Patent ID: 8468016

Claim:
A method of extracting a speech feature, the method comprising the steps of: receiving, as an input, a spectrum of a speech signal segmented into frames for each frequency bin; calculating a delta spectrum for each frame, wherein said delta spectrum is a difference of said spectrum within continuous frames for said frequency bin; storing said delta spectrum in said storage area; calculating a mel delta spectrum of said frame for each filter bank, wherein said mel delta spectrum is a total of respective products of said delta spectra for said individual frequency bins and corresponding weights of a mel filter bank; storing said mel delta spectrum in said storage area; normalizing said mel delta spectrum of said frame for said filter bank by dividing said mel delta spectrum by a function of an average mel spectrum, wherein said average mel spectrum is an average of mel spectra through all frames that comprise overall speech for said filter bank; storing said normalized mel delta spectrum in said storage area; reading said normalized mel delta spectrum for said filter bank from said storage area; and performing discrete cosine transform of said normalized mel delta spectrum, wherein a result of performing said discrete cosine transform is defined as a delta feature; and wherein at least one of the steps is carried out by a computer device.