Progressive Transmission in Trellis Coded Quanitization-Based Image Coders

We have shown that wavelet-TCQ image coders can be conngured to support hierarchical and progressive modes analogous to those speciied by the JPEG standard. These modes can be supported with little or no loss in coding eeciency. We have shown that a relatively simple entropy coder combined with a sophisticated quantizer results in a image coder with PSNR performance similar to that achieved using a simple quantizer and sophisticated entropy coder. 6. REFERENCES 1] A. Said and W.A. Pearlman, \A new fast and ee-cient image codec based on set partitioning in hierarchical trees", IEEE Transactions on Circuits and encoded sequence has been received. The signed integer consisting of the bits that have been received so far is multiplied by twice the step size to approximate the inverse TCQ operation. When the bits for an entire sequence are received, the full inverse TCQ operation is performed on that sequence. 4. CODER PERFORMANCE We have compared the performance of the presented system using diierent rate allocation schemes and en-tropy coders. We constructed four diierent architec-tures, namely, OTA (Optimum step sizes / TCQ / Arithmetic bitplane coder), CTA (Constant step sizes / TCQ / Arithmetic bitplane coder), OTS (Optimum step sizes / TCQ / SPIHT coder), and CTS (Constant step sizes / TCQ / SPIHT coder). Figure 4 compares the PSNR performance of these systems on Goldhill. All coders use the (9,7) biorthogonal lter bank of 9] and have 3 levels of uniform decomposition, followed by 2 more levels of dyadic decomposition of the reference band (\3+2"). Our tests show that OTA performs better than the other algorithms.