Selection of Optimal Spectral Sensitivity Functions for Color Filter Arrays

Typical consumer-level digital cameras use color filter arrays (CFA) overlaid on the optical sensor such that only one color is sampled at a particular spatial location. The full color image required for display is reconstructed from the sub-sampled data in an interpolation step commonly referred to as demosaicking. We present a method to select optimal color filter responses that minimizes both spatial reconstruction and color reproduction errors in a perceptually uniform color space. Optimal sensitivities for a three-color Bayer-type CFA and a four-color CFA are obtained and found to perform significantly better than RGB and CMY color filters in terms of the S-CIELab error metric.