Accession Number : ADP001209

Title :   The Theory of Straight Homogeneous Generalized Cylinders,

Corporate Author : CARNEGIE INST OF TECH PITTSBURGH PA DEPT OF COMPUTER SCIENCE

Personal Author(s) : Shafer,Steven A. ; Kanade,Takeo

Report Date : JUN 1983

Pagination or Media Count : 9

Abstract : In recent years, Binford's generalized cylinders have become an important tool for imagine understanding. However, research has been hampered by a lack of analytical results for these shapes. In this paper, a definition is presented for Straight Homogeneous Generalized Cylinders, those generalized cylinders, with a straight axis and with cross-sections which have constant shape but vary in size. This class of shapes, while still quite large, has properties which make considerable analysis possible. The results begin with deriving formulae for points and surface normals for these shapes. Theorems are presented concerning the conditions under which multiple descriptions can exist for a single solid shape. Then projections and contour generators are analyzed for some subclasses of shapes. The strongest results are obtained for solids of revolution (which the authors name Right Circular SHGCs), for which a closed-form method for analyzing image contours is presented. It is seen that a picture of the contours of a solid of revolution is ambiguous, with one degree of freedom related to the angle between the line of sight and the solid's axis. (Author)

Descriptors :   *Image processing, *Cylindrical bodies, *Optical cross sections, *Coordinates, Axes, Homogeneity, Shape, Sizes(Dimensions), Variations, Contours, Silhouettes, Line of sight, Tangents

Distribution Statement : APPROVED FOR PUBLIC RELEASE