A Demosaicking Algorithm with Adaptive Inter-Channel Correlation

Most common cameras use a CCD sensor device measuring a single color per pixel. Demosaicking is the interpolation process by which one can infer a full color image from such a matrix of values, thus interpolating the two missing components per pixel. Most demosaicking methods take advantage of inter-channel correlation locally selecting the best interpolation direction. The obtained results look convincing except when local geometry cannot be inferred from neighboring pixels or channel correlation is low. In these cases, these algorithms create interpolation artifacts such as zipper effect or color aliasing. This paper discusses the implementation details of the algorithm proposed in [J. Duran, A. Buades, “Self-Similarity and Spectral Correlation Adaptive Algorithm for Color Demosaicking”, IEEE Transactions on Image Processing, 23(9), pp. 4031–4040, 2014]. The proposed method involves nonlocal image self-similarity in order to reduce interpolation artifacts when local geometry is ambiguous. It further introduces a clear and intuitive manner of balancing how much channel-correlation must be taken advantage of. Source Code An ANSI C source code implementation of the described algorithms is accessible at the IPOL web page of this article1, together with an on-line demo.