Patent US5799099A successfully refreshed from Google Patents.
US5799099A
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Automatic technique for localizing externally attached fiducial markers in volume images of the head
Assignee: Marker LLC
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Filing: 1995-06-06
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Granted: 1998-08-25
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Expires: 2015-06-06
Abstract
Abstract An automatic computer implemented technique which may be used for identifying markers and determining the centroids of fiducial markers (e.g., cylindrical fiducial markers) attached to the head in magnetic resonance (MR) and X-ray computed tomography (CT) volume images is disclosed. This technique may be referred to as image space localization. A first portion of the technique identifies many candidate voxel points included in a bright area of the image which may correspond to candidate markers. A second portion of the technique selects from the identified candidate voxels a predetermined number of candidate points of the image volume that are most likely to lie within an actual fiducial marker. The centroid for each of these markers is then determined. The method finds markers whose images are of a higher intensity than their surroundings and which have a given shape and size.
Inventors
- 👤 Matthew Y. Wang
- 👤 Calvin R. Maurer, Jr.
- 👤 J. Michael Fitzpatrick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:58
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; A; A61; A61B; A61B6/00; A61B6/12; A61B90/00; A61B90/36; A61B90/39; G06; G06T; G06T7/00; G06T7/0002; G06T7/0012; G06T7/10; G06T7/155; G06T7/194; G06T7/30; G06T7/33; G06T7/60; G06T7/66; G06T7/70; G06T7/73; G06V; G06V10/00; G06V10/20; G06V10/25; A61B2090/363; A61B2090/3904; A61B2090/3916; A61B2090/3987; G06T2207/00; G06T2207/10; G06T2207/10072; G06T2207/10081; G06T2207/10088; G06T2207/30; G06T2207/30004; G06T2207/30016; G06T2207/30204
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
227 words
A method for automatically localizing a predetermined number M of fiducial markers in at least one image volume, comprising steps of: searching the at least one image volume for candidate markers, said markers including a number of three-dimensional connected voxels having similar intensities and being within a predetermined size range; representing each of said candidate markers by a candidate voxel containing the centroid of the candidate marker; and examining a three-dimensional region in the at least one image volume around each of the candidate voxels and determining which of said candidate markers represented by said candidate voxels most likely correspond to said fiducial markers in said at least one image volume, and including for each of said candidate voxels: determining whether a size and shape of a set of foreground voxels connected to said candidate voxel is similar to a foreground component of a fiducial marker; discarding the candidate voxel if the size and shape are not determined to be similar; determining a centroid of the set of foreground voxels; repeating said determining steps until a same centroid has been determined twice in succession; discarding the candidate voxel if the determining steps are implemented a predetermined number of times; and if a same centroid has been determined twice in succession, recording said same centroid as a final centroid and recording a corresponding intensity of said final centroid.
Claim 2
Independent Claim
227 words
A method for automatically localizing a predetermined number M of fiducial markers in at least one image volume, comprising steps of: searching the at least one image volume for candidate markers, said markers including a number of three-dimensional connected voxels having similar intensities and being within a predetermined size range; representing each of said candidate markers by a candidate voxel containing the centroid of the candidate marker; and examining a three-dimensional region in the at least one image volume around each of the candidate voxels and determining which of said candidate markers represented by said candidate voxels most likely correspond to said fiducial markers in said at least one image volume, and including for each of said candidate voxels: determining whether a size and shape of a set of foreground voxels connected to said candidate voxel is similar to a foreground component of a fiducial marker; discarding the candidate voxel if the size and shape are not determined to be similar; determining a centroid of the set of foreground voxels; repeating said determining steps until a same centroid has been determined twice in succession; discarding the candidate voxel if the determining steps are implemented a predetermined number of times; and if a same centroid has been determined twice in succession, recording said same centroid as a final centroid and recording a corresponding intensity of said final centroid.
Claim 3
Dependent Claim
13 words
The method of claim 1, wherein said predetermined number of times is three.
Claim 4
Dependent Claim
27 words
The method of claim 1, further comprising a step of ranking the recorded final centroids of each of said candidate voxels according to their corresponding recorded intensities.
Claim 5
Independent Claim
342 words
A method for automatically localizing three-dimensional centroids of a predetermined number M of fiducial markers in at least one image volume, comprising steps of: searching the at least one image volume for candidate markers, said candidate markers including a number of three-dimensional connected voxels having similar intensities and being within a predetermined size range and representing each of said candidate markers by a candidate voxel containing the centroid of the candidate marker, including: applying a median filter within each of a plurality of slices of the at least one image volume; forming a new smaller image volume for each slice by subsampling; determining an intensity threshold value; producing a binary image from said new smaller image of foreground and background voxels in response to said intensity threshold value; filling in any holes in the binary image; removing small components and small protrusions on large components appearing in the binary image; selecting components in the removed binary image which are most similar to a fiducial marker, said number of components being larger than said predetermined number M; and providing said selected components as the candidate voxels; examining a three-dimensional region in the at least one image volume around each of the candidate voxels and determining which of said candidate markers represented by said candidate voxels most likely correspond to said fiducial markers in said at least one image volume including for each of said candidate voxels: determining whether a size and shape of a set of foreground voxels connected to said candidate voxel is similar to a foreground component of a marker; discarding the candidate voxel if the size and shape are not determined to be similar; determining a centroid of the set of foreground voxels; repeating said determining steps until a same centroid has been determined twice in succession; discarding the candidate voxel if the determining steps are implemented a predetermined number of times; and if a same centroid has been determined twice in succession, recording said same centroid as a final centroid and recording a corresponding intensity of said final centroid.
Claim 6
Independent Claim
342 words
A method for automatically localizing three-dimensional centroids of a predetermined number M of fiducial markers in at least one image volume, comprising steps of: searching the at least one image volume for candidate markers, said candidate markers including a number of three-dimensional connected voxels having similar intensities and being within a predetermined size range and representing each of said candidate markers by a candidate voxel containing the centroid of the candidate marker, including: applying a median filter within each of a plurality of slices of the at least one image volume; forming a new smaller image volume for each slice by subsampling; determining an intensity threshold value; producing a binary image from said new smaller image of foreground and background voxels in response to said intensity threshold value; filling in any holes in the binary image; removing small components and small protrusions on large components appearing in the binary image; selecting components in the removed binary image which are most similar to a fiducial marker, said number of components being larger than said predetermined number M; and providing said selected components as the candidate voxels; examining a three-dimensional region in the at least one image volume around each of the candidate voxels and determining which of said candidate markers represented by said candidate voxels most likely correspond to said fiducial markers in said at least one image volume including for each of said candidate voxels: determining whether a size and shape of a set of foreground voxels connected to said candidate voxel is similar to a foreground component of a marker; discarding the candidate voxel if the size and shape are not determined to be similar; determining a centroid of the set of foreground voxels; repeating said determining steps until a same centroid has been determined twice in succession; discarding the candidate voxel if the determining steps are implemented a predetermined number of times; and if a same centroid has been determined twice in succession, recording said same centroid as a final centroid and recording a corresponding intensity of said final centroid.
Claim 7
Dependent Claim
13 words
The method of claim 4, wherein said predetermined number of times is three.
Claim 8
Dependent Claim
27 words
The method of claim 4, further comprising a step of ranking the recorded final centroids of each of said candidate voxels according to their corresponding recorded intensities.
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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) | 2001-08-24 | 2002-02-23 | 2002-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-24 | 2006-02-23 | 2006-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-24 | 2010-02-23 | 2010-08-25 | $7700.00 | Window Closed / Lapsed |