Projecting a single sharp image across a curved surface has traditionally required considerable work. New software from the Fraunhofer Institute for Computer Architecture and Software Technology, FIRST, is designed to calibrate the required projectors automatically so that their images align to the pixel. Researchers will present the system at IBC in Amsterdam from 7 to 11 September 2007.
Planetariums and dome cinemas create immersive viewing environments, but films and shows on curved surfaces require multiple coordinated projectors to generate a seamless image. Individual projectors are normally adjusted by hand, or their images are distorted electronically until they match. Both methods are time-consuming and inflexible because projector positions cannot subsequently change. The FIRST system automatically calibrates the projectors and aligns their images pixel-accurately, supporting synchronised projection on surfaces of arbitrary shape.
“The calibration software first receives data describing the screen geometry, the number and positions of the projectors, and their approximate alignment,” said Ivo Haulsen of FIRST. Digital cameras record the positions of the images on the screen. Image-recognition algorithms then distort and fit the individual images to the projection surface automatically, creating a high-resolution, seamless composite. FIRST described the autocalibration software as fast and flexible; if a projector moves, its image can be reintegrated into the overall display quickly.
The technique can control almost any display device, including specialist systems such as Carl Zeiss planetarium projectors or Sony’s 4K digital-cinema projector. FIRST identified cinemas, surround cinemas, planetariums, theme parks, events, trade fairs, and product presentations as potential applications.
The system also integrates playback technology. Its “Showplayer” combines films, still images, text banners, and live recordings into a show and can control external devices such as fog machines. Content is assembled and output in real time, avoiding a lengthy prerender before full-quality playback and allowing late changes. At resolutions up to 4K × 4K, it can also avoid separate slicing of image data across several projectors because the partial images are generated during playback. The institute will demonstrate the system on a wave-shaped surface at the Fraunhofer joint stand 8.381 in IBC Hall 8.
