Method for recognizing a spoken word in the presence of interfering speech

A method for recognizing a spoken word in the presence of a voice message generated by voice processing system, the voice processing system having a speech recognizer, comprising the steps of:

• (a) echo cancelling the voice message and any detected speech signal to produce a residual signal;
• (b) continuously storing a portion of the residual signal that has been most recently echo cancelled;
• (c) processing the residual signal to detect a first portion of the spoken word;
• (d) upon detection of the first portion of the spoken word, retaining the stored portion of the residual signal including the first portion of the spoken word that has been most recently processed at the time of such detection, ceasing the voice message, stopping echo cancelling of the voice message and any detected speech signal and initiating speech recognition of a second portion of the spoken word;
• (e) thereafter initiating speech recognition of the first portion of the spoken word retained upon detection of the first portion of the spoken word;
• and
• (f) combining results of the recognition effected in steps (d) and (e) to determine the spoken word.

A method, using a single digital signal processor, for recognizing a spoken word in the presence of interfering speech, comprising the steps of:

• (a) echo cancelling the interfering speech and any detected speech signal with the single digital signal processor to produce a residual signal;
• (b) continuously storing a portion of the residual signal that has been most recently echo cancelled;
• (c) processing the residual signal to detect a first portion of the spoken word;
• (d) upon detection of the first portion of the spoken word, retaining the portion of the residual signal including the first portion of the spoken word that has been most recently processed at the time of such detection, ceasing the interfering speech and switching the single digital signal processor from echo cancelling of the interfering speech to speech recognition of a second portion of the spoken word;
• (e) detecting completion of the spoken word;
• (f) upon detection of completion of the spoken word, initiating speech recognition of the retained first portion of the spoken word;
• and
• (g) combining results of the speech recognition effected in steps (d) and (f) to determine the spoken word.