Linear universal demosaicking of regular pattern color filter arrays

We show that a recently developed universal demosaicker by the present authors greatly outperforms existing demosaickers when tested with a realistic optical pipeline. We present speed and quality optimizations of this demosaicker for the case of regular pattern color filter arrays. We implement and extensively test optimized versions for several common CFAs including Bayer, CMY and several RGBW patterns. These tests show that the proposed algorithms outperform other demosaickers by a substantial margin while being faster than most of them. High sensitivity RGBW CFAs are shown to have better performance than Bayer demosaicked with previous algorithms. The proposed universal demosaicker is a set of Finite Impulse Response Filters, which allows a single, efficient, Image Signal Processor design to support different CFAs by changing its filter weights. Being linear, the demosaicker is free of noise induced artifacts and outputs images with near Poissonian noise which is noise reduction friendly.