A one-pass strategy for keyword spotting and verification

One common method for keyword spotting in unconstrained speech is based upon a two pass strategy consisting of Viterbi-decoding to detect and segment possible keyword hits, followed by the computation of a confidence measure to verify those hits. In this paper, we propose a simple one-pass strategy where computation of the confidence measure is computed simultaneously with a Viterbi-like decoding stage. However, backtracking is not required, which when coupled with the need for only a single pass through the utterance significantly reduces the memory requirements of this algorithm. This feature makes it well suited for devices where processing power and memory are limited. Experimental results on a connected digits task show that performance of the decoding is comparable to that using a Viterbi search with backtracking. Experimental results on spotting days of the week in continuous speech indicate that the confidence measure calculated is effective in reducing the number of false alarms.