Combining frequency warping and spectral shaping in hmm based speech recognition
CA 2227982 C · Owner: At&T Properties, Llc · Inventors: Potamianos, Alexandros; Rose, Richard Cameron
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Frequency warping approaches to speaker normalization have been proposed and evaluated on various speech recognition tasks. In all cases frequency warping was found to significantly improve recognition performance by reducing the mismatch between test utterances presented to the recognizer and the speaker independent HMM model. This invention relates to a procedure which compensates utterances by simultaneously scaling the frequency axis and reshaping the spectral energy contour. This procedure is shown to reduce the error rate in a telephone based connected digit recognition task by 30%.
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed January 26, 1998 and granted September 17, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 26, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 26, 2020.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.