Audio signal processing for separating multiple source signals from at least one source signal

Abstract

An audio signal processing device is provided whereby, from two systems of audio signals in which audio signals of multiple audio sources are included, the audio signals of the multiple audio sources can be suitably separated. The audio signal processing device transforms the two systems of audio signals into frequency region signals, calculates a level ratio or a level difference between corresponding frequency division spectrums and extracts and outputs frequency band components of and nearby values regarding the level ratio or the level difference. Predetermined transfer coefficients for each of two output channels are multiplied by the frequency region signals and respective output signals are added together. The resulting summed signals are inverse transformed to generate time-sequence signals.

1 . An audio signal processing device comprising:
 first and second orthogonal transform means for transforming two systems of input audio time-sequence signals into respective frequency region signals;   frequency division spectral comparison means for comparing a level ratio or a level difference between corresponding frequency division spectrums from said first orthogonal transform means and said second orthogonal transform means;   frequency division spectral control means comprising three or more sound source separating means for controlling a level of frequency division spectrums obtained from both or one of said first and second orthogonal transform means based on the comparison results at said frequency division spectral comparison means, so as to extract and output frequency band components of and nearby values regarding said level ratio or said level difference;   three or more coefficient multiplying means for each of two output channels for multiplying predetermined transfer coefficients for each channel of the two output channels by each of the frequency region signals from said three or more sound separating means of said frequency division spectral control means;   channel frequency region signal generating means for generating said frequency region signals for each channel by adding respective output signals of the three or more coefficient multiplying means for each of said channels; and   inverse orthogonal transform means for restoring said frequency region signals for each of said channels from said channel frequency region signal generating means into time-sequence signals;   wherein values are set corresponding to three or more sound sources localized as sound sources at predetermined positions, as values for said level ratio or said level difference, and frequency region signals regarding each of said three or more sound sources are obtained from each of said sound source separating means.   
     
     
         2 . The audio signal processing device of  claim 1 , wherein the two output channels correspond to two speakers. 
     
     
         3 . The audio signal processing device of  claim 2 , wherein the two speakers are speakers of headphones. 
     
     
         4 . The audio signal processing device of  claim 1 , wherein the first and second orthogonal transform means transform the two systems of input audio time-sequence signals into respective frequency region signals using a Fast Fourier Transform. 
     
     
         5 . An audio signal processing device comprising:
 a first and second orthogonal transformers configured to transform two systems of input audio time-sequence signals into respective frequency region signals;   a frequency division spectral comparer configured to compare a level ratio or a level difference between corresponding frequency division spectrums from said first orthogonal transformer and said second orthogonal transformer;   frequency division spectral controller comprising three or more sound source separators configured to control a level of frequency division spectrums obtained from both or one of said first and second orthogonal transformers based on the comparison results at said frequency division spectral comparer, so as to extract and output frequency band components of and nearby values regarding said level ratio or said level difference;   three or more coefficient multipliers for each channel of two output channels, the each of the three or more coefficient multipliers configured to multiply predetermined transfer coefficients for each channel of the two output channels by each of the frequency region signals from said three or more sound source separators of said frequency division spectral controller;   channel frequency region signal generator configured to generate said frequency region signals for each channel, by adding respective output signals of the three or more coefficient multipliers for each of said channels; and   inverse orthogonal transformers configured to restore said frequency region signals for each of said channels from said channel frequency region signal generator into time-sequence signals;   wherein values are set corresponding to three or more sound sources localized as sound sources at predetermined positions, as values for said level ratio or said level difference, and frequency region signals regarding each of said three or more sound sources are obtained from each of said sound source separators.   
     
     
         6 . The audio signal processing device of  claim 5 , wherein the two output channels correspond to two speakers. 
     
     
         7 . The audio signal processing device of  claim 6 , wherein the two speakers are speakers of headphones. 
     
     
         8 . The audio signal processing device of  claim 5 , wherein the first and second orthogonal transformers transform the two systems of input audio time-sequence signals into respective frequency region signals using a Fast Fourier Transform.