這篇論文提出了一個有效率的方法來壓縮輪廓圖。這個方法架在鏈編碼的基礎上並運用了差分鏈編碼的觀念，差分鏈編碼的觀念在於如果使壓縮後的編碼集中在某個碼，對這些編碼再壓縮的效果就會很好，可以使得壓縮率提高。這篇論文應用了這些概念，提出了這個簡單的方法並且有著還不錯的壓縮率，其效果會和經過再壓縮的差分鏈編碼及MPEG-4裡壓縮輪廓的方法做比較並討論。

A simple but efficient technique for encoding object contour is presented. It is based on the chain coding representation and utilizes the benefit of differential chain coding (DCC) and entropy coding. DCC let the occurrences of symbols skewed. And the entropy coding let the frequently used symbols correspond to the short codes. This thesis proposes a simple DCC-based method to adaptively trace the contour direction locally and effectively select the code symbol accordingly. The method really alters the distribution of symbol occurrences to the extreme case, thus the gain of entropy code becomes significant. We conducted several experiments to compare with DCC with entropy coding and MPEG-4 shape coder. The experimental results show that this simple method is constantly better than DCC and comparable with the MPEG-4 shape code.

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