Optimizing Content-Preserving Projections for Wide-Angle Images
Robert Carroll, Maneesh Agrawala, Aseem Agarwala
Abstract
Any projection of a 3D scene into a wide-angle image unavoidably results in distortion. Current projection methods either bend straight lines in the scene, or locally distort the shapes of scene objects. We present a method that minimizes this distortion by adapting the projection to content in the scene, such as salient scene regions and lines, in order to preserve their shape. Our optimization technique computes a spatially-varying projection that respects user-specified constraints while minimizing a set of energy terms that measure wide-angle image distortion. We demonstrate the effectiveness of our approach by showing results on a variety of wide-angle photographs, as well as comparisons to standard projections.
Wide-angle photographs can appear badly distorted under existing projections, such as the perspective, Mercator and stereographic projections. Perspective projection preserves linear structures in the scene, but distorts shapes of objects. Mercator and stereographic projections preserve shapes locally, but bend linear structures. Our projection is designed to both preserve local shape and maintain straight scene lines that are marked by the user with our interactive tool.