Speech recognition apparatus
US4038503A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1975 |
| Grant date | Jul 26, 1977 |
| Priority date | — |
| Expiry date | Dec 29, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L15/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In the speech recognition apparatus disclosed herein, an audio signal is digitized and a succession of short-term power spectra are generated over a time interval corresponding to a spoken word. The short-term power spectra are frequency band equalized as a function of the peak amplitude occurring in each frequency band over the word interval. The changes in amplitude in each frequency band subjective time and then a limited number of frequency band equalized spectra are selected as representing equal intervals of subjective time so as to suppress variations in rate of articulation. The selected spectra are then non-linearly sealed in amplitude and transformed so as to maximize the separation between phonetically different sounds. By means of a maximum-likelihood method, the transformed selected spectra are compared with a data base representing a vocabulary to be recognized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.