US6272200B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fourier and spline-based reconstruction of helical CT images
Assignee: Arch Development Corp
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Filing: 1999-07-28
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Granted: 2001-08-07
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Expires: 2019-07-28
Abstract
Abstract A method and apparatus are provided for reconstructing a set of CT images from helical CT data. The method includes the steps of receiving the helical CT data and generating a set of fan-beam sinograms at equally spaced longitudinal positions. The method further includes the steps of estimating a set of parallel-beam sinograms from the generated set of fan-beam sinograms and reconstructing the CT images using a parallel beam reconstruction algorithm.
Inventors
- 👤 Xiaochuan Pan
- 👤 Patrick Jean La Riviere
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:47
CPC Classifications
G; G06; G06T; G06T12/00; G06T12/10; A; A61; A61B; A61B6/00; A61B6/02; A61B6/027; A61B6/58; A61B6/582; A61B6/583; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
60 words
A method of reconstructing a set of CT images from helical CT data, such method comprising the steps of: receiving the helical CT data; generating a set of fan-beam sinograms at equally spaced longitudinal positions; and estimating a set of parallel-beam sinograms from the generated set of fan-beam sinograms; and reconstructing the CT images using a parallel beam reconstruction algorithm.
Claim 2
Independent Claim
60 words
A method of reconstructing a set of CT images from helical CT data, such method comprising the steps of: receiving the helical CT data; generating a set of fan-beam sinograms at equally spaced longitudinal positions; and estimating a set of parallel-beam sinograms from the generated set of fan-beam sinograms; and reconstructing the CT images using a parallel beam reconstruction algorithm.
Claim 3
Dependent Claim
50 words
The method of reconstructing the set of CT images as in claim 1 wherein the step of generating the set of fan-beam sinograms further comprises translating the longitudinal sampling grid of the helical CT data at each view angle to conform to a predetermined set of equally spaced longitudinal positions.
Claim 4
Dependent Claim
34 words
The method of reconstructing the set of CT images as in claim 2 wherein the step of translating the longitudinal sampling grid of the helical CT data further comprises using a Fourier shift theorem.
Claim 5
Dependent Claim
34 words
The method of reconstructing the set of CT images as in claim 3 wherein the step of translating the longitudinal sampling grid using the Fourier shift theorem further comprises multiplication by an apodization window.
Claim 6
Dependent Claim
33 words
The method of reconstructing the set of CT images as in claim 3 wherein the step of translating the longitudinal sampling grid using the Fourier shift theorem further comprises using Fourier-domain deconvolution techniques.
Claim 7
Dependent Claim
42 words
The method of reconstructing the set of CT images as in claim 3 wherein the step of translating the longitudinal sampling grid using the Fourier shift theorem further comprises solving a set of frequency-domain equations in the case of multiple detector rows.
Claim 8
Dependent Claim
32 words
The method of reconstructing the set of CT images as in claim 1 further comprising augmenting the received helical CT data using the redundancy of fanbeam data over a 2π data interval.
Claim 9
Dependent Claim
43 words
The method of reconstructing the set of CT images as in new claim 7 wherein use of the redundant data further comprises aligning the redundant data with the directly measured data using the Fourier shift theorem and solving a set of frequency-space equations.
Claim 10
Dependent Claim
39 words
The method of reconstructing the set of CT images as in claim 1 wherein the step of generating the set of fan-beam sinograms further comprises fitting a continuous curve to a set of longitudinal samples of the helical data.
Claim 11
Dependent Claim
31 words
The method of reconstructing the set of CT images as in claim 9 wherein the step of fitting a continuous curve further comprises fitting a spline to the helical CT data.
Claim 12
Dependent Claim
32 words
The method of reconstructing the set of CT images as in claim 10 wherein the step of fitting a spline to the helical data further comprises interpolating the data with the spline.
Claim 13
Dependent Claim
86 words
The method of reconstructing the set of CT images as in claim 10 wherein the step of fitting a spline to the helical data further comprises finding the minimizer of: Φ ( g ) = ∑ k = 0 NR - 1 W k [ y k - g ^ ( z k ) ] 2 + α ∫ z a z b [ g ^ ″ ( z k ) ] 2 z .
Claim 14
Dependent Claim
96 words
The method of reconstructing the set of CT images as in claim 10 wherein the step of fitting a spline to the helical data further comprises finding the minimizer of: Φ ( g ) = ∑ k = 0 NR - 1 W k [ y k - ∫ z k l z k r g ^ ( z ) z ] 2 + α ∫ z a z b [ g ^ ″ ( z ) ] 2 z .
Claim 15
Dependent Claim
31 words
The method of reconstructing the set of CT images as in claim 10 further comprising augmenting the received helical data using the redundancy of fanbeam data over a 2π data interval.
Claim 16
Dependent Claim
43 words
The method of reconstructing the set of CT images as in claim 9 wherein the step of fitting a continuous curve to a set of longitudinal samples of the helical data further comprises resampling the continuous curve at the equally spaced longitudinal positions.
Claim 17
Dependent Claim
64 words
Apparatus for reconstructing a set of CT images from helical CT data, such apparatus comprising: means for receiving the helical CT data; means for generating a set of fan-beam sinograms at equally spaced longitudinal positions; and means for estimating a set of parallel-beam sinograms from the generated set of fan-beam sinograms; and means for reconstructing the CT images using a parallel beam reconstruction algorithm.
Claim 18
Dependent Claim
64 words
Apparatus for reconstructing a set of CT images from helical CT data, such apparatus comprising: means for receiving the helical CT data; means for generating a set of fan-beam sinograms at equally spaced longitudinal positions; and means for estimating a set of parallel-beam sinograms from the generated set of fan-beam sinograms; and means for reconstructing the CT images using a parallel beam reconstruction algorithm.
Claim 19
Dependent Claim
52 words
The apparatus for reconstructing the set of CT images as in claim 16 wherein the means for generating the set of fan-beam sinograms further comprises means for translating the longitudinal sampling grid of the helical CT data at each view angle to conform to a predetermined set of equally spaced longitudinal positions.
Claim 20
Dependent Claim
36 words
The apparatus for reconstructing the set of CT images as in claim 17 wherein the means for translating the longitudinal sampling grid of the helical CT data further comprises means for using a Fourier shift theorem.
Claim 21
Dependent Claim
36 words
The apparatus for reconstructing the set of CT images as in claim 18 wherein the means for translating the longitudinal sampling grid using the Fourier shift theorem further comprises means for multiplication by an apodization window.
Claim 22
Dependent Claim
35 words
The apparatus for reconstructing the set of CT images as in claim 18 wherein the means for translating the longitudinal sampling grid using the Fourier shift theorem further comprises means for using Fourier-domain deconvolution techniques.
Claim 23
Dependent Claim
44 words
The apparatus for reconstructing the set of CT images as in claim 18 wherein the means for translating the longitudinal sampling grid using the Fourier shift theorem further comprises means for solving a set of frequency-domain equations in the case of multiple detector rows.
Claim 24
Dependent Claim
34 words
The apparatus for reconstructing the set of CT images as in claim 16 further comprising means for augmenting the received helical CT data using the redundancy of fanbeam data over a 2π data interval.
Claim 25
Dependent Claim
47 words
The apparatus for reconstructing the set of CT images as in new claim 22 wherein the means for augmenting the redundant data further comprises means for aligning the redundant data with the directly measured data using the Fourier shift theorem and solving a set of frequency-space equations.
Claim 26
Dependent Claim
41 words
The apparatus for reconstructing the set of CT images as in claim 16 wherein the means for generating the set of fan-beam sinograms further comprises means for fitting a continuous curve to a set of longitudinal samples of the helical data.
Claim 27
Dependent Claim
33 words
The apparatus for reconstructing the set of CT images as in claim 24 wherein the means for fitting a continuous curve further comprises means for fitting a spline to the helical CT data.
Claim 28
Dependent Claim
34 words
The apparatus for reconstructing the set of CT images as in claim 25 wherein the means for fitting a spline to the helical data further comprises means for interpolating the data with the spline.
Claim 29
Dependent Claim
88 words
The apparatus for reconstructing the set of CT images as in claim 25 wherein the means for fitting a spline to the helical data further comprises means for finding the minimizer of: Φ ( g ) = ∑ k = 0 NR - 1 W k [ y k - g ^ ( z k ) ] 2 + α ∫ z a z b [ g ^ ″ ( z k ) ] 2 z .
Claim 30
Dependent Claim
98 words
The apparatus for reconstructing the set of CT images as in claim 25 wherein the means for fitting a spline to the helical data further comprises means for finding the minimizer of: Φ ( g ) = ∑ k = 0 NR - 1 W k [ y k - ∫ z k l z k r g ^ ( z ) z ] 2 + α ∫ z a z b [ g ^ ″ ( z ) ] 2 z .
Claim 31
Dependent Claim
33 words
The apparatus for reconstructing the set of CT images as in claim 25 further comprising means for augmenting the received helical data using the redundancy of fanbeam data over a 2π data interval.
Claim 32
Dependent Claim
45 words
The apparatus for reconstructing the set of CT images as in claim 24 wherein the means for fitting a continuous curve to a set of longitudinal samples of the helical data further comprises means for resampling the continuous curve at the equally spaced longitudinal positions.
Claim 33
Dependent Claim
75 words
Apparatus for reconstructing a set of CT images from helical CT data, such apparatus comprising: a memory adapted to receive the helical CT data; a sinogram processor adapted to generate a set of fan-beam sinograms at equally spaced longitudinal positions; and an estimator processor adapted to estimate a set of parallel-beam sinograms from the generated set of fan-beam sinograms; and a reconstruction processor adapted to reconstruct the CT images using a parallel beam reconstruction algorithm.
Claim 34
Dependent Claim
75 words
Apparatus for reconstructing a set of CT images from helical CT data, such apparatus comprising: a memory adapted to receive the helical CT data; a sinogram processor adapted to generate a set of fan-beam sinograms at equally spaced longitudinal positions; and an estimator processor adapted to estimate a set of parallel-beam sinograms from the generated set of fan-beam sinograms; and a reconstruction processor adapted to reconstruct the CT images using a parallel beam reconstruction algorithm.
Claim 35
Dependent Claim
49 words
The apparatus for reconstructing the set of CT images as in claim 31 wherein the sinogram processor further comprises a translation processor adapted to translate the longitudinal sampling grid of the helical CT data at each view angle to conform to a predetermined set of equally spaced longitudinal positions.
Claim 36
Dependent Claim
29 words
The apparatus for reconstructing the set of CT images as in claim 32 wherein the translation processor further comprises a Fourier processor adapted to use a Fourier shift theorem.
Claim 37
Dependent Claim
32 words
The apparatus for reconstructing the set of CT images as in claim 33 wherein the translation processor further comprises an apodization processor adapted to multipliply the sampling grid by an apodization window.
Claim 38
Dependent Claim
28 words
The apparatus for reconstructing the set of CT images as in claim 33 wherein the translation processor further comprises a deconvolution processor adapted to use Fourier-domain deconvolution techniques.
Claim 39
Dependent Claim
37 words
The apparatus for reconstructing the set of CT images as in claim 33 wherein the translation processor further comprises a frequency-domain processor adapted to solve a set of frequency-domain equations in the case of multiple detector rows.
Claim 40
Dependent Claim
39 words
The apparatus for reconstructing the set of CT images as in claim 31 wherein the sinogram processor further comprises a curve fitting processor adapted to fit a continuous curve to a set of longitudinal samples of the helical data.
Claim 41
Dependent Claim
33 words
The apparatus for reconstructing the set of CT images as in claim 37 wherein the curve fitting processor further comprises a spline procesor adapted to fit a spline to the helical CT data.
Claim 42
Dependent Claim
30 words
The apparatus for reconstructing the set of CT images as in claim 38 wherein the spline processor further comprises an interpolating processor adapted to interpolate the data with the spline.
Claim 43
Dependent Claim
85 words
The apparatus for reconstructing the set of CT images as in claim 38 wherein the spline processor further comprises a first arithmetic unit adapted to find the minimizer of: Φ ( g ) = ∑ k = 0 NR - 1 W k [ y k - g ^ ( z k ) ] 2 + α ∫ z a z b [ g ^ ″ ( z k ) ] 2 z .
Claim 44
Dependent Claim
95 words
The apparatus for reconstructing the set of CT images as in claim 38 wherein the spline processor further comprises a second arithmetic unit adapted to find the minimizer of: Φ ( g ) = ∑ k = 0 NR - 1 W k [ y k - ∫ z k l z k r g ^ ( z ) z ] 2 + α ∫ z a z b [ g ^ ″ ( z ) ] 2 z .
Claim 45
Dependent Claim
35 words
The apparatus for reconstructing the set of CT images as in claim 37 wherein the curve fitting processor further comprises a resampling processor adapted to resample the continuous curve at the equally spaced longitudinal positions.
References Cited (Backward Citations)
US5406479A
Cited
US6108575A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-06 | 2005-02-05 | 2005-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-06 | 2009-02-05 | 2009-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-06 | 2013-02-05 | 2013-08-07 | $7700.00 | Window Closed / Lapsed |