Consistency and Correction of Line-Drawings, Obtained by Projections of Piecewise Planar Objects

This paper deals with line-drawings, obtained from images of piecewise planar objects after edge detection. Such images are used e.g. for navigation and recognition. In order to be a possible image of a three dimensional piecewise planar object, it has to obey some projective conditions. Criteria for a line-drawing to be correct is given in this paper, along with methods to find possible interpretations. If there are many objects in the scene there may be occlusions between objects. There may also be occlusions between different parts of the same object. A method that can handle such occlusions is presented