Using pitch as prior knowledge in template-based speech recognition

In a previous paper on speech recognition, we showed that templates can better capture the dynamics of speech signal compared to parametric models such as hidden Markov models. The key point in template matching approaches is finding the most similar templates to the test utterance. Traditionally, this selection is given by a distortion measure on the acoustic features. In this work, we propose to improve this template selection with the use of meta-linguistic information as prior knowledge. In this way, similarity is not only based on acoustic features but also on other sources of information that are present in the speech signal. Results on a continuous digit recognition task confirm the statement that similarity between words does not only depend on acoustic features since we obtained 24% relative improvement over the baseline. Interestingly, results are better even when compared to a system with no prior information but a larger number of templates.