Encoding the \ell_p Ball from Limited Measurements

  • Authors:
  • Emmanuel Candes

  • Affiliations:
  • Caltech

  • Venue:
  • DCC '06 Proceedings of the Data Compression Conference
  • Year:
  • 2006

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Abstract

We address the problem of encoding signals which are sparse, i.e. signals that are concentrated on a set of small support. Mathematically, such signals are modeled as elements in the \ell_pball for some p1. We describe a strategy for encoding elements of the \ell_p ball which is universal in that 1) the encoding procedure is completely generic, and does not depend on p (the sparsity of the signal), and 2) it achieves near-optimal minimax performance simultaneously for all p \le 1. What makes our coding procedure unique is that it requires only a limited number of nonadaptive measurements of the underlying sparse signal; we show that near-optimal performance can be obtained with a number of measurements that is roughly proportional to the number of bits used by the encoder. We end by briefly discussing these results in the context of image compression.