Measurement of the BRDF over the visible spectral range at a submillimeter scale

For some materials such as fabric, wood or leathers, the distance of observation greatly influences its appearance. Knowing the optical properties at a micrometric scale of these materials is important to understand and reproduce the appearance of the full object. However, there is no existing goniospectrophotometer that can perform BRDF measurement at a submillimetric scale. In fact, decreasing the spatial resolution of BRDF measurements brings forward specific metrological issues that have so far not been addressed. During the project, we will build a set-up allowing to investigate BRDF at a micrometric scale and to establish a multi-scale traceability between small measurement areas and classic measurement areas.