为了快速准确地进行图像分割，通过对现有分水岭变换算法的分析，并借鉴图像处理中常用的链码思想，提出了基于链码的分水岭变换算法，并首先扩展了传统链码的定义，将其分为指出链码和指入链码；然后提出并阐述了利用链码实现分水岭变换的两个性质；最后给出了基于链码的分水岭变换算法的具体描述，并详细分析了新算法的时间和空间复杂度。实验结果表明，新算法具有较低的时间和空间复杂度，且变换结果更有利于后续的图像理解。

For implementing image segmentation fast and accurately, and by analyzing the existing watershed transformation algorithms as well as considering the idea of chain code this paper presents a chain code based watershed transformation algorithm. In this paper, the traditional concept of chain code is first expanded into point out chain code and point in chain code. And then two characters, which depict how to make watershed transformation based on chain code are proposed and discussed. In the end, the detailed description of the chain code based watershed transformation algorithm is presented, and its complexity is analyzed in detail. The new algorithm is different from the traditional watershed algorithms, and it has two main steps: the first step is to generate point out and point in chain codes of every pixel by simulating raining, and the second step is to mark the labels of regions by simulating flooding. Experiments show that the new algorithm's time and space complexity is very low. Further more, such transformation result is more helpful for the following image understanding.