Tiled 360° panoramic projection system

In order to obtain 360 degree panoramic displays, tiled video projections are often used. In this paper we present a system for cylindrical 360 degree panoramic projection based on a client-server architecture. The system performs following actions: projector calibration, image transformation and video playback. To perform above actions several problems have to be addressed. Calibration of multiple projectors is based on computing of spatial relations between cylindrical projecting surface and each projector. We do this by photographing the projected chessboard pattern of each projector using a camera with fish-eye lens. The photograph first has to be unwrapped into a rectangle shaped texture. After that, the relation between original chessboard corners and corners on the photograph has to be found. Using these corners the image transformation function has to be interpolated. The transformation of image to be projected is done using this function and also includes lightning correction to achieve smooth transitions between each projector image. If playing video, videos from all projectors have to be synchronized. In the current client-server architecture, a server performs semiautomatic projector calibration, files and configuration distribution to clients and has the ability to off-line create images for each projector. Each client handles storage, showing of already prepared images and playback and real-time transformation of videos. The projector calibration is done using Matlab, whilst the playback and real-time transformation of video is done using custom made software written in C++ and OpenGL.