Immersive planar display using roughly aligned projectors

When a projector is oblique with respect to a planar display surface, it creates keystoning and the projected image is distorted. We present a rendering technique to display perspectively correct images for a moving user. This allows using roughly aligned projectors and eliminates the need for frequent electro-mechanical adjustments. The rendering process has no additional cost and can be implemented with traditional graphics hardware. We compute the collineation induced due to the display plane during preprocessing. The main idea of the paper is to use this collineation to render and warp the images of 3D scenes in a single pass via approximation of the depth buffer. We also describe how this method can be extended to display systems with multiple overlapping projectors. This technique can be easily used in CAVE, Immersive Workbenches and PowerWalls.