Constrained gradient descent algorithm for residual vector quantizer design

Residual vector quantizers have been proposed to overcome the search complexity of regular single stage vector quantizers. We present a design algorithm for residual vector quantizer codebooks. An attempt is made to make full use of the sequential search nature of the encoding process. An error energy is formulated based on the distortion criterion with a constraint imposed to optimize for the sequential search. The codebook design is formulated as multidimensional minimization problem, where the error energy is minimized to obtain the required codebooks. The proposed algorithm is based on the gradient descent algorithm