A survey of mixed transform techniques for speech and image coding

The goal of transform based coding is to build a representation of a signal using the smallest number of weighted basis functions possible, while maintaining the ability to reconstruct the signal with adequate fidelity. Mixed transform techniques, which employ subsets of non-orthogonal basis functions chosen from two or more transform domains, have been shown to consistently yield more efficient signal representations than those based on one transform. This paper provides a survey of mixed transform techniques, also known as multitransforms or mixed basis representations, which have been developed for speech and image coding