臺灣博碩士論文加值系統

浮現式零樹小波編碼 (Embedded Zerotree Wavelet; EZW)已經被證實在
漸進式影像壓縮方面有很好的效果。為了加強EZW編碼對抵抗錯誤的強韌
性﹐可以採用小波係數分組的方式﹐並將各群組分別獨立用EZW作編碼﹐
使錯誤不至於蔓延至整張影像。在本論文中﹐我們更進一步地應用錯誤隱
藏的技術以增強此抗錯性EZW系統之重建影像的品質﹔我們採用小波域係
數之錯誤隱藏方法﹐錯誤之係數以周圍正確之係數內插而得。實驗結果顯
示當錯誤發生在壓縮位元流之較前端時﹐此種的錯誤隱藏方法可以明顯的
增進重建影像的品質。

The embedded zerotree wavelet (EZW) coding hasshown great
performance in progressive image coding. To enhance the error
robustness of EZW, grouping technique is applied which divided
the wavelet coefficients into many groups and each group was EZW
encoded independently. In this work, we further improve the
quality by applying error concealment techniques to the error-
resilent EZW coding.We perform the concealment in the wavelet
domain. The simulation results show a significant improvement in
the reconstructed image quality when error occur in the early
part of the compressed data stream.