Field spectroscopy for multispectral remote sensing: an analytical approach.

In response to the increasing concern for more introspective remote sensing programs from space platforms, a number of satellite programs have been initiated that have since provided a wealth of information for earth resource programs. Application of these data has generated widespread interest in ground truth studies with photographic aerial remote sensing techniques playing a major role. Such investigations have motivated increasing interest in the radiometric concepts involved, in particular, the reflected radiance of objects appearing in a ground scene. The intention of this paper is to present application problems associated with some of the existing reflectance data and point out the geometrical considerations necessary for field spectroscopy. Definitions of reflectance eminating from the quadravariate reflectance distribution function [E. W. Ginsberg, T. Limperis, F. E. Nicodemus, and J. C. Richmond, "Infrared Radiometry Instrument Calibrations and Precision Measurements," University of Mic higan Engineering Summer Conference (June 1969)] are described, and attention is drawn to the compromise between measurement complexity and application limitations. In this context a field spectroradiometric system is described, and results from an application of the system to remote sensing of rock types are presented.