Detective Scientists: Cossairt & Katsaggelos Discover Ancient Clues in Mummy Portraits

Using non-destructive and non-invasive techniques, their team can extract information about the underlying surface shapes and color of mummy portraits.

Prof. Oliver (Ollie) S. Cossairt & Prof. Aggelos K. Katsaggelos

Prof. Oliver (Ollie) S. Cossairt, Lisa Wissner-Slivka and Benjamin Slivka Junior Professor of Computer Science and Prof. Aggelos K. Katsaggelos, AT&T Professor are members of an interdisciplinary team (lead by Dr. Marc Walton) that have used non-destructive and non-invasive techniques to extract information about the underlying surface shapes and color of mummy portraits. The new details, when coupled together, provide the researchers with very strong evidence as to how many of the 15 mummy portraits and panel paintings were made.

Optics expert Cossairt and signal processing analyst Katssagelos, developed two of the key analytical tools.

Cossairt’s computational cameras captured a series of images of the portraits under different angles of illumination to examine the surface shape of the objects. Using an imaging algorithm called photometric stereo, the researchers were able to recover quantitative measurements of brush and tool marks.

For measurements of color, visible hyperspectral imaging data was collected between the ultraviolet through the near-infrared range. Regions on the paintings were compared to dictionaries of reflectance spectra of pigments used in the Roman period and mined using Katasaggelos’ machine-learning algorithms. Read More

Excerted from an Monday, February 15, 2016 article published by Northwestern News, titled, "Detective Scientists Discover Ancient Clues in Mummy Portraits."