Joseph W. Longson

Stereo compositing accelerated by quadtree structures in piecewise linear and curvilinear spaces

We present a new stereoscopic compositing technique that combines volumetric output from several stereo camera rigs. Unlike previous multi-rigging techniques, our approach does not require objects rendered with different stereo parameters to be clearly separable to prevent visual discontinuities. We accomplished that by casting not straight rays (aligned with a single viewing direction) but curved rays, and that results in a smooth blend between viewing parameters of the stereo rigs in the user-defined transition area. Our technique offers two alternative methods for defining shapes of the cast rays. The first method avoids depth distortion in the transition area by guaranteeing monotonic behavior of the stereoscopic disparity function while the second one provides a user with artistic control over the influence of each rig in the transition area. To ensure practical usability, we efficiently solve key performance issues in the ray-casting (e.g. locating cell-ray intersection and traversing rays within a cell) with a highly parallelizable quadtree-based spatial data structure, constructed in the parameterized curvilinear space, to match the shape definition of the cast rays.