Non-positive-definite optical filtering from positive-definite transfer functions
OwnerLester F. Ludwiginventor
Life of this patent
Estimating the term…
Abstract
Fractional Fourier transform properties of lenses or other optical environments are applied to one or more positive-definite optical transfer functions at locations outside the Fourier plane to realize or closely approximate arbitrary non-positive-definite transfer functions varying in both amplitude and phase. Controllable filter elements can be employed to create controllable optical processors which may be used for image filtering and optical computations using complex-valued arithmetic for monochromatic, color, and wide-spectrum optical signals. Applications include integrated optics, optical computing systems, particle beam systems, radiation accelerators, astronomical observation systems, and controllable lens systems.
Claims43
An optical filtering system comprising:
- a first optical element adapted to receive an original image requiring filtering;
- a second optical element positioned relative to said first optical element to define an optical region therebetween, said optical region comprising a Fourier transform plane and an optical region outside said Fourier transform plane;
- and
- a positive-definite optical transfer function element positioned within said optical region outside said Fourier transform plane, wherein said positive-definite optical transfer function element introduces a non-positive-definite transfer function on said original image to produce a modified image.
An optical filtering method comprising:
- receiving an original image requiring filtering at a first optical element;
- positioning a second optical element relative to said first optical element to define an optical region therebetween, said optical region comprising a Fourier transform plane and an optical region outside said Fourier transform plane;
- and
- positioning a positive-definite optical transfer function element within said optical region outside said Fourier transform plane, wherein said positive-definite optical transfer function element introduces a non-positive-definite transfer function on said original image to produce a modified image.
An optical filtering method comprising:
- receiving an original image requiring filtering at a first optical element;
- inducing a Fourier transform plane within an optical region defined by a second optical element positioned relative to said first optical element, said optical region comprising said Fourier transform plane and a region outside said Fourier transform plane;
- and
- introducing a non-positive-definite transfer function on said original image using a positive-definite optical transfer function element positioned within said region outside said Fourier transform plane, wherein said introducing of said non-positive-definite transfer function results in a filtered image of said original image.
Dependencies are inferred from the claim text.