Real-time image-based rendering for stereo views of vegetation

Rendering of detailed vegetation for real-time applications has always been difficult because of the high polygon count in 3D models. Generating correctly warped images for nonplanar projection surfaces often requires even higher degrees of tessellation. Generating left and right eye views for stereo would further reduce the frame rate since information for one eye view cannot be used to redraw the vegetation for the other eye view. We describe an image based rendering approach that is a modification of an algorithm for monoscopic rendering of vegetation proposed by Aleks Jakulin(1). The Jakulin algorithm pre-renders vegetation models from 6 viewpoints; rendering from an arbitrary viewpoint is achieved by compositing the nearest two slicings. Slices are alpha blended as the user changes viewing positions. The blending produces visual artifacts that are not distracting in a monoscopic environment but are very distracting in a stereo environment. We have modified the algorithm so it displays all pre-rendered images simultaneously and slicings are partitioned and rendered in a back-to-front order. This approach improves the quality of the stereo, maintains the basic appearance of the vegetation and reduces visual artifacts but it increases rendering time slightly and produces a rendering that is not totally faithful to the original vegetation model.