Optical Coherence Tomography (OCT)

OCT gives fast, non-invasive, non-contact, imaging of stratigraphy, 3D surface and subsurface microstructure. ISAAC is equipped with a range of OCTs, mostly in-house developed systems, that range in central wavelengths from the visible to the near infrared offering a range of specifications from ultra-high resolution (~1 microns) to deep penetration into highly scattering materials. Detailed specification is given in the table below.

Mounting of the probe head is flexible and various adaptations are possible. The speed of acquisition ranges from a few seconds to a few minutes for an image cube of a 1cm x 1cm area. 

UHR-OCT examining an easel painting of National Gallery's collection

Imaging and Sensing for Archaeology, Art History and Conservation (ISAAC)'s OCT Specifications

Applications:

 

  • high resolution and high contrast imaging of underdrawings

  • detection of delamination of internal layers, e.g. enamel

  • monitoring of varnish removal

  • monitoring of glass deterioration

  • non-contact examination of subsurface microstructure of intact objects

  • measuring the hydraulic conductivity of porous materials such as rock art panels

  • study of the manufacturing techniques of ancient artefacts etc.