Abstract:

NURBS is suitable for mainstream and general surface design. In order to ensure the smoothness of optical progressive lens and keep its sphericity unchanged by partial modification, an optimization algorithm based on NURBS reconstruction technique is proposed. Because NURBS surface has good local modification and invariance under affine and perspective changes, the research method of using NURBS to reconstruct the optical lens and define the partial modification of the surface is selected. Through preprocessing, the shape value points on the lens are obtained, and a three-time NURBS surface reconstruction algorithm based on the reverse control points is designed. The basic concepts are defined, and the selection of shape value points is solved, the control points are solved by quadratic method, the surface re-fitting and the local modification are also defined. The effectiveness of the algorithm in this study is verified by experiments.

Key words: progressive lenses, NURBS, free-form surface, reconstruction technique, inverse calculation, partial modification, evaluation of the lens, FFV simulation