MISR abstract
Chrien, N.C.L, E.C. Hagerott, M.L. White, C.J. Bruegge, and E.R. Freniere (1994). Contrasting target, stray-light, and other performance metrics for MISR. IGARSS '94. International Geoscience and Remote Sensing Symposium. Surface and Atmospheric Remote Sensing: Technologies, Data Analysis and Interpretation (Cat. No.94CH3378-7). 8-12 Aug, Pasadena, California, USA. 4, 2001 - 2003.
The Multi-angle Imaging Spectrometer (MISR) is an Earth-observing sensor to be flown as part of the Earth Observing System (EOS) in 1998. The radiometric and spectral calibration of the nine cameras which compose this instrument will be done using targets which are uniform in space and in angle, unpolarized, and lacking in absorption lines. A calibration uncertainty will also be determined for this configuration. This allows one to estimate the accuracy of measured radiances, assuming the scene is likewise featureless with respect to these parameters. In addition to these calibrations, the MISR engineering team will be responsible for verification of certain performance specifications which assure data products can be produced for a range of target types. MISR is specified to be insensitive to the state of polarization of the incident field to within ±1%; it must recover from saturation within eight line repeat times; blooming in the event of saturation shall be limited to the eight adjacent pixels; stray-light shall be rejected to a degree sufficient to maintain the radiometric-requirements of the within-field target; and radiometry will be preserved while observing two specific contrasting scenes. The first scene is 5% in reflectance for one half-plane, and 100% in reflectance for the other half-plane. Radiance retrieval over the dark scene 24 pixels distance from the bright/dark boundary shall differ by no more than 2% from the retrieval over a uniform 5% dark plane (lack of bright half-plane). This specification guarantees a specified level of accuracy for a large dark expanse, such as the ocean surface. The second specification defines a scene which is 50% in reflectance except for the center 24×24 pixels, which are 5% in reflectance. The radiance retrieved anywhere within the dark region shall differ by no more than 2% than for the case where the scene is completely 5% dark. This scene type could be used, for example, in the aerosol retrieval algorithm where a lake surrounded by brighter land is investigated. Due to the need to estimate performance prior to hardware build, and due to the difficulties in constructing test targets for an unlimited number of scene types MISR will combine test and analyses to verify these specifications. Currently a stray-light analysis program is assisting in the camera design process, for the purpose of minimizing ghost imagery and spectral cross-talk. The point source transmittance function from the stray-light code is used to predict the blurring of energy in the presence of a contrasting target. Results of these analyses, and test plans are reviewed