Method and apparatus for registration of virtual endoscopic images
First Claim
1. A method for registration of virtual endoscopic images, said method comprising:
- deriving first and second volumetric images by an endoscopic protocol and representing said images by respective first and second volumetric image data sets;
deriving respective centerline representations by connected line components;
resampling said connected components to provide respective first and second sample sets;
computing a descriptor for each sample;
computing a similarity matrix using distances between said descriptors; and
determining an optimal set of point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix.
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Abstract
A method for registration of virtual endoscopy images in first and second patient positions comprises performing colon segmentation and feature extraction, including centerline and colon surface data for each of the images; resampling the centerline and colon surface data; computing respective local descriptors; pairing point correspondences on the centerlines between the first and second images by minimal cost matching; extrapolating the centerline point correspondences to a 3-dimensional/3-dimensional (3D/3D) transformation between the first and second images. The method also includes selecting a position for a virtual endoscope in one of the images; associating an orthogonal reference frame with the virtual endoscope; and applying the 3D/3D transformation to the orthogonal reference frame so as to derive a corresponding transformed reference frame for the virtual endoscope in the other of the images.
53 Citations
47 Claims
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1. A method for registration of virtual endoscopic images, said method comprising:
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deriving first and second volumetric images by an endoscopic protocol and representing said images by respective first and second volumetric image data sets;
deriving respective centerline representations by connected line components;
resampling said connected components to provide respective first and second sample sets;
computing a descriptor for each sample;
computing a similarity matrix using distances between said descriptors; and
determining an optimal set of point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix. - View Dependent Claims (2, 3, 4)
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5. A method for prone-supine registration of first and second volumetric images obtained by virtual colonoscopy and including respective centerline representations by connected polygonal line components and including respective colon radius information, said method comprising:
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resampling of said connected components to provide respective first and second centerline sample sets;
computing a descriptor for each sample;
computing a similarity matrix using distances between said descriptors;
determining an optimal set of centerline point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix;
extrapolating said centerline point correspondences to a 3-dimensional/3-dimensional (3D/3D) transformation between said first and second volumetric images; and
applying said 3D/3D transformation to transform a virtual endoscope position between said first and second volumetric images.
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6. A method for prone-supine registration of first and second volumetric images obtained by virtual colonoscopy represent by respective first and second volumetric datasets, including respective centerline representations by connected polygonal lines and including colon radius information, said method comprising:
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resampling of said connected polygonal lines to provide respective first and second sample sets;
computing a descriptor for each sample;
computing a similarity matrix using distances between said descriptors; and
determining an optimal set of point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix. - View Dependent Claims (7, 8)
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9. A method for registration of virtual endoscopy images in first and second patient positions, said method comprising:
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performing colon segmentation and feature extraction, including centerline and colon surface data for each of said images;
resampling said centerline and colon surface data;
computing respective local descriptors;
pairing point correspondences on said centerlines between said first and second images by minimal cost matching; and
extrapolating said centerline point correspondences to a 3-dimensional/3-dimensional (3D/3D) transformation between said first and second images. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for prone-supine registration of first and second volumetric images, obtained by virtual colonoscopy and represented by first and second volumetric image data sets, including respective centerline representations by connected polygonal line components, and including respective colon radius data, said method comprising:
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resampling of said connected line components to provide respective first and second sample sets;
computing, for each sample, a descriptor comprising a vector of geometric features and an estimated value of said colon radius data;
computing a similarity matrix using distances between said descriptors;
applying a minimization procedure to said similarity matrix to determine an optimal set of correspondences between points of said first and second sample sets by applying an algorithm to said similarity matrix for minimizing the sum of distances between all corresponding points;
extrapolating said centerline point correspondences to a 3-dimensional/3-dimensional (3D/3D) transformation between said first and second volumetric images;
selecting a position for a virtual endoscope in one of said volumetric images;
associating an orthogonal reference frame with said virtual endoscope; and
applying said 3D/3D transformation to said orthogonal reference frame so as to derive a corresponding transformed reference frame for said virtual endoscope in the other of said volumetric images. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method for registration of virtual endoscopic images, said method comprising:
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deriving first and second volumetric images by a colonoscopy protocol and representing said images by respective first and second volumetric image data sets;
deriving respective centerline representations by connected polygonal line components;
identifying a colon surface in each of said volumetric images;
deriving respective colon radius information by determining the distance from each point of said centerline representation to a respectively closest point on said colon surface;
resampling said connected components to provide respective first and second sample sets;
computing a descriptor for each sample;
computing a similarity matrix using distances between said descriptors; and
determining an optimal set of point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix. - View Dependent Claims (44, 45)
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46. Apparatus for prone-supine registration of first and second volumetric images obtained by virtual colonoscopy and including respective centerline representations by connected polygonal line components and including respective colon radius information, said apparatus comprising:
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means for resampling of said connected components to provide respective first and second centerline sample sets;
means for computing a descriptor for each sample;
means for computing a similarity matrix using distances between said descriptors;
means for determining an optimal set of centerline point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix;
means for extrapolating said centerline point correspondences to a 3-dimensional/3-dimensional (3D/3D) transformation between said first and second volumetric images; and
means for applying said 3D/3D transformation to transform a virtual endoscope position between said first and second volumetric images.
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47. Apparatus for registration of virtual endoscopic images, said apparatus comprising:
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means for deriving first and second volumetric images by an endoscopic protocol and representing said images by respective first and second volumetric image data sets;
means for deriving respective centerline representations by connected line components;
means for resampling said connected components to provide respective first and second sample sets;
means for computing a descriptor for each sample;
means for computing a similarity matrix using distances between said descriptors; and
means for determining an optimal set of point correspondences between said first and second sample sets by application of a minimization algorithm to said similarity matrix.
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Specification