Context-Based Defading of Archive Photographs

Abstract

We present an algorithm for the enhancement of contrast in digitized archive photographic prints. It aims at producing an adaptive enhancement based on the local context of each pixel and is able to operate without direct user's intervention. A relation between the variation of contrast at different resolutions and the local Lipschitz regularity of the image is exploited. In this way, each pixel is defaded according to its nature: noise, edge, or smooth region. This strategy provides for an algorithm that drastically reduces typical, annoying artifacts like halo effects and noise amplification.