Affine-invariant contour tracking with automatic control of spatiotemporal scale

A framework for visual tracking of contours is presented, based on a synthesis of elastic models, stochastic filtering, and geometric invariance. Flexibly coupled curve templates implement soft prior assumptions about shape. Affine invariance, built into the flexible coupling, ensures that the affine deformations that arise naturally from image projection are favored. The stochastic basis of the framework is shown to result naturally in an automatic mechanism for the control of spatiotemporal scale