Factors related to low-slant angle affecting airborne video interpretability
Darrell L. Young, Tariq Bakir, Robert Butto, Fred Petitti · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2010
The following material is given to address the effect of low slant angle on video interpretability: 1) an equation for the minimum slant angle as a function of field-of-view to prevent no more than a &sqrt2; change in GSD across the scene; 2) evidence for reduced situational awareness due to errors in perceived depth at low slant angle converting to position errors; 3) an equation for optimum slant angle and target orientation with respect to maximizing exposed target area; 4) the impact of the increased probability of occlusion as a function of slant angle; 5) a derivation for the loss of resolution due to atmospheric turbulence and scattering. In addition, modifications to Video-NIIRS for low slant angle are suggested. The recommended modifications for low-slant angle Video-NIIRS are: 1) to rate at or near the center of the scene; and 2) include target orientations in the Video-NIIRS criteria.