MACHINE PERCEPTION OF THREE-DIMENSIONAL SOLIDS,

In order to enable a computer to construct and display a three-dimensional array of solid ob jects from a single two-dimensional photograph, the rules and assumptions of depth perception have been carefully analyzed and mechanized. It is assumed that a photograph is a perspective projection of a set of objects which can be con-structed from transformations of known three dimensional models, and that the objects are sup ported by other visible objects or by a ground plane. These assumptions enable a computer to obtain a reasonable, three-dimensional descrip tion froom the edge information in a photograph by means of a topological, mathematical process. A computer program has been written which can process a photograph into a line drawing, trans form the line drawing into a three-dimensional representation, and finally, display the three dimensional structure with all the hidden lines removed, from any point of view. The 2-D to 3-D construction and 3-D to 2-D display processes are sufficiently general to handle most collections of planar-surfaced objects and provide a valuable starting point for future investigation of com puter-aided three-dimensional systems. (Author)