Rate-distortion optimal skeleton-based shape coding

We present a new shape-coding approach, which decouples the shape information into two independent data sets, the skeleton and the distance of the boundary from the skeleton. The major benefit of this approach is that it allows a more flexible trade-off between accuracy of the approximation and bit-allocation cost, and thus, provides the possibility of better performance in the operational rate-distortion (ORD) optimal sense than other reported techniques. The characteristics of these data sets are studied and various approximation approaches are applied on each of them to reach an ORD optimal result. We apply, for example, polygonal approximation on both the skeleton and distance data. We demonstrate that the resulting approach outperforms existing ORD optimal approaches.