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Optical Engineering

Optimization of the GOES-I Imager's radiometric accuracy: drift and 1/f noise suppression
Author(s): James C. Bremer; Gustave J. Comeyne
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Paper Abstract

The raw output of many scanning radiometers is a small, rapidly varying signal superimposed on a large background that varies more slowly, due to thermal drifts and 1/f noise. To isolate the signal, it is necessary to perform a differential measurement: measure a known reference and subtract it from each of the raw outputs, cancelling the common-mode background. Calibration is also a differential measurement: the difference between two outputs is divided by the difference between the two known references that produced them to determine the gain. The GOES-I Imager views space as its background subtraction reference and a full-aperture blackbody as its second reference for calibration. The background suppression efficiency of a differential measurement algorithm depends on its timing. The Imager measures space references before and after each scan line and performs interpolated background subtraction: a unique, linearly weighted average of the two references is subtracted from each scene sample in that line, cancelling both constant bias and linear drift. Our model quantifies the Gaussian noise and 1/f noise terms in the noise equivalent bandwidth, which is minimized to optimize the algorithm. We have obtained excellent agreement between our analytical predictions and Monte Carlo computer simulations.

Paper Details

Date Published: 1 October 1994
PDF: 10 pages
Opt. Eng. 33(10) doi: 10.1117/12.179397
Published in: Optical Engineering Volume 33, Issue 10
Show Author Affiliations
James C. Bremer, Swales and Associates, Inc. (United States)
Gustave J. Comeyne, Swales and Associates, Inc. (United States)

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