1. A method for reconstructing-three-dimensional (3D) lines in a 3D world coordinate system from two-dimensional (2D) lines in a single image of scene, comprising the steps of: detecting and clustering the 2D lines using vanishing points; generating a constraint graph of vertices and edges, wherein, the vertices represent the 2D lines, and the edges represent constraints on the 2D lines; identifying the constraints on the 2D lines that are satisfied on the 3D lines; and reconstructing, the 3D lines in the 3D world coordinate system using the identified constraints.