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.