement system are solidified, the amplitude, the phase and the frequency of the transmitted acoustic wave can be fixed in multiple measurements, so that the amplitude, the point A and the point B of the acoustic echo analog signal s (t) are approximately the same, and the zero-crossing detection circuit is ensured to successfully capture the point A and the zero-crossing point B.

The system provided by the embodiment of the application can be used for intercepting and separating the integer K (K is more than 1 and less than N) in the first reflected sound wave from the sound echo₀K is a positive integer) pulse parts to form sign { f_K(t) } participates in the cross-correlation operation. Specifically, sign { f } is formed_K(t) } the following two methods may be employed:

(1) firstly, separating out f (t) effective part in time domain s (t), then using analog comparator to make symbolic calculation on f (t) to obtain sign { f_K(t)};

(2) Firstly, s (t) is signed and calculated by a simulation comparator to obtain sign { s (t) }, and then sign { f } is separated from sign { s (t) }_K(t)}。

The above two methods are equivalent, and the following description is made in conjunction with method (2), as shown in FIG. 14. After the measurement start time Tt, K (1 < K < N) is selected₀K ∈ positive integer) value; after passing through a simulation comparator, an acoustic echo simulation signal s (t) forms sign { s (t) }; known transmitted acoustic parameters (fixed frequency f)₀Number of transmitted acoustic pulses N₀) It can be known that the acoustic echo and the transmitted acoustic wave have the same frequency f₀And number of pulses N₀(ii) a Knowing the start of measurement Tt, if the control system sets a fixed, equally spaced sampling frequency f_sUsing the formula K/f₀=N_s/f_sAt the determination of f_s、f₀K, the number of sampling points is N_s(ii) a With the variable N =0, the control system samples the frequency f at regular equal intervals from the start time Tt of the measurement_sSampling sign { s (t) }, storing each sampling point and recording the index N of the sampling point, wherein N is automatically increased by 1 when N is more than or equal to N_sStopping sampling sign { s (t) } and storing; when N is more than or equal to N_sThen, the integral K pulse parts in the first reflected sound wave are intercepted and separated from the sound echo to form sign { f_K(t) for subsequently performing a cross-correlation operation.

To further explain this scheme, an example of K =6 is described, as shown in fig. 15. Wherein, assume f₀=1MHz, if the sampling frequency is f at equal intervals_sK =6, available N, =10MHz_s= 600; when N =600, the sampling and storing are stopped, assuming that the variable N = 0.

Typically, RAM devices are unable to sample a time-continuous analog signal because the range of time-continuous analog signal values does not satisfy the RAM data bus signal level input conditions. In the system provided by the embodiment of the application, a RAM device is used for pairing sign { s (t) } and sign { f_K(t) time discrete sampling and storing. In order to solve the problem that the RAM cannot be applied due to the threshold range problem, the echo signal symbolization is realized through a symbolization operator in the application so as to meet the requirement of RAM level inputEntering the condition.

In the system provided in the embodiment of the present application, the RAM device includes the following configurations:

(1) input port: the clock frequency fram;

(2) input/output ports: a data bus;

(3) input port: an address bus; a RAM can be selected, and the input condition of the data bus signal level is TTL/CMOS.

In the embodiment of the application, sign { s (t) } and sign { f are formed after symbolic operator sign { }isintroduced and the symbolic operator sign { } functional processing is realized by using a simulation comparator_K(t) } is a time-continuous, analog signal having 2 discrete amplitudes (high, low). One example is: sign { s (t) } and sign { f_K(t) } meets TTL or COMS standard and meets the signal level input condition of RAM data bus.

To enable signals sign { s (t) } and sign { f_K(t) can be input into the data bus of the RAM, and the control system must also be able to read sign { s (t) } and sign { f } from the RAM_K(t) } the data formed must be introduced into a controllable switch, a typical example being an "SPDT (single pole double throw) analog switch", which is connected in such a way that: the COM end (public end) is connected with the RAM data bus; the NC terminal (normally closed terminal) is connected with signals sign { s (t) } and sign { f }_K(t), the NO end (normally open end) is connected with the control system.

Optionally, in order to further improve the performance of the system provided in the embodiment of the present application, a device with a high clock frequency is preferred, and generally, the clock frequency of the RAM device can reach more than 500MHz, and the access time of the high-performance device is less than 100 ps. Furthermore, multiple RAMs can be selected to realize interleaved sampling, the density of sequence sampling points is further improved, and the type of the data bus with the bit width of 1bit is preferred. In addition, it is preferable to use an address self-increment RAM, in which data storage is realized only by controlling the RAM clock, or a circuit is designed to realize the address self-increment function when the RAM clock is input, and the circuit can be realized by using a mature circuit such as a serial shift register, and the purpose of the technology is to give and switch the RAM address without a control system.

Optional, RAM, SPDT switch blocksThe resultant RAM sampling and storage circuit is shown in fig. 15, in which, with the configuration of fig. 15, the clock frequency fram is given by the control system D; the bit width of the data bus can be selected to be 1 bit; the address bus is given by the E end of the control system; signals sign { s (t) } and sign { f_K(t) is input from the A terminal; RAM device to signal sign { s (t) } and sign { f_K(t) and the steps and flow for time discrete sampling and storing are as follows:

(1) the control system controls the B end and controls the SPDT switch to be switched into the communication between the NC end and the COM end;

(2) setting the RAM to be in a writing state, and giving a fragm clock to a D end by a control system;

(3) the control system gives an RAM address at the E end, is driven by the fram clock and is at t_xTime of day, RAM reads analog signal sign { s (t) with 2 discrete amplitudes (high level, low level) continuously in time_x) And sign { f }_K(t) } analog TTL/COMS levels that exist in only two states, high and low; if the level is high, the RAM value is binary "1", and if the level is low, the RAM value is binary "0". At this point, a sampling process is completed, and sign { s (t) }_x) And sign { f }_K(t_x) Converting into a time-discrete value sign { s [ n ] having two discrete values (1, 0)_x]And sign { f }_K(n_x) Finish sign s [ n ] for the sub-sampled value at the same time_x]And sign { f }_K(n_x) The storage process of };

(4) in the example process (2) to (3), at each specific time (determined by the control system and the fram clock), the pair sign { s (t) is completed according to the fram clock frequency_x) And sign { f }_K(t) sampling to obtain a time-discrete sequence of values sign s n with two discrete values (1, 0)]And sign { f }_K[n]}。

By means of the above-described steps, a time-discrete sequence of values sign { s [ n ] with two discrete values (1, 0)]And sign { f }_K[n]It has been stored in RAM at a known address, and if the control system needs to read sign { s [ n ]]And sign { f }_K[n]Numerical values, procedures and flow are as follows:

(1) the control system controls the terminal B and controls the SPDT switch to be switched into a state that the terminal NO is communicated with the terminal COM;

(2) setting the RAM to be in a reading state, and giving a fram clock to a control system at a D end;

(3) the control system gives RAM address at E end, and under the drive of fram clock, the control system can obtain the value of this given RAM address at C end, i.e. sign { s [ n ]]And sign { f }_K[n]A numerical value;

(4) example schemes (2) - (3) are repeated, and the sequence sign { s [ n ] is read in order]And sign { f }_K[n]All values.

In the system provided by the embodiment of the application, the cross-correlation formula of the discrete time series f [ n ] and g [ n ] is detailed in the formula (1-1) in the above method example. In this embodiment, after the echo signal is symbolically simplified, the cross-correlation calculation may be performed by applying the following expression (2-3).

（2-3）

Sign { g [ n ] } represents a sequence of the g [ n ] sequence after symbolization calculation;

sign { f [ n ] } represents the sequence of the f [ n ] sequence after symbolization calculation;

n is a numerical sequence time index;

n₀indexing the numerical value sequence delay;

n is the total length of the numerical sequence;

a' is a coefficient, related to N;

R’_gf[n₀]and R_gf[n₀]The following relationships exist:

(1) sign { f [ n ] } and sign { g [ n ] } preserve the sequence f [ n ] and g [ n ] properties;

（2）R’_gf[n₀]and R_gf[n₀]The occurrence positions of the correlation peaks are consistent, namely the acoustic propagation delay is unchanged;

(3) after symbolic calculation, under the condition of high signal-to-noise ratio, the value A 'is less than the value A, and under the condition of low signal-to-noise ratio, the value A' is approximately equal to the value A.

Under high signal-to-noise ratio conditions, the signed cross-correlation calculation results are shown in fig. 16 a. Under low signal-to-noise ratio conditions, the signed cross-correlation calculation results are shown in fig. 16 b. As can be seen from fig. 16a and 16b, the scheme provided by the embodiment of the present application can achieve better effects under high and low snr conditions.

In cross-correlation calculation, a multiplication part consumes a large amount of calculation resources, and a sequence sign { s [ n ] is proposed]And the sequence sign { f }_K[n]Multiplication is directly translated into a bit binary exclusive nor (XNOR) calculation:

sign{s[n]sequence and sign f_K[n]The value ranges of the sequences are { +1, -1}, and sign { s [ n ] as described in the above embodiments]Sequence and sign f_K[n]The sequence is stored in RAM as a binary 0 or 1, so: sign { s [ n ]]Sequence and sign f_K[n]When the sequence takes the value of +1, the binary system 0 is used for representing the sequence; sign { s [ n ]]Sequence and sign f_K[n]When the value of the sequence is = -1, the sequence is represented by binary 1. sign { s [ n ]]Sequence and sign f_K[n]Multiplication operation of the sequence is shown in table 1;

TABLE 1 sign { s [ n ]]Sequence and sign f_K[n]The sequence is multiplied

Wherein sign { s [ n ]]And sign { f }_K[n]The values are the same, sign { s [ n ]]}×sign{f_K[n]The value +1 is taken, represented by binary 1, sign { s [ n ]]And sign { f }_K[n]Different, sign { s [ n ]]}×sign{f_K[n]The value is-1, which is represented by binary 0.

Optionally, sign { s [ n ] for the sequence]And sign { f }_K[n]The interpolation can further adopt a sequence interpolation technology in a digital signal processing means, and the interpolation operation does not influence the sound propagation delay as can be known from the mathematical principle. Before the cross-correlation operation, integer-multiple interpolation is performed. An example is to complement the sequence by Q0 s every M samples.

The embodiment of the application realizes the function of the symbolic operator sign { } by introducing the symbolic operator sign { } and utilizing a simulation comparator and identifies and measures a system by a zero-crossing detection systemAt the start time Tt, the first reflected sound wave is separated to form sign { f_K(t) participating in cross-correlation, using RAM device to pair sign { s (t) } and sign { f }_K(t) } carries out time discrete sampling and storage, simplifies cross-correlation calculation through a symbolic operator sign { } and further improves the density of sequence sampling points through a sequence interpolation technology, and the like, and provides a realizable sound propagation delay measurement scheme with remarkable effect together, so that distance measurement can be realized according to the determined sound propagation delay and sound propagation speed, the accuracy and efficiency of distance measurement are effectively improved, and the method can be widely applied to various scenes and is suitable for underwater and dark scenes with insufficient light.

The modules in the system provided by the embodiment of the present application may also implement the method steps provided by the method embodiment. Alternatively, the apparatus provided in the embodiment of the present application may further include other modules besides the modules described above, so as to implement the method steps provided in the foregoing method embodiment. The device provided by the embodiment of the application can achieve the technical effects achieved by the method embodiment.

Preferably, an embodiment of the present invention further provides an electronic device, which includes a processor, a memory, and a computer program stored in the memory and capable of running on the processor, where the computer program, when executed by the processor, implements each process of the foregoing embodiment of the acoustic ranging method, and can achieve the same technical effect, and in order to avoid repetition, details are not repeated here.

The embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements each process of the above-mentioned embodiment of the acoustic ranging method, and can achieve the same technical effect, and in order to avoid repetition, details are not repeated here. The computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. An acoustic ranging method, comprising:

sending a ranging sound wave signal to a target to be measured;

2. The method of claim 1, wherein the ranging sonic signal includes a predetermined frequency f₀ToSet number N₀A pulsed acoustic signal, said f₀Is a positive number, N₀Is an integer greater than 1;

3. Method according to claim 2, characterized in that at said predetermined frequency f₀Sampling the acoustic echo signal after the first echo start time to obtain the first reflected acoustic wave signal including K pulsed acoustic wave signals, comprising:

4. The method of claim 1, wherein prior to performing a similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal, further comprising:

5. The method of claim 4, wherein performing the symbolization of the first reflected acoustic wave signal and the second reflected acoustic wave signal according to a reference amplitude value to obtain a first symbolized signal and a second symbolized signal, comprises:

6. The method of claim 1, wherein prior to performing a similarity comparison on the first reflected acoustic wave signal and the second reflected acoustic wave signal, further comprising:

7. An acoustic ranging device, comprising:

8. An acoustic ranging system, comprising:

9. An electronic device, comprising: memory, processor and computer program stored on the memory and executable on the processor, which computer program, when executed by the processor, carries out the steps of the method according to any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, which computer program, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 6.