Segmentation of Ink and Parchment in Dead Sea Scroll Fragments

TL;DR

Experimental results demonstrate that this Multispectral Thresholding and Energy Minimization (MTEM) method achieves significant improvements over traditional binarization approaches like Otsu and Sauvola in parchment segmentation and is successful at delineating ink borders, in distinction from holes and background regions.

Abstract

The discovery of the Dead Sea Scrolls over 60 years ago is widely regarded as one of the greatest archaeological breakthroughs in modern history. Recent study of the scrolls presents ongoing computational challenges, including determining the provenance of fragments, clustering fragments based on their degree of similarity, and pairing fragments that originate from the same manuscript -- all tasks that require focusing on individual letter and fragment shapes. This paper presents a computational method for segmenting ink and parchment regions in multispectral images of Dead Sea Scroll fragments. Using the newly developed Qumran Segmentation Dataset (QSD) consisting of 20 fragments, we apply multispectral thresholding to isolate ink and parchment regions based on their unique spectral signatures. To refine segmentation accuracy, we introduce an energy minimization technique that leverages ink contours, which are more distinguishable from the background and less noisy than inner ink regions. Experimental results demonstrate that this Multispectral Thresholding and Energy Minimization (MTEM) method achieves significant improvements over traditional binarization approaches like Otsu and Sauvola in parchment segmentation and is successful at delineating ink borders, in distinction from holes and background regions.

Figures (21)

• Figure 1: Ink and parchment segmentation using MTEM
• Figure 2: Multispectral imaging of a DSS fragment at different wavelengths. The images represent bands 1 to 12 from left to right, followed by the color image on the far right. The first seven images are in the visible light spectrum, and the remaining five are in near-infrared.
• Figure 3: An example IAA full-color image showing the color bar, ruler bar, plate-number bar, and the rice paper used to stabilize the fragment.
• Figure 4: The QSD dataset includes full-color, first-band, last-band, and normalized last-band images of each fragment, cropped to exclude the color bar, ruler bar, and plate-number bar. The first-band and last-band images appear dark due to the narrow range of pixel values in the 16-bit format. The full-color image and the normalized last-band image are useful for qualitative evaluation.
• Figure 5: The spectral behavior of ink, parchment, background, hole, and rice materials within a DSS fragment across the 12 spectral bands. This analysis is useful for understanding the most discriminative bands for segmentation of ink and parchment regions