We put forth the proposition that multipupil imaging systems can be brought to zero absolute phase in real time, using information in the existent real-scene images. This proposition inverts the usual logic that says `phase the pupils to improve resolution;' we use the magnitude of higher image spatial frequencies to determine the proper phase relationship for the pupils. Defining the spatial frequency region above the single pupil cutoff but below the multipupil cut off as the phasing band, we demonstrate three real-scene sensing approaches that allow us to maximize the energy in the phasing band, at which point the interpupil piston error is zero. A simple two pupil experiment is used in these proof-of-principle demonstrations.
Bruce A. Horwitz,
John T. Watson,
"Real-scene phasing sensor approach: a modest proposal", Proc. SPIE 1543, Active and Adaptive Optical Components, (13 January 1992); doi: 10.1117/12.51198; https://doi.org/10.1117/12.51198