John T Godfrey

US Patent:

6658385, Dec 2, 2003

Filed:

Feb 10, 2000

Appl. No.:

09/501879

Inventors:

Yifan Gong - Plano TX
John J. Godfrey - Dallas TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G10L 1506

US Classification:

704244, 704256

Abstract:

On improved transformation method uses an initial set of Hidden Markov Models (HMMs) trained on a large amount of speech recorded in a low noise environment R to provide rich information on co-articulation and speaker variation and a smaller database in a more noisy target environment T. A set H of HMMs is trained with data provided in the low noise environment R and the utterances in the noisy environment T are transcribed phonetically using set H of HMMs. The transcribed segments are grouped into a set of Classes C. For each subclass c of Classes C, the transformation is found to maximize likelihood utterances in T, given H. The HMMs are transformed and steps repeated until likelihood stabilizes.