Analysis of Techniques for Imaging through the Atmosphere
Interim rept. no. 4 Apr-Oct 1978
OPTICAL SCIENCES CO PLACENTIA CA
Pagination or Media Count:
A detailed analysis of turbulence effects in speckle interferometry, i.e., the Labeyrie technique, and in speckle imagery, the Knox-Thompson algorithm, is presented. Particular concern is devoted to the problem of isoplanatism, as originally we had thought that the Knox-Thompson algorithm might have a very large isoplanatic field-of-view. Our analytic results show that the isoplanatic patch size is approximately the same for Knox-Thompson and Labeyrie methods, and nearly the same as for adaptive optics. It is noted that, unlike the adaptive optics systems for which the ability to record high spatial frequency details is lost due to anisoplanatism, for the speckle methods anisoplanatism does not suppress the high spatial frequency details of the image - it merely jumbles them so that no real information is developed. From these results, it appears that a direct application of speckle techniques will not provide a significant relief from the anisoplanatism problems of adaptive optics. As part of the analysis of the Knox-Thompson method, we develop the conditions for the allowable spatial frequency separation something done previously only by simulation. We find that the allowable spatial frequency separation should be less than 0.427 r sub 0lambda, and preferably should be less than 0.2 r sub 0lambda.