Goniometer Facility

A major research item for the coming years is assessing the anisotropic reflectance  behaviour of vegetation and soils, as described by the bidirectional reflectance distribution function (BRDF). Information on the BRDF of targets is relevant for normalizing images taken under different illumination and/or viewing conditions, but on the other hand multi-angular observations also provide additional information that can be used to improve the accuracy of retrieved products. To support on-going research in this field, we realized a laboratory measurement facility to assess the anisotropic reflectance behaviour of soils, leaves and small canopies under controlled illumination conditions.

The System

A commercially available robotic arm enables the acquisition of a large number of measurements over the full hemisphere within a short time span making it much faster than other goniometers. In addition, the presented set-up enables assessment of anisotropic reflectance and emittance behaviour of soils, leaves and small canopies. Mounting a spectrometer enables acquisition of either hemispherical measurements or measurements in the horizontal plane. Mounting a thermal camera allows directional observations of the thermal emittance. A detailed description of the system can be found in Roosjen et al. (2012).


Research within the Laboratory of Geo-Information Science and Remote Sensing is focused on: