A voice command system for AUTONOMY using a novel speech alignment algorithm

The Viterbi dynamic programming algorithm is currently the de-facto standard for speech recognizers to deal with duration variations of the sub-word units of speech by properly aligning the sub-word units to the sub-word unit models. The algorithm is an integral part of the hidden Markov model speech recognizers. In this work a robust and simple voice command system is developed, implemented and tested. It uses a novel speech alignment algorithm, the so-called “run-length limited dynamic programming algorithm” (RLL-DP) instead. The voice command system described hereinafter facilitates the operation of the AUTONOMY system, which is an environmental control system combined with an alternative and augmentative communication system, using isolated words as voice commands. The activation of “run-length limits” causes a statistically significant reduction of the word error rate, even when using simple “centroid sequence word models” instead of acoustic models based on “hidden control neural networks” used in previous versions.