Active Contours without Edges-英文文献.pdfVIP

266 IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 10, NO. 2, FEBRUARY 2001 Active Contours Without Edges Tony F. Chan, Member, IEEE, and Luminita A. Vese Abstract—In this paper, we propose a new model for active con- the image (the external energy). Observe that, by minimizing tours to detect objects in a given image, based on techniques of the energy (1), we are trying to locate the curve at the points curve evolution, Mumford–Shah functional for segmentation and of maxima , acting as an edge-detector, while keeping a level sets. Our model can detect objects whose boundaries are not necessarily defined by gradient. We minimize an energy which can smoothness in the curve (object boundary). be seen as a particular case of the minimal partition problem. In A general edge-detector can be defined by a positive and de- the level set formulation, the problem becomes a “mean-curvature creasing function , depending on the gradient of the image , flow”-like evolving the active contour, which will stop on the de- such that sired boundary. However, the stopping term does not depend on the gradient of the image, as in the classical active contour models, but is instead related to a particular segmentation of the image. We will give a numerical algorithm using finite differences. Finally, we For instance will present various experimental results and in particular some examples for which the classical snakes methods based on the gra- dient are not applicable. Also, the initial curve can be anywhere in the image, and interior contours are automatically detected. where , a smooth