1. A method for tracking a non-rigid object in a video, comprising for each frame in the video, the steps of: estimating a motion transition contour model of the object; assigning normal lines to the motion transition contour model; constructing a posterior deformation probability map according to the normal lines; detecting a deformed contour of the object according to the posterior deformation probability map; obtaining a point distribution model for a generic contour-subspace; projecting the deformed contour of the object onto a contour-subspace according to the point distribution model; and regulating the projected contour.