Spectral-domain optical coherence tomography for the non-invasive investigation of the pigment layers of Tang Dynasty tomb murals exhibited in museums

Abstract

Optical coherence tomography (OCT) is a non-invasive subsurface three-dimensional imaging technique based on the Michelson interferometer. Due to the nature of non-invasive detection and high-speed acquisition, OCT is efficient for imaging intact objects to generate a complete overview of their microstructure. This paper presents the investigation of the pigment layer and ground layer of three Tang Dynasty tomb murals exhibited in museums with Spectral-domain optical coherence tomography (SD-OCT). The investigation results demonstrated that SD-OCT system can obtain clear images of the subsurface microstructure and preservation status of ancient murals and can precisely locate and measure the location of the mural defect, by means of en-face image, the system can distinguish the draft line covered by pigment layer. The SD-OCT is an attractive alternative for cultural heritage research and high-resolution OCT images can provide valuable information for Chinese cultural heritage research, identification, and conservation.