Spectral sensitivity optimization of color image sensors considering photon shot noise: four-channel sensor models
Hideyasu Kuniba · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2009
Four channel sensors were evaluated with a image sensor model and their performance was compared with three channel sensors considering both color reproduction accuracy and photo shot noise. When noise was not considered, a sensor with usual RGB plus an additional channel which resided between G and B was the best. But when the emphasis was on noise, a sensor with B, R and two Gs was the best because reducing noise of G should be effective in reducing noise of all L*a*b* components. Bayer color filter array (CFA) samples twice density of G than R or B. This CFA is considered to be efficient in resolution but the result suggests it is also efficient in SNR. Comparing to three channel sensors, the four channel sensors were better in color reproduction but worse in noise. An image preference model proposed by Kuniba and Berns was used to evaluate them and it was shown that neither one was superior than the other.