Virtual Restoration: detection and removal of craquelure in digitized image of old paintings

Digital treatment of images has been widely used in many different fields, including astrophysical, medical, geographical and military research. In the last years, digital elaboration of the images has also been used in the field of the Cultural Heritage conservation. Many paintings, especially old ones, suffer from breaks in substrate, paint, or varnish. These patterns are usually called cracks or craquelure and can be caused by aging, drying, and mechanical factors. The appearance of cracks on paintings deteriorates the perceived image quality. However, one can use digital image processing techniques to detect and eliminate the cracks on digitized paintings. Such a "virtual" restoration can provide clues to art historians, museum curators and the general public on how the painting would look like in its initial state, i.e., without the cracks. An integrated methodology for the detection and removal of cracks on digitized paintings is presented in this paper.