SPEECH DETECTION USING STOCHASTIC CONFIDENCE MEASURES ON THE FREQUENCY SPECTRUM

摘要

A probabilistic approach is used to classify each frame of the speech signal as speech or non-speech. The speech detection method is based on a frequency spectrum (24) extracted from each frame, such that the value for each frequency band is considered to be a random variable and each frame is considered to be an occurrence of these random variables. Using the frequency spectrums from a non-speech part of the speech signal, a known set of random variables is constructed (26). Next, each unknown frame is evaluated as to whether or not it belongs to this set of random variables by forming a unique random variable (preferably a chi-square value) (28) from a set of random variables associated with the unknown frame. The unique variable is normalized (30) with respect the known set, and then classified (32) as either speech or non-speech using the "Test of Hypothesis". Thus, each frame that belongs to the known set of random variables is classified as non-speech, and each frame that does not belong to the known set of random variables is classified as speech.