Abstract: An image representation using a structured object may be readily manipulated by a computer. This image representation can represent more complex images where the structured object defines a boundary for which image values near the boundary in a region are defined by a function called an edge characteristic function. The edge characteristic function is applied by determining, for each point in the region, a point on the boundary to which the given point is closest, herein called an anchor, and a distance to that point. Different edge characteristic functions may be assigned to different points along the boundary. In one embodiment, edge characteristic functions are assigned to selected characteristic points on the boundary. These edge characteristic functions may be interpolated to provide edge characteristic functions for remaining points along the boundary.