JP2523959B2 - Direction information extraction device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direction information extraction device for dividing and extracting a physical sound field in space into arbitrary directions.

Conventional Technology Conventionally, this type of direction information extraction device has been published by the Acoustical Society of Japan 1
1, 719-725 (1988), 49 omnidirectional microphones, amplifier, low-pass filter, A / D
Equipped with a converter and a phase splicer, the synthetic phase center is placed at the microphone position installed at the geometric center of all microphones, and a delay of the path length difference is added to extract direction-specific information. It is configured to be able to.

FIG. 3 shows the configuration of a conventional direction information extraction device. In FIG. 3, reference numeral 1 denotes a concentric microphone, the output of which is amplified by the amplifier 2, band-limited by the anti-aliasing filter 3, and converted into digital data by the AD converter 4. After the phase matching unit 5 corrects the path length difference between each microphone position and the center of the microphone jig when a plane wave arrives from a certain direction as a delay amount, V.
The adders 6 add the respective data arranged on the circumference of W, X, Y, and Z. Next, the digital filter 7 limits the band for each addition data, and finally, the adder 8 combines them to extract information for a certain direction. As described above, even the above-described conventional direction information extraction device can extract direction information in the horizontal plane.

SUMMARY OF THE INVENTION However, the conventional direction information extraction device using the concentric circular array microphones has a problem in that it cannot capture a wavefront other than a plane wave incident on a horizontal plane.

The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent directional information extraction device capable of separating a reflected sound from an arbitrary direction in a three-dimensional space.

Means for Solving the Problems In order to achieve the above object, the present invention provides a global microphone that collects sound on a spherical surface by horizontally and vertically driving an end of an arm to which a plurality of microphones are arbitrarily attached, Random number generating means for randomly driving the global microphone horizontally and vertically, correcting means for correcting distance difference and time difference between microphones of data collected by the global microphone, and direction information extracted from the result of the correcting means. And a direction information extracting means for performing the operation.

Effect Therefore, according to the present invention, by moving a 4-channel microphone in a three-dimensional space and recording an impulse response, information in a desired direction can be extracted, which is used for evaluation of a music hall and sound field control. It has an effect that a database or the like can be used.

Embodiment FIG. 1 shows the structure of an embodiment of the present invention.
In FIG. 1, reference numeral 11 denotes a global microphone, which has a maximum length of 2 m and a plurality of arms, for example, 4 at equal intervals.
A microphone is installed, each input is amplified by an amplifier 12, band-limited by an anti-aliasing filter 13 composed of a low-pass filter, and digitally by an AD converter 14 by the same clock controlled by a personal computer 16. After conversion, the band is further limited by the digital filter 15. The data of each channel is stored in the optical disc memory 17. Then, under the control of the personal computer 16, the horizontal movement driver 18 and the vertical movement driver 19 operate the respective pulse motors to move the global microphone 11 to the next measurement point and perform the same measurement as above. Finally, the data at each measurement point is stored in the optical disk memory 17, and then the distance difference between each measurement point with respect to the extracted direction, that is, the time delay is corrected.
20 corrections are performed and addition is performed by the addition circuit 21 for each channel.
Use as channel data. Each channel data is subjected to band limitation by a digital filter for each channel and then recombined to extract direction information. As described above, according to the above-described embodiment, since the driving of the horizontal movement driver 18 and the vertical movement driver 19 are randomly generated and randomly moved so as to collect the global microphone 11 on the spherical surface, The directional characteristic is uniform in each direction, and in particular, it has an advantage that a vertical plane wave can be extracted and also has an advantage that direction information having a high SN ratio can be extracted by performing phase correction and synchronous addition.

FIG. 2 shows a moving mechanism of the global microphone 11. Reference numeral 28 denotes a horizontal rotation mechanism, to which the horizontal rotary table 22 is connected by a rotary shaft. A pole 23 is attached to the horizontal rotary table 22 by a mounting base 24. At the other end of the pole 23, the global microphone 11 is vertically rotated 25.
Is installed through. Global microphone
The reference numeral 11 is composed of a microphone boom 26 having a maximum length of 2 m and four microphones 27 installed at equal intervals.

As described with reference to FIG. 1, when the horizontal movement pulse motor is operated by the horizontal movement driver 18, the horizontal rotary table 22
Rotates in the horizontal plane, so the global microphone
11 scans in the horizontal plane. On the other hand, when the vertical movement driver 19 operates the vertical movement pulse motor, the vertical rotation mechanism 25 causes the global microphone 11 to scan in the vertical plane. Thus, the global microphone 11 can freely scan the spherical surface by scanning in both the horizontal and vertical directions. Therefore, if microphones are set on a spherical surface, the number of microphones through which sound waves pass in a unit time becomes constant, there is no bias in the amount of time shift, and the uniformity of the amount of time shift during directional synthesis and the directional characteristics 3 Since it is possible to achieve both isotropicity in dimensions, it can be used for evaluation in a sound field space such as a music hall and creation of a sound field control database.

EFFECTS OF THE INVENTION The present invention uses a global microphone that collects sound on a spherical surface by horizontally and vertically driving the ends of an arm to which a plurality of microphones are arbitrarily attached, so that sound waves pass in a unit time by collecting sound. The number of microphones is constant, there is no bias in the amount of time shift, and the uniformity of the time shift during directivity synthesis and the three-dimensional isotropicity of the directivity characteristics can both be achieved. Further, by randomly driving the global microphone horizontally and vertically, it is possible to obtain uniform directivity characteristics in all directions.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a direction information extracting device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a global microphone of the same device, and FIG. 3 is a schematic block diagram of a conventional direction information extracting device. 11 ... Global microphone, 12 ... Amplifier, 13 ...
… Anti-aliasing filter, 14… AD converter, 15…
… Digital filter, 16… Personal computer,
17: Optical disk memory, 18: Horizontal movement driver,
19 ... Vertical movement driver, 20 ... Correction circuit, 21 ... Addition circuit.

Claims (1)

(57) [Claims] 1. A global microphone that collects sound on a spherical surface by horizontally and vertically driving an end of an arm to which a plurality of microphones are arbitrarily attached, and a random number generator that randomly drives horizontally and vertically the global microphone. A direction information extraction device comprising: means, a correction means for correcting a distance difference and a time difference between microphones of data collected by the global microphone, and a direction information extraction means for extracting direction information from a result of the correction means.