KR102057271B1 - Apparatus and method for augmenting audio signals - Google Patents

Abstract

According to one embodiment of the present invention, provided is an apparatus for extending an acoustic signal which comprises: an acoustic signal reception unit receiving an acoustic signal; a transformation unit two-dimensionally transforming the received acoustic signal with respect to a time-frequency domain; an extraction unit extracting a region including a target by applying a first window with respect to the two-dimensionally transformed acoustic signal; a scanning unit scanning the extracted region using a second window rather than a first window to extract a plurality of scan regions; and an acquisition unit acquiring target data and non-target data from the plurality of scan regions.

Description

Acoustic signal expansion device and method {APPARATUS AND METHOD FOR AUGMENTING AUDIO SIGNALS}

The present invention relates to an apparatus and method for extending an acoustic signal. More specifically, the present invention relates to an apparatus and method for obtaining more sonar data by expanding sonar signals reflected from a target.

Sonar (SONAR: Sound Navigation and Ranging) is divided into active sonar and passive sonar, depending on whether a radiation signal is generated.

An active sonar system refers to a system that detects an underwater target by emitting an acoustic signal, which is an acoustic signal underwater, and then receiving an acoustic signal (including a target signal) that is reflected back from the target.

One of the major difficulties in the study of detecting and identifying targets using active sonar is that it is difficult to experiment with the actual underwater data which is essential for verifying the adequacy of the characteristic analysis method and the applied identification technique of the received target signal. In other words, the absence of an active sonar or target signal considering the actual aquatic environment has a great influence on the conduct of research on target detection and identification techniques. In addition, unlike passive target recognition, in which long-term tonal components are scaled into a database and mainly used as feature information, active target detection and identification using only short-time echo sound signals require a large amount to obtain a verified and stable identification performance. The actual maritime experimental data is essential. In particular, the active target detection and identification technology in the underwater environment has a complex characteristic in which the characteristics of the underwater acoustic signal are changed due to the environmental variable of underwater, and due to the difficulty of collecting marine data, the synthesized signal is mainly used in advanced countries. The situation is dependent on research through small-scale tank experiments.

Korea Patent Registration No. 10-1677137 (November 11, 2016 registration)

The problem to be solved by the present invention is to extend the acoustic signal in order to overcome the difficulties of collecting the actual maritime data, which is essential for applying artificial intelligence to active sonar detection and identification, and to secure a large amount of real maritime experimental data. It is to provide an apparatus and method for.

However, the problem to be solved by the present invention is not limited to the above-mentioned, it is not mentioned but includes the purpose that can be clearly understood by those skilled in the art from the following description. can do.

An acoustic signal extension apparatus according to an embodiment of the present invention, the sound signal receiving unit for receiving the sound signal; A converter which two-dimensionally converts the received sound signal with respect to a time-frequency domain; An extraction unit configured to extract a region including a target by applying a first window to the two-dimensional converted sound signal; A scanning unit which extracts a plurality of scan areas by scanning the extracted area using a second window smaller than the first window; And an acquisition unit for acquiring target data and non-target data from the plurality of scan areas.

In addition, the transform unit is two-dimensional to the sound signal in the time-frequency domain using at least one of a Fourier transform, a wavelet transform, and the Wigner-Ville distribution. I can convert it.

The extractor may extract a region including the target by applying the first window having a larger size than the target with respect to the target in the 2D converted sound signal.

The scanning unit may extract the plurality of scanning areas by scanning the area including the target from left to right and top to bottom using the second window.

The number of the plurality of scanning regions to be extracted may be determined according to the size of the second window and the overlap size of the second window.

In addition, the acoustic signal may be a sonar signal reflected from the target.

Underwater target detection method according to an embodiment of the present invention, receiving the acoustic signal; Two-dimensionally transforming the received acoustic signal with respect to a time-frequency domain; Extracting an area including a target by applying a first window to the two-dimensional transformed sound signal; Extracting a plurality of scan areas by scanning the extracted area using a second window smaller than the first window; And obtaining target data and non-target data from the plurality of scan areas.

The two-dimensional transformation may include performing a time-frequency domain on the sound signal using at least one of a Fourier Transform, a Wavelet Transform, and a Wigner-Ville Distribution. It may include the step of two-dimensional transformation for.

The extracting the region including the target may include extracting the region including the target by applying the first window having a larger size than the target with respect to the target in the two-dimensional converted sound signal. It may include.

The extracting of the plurality of scan areas may include extracting the plurality of scanning areas by scanning left to right and top to bottom using the second window with respect to the area including the target. Can be.

The number of the plurality of scanning regions to be extracted may be determined according to the size of the second window and the overlap size of the second window.

In addition, the acoustic signal may be a sonar signal reflected from the target.

In addition, the computer-readable recording medium storing the program according to an embodiment of the present invention, when the program is executed by a processor, receiving a sound signal; Two-dimensionally transforming the received acoustic signal with respect to a time-frequency domain; Extracting an area including a target by applying a first window to the two-dimensional transformed sound signal; Extracting a plurality of scan areas by scanning the extracted area using a second window smaller than the first window; And acquiring target data and non-target data from the plurality of scan areas.

According to an embodiment of the present invention, in addition, according to an embodiment of the present invention, an area including a target is extracted by applying a first window to a two-dimensional transformed sound signal, Through the configuration of scanning with a small second window to extract a plurality of scan areas, and obtaining target data and non-target data from the plurality of scan areas, the difficulty of collecting actual sea data is overcome and a large amount of actual Maritime experiment data can be secured.

According to an embodiment of the present invention, the amount of data that can be acquired can be adjusted according to the size of the second window used for scanning and the overlap size of the second window when scanning.

In addition, in order to apply artificial intelligence technology including the latest deep learning technology, a large amount of actual marine experiment data can be obtained.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a functional block diagram of an apparatus for extending an acoustic signal according to an embodiment of the present invention.
2 is a flowchart of a method for extending an acoustic signal according to an embodiment of the present invention.
3 is a graph showing the magnitude of a sound signal received by the sound signal receiver according to an embodiment of the present invention on a time axis.
FIG. 4 is a diagram illustrating an acoustic signal two-dimensionally transformed in a time-frequency domain by a converter of an apparatus for extending an acoustic signal according to an embodiment of the present invention.
FIG. 5 illustrates that an extracting unit of an apparatus for expanding an acoustic signal according to an embodiment of the present invention applies a first window to extract an area including a target, and the scanning unit extracts a plurality of scan areas using a second window. It is a figure which illustrates that.
6 is a diagram illustrating an apparatus for expanding an acoustic signal according to an embodiment of the present invention to obtain target data and non-target data from a plurality of scan areas.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms, only the embodiments are to make the disclosure of the present invention complete, and those skilled in the art to which the present invention pertains. It is provided to fully inform the scope of the invention, and the scope of the invention is defined only by the claims.

In describing the embodiments of the present invention, detailed descriptions of well-known functions or configurations will be omitted unless they are actually necessary in describing the embodiments of the present invention. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the contents throughout the specification.

Used below '… Wealth, The term 'herein' refers to a unit for processing at least one function or operation, which may be implemented by hardware or software, or a combination of hardware and software.

1 is a functional block diagram of an acoustic signal expansion apparatus according to an embodiment of the present invention, Figure 2 is a flowchart of a sound signal expansion method according to an embodiment of the present invention.

The acoustic signal expansion device of the present invention may be one component of an active sonar system, or as an independent device of the active sonar system, the radiation signal emitted by the active sonar system underwater to receive and receive the acoustic signal returned from the target and received. It may mean a device for obtaining a plurality of target and non-target data by extending the sound signal.

Referring to FIG. 1, an acoustic signal extension apparatus 1 according to an exemplary embodiment of the present invention may include a sound signal receiver 100 that receives a sound signal, and a two-dimensional conversion of the received sound signal with respect to a time-frequency domain. The extraction unit 300 extracts an area including a target by applying a first window to the two-dimensional transformed sound signal, and scans the extracted area using a second window smaller than the first window. a scanning unit 400 extracting a plurality of scan areas by scanning; And an acquisition unit 500 for acquiring target data and non-target data from the plurality of scan areas.

The sound signal receiver 100 may receive a sound signal (S210). The acoustic signal received by the acoustic signal receiver 100 may be an acoustic signal including a target signal in which the radiation signal radiated by the active sonar system is reflected by the underwater target.

At this time, the radiation signal emitted by the active sonar system may include a continuous wave (CW) signal, and / or a linear frequency modulation (LFM) signal. In general, the CW signal is used to estimate the speed of the underwater target using the Doppler effect, and the LFM signal can be used to detect and estimate the distance of the underwater target.

If the LFM signal is emitted as a radiation signal, the sonar system may emit the radiation signal S (t) according to Equation 1 to the underwater target.

According to Equation 1, the phase of the radiation signal S (t) is 2π (at ² + f ₀ t + c), and the instantaneous frequency of the radiation signal S (t) is the phase of the radiation signal S (t). It may be 2πt + f ₀ [Hz] which is a derivative value of. Accordingly, the radiation signal S (t) is an LFM signal having a start frequency of f ₀ and a frequency change rate (Chirp Rate) of 2a, and may have a characteristic that the instantaneous frequency changes linearly with time.

In addition, the acoustic signal receiver 100 may receive an acoustic signal including the target signal in which the above-described radiation signal is directed (reflected) by the underwater target.

Hereinafter, a sound signal received by the sound signal receiver 100 will be described with reference to FIG. 3.

3 is a graph showing a magnitude of a sound signal received by a sound signal receiver according to an embodiment of the present invention on a time axis.

Referring to FIG. 3, the sound signal receiver 100 may receive a sound signal continuously from a time point at which a radiation signal is emitted by an active sonar system. In this case, the radiated radiation signal may be reflected by the underwater target, and the acoustic signal receiver 100 may receive an acoustic signal including the target signal reflected by the underwater target.

In the case of Figure 3, it can be seen that the sound signal received by the sound signal receiving unit 100 rapidly increases after 0.6 seconds and then decreases again. This may mean that the target signal reflected by the underwater target is included in the acoustic signal at that time.

On the other hand, the sound signal receiving unit 100 may continuously receive a signal within ± 0.2dB since the time when the sound signal is received. This is because the acoustic signal includes a reverberation signal scattered or reflected by a scatterer in which a radiation signal is present in water and a background noise signal present in water.

Therefore, in order to obtain information about the underwater target, it is necessary to accurately detect the target signal present in the acoustic signal received by the acoustic signal receiver 100.

In order to detect a target signal in an acoustic signal, a matched filter based on a fast Fourier transform can be used. Specifically, the target signal can be detected by continuously correlating the received acoustic signal with the radiation signal as a reference signal.

However, the method of using the matched filter may lower the accuracy of the target signal detection in an environment where the influence of the reverberation signal and the background noise signal in the acoustic signal is large. In addition, when the LFM signal is radiated as a radiating signal, as the frequency band of the radiated LFM signal increases, not only frequency shift due to the Doppler effect but also slope mismatch may occur. As a result, a correlation loss may occur in the matched filter, resulting in poor detection performance for underwater targets. In addition, non-targets or clutters that exhibit characteristics similar to those of underwater targets or have sizes above thresholds may be mistaken for underwater targets.

To solve this problem, the acoustic signal extension apparatus according to an embodiment of the present invention can detect a target signal by two-dimensionally converting the acoustic signal in the time-frequency domain.

In detail, the converter 300 may two-dimensionally convert the sound signal received by the sound signal receiver 100 in the time-frequency domain (S220). Hereinafter, referring to FIG. 4, the two-dimensionally transformed acoustic signal I ₁ in the time-frequency domain will be described.

4 is a diagram illustrating an acoustic signal two-dimensionally transformed in the time-frequency domain by the converter according to an embodiment of the present invention.

In order to confirm the change in the frequency component of the sound signal over time, the converter 300 may two-dimensionally convert the sound signal received by the sound signal receiver 100 with respect to the time-frequency domain. The converter 300 according to an exemplary embodiment may obtain a spectrogram by performing fast Fourier transform on the sound signal, thereby performing two-dimensional conversion of the sound signal in the time-frequency domain. In addition, the transform unit 300 according to another embodiment may apply a wavelet transform to a sound signal to obtain a scaleogram, thereby converting the sound signal to a two-dimensional time domain. . The converting unit 300 according to another embodiment uses a Wigner-Ville Distribution for Fourier transforming auto correlation of an acoustic signal, thereby converting the acoustic signal into two time-frequency domains. Dimension can be converted.

4 illustrates a result of two-dimensional transformation of the acoustic signal of FIG. 3 with respect to the time-frequency domain according to any one of the above-described methods. 4, it can be seen that the instantaneous frequency of the two-dimensionally converted acoustic signal I ₁ changes linearly with time at a point immediately after 0.6 seconds when the magnitude of the acoustic signal rapidly increases and decreases in FIG. 3. Can be. As such, the target signal present in the acoustic signal I ₁ , which is two-dimensionally transformed with respect to the time-frequency region, may be identified as an area having a specific shape.

FIG. 5 is a diagram illustrating an extracting unit of an apparatus for expanding an acoustic signal according to an embodiment of the present invention, extracting an area including a target by applying a first window, and extracting a plurality of scan areas by using the second window; It is a figure which illustrates that.

The extractor 300 may extract a region including the target by applying the first window to the acoustic signal that has been two-dimensionally converted by the converter 200 (S230).

As illustrated in FIG. 5, the extractor 300 may extract a region including the target by applying a first window 310 having a larger size than the target based on the target in the 2D converted sound signal.

The scanning unit 400 extracts a plurality of scan areas by scanning the area including the target extracted by the extractor 300 using the second window 320 smaller than the first window 310. Can be (S240). In one embodiment, the scanning unit 400 may extract a plurality of scanning areas by scanning from left to right and top to bottom using the second window 320 for the area including the target. In another embodiment, the scanning unit 400 may extract a plurality of scanning areas by scanning the area including the target from the right to the left and the top to the bottom or the bottom to the top using the second window 320. . However, the direction or method in which the scanning unit 400 scans the area including the target by using the second window 320 is not limited thereto.

When the scanning unit 400 scans the area including the target by using the second window 320, the size of the second window 320 may be arbitrarily determined.

In addition, according to the size of the second window 320 and the size of the second window 320 overlap each other when the scanning unit 400 scans the area including the target using the second window 320. The number of the plurality of scanning regions to be extracted is determined. For example, if the size of the second window 320 is small or there are many overlaps, more scanning regions can be extracted. On the contrary, if the size of the second window 320 is large or the overlaps are small, a relatively small number of scanning areas can be extracted. The scanning area is extracted.

6 is a diagram illustrating an apparatus for expanding an acoustic signal according to an embodiment of the present invention to obtain target data and non-target data from a plurality of scan areas.

As shown in FIG. 6, the acquirer 500 scans the area including the target by using the second window 320 smaller than the first window 310 to extract a plurality of scan areas. 66 target and non-target data may be obtained from one region including the target (S250). In an exemplary embodiment, the acquirer 500 scans each of the plurality of scan regions extracted by using the second window 320 smaller than the first window 310 with respect to the region including the target, as the target data or the ratio. Target data can be obtained. In another embodiment, the acquirer 500 may acquire the target data or the non-target data by flipping each of the plurality of scan areas horizontally or vertically. In another embodiment, the acquirer 500 may acquire target data or non-target data by rotating each of the plurality of scan areas. In another embodiment, the acquirer 500 may acquire target data or non-target data by enlarging or reducing the size of each of the plurality of scan areas. In another embodiment, the acquirer 500 may acquire target data or non-target data by randomly sampling a portion of each of the plurality of scan areas and then adjusting the size to the size of the original scan area. Can be. The method of acquiring target data and non-target data from a plurality of scan areas scanned by using the second window 320 with respect to the area including the target may be performed by combining one or more of the above-described methods. However, it is not limited thereto. As a result, it is possible to obtain a large amount of actual maritime experiment data required to apply artificial intelligence technology including the latest deep learning technology.

Depending on the scanning position of the second window 320, the scan area scanned by the second window may have no target, some may exist, or may include the entire target. In addition, the plurality of scan areas that are extended and extracted through the scanning of the scanning unit 400 may be classified as target data or non-target data.

The above-described acoustic signal extension apparatus and method extract a region including a target by applying a first window to a two-dimensional transformed acoustic signal, scan the extracted region with a second window smaller than the first window, By extracting the scan area of the, and obtaining the target data and non-target data from the plurality of scan areas, it is possible to overcome the difficulty of collecting the actual sea data, and to secure a large amount of real sea experiment data stably. As a result, it is possible to obtain a large amount of actual maritime experiment data required to apply artificial intelligence technology including the latest deep learning technology.

Combinations of each block of the block diagrams and each step of the flowcharts attached herein may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment such that instructions executed through the processor of the computer or other programmable data processing equipment may be used in each block or flowchart of the block diagram. It will create means for performing the functions described in each step. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in each block or flowchart of each step of the block diagram. Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions that perform processing equipment may also provide steps for performing the functions described in each block of the block diagram and in each step of the flowchart.

In addition, each block or step may represent a portion of a module, segment or code that includes one or more executable instructions for executing a specified logical function (s). It should also be noted that in some alternative embodiments, the functions noted in the blocks or steps may occur out of order. For example, the two blocks or steps shown in succession may in fact be executed substantially concurrently or the blocks or steps may sometimes be performed in the reverse order, depending on the functionality involved.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential quality of the present invention. Accordingly, the embodiments disclosed herein are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas that fall within the scope of equivalents should be construed as being included in the scope of the present invention.

100: sound signal receiving unit
200: converter
300: extraction unit
400: scanning unit
500: Acquisition

Claims (13)

An acoustic signal receiver for receiving an acoustic signal;
A converter which two-dimensionally converts the received sound signal with respect to a time-frequency domain;
An extraction unit configured to extract a region including a target by applying a first window to the two-dimensional converted sound signal;
A scanning unit which extracts a plurality of scan areas by scanning the extracted area using a second window smaller than the first window; And
And an acquirer configured to acquire target data and non-target data from the plurality of scan areas.
Device for extending the acoustic signal. The method of claim 1,
The conversion unit,
Two-dimensional transformation of the acoustic signal with respect to the time-frequency domain using at least one of a Fourier Transform, a Wavelet Transform, and a Wigner-Ville Distribution.
Device for extending the acoustic signal. The method of claim 1,
The extraction unit,
Extracting an area including the target by applying the first window having a larger size than the target with respect to the target in the two-dimensional converted acoustic signal
Device for extending the acoustic signal. The method of claim 1,
The scanning unit,
Extracting the plurality of scanning regions by scanning from left to right and top to bottom using the second window for the region containing the target;
Device for extending the acoustic signal. The method of claim 4, wherein
The number of the plurality of scanning regions to be extracted is determined according to the size of the second window and the overlap size of the second window.
Device for extending the acoustic signal. The method of claim 1,
The acoustic signal is a sonar signal reflected from the target.
Device for extending the acoustic signal. Receiving an acoustic signal;
Two-dimensionally transforming the received acoustic signal with respect to a time-frequency domain;
Extracting an area including a target by applying a first window to the two-dimensional transformed sound signal;
Extracting a plurality of scan areas by scanning the extracted area using a second window smaller than the first window; And
Obtaining target data and non-target data from the plurality of scan areas.
How to extend the acoustic signal. The method of claim 7, wherein
The two-dimensional transformation,
Two-dimensionally transforming the acoustic signal with respect to the time-frequency domain using at least one of a Fourier Transform, a Wavelet Transform, and a Wigner-Ville Distribution.
How to extend the acoustic signal. The method of claim 7, wherein
Extracting a region containing the target,
Extracting an area including the target by applying the first window having a larger size than the target around the target in the two-dimensional converted acoustic signal;
How to extend the acoustic signal. The method of claim 7, wherein
Extracting the plurality of scan areas may include:
Extracting the plurality of scanning regions by scanning from left to right and top to bottom using the second window for the region containing the target.
How to extend the acoustic signal. The method of claim 10,
The number of the plurality of scanning regions to be extracted is determined according to the size of the second window and the overlap size of the second window.
How to extend the acoustic signal. The method of claim 7, wherein
The acoustic signal is a sonar signal reflected from the target.
How to extend the acoustic signal. Receiving an acoustic signal;
Two-dimensionally transforming the received acoustic signal with respect to a time-frequency domain;
Extracting an area including a target by applying a first window to the two-dimensional transformed sound signal;
Extracting a plurality of scan areas by scanning the extracted area using a second window smaller than the first window; And
A computer readable recording medium having stored thereon a program for performing a method of expanding an acoustic signal comprising obtaining target data and non-target data from the plurality of scan areas.

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