CHAPTER Sparse component analysis R. Gribonval and M. Zibulevsky 10 10.1 INTRODUCTION Sparse decomposition techniques for signals and images underwent considerable devel- opment during the flourishing of wavelet-based compression and denoising methods [75] in the early 1990s. Some ten years elapsed before these techniques began to be fully exploited for blind source separation [72,106,66,70,116,61,15,111]. Their main impact is that they provide a relatively simple framework for separating a number of sources exceeding the number of observed mixtures. Also they greatly improve quality of sepa-