Optical beam transmittance for a horizontal path of sight through the atmosphere may be measured with transmissometers, which typically are double-ended, with source and a receiver at opposite ends of the path. Determination of the beam transmittance for longer paths is more challenging in some applications, such as monitoring the surround of a ship at sea or an urban environment. Extinction imaging is a new, to the best of our knowledge, method we have developed for determining the beam transmittance and effective path extinction coefficient over extended atmospheric paths in multiple directions with a single-ended system. Our new advances to the classical theory are enabled by use of calibrated imagers operating in visible, near-infrared, or short-wave infrared wave bands. This article presents the theory, hardware, and tests with supporting instrumentation, including transmissometers and point scatter meters. (C) 2019 Optical Society of America
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