Reprojection-based three-dimensional image reconstruction
First Claim
1. A method of reconstructing a three dimensional image from a set of X-ray projections generated by a scanning system, the image corresponding to a first volume segment that is a portion of a longer object, comprising:
- reconstructing, from the set of X-ray projections, a first estimate image of a second volume segment larger than the first volume segment, wherein the second volume segment includes the first volume segment;
applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image;
re-projecting the hypothetical object image so as to produce a set of simulated projections;
combining the projections generated by the scanning system and simulated re-projections to give hybrid projections corresponding to the first volume segment only;
reconstructing the hybrid projections so as to produce a three dimensional image corresponding to the first volume segment.
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Abstract
A method of reconstructing a three-dimensional image from a set of X-ray projections generated by a scanning system, where the image corresponds to a first volume segment that is a portion of a longer object, includes reconstructing a first estimate image of a second volume segment larger than the first volume segment. The second volume segment includes the first volume segment. The method also includes applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image. The method further includes re-projecting the hypothetical object image so as to produce a set of simulated hybrid projections corresponding to the first volume segment. The method also includes reconstructing the hybrid projections so as to produce a three-dimensional image corresponding to the first volume segment.
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Citations
30 Claims
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1. A method of reconstructing a three dimensional image from a set of X-ray projections generated by a scanning system, the image corresponding to a first volume segment that is a portion of a longer object, comprising:
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reconstructing, from the set of X-ray projections, a first estimate image of a second volume segment larger than the first volume segment, wherein the second volume segment includes the first volume segment;
applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image;
re-projecting the hypothetical object image so as to produce a set of simulated projections;
combining the projections generated by the scanning system and simulated re-projections to give hybrid projections corresponding to the first volume segment only;
reconstructing the hybrid projections so as to produce a three dimensional image corresponding to the first volume segment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for reconstructing a three dimensional image from a set of X-ray projections generated by a scanning system, the image corresponding to a first volume segment that is a portion of a longer object, comprising:
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a first reconstruction processor for reconstructing, from the set of X-ray projections, a first estimate image of a second volume segment larger than the first volume segment, wherein the second volume segment includes the first volume segment;
a masking processor for applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image;
a re-projection processor for re-projecting the hypothetical object image so as to produce a set of simulated projections;
a combination processor for combining the projections generated by the scanning system and the simulated projections to produce a set of hybrid projections corresponding to the first volume segment;
a second reconstruction processor for reconstructing the hybrid projections so as to produce a three dimensional image corresponding to the first volume segment. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A system for reconstructing a three dimensional image from a set of X-ray projections generated by a scanning system, the image corresponding to a first volume segment that is a portion of a longer object, comprising:
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means for reconstructing, from the set of X-ray projections, a first estimate image of a second volume segment larger than the first volume segment, wherein the second volume segment includes the first volume segment;
means for applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image;
means for re-projecting the hypothetical object image so as to produce a set of simulated hybrid projections corresponding to the first volume segment;
means for reconstructing the hybrid projections so as to produce a three dimensional image corresponding to the first volume segment.
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29. A method of reconstructing a three dimensional image from a set of X-ray projections generated by a scanning system, the image corresponding to a first volume segment that is a portion of a longer object, comprising:
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reconstructing, via an approximate reconstruction algorithm including a Helical Feldkamp algorithm, a first estimate image of a second volume segment larger than the first volume segment, wherein the second volume segment includes the first volume segment, the second volume segment is larger than the first volume segment, and (i) the first volume segment is disposed in a middle portion of the second volume segment, such that a first region ROI includes an intersection of the first volume segment and the second volume segment, and a second region {overscore (ROI)} include those portions of the second volume that do not intersect the first volume;
applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image, by applying binary coefficients substantially equal to zero to portions of the first estimate image corresponding to the first volume segment, and applying binary coefficients substantially equal to one elsewhere;
re-projecting the hypothetical object image, via a computer simulation using parameters corresponding to the geometry of the scanning system, so as to produce a set of simulated hybrid projections corresponding to the first volume segment;
reconstructing the hybrid projections by executing a Radon transform inversion or a filtered back-projection algorithm so as to produce a three dimensional image corresponding to the first volume segment.
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30. A system for reconstructing a three dimensional image from a set of X-ray projections generated by a scanning system, the image corresponding to a first volume segment that is a portion of a longer object, comprising:
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a first reconstruction processor for reconstructing, from the set of X-ray projections and via an approximate reconstruction algorithm including a Helical Feldkamp algorithm, a first estimate image of a second volume segment larger than the first volume segment, wherein the second volume segment includes the first volume segment, the second volume segment is larger than the first volume segment, and (i) the first volume segment is disposed in a middle portion of the second volume segment, such that a first region ROI includes an intersection of the first volume segment and the second volume segment, and a second region {overscore (ROI)} include those portions of the second volume that do not intersect the first volume;
a masking processor for applying a weighting function to the first estimate image for masking the first volume segment, so as to produce a hypothetical object image, by applying binary coefficients substantially equal to zero to portions of the first estimate image corresponding to the first volume segment, and applying binary coefficients substantially equal to one elsewhere;
a re-projection processor for re-projecting the hypothetical object image, via a computer simulation using parameters corresponding to the geometry of the scanning system, so as to produce a set of simulated hybrid projections corresponding to the first volume segment;
a second reconstruction processor for reconstructing the hybrid projections by executing a Radon transform inversion or a filtered back-projection algorithm so as to produce a three dimensional image corresponding to the first volume segment.
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Specification