Optimal Wavelet Packets Decomposition Based on a Rate-Distortion Optimality Criterion
We address the problem of optimal decomposition of wavelet packets (WPs) for pattern recognition based on the minimum probability of error signal representation (MPE-SR) principle. The problem is formulated as a complexity regularized optimization, where the tree-indexed structure of the WP family is used to reduce it to a type of minimum cost tree pruning problem used in regression and classification trees (CART). MPE-SR solutions are obtained for a frame level phone recognition task showing promising performance results.