viewpoint from occluding contour开题资料.pdf

CVGIP: IMAGE UNDERSTANDING
Vol. 55, No. 2, March, pp. 198-211, 1992
Viewpoint from Occluding Contour
W. BRENT SEALES*
Computer Science Department, University of Kentucky, Lexington, Kentucky 40536
AND
CHARLES R. DYER
Computer Science Department, University of Wisconsin, Madison, Wisconsin 53706
Received October 2, 1991; revised November 20, 1991
set of occluding contours in a single image. The precom-
In this paper we presentthe geometryand the algorithmsfor puted model of how the contour can appear provides a
organizing a viewer-centeredrepresentation of the occludingcon- set of constraints in viewpoint since the contour itself is
tour of a polyhedron. The contour is computedfrom a polyhedral directly dependent upon viewing direction. Although fea-
boundary modelas it would appearunder orthographicprojection tures of the occluding contour are strongly tied to view-
into the image plane from every viewpoint on the view sphere. point, they have largely been ignored because of diffi-
Usingthis representation,we showhow to derive constraintson culty in representation.
regionsin viewpoint spacefrom the relationshipbetween detected The occluding contour is the projection in the image of
imagefeatures and our precomputedcontour model. Such con-
the points on a smooth surface where the visual direction
straintsare basedon both qualitative (viewpoint extent) andquan-
titative (angle measurementsand relative geometry)information is tangent. Much of the geometry associated with the
that has been precomputed about how the contour appears in the occluding contour and its pr