Alessandro Barduccia, Donatella Guzzi, Paolo Marcoionni, Ivan Pippi (2004). Methodology for at-surface BRDF retrieval
from CHRIS-PROBA observations
of the San Rossore (Italy) forestry. Proceedings of the SPIE - The International Society for Optical Engineering: Imaging Spectroscopy X. 5546, pp213 - 222.
Bi-Directional Reflectance Distribution Function (BRDF) of natural targets is a relevant topic to many remote sensing
applications. Recent satellite sensors such as the Multi-angle Imaging SpectroRadiometer (MISR) and the Compact High
Resolution Imaging Spectrometer (CHRIS) supply experimental data to improve the current understanding of directional
properties of reflection from natural surfaces. As a technology demonstrator to evaluate the performance of a compact
and versatile system, CHRIS has been mounted on board of the European Space Agency (ESA) PRoject for On Board
Autonomy 1 (PROBA-1), a small platform provided with advanced pointing capability, which allows the spectrometer to
observe the same target at different viewing angles. In this paper anisotropy factors are retrieved from multiangle CHRIS
images acquired over San Rossore (Italy) forestry test site during the last year. The spectral behaviour of retrieved
factors for different illumination and viewing angles is addressed and analysed. Particular attention is paid to data quality
and geometric and atmospheric effects correction. Finally, the deviation of the retrieved factors from the standard
assumption of a Lambertian target is analysed.