Contour Shape Analysis Using Crystalline Flow 2001.Nov.7
Crystalline Flow Evolution of a polygon
Crystalline Flow Outward Normal Velocity depends on Nonlocal Weighted Curvature
Curvature Inscribing Circle Wulff Shape
A Convex m-Polygon
Wulff Shape A Set of Unit Vectors:
Admissible Crystal A simple Polygon All outward normals belong to The normal of adjacent facet is parallel to the normal adjacent in the Wulff Shape Admissible Wulff Shape Not Admissible Jump!
Crystalline Flow : Nondecreasing in 2nd variable: Transition Number 0+1 : Length of facet of Wulff Shape: Length of i-th facet Nonlocal Curvature
Crystalline Flow Facet Disappearing at t = T* Case A: The polygon becomes convex near T* and all facet disappear at T*. All facets disappear at t = T*.
Crystalline Flow Facet Disappearing at t = T* Case B: Two parallel facets meet together.
Crystalline Flow is locally Lipschitz on is nondecreasing on for all Case B does not occur if
Crystalline Flow Facet Disappearing at t = T* Case C: At most two consecutive facets disappear.
Crystalline Flow
Crystalline Flow
Chain Coded Contour Make given polygon Admissible
Crystalline Flow
Scale Space Analysis Facet Number in Original Time White: Convex Black: Concave
Facet Extraction Trace concave(convex) facets back to t=0. Extraction Scale Extracted Facets
Facet Extraction As the extraction scale increases, more important facets are extracted.
Facet Extraction
Conclusions Crystalline for Contour Shape Analysis Wulff Shape Selection!