Analytic Techniques for Estimating Visible Image Transmission Properties of the Atmosphere.
Interim scientific rept.,
SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA VISIBILITY LAB
Pagination or Media Count:
The development of field oriented techniques for determining the atmospheric effects on visible image transmission are described in this report. Simplified analytic methods are presented for calculating the background sky, cloud and terrain radiance distribution, and in turn the spectral contrast transmittance, of inclined paths of sight in the atmosphere. The directional path radiance is determined as the sum of the singly scattered sunlight component and a multiply scattered diffuse component that is calculated through application of the delta-Eddington approximation. Performance tests of the model radiance calculations were carried out through comparisons with results from more comprehensive radiative transfer models and by direct comparisons with high-resolution scanning radiometer measurements gathered by instrumented aircraft in a broad range of environmental conditions. Techniques for the representation of the optical parameters required as model input data are presented and discussed, including the specification of cloud optical depth as a function of cloud type. An added feature of the contrast transmittance modeling system deals with the combined influences of atmospheric and target factors in order to calculate visual detection range for objects located at the surface and viewed from alot. Analytic representations of vision experiment data are added along with target information to explore the relative sensitivity of detection range to selected changes in target and atmospheric parameters. Results are presented for several examples assuming simplified targets and backgrounds.
- Optical Detection and Detectors