A speech recognition strategy based on making acoustic evidence and phonetic knowledge explicit

We describe a prototype implementation of a representational approach to acoustic-phonetics in knowledge-based speech recognition. Our scheme is based on the 'Speech Sketch', a structure which enables acoustic evidence and phonetic knowledge to be represented in similar ways, so that like can be compared with like. The process of building the Speech Sketch begins with spectrogram image processing and goes on to exploit elementary phonetic constraints. A multiscale approach is used throughout. The process of interpreting the Speech Sketch makes use of an object-oriented phonetic knowledge base. Objects in the knowledge base can be matched against objects in the Speech Sketch in a manner directed by the incoming evidence. This technique promises to avoid a combinatorial explosion.