Speech signal processing apparatus for cutting out a speech signal from a noisy speech signal

Claim 1

A signal detecting apparatus for detecting a group of an inputted speech signal based on successive intervals of said inputted speech signal including a noise, comprising: cepstrum analysis means for performing a cepstrum analysis for each successive interval of said inputted speech signal including said noise and for outputting a corresponding cepstrum analysis result indicative of a relationship between a cepstrum level and quefrency of each successive interval of said inputted speech signal; storage means for previously storing information of respective relationships between a quefrency of a cepstrum peak of speech signals of predetermined plural groups and said plural groups; signal judgment means for detecting whether each interval of said inputted speech signal is a speech signal interval containing speech based on the presence or absence of a cepstrum peak within each interval as indicated by the cepstrum analysis result outputted from said cepstrum analysis means; maximum likelihood estimation means for detecting a group of said inputted speech signal by comparing a quefrency of a cepstrum peak present within each interval as indicated by said cepstrum analysis outputted from said cepstrum analysis means with said information of respective relationships stored in said storage means; and signal output means for outputting a pair of said speech signal intervals of said inputted speech signal detected by said signal judgment means and said group detected by said maximum likelihood estimation means.