Paper
5 October 2006 Measurements of the effect of falling snow on imaging with infrared cameras
Author Affiliations +
Proceedings Volume 6395, Electro-Optical and Infrared Systems: Technology and Applications III; 639507 (2006) https://doi.org/10.1117/12.689699
Event: Optics/Photonics in Security and Defence, 2006, Stockholm, Sweden
Abstract
We present results from imaging experiments performed in Norway during the 2005/06 winter season. Pairs of infrared sources with different temperatures are placed at different distances, ranging from 50 to 1200 m, from two focal plane array infrared cameras. One of the cameras is sensitive in the 3-5 μm wavelength range and the other in the 8-10 μm wavelength range. During the winter months digital sequences of the IR-sources were recorded, under different meteorological conditions. These conditions ranged from perfectly clear, cloudless weather to heavy snowfall. Analysis consists of comparing the perceived contrast, as measured with the cameras, with the "real" contrast as defined by the temperatures of the IR-sources. It is assumed that the transmission coefficient is the product of the atmospheric transmission (without snow) and a transmission factor associated with the falling snow. FASCODE simulations, using the pertinent temperature and humidity data that were measured during the recordings, are performed to characterize the atmospheric transmission coefficient (without snow). A comparison of the experimental results and the simulation results allows one then to estimate the effect of the falling snow on the extinction coefficient or visibility range. We observed a strong negative correlation between visibility and precipitation rate and better visibility in the MWIR range than in the LWIR range.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Arthur D. van Rheenen, Lars T. Heen, Eirik B. Madsen, Erik Brendhagen, and Kjell Wikan "Measurements of the effect of falling snow on imaging with infrared cameras", Proc. SPIE 6395, Electro-Optical and Infrared Systems: Technology and Applications III, 639507 (5 October 2006); https://doi.org/10.1117/12.689699
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KEYWORDS
Visibility

Cameras

Long wavelength infrared

Mid-IR

Temperature metrology

Sensors

Content addressable memory

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