TERRAIN ANALYSIS BY ELECTROMAGNETIC MEANS. REPORT 4. LABORATORY INVESTIGATIONS OF THE INFRARED EMISSIVITY OF SOILS BELOW A WAVELENGTH OF 7.7 MICRONS.
Abstract
This investigation was made to consider the feasibility of (1) remotely determining soil infrared emissivity through use of an infrared scanning system and (2) relating this emissivity to parameters such as soil type, moisture content, and dry density. Such a system, responsive to radiation below a wavelength of approximately 7.7 microns, was used in the laboratory to measure the variation of infrared emissivity of soils with various moisture contents. Initially, infrared images of laboratory-prepared soil samples were recorded so that the tone densities of the images could be correlated with soil parameters. The two imaging devices available were a facsmile recorder and an oscilloscope. The facsimile recorder was used first but was found to be incompatible with the rest of the system, resulting in unsuitable imagery. Therefore the facsimile recorder was abandoned in favor of the oscilloscope as a means of obtaining thes images. Although the images per se formed on the face of the cathode ray tube and recorded on photographic negatives were of good quality, their tone densities could not be correlated with the above-mentioned soil parameters. Finally, a technique was evolved wherein the wave form of the voltage variation, which resulted from a single scan of the sample and its associated reference bodies, was used to make the analysis. The data indicate that the soil emissivity values that can be obtained from a passive infrared sensor through use of the technique derived herein are not sufficiently accurate to predict meaningful trafficability parameter values.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1967
- Accession Number
- AD0815453
Entities
People
- Albert N. Williamson Jr.
- Hans J. Nikodem
- Nicholas J. Lavecchia Jr.