Maximally Informative Reduction of the Dimension of Speech Parameters
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
A frame of (speech) information characterized by an M-dimensional vector x is replaced by a m-dimensional vector y -- where m is less than M -- by a transformation y = Ax. A, an mxM matrix, is selected to maximize the mutual information between the reduced vector y and a vector quantized label of y. In a speech recognition environment, an acoustic processor is to assign an integer value it = j to a vector yt if the jth prototype among K available prototypes is closest (by some defined measure) to the spectral vector yt . The present invention involves deriving vector yt of 20-30 dimensions from a vector xt of about 200 dimensions. In determining the matrix A, let I be a random variable whose values are the labels 1,2,.....,k, and let X be a random M-dimensional speech vector.