Reconstruction from sketched drawings

Abstract

The earliest works on the interpretation and reconstruction of drawings as 3D objects concern the interpretation of polyhedral objects, that is, drawings depicting solid bodies which are bound by a finite number of planar faces. The line drawing is, therefore, a projection of the polyhedron onto the picture plane. In such drawings, a line segment corresponds to the edges formed by the intersection of two faces while junctions correspond to the vertices of these edges. Each junction, therefore, represents a point which is shared by two or more faces of the polyhedron. The reconstruction problem can then be posed as the problem of determining the equations of the object planes, using the junction points to define a system of linear equations as shown in Figure 4.1. Solving this system of linear equations provides the missing depth coordinate of each junction point. [extract].