Digital cameras capture images through color filter array patterns and reconstruct the images using an appropriate demosaicking algorithm. CFAs usually contain three primary color filters. Since the panchromatic/ white filter receives less noise compared to the Red, Green and Blue filters, the CFA also can have additional white filters to reduce the noise impact on the reconstructed color image. Digital cameras only receive one color component at each pixel location through the CFA and the other unknown color components will be estimated using the demosaicking algorithm. In this paper, the RGBW-Bayer pattern has been studied, and appropriate adaptive and non-adaptive demosaicking algorithms have been provided for it. Also an optimized way will be presented to estimate the panchromatic filter output using red, green and blue color information. A modified demosaicking algorithm also has been presented for a new RGBW CFA, and the comparison between these two RGBW CFAs and the RGBw-Kodak CFA has been provided. The proposed algorithms have been tested on the Kodak sample images.
Mina Rafinazari, Eric Dubois, "Demosaicking algorithms for RGBW color filter arrays" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Color Imaging XXI: Displaying, Processing, Hardcopy, and Applications, 2016, https://doi.org/10.2352/ISSN.2470-1173.2016.20.COLOR-312