Abstract: This article focuses on real-time image correction techniques that enable projector-camera systems to display images onto screens that are not optimized for projections, such as geometrically complex, coloured and textured surfaces. It reviews hardware-accelerated methods like pixel-precise geometric warping, radiometric compensation, multi-focal projection and the correction of general light modulation effects. Online and offline calibration as well as invisible coding methods are explained. Novel attempts in super-resolution, high-dynamic range and high-speed projection are discussed. These techniques open a variety of new applications for projection displays. Some of them will also be presented in this report.