Edge detection in images has been a fundamental problem
in computer vision from its early days. Edge detection
on surfaces, on the other hand, has received much less attention.
The most common edges on surfaces are ridges
and valleys, used for processing range images in computer
vision, as well as for non-photorealistic rendering in computer
graphics. We propose a new type of edges on surfaces,
termed relief edges. Intuitively, the surface can be considered
as an unknown smooth manifold, on top of which a
local height image is placed. Relief edges are the edges of
this local image. We show how to compute these edges from
the local differential geometric surface properties, by fitting
a local edge model to the surface. We also show how the
underlying manifold and the local images can be roughly
approximated and exploited in the edge detection process.
Last but not least, we demonstrate the application of relief
edges to artifact illustration in archaeology.