Andy Tsai Anthony J. Yezzi William M. Wells III Clare M. Tempany Dewey Tucker Ayres C. Fan W. Eric L. Grimson Alan S. Willsky A Shape-Based Approach to the Segmentation of Medical Imagery Using Level Sets. 137-154 2003 22 IEEE Trans. Med. Imaging 2 db/journals/tmi/tmi22.html#TsaiYWTTFGW03 http://dx.doi.org/10.1109/TMI.2002.808355