Estimation of the sky radiance

For the infrared prefilter model there was a need for testing the sky radiation and defining its fluctuations within the zone of neighborhood area for the current frame and tests of repeatability. It was necessary to do the statistical processing of sky fluctuations in the current frame, because the sky is represented by corresponding layers through which the infrared image prefiltration is done. In this paper the uniformity for low elevation angles has been confirmed. The lower effective temperatures differences exist at large elevation angles.