| Popis: |
Listless SPECK (LSPECK) is a low complexity image coding algorithm compared to SPECK. The problem of LSPECK is that, it encode each insignificant subband by a zero. Therefore, these block based coders codes as many zeros as the number of insignificant subbands. This gives rise to many zeros at the encoder output on early bit plane passes. By looking at the statistics of transformed images, the number of significant coefficients at some of the higher bitplanes are likely to be very few. We propose a variant of LSPECK algorithm, called as Improved LSPECK (ILSPECK), that code a single zero to several insignificant subbands. This reduces the length of the output bit string as well as encoding/decoding time. Further, ILSPECK algorithm is coupled with discrete tchebichef transform (DTT). The propose new coder called as Hierarchical Listless DTT (HLDTT), preserves most of the properties of wavelet coders. Extensive simulations on various kind of images shows the effictiveness of our coder. |
