US 5,610,707 AGranted

Wavefront sensor for a staring imager

AssigneeLockheed Missiles & Space Company, Inc.

InventorsAlan L. Duncan, Daniel S. Acton, Richard L. Kendrick

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Abstract

A wavefront sensor for use in a staring imaging system for generating focused and defocused images of an object scene that is being imaged by the imaging system from a single input optical beam impinged thereon. The wavefront sensor includes a beamsplitter for splitting an optical input beam into identical first and second half beam portions and for focusing the first and second half beam portions onto respective first and second focal planes. A phase plate is interposed between the beamsplitter and the second focal plane for inducing a known focus error in the second half beam portion. A photodetector is also provided and is effective to form a best focused image and a slightly out of focus image at the first and second focal planes, respectively. The focused and defocused images are combinable using phase diversity techniques to estimate wavefront aberrations present in the imaging system.

Claims15

Dependent claims

In a staring imaging system, a wavefront sensor for generating focused and defocused images of an object scene that is being imaged by the imaging system from a single input optical beam impinged thereon, and wherein the focused and defocused images are combinable to estimate wavefront aberrations present in the imaging system, comprising:

a) beamsplitter means for splitting an optical input beam into identical first and second half beam portions and for focusing said first and second half beam portions onto respective first and second adjacent regions of a common focal plane, said optical input beam representing an object scene that is being imaged by the imaging system;
b) defocusing means disposed between said beamsplitter means and said second region of said focal plane for inducing a known field-independent focus error in said second half beam portion;
and
c) photodetector means disposed adjacent said first and second regions of said focal plane for converting photon energy associated with said first and second half beam portions into electronic signals representing a best focussed image and a defocused image of the object scene, respectively.

1 more element

a) an aperture-sharing assembly for splitting an optical input beam into identical first and second half beam portions and for focusing said first and second half beam portions onto respective first and second adjacent regions of a common focal plane, said optical input beam representing an object scene that is being imaged by the imaging system;
b) a light transmissive compensator plate disposed between said aperture-sharing assembly and said second region of said focal plane for inducing a known field-independent focus error in said second half beam portion;
and
c) a photodetector assembly disposed adjacent said first and second regions of said focal plane for converting photon energy associated with said first and second half beam portions into electronic signals representing a best focussed image and a defocused image of the object scene, respectively.

1 more element

Dependencies are inferred from the claim text.