Exploiting temporal correlation in shape coding
This paper investigates ways to explore the between frame correlation of shape information within the framework of an operationally rate-distortion (ORD) optimal coder. Contours are approximated both by connected second-order spline segments, each defined by three consecutive control points, and by segments of the motion-compensated reference contours. Consecutive control points are then encoded predictively using angle and run temporal contexts. We utilize a novel criterion for selecting global object motion vectors, which further improves efficiency. Formulating this problem as Lagrangian minimization, we employ an iterative technique to remove dependency on a particular VLC and jointly arrive at the ORD optimal solution and its underlying conditional parameter distribution.