Abstract
Two important issues of shape from contour research are addressed in this dissertation. The first is the imperfection of input data and the second is the completeness of output models. We present a solution that is based on the analysis of possible configurations of imperfect line drawings and the implementation of a complete rule based system. Constraints imposed by 2D line drawing and heuristics of human visual perception are formulated into production rules and these rules work interactively to reason complete 3D object models from a single imperfect line drawing.A nonmonotonic forward reasoning mechanism is realize by using the Truth Maintenance System (TMS). The TMS is used to maintain a dependency network of currently active facts for reasoning in hypothetical situations. It also leads to an effective way to backtrack an assumption to resolve contradictions which is called Dependency Directed Backtracking (DDB).The ability of the system to tolerate the imperfection of input data makes it possible for the system to deal with real data extracted from real images. And the complete reconstruction of 3D object models is obviously useful for a variety of applications, including object recognition, classification and manipulation, target tracking etc.