JP2574503B2 - Sound field reproduction method using compressed sound field information - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sound field reproduction method using compressed sound field information for reproducing another sound field in an arbitrary space.

2. Description of the Related Art Conventionally, this main sound field reproducing method is configured to select a signal having a large energy from a measured impulse response of a sound field to reduce the information amount of the sound field. This is a method of physically trying to reproduce an impulse response. If the information compression degree is small and there is a sufficient amount of information, an impression of a sound field can be reproduced.

Problems to be Solved by the Invention However, the conventional sound field reproducing method described above has a problem that when the compression degree is high and the amount of information decreases, the ability to reproduce the impression of the sound field decreases. An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a sound field reproducing method capable of reproducing an impression of a sound field with a high degree of compression and a small amount of information.

Means for Solving the Problems In order to achieve the above object, the present invention measures an impulse response of a sound field with a dummy head microphone installed on both ears of a dummy head, and time-seriesly measures the measured signal. Compress the sound field information using the binaural cross-correlation function,
The compression result is convolution-operated to generate a signal reproduced in an arbitrary space.

Operation Therefore, according to the present invention, by compressing the information using the time-series binaural cross-correlation of the impulse response measured by the dummy head microphone, the impression of the sound field can be reproduced with a small amount of information. .

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes a sound field to be reproduced. Reference numeral 2 denotes an impulse generator, which is connected to the amplifier 3.
Reference numeral 4 denotes a speaker that emits an impulse. Reference numeral 5 denotes a dummy hand microphone, which picks up an impulse response at positions corresponding to the left ear and the right ear, respectively. Reference numeral 6 denotes a time-series interaural cross-correlation function measuring device, which calculates a time-series interaural cross-correlation function from impulse responses of the left and right microphones of the dummy head microphone 5. Reference numeral 7 denotes an arbitrary space where a sound field is reproduced. Reference numeral 8 denotes an audio signal source, which is connected to the convolution operation unit 9. Reference numeral 10 denotes an amplifier, which is connected to the speaker 11. 12 is a listener.

Operation Next, the operation of the above embodiment will be described. First, in a sound field 1 to be reproduced, an impulse generated by an impulse generator 2 is amplified by an amplifier 3 and then radiated by a speaker 4 installed at a sound source position, and radiated by a dummy head microphone 5 installed at a listening position. The impulse responses at positions corresponding to the left and right ears are measured and output to the time series interaural cross-correlation function measuring device 6. Impulse responses at positions corresponding to the left ear and the right ear are hl (t) and hr (t), respectively. The time-series binaural cross-correlation function measuring device 6 calculates the time-series binaural cross-correlation function RCC (i, τ) of the i-th time window using the following equation.

RCC (i, τ) = ∫ TW hl (i-1) · TW + t) · hr ((i
-1) TW + t + τ) dt / ｛∫ ^TW hl ² ((i-1) TW +
t) dt · { ^TW hl ² ((i−1) · TW + t) dt} ^1/2 (1) where the time window TW is 5 to 10 ms and the interaural time difference τ
Is -1 to +1 ms.

In addition, the time τ (i) at which the RCC of each section is the maximum and the azimuth Ψ (i) at which the interaural time difference is equal to τ (i) are obtained. Next, from the impulse responses at positions corresponding to the left ear and the right ear of the dummy head microphone 5, a time Δt (i) at which the sound pressure becomes maximum in each section where the RCC is calculated is obtained. Further, the energy E (i) in each section is expressed by Equation 2
Is determined using

E (i) = 6 · log ₂ (2 ^{L 1/6} +2 ^{L r / 6} ) (2) Here, Ll and Lr correspond to the left ear and the right ear of the dummy head microphone 5 in each section, respectively. The sound pressure level at the position where

The respective time delays Δt calculated in this way
Information on (i), energy E (i), and direction angle Ψ (i) are input to the convolution calculator 9.

The audio signal output from the audio signal source 8 is subjected to a convolution operation in a convolution operation unit 9 and is amplified by an amplifier 10.
Among the speakers 11 surrounding the listener 12 in an arbitrary space 7, speakers present in a subspace including the azimuth Ψ (i) are presented with a time delay Δt (i) and energy E (i).

As described above, according to the above-described embodiment, the impulse responses at the positions corresponding to the left and right ears of the dummy head microphone 5 installed at the listening position are compressed by the time-series binaural cross-correlation function measuring device 6 for information compression. This has the advantage that the impression of the sound field can be reproduced with a small amount of information.

The present invention relates to a measuring means for measuring an impulse response of a sound field with a dummy head microphone installed on both ears of a dummy head, and a time series binaural cross-correlation function for a signal measured by the measuring means. And a signal generating means for convolving the result obtained by the compressing means to generate a signal to be reproduced in an arbitrary space. There is an advantage that an impression of a sound field can be calculated with information and reproduced in an arbitrary space.

[Brief description of the drawings]

FIG. 1 is a block diagram of a configuration used in a sound field reproducing method using compressed sound field information in one embodiment of the present invention. 1 ... sound field, 2 ... impulse generator, 3 ... amplifier,
4… Speaker, 5… Dummy Hend microphone,
6: Win-sequence binaural cross-correlation function measuring device, 7: Arbitrary space, 8: Audio signal source, 9: Convolution operation unit, 10:
... amplifier, 11 ... speaker, 12 ... listener.

Claims (1)

(57) [Claims] 1. A measuring means for measuring an impulse response of a sound field with a dummy head microphone installed on both ears of a dummy head, and a time series binaural cross-correlation function for a signal measured by the measuring means. A sound field using compressed sound field information, comprising: compression means for compressing information of a sound field using the compression means; and signal generation means for convolving the result obtained by the compression means and generating a signal reproduced in an arbitrary space. Playback method.