WavBox 4: A Software Toolbox for Wavelet Transforms and Adaptive Wavelet Packet Decompositions

Abstract

WavBox provides both a function library and a computing environment for wavelet transforms and adaptive wavelet packet decompositions. WavBox contains a collection of these transforms, decompositions, and related functions that perform multiresolution analyses of 1-D multichannel signals and 2-D images. The current version 4.1c includes overscaled pyramid transforms, discrete wavelet transforms, and adaptive wavelet and cosine packet decompositions by best level, best basis, and matching pursuit as described by Mallat, Coifman, Wickerhauser, and other authors. WavBox also implements Taswell’s new search algorithms with decision criteria, called near-best basis and non-additive information costs respectively, for selecting bases in wavelet packet transforms, as well as Donoho and Johnstone’s wavelet shrinkage denoising methods. Various choices of filter classes (orthogonal, biorthogonal, etc), filter families (Daubechies, Vetterli, etc), and convolution versions (interval, circular, extended, etc) exist for each transform and decomposition. The software has been designed for efficient automated computation, interactive exploratory data analysis, and pedagogy. Essential features of the design include: perfect reconstruction for multiresolution decomposition of data of arbitrary size not restricted to powers of 2; both command line and graphical user interfaces with a comprehensive set of plots and visual displays; an object property expert system with artificial intelligence for configuring valid property combinations; heirarchical modules and switch-driven function suites; vector-filter and matrix-operator implementations of convolutions; extensibility for the inclusion of other wavelet filters, convolution versions, and transforms; optional arguments with built-in defaults for most m-files; and extensive on-line help and self-running tutorial demos.

WavBox 4 Copyright 1993–94 Carl Taswell; all rights reserved