Netherlands Institute for Conservation, Art and Science

Large volume imaging of cultural heritage with optical coherence tomography

Optical coherence tomography (OCT) is a nondestructive imaging technique capable of imaging 3D images of thin layered structures up to a few millimeters deep. Applications within the field of material science research and cultural heritage studies are structural and stratigraphy analysis of layered objects and varnish layers.

Our OCT imaging system has an axial (depth) resolution of 3.0 μm and a lateral resolution of 4 μm in air. The system is capable of imaging high resolution cross-sectional images of varnish layers. Sample properties such as stratigraphy, layer thickness, attenuation coefficient and refractive index are accessible from the OCT signal.

Current OCT systems work by scanning the beam over the sample using galvanometric mirrors yielding scanning areas typically 10x10 mm^2, much smaller than many works of art. This limits the practical usability of the technique.

In this work we present a setup, consisting of scanning stages and the OCT device, that enables us to scan up to 20 x 20 x 0.2 cm volumes of cultural heritage. Specifically designed software regulates synchronized scanning, dynamic focus control, image registration, image segmentation and user friendly image rendering. The resulting image enables conservators to assess the condition (layers) of a large volume of an object and judge the results of resulting (restaurative) interventions.

Principal researcher

Tom Callewaert (Delft University of Technology)

Type of project

PhD

Participating researchers

  • Joris Dik (supervisor)
  • Jeroen Kalkman (supervisor)
  • Petria Noble
  • Katrien Keune
  • Annelies van Loon
  • Paul van Duin
  • Jan Dorscheid
  • Idelette van Leeuwen
  • Martin Jurgens
  • Rosina Herrera Garrido
  • Rob Erdmann

Institutions involved

  • Delft University of Technology
  • Rijksmuseum
  • Mauritshuis

Expected completion date

December 2018.

Funded by NWO.

Published by  NICAS

14 November 2017