ShadowCast effectiveness on complex terrain

Determine whether the segmentation benefits of ShadowCast extend to complex terrain with substantial elevation variations, where terrain slope, terrain-cast shadows, slope-induced darkness, and relief displacement can invalidate fixed-distance mask translation and brightness-based direction estimation.

Background

ShadowCast was evaluated on benchmarks dominated by relatively flat scenes and assumes that the ground around elevated objects is flat. In hilly or mountainous terrain, shadow geometry depends on slope, terrain itself may cast shadows, surface brightness may be caused by slope rather than shadow, and relief displacement can separate object masks from the locations where shadows begin.

The authors note that ShadowCast has not been evaluated under substantial elevation variation and explicitly leave its effectiveness in such settings unresolved. A physically based alternative would require additional inputs such as a height map and sun position, which are not used by the proposed augmentation.