Binary Based Fresco Restoration∗

In the following we want to apply digital restoration (inpainting) methods to these frescoes. Thereby the main challenge is to capture the structures in the preserved parts of the fresco and transport them into the damaged parts continuously. Due to their great age and almost 600 years of living by owners and tenants in the apartment, saturation, hue and contrast quality of the colors in the frescoes suffered. Digital grayvalue, i.e., color interpolation, in the damaged parts of the fresco therefore demands sophisticated algorithms taking these lacks into account. In our previous Bridges paper [1] we presented two inpainting methods based on partial differential equations (PDEs) and their application to the reconstruction of the Neidhart frescoes. Because of the lack of space in this paper we refer to Burger et al. [2] for a motivation of the PDE approach and relevant references. The first method in [1] constitutes in a modified Cahn-Hilliard equation for the restoration of the binary structures of the frescoes [2, 3, 4], see Figure 1 for a specific example. The second method is a generalization of this binary inpainting approach for grayvalue images and is called TV-H−1 inpainting [2]. The grayvalue approach produced fairly good results for the inpainting of homogeneous areas in the frescoes, but not very satisfying results for the continuation of edges into the holes [1].