Sixth European Conference on Speech Communication and Technology

Budapest, Hungary
September 5-9, 1999

Optimal Feature Sub-Space Selection Based on Discriminant Analysis

Kris Demuynck, Jacques Duchateau, Dirk Van Compernolle (1)

Katholieke Universiteit Leuven - ESAT-PSI, Heverlee, Belgium
(2) Lernout & Hauspie Speech Products, Belgium

The performance of a speech recogniser, or of any other pattern classifier, strongly depends on the input features: to obtain a good performance, the feature set needs to be both highly discriminative and compact. Linear discriminant analysis (LDA) is a common data-driven method used to find linear transformations that map large feature vectors onto smaller ones while retaining most of the discriminative power. LDA however over-simplifies the problem by condensing all class information into only two scatter matrices, hence losing important information on the individual class distributions. We therefore propose a new approach, based on the mutual information or minimum classification error paradigm, which takes all information on the individual class distributions into account while searching an optimal sub-space, thus avoiding the crude approximations done by LDA. Experiments show that the proposed scheme provides more discriminative feature vectors, leading to substantially better recognition results.

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Bibliographic reference.  Demuynck, Kris / Duchateau, Jacques / Compernolle, Dirk Van (1999): "Optimal feature sub-space selection based on discriminant analysis", In EUROSPEECH'99, 1311-1314.