DottyToto: a measurement engine for aligning multiprojector display systems

Tiled displays systems built by combining the images from arrays of projectors can provide huge numbers of pixel elements to applications needing to visually represent lots of information. Such applications are already coming into wide usage and include large scientific visualizations, collaborative virtual environments, and rich multimedia spaces. It is, however, difficult to create the illusion of a unified seamless display for a variety of reasons including optical distortion of the individual projector images due to imperfections in the lenses and basic alignment of the projectors. In this paper we describe an efficient and optimized measurement process using inexpensive components that is tolerant of a wide range of imperfections in components and measurement setup (lighting conditions, camera optics, etc.). Our method nonetheless is capable of accurate and detailed measurement of the layout of all projector images, including the generation of a detailed model of the distortions in each projector optical system. It performs these measurements on the entire array of projectors at once. Once the detailed mapping between projector pixels and mural pixels is measured, the resulting relations can be used in any of a number of ways to improve the appearance of images projected on the display.