Color Image Demosaicing Using Iterative Residual Interpolation

A recently developed demosaicing methodology, called residual interpolation (RI), has demonstrated superior performance over the conventional color-component difference interpolation. However, it has been observed that the existing RI-based methods fail to fully exploit the potential of RI strategy on the reconstruction of the most important G channel, as only the R and B channels are restored through the RI strategy. Since any reconstruction error introduced in the G channel will be carried over into the demosaicing process of the other two channels, this makes the restoration of the G channel highly instrumental to the quality of the final demosaiced image. In this paper, a novel iterative RI (IRI) process is developed for reconstructing a highly accurate G channel first; in essence, it can be viewed as an iterative refinement process for the estimation of those missing pixel values on the G channel. The key novelty of the proposed IRI process is that all the three channels will mutually guide each other until a stopping criterion is met. Based on the restored G channel, the mosaiced R and B channels will be, respectively, reconstructed by exploiting the existing RI method without iteration. Extensive simulations conducted on two commonly-used test datasets for demosaicing algorithms have demonstrated that our algorithm has achieved the best performance in most cases, compared with the existing state-of-the-art demosaicing methods on both objective and subjective performance evaluations.