Abstract
In this communication, we illustrate an enlarging and enhancing procedure adequate to provide the restorer with sufficiently detailed digital versions of frescos in the excavations of Pompeii and Hercolaneum, starting from the photographic prints taken and archived in the early thirties for documentation purposes. Image filtering is preliminarily done to improve the quality of the input data by removing acquisition and digitization noise. Image enlargement is then accomplished by using bilinear approximation. Image enhancement can finally be accomplished. Since our purpose is to enhance only edges, we must distinguish in the enlarged image edge regions from non-edge regions. We achieve this goal by applying edge detection and by thresholding the computed edge image. The obtained binary image is used as a reference to apply edge sharpening onto the enlarged image, and so obtain the enhanced image as desired. Though designed for a specific application, our method is indeed rather general.