US5818896A
Expired / Lapsed
US
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Methods and apparatus for three-dimensional and maximum intensity projection image reconstruction in a computed tomography system
Assignee: General Electric Co
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Filing: 1996-11-18
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Granted: 1998-10-06
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Expires: 2016-11-18
Abstract
Abstract The present invention, in one form, is a system for reducing noise artifacts in three-dimensional image reconstruction using data acquired in a helical scan. More specifically, a standard deviation ratio of reconstructed images with and without helical weighting is identified. Such standard deviation ratio is then used to generate filter coefficients, which are then applied to the data in an adaptive smoothing algorithm.
Inventors
- 👤 Jiang Hsieh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:32
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/027; G; G01; G01N; G01N23/00; G01N23/02; G01N23/04; G01N23/046; G01N2223/00; G01N2223/40; G01N2223/419; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
72 words
A system for generating an image of an object using data acquired in a helical scan, said system comprising an x-ray source and a detector array, said system configured to: determine a helical weighting function; determine a standard deviation ratio of reconstructed images with and without helical weighting; identify a filter coefficient based at least in part on the determined standard deviation ratio; and apply the identified filter coefficient to the data.
Claim 2
Independent Claim
72 words
A system for generating an image of an object using data acquired in a helical scan, said system comprising an x-ray source and a detector array, said system configured to: determine a helical weighting function; determine a standard deviation ratio of reconstructed images with and without helical weighting; identify a filter coefficient based at least in part on the determined standard deviation ratio; and apply the identified filter coefficient to the data.
Claim 3
Dependent Claim
22 words
A system in accordance with claim 1 wherein to identify the filter coefficient, said system is further configured to segment the data.
Claim 4
Dependent Claim
21 words
A system in accordance with claim 2 wherein to segment the data, said system is configured to perform grey scale thresholding.
Claim 5
Dependent Claim
16 words
A system in accordance with claim 1 further configured to generate a Maximum Intensity Projection image.
Claim 6
Dependent Claim
64 words
A system in accordance with claim 1 wherein said standard deviation ratio of reconstructed images with and without helical weighting is: ##EQU7## where: ω(γ,β) is the helical weighting function; σ(γ,β) is a standard deviation distribution function of the projection; β is a gantry angle; γ is a detector angle; L' is a projection distance between an x-ray source and a point of interest, (r,φ).
Claim 7
Dependent Claim
22 words
A system in accordance with claim 5 further comprising a 3×3 kernel, and wherein the filter coefficient is identified according to: ##EQU8##
Claim 8
Dependent Claim
14 words
A system in accordance with claim 1 further configured to generate a three-dimensional image.
Claim 9
Independent Claim
64 words
A method for generating an image of an object using data acquired in a helical scan, said method comprising the steps of: determining a helical weighting function; determining a standard deviation ratio of reconstructed images with and without helical weighting; identifying a filter coefficient based at least in part on the determined standard deviation ratio; and applying the identified filter coefficient to the data.
Claim 10
Independent Claim
64 words
A method for generating an image of an object using data acquired in a helical scan, said method comprising the steps of: determining a helical weighting function; determining a standard deviation ratio of reconstructed images with and without helical weighting; identifying a filter coefficient based at least in part on the determined standard deviation ratio; and applying the identified filter coefficient to the data.
Claim 11
Dependent Claim
18 words
A method in accordance with claim 8 further comprising the step of generating a Maximum Intensity Projection image.
Claim 12
Dependent Claim
19 words
A method in accordance with claim 8 wherein identifying the filter coefficient comprises the step of segmenting the data.
Claim 13
Dependent Claim
19 words
A method in accordance with claim 10 wherein segmenting the data comprises the step of performing grey scale thresholding.
Claim 14
Dependent Claim
16 words
A method in accordance with claim 8 further comprising the step of generating a three-dimensional image.
Claim 15
Dependent Claim
64 words
A method in accordance with claim 8 wherein the standard deviation ratio of reconstructed images with and without helical weighting is: ##EQU9## where: ω(γ,β) is the helical weighting function; σ(γ,β) is a standard deviation distribution function of the projection; β is a gantry angle; γ is a detector angle; L' is a projection distance between an x-ray source and a point of interest, (r,φ).
Claim 16
Dependent Claim
16 words
A method in accordance with claim 13 wherein the filter coefficient is identified according to: ##EQU10##
References Cited (Backward Citations)
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