Color restoration for infrared cutoff filter removed RGBN multispectral filter array image sensor

Imaging systems based on multispectral filter arrays(MSFA) can simultaneously acquire wide spectral information. A MSFA image sensor with R, G, B, and near-infrared(NIR) filters can obtain the mixed spectral information of visible bands and that of the NIR bands. Since the color filter materials used in MSFA sensors were almost transparent in the NIR range, the observed colors of multispectral images were degraded by the additional NIR spectral band information. To overcome this color degradation, a new signal processing approach is needed to separate the spectral information of visible bands from the mixed spectral information. In this paper, a color restoration method for imaging systems based on MSFA sensors is proposed. The proposed method restores the received image by removing NIR band spectral information from the mixed wide spectral information. To remove additional spectral information of the NIR band, spectral estimation and spectral decomposition were performed based on the spectral characteristics of the MSFA sensor. The experimental results show that the proposed method restored color information by removing unwanted NIR contributions to the RGB color channels.