A Projection System with Radiometric Compensation for Screen Imperfections

A major limitation of existing projection display systems is that they rely on a high quality screen for projecting images. We believe that relaxing this restriction will make projectors more useful and widely applicable. The fundamental problem with using an arbitrary surface for a screen is that the surface is bound to have its own colors and textures (bricks of a wall, painting on a wall, tiles of a ceiling, grain of a wooden door, etc.) or surface markings (paint imperfections, scratches, nails, etc.). As a result, when an image is projected onto the surface, the appearance of the image is modulated by the spatially varying reflectance properties of the surface. Humans are very sensitive to such modulations. In this paper, we present a method that enables a projector to display images onto an arbitrary surface such that the quality of the images is preserved and the effects of the surface imperfections are minimized. Our method is based on an efficient off-line radiometric calibration that uses a camera to obtain measurements from the surface corresponding to a set of projected images. The calibration results are then used on-line to compensate each display image prior to projection. Several experimental results are shown that demonstrate the advantages of using our compensation method.