Influence of Spectral Sensitivity Functions on Color Demosaicing

Color images acquired through single chip digital cameras using a color filter array (CFA) contain a mixture of luminance and opponent chromatic information that share their representation in the spatial Fourier spectrum. This mixture could result in aliasing if the bandwidths of these signals are too wide and their spectra overlap. In such a case, reconstructing three-color per pixel images without error is impossible. One way to improve the reconstruction is to have sensitivity functions that are highly correlated, reducing the bandwidth of the opponent chromatic components. However, this diminishes the ability to reproduce colors accurately as noise is amplified when converting an image to the final color encoding. In this paper, we are looking for an optimum between accurate image reconstruction through demosaicing and accurate color rendering. We design a camera simulation, first using a hyperspectral model of random color images and a demosaicing algorithm based on frequency selection. We find that there is an optimum and confirm our results using a natural hyperspectral image.