  We describe the Mediatrix filamentation method, an iterative procedure that
decomposes image shapes in filaments over their intensity ridgeline along their
main direction using perpendicular bisectors. From this decomposition several
morphological features can be derived, such as the length along the main
direction and thickness of the object and, for curved objects, estimates of its
center of curvature and curvature radius. As an example, we apply this
technique to arc-shaped objects: simulated gravitational arcs.
