Multi-Stage Speech Recognition System

A computer-readable storage medium having processor executable instructions to perform multi-stage recognition of a speech signal containing semantic information of two or more classes, by performing the acts of:

• detecting and digitizing the speech signal;
• providing a database having at least one vocabulary list for each class;
• recognizing a portion of the speech signal corresponding to a first class based on a vocabulary list corresponding to the first class, to obtain a first recognition result;
• restricting a vocabulary list corresponding to a second class based on the first recognition result;
• and
• recognizing a portion of the speech signal corresponding to the second class based upon the restricted vocabulary list, to obtain a second recognition result.

A system for multi-stage speech recognition, comprising:

• an audio transducer configured to detect a speech signal;
• a sampling circuit configured to digitize the detected speech signal;
• a database configured to store at least a first and a second vocabulary list;
• a spectral analysis circuit configured to identify a portion of the speech signal corresponding to a first class and a second class;
• a recognition circuit configured to recognize the first class based on the first vocabulary list to obtain a first recognition result;
• a matching circuit configured to restrict at least one vocabulary list other than the first vocabulary list, based on the first recognition result;
• and
• the recognizing circuit configured to recognize the second class based on the restricted vocabulary list, to obtain a second recognition result.