US4636952A
Expired / Lapsed
US
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Method and apparatus for back projection image reconstruction using virtual equi-spaced detector array
Assignee: General Electric Co
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Filing: 1984-12-03
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Granted: 1987-01-13
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Expires: 2004-12-03
Abstract
Abstract Image reconstruction in a tomographic scanning system using a fan beam of radiation and a curved equi-angular detector array is facilitated by mapping signals from the curved array into a virtual equi-spaced planar detector array. Back projection image reconstruction algorithms are simplified by using the signals from the virtual equi-spaced planar array.
Inventors
- 👤 Carl R. Crawford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 22:02
CPC Classifications
G; G06; G06T; G06T12/00; G06T12/10; G06T2211/00; G06T2211/40; G06T2211/421; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
73 words
In a tomographic system using a fan beam radiation source and a curved equi-angular detector array for detecting attenuated radiation, an improved method of image reconstruction comprising the steps of mapping unfiltered signals of attenuated radiation from said curved equi-angular detector array into signals for a virtual equi-spaced planar detector array, filtering said signals for a virtual equi-spaced planar detector, and reconstructing an image based on said filtered signals for said virtual array.
Claim 2
Dependent Claim
73 words
In a tomographic system using a fan beam radiation source and a curved equi-angular detector array for detecting attenuated radiation, an improved method of image reconstruction comprising the steps of mapping unfiltered signals of attenuated radiation from said curved equi-angular detector array into signals for a virtual equi-spaced planar detector array, filtering said signals for a virtual equi-spaced planar detector, and reconstructing an image based on said filtered signals for said virtual array.
Claim 3
Dependent Claim
33 words
The method as defined by claim 1 wherein said step of mapping signals comprises interpolating a plurality of signals from said curved equi-angular detector array for deriving each signal for said virtual array.
Claim 4
Dependent Claim
13 words
The method as defined by claim 2 wherein said interpolating comprises linear interpolating.
Claim 5
Dependent Claim
13 words
The method as defined in claim 2 wherein said interpolating comprises Lagrange interpolation.
Claim 6
Dependent Claim
64 words
In a tomographic system using a fan beam radiation source and curved equi-angular detector array for detecting attenuated radiation, a method of modifying unfiltered signals from said curved equi-angular detector array before image reconstruction comprising the steps of defining a virtual equi-spaced planar detector array, and mapping said signals from said curved equi-angular detector array into signals for said virtual equi-spaced planar detector array.
Claim 7
Dependent Claim
64 words
In a tomographic system using a fan beam radiation source and curved equi-angular detector array for detecting attenuated radiation, a method of modifying unfiltered signals from said curved equi-angular detector array before image reconstruction comprising the steps of defining a virtual equi-spaced planar detector array, and mapping said signals from said curved equi-angular detector array into signals for said virtual equi-spaced planar detector array.
Claim 8
Dependent Claim
33 words
The method as defined by claim 5 wherein said step of mapping signals comprises interpolating a plurality of signals from said curved equi-angular detector array for deriving each signal for said virtual array.
Claim 9
Dependent Claim
13 words
The method as defined by claim 6 wherein said interpolating comprises linear interpolation.
Claim 10
Dependent Claim
13 words
The method as defined by claim 6 wherein said interpolating comprises Lagrange interpolations.
Claim 11
Dependent Claim
70 words
In a tomographic system using a fan beam radiation source, means for generating signals for use in image reconstruction by backprojection comprising a curved equi-angular detector array for detecting radiation with each detector of said curved array generating an electrical signal in response to detected radiation, and means for mapping said signals from said curved array into signals for a virtual equi-spaced planar detector array for use in back projections.
Claim 12
Dependent Claim
70 words
In a tomographic system using a fan beam radiation source, means for generating signals for use in image reconstruction by backprojection comprising a curved equi-angular detector array for detecting radiation with each detector of said curved array generating an electrical signal in response to detected radiation, and means for mapping said signals from said curved array into signals for a virtual equi-spaced planar detector array for use in back projections.
Claim 13
Dependent Claim
34 words
Means for generating signals as defined by claim 9 wherein said means for mapping interpolates values of a plurality of signals from said curved array in mapping a signal for said virtual planar array.
Claim 14
Dependent Claim
35 words
Means for generating signals as defined by claim 10 wherein said means for mapping linearly interpolates values of a plurality of signals from said curved array in mapping a signal for said virtual planar array.
Claim 15
Dependent Claim
18 words
Means for generating signals as defined by claim 11 wherein said means for mapping interpolates by Lagrange interpolation.
References Cited (Backward Citations)
US4222104A
Cited
US4460961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |