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US 9,801,591 B2Granted
Fast iterative algorithm for superresolving computed tomography with missing data
AssigneeLickenbrock Technologies, LLC
InventorsTimothy J. Holmes, Sean M. Larkin
Life of this patent
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Abstract
Disclosed is a method, program product, and computer system that provides iterative computed tomography (CT) image reconstruction. The approach produces an image whose resolving power exceeds that of conventional algorithms, and utilizes an inner and out iterative loop, configured by ordered subsets criteria, to perform: projecting a reconstructed image; resampling a resulting calculated projection, thereby enabling super-resolution; calculating a comparison quantity with the collected projection array (e.g., sinogram); backprojecting onto a correction array a function that utilizes the comparison quantity; and generating a new reconstructed image with an operation involving the correction array.
Claims19
A method for reconstructing an image implemented on a computing system, comprising:
- inputting a collected projection array p(r,θ) produced from a computed tomography (CT) system imaging an object defined with a multi-dimensional image function ƒ(x);
- generating an initial reconstructed image ƒR(x);
- decomposing indices r,θ of the collected projection array into a collection of subsets;
- utilizing an iterative loop to sequentially process each of the subsets, wherein a processing sequence of the subsets is determined based on an ordered subset criteria, and wherein the process includes:
- projecting the reconstructed image ƒR(x) onto a calculated projection array pR(r,θ), wherein r,θ are indices for a current subset;
- calculating a comparison quantity q(r,θ), calculated from a calculated projection array pR(r,θ) and the collected projection array p(r,θ);
- backprojecting onto a correction array b(x) a function that utilizes the comparison quantity q(r,θ), wherein the comparison quantity is expressed as a ratio with a numerator term being expressed at least in part by a term that contains the collected projection array p(r,θ) and a denominator term being expressed at least in part by a term that contains reprojected data denoted by a calculated projection array pR(r,θ);
- generating a correction factor based on the correction array b(x);
- generating a new reconstructed image ƒR(x) that is modified from a previous reconstructed image by an operation involving the correction array b(x);
- wherein the new reconstructed image is enhanced to a finer resolution;
- and
- wherein a smoothing operation is applied to a calculated projection array pR(r,θ);
- and
- outputting a final image ƒR(x).
11 more elements
A program product stored on a non-transitory computer readable storage medium, which when executed by a computer system, reconstructs an image, comprising:
- program code for inputting a collected projection array p(r,θ) produced from a computed tomography (CT) system imaging an object defined with a multi-dimensional image function ƒ(x);
- program code for generating an initial reconstructed image ƒR(x);
- program code for decomposing the indices r,θ of the collected projection array into a collection of subsets;
- program code for implementing an iterative loop to sequentially process each of the subsets, wherein a processing sequence of the subsets is determined based on an ordered subset criteria, and wherein the process includes:
- projecting the reconstructed image ƒR(x) onto a calculated projection array pR(r,θ), wherein r,θ are indices for a current subset;
- calculating a comparison quantity q(r,θ), calculated from a projection array pR(r,θ) and the collected projection array p(r,θ);
- backprojecting onto a correction array b(x) a function that utilizes the comparison quantity q(r,θ), wherein the comparison quantity is expressed as a ratio with a numerator term being expressed at least in part by a term that contains the collected projection array p(r,θ) and a denominator term being expressed at least in part by a term that contains reprojected data of a calculated projection array pR(r,θ);
- generating a correction factor based on the correction array b(x);
- generating a new reconstructed image ƒR(x) that is modified from a previous reconstructed image using an operation involving the correction array b(x);
- wherein the new reconstructed image is enhanced to a finer resolution;
- and
- wherein a smoothing operation is applied to a calculated projection array pR(r,θ);
- and
- program code for outputting a final image ƒR(x).
11 more elements
A computer system for reconstructing an image implemented on a computing system, comprising:
- a processor and a memory;
- a system for inputting a collected projection array p(r,θ), produced from a computed tomography (CT) system imaging an object defined with a multi-dimensional image function ƒ(x);
- a system for generating an initial reconstructed image ƒR(x),
- a system for decomposing indices r,θ of the collected projection array into a collection of subsets;
- a system for utilizing an iterative loop to sequentially process each of the subsets, wherein a processing sequence of the subsets is determined based on an ordered subset criteria, and wherein the process includes:
- projecting the reconstructed image ƒR(x) onto a calculated projection array pR(r,θ) wherein r,θ are indices for a current subset;
- calculating a comparison quantity q(r,θ), calculated from a calculated projection array pR(r,θ) and the collected projection array p(r,θ);
- backprojecting onto a correction array b(x), a function that utilizes the comparison quantity q(r,θ), wherein the comparison quantity is expressed as a ratio with a numerator term being expressed at least in part by a term that contains the collected projection array p(r,θ) and a denominator term being expressed at least in part by a term that contains reprojected data of a calculated projection array pR(r,θ);
- generating a correction factor based on the correction array b(x);
- generating a new reconstructed image ƒR(x) that is modified from a previous reconstructed image using an operation involving the correction array b(x);
- wherein the new reconstructed image is enhanced to a finer resolution;
- and
- wherein a smoothing operation is applied to a calculated projection array pR(r,θ);
- and
- a system for outputting a final image ƒR(x).
12 more elements
Dependencies are inferred from the claim text.