Digital restoration of ancient color manuscripts from geometrically misaligned recto-verso pairs

We propose a fast automatic procedure for registration and restoration of images of recto-verso pairs of color manuscripts affected by bleed-through distortion. The registration algorithm assumes a rigid projective deformation of a side with respect to the other. The coefficients of the geometric transformation are computed from a large number of pairs of matching points, automatically detected by exploiting the estimates of local shifts between pairs of small patches. We validate the efficiency of the registration algorithm through the performance of a restoration method based on a model that relates each couple of corresponding pixels in the two images, and thus requiring a very accurate alignment of the two sides. The experiments show that this combined procedure of registration plus restoration can provide an excellent removal of the bleed-through pattern, while leaving unaltered the salient features of the original manuscript.