Photographic Simulation Techniques for Visualizing the Effect of Uniform Haze on a Scenic Resource

Abstract

The paper describes image processing techniques which can be used to photographically represent modeled impacts of uniform haze on a visual resource. A base slide of some vista of interest and representing clean air conditions is digitized and placed on magnetic tape. Each scenic element (pixel) is then modified to correspond to a pre-specified air pollution condition.After modification, the digitized information is used to create a photo of how the visual resource would appear under the specified condition. In order to effectively image the impact of air pollution on a landscape feature it is necessary to know the inherent radiance field of each scenic element and the distance between the observer and each scenic element. If landscape features are located at discrete observer-target distances it is possible to obtain these distances from topographic maps. However, if distance to landscape features vary continuously as the line of sight approaches the horizon it is necessary to employ two slides, one representing clean air conditions and the other a dirtier condition, to extract distances to each scenic element. In either case the inherent radiance field is extracted from the clean air slide. Both approaches have been successfully employed and modified scenes using themore » first technique are included in this paper. (JMT)« less