Topographic correction in forested terrain usingsun-canopy-sensor geometry and canopy reflectance models

摘要

Topographic correction based on Sun-Canopy-Sensor (SCS) geometry is more appropriate than sun-terrain basedrncorrections in satellite imagery of forested areas since SCS geometry preserves the geotropic nature of treesrnregardless of terrain, view and illumination angles. However, in some terrain orientations, SCS experiences an overcorrectionrnproblem similar to other simple photometric functions. To address this problem, we present a new SCS+Crncorrection that accounts for this overcorrection based on the C-correction. A rigorous and flexible method forrnindependent validation based on canopy geometric optical reflectance models is also introduced as an improvementrnover previous validation approaches, and forms a secondary contribution of this work. Results for a full range ofrnslopes, aspects and crown closures showed SCS+C provided improved corrections compared to the SCS and fourrnother photometric approaches (cosine, C, Minnaert, statistical-empirical) for a Rocky Mountain forest setting inrnwestern Canada.