Henry G Kellett

US Patent:

43439691, Aug 10, 1982

Filed:

Aug 1, 1980

Appl. No.:

6/174662

Inventors:

Henry G. Kellett - Atkinson NH

Assignee:

Trans-Data Associates - Fallington PA

International Classification:

G10L 100

US Classification:

179 1SD

Abstract:

An apparatus and method are provided for the recognition of speech produced by various vocal pitches capable of recognition and classification of speech articulation at a real time rate. The apparatus and method assume that articulation of a given sound in an individual's speech can be approximated as the output of a specific linear filter, corresponding to the condition of the individual's vocal tract at the time of articulation, in response to an input of one or more source impulses. The invention selects one of a library of sounds, in response to a speech waveform input, by means of a bank of vocal tract inverse filters, each of which is connected to the speech waveform input. Each vocal tract inverse filter has a complex Fourier transfer function that is the reciprocal of a particular vocal tract transfer function corresponding to a specific speech sound. Thus there is one vocal tract inverse filter for each speech sound as spoken by the particular individual. The assumed vocal tract filters are thus effectively in cascade with the vocal tract inverse filters of the invention so as to form an all-pass filter which can derive the original source waveform.