Proceedings Article | 28 December 1999
George McCabe, Dennis Reuter, Donald Jennings, Peter Shu, Si Chee Tsay, Patrick Coronado, Peter Mantica, Stephen Cain, Mark Abrams, Arthur Boright, John Ross, Rumen Dimitrov, Stuart Picketh
Proc. SPIE. 3870, Sensors, Systems, and Next-Generation Satellites III
KEYWORDS: Hyperspectral imaging, Optical filters, Fabry–Perot interferometers, Imaging systems, Sensors, Calibration, Spectroscopy, Image filtering, Space operations, Imaging arrays
In this presentation we describe flight results for an airborne IR hyperspectral imager used as a test bed for LEISA, a compact spaceborne wedged filter spectrometer. The moderate spectral resolution Linear Etalon Imaging Spectral Array (LEISA) is a low-mass, low-power, low-cost infrared spectral imager for spacecraft applications. LEISA uses a state-of-the- art wedged infrared filter (a linear variable etalon, LVE) in conjunction with a detector array to obtain hyperspectral image cubes. The LEISA concept has been described previously in Reuter et al., 1997, SPIE Vol. 2957, pp 154 - 161, 'EUROPTO Conference on: Advanced and Next-Generation Satellites II.,' 23 - 26 September, 1996, Taormina, Italy. A LEISA type instrument, the Atmospheric Corrector (LAC), will fly on NASA's EO-1 spacecraft to be launched in Dec. 1999. The airborne version of LEISA covers the spectral region from 1.0 to 2.5 microns at a constant resolving power ((lambda) /(Delta) (lambda) ) of approximately 250 (i.e. 4 nm 1.0 microns and 10 nm 2.5 microns). The single pixel spatial resolution is 2 milliradians. This corresponds to 2 meters 1 km altitude and 20 meters 10 km. The instrument has been operated throughout this altitude range. The instrument has a swath width of approximately 29 degrees. A 256 X 256 element NICMOS (Near Infrared Camera Multi-Object Spectrometer) HgCdTe detector array is used as the focal plane. The focal plane is enclosed in a small cryogenic dewar at liquid Nitrogen temperature. Results will be presented for three series of airplane flights: Lubbock Texas (USA) June - September 1997, Lubbock Texas (USA) July - September 1998, Bethlehem Orange Free State (South Africa) March 1999. Issues to be discussed include pre-, and post-flight calibration, image registration and spectral image reconstruction. The relationship of these measurements to future spaceborne hyperspectral imagers will also be discussed.
