Reflective all-sky thermal infrared cloud imager
A reflective all-sky imaging system has been built using a long-wave infrared microbolometer camera and a reflective metal sphere. This compact system was developed for measuring spatial and temporal patterns of clouds and their optical depth in support of applications including Earth-space optical communications. The camera is mounted to the side of the reflective sphere to leave the zenith sky unobstructed. The resulting geometric distortion is removed through an angular map derived from a combination of checkerboard-target imaging, geometric ray tracing, and sun-location-based alignment. A tape of high-emissivity material on the side of the reflector acts as a reference that is used to estimate and remove thermal emission from the metal sphere. In conclusion, once a bias that is under continuing study was removed, sky radiance measurements from the all-sky imager in the 8-14 μm wavelength range agreed to within 0.91 W/(m 2 sr) of measurements from a previously calibrated, lens-based infrared cloud imager over its 110° field of view.
- Montana State Univ., Bozeman, MT (United States). Electrical & Computer Engineering Dept.; Univ. of Arizona, Tucson, AZ (United States). College of Optical Sciences
- Montana State Univ., Bozeman, MT (United States). Electrical & Computer Engineering Dept.
- Montana State Univ., Bozeman, MT (United States). Electrical & Computer Engineering Dept.; NWB Sensors, Inc., Bozeman, MT (United States)
- Montana State Univ., Bozeman, MT (United States). Electrical & Computer Engineering Dept.; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- California Inst. of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab.
- Publication Date:
- Grant/Contract Number:
- FA9550-14-1-0140; ARC-1108427; AC05-76RL01830
- Accepted Manuscript
- Journal Name:
- Optics Express
- Additional Journal Information:
- Journal Volume: 26; Journal Issue: 9; Journal ID: ISSN 1094-4087
- Optical Society of America (OSA)
- Research Org:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Org:
- USDOE; National Science Foundation (NSF); US Air Force Office of Scientific Research (AFOSR); Montana Space Grant Consortium (MSGC); National Aeronautics and Space Administration (NASAJ)
- Country of Publication:
- United States
- 47 OTHER INSTRUMENTATION
- OSTI Identifier: