Signal processing system, signal processing method, and computer program product

A signal processing method comprising:

• applying, to a plurality of time series input signals, N filters, N being an integer of 2 or greater, wherein each filter has different spatial characteristics from each other and wherein the N filters are estimated by an independent component analysis of the input signals to output N output signals;
• converting the N output signals into nonnegative signals each having a nonnegative value;
• decomposing the nonnegative signals into a spatial basis, a spectral basis matrix, and an activity vector, the spatial basis comprising nonnegative three-dimensional elements comprising K first elements, N second elements, and I third elements, K being an integer of 2 or greater according to a number of signal sources, I being an integer of 2 or greater and denoting a number of frequencies, the spectral basis matrix comprising a matrix of I rows and L columns that comprises L nonnegative spectral basis vectors expressed by I-dimensional column vectors, L being an integer of 2 or greater, the activity vector comprising a nonnegative L-dimensional vector;
• and
• estimating sound source signals representing signals of the signal sources based at least in part on the N output signals using the spatial basis, the spectral basis matrix, and the activity vector.

A computer program product comprising a non-transitory computer readable medium comprising programmed instructions, wherein the instructions, when executed by a computer, cause the computer to perform:

• applying, to a plurality of time series input signals, N filters, N being an integer of 2 or greater, wherein each filter has different spatial characteristics from each other, and wherein the N filters are estimated by an independent component analysis of the input signals to output N output signals;
• converting the N output signals into nonnegative signals each having a nonnegative value;
• decomposing the nonnegative signals into a spatial basis, a spectral basis matrix, and an activity vector, the spatial basis comprising nonnegative three-dimensional elements comprising K first elements, N second elements, and I third elements, K being an integer of 2 or greater according to a number of signal sources, I being an integer of 2 or greater and denoting a number of frequencies, the spectral basis matrix comprising a matrix of I rows and L columns that comprises L nonnegative spectral basis vectors expressed by I-dimensional column vectors, L being an integer of 2 or greater, the activity vector comprising a nonnegative L-dimensional vector;
• and
• estimating sound source signals representing signals of the signal sources based at least in part on the N output signals using the spatial basis, the spectral basis matrix, and the activity vector.