Patent
Wavefront error estimation derived from observation of arbitrary unknown extended scenes
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TLDR
In this paper, a point source wavefront slope sensor is used in scene scanning mode and estimates wavefront errors by using a cross-correlation or cross-coherence procedure that operates on the outputs of the sensor.Abstract:
An extended scene wavefront sensing apparatus and procedure that separates (deconvolves) scene effects from wavefront errors of an optical or similar system. The present wavefront sensing apparatus and procedure uses a point source wavefront slope sensor in scene scanning mode and estimates wavefront errors by using a cross-correlation or cross-coherence procedure that operates on the outputs of the point source wavefront slope sensor. A signal processing procedure employed by the point source wavefront slope sensor provides output signals corresponding to wavefront slopes at forward optics pupil locations geometrically projected to the location of the transmission and reflection measurement plane detector pairs. During the scanning process, each of the detector pairs (equivalent to a subaperture) measures the effects of the local unchanging wavefront error in the forward optical system and temporal variations due to the scanning scene. By cross correlating or cross-cohering each detector pair's temporal difference with differences from selected reference detector pairs, the scene induced variations in the measurement are eliminated, thereby leaving the stationary wavefront error component of the measurement. The lead/lag time in the temporal differences output between detector pairs and reference detector pairs are then used to estimate the wavefront slope differences between equivalent subapertures. The wavefront slope differences are used in a reconstructor to generate wavefront errors or wavefront slope errors, except for an unobservable global tilt.read more
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References
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Patent
Feedback controlled optics with wavefront compensation
TL;DR: In this paper, the sensitivity model of a complex optical system obtained by linear ray tracing is used to compute a control gain matrix by imposing the mathematical condition for minimizing the total wavefront error at the optical system's exit pupil.
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Piston error estimation method for segmented aperture optical systems while observing arbitrary unknown extended scenes
TL;DR: In this article, a method to reduce relative misalignments between segments of a multisegment optical system was proposed, in which elements of an arbitrary unknown extended scene image carried by an input beam were eliminated from the beam's error information in performing an error calculation.