Sound image localization device, sound image localization method, and program

Abstract

A sound image localizing device includes a directivity control filter design unit that computes a directivity control filter from a desired directional characteristic, a filter coefficient correction unit that corrects the directivity control filter computed by the directivity control filter design unit, and a convolution operation unit that computes an output acoustic signal by performing convolution of an input acoustic signal and the directivity control filter corrected by the filter coefficient correction unit. Filters that respectively correspond to speakers constituting a speaker array are computed by the directivity control filter design unit and the filter coefficient correction unit, an acoustic beam is generated using directivity control by the speaker array, and the acoustic beam is caused to be reflected from a wall surface or a ceiling to generate a virtual sound source.

1 . A sound image localizing device comprising:
 an objective function setting unit, including one or more processors, configured to set an objective function from a desired directional characteristic;   a constraint setting unit, including one or more processors, configured to set a linear or non-linear constraint;   an optimization unit, including one or more processors, configured to compute an optimum filter coefficient from the objective function set by the objective function setting unit and the constraint set by the constraint setting unit; and   a convolution operation unit, including one or more processors, configured to compute an output acoustic signal by performing convolution of an input acoustic signal and a directivity control filter that is computed by the optimization unit, wherein filters that respectively correspond to speakers constituting a speaker array are computed by the objective function setting unit, the constraint setting unit, and the optimization unit, an acoustic beam is generated using directivity control by the speaker array, and the acoustic beam is caused to be reflected from a wall surface or a ceiling to generate a virtual sound source.   
     
     
         2 . The sound image localizing device according to  claim 1 , wherein the constraint setting unit is configured to set at least one of a constraint that makes a value of a filter gain constant at each frequency and a constraint relating to directional characteristics that is based on the desired directional characteristic. 
     
     
         3 . A sound image localizing method comprising:
 an objective function setting step of setting an objective function from a desired directional characteristic;   a constraint setting step of setting a linear or non-linear constraint;   an optimization step of computing an optimum filter coefficient from the objective function set in the objective function setting step and the constraint set in the constraint setting step; and   a convolution operation step of computing an output acoustic signal by performing convolution of an input acoustic signal and a directivity control filter that is computed in the optimization step, wherein filters that respectively correspond to speakers constituting a speaker array are computed in the objective function setting step, the constraint setting step, and the optimization step, an acoustic beam is generated using directivity control by the speaker array, and the acoustic beam is caused to be reflected from a wall surface or a ceiling to generate a virtual sound source.   
     
     
         4 . A non-transitory computer readable medium storing one or more instructions for causing a computer to serve as the sound image localizing device according to  claim 1 . 
     
     
         5 . The sound image localizing method according to  claim 3 , wherein the constraint setting step further comprises:
 setting at least one of a constraint that makes a value of a filter gain constant at each frequency and a constraint relating to directional characteristics that is based on the desired directional characteristic.   
     
     
         6 . The non-transitory computer readable medium according to  claim 4 , wherein the constraint setting unit is configured to set at least one of a constraint that makes a value of a filter gain constant at each frequency and a constraint relating to directional characteristics that is based on the desired directional characteristic.