Optical element, device, method, and applications
AssigneeUniversity of Rochester
InventorsWanli Chi, Nicholas George
Life of this patent
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Abstract
A novel phase-coded aperture, associated imaging system, and design method is disclosed. The optical imaging system includes a coded-aperture followed optically by a detector array and includes an image processor. A diffraction pattern in the form of a band-limited uniformly redundant array is formed on the detector array when focusable radiation from a point source in object space is modulation by the transmission function of the coded-aperture. Since diffraction effects cannot be ignored in the optical regime, an iterative phase retrieval method is used to calculate the phase-coded aperture transmission function. Correlation type processing can be applied for the image recovery.
Claims28
An optical element for generating a band-limited uniformly redundant array (bl-URA) from light within a spectrum of focusable radiation, comprising:
- an optical element characterized by a light transmission function, P(ξ, η), such that light within the spectrum of focusable radiation incident on the optical element from a point location in an object space of the optical element is optically transformed by P(ξ, η) into a band-limited uniformly redundant array (bl-URA), A(x,y), in an image space of the optical element.
An optical imaging device, consisting of:
- an optical element characterized by a light transmission function, P(ξ, η), such that light within the spectrum of focusable radiation incident on the optical element from a point location in an object space of the optical element is optically transformed by P(ξ, η) into a band-limited uniformly redundant array (bl-URA), A(x,y), in an image space of the optical element;
- a detector disposed in the image space such that the bl-URA is formed on the detector;
- and
- an image processor adapted to recover an image of an object from the detected bl-URA.
A method for determining a transmission function P(ξ, η) for an optical element that will generate a desired intensity pattern A(x,y) on a detector from light within a spectrum of focusable radiation from a point on an object, comprising:
- a) determining a real, non-negative, band-limited uniformly redundant array, A(x,y), that will be generated on a detector by an optical element characterized by a transmission function P(ξ, η), from light within the spectrum of focusable radiation from a point on the object;
- b) defining an electric field having an amplitude E(x,y)=[A(x,y)]1/2;
- c) calculating the transmission function P(ξ, η) in a plane immediately adjacent a known position of the optical element by performing a free space back propagation, and denoting the transmission function |P(ξ, η)|exp[iφ(ξ,η)];
- d) determining an electric field at a known detector plane location by performing a free space propagation, and denoting this electric field F(x,y)exp[iψ(x,y)];
- e) applying a detector plane intensity constraint by setting F(x,y)→[A(x,y)]1/2;
- f) performing another free space back propagation;
- and
- g) calculating the optical element transmission function P(ξ, η) that will generate the desired intensity pattern A(x,y).
Dependencies are inferred from the claim text.