Optical coherence tomography: non-destructive imaging and spectral information of pigments

Optical Coherence Tomography (OCT) is a non-invasive and non-destructive technique which is very interesting for the study of works of art. Based on a Michelson interferometer, our device has been adapted for the recording of information in the visible range. This system allows three-dimensional imaging of painting with a micrometer resolution. 3D imaging of pictorial layers is presented where the pigments embedded in the binder are clearly visible. Furthermore, an adapted signal processing gives access to the spectral information issued from pigments. Tests on pigments in powder are presented and show that their spectral responses are different.