Overcoming superstrictness in line drawing interpretation

Abstract

Presents an algorithm for correcting incorrect line drawings-incorrect projections of a polyhedral scene. Such incorrect drawings arise, e.g., when an image of a polyhedral world is taken, the edges and vertices are extracted, and a drawing is synthesized. Along the way, the true positions of the vertices in the 2D projection are perturbed due to digitization errors and the preprocessing. As most available algorithms for interpreting line drawings are "superstrict," they judge these noisy inputs as incorrect and fail to reconstruct a three-dimensional scene from them. The presented method overcomes this problem by moving the positions of all vertices until a very close correct drawing is found. The closeness criterion is to minimize the sum of squared distances from each vertex in the input drawing to its corrected position. With this tool, any superstrict method for line drawing interpretation is now practical, as it can be applied to the corrected version of the input drawing.