US 6,130,949 A · Method and apparatus for separation of source, program recorded medium therefor, method and apparatus for detection of sound source zone, and program recorded medium therefor

Abstract

A time difference .DELTA..tau. between the arrival of acoustic signals from sound sources to microphones 1, 2 is detected from output channel signals L, R from microphones 1, 2. By Fourier transform, the signals L, R are divided into respective frequency bands L(f1)-L(fn), R(f1)-R(fn). Differences .DELTA..tau.i (i=1, 2, . . . n) in the time-of-arrival of L(f1)-L(fn) and R(f1)-R(fn) to the microphones 1, 2 as well as a signal level difference .DELTA.Li are detected. L(f1)-L(fn), R(f1)-R(fn) are divided into a low range of fi<1/(2 .DELTA..tau.), a middle range of 1/(2 .DELTA..tau.) <fi<1/.DELTA..tau., and a high range of fi>1/.DELTA..tau.. Utilizing .DELTA..tau.i for the low range, .DELTA.Li and .DELTA..tau.i for the middle range and .DELTA.Li for the high range, a determination is made from which sound source L(fi), R(fi) are oncoming to deliver outputs separately for each sound source. The outputs are subject to an inverse Fourier transform for synthesis separately for each sound source.

Claims100

Dependent claims

A method for separating at least one sound source from a plurality of sound sources using a plurality of microphones disposed separately from one another, comprising steps of:

(a) dividing an output channel signal from each microphone into a plurality of frequency bands to produce band-divided output channel signals;
(b) detecting, for each frequency band, as band-dependent inter-channel parameter value differences, differences between the output channel signals in the value of a parameter of an acoustic signal arriving at the microphones from each of the sound sources, said differences being attributable to the locations of the plurality of microphones;
(c) on the basis of the band-dependent inter-channel parameter value differences for each frequency band, determining which one of the respective band-divided output channel signals in each frequency band comes from which one of the sound sources;
(d) selecting particular band-divided output channel signals determined in step (c) to have been generated from at least one of the sound sources;
and
(e) combining the selected band-divided output channel signals selected for said at least one of the sound sources in the step (d) into a resulting sound source signal from said at least one of the sound sources.

3 more elements

A method of separating at least one sound source from a plurality of sound sources by using a plurality of microphones located in spaced relation to each other, comprising the steps of:

(a) determining power spectrums for output channel signals from the respective microphones;
(b) dividing the power spectrum of each channel into a plurality of frequency bands so that principally spectrum components from a single one of the sound sources are contained in each band;
(c) detecting, for each band, differences in the divided power spectrums between the channels as band-dependent inter-channel level differences;
(d) on the basis of the band-dependent inter-channel level differences for the respective bands, determining which one of the respective divided power spectrums in each frequency band comes from which one of the sound source signals;
(e) on the basis of a determination rendered in step (d), selecting particular band divided spectrums of at least one of the channels corresponding to at least one of the sound sources;
and
(f) combining the selected band divided spectrums selected in step (e) into a resulting sound source signal.

4 more elements

An apparatus for separating at least one sound source from a plurality of sound sources using a plurality of microphones disposed in spaced relation to one another comprising:

band dividing means for dividing an output channel signal from each of the respective microphones into a plurality of frequency bands to produce band-divided output channel signals such that each of the band-divided output channel signals essentially and principally comprises a component of an acoustic signal from only one of the sound sources;
means for detecting, for each frequency band, as band-dependent inter-channel parameter value differences, differences between the output channel signals in the value of a parameter of an acoustic signal arriving at the microphones from each of the sound sources, said differences being attributable to the locations of the plurality of microphones;
means for determining, on the basis of the band-dependent inter-channel parameter value differences for each frequency band, which one of the respective band-divided output channel signals in each frequency band comes from which one of the sound sources;
selecting means for selecting particular band-divided output channel signals determined by the determining means to have been generated from at least one of the sound sources;
and
combining means for combining the selected band-divided output channel signals selected by said selecting means into a resulting sound source signal from said at least one of the sound sources.

3 more elements

A record medium having recorded therein a program for implementing a method for separating at least one sound source from a plurality of sound sources using a plurality of microphones disposed in spaced relation to one another, the recorded program comprising the steps of:

(a) dividing an output channel signal from each microphone into a plurality of frequency bands chosen small enough to assure that each of the band-divided output channel signals essentially and principally comprises a component of an acoustic signal from only one of the sound sources;
(b) detecting, for each frequency band, as band-dependent inter-channel parameter value differences, differences between the output channel signals in the value of a parameter of an acoustic signal arriving at the microphones from each of the sound sources, said differences being attributable to the locations of the plurality of microphones;
(c) on the basis of the band-dependent inter-channel parameter value differences for each frequency band, determining which one of the respective band-divided output channel signals for in each frequency band comes from which one of the sound sources;
(d) selecting particular band-divided output channel signals determined in step (c) to have been generated from at least one of the sound sources;
and
(e) combining the selected band-divided output channel signals selected for said at least one of the sound sources in step (d) into a resulting sound source signal from said at least one of the sound sources.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for separation of source, program recorded medium therefor, method and apparatus for detection of sound source zone, and program recorded medium therefor

Life of this patent

Method and apparatus for separation of source, program recorded medium therefor, method and apparatus for detection of sound source zone, and program recorded medium therefor

Life of this patent

Abstract

Claims100