OBJECTIVE: The algorithm of Watersnakes is used to segment the hippocampus on one slice of MR image.

METHODS: This method integrates the watershed transform and the active contour algorithm. The watershed transform, based on mathematical morphology, is powerful and flexible for segmentation. However, it does not allow the characteristics of region boundaries to be included into the way that active contour algorithm do. So, oversegmentation is in the result, even to hippocampus. For watersnakes algorithm, the primitive contour of hippocampus can be obtained using watershed transform. Based on energy-driven, the contour of hippocampus develops into the ultimate result. In the process of energy-driven, the information relating to characteristics of region boundaries is involved.

RESULTS: The results of watersnakes showed oversegmentation could be avoided, compared to the results of watershed transform.

CONCLUSION: Watersnakes can use the advantage of watershed transform and active contour algorithm to improve the results of segmentation.