A method has been developed, whereby the optimum focus of an IR telescope may be determined utilizing self imaging. A set of gold-bars, located adjacent to an array of detectors within a cooled focal plane, are reimaged and scanned across the detector array. The respective spatial and temporal frequencies of the gold bars and external scan mirror are selected to maximize the response of the sensor electronics. The resulting response to this cooled periodic stimulus is Fourier transformed and stored in memory for each location of the focal plane. The optimum focus is determined to be the position where maximum power at the stimulating frequency was obtained.

Date Published: 1 October 1990
PDF: 12 pages
Proc. SPIE 1309, Infrared Imaging Systems: Design, Analysis, Modeling, and Testing, (1 October 1990); doi: 10.1117/12.21777

Published in SPIE Proceedings Vol. 1309:
Infrared Imaging Systems: Design, Analysis, Modeling, and Testing