What's Your Sign?: Efficient Sign Coding for Embedded Wavelet Image Coding

  • Authors:
  • Aaron Deever;Sheila S. Hemami

  • Affiliations:
  • -;-

  • Venue:
  • DCC '00 Proceedings of the Conference on Data Compression
  • Year:
  • 2000

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Abstract

Both a magnitude and a sign define wavelet transform coefficients. While promising algorithms exist for efficiently coding the transform coefficient magnitudes, current wavelet image coding algorithms are not efficient at coding the sign of the transform coefficients. It is generally assumed that there is no compression gain to be obtained from entropy coding of the sign. Only recently have some authors begun to investigate this component of wavelet image coding.In this paper, sign coding is examined in detail in the context of an embedded wavelet image coder. It is shown that PSNR improvements up to .7 dB are possible from an efficient modeling and entropy coding of the coefficients signs, combined with a new extrapolation technique, which is used to improve the final estimate of insignificant coefficients. These sign coding techniques are applicable to any genre (e.g. zero-tree, context-model) of embedded wavelet image coder.