Acquiring a priori knowledge from ground and spaceborne BRDF measurements

Previous work has successfully demonstrated the application of a priori knowledge to bidirectional reflectance distribution function (BRDF) model inversion. The a priori knowledge used in the tests is the general knowledge which can be applied to all land cover types. One of the advantages of general knowledge is that it can be applied independently and doesn´t need more information. However, the inversion accuracy may be low, compared to results using correct specific knowledge. This paper mainly focuses on the accumulation of a priori knowledge for the linear BRDF model in both general and specific realms. The authors first provide some specific knowledge based on ground and spaceborne BRDF measurements for BRDF model parameters