Fig. 7From: Extracting chain lines and laid lines from digital images of medieval paper using spectral total variation decompositionLaid line extraction based on the Radon transform (top) compared to extraction using rectangular filtering in the Fourier domain (bottom). The latter is highly influenced by noise and detects too many lines and at incorrect positions. Reproduced by kind permission of the Syndics of Cambridge University Library, MS Ii.5.41, fol. 10rBack to article page