Open Access

Nicolas Klenert, Daniel Baum

• This chapter describes the process of digitally unfolding rolled and folded written documents of different materials such as parchment, papyrus, paper, silver, or lead. The folded state of the documents often conceals the information contained in them from the observer, making it difficult to access. Digital unfolding is necessary to prevent damage to the precious historical artifacts, which might occur if one tried to unfold the documents physically to access hidden information. The first step in this digital process is the acquisition of three-dimensional (3D) image data from the document itself, followed by the segmentation of the writing material in the 3D image. Afterward, the segmented material is digitally flattened to obtain an unobscured view of the script. Finally, visualization of the flattened document allows one to make the writing visible. Each of these steps presents distinct difficulties. This chapter outlines the general workflow, together with some key strategies available to overcome these obstacles. Finally, it discusses some remaining core issues and challenges.