Title :
Image coding using wavelet transforms and entropy-constrained trellis-coded quantization
Author :
Sriram, Parthasarathy ; Marcellin, Michael W.
Author_Institution :
Digital Commun. Div., Rockwell Int. Corp., Newport Beach, CA, USA
fDate :
6/1/1995 12:00:00 AM
Abstract :
The discrete wavelet transform has recently emerged as a powerful technique for decomposing images into various multi-resolution approximations. Multi-resolution decomposition schemes have proven to be very effective for high-quality, low bit-rate image coding. In this work, we investigate the use of entropy-constrained trellis-coded quantization (ECTCQ) for encoding the wavelet coefficients of both monochrome and color images. ECTCQ is known as an effective scheme for quantizing memoryless sources with low to moderate complexity, The ECTCQ approach to data compression has led to some of the most effective source codes found to date for memoryless sources. Performance comparisons are made using the classical quadrature mirror filter bank of Johnston and nine-tap spline filters that were built from biorthogonal wavelet bases. We conclude that the encoded images obtained from the system employing nine-tap spline filters are marginally superior although at the expense of additional computational burden. Excellent peak-signal-to-noise ratios are obtained for encoding monochrome and color versions of the 512×512 “Lenna” image. Comparisons with other results from the literature reveal that the proposed wavelet coder is quite competitive
Keywords :
band-pass filters; entropy codes; filtering theory; image coding; image resolution; quantisation (signal); source coding; splines (mathematics); trellis codes; wavelet transforms; ECTCQ; biorthogonal wavelet bases; color images; data compression; entropy-constrained trellis-coded quantization; image decomposition; low bit-rate image coding; memoryless sources; monochrome images; multiresolution approximations; multiresolution decomposition; nine-tap spline filter; peak-signal-to-noise ratios; performance comparisons; quadrature mirror filter bank; source codes; wavelet coder; wavelet coefficients; wavelet transforms; Color; Data compression; Discrete wavelet transforms; Filter bank; Image coding; Mirrors; Quantization; Spline; Wavelet coefficients; Wavelet transforms;
Journal_Title :
Image Processing, IEEE Transactions on