Patent ID: 7472059

Claim:
A method of speech classification, comprising: inputting parameters to a speech classifier, the parameters comprising speech samples, a signal to noise ratio (SNR) of the speech samples, a voice activity decision, a Normalized Auto-correlation Coefficient Function (NACF) value based on a pitch estimation, and Normalized Auto-correlation Coefficient Function (NACF) at pitch information; generating, in the speech classifier, internal parameters from the input parameters; setting a Normalized Auto-correlation Coefficient Function (NACF) threshold value for voiced speech, transitional speech and unvoiced speech based on the signal to noise ratio of the speech samples, wherein the NACF threshold value for voiced speech in a noisy speech environment is lower than the NACF threshold value for voiced speech in a clean speech environment; and analyzing the input parameters and the internal parameters to produce a speech mode classification from a group comprising a transient mode, a voiced mode, and an unvoiced mode.