Imaging Through Atmospheric Obscurants

SWIR vs VIS in Hazy Environment

Utah's Salt Lake Valley occasionally experiences an atmospheric phenomenon which traps air pollution for days or weeks at a time. During these atmospheric inversion events, ground-level visibility is severely reduced. This video compares visible imagery and shortwave infrared (SWIR) imagery during a period of very low ground-level visibility on December 7, 2017 at approximately 3:30 pm MST.

The SWIR imagery was captured at 60FPS with the Sensors Unlimited 1280JSX High Definition Mini SWIR area camera and a 200mm SWIR optimized f/1.6 lens. The visible imagery was captured with a Nikon D5100 DSLR camera in video mode and a 55-200mm f/4.5-5.6 lens. Both sets of imagery are cropped but are otherwise unchanged. The SWIR camera outperforms the visible camera primarily because SWIR photons are able to penetrate through atmospheric haze and smog while visible wavelength photons are scattered in air that is heavy with particulate matter.