An active optical remote sensing system for vegetation index determination

An airborne hyperspectral remote sensing system, initially for use to verify theories for rapid, accurate determination of vegetation indices, is described. The system, called AVIS (Airborne Vegetation Index Sensor), is mounted on a helicopter and employees a Xenon flash lamp to illuminate the Earth's surface. The backscattered radiation is measured with better than 10 nm resolution in the visible and near-IR over a shiftable 400 nm bandpass. Background subtraction is used for daytime flights. By its nature, AVIS measures the hot spot, resulting in no shadowing. It is a versatile system, minimizing atmospheric effects and eliminating view angle variables and other ambiguities and assumptions associated with general algorithm development and verification which arise when using the sun as a test source.