Recovery of Images from the AMOS ELSI Data for STS-33

During the STS-33 space-shuttle mission in November 1989, ground-based observations of the shuttle were made from the Air Force Maui Optical Station AMOS in Hawaii during five orbits that passed near the observatory. The objective of these measurements was the study of interactions between contaminant gases of the shuttle and the residual atmosphere at orbit altitude. The Enhanced Longwave Spectral Imager ELSI was one of the instruments used. The ELSI employs two infrared-sensitive array detectors at a telescope focal plane. The recorded digital data from the MWIR detector used in this instance were found to be unusable under ordinary processing methods because five of the twelve bits in each pixel value were found not to be operating. This report describes the further examination of these data, the discovery of other faults in the instrument, and the subsequent development of software routines and a correction algorithm that succeeded in completely recovering the true images contained in the data. Criteria for the success of this method are examined in the course of describing the design of the algorithm. The method has been transfered to the organization that will process similarly flawed classified data from this instrument. Keywords Array detectors, Image processing, Correction algorithms, Data recovery, Infrared imagers, Telescope focal plane.