JP5680340B2 - Sound source direction estimation device - Google Patents

Description

  The present invention relates to a sound source direction estimating device that estimates the direction of a sound source (for example, a vehicle that emits running sound).

  As a conventional sound source direction estimating device, for example, as described in Patent Document 1, a signal arrival time difference when a sound wave emitted by an approaching vehicle reaches two microphones (sound collecting units) mounted on the own vehicle is calculated. There is known one that calculates and determines the arrival direction of an approaching vehicle from the arrival time difference.

Japanese Utility Model Publication No. 5-92767

  By the way, the difference in signal arrival time when the sound wave reaches the two microphones varies depending on the position change of the microphone. However, in the above prior art, no consideration is given to the change in the position of the microphone. For this reason, when the position of the microphone changes due to the movement of the host vehicle, the direction of the sound source cannot be estimated accurately.

  An object of the present invention is to provide a sound source direction estimation device that can estimate the direction of a sound source with high accuracy regardless of a change in the position of a sound collection unit.

The sound source direction estimating apparatus of the present invention includes two phase calculations for calculating the phases of sound received by a plurality of sound collecting units that receive sound from a sound source and two adjacent sound collecting units among the plurality of sound collecting units. means, and the position change detection means for detecting a positional change of the sound collector, based on the calculation results of the two phase calculation means, according to the position change of the sound collector detected by the position deviation detection means, the two two phase difference calculating means for calculating a phase difference of the sound received by the sound collecting unit, respectively, based on the information on the position change of the phase difference calculated and collected section by two phase difference calculation means, the sound source two first sound source direction calculation means for calculating the direction and the arrival time difference calculating means for calculating an arrival time difference between two notes to sound collecting units of the sound source, based on the arrival time difference calculated by the arrival time difference calculating means , Calculate the direction of the sound source A sound source for obtaining a final sound source direction based on the sound source direction calculated by the two sound source direction calculating means, the two sound source direction calculating means, and the sound source direction calculated by the second sound source direction calculating means. And a direction correcting means .
The sound source direction estimating apparatus according to the present invention includes two sound collectors that receive sound from a sound source, and two phases for calculating phases of sound received by two adjacent sound collectors among the plurality of sound collectors. Based on the calculation result of the phase calculation means, the position change detection means for detecting the position change of the sound collection section, and the two phase calculation means, according to the position change of the sound collection section detected by the position change detection means, Two first phase difference calculating means for calculating the phase difference of the sound received by the two sound collecting sections, information on the phase difference calculated by the two first phase difference calculating means and the position change of the sound collecting section; , Two first sound source direction calculating means for calculating the direction of the sound source, second phase difference calculating means for calculating the phase difference of the sound obtained by the two phase calculating means, and second phase difference calculating Based on the phase difference calculated by the means On the basis of the direction of the sound source calculated by the two first sound source direction calculating means and the direction of the sound source calculated by the second sound source direction calculating means. The sound source direction correcting means for obtaining the direction is provided.

  In such a sound source direction estimating apparatus of the present invention, the position change of the sound collecting unit that receives the sound from the sound source is detected, and the phase difference of the sound received by the sound collecting unit according to the position change of the sound collecting unit And the direction of the sound source is calculated on the basis of the phase difference and the information related to the position change of the sound collecting unit. Thereby, even if the position of the sound collection unit changes, the influence of the change in position can be eliminated, and the direction of the sound source can be estimated with high accuracy.

Preferably, the position change detecting means has means for detecting the moving speed of the sound collecting section, and the first sound source direction calculating means is f for the sound source frequency, c for the sound speed, v for the moving speed of the sound collecting section, When the position change time of the sound collecting unit is Δt and the phase difference is Θ (Δt) −Θ (0), the angle θ _v formed by the moving direction of the sound collecting unit and the direction of the sound source with respect to the sound collecting unit is expressed as θ _v = cos ⁻¹ [(c / v) {(Θ (Δt) −Θ (0)) / 2πfΔt} −1]. In this case, the direction of the sound source can be easily and reliably calculated based on the phase difference of the sound received by the sound collection unit and information on the position change of the sound collection unit.

  According to the present invention, the direction of the sound source can be estimated with high accuracy regardless of the change in the position of the sound collection unit. Thereby, for example, even when another vehicle approaches when the host vehicle is traveling, the arrival direction of the other vehicle can be estimated with high accuracy.

It is a block diagram which shows schematic structure of one Embodiment of the sound source direction estimation apparatus concerning this invention. It is a figure which shows the functional block of ECU shown in FIG. It is a conceptual diagram which shows the position change of a microphone array. It is a conceptual diagram which shows the relationship between the arrangement direction of a microphone, the moving direction of a microphone array, and a sound source direction. FIG. 3 is a diagram showing functional blocks of a modified example of the ECU shown in FIG. 2. It is a figure which shows the functional block of the other modification of ECU shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a sound source direction estimating apparatus according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a sound source direction estimating apparatus according to the present invention. The sound source direction estimation device 1 of this embodiment is a device that is mounted on a vehicle and estimates the arrival direction of an approaching vehicle that emits running sound.

  In FIG. 1, a sound source direction estimating device 1 includes a microphone array (sound collecting unit) 3 composed of a plurality of microphones 2 (see FIG. 2 and the like) that receives a traveling sound of an approaching vehicle and converts it into an electric signal, and a vehicle speed of the host vehicle. And a ECU (Electronic Control Unit) 5 connected to the microphone array 3 and the speed sensor 4. The microphones 2 are installed so as to be lined up at regular intervals d in the width direction of the host vehicle (see FIG. 4). Note that the arrangement direction of the microphones 2 is not necessarily the width direction of the host vehicle. Further, the microphones 2 do not have to be arranged at regular intervals, and it is sufficient that the intervals between the microphones 2 are known.

  The ECU 5 includes a CPU, a memory such as a ROM and a RAM, an input / output circuit, and the like. As shown in FIG. 2, the ECU 5 includes phase calculation units 6A and 6B, delay phase calculation units 7A and 7B, phase difference calculation units 8A and 8B, sound source direction calculation units 9A and 9B, and arrival time difference calculation unit 10. And a sound source direction calculation unit 11 and a sound source direction correction unit 12.

  The phase calculation unit 6A performs fast Fourier transform (FFT) or the like on the output signal of one of the adjacent microphones 2 (referred to as a microphone 2A), and calculates the phase of the sound wave signal received by the microphone 2A.

  The delay phase calculation unit 7A calculates the phase of the sound wave signal received by the microphone 2A when the position of the microphone array 3 changes after the phase calculation unit 6A obtains the phase of the sound wave signal based on the detection value of the speed sensor 4. To do. At this time, as shown in FIG. 3, when the moving speed of the own vehicle (microphone array 3) is v and the moving time of the own vehicle (microphone array 3) is Δt, the moving distance of the microphone array 3 is v · Δt. .

  The phase difference calculator 8A calculates the amount of change (phase difference) between the phase of the sound wave signal obtained by the delay phase calculator 7A and the phase of the sound wave signal obtained by the phase calculator 6A.

The sound source direction calculation unit 9A calculates the direction of the sound source (here, an approaching vehicle that emits traveling sound) using the phase difference of the sound wave signal obtained by the phase difference calculation unit 8A and the detection value of the speed sensor 4. At this time, the sound source direction calculation unit 9A, as shown in FIG. 4, sets the angle formed by the array direction vector of the microphones 2 and the sound source direction vector to θ, and the angle formed by the movement direction vector of the microphone array 3 and the sound source direction vector. when the theta _v, calculates these angular theta, theta _v.

Specifically, when the frequency of the sound source is f and the speed of sound is c, the phase Θ (t) of the sound wave signal received by the microphone 2 is expressed by the following equation.
Θ (t) = 2πft + 2πft {vcos (θ _v ) / c} (1)

Regarding the equation (1), the phase (initial phase) of the sound wave signal received by the microphone 2 when t = 0 and the phase of the sound wave signal received by the microphone 2 when a minute time Δt has elapsed due to the movement of the microphone array 3. When the difference (phase difference) is calculated,
Θ (Δt) −Θ (0) = 2πfΔt {1 + vcos (θ _v ) / c} (2)
It becomes.

(2) is solved for expression θ _v,
cos θ _v = (c / v) {(Θ (Δt) −Θ (0)) / 2πfΔt} −1
θ _v = cos ⁻¹ [(c / v) {(Θ (Δt) −Θ (0)) / 2πfΔt} −1]
Is obtained.

By thus obtaining the phase difference of the sound wave signal at two times the angle theta _v formed between the traveling direction of the sound source direction and the vehicle (microphone array 3) can be obtained. Further, since the traveling direction of the microphone array 3 and the arrangement direction of the microphones 2 are orthogonal to each other, the angle θ formed by the sound source direction and the arrangement direction of the microphones 2 can be obtained by the following equation.
θ _v + θ = π / 2
θ = π / 2−θ _v

  Returning to FIG. 2, the phase calculation unit 6B performs FFT on the output signal of the other of the adjacent microphones 2 (referred to as a microphone 2B), and calculates the phase of the sound wave signal received by the microphone 2B.

  The delay phase calculation unit 7B calculates the phase of the sound wave signal received by the microphone 2B when the position of the microphone array 3 changes after the phase calculation unit 6A obtains the phase of the sound wave signal based on the detection value of the speed sensor 4. To do.

  The phase difference calculator 8B calculates the amount of change (phase difference) between the phase of the sound wave signal obtained by the delay phase calculator 7B and the phase of the sound wave signal obtained by the phase calculator 6B.

  The sound source direction calculation unit 9B calculates the direction of the sound source using the phase difference of the sound wave signal obtained by the phase difference calculation unit 8B and the detection value of the speed sensor 4. The calculation method at this time is the same as that of the sound source direction calculation unit 9A.

  The arrival time difference calculation unit 10 uses the spatial displacement of each microphone 2 to calculate the difference (arrival time difference) between the sound arrival time from the sound source to the microphone 2A and the sound arrival time from the sound source to the microphone 2B. calculate.

  The sound source direction calculation unit 11 calculates the direction of the sound source based on the arrival time difference for the microphones 2A and 2B calculated by the arrival time difference calculation unit 10.

  The sound source direction correcting unit 12 obtains the final sound source direction based on the sound source directions calculated by the sound source direction calculating units 9A, 9B, and 11. At this time, for example, the average value of the sound source directions calculated by the sound source direction calculation units 9A, 9B, and 11 is taken as the final sound source direction. Thereby, it is possible to correct the deviation of the calculation result of the sound source direction due to the influence of noise (noise, etc.). The sound source direction correction method is not particularly limited to the average value. Then, the sound source direction correcting unit 12 outputs the direction of the sound source finally obtained by screen display, voice, or the like and presents it to the driver.

  In the above, the speed sensor 4 constitutes a position change detecting unit that detects a position change of the sound collecting unit 3. The phase calculation units 6A and 6B, the delay phase calculation units 7A and 7B, and the phase difference calculation units 8A and 8B of the ECU 5 are the sound collection unit 3 according to the position change of the sound collection unit 3 detected by the position change detection unit. A phase difference calculating means for calculating the phase difference of the received sound is configured. The sound source direction calculation units 9A and 9B constitute sound source direction calculation means for calculating the direction of the sound source based on the phase difference calculated by the phase difference calculation means and information on the position change of the sound collection unit 3.

  As described above, in the present embodiment, the phase difference of each sound received by the same microphone 2 at two times is calculated by moving the microphone array 3, and the direction of the sound source is calculated based on the phase difference. Since it did in this way, even if the position of the microphone array 3 changes with driving | running | working of the own vehicle, the influence by the position change can be excluded and the direction of a sound source can be estimated accurately.

  At this time, the sound source direction obtained based on the phase difference of each sound received by the microphone 2A, the sound source direction obtained based on the phase difference of each sound received by the microphone 2B, and the sound source from the microphone 2A, Since the final sound source direction is obtained based on the sound source direction obtained based on the difference in sound arrival time to 2B, the estimation accuracy of the sound source direction can be further improved.

  FIG. 5 is a functional block diagram showing a modification of ECU 5 shown in FIG. In the figure, the ECU 5 has a phase difference calculation unit 20 instead of the arrival time difference calculation unit 10 described above. The phase difference calculator 20 calculates the amount of change (phase difference) between the phase of the sound wave signal obtained by the phase calculator 6A and the phase of the sound wave signal obtained by the phase calculator 6B. Then, the sound source direction calculation unit 11 calculates the direction of the sound source based on the phase difference calculated by the phase difference calculation unit 20. Other configurations are the same as those shown in FIG.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the microphone array 3 including the plurality of microphones 2 is used. However, as shown in FIG. 6, only one microphone 2 may be used. In this case, the phase calculation unit 6A, 6B, the delay phase calculation units 7A, 7B, the phase difference calculation units 8A, 8B and the phase calculation unit 6 corresponding to the sound source direction calculation units 9A, 9B, the delay phase calculation unit 7 By providing the phase difference calculation unit 8 and the sound source direction calculation unit 9 in the ECU 5, the direction of the sound source can be estimated with high accuracy even if the position of the microphone 2 changes due to the traveling of the host vehicle.

  In the above embodiment, the position change of the microphone 2 is detected by the speed sensor 4. However, the sensor used for detecting the position change of the microphone 2 is not limited to the speed sensor 4. It may be a sensor or the like.

  Furthermore, although the sound source direction estimation apparatus 1 of the above embodiment is mounted on a vehicle such as an automobile, the present invention is also applicable to a moving body other than the vehicle. In this case, the ECU may be installed outside the moving body depending on the type of the moving body.

DESCRIPTION OF SYMBOLS 1 ... Sound source direction estimation apparatus, 2 ... Microphone (sound collection part), 3 ... Microphone array (sound collection part), 4 ... Speed sensor (position change detection means), 5 ... ECU, 6A, 6B, 6 ... Phase calculation part (Phase difference calculation means), 7A, 7B, 7 ... Delay phase calculation section (phase difference calculation means), 8A, 8B, 8 ... Phase difference calculation section (phase difference calculation means), 9A, 9B, 9 ... Sound source direction calculation Part (sound source direction calculation means).

Claims (3)

A plurality of sound collection units that receive sound from the sound source;
Two phase calculation means for calculating the phase of the sound received by two adjacent sound collecting parts among the plurality of sound collecting parts;
Position change detecting means for detecting a position change of the sound collecting unit;
Based on the calculation result of the two phase calculation means for calculating in accordance with the position change of the detected the sound collecting unit by the position change detection means, the phase difference of the sound received by the two sound collecting portion respectively Two phase difference calculating means;
Two first sound source direction calculating means for respectively calculating the directions of the sound sources based on the phase difference calculated by the two phase difference calculating means and the information on the position change of the sound collecting unit ;
Arrival time difference calculating means for calculating a difference in arrival time of sound from the sound source to the two sound collecting units;
Second sound source direction calculating means for calculating the direction of the sound source based on the arrival time difference calculated by the arrival time difference calculating means;
Sound source direction correction for obtaining a final sound source direction based on the direction of the sound source calculated by the two first sound source direction calculating means and the direction of the sound source calculated by the second sound source direction calculating means. sound source direction estimating apparatus comprising: a means. A plurality of sound collection units that receive sound from the sound source;
Two phase calculation means for calculating the phase of the sound received by two adjacent sound collecting parts among the plurality of sound collecting parts;
Position change detecting means for detecting a position change of the sound collecting unit;
Based on the calculation result of the two phase calculation means, the phase difference between the sounds received by the two sound collecting sections according to the position change of the sound collecting section detected by the position change detecting means is calculated. Two first phase difference calculating means;
Two first sound source direction calculating means for calculating the direction of the sound source based on the phase difference calculated by the two first phase difference calculating means and the information on the position change of the sound collecting unit;
Second phase difference calculating means for calculating a phase difference between the sounds obtained by the two phase calculating means;
Second sound source direction calculating means for calculating the direction of the sound source based on the phase difference calculated by the second phase difference calculating means;
Sound source direction correction for obtaining a final sound source direction based on the direction of the sound source calculated by the two first sound source direction calculating means and the direction of the sound source calculated by the second sound source direction calculating means. sound source direction estimating apparatus comprising: a means. The position change detecting means includes means for detecting a moving speed of the sound collecting unit,
The first sound source direction calculating means is configured such that the frequency of the sound source is f, the sound speed is c, the moving speed of the sound collecting unit is v, the position change time of the sound collecting unit is Δt, and the phase difference is θ (Δt) −. When θ (0) is set, an angle θ _v formed by the moving direction of the sound collecting unit and the direction of the sound source with respect to the sound collecting unit is
θ _v = cos ⁻¹ [(c / v) {(Θ (Δt) −Θ (0)) / 2πfΔt} −1]
Sound source localization device according to claim 1 or 2, characterized in that calculated by.

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