This article reviews human factors research on the design of systems that use speech recognition for human control of the system or that use speech generation for the display of information. Speech...

System Design for Speech Recognition and Generation

Originally presented as author's thesis (Ph D-- Massachusetts Institute of Technology), 1987

An acoustic-phonetic approach to speech recognition : application to the semivowels

An experiment was conducted to assess the potential improvement in operator performance when data entry is performed by voice input over keyboard input. In a workload condition simulating manual/vi...

Voice Entry for Reducing Pilot Workload

Integrated Voice Controls and Speech Displays for Rotorcraft Mission Management

A trainable acoustic pattern recognizer manufactured by Scope Electronics is presented. The voice command system VCS encodes speech by sampling 16 bandpass filters with center frequencies in the range from 200 to 5000 Hz. Variations in speaking rate are compensated for by a compression algorithm that subdivides each utterance into eight subintervals in such a way that the amount of spectral change within each subinterval is the same. The recorded filter values within each subinterval are then reduced to a 15-bit representation, giving a 120-bit encoding for each utterance. The VCS incorporates a simple recognition algorithm that utilizes five training samples of each word in a vocabulary of up to 24 words. The recognition rate of approximately 85 percent correct for untrained speakers and 94 percent correct for trained speakers was not considered adequate for flight systems use. Therefore, the built-in recognition algorithm was disabled, and the VCS was modified to transmit 120-bit encodings to an external computer for recognition.

Clayton R. Coler

Papers

Automatic speech recognition research at NASA-Ames Research Center