Robust Content-Dependent Photometric Projector Compensation

Abstract

We wish to compensate for irregularities in the output of digital projectors that occur when they are used in non-ideal situations, such as those with varying surface reflectance and ambient light. We transform the image to be displayed into a compensation image that will produce the desired appearance. In contrast to previous methods, the transformation is based on both a radiometric model of the system and the content of the image. We present a five-stage framework for performing content-dependent photometric compensation, and the details of a specific implementation. The original image is converted to a perceptually-uniform space, the desired chrominance is fitted to the gamut of the projector, a luminance range is calculated within which the fitted chrominance values can be produced, the original luminance is fitted to that range, and finally the fitted values are converted to a compensation image. Our method balances strict compensation against dynamic range in the final output, so we can produce a good result even when removal of all visible spatial variation is not possible.