Patent ID: 8321208

Claim:
An apparatus for speech processing, the apparatus being implemented by a computer programmed to execute computer-readable instructions stored in a memory, the apparatus comprising: a frame extraction unit configured to extract, using the computer, a speech signal in each frame; an information extraction unit configured to extract, using the computer, spectral envelope information of L-dimension from each frame by discrete Fourier transform, the spectral envelope information being represented by L points; a basis generation unit configured to extract, using the computer, the spectral envelope information from the speech signal to generate a basis, to minimize a first evaluation function by changing the basis and a corresponding coefficient, the first evaluation being a sum of an error term and a first regularization term, the error term being a distortion between the spectral envelope information and a linear combination of the basis with the coefficient, the first regularization term being a sparseness of the coefficient, the sparseness being a smaller value when the coefficient is closer to zero, and to select the basis for which the first evaluation function is minimized; a basis storage unit configured to store N bases (L>N>1), each basis having a different frequency band having a maximum as a peak frequency in a spectral domain having L-dimension, a value corresponding to a frequency outside the frequency band along a frequency axis of the spectral domain being zero, and two frequency bands of which two peak frequencies are adjacent along the frequency axis partially overlapping; and a parameter calculation unit configured to minimize, using the computer, a distortion between the spectral envelope information and a linear combination of each basis with the coefficient for each of L points of the spectral envelope information by changing the coefficient, and to set the coefficient of each basis for which the distortion is minimized as a spectral envelope parameter of the spectral envelope information.