JPH1164090A - Sound source detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound source detector which can discriminate the distance to a sound source, as well as the direction to the sound source and whether or not a detected sound source is a true sound source (direct sounds) or a mirror-image sound source produced by a reflecting body (reflected sounds). SOLUTION: A sound source detector detects the direction and distance to a sound source by arithmetically processing time-sequential sound signals received by means of a plurality of receiving elements 1, arranged in an array-like state by means of a CPU 6. The detecting device adds the received signals of the receiving elements 1 to each other by changing the direction angle by taking the time lags among the sound reception of the receiving elements 1 into consideration and detects the direction angle for which the added value becomes the maximum as the direction to the sound source. In addition, the detecting device adds the received signals of the receiving elements 1 to each other by using the distance to the sound source from a certain receiving element 1 as a parameter by taking the time lags among the sound reception of the receiving elements 1 into consideration and detects the distance at which the added value becomes the maximum as the distance to the sound source. Moreover, the detecting device detects whether detected sounds are direct sounds or reflected sounds in accordance with the compared results between the detected distance to the sound source and the distance to a reflecting body stored in a RAM 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound source detecting device for detecting the position of a sound source by using a plurality of sound receiving elements arranged in an array.

[0002]

2. Description of the Related Art A method is known in which a plurality of receiving elements arranged in an array receive sound from a sound source and the direction of the sound source is detected based on the result of the reception. The sound signals received in time series by a plurality of receiving elements arranged in an array are stored in memory, and the delay in the arrival of sound waves from the sound source is considered by the difference in distance according to the position of each receiving element. Then, after applying a time delay corresponding to the difference to each receiving element,
The above-described detection method utilizes a technique in which only the sound signal in a specific direction can be strengthened by adding the reception signals of the plurality of reception elements. Hereinafter, the concept of this detection method will be described.

FIG. 9 is an explanatory diagram of this conventional detection method. A plurality of receiving elements 1 are arranged in an array at an equal pitch (element spacing d). It is assumed that sound propagates from a direction shifted by θ from a direction perpendicular to the arrangement direction of the plurality of receiving elements 1.

For example, when attention is paid to two adjacent receiving elements 1A and 1B disposed at points A and B,
The sound waves propagating from the angle θ direction have the same phase in the line segment BC. Accordingly, from the time when the receiving element 1B at the point B receives the sound, the distance difference AC (= d sin θ) is delayed by the time for transmitting the sound (d sin θ / c, where c: sound speed), and the receiving element 1A at the point A Receive the sound. Receiver element 1
A and 1B hold the time-series signals received in the memories, respectively, and at the timing when the receiving element 1A at the point A receives the signals, the time-series signals from the receiving element 1B are delayed by the delay time (ds)
The signal in the past is extracted by in θ / c). Then, by adding the current received signal of the receiving element 1A and the signal that has been traced back by the delay time of the receiving element 1B,
Sound from the angle θ direction can be strengthened.

The concept between the two receiving elements as described above is
If the method is applied to all the receiving elements arranged in an array, sound coming from a specific direction can be enhanced by a plurality of receiving elements.

The addition of the reception signals of the plurality of reception elements 1 is performed while changing the direction angle θ while considering the delay time of each reception element 1. By measuring the sound intensity according to various direction angles in this way, it is possible to determine that the direction angle at which the intensity is maximum is the direction of the sound source.

[0007]

In the above-mentioned conventional example, it is possible to specify the direction of the sound source, but there is a problem that the distance to the sound source cannot be detected.

By the way, in an apparatus for detecting the position of a sound source from received signals of a plurality of receiving elements, the presence of a reflector that reflects sound cannot be ignored. FIG. 10 is a diagram for explaining the influence of the reflector on the position detection of the sound source. As shown in FIG. 10, when the reflector 11 is present near the sound source, each of the receiving elements 1 arranged in an array
Receives both the sound coming directly from the sound source 10 and the sound coming from the sound source 10 once reflected by the reflector 11. As a result, the true direction angle of the sound source 10 is detected based on the direct sound from the sound source 10 and the reflector 11
The direction angle of the mirror image 12 of the sound source 10 imaginarily generated by the reflector 11 is also detected on the basis of the reflected sound from, so that it is determined whether the reflection is the same sound source or another sound source. There is a problem that can not be performed.

Therefore, it is important to distinguish between the direction of a sound source directly received from a sound source and the direction of a sound source received from a mirrored sound source via a reflector. In the conventional example, since the distance to the sound source cannot be detected, there is a problem that such distinction of the sound source direction cannot be performed. Therefore, in the conventional example, in the case of the reflected sound, there is a possibility that the direction of the sound source is erroneously detected as if there is a true sound source at the mirror image position.

The present invention has been made in view of such circumstances, and has as its object to provide a sound source detection device capable of detecting not only the direction of a sound source but also the distance to the sound source.

Another object of the present invention is to provide a method for receiving a sound source through a reflector from a sound source that is directly received from the sound source or a mirror image-related sound source based on a distance to the detected sound source. It is an object of the present invention to provide a sound source detection device capable of determining whether a sound source direction is a true sound source or an imaginary sound source based on a mirror image.

[0012]

A sound source detecting device according to a first aspect of the present invention is a device for receiving a sound from a sound source and detecting a position of the sound source, the device being arranged in an array for receiving a sound from the sound source. A plurality of receiving elements, a means for detecting a direction of a sound source with respect to an arrangement direction of the plurality of receiving elements based on a time-series reception result of the plurality of receiving elements, and a time series of the plurality of receiving elements. Means for detecting a distance from any one of the plurality of receiving elements to a sound source based on a reception result.

In the first invention, as in the prior art, first, adding the reception signals of the plurality of reception elements while considering the delay time of each reception element arranged in an array, the direction angle is changed. The direction angle at which the result of addition is maximum is detected as the direction of the sound source. Next, the distances from a certain receiving element to the virtual sound source in the detected direction are used as parameters, and the received signals of the plurality of receiving elements are added while considering the delay time of each receiving element according to the distance. Then, the distance when the addition result becomes maximum is detected as the distance to the sound source.

A sound source detecting device according to a second aspect of the present invention is a device for receiving a sound from a sound source and detecting a position of the sound source.
A plurality of receiving elements arranged in an array for receiving a sound from a sound source, and a direction of the sound source with respect to an arrangement direction of the plurality of receiving elements is determined based on a time-series reception result of the plurality of receiving elements. Means, an arbitrary one of the plurality of receiving elements based on a time-series reception result of the plurality of receiving elements.
Means for calculating the distance from the number of receiving elements to the sound source, and means for storing the position information of the reflector that reflects the sound, the obtained direction and the obtained distance and the stored positional information of the reflector In which the position of the sound source is detected in accordance with

In the second invention, the distance to the sound source detected as in the first invention is compared with the stored positional information of the reflector, and the sound source is either a true sound source or an imaginary sound source based on a mirror image. It is determined whether the sound is a direct sound or a reflected sound. Specifically, the distance to the detected sound source and the distance to the reflector are compared, and based on the comparison result, if the former is shorter than the latter, the direct sound is used, and if the former is longer than the latter, the reflected sound is used. Determine.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a diagram showing a hardware configuration of a sound source detection device according to the present invention.
The sound source detection device holds a plurality of receiving elements 1 arranged in an array for receiving sound and a time-series analog reception signal of the receiving elements 1 provided for each of the receiving elements 1. A plurality of memories 2, an A / D converter 3 for converting an analog reception signal read from each memory 2 into a digital signal, a digital signal processing device 4 for processing an input digital signal, and displaying detection results and the like. A monitor 5 is provided. The digital signal processing device 4 has a CPU 6 for detecting a direction angle and a distance of a sound source, and a RAM 7 for storing position information of a reflector.

Each receiving element 1 receives a sound and sends the received signal to a corresponding memory 2 in time series, and each memory 2 holds it. Then, a reception signal at a specific timing as needed is read from the memory 2 and input to the A / D converter 3. The A / D converter 3 converts an analog reception signal from each memory 2 into a digital signal and outputs the digital signal to the digital signal processing device 4. The CPU 6 detects the direction angle of the sound source and the distance to the sound source based on the input digital reception signal. Also, C
The PU 6 determines whether the sound is a direct sound or a reflected sound based on the detected distance to the sound source and the position information of the reflector stored in the RAM 7. The monitor 5 has a CPU 6
The detection result and the discrimination result obtained in are displayed. Note that R
The storage contents of the AM 7 are rewritable, and when the environment of the sound field changes and the position of the reflector changes, the storage contents indicating the position information of the reflector can be rewritten.

Next, the operation will be described. FIG. 2 is a flowchart showing the processing procedure.

First, the direction angle of the sound source is detected (step S1). FIG. 3 is a diagram for explaining this detection principle. N (n = 9 in the example shown in FIG. 3) receiving elements 1 are arranged in an array at an equal pitch of a distance d. Direct sound,
Regardless of the reflected sound, a time-series received signal of the sound obtained by each receiving element 1 is stored in each memory 2. When the direction angle of the light source is a certain angle θ, for example, the reception signals at the respective receiving elements 1 are added in consideration of the delay time with respect to the receiving element 1 located at the center. That is, the digital received signal at the delay time corresponding to the position of each receiving element 1 is A
The data is sent from the / D converter 3 to the CPU 6 and subjected to addition processing. The addition signal P (θ) at that time is expressed by the following equation (1).

[0020]

(Equation 1)

T: reception time serving as a reference at the central receiving element t _k : delay time at the k-th (1 ≦ k ≦ n) receiving element x _k (t−t _k ): k-th (1 ≦ k ≦ n) received signal c at time t-t _k at the receiving device): sound speed theta: direction angles of the sound source d: pitch N _k receiving elements: k-th are assigned to the receiving element integral (center of the receiving element is 0 , And the receiving elements on the right side are sequentially 1, 2, ..., and the receiving elements on the left side are sequentially -1,-.
2, ...)

The addition signal P (θ) as described above is changed to -90
It is determined while changing θ within the range of ° ≦ θ ≦ 90 °.
Then, the magnitude of θ when the addition signal P (θ) indicates the maximum value is detected as the direction angle of the sound source. FIG. 4 is a graph showing an example of a change in the addition signal P (θ) when θ is changed. FIG. 4 shows a value of θ at which P (θ) indicates the maximum (θ in FIG.
= Θ _max ) as the direction angle of the sound source.

Next, the distance to the sound source is detected (step S2). Using the direction angle of the sound source detected in S1, the direction of the sound source is fixed, and while changing the distance, the signals received by each receiving element 1 are added in consideration of the delay time, and the distance is calculated from the addition result. Is detected. Specifically, the following method is adopted.

FIG. 5 is a diagram for explaining this detection principle. When the distance from the central light receiving element 1 to the virtual sound source in the direction of the detected direction angle is f, each reception time is considered in consideration of the delay time in each light receiving element 1 based on the sound generation time from the virtual sound source. The addition of the received signal at the element 1 is performed. That is, a digital reception signal at a delay time corresponding to the position of each reception element 1 is sent from the A / D converter 3 to the CPU 6, and the addition processing is performed. The addition signal P (f) at that time is expressed by the following equation (2).

[0025]

(Equation 2)

F: distance from the central light receiving element to the virtual sound source t: reference sound generation time t _k : delay time in the k-th (1 ≦ k ≦ n) receiving element x _k (t−t _k ): Received signal at time t-tk at _k -th (1 ≦ k ≦ n) receiving element c: Sound velocity θ: Direction angle of sound source detected in step S1 d: Pitch of receiving element N _k : k-th receiving element Integer assigned to ((1)
Same as the formula)

Here, the reason why the delay time t _k is represented by the above equation will be described with reference to FIG. Distance i-th receiving element 1 in the center on the left side and (N _i <0) and the center of the receiving element 1 is -N _i d, the distance from the center of the receiving element 1 to the virtual sound source is f , The i-th receiving element 1
The distance S _i between the virtual sound source and the virtual sound source is obtained by the cosine theorem as follows. S _i ² = f ² + (− N _i d) ² −2f · (−N _i d) · cos (90 ° + θ) = f ² + (N _i d) ² −2fN _i d sin θ Therefore, S _i = ｛ f ² + (N _i d) ² -2fN _i dsin θ｝ ^1/2 Similarly, the j-th receiving element 1 (N _j
> 0) and the center receiving element 1 is N _j d, and the distance from the center receiving element 1 to the virtual sound source is f, so the distance S between the j-th receiving element 1 and the virtual sound source is f.
_j is obtained by the cosine theorem as follows. ^{_{S j 2 = f 2 + (}} N i d) 2 -2f · (N i d) · cos (90 ° -θ) = f 2 + (N i d) 2 -2fN i dsinθ Thus, S _i = {f ^{_{2 + (N i d) 2}} -2fN i dsinθ} 1/2 Then, by dividing the resulting distance at the speed of sound c, it is possible to obtain the delay time t _k represented by the above formula.

The addition signal P (f) as described above is expressed as follows.
Ask while increasing from. Then, the addition signal P (f)
Is detected as the distance to the sound source in the case where indicates the maximum value.

FIG. 7 is a graph showing an example of a change in the addition signal P (f) when the distance f is changed. FIG. 8 is a schematic diagram showing the movement (change in distance f) of the virtual sound source. When f = f1 (FIG. 8A), the position of the virtual sound source is before the actual sound source position, and the sum signal P (f) at that time has not reached the peak. When f = f2 (FIG. 8B), the position of the virtual sound source matches the position of the actual sound source, and the sum signal P (f) at that time exhibits the maximum value. When f = f3 (FIG. 8C), the position of the virtual sound source is behind the actual sound source position, and
The sum signal P (f) at that time has fallen from the peak. Therefore, the value of f at which P (f) indicates the maximum (f (f) in FIG. 3)
= F2) is the distance to the sound source.

Using the distance to the sound source detected in this way, it is determined whether the sound source is a true sound source or an imaginary sound source by a mirror image, that is, whether it is a direct sound or a reflected sound. I do. It is determined whether or not the detected distance is shorter than the distance to the reflector previously stored in the RAM 7 (step S3). If it is short (S3: YES), the sound source is present in the area up to the reflector, so it is determined that it is an actual true sound source and a direct sound (step S4). On the other hand, if the detected distance is longer than the distance to the reflector (S3: NO), the sound source is present in a region beyond the reflector, and is a fictitious sound source by a mirror image, and is a reflected sound. It is determined that there is (Step S5).

As described above, not only the direction angle of the sound source but also the distance to the sound source can be detected, and it can be determined whether the sound is a direct sound or a reflected sound. Further, since the position information of the reflector stored in the RAM 7 can be arbitrarily rewritten or updated, it is always possible to accurately determine whether the sound is a direct sound or a reflected sound in various sound field environments. Therefore, the present invention can be applied to voice devices such as voice input devices and voice recognition devices that are expected to develop in the future.

In the above-described embodiment, the direction angle of the sound source is detected first, and then the distance to the sound source is detected. However, the order is reversed, and the distance to the sound source is detected first. Then, it is also possible to detect the direction angle of the sound source. In such a case, first, while changing the distance (f) to the sound source with reference to a certain receiving element, the distance at which the addition signal becomes maximum is detected, and then the direction angle (θ ) Is detected while detecting the direction angle at which the addition signal becomes maximum.

Further, in the above-described embodiment, a case has been described as an example in which a receiving element located at the center among a plurality of receiving elements arranged in an array is used as a reference, but the receiving elements are arranged in an array. Of course, the present invention can be similarly performed with reference to any other receiving element among these receiving elements. Further, although a case where nine receiving elements are used is shown in the drawings, this is merely an example, and it goes without saying that any number of receiving elements may be used.

[0034]

As described in detail above, the sound source detecting device of the present invention can detect not only the direction of the sound source but also the distance to the sound source, so that a more accurate position of the sound source can be detected.

Whether the detected sound source is an actual sound source or an imaginary sound source by a mirror image of a reflector is determined.
Since the discrimination can be made based on the detected distance and the position information of the reflector, the sound source can be correctly recognized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of hardware of a sound source detection device of the present invention.

FIG. 2 is a flowchart showing a processing procedure of the sound source detection device of the present invention.

FIG. 3 is a diagram for explaining a principle of detecting a direction angle of a sound source.

FIG. 4 is a graph showing a relationship between a direction angle θ and an addition signal P (θ).

FIG. 5 is a diagram for explaining a principle of detecting a distance to a sound source.

FIG. 6 is a diagram for explaining calculation of a delay time.

FIG. 7 is a graph showing a relationship between a distance f and an addition signal P (f).

FIG. 8 is a schematic diagram illustrating a relationship between a change in a distance f and a sound source.

FIG. 9 is a diagram for explaining a conventional method for detecting a direction angle of a sound source.

FIG. 10 is a diagram for explaining a problem of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiving element 2 Memory 3 A / D converter 4 Digital signal processor 5 Monitor 6 CPU 7 RAM

Claims (2)

[Claims] An apparatus for receiving a sound from a sound source and detecting the position of the sound source, comprising: a plurality of receiving elements arranged in an array for receiving a sound from the sound source; Means for detecting the direction of the sound source with respect to the arrangement direction of the plurality of receiving elements based on the reception result of the series, and based on the reception results of the time series of the plurality of receiving elements, Means for detecting the distance from any one of the receiving elements to the sound source. 2. An apparatus for receiving a sound from a sound source and detecting a position of the sound source, comprising: a plurality of receiving elements arranged in an array for receiving a sound from the sound source; Means for determining the direction of the sound source with respect to the arrangement direction of the plurality of receiving elements based on the reception result of the series, and any of the plurality of receiving elements based on the reception results of the time series of the plurality of receiving elements. Means for calculating the distance from one receiving element to the sound source, and means for storing the position information of the reflector that reflects the sound. The obtained direction, the obtained distance and the position of the stored reflector are provided. A sound source detection device configured to detect a position of a sound source according to information.