Image Precision Silhouette Edges
Author(s): Ramesh Raskar, Michael F. Cohen.
Proceedings: Symposium on Interactive 3D Graphics (I3D'99), pp. 135--140, Atlanta, Georgia, United States,
1999.
[BibTeX] [DOI] 
Abstract:
Finding and displaying silhouette edges is important in
applications ranging from computer vision to nonphotorealistic
rendering. To render visible silhouette edges of a polygonal
object in a scene from a given viewpoint, we must first find all
silhouette edges, i.e. boundaries between adjacent front facing
and back-facing surfaces. This is followed by solving the partial
visibility problem so that only those parts of silhouette edges,
which are not occluded by interior of any front facing surface,
are rendered. The scene may optionally be rendered with a
lighting model. This paper describes a simple general-purpose
method to combine all three operations for any scene composed
of objects that can be scan-converted. Using a depth buffer, the
rendering process computes the intersection of adjacent front
facing and back-facing surfaces in image space at interactive
rates. All operations are performed in image-precision and
hence special care is taken for the limited numerical precision
of the depth buffer. A solution is suggested using viewdependent
modification of polygonal objects. The method does
not require any preprocessing or adjacency information and
hence is applicable for dynamic scenes.