Apparatus for estimating sound source direction from correlation between spatial transfer functions of sound signals on separate channels

A mobile phone terminal set comprising an apparatus for estimating a direction of a sound source, said apparatus comprising:

• a plurality of sound receivers each for capturing sound to produce on a channel an electric signal corresponding to the sound;
• a storage for storing data on reverse characteristics of spatial transfer functions, each of which is defined on sound transmitted from different ones of virtual sound source positions to different ones of said plurality of sound receivers, the virtual sound source positions being assigned with respect to each of said plurality of sound receivers;
• a sound signal estimator for applying the electric signal on each of the channels to the reverse characteristics of the spatial transfer functions stored in connection with the respective sound receiver with respect to the virtual sound source positions to thereby estimate a sound source signal at a sound source position associated with the sound captured;
• a function generator operative in response to the sound source signals estimated in connection with the electric signals on the respective channels for generating a decision function representing coincidence between the sound source signals estimated for the sound source positions associated with the sounds captured on the respective channels;
• and
• a direction determiner for using the decision function generated to determine a direction of the sound source position associated with the sound captured on the respective channels, thereby producing information on the direction.

A non-transitory computer-readable medium on which is stored a program for controlling, when installed in and executed by a computer, the computer to estimate a direction of a sound source from electric signals which a plurality of sound receivers capture sound to produce on respective channels, said program allowing the computer to act as:

• a storage for storing data on reverse characteristics of spatial transfer functions, each of which is defined on sound transmitted from different ones of virtual sound source positions to different ones of said plurality of sound receivers, the virtual sound source positions being assigned with respect to each of said plurality of sound receivers;
• a sound signal estimator for applying the electric signal on each of the channels to the reverse characteristics of the spatial transfer functions stored in connection with the respective sound receiver with respect to the virtual sound source positions to thereby estimate a sound source signal at a sound source position associated with the sound captured;
• a function generator operative in response to the sound source signals estimated in connection with the electric signals on the respective channels for generating a decision function representing coincidence between the sound source signals estimated for the sound source positions associated with the sounds captured on the respective channels;
• and
• a direction determiner for using the decision function generated to determine a direction of the sound source position associated with the sound captured on the respective channels, thereby producing information on the direction.

A method for estimating a direction of a sound source, comprising:

• using a plurality of sound receivers each capturing sound to produce on a channel an electric signal corresponding to the sound;
• storing in a storage data on reverse characteristics of spatial transfer functions, each of which is defined on sound transmitted from different ones of virtual sound source positions to different ones of said plurality of sound receivers, the virtual sound source positions being assigned with respect to each of the plurality of sound receivers;
• applying the electric signal on each of the channels to the reverse characteristics of the spatial transfer functions stored in connection with the respective sound receiver with respect to the virtual sound source positions to thereby estimate a sound source signal at a sound source position associated with the sound captured;
• using the sound source signals estimated in connection with the electric signals on the respective channels to generate a decision function representing coincidence between the sound source signals estimated for the sound source positions associated with the sounds captured on the respective channels;
• and
• using the decision function generated to determine a direction of the sound source position associated with the sound captured on the respective channels, thereby producing information on the direction.