Data Collection and Modeling of In-Flight Intrinsic Contrasts of Aircraft.

摘要

Mathematical modeling to predict the ability of a human observer to visually search and detect aircraft against a sky background requires luminous contrast as an input parameter. This, in turn, depends on average luminance of the aircraft silhouette and its relation to sun angle. The purpose of the reported study was to test the diffuse (Lambertian) reflecting sphere as a model for introducing illumination geometry, principally the solar phase angle, into the prediction of aircraft luminance. The test consisted of a comparison of model prediction with field test data consisting of photographic imagery of low-altitude aircraft. The photographic data were reduced through two-dimensional scanning densitometry to yield mean silhouette luminance. These values were compared to values predicted by a diffuse sphere model with the comparison including a full account of atmospherics. A discussion of the comparison is included. (Author)