US6233308B1
Expired / Lapsed
US
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Methods and apparatus for artifact compensation with variable angular sampling
Assignee: General Electric Co
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Filing: 1999-03-19
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Granted: 2001-05-15
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Expires: 2019-03-19
Abstract
Abstract The present invention, in one form, includes an imaging system having a x-ray source and a digital detector array. The system alters an angular spacing between samples of projection data as a function of the projection angle so that aliasing artifacts are reduced. More specifically and in one embodiment, after identifying at least two projection angle regions, a first view sampling rate is utilized to collect projection data for the first region. As the projection angle becomes equal to the second region, the view sampling rate is altered to a second view sampling rate. A complete volumetric image of an object is then generated from the data.
Inventors
- 👤 Jiang Hsieh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:00
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
81 words
A method for generating an image of an object using an imaging system, the imaging system including an x-ray detector array and a rotating x-ray source, the x-ray source projecting an x-ray beam toward the detector array along a projection angle, said method comprising the steps of: rotating the x-ray source through a plurality of projection angles; collecting a plurality of samples projection data; and altering an angular spacing between each projection data sample as a function of the projection angle.
Claim 2
Independent Claim
81 words
A method for generating an image of an object using an imaging system, the imaging system including an x-ray detector array and a rotating x-ray source, the x-ray source projecting an x-ray beam toward the detector array along a projection angle, said method comprising the steps of: rotating the x-ray source through a plurality of projection angles; collecting a plurality of samples projection data; and altering an angular spacing between each projection data sample as a function of the projection angle.
Claim 3
Dependent Claim
25 words
A method in accordance with claim 1 further comprising the step of generating a volumetric tomographic image of the entire object utilizing the projection data.
Claim 4
Dependent Claim
16 words
A method in accordance with claim 1 wherein the detector array is a digital detector panel.
Claim 5
Dependent Claim
36 words
A method in accordance with claim 1 wherein altering an angular spacing between each projection data sample as a function of the projection angle comprises the step of altering a rotational speed of the x-ray source.
Claim 6
Dependent Claim
36 words
A method in accordance with claim 1 wherein altering an angular spacing between each projection data sample as a function of the projection angle comprises the step of altering a sampling frequency of the detector array.
Claim 7
Dependent Claim
41 words
A method in accordance with claim 1 wherein altering an angular spacing between each projection data sample as a function of the projection angle comprises the steps of: identifying a first projection angle range; and identifying a second projection angle range.
Claim 8
Dependent Claim
51 words
A method in accordance with claim 6 wherein altering an angular spacing between each projection data sample further comprises the steps of: rotating the x-ray source at a first speed for the first projection angle range; and rotating the x-ray source at a second speed for the second projection angle range.
Claim 9
Dependent Claim
56 words
A method in accordance with claim 6 wherein the object includes at least one high density element having a sharp structure, wherein identifying a first projection angle region comprises the steps of: determining a sharp structure axis; and selecting a center of the first projection angle range to be approximately aligned along the sharp structure axis.
Claim 10
Dependent Claim
63 words
A method in accordance with claim 8 wherein the object high density element sharp structure axis is aligned with a patient y-axis, and wherein selecting a center of the first projection angle range to be approximately aligned along the sharp structure axis comprises the step of selecting a center of the first projection angle range to be approximately aligned with the patient y-axis.
Claim 11
Dependent Claim
62 words
A method in accordance with claim 6 wherein identifying a second projection angle comprises the step of identifying a second projection angle region center in accordance with: C SPAR = 180 degrees + C FPAR ; where: C SPAR = the second projection angle region center; and C FPAR = a first projection angle region center.
Claim 12
Dependent Claim
22 words
A method in accordance with claim 6 wherein further comprising the step of applying a weighting function to the collected projection data.
Claim 13
Dependent Claim
50 words
A method in accordance with claim 11 wherein applying weighting function to the projection data comprising the steps of: applying a first weight to the projection data collected from the first projection angle range; and applying a second weight to the projection data collected from the second projection angle range.
Claim 14
Dependent Claim
17 words
A method in accordance with claim 12 wherein the first weight is less than the second weight.
Claim 15
Dependent Claim
41 words
A method in accordance with claim 6 wherein the identifying a first projection angle range comprises the steps of: determining a starting angle; and selecting a center of the first projection angle range to be approximately aligned along the starting angle.
Claim 16
Dependent Claim
26 words
A method in accordance with claim 1 wherein collecting a plurality of samples of projection data comprises the step of interpolating the samples of projection data.
Claim 17
Dependent Claim
76 words
An imaging system for generating an image of an object, said imaging system comprising an x-ray detector array and a rotating x-ray source, said x-ray source projecting an x-ray beam toward said detector array along a projection angle, said system configured to: rotate said x-ray source through a plurality of projection angles; collect a plurality of samples projection data; and alter an angular spacing between each projection data sample as a function of the projection angle.
Claim 18
Dependent Claim
76 words
An imaging system for generating an image of an object, said imaging system comprising an x-ray detector array and a rotating x-ray source, said x-ray source projecting an x-ray beam toward said detector array along a projection angle, said system configured to: rotate said x-ray source through a plurality of projection angles; collect a plurality of samples projection data; and alter an angular spacing between each projection data sample as a function of the projection angle.
Claim 19
Dependent Claim
24 words
An imaging system in accordance with claim 16 further configured to generate a volumetric tomographic image of the entire object utilizing the projection data.
Claim 20
Dependent Claim
17 words
An imaging system in accordance with claim 16 wherein said detector array comprises a digital detector panel.
Claim 21
Dependent Claim
20 words
An imaging system in accordance with claim 18 wherein said detector array is approximately 40 cm by approximately 40 cm.
Claim 22
Dependent Claim
38 words
An imaging system in accordance with claim 16 wherein to alter an angular spacing between each projection data sample as a function of the projection angle, said system configured to alter a rotational speed of said x-ray source.
Claim 23
Dependent Claim
38 words
An imaging system in accordance with claim 16 wherein to alter an angular spacing between each projection data sample as a function of the projection angle, said system configured to alter a sampling frequency of said detector array.
Claim 24
Dependent Claim
43 words
An imaging system in accordance with claim 16 wherein to alter an angular spacing between each projection data sample as a function of the projection angle, said system configured to: identify a first projection angle range; and identify a second projection angle range.
Claim 25
Dependent Claim
53 words
An imaging system in accordance with claim 22 wherein to alter an angular spacing between each projection data sample, said system further configured to: rotate said x-ray source at a first speed for said first projection angle range; and rotate said x-ray source at a second speed for said second projection angle range.
Claim 26
Dependent Claim
58 words
An imaging system in accordance with claim 22 wherein the object includes at least one high density element having a sharp structure, wherein to identify a first projection angle region, said system configured to: determine a sharp structure axis; and select a center of the first projection angle range to be approximately aligned along the sharp structure axis.
Claim 27
Dependent Claim
61 words
An imaging system in accordance with claim 24 wherein the sharp structure axis is aligned with a patient y-axis, and wherein to select a center of the first projection angle range to be approximately aligned along the sharp structure axis, said system configured to select a center of the first projection angle range to be approximately aligned with the patient y-axis.
Claim 28
Dependent Claim
64 words
An imaging system in accordance with claim 22 wherein to identify a second projection angle, said system configured to identify a second projection angle region center in accordance with: C SPAR = 180 degrees + C FPAR ; where: C SPAR = the second projection angle region center; and C FPAR = a first projection angle region center.
Claim 29
Dependent Claim
23 words
An imaging system in accordance with claim 22 wherein said system further configured to apply a weighting function to the collected projection data.
Claim 30
Dependent Claim
53 words
An imaging system in accordance with claim 27 wherein to apply a weighting function to the projection data, said system configured to: apply a first weight to the projection data collected from said first projection angle range; and apply a second weight to the projection data collected from said second projection angle range.
Claim 31
Dependent Claim
18 words
An imaging system in accordance with claim 28 wherein said first weight is less than said second weight.
Claim 32
Dependent Claim
42 words
An imaging system in accordance with claim 22 wherein to identify a first projection angle range, said system configured to: determine a starting angle; and select a center of the first projection angle range to be approximately aligned along said starting angle.
Claim 33
Dependent Claim
28 words
An imaging system in accordance with claim 22 wherein to collect a plurality of samples of projection data, said system configured to interpolate said samples of projection data.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-05-14 | 2004-11-13 | 2005-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-14 | 2008-11-13 | 2009-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-14 | 2012-11-13 | 2013-05-15 | $7700.00 | Window Closed / Lapsed |