Raytheon Company

Michael Weinstein

Martin Austin Wand

John F Brady

David D Ratcliff

Kenneth Rachels

A method for measuring the temperature of a scene using a detector having at least one reference pixel, with an integratable sampling circuit associated with each pixel. Initially, an ambient reference temperature is observed with the reference pixel(s) to provide a parameter, generally voltage, indicative of that temperature to provide a constant voltage output indicating that temperature by varying the sampling circuit integration time. Each non-reference pixel is exposed to different scene and ambient temperatures and the integration time for each set of data for each pixel is recorded. For each pixel, an equation is provided relating integration time to pixel voltage when the ambient temperature and the scene temperature are the same to correct for offsets and an equation is provided relating integration time and offset corrected pixel value to the difference between the ambient temperature and the scene temperature when the ambient temperature and scene temperature differ for correction of responsivity. An equation is provided relating integration time to ambient temperature for calculating ambient temperature. The voltage level for each of the pixels and the integration is determined, the offset correction for each pixel is calculated based upon the integration time and the offset correction is applied to the pixel value for each pixel. The responsivity corrected value is calculated for each pixel based upon the integration time and the offset corrected pixel value. The ambient temperature is calculated based upon the integration time and the temperature difference between the ambient temperature and the scene temperature for each pixel which is calculated based upon the responsivity corrected pixel value using a scale factor determined during calibration. The ambient temperature and the difference between the ambient and the scene temperatures are added to obtain the actual scene temperature.

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Plano, TX, United States of America

Michael Weinstein