Color consistency for digital multi-projector stereo display systems

摘要

Digital projectors have a significant advantage over CRTs for IPT setups: brightness. But they also have a number of disadvantages, one of which is color consistency. This problem is exacerbated when using the Infitec method for stereo separation, which in itself has some strong advantages for CAVE and tiled wall setups. In this paper we will describe a method for color and brightness correction of multi-projector display systems. The method itself is used in two new projection systems, which are currently under construction at Fraunhofer-IGD: The HEyewall and the Digital CAVE. The HEyeWall is the first stereo capable tiled display worldwide. The Digital CAVE is the first CAVE with digital projectors and stereo separation based on Infotec(tm). In this paper we present these new IPTs in more detail and also present our experience with digital projectors.To calibrate all the involved projectors photometric measurements of the different projectors are used to calculate a common gamut in a linear colorspace. Input colors are mapped into this gamut and from there mapped into the individual projector's colorspace. This method allows to adjust the rendering output of two or more projectors with different color gamuts in such a way that the projected images are photometrically calibrated. Since the correction has to be done for each pixel, a straightforward implementation would be very slow and far away from realtime. Consequently we will outline a method how to improve performance and overcome this limitation.