Infrared Aerial Surveys in Environmental Engineering

To obtain full advantage of the techniques involved in remote IR sensing, the basic principles related to the nature of IR radiation and the problems associated with its atmospheric attenuation are reviewed and illustrated. Some of the basic differences between IR photography and imagery are analyzed. Illustrations are provided which illuminate the techniques that have been used to locate thermal water pollution by IR sensing. Further illustrations indicate the facility of IR imagery to display stream valleys and subsurface drainage patterns. The location of buried conduits and utility systems are illustrated to highlight another valuable use of IR sensing in revealing near surface features. The potential application of aerial IR surveys for detecting and tracing the movements of air pollution is examined. Some spectroscopic absorption and emission techniques for identifying specific gases are reviewed. Several arrangements for positioning monochromatic and broad band IR sources relative to elevated or airborne detectors are suggested for air pollution studies. The advantage in using IR photography from spacecraft for delineating smoke streams is shown.