Scientific-atlanta, Inc.

Utah State University

Chien M Huang

Paul D Israelsen

Gardiner S Stiles

Qi Bi

Vector quantization of a data vector proceeds through successive stages of a multi-stage vector quantization encoder until either (i) a measure of distortion between the vector input to a given stage and the codevector selected at that stage satisfies a threshold value or (ii) the last stage of the encoder is reached. The threshold value varies according to the fullness of a buffer which stores vector quantized data to be transmitted. Consequently, the last stage reached may differ from data vector to data vector. Compression efficiency therefore improves. Preferably, the mean value of each data vector is removed prior to vector quantization.

Adaptive multi-stage vector quantization

A method for compressing data employing vector quantization is achieved by calculating the norm of an input vector and identifying a reference codebook vector which has a norm which is closest to the norm of the input vector. The distance between the input vector and the reference codebook vector selected is computed and employed to identify a vector space about the reference vector containing a subset of codebook vectors one or more of which may be closer to the input vector than the initially selected reference vector. The closest codebook vector is selected iteratively without the necessity of searching every vector in the codebook.

Growing community of inventors

Logan, UT, United States of America

Chien M Huang