Perceptual hashing for hardcopy document authentication using morphological segmentation.
Diego Massola Shimizu, Hae Yong Kim · Biblioteca Digital da Memória Científica do INPE (National Institute for Space Research) · 2007
Semi-fragile authentication of hardcopy documents is a technique designed to detect any visually signi cant alteration in a document, while ignoring incidental alterations, like distortions resulting from