Acquisition of spectral reflectance data using an artificial source of hemispherical illuminationAn integrating hemisphere illumination system has been developed to facilitate the collection of spectral reflectance factor measurements of targets of interest in a laboratory environment. One of the most significant advantages associated with such an illumination source is that repeated measurements can be made over an extended period of time, for a variety of targets, under nearly identical illumination and viewing angle conditions. The illumination system consists of a 76 cm (30 in.) aluminum hemisphere coated internally with barium sulfate paint. Illumination is provided by sixteen 62 watt quartz halogen bulbs with tungsten filaments. A simple metal structure has been developed to hold the hemisphere and all peripheral equipment, such as spectrometers, radiometers, and cameras, in place during data collection. The entire set up can be easily disassembled and packed in airline-approved shipping cases to facilitate transportation to laboratory facilities located near any study area. The illumination system is described briefly, and numerous plots of radiance and spectral reflectance are provided to illustrate the performance and utility of the apparatus.
Document ID
19890040409
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Williams, Darrel L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wood, Frank M., Jr. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Case, David W. (Science Applications Research Lanham, MD, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1988
Subject Category
Instrumentation And Photography
Meeting Information
Meeting: Recent Advances in Sensors, Radiometry, and Data Processing for Remote Sensing