Creating model of planar object from a single-perspective line drawing
Jun Chu, Mantun Gao, Guoding Chen · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2003
In this paper, a new approach for automatic creating boundary-representation of planar objects from single line drawings depicting the objects was proposed. Compared with other reconstruction methods that use information a bout points, for computer visiona nd CAD system, it was more convenient to use information about lines to interpret line drawings of polyhedral objects. The coordinates relations between a three-dimensional line and its perspective projection in two-dimension plane are given. Another three coordinates relations are also provided, namely, the coordinates relations when two lines are intersecting, parallel, cross, perpendicular, relations when a line is parallel with or belongs to a plane, and relations when two planes parallel each other. On the basis of these coordinates relations, some new constraints about lines and planes are proposed and a linear system is established. The 3D information of planar objects can be obtained by solving the linear system. In the interpretation of line drawing of a planar object, it is proved that there are at least four degrees of freedom. Some examples are given.