An Invited Paper for the
International Symposium on Circuits and Systems
Predictive Shape Coding Using Generic Polygon Approximation
Brian L. Evans
Department of Electrical and Computer Engineering,
Engineering Science Building,
The University of Texas at Austin,
Austin, TX 78712-1084 USA
We introduce an efficient, MPEG-4 compliant, predictive binary shape coding
method that consists of (1) global motion estimation,
(2) local motion estimation, (3) matched segment coding, and
(4) residual segment coding.
Global and local motion estimation use contour pel matching and
knowledge of previously reconstructed contours.
After motion compensation, we code the one-dimensional reference contour
indices of the matched contour positions.
The final step codes the mismatched contour segments using residual coding.
We use a maximum shape distortion tolerance parameter (dmax),
which is zero for lossless coding, for both motion estimation and residual
We apply the new shape coding method to MPEG-4 binary mask test
sequences in QCIF and SIF formats for a wide range of dmax values.
The key contribution of our method is in lossy shape coding in which the
average coding gain is more than 100% over generalized differential
The full paper is available in
Last Updated 11/08/04.