Keyword Search using Modified Minimum Edit Distance Measure

A popular approach for keyword search in speech files is the phone lattice search. Recently minimum edit distance (MED) has been used as a measure of similarity between strings rather than using simple string matching while searching the phone lattice for the keyword. In this paper, we propose a variation of the MED, where the substitution penalties are automatically derived from the phone confusion matrix of the recognizer, as compared to heuristic or class based penalties used earlier. The results show that the substitution penalties derived from the phone confusion matrix lead to a considerable improvement in the accuracy of the keyword search algorithm.