Radiometric performance of 640x480 and 320x244 PtSi IR cameras

Camera designs and radiometric performance evaluation results are presented for two PtSi IR imagers fabricated by the David Sarnoff Research Center. Measurements on the 640 X 480 IR-MOS imaging radiometer with 25 to 150 degree(s)C background temperatures indicated response non-linearity less than +/- 0.3% over 80% of the full signal range. By operation with variable integration time from 240 microsecond(s) ec to 33 msec a scanned image with a NE(Delta) T of less than 0.1 degree(s)C can be maintained over the full temperature range. The 320 X 122 IR-CCD imaging radiometer was designed for operation with integration times ranging from 0.12 to 133 msec to provide for 12 snapshot image settings. The signals from various integration times were effectively matched and scaled to increase the effective maximum measured signal from 1 X 106 to 50 X 106 electrons/pixel. Correction procedures were developed for achieving radiometric accuracy for achieving radiometric accuracy for operation of the imagers over multiple integration times and taking into account the effects of non- linear response of dark current and charge trapping in the readout BCCD registers. The camera stability was shown to be limited by the stability of the calibration source over a three- hour period.