ACCURATE CALCULATION OF NARCISSUS SIGNATURES BY USING FINITE RAY-TRACING

In scanning IR systems with cooled quantum detectors, the Narcissus si gnature usually has a limiting effect on the perceived image quality, and so ii, is important that it be assessed accurately before manufact ure. We describe a new finite ray-tracing method in which each ray rep resents an equal amount of flux falling on the detector. Such methods require many rays; therefore a full error treatment is given that allo ws designers to estimate the necessary number of rays to obtain the re quired accuracy and also to calculate the standard deviation of the er ror in the final computed result. (C) 1997 Optical Society of America.