Previously we presented a TV-based super-resolution sharpening-demosaicing method. Our previous method makes it
possible to restore frequency components higher than the Nyquist frequency, and to interpolate color signals effectively
while preserving their sharp color edges, without producing ringing artifacts along the edges. However, since our
previous method applies the TV regularization separately to each primary color channel, as side effects it sometimes
produces false color artifacts and/or zipper artifacts along sharp color edges. To remedy the drawback, in addition to the
TV regularization of each primary color signal, we introduce the TV regularization of color difference signals such as
G-R, and that of color sum signals such as G+R, into the TV-based super-resolution sharpening-demosaicing method.
Near sharp color edges, correct interpolation provides the smallest TV norms of color difference signals or the smallest
TV norms of color sum signals. Unlike our previous method, our new method jointly interpolates the three primary
color channels. We compare demosaicing performance of our new method with the state-of-the-art demosaicing
methods. In the evaluations, we consider a noise-free case and a noisy case. For both cases our new method achieves the
best performance, and for the noisy case our new method considerably outperforms the state-of-the-art methods.