Automated chain line marking and pattern matching in radiographs of Rembrandt's prints

摘要

The sieve-like molds used in early paper manufacturing leave characteristic chain line patterns that can help determine if two pieces of paper were made using the same mold [1]. Such moldmates can help in establishing chronology, suggest paper preferences, and indicate periods of intense activity of an artist, and the study of Rembrandt's prints has occupied a prominent place within this scholarship [2]. There are two basic steps to the automation of the analysis [3], [4]. First, the chain lines must be accurately marked, extracting points and lines from the x-ray images. Second, the markings from many x-rays must be compared to find matches. This paper presents improved algorithms for both of these tasks. Section II follows [6] in replacing the classic Radon transform approach of [5] (which requires that the chain lines be straight) with a local method that outputs marked grids of points. The method segments the images, corrects for tilt, filters, conducts a (local) Radon transform and then concludes with a peak detection. The marked grids from a large collection of x-rays of Rembrandt's prints are then used in Section III as input to the matching algorithm.