Fast (Spherical) Light Field Rendering with Per-Pixel Depth

Image-based rendering techniques are a powerful alternative to traditional polygon-based computer graphics. This paper presents a novel light field rendering technique which performs per-pixel depth correction of rays for high-quality reconstruction. Our technique stores combined RGB and depth values in a parabolic 2D texture for every light field sample acquired at discrete positions on a uniformly sampled sphere. Image synthesis is implemented on the GPU as a fragment program which extracts the correct image information from adjacent cameras for each fragment by applying a per-pixel depth correction of rays. We show that the presented image-based rendering technique provides a significant improvement compared to previous approaches. We explain two different rendering implementations which make use of a uniformly sampled parameterisation to minimize disparity problems and ensure full six degrees of freedom for virtual view synthesis. While one rendering algorithm implements a run-time efficient iterative refinement approach for rendering light fields with per pixel depth correction the other approach employs a raycaster for per pixel depth correction and provides superior rendering quality at moderate frame rates. GPU based per-fragment depth correction of rays, used in both implementations, reduces ghosting artefacts to a non noticeable amount and provides a rendering technique that performs without exhaustive pre-processing for 3D object reconstruction or real-time ray-object intersection calculations at rendering time.