Continuous speech recognition apparatus

Abstract

A conventional speech recognition network finite-state automaton, which follows regular grammar rules, is improved by adding subnetworks tapped into the original network at call and return points, whereby context-free grammar rules may be used, with avoidance of infinite loop response of a recurrent expression. A continuous speech recognition apparatus includes a standard pattern memory for storing standard patterns, a distance calculating section for calculating distances between frames of an input speech pattern and the standard patterns, an accumulation value calculating section for calculating accumulation values of the distances on matching paths which cause frames of the speech pattern and the standard patterns to correspond to each other, an accumulation value memory for storing the accumulation values, a return point memory for storing an address of a return point of a subnetwork in correspondence with the same address as that of the accumulation value memory, a call processing section for writing a minimum value of the accumulation values at a plurality of call points for the subnetwork as an initial value of the accumulation value for the subnetwork in the accumulation value memory and writing an address of a return point corresponding to the call point yielding the minimum value in the return point memory as an initial value, and a return processing section for writing an accumulation value at a terminal point of the subnetwork in the accumulation value memory addressed by the return point address stored in the return point memory at the terminal point of the subnetwork.