US5909477A
Expired / Lapsed
US
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Computed tomography scanning target detection using non-parallel slices
Assignee: Analogic Corp
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Filing: 1997-10-10
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Granted: 1999-06-01
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Expires: 2017-10-10
Abstract
Abstract A nutating slice CT image reconstruction apparatus and method generates a set of projection data using helical cone-beam scanning. The three-dimensional projection data is used to reconstruct a series of planar image slices. The slices are selected such that they define a tilt angle and a rotation angle with respect to the longitudinal axes of the object being scanned. Successive slices have equal tilt angles but changing rotation angles such that normal axes of successive slices define a nutation and precession about the longitudinal axis of the object. Projection data for the tilted slices are formed of selected one-dimensional fan-beam data. As such, the projection data can be applied to conventional two-dimensional reconstruction approaches to generate an image. The projection data can also be used to generate two-dimensional projection images at one or more stationary projection angles through an object being scanned. The nutation or tilt of image volume elements can be compensated for to provide a more accurate image and more accurate target assessment such as accurate total mass determination. A parallel processing architecture can be used to generate and process the nutated slices with improved efficiency.
Inventors
- 👤 Carl R. Crawford
- 👤 Christopher C. Ruth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:25
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/027; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
122 words
A method of processing computed tomography scan data for a region having a longitudinal axis, said method comprising: scanning the region with a radiation source and an array of detectors to generate the scan data for the region; defining a plurality of image data slices corresponding to a plurality of positions along the longitudinal axis of the region, successive image data slices being non-parallel with each other and each image data slice defining a plurality of image volume elements tilted with respect to the longitudinal axis, each image volume element being associated with an image density value; and applying a correction factor to the image density values of the tilted volume elements to compensate for the tilt of the image volume elements.
Claim 2
Independent Claim
122 words
A method of processing computed tomography scan data for a region having a longitudinal axis, said method comprising: scanning the region with a radiation source and an array of detectors to generate the scan data for the region; defining a plurality of image data slices corresponding to a plurality of positions along the longitudinal axis of the region, successive image data slices being non-parallel with each other and each image data slice defining a plurality of image volume elements tilted with respect to the longitudinal axis, each image volume element being associated with an image density value; and applying a correction factor to the image density values of the tilted volume elements to compensate for the tilt of the image volume elements.
Claim 3
Dependent Claim
22 words
The method of claim 1 further comprising processing the image density values to determine a mass of an object in the region.
Claim 4
Dependent Claim
31 words
The method of claim 2 wherein processing the image density values to determine a mass of an object in the region comprises applying a density threshold to the image density values.
Claim 5
Dependent Claim
42 words
The method of claim 3 wherein: density values which exceed the density threshold are used to determine the mass of the object; and density values which do not exceed the density threshold are not used to determine the mass of the object.
Claim 6
Dependent Claim
22 words
The method of claim 3 wherein image density values that exceed the threshold are considered to be associated with an explosive material.
Claim 7
Dependent Claim
12 words
The method of claim 2 where the object comprises an explosive material.
Claim 8
Dependent Claim
44 words
The method of claim 1 wherein scanning the region further comprises translating the radiation source and the array of detectors along the longitudinal axis of the region while rotating the radiation source and the array of detectors about the longitudinal axis of the region.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the radiation source is a cone-beam source.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein successive image data slices are nutated with respect to each other.
Claim 11
Dependent Claim
14 words
The method of claim 1 wherein the array of detectors is a two-dimensional array.
Claim 12
Dependent Claim
15 words
The method of claim 1 wherein the scan data is generated using a helical scan.
Claim 13
Dependent Claim
16 words
The method of claim 1 wherein the scan data is generated using a helical cone-beam scan.
Claim 14
Independent Claim
126 words
An apparatus for processing computed tomography scan data for a region having a longitudinal axis, said apparatus comprising: an array of detectors for scanning the region to generate the scan data for the region; a processor for defining a plurality of image data slices corresponding to a plurality of positions along the longitudinal axis of the region such that successive image data slices are non-parallel with each other and each image data slice defines a plurality of image volume elements tilted with respect to the longitudinal axis and each image volume element is associated with an image density value; and means for applying a correction factor to the image density values of the tilted volume elements to compensate for the tilt of the image volume element.
Claim 15
Independent Claim
126 words
An apparatus for processing computed tomography scan data for a region having a longitudinal axis, said apparatus comprising: an array of detectors for scanning the region to generate the scan data for the region; a processor for defining a plurality of image data slices corresponding to a plurality of positions along the longitudinal axis of the region such that successive image data slices are non-parallel with each other and each image data slice defines a plurality of image volume elements tilted with respect to the longitudinal axis and each image volume element is associated with an image density value; and means for applying a correction factor to the image density values of the tilted volume elements to compensate for the tilt of the image volume element.
Claim 16
Dependent Claim
24 words
The apparatus of claim 13 further comprising means for processing the image density values to determine a mass of an object in the region.
Claim 17
Dependent Claim
36 words
The apparatus of claim 14 wherein the means for processing the image density values to determine a mass of an object in the region comprises means for applying a density threshold to the image density values.
Claim 18
Dependent Claim
42 words
The apparatus of claim 15 wherein: density values which exceed the density threshold are used to determine the mass of the object; and density values which do not exceed the density threshold are not used to determine the mass of the object.
Claim 19
Dependent Claim
22 words
The apparatus of claim 15 wherein image density values that exceed the threshold are considered to be associated with an explosive material.
Claim 20
Dependent Claim
12 words
The apparatus of claim 14 wherein the object comprises an explosive material.
Claim 21
Dependent Claim
43 words
The apparatus of claim 13 further comprising means for translating the radiation source and the array of detectors along the longitudinal axis of the region while the radiation source and the array of detectors are rotated about the longitudinal axis of the region.
Claim 22
Dependent Claim
13 words
The apparatus of claim 13 wherein the radiation source is a cone-beam source.
Claim 23
Dependent Claim
14 words
The apparatus of claim 13 wherein the array of detectors is a two-dimensional array.
Claim 24
Dependent Claim
20 words
The apparatus of claim 13 wherein the array of detectors is adapted to perform a helical scan of the region.
Claim 25
Dependent Claim
21 words
The apparatus of claim 13 wherein the array of detectors is adapted to perform a helical cone-beam scan of the region.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-31 | 2002-11-30 | 2003-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-31 | 2006-11-30 | 2007-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-31 | 2010-11-30 | 2011-06-01 | $7700.00 | Window Closed / Lapsed |