High Resolution Photography with an RGB-Infrared Camera

Abstract

A convenient solution to RGB-Infrared photography is to extend the basic RGB mosaic with a fourth filter type with high transmittance in the near-infrared band. Unfortunately, applying conventional demosaicing algorithms to RGB-IR sensors is not possible for two reasons. First, the RGB and near-infrared image are differently focused due to different refractive indices of each band. Second, manufacturing constraints introduce crosstalk between RGB and IR channels. In this paper we propose a novel image formation model for RGB-IR cameras that can be easily calibrated, and propose an efficient algorithm that jointly addresses three restoration problems - channel deblurring, channel separation and pixel demosaicing - using quadratic image regularizers. We also extend our algorithm to handle more general regularizers and pixel saturation. Experiments show that our method produces sharp, full-resolution images of pure RGB color and IR.