A contour-based method--improved Freeman chain coding is discussed. We compare code length,chain length,rolling operation,and whole chain bits with the traditional coding,and provide the results of comparison analysis.

• 通过对MPEG-4的研究探讨；提出一种基于边缘轮廓的形状编码方法:改进的Freeman链码法；将它与传统的链码方法从码长、链码长度、是否独立于旋转操作、链码总位数四个方面进行了比较；给出比较分析结果.