KR20210070640A - Apparatus and method for detecting objects using acoustic signals - Google Patents

Abstract

According to an embodiment of the present invention, provided is an apparatus for detecting an object using an acoustic signal that includes an acoustic sensor for detecting an externally generated acoustic signal; an acoustic signal conversion part for converting the detected acoustic signal into a spectrum signal in a frequency region; an operation part for calculating a magnitude value and the phase value of the spectrum signal, and calculating the sum of a magnitude value change amount and a phase value change amount according to time change; and a determination part for determining that the object approaches when the number of times the sum value exceeds the preset reference value is greater than or equal to the preset reference number in succession. It is possible to accurately detect whether the object is approaching.

Description

Apparatus and method for detecting objects using acoustic signals

One embodiment of the present invention relates to an apparatus and method for detecting an object using an acoustic signal, and more particularly, to an apparatus and method for detecting an object using an acoustic signal capable of detecting whether an object approaches by analyzing the acoustic signal.

In acoustic signal detection, onset refers to a starting point at which an increase in amplitude occurs when one section in which the amplitude of an acoustic signal changes is observed. The detection performance of an object using an acoustic signal depends on how quickly and accurately this section is detected. Attack refers to a section in which the amplitude of the sound signal increases from the peak point, and decay refers to a section in which the amplitude decreases from the peak point in the sound signal.

As a method of detecting the approach of an object using an existing acoustic signal, a method of detecting using only the magnitude of such a spectrum signal is used. However, in the case of the existing method, there is a problem that the difference in detection performance is very large depending on the level of ambient noise. In addition, since the conventional method detects an object using only the size of the spectrum, problems in detection speed and accuracy may occur.

An object of the present invention is to provide an apparatus and method for detecting an object using an acoustic signal capable of quickly and accurately detecting whether an object is approaching by analyzing the acoustic signal.

Another object of the present invention is to provide an apparatus and method for detecting an object using an acoustic signal capable of minimizing the influence of ambient noise.

According to an embodiment of the present invention, a sound sensor for detecting an external sound signal; an acoustic signal converter converting the sensed acoustic signal into a spectrum signal in a frequency domain; an operation unit for calculating the magnitude value and the phase value of the spectrum signal, and calculating a sum of the magnitude value change amount and the phase value change amount according to time change; and a determination unit that determines that the object approaches when the number of times the sum value exceeds the preset reference value is greater than or equal to the preset reference number in succession.

The calculator may include: a first processor configured to calculate a first section in which a magnitude value between consecutive frames increases by using the spectrum signal, and to calculate a first parameter obtained by summing changes in magnitude values in the first section; and calculating a second section in which the magnitude and phase values between consecutive frames are increased by using the spectrum signal, and calculating a second parameter obtained by summing the Euclidean distance values of the magnitude and phase values between frames in the second section A second processor may be included.

The calculator may calculate the sum value by summing the first parameter and the second parameter.

The calculation unit may calculate the sum value by giving weights to the first parameter and the second parameter, respectively.

It may further include a notification unit for outputting a notification signal under the control of the determination unit.

According to an embodiment of the present invention, the sound sensor detecting an external sound signal; converting the sensed sound signal into a spectrum signal in a frequency domain; calculating a magnitude value and a phase value of the spectrum signal, and calculating a sum of the magnitude value change amount and the phase value change amount according to time change; and determining that the object approaches when the number of times the sum value exceeds the preset reference value is greater than or equal to the preset reference number in succession.

In the calculating of the sum value, a first section in which the magnitude value between consecutive frames is increased by using the spectrum signal is calculated, and a first parameter obtained by summing changes in the magnitude value in the first section is calculated. step; and calculating a second section in which the magnitude and phase values between consecutive frames are increased by using the spectrum signal, and calculating a second parameter obtained by summing the Euclidean distance values of the magnitude and phase values between frames in the second section may include the step of

The calculating of the sum value may include calculating the sum value by summing the first parameter and the second parameter.

The calculating of the sum value may include calculating the sum value by giving weights to the first parameter and the second parameter, respectively.

The method may further include outputting a notification signal when it is determined that the object approaches.

An apparatus and method for detecting an object using an acoustic signal according to the present invention can detect whether an object approaches quickly and accurately by analyzing the acoustic signal.

In addition, it is possible to detect illegal approach and intrusion of an unmanned aerial vehicle by outputting a warning sound whether an object is approaching.

In addition, it is possible to quickly determine whether a vehicle, a bicycle, an electric quick board, or the like is approaching and notify the pedestrian.

1 is a block diagram of an object detecting apparatus using an acoustic signal according to an embodiment of the present invention.
2 is a conceptual diagram for explaining an operation of a second processor.
3 is a flowchart of a method for detecting an object using an acoustic signal according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components may be selected among the embodiments. It can be combined and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention pertains, unless specifically defined and described explicitly. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art.

In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as "at least one (or one or more) of A and (and) B, C", it is combined with A, B, C It may include one or more of all possible combinations.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are only used to distinguish the component from other components, and are not limited to the essence, order, or order of the component by the term.

And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include a case of 'connected', 'coupled' or 'connected' due to another element between the other elements.

In addition, when it is described as being formed or disposed on "above (above) or under (below)" of each component, the top (above) or bottom (below) is one as well as when two components are in direct contact with each other. Also includes a case in which another component as described above is formed or disposed between two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upper direction but also a lower direction based on one component may be included.

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components are given the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 is a block diagram of an object detecting apparatus using an acoustic signal according to an embodiment of the present invention. Referring to FIG. 1 , an object detecting apparatus 100 according to an embodiment of the present invention includes an acoustic sensor 110 , an acoustic signal conversion unit 120 , an operation unit 130 , a determination unit 140 , and a notification unit 150 . It may be composed of

The object sensing apparatus 100 according to the present invention may be implemented as a separate device or may be implemented by being built-in in a smart phone, vehicle, bicycle, earphone, or the like. In the embodiment of the present invention, the object sensing apparatus 100 will be described as an example that is implemented as a separate device. The object detection device implemented as a separate device may be mounted on a portable device, vehicle, bicycle, inside a building, etc. to detect an approaching object and output a notification signal to the outside.

The acoustic sensor 110 may detect an externally generated acoustic signal. For example, the acoustic sensor 110 may include a microphone. In an embodiment of the present invention, the acoustic sensor 110 is an omni-directional microphone that captures sounds from all directions with uniform sensitivity, and may respond to sounds that have no directivity or come from all directions. The acoustic sensor 110 may detect an acoustic signal in an audible frequency range within an audible 40Hz to 20kHz range.

The sound signal converter 120 may convert the sensed sound signal into a spectrum signal in a frequency domain. The sound signal converter 120 may sample an analog sound signal and convert it into a digital signal. The acoustic signal converter 120 may calculate a frequency value by using a Fast Fourier Transform (FFT) with respect to the converted digital signal, and may calculate a spectrum signal from the calculated frequency value.

The calculator 130 may calculate a magnitude value and a phase value of the spectrum signal, and may calculate a sum of the magnitude value change amount and the phase value change amount according to time change.

The operation unit 130 may include a first processor 131 and a second processor 132 .

The first processor 131 may calculate a first section in which the magnitude value between successive frames increases by using the spectrum signal, and calculate a first parameter obtained by summing changes in the magnitude value in the first section.

The first processor 131 may calculate the first parameter according to Equations 1 and 2 below.

는 주파수 인덱스,

은 시간 인덱스, X_k(n)은 K주파수 대역 스펙트럼 신호의 n번째 프레임을 의미한다. 제1프로세서는 모든 주파수에 대해

과

번째의

의 크기 차의 합인

을 산출한다. 제1프로세서(131)는

번째 프레임의 에너지가

번째 프레임의 에너지보다 작은 경우 그 의미를 갖지 않으므로 반파 정류 함수인

를 이용해 음수의 값을 0으로 변환한다. 이를 통하여 제1프로세서(131)는 연속된 프레임 사이의 크기값이 증가하는 제1구간에서 크기값의 변화량을 합산한 제1파라미터를 산출할 수 있다.In Equations 1 to 2, SD(n) is the first parameter, N is a natural number,

is the frequency index,

is the time index, X _k (n) means the nth frame of the K frequency band spectrum signal. The first processor for all frequencies

and

second

is the sum of the size differences of

to calculate The first processor 131 is

energy of the second frame

If it is less than the energy of the second frame, it has no meaning, so it is

to convert negative values to 0. Through this, the first processor 131 may calculate a first parameter obtained by summing changes in the size value in the first section in which the size value between consecutive frames increases.

That is, the first processor 131 analyzes the increase and decrease of energy for each frequency, and extracts only a section in which the energy of an arbitrary frame is increased than the energy of the previous frame. Since the energy of specific frequencies increases when an object is detected, the first processor 131 may detect a signal that generates a large amount of energy instantaneously with high accuracy. In general, in an acoustic signal, energy increases when a detection distance approaches or moves at a high speed, so the first processor 131 may calculate a first parameter for detecting such an object.

The first parameter indicates very good object detection efficiency when the level of ambient noise is small. However, efficiency may be reduced when temporarily subjected to large energy interference.

The second processor 132 calculates a second section in which the magnitude and phase values between consecutive frames are increased by using the spectral signal, and a second section obtained by summing the Euclidean distance values of the magnitude and phase values between frames in the second section. Two parameters can be calculated.

The second processor 132 may detect an object by introducing the Euclidean distance measurement method to the magnitude and phase of the acoustic signal between the nth frame and the n−1th frame analyzed in the frequency domain.

The second processor 132 may calculate the second parameter according to Equations 3 to 6 below.

은

번째와

번째 사이의 위상 변화량이다. 제2프로세서(132)는 연속된 프레임 사이의 유클리드 거리를 측정함으로써 에너지 변화률이 크고 큰 위상 변화를 갖는 시점을 검출할 수 있다. 제2파라미터를 이용하면 일시적인 에너지 간섭이 존재하는 경우에도 높은 정확도로 물체 감지가 가능하다. 즉 일관적인 물체 감지 성능을 나타낼수 있다.In Equations 3 to 6, ED(n) is the second parameter, k is the frequency index, n is the time index, X _k (n) is the nth frame of the k frequency band spectrum signal, ψ _k (n) is the k frequency band the phase of the nth frame of the spectral signal,

silver

second and

is the amount of phase change between The second processor 132 may detect a time point having a large energy change rate and a large phase change by measuring the Euclidean distance between successive frames. By using the second parameter, it is possible to detect an object with high accuracy even in the presence of temporary energy interference. That is, consistent object detection performance can be exhibited.

2 is a conceptual diagram for explaining the operation of the second processor 132 . 1 and 2 , the second processor 132 may improve object detection accuracy by using a second parameter in consideration of both energy and phase. In addition, by approaching the concept of a phasor in the complex plane, the magnitude and phase characteristics of the acoustic signal can be simultaneously considered for object detection. In particular, since tonal changes are detected regardless of the height of the frequency, it is possible to compensate for the disadvantage of the first parameter and thus have a stronger object detection effect.

When the phase angle between the two phasors is 0, a simple process is possible because only a change in the magnitude of the two phasors needs to be observed. That is, the amount of computation can be reduced. On the other hand, when the phase angle between the two phasers is not 0, the amount of phase change and the magnitude must be considered at the same time. In this case, the amount of processing is increased, but the object detection accuracy can be greatly improved compared to the case where only the magnitude change is detected.

The calculator 130 may calculate a sum value by summing the first parameter and the second parameter.

In this case, the calculating unit 130 may calculate the sum value by giving weights to the first parameter and the second parameter, respectively.

The calculator 130 may calculate the sum value according to Equation 7 below.

In Equation 7, NC(n) is the sum, SD(n) is the first parameter, ED(n) is the second parameter, a is the first weight, and b is the second weight.

The calculator 130 may set the size of the first weight value and the second weight value in consideration of at least one of an ambient noise level and energy interference.

For example, when the level of ambient noise is less than or equal to a preset level, the calculator 130 may set the value of the first weight to be greater than the value of the second weight. Through this, when the ambient noise is relatively large, the weight of the first parameter in the summation value can be set to be large.

Alternatively, when the level of the ambient noise is greater than the preset level, the calculator 130 may set the value of the second weight to be smaller than the value of the second weight. Through this, when the ambient noise is relatively small, the weight of the first parameter in the summed value can be set to be small.

The ambient noise level may be calculated by filtering noise from the acoustic signal detected by the acoustic sensor.

Alternatively, the calculator 130 may set the value of the second weight to be greater than the value of the first weight when the magnitude of the interference signal applied to the acoustic signal sensed by the acoustic signal converter is greater than the magnitude of the preset energy. Through this, when the signal interference is relatively large, the weight of the second parameter in the summation value can be set to be large.

Alternatively, the calculator 130 may set the value of the second weight to be smaller than the value of the first weight when the magnitude of the interference signal applied to the acoustic signal sensed by the acoustic signal converter is less than or equal to the preset energy. Through this, when the signal interference is relatively small, the weight of the first parameter in the summation value can be set to be large.

The magnitude of the interference signal may be calculated through analysis of the spectrum signal.

Through this, object detection efficiency can be greatly improved by setting the weight of the first parameter to be large when the level of ambient noise is small, and setting the weight of the second parameter to be large when receiving relatively large energy interference.

The determination unit 140 may determine that the object approaches when the number of times the sum value exceeds the preset reference value is greater than or equal to the preset reference number in succession. The reference value and the reference number may be set differently depending on the use environment and purpose of the object sensing device. For example, in a situation in which the speed of the object detection apparatus and the user's stability are more required, the motion sensitivity of the object detection apparatus may be set to be high by setting the reference value and the reference number to be low. Alternatively, in a situation in which the accuracy of the object detecting apparatus is required to be higher, the motion sensitivity of the object detecting apparatus may be set to be low by setting the reference value and the reference number to be high.

Also, the determination unit 140 may determine the proximity risk of the object according to the size of the summation value. When the sum value exceeds 200% of the preset reference value, the determination unit 140 determines that the proximity speed of the object is very high, and may set the highest first proximity risk. In addition, when the size of the sum value exceeds 150% of the preset reference value and is less than 200%, the determination unit 140 may set the second proximity risk, which is a lower level than the first proximity risk. In addition, the determination unit 140 may set the third proximity risk, which is a level lower than the second proximity risk, when the size of the sum exceeds 100% of the preset reference value and is less than 150%.

The determination unit 140 may set different types of notification signals output from the notification unit according to the degree of proximity risk.

The notification unit 150 may output a notification signal under the control of the determination unit 140 .

Through this, when emergency vehicles such as ambulances and fire trucks are approaching automatically in the vehicle, objects such as drones that are illegally approaching public institutions are detected, or when cars, bicycles, etc. It can be automatically detected and alerted to smartphone users as an alert.

3 is a flowchart of a method for detecting an object using an acoustic signal according to an embodiment of the present invention. Referring to FIG. 3 , first, a sound sensor detects an external sound signal ( S301 ).

Next, the sound signal converter converts the sensed sound signal into a spectrum signal in the frequency domain ( S302 ).

Next, the operation unit calculates a first section in which the magnitude value between consecutive frames increases by using the spectrum signal, and calculates a first parameter obtained by summing changes in the magnitude value in the first section ( S303 ).

In addition, the operation unit calculates a second section in which the magnitude and phase values between consecutive frames are increased by using the spectrum signal, and a second parameter obtained by summing the Euclidean distance values of the magnitude values and the phase values between frames in the second section. Calculate (S304).

The process of calculating the first parameter and the process of calculating the second parameter may be performed simultaneously or one process may be performed before the other process.

Next, the calculator calculates a sum value by summing the first parameter and the second parameter. In this case, the operation unit may calculate the sum value by giving weights to the first parameter and the second parameter, respectively ( S305 ).

Next, the determination unit determines that the object approaches when the number of times the sum value exceeds the preset reference value is greater than or equal to the preset reference number in succession (S306).

Next, when it is determined that the object is approaching, the notification unit outputs a notification signal under the control of the determination unit (S307).

The term '~ unit' used in this embodiment means software or a hardware component such as a field-programmable gate array (FPGA) or ASIC, and '~ unit' performs certain roles. However, '-part' is not limited to software or hardware. The '~ unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

100: object detection device
110: sound sensor
120: sound signal conversion unit
130: arithmetic unit
140: judgment unit
150: notification unit

Claims (10)

an acoustic sensor for detecting an externally generated acoustic signal;
an acoustic signal converter converting the sensed acoustic signal into a spectrum signal in a frequency domain;
an operation unit calculating the magnitude value and the phase value of the spectrum signal, and calculating a sum of the magnitude value change amount and the phase value change amount according to time change; and
and a determining unit that determines that the object approaches when the number of times the sum value exceeds the preset reference value is greater than or equal to the preset reference number in succession.
According to claim 1,
The calculation unit,
a first processor for calculating a first section in which a magnitude value between consecutive frames increases by using the spectrum signal, and calculating a first parameter obtained by summing changes in magnitude values in the first section; and
Calculating a second section in which the magnitude value and the phase value between consecutive frames are increased using the spectrum signal, and calculating a second parameter obtained by summing the Euclidean distance values of the magnitude value and the phase value between frames in the second section An object detection apparatus using an acoustic signal including a second processor.
3. The method of claim 2,
The calculating unit sums the first parameter and the second parameter to calculate the summed value of the object detecting device using an acoustic signal.
4. The method of claim 3,
The calculation unit is an object detecting apparatus using an acoustic signal to calculate the sum value by giving weights to the first parameter and the second parameter, respectively.
According to claim 1,
The object detection apparatus using an acoustic signal further comprising a notification unit for outputting a notification signal under the control of the determination unit.
detecting, by an acoustic sensor, an externally generated acoustic signal;
converting the sensed sound signal into a spectrum signal in a frequency domain;
calculating a magnitude value and a phase value of the spectrum signal, and calculating a sum of the magnitude value change amount and the phase value change amount according to time change; and
and determining that the object is approaching when the number of times the sum value exceeds a preset reference value is greater than or equal to the preset reference number in succession.
7. The method of claim 6,
Calculating the summed value includes:
calculating a first section in which a magnitude value between consecutive frames increases by using the spectrum signal, and calculating a first parameter obtained by summing changes in magnitude values in the first section; and
Calculating a second section in which the magnitude value and the phase value between consecutive frames are increased using the spectrum signal, and calculating a second parameter obtained by summing the Euclidean distance values of the magnitude value and the phase value between frames in the second section An object detection method using an acoustic signal comprising the steps of.
8. The method of claim 7,
Calculating the summed value includes:
and calculating the sum value by summing the first parameter and the second parameter.
9. The method of claim 8,
Calculating the summed value includes:
and calculating the sum value by giving weights to the first parameter and the second parameter, respectively.
7. The method of claim 6,
The method of detecting an object using an acoustic signal further comprising the step of outputting a notification signal when it is determined that the object approaches.

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