Impact of the atmosphere, view and illumination geometry and flight profile on ground target separability

A two-part study was conducted to experimentally examine the effects of small changes in sun-target-sensor geometry and altitude on lens falloff and resulting image data. Part one was a multi-altitude collection using radiometrically-calibrated targets. Part two was a single-altitude collection over a heterogeneous forest canopy. A framework for correcting individual images for changes in illumination profiles due to lens falloff was developed. Results from this study show there are small differences noted in image data due to lens falloff with an increase in altitude. Effects of surface heterogeneity and reflectance anisotropy are demonstrated. The methodology established could be used to validate or calibrate existing atmospheric models and quantitative comparisons of individual images.