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US 7,609,441 B2Granted
Distorted pupil relay for spectral filtering
AssigneeThe Boeing Company
InventorMark A. Lundgren
Life of this patent
Estimating the term…
Abstract
A system and method for spectral filtering of images are provided. The system and method utilize a first biconic lens surface to astigmatize a substantially 2-D system pupil into a substantially 1-D pupil (e.g., slit-shaped), and a second biconic lens surface to restore the astigmatic pupil to good quality. Advantageously, the light stream may be filtered with a variable filter.
Claims19
An optical system, comprising:
- a first biconic surface that receives a plurality of light ray bundles originating from a two-dimensional image of an object, the first biconic surface distorting a pupil from a circular shape to a slit shape thereby compressing the plurality of light ray bundles into a compressed beam of light with a slit-shaped cross-section;
- a variable filter for filtering the compressed beam of light;
- and
- a secondary group of biconic surfaces that corrects aberrations from the filtered beam of light and provides a filtered two-dimensional image at an image focal plane, the secondary group of biconic surfaces including a weak biconic surface and a strong biconic surface.
1 more element
An optical system, comprising:
- a first relay lens for providing an intermediate two-dimensional image of an object through a circular system stop;
- a first biconic lens group optically coupled to the first relay lens, the first biconic lens group receiving a plurality of light ray bundles originating from the intermediate two-dimensional image and distorting a pupil from a circular shape to a slit shape thereby compressing the plurality of light ray bundles into a compressed beam of light with a slit-shaped cross-section;
- a second relay lens optically coupled to the first biconic lens group for relaying the compressed beam of light;
- a variable filter optically coupled to the second relay lens for filtering the compressed beam of light;
- and a second biconic lens group optically coupled to the variable filter for correcting aberrations from the filtered beam of light to restore a filtered two-dimensional image at an image focal plane, the second biconic lens group including a weak biconic surface and a strong biconic surface.
2 more elements
A method of spectral filtering, comprising:
- receiving a plurality of light ray bundles originating from a two-dimensional image of an object at a first biconic surface;
- distorting a pupil from a circular shape to a slit shape with the first biconic surface thereby compressing the plurality of light ray bundles into a compressed beam of light with a slit-shaped cross-section;
- filtering the compressed beam of light;
- and
- correcting aberrations from the filtered beam of light with a secondary group of biconic surfaces to provide a filtered two-dimensional image at an image focal plane, the secondary group of biconic surfaces including a weak biconic surface and a strong biconic surface.
2 more elements
A pupil relay system, comprising:
- a first lens group for receiving a plurality of light ray bundles originating from a two-dimensional image of an object, the plurality of light ray bundles produced by an optical system having an aperture stop, the first lens group including a first biconic surface capable of inducing an astigmatic pupil of the stop;
- and a second lens group that reduces the astigmatism induced by the first biconic surface and provides a filtered two-dimensional image at an image focal plane, the second lens group including a weak biconic surface and a strong biconic surface.
Dependencies are inferred from the claim text.