Universal Demosaicking of Color Filter Arrays
Modern Color Filter Array (CFA) designs avoid overlap of luminance and chrominance spectra as it is widely believed to cause irreversible crosstalk and aliasing. In this paper, we present a simple formulation of the demosaicking problem that disregards spectral overlap - and thus the geometry of the spectra - and instead connects the luminance and chrominance resolutions in a more fundamental way to the photosite density of the sensor. A linear universal demosaicker consisting of space variant filters results from this formulation along with CFA designs that capture more image information than competing designs. This includes the interesting class of random RGB designs that outperform the Bayer CFA with nonlinear demosaickers in terms of PSNR and have a number of additional desirable properties. Furthermore, we present non-linear enhancements to our universal demosaicker and show them to be either related to compressive sensing or an alternate reconstruction algorithm for it.