Accession Number : ADA132475

Title :   A Cost Constrained Speech Recognition Systems.

Descriptive Note : Master's thesis,


Personal Author(s) : Davidson,Walter F

PDF Url : ADA132475

Report Date : Aug 1983

Pagination or Media Count : 102

Abstract : This paper describes the design, construction, and evaluation of a microprocessor-based, cost-constrained word recognition system. The system uses seven bandpass filters, logarithmically spaced, followed by envelope detectors. The final algorithm uses eight uniformly spaced time slices, and used dynamic programming for time warping, with a weighted Tchebycheff distance. This system resulted in 98% correct recognition for the ten digits, 0 - 9, of the training group, and 96% correct recognition for the control group. The project demonstrated the necessity for an improvement gained with time warping. Rabiner's Unconstrained Endpoint Local Minima algorithm was used to perform the time warping. For the system used, it was found that a weighted Tchebycheff distance measure performed better than the Euclidean distance measure. The parameters were weighted inversely proportional to their variances. The results, however, were found to be relatively insensitive to the weighting coefficients. The additional hardware required for a typical microprocessor system, costs under $150. The ability to build the hardware for such a low cost was due to the use of Reticon's Universal Active Filter R5620, which costs under $7.00 each.

Descriptors :   *Speech recognition, *Signal processing, *Dynamic programming, Microprocessors, Bandpass filters, Demodulators, Algorithms, Coefficients, Weighting functions, Mathematical filters, Sensitivity, Classification, Numbers, Word recognition, Low costs

Subject Categories : Computer Hardware
      Voice Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE