Reconstruction of objects with jagged edges through Rao-Blackwellized fitting of piecewise smooth subdivision curves

Abstract

In some applications objects are known to have non-smooth or "jagged" edges, which are not well approximated by smooth curves. We use subdivision curves as a simple but flexible curve representation, which allows tagging corners to model non-smooth features along otherwise smooth curves. A Markov chain Monte Carlo approach yields an approximate posterior distribution over tags, while Rao-Blackwellization allows us to integrate out the control point locations by an approximation. We apply this general methodology to multi-view reconstruction of piecewise smooth curves from multiple calibrated views in which the object has been segmented from the background. Results are shown for multiple images of two pot shards as would be encountered in archaeological applications.