4th International Conference on Spoken Language Processing

Philadelphia, PA, USA
October 3-6, 1996

Unsupervised and Incremental Speaker Adaptation under Adverse Environmental Conditions

Keizaburo Takagi, Koichi Shinoda, Hiroaki Hattori, Takao Watanabe

Information Technology Research Laboratories, NEC Corporation, Kawasaki, Japan

A new speaker adaptation method is described. In practical applications of speaker adaptation, adaptation and testing environments change significantly and are unknown before-hand. In such cases, since the speaker adaptation adapts a reference pattern to the adaptation utterances in regard to differences in both environment and speaker at the same time, performance in speaker adaptation would be degraded. To cope with this problem, our proposed method first eliminates the environmental differences between each input utterance and a reference pattern by using a rapid environment adaptation algorithm based on spectrum equalization (RE-ALISE) [2]. Then we apply an unsupervised and incremental speaker adaptation with autonomous control using tree structure pdf's (ACTS) [1] to the environmentally adapted reference pattern. By combining these two methods, the resulting system is expected to perform well under adverse environmental conditions and to show a stable improvement regardless of the amount of adaptation data. Evaluation experiments were carried out for utterances under three vehicle speed conditions. Recognition rates for a 100-Japanese-word recognition task after 100-word adaptation were improved from 92% (ACTS alone) to 95% (proposed method).

Full Paper

Bibliographic reference.  Takagi, Keizaburo / Shinoda, Koichi / Hattori, Hiroaki / Watanabe, Takao (1996): "Unsupervised and incremental speaker adaptation under adverse environmental conditions", In ICSLP-1996, 2079-2082.