M. Hereld and R. L. Stevens, "Pixel-Aligned Warping for Multi-Projector Tiled Displays," Preprint ANL/MCS-P1237-0305, March 2005. [pdf]
Multi-projector tiled displays offer a scalable path to high-resolution display systems, often in a large format. Such displays have been employed in a range of applications from scientific visualization to collaborative virtual environments. Images projected onto these systems have always looked less sharp than expected owing to the image warping that is required to achieve geometrical alignment of the partial images to form the seamless whole. Similar degradation of image quality accompanies keystone correction techniques and image warping onto non-planar surfaces used in single projector applications. In this paper we discuss the underlying cause of the degradation of apparent image resolution and we introduce a new class of warping techniques, called pixel-aligned warping, that tend to preserve image sharpness at the expense of strict adherence to underlying geometrical constraints that define the desired warp. We demonstrate how such techniques can be used to significantly improve the apparent sharpness of the final image.