Method and apparatus for correlating a body with an image of the body
First Claim
1. A process for identifying points on a spatial body which correspond to points on a data-base body comprising previously acquired images of the spatial body, comprising the steps of:
- (a) selecting at least four data-base points on the data-base body;
(b) determining relative positional information between the data-base points;
(c) selecting at least four spatial points on the spatial body;
(d) determining relative positional information between the spatial points;
(e) matching a first spatial point to a corresponding data-base points by determining which of the spatial points have relative positional information which correspond to the relative positional information between the data-base points; and
(f) testing the first matched spatial point to determine if the first matched spatial point is a symmetric false match of the corresponding data-base point.
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Abstract
The present invention provides a system and process for correlating points on a spatial body to corresponding points on a data-base body formed from pre-acquired images of the spatial body. The system and process involves matching the spatial points with the corresponding data-base points using relative positional information between the spatial points and the data-base points. Symmetric false matches are detected and discarded by fitting the spatial points and data-base points to a first and second closed body, respectively, and comparing the orientation of the spatial points and the data-base points projected onto the closed bodies. In a preferred embodiment, the orientations of the spatial points and data-base points are compared by calculating, with respect to a matched spatial point, the longitudinal coordinates of the spatial points neighbouring the matched spatial point and calculating, with respect to the matched data-base point, the longitudinal co-ordinates of the data-base points neighbouring the matched data-base point, and comparing the difference in longitude between the points. If the difference in longitude of the spatial points corresponds to the difference in longitude of the data-base points, the match of the matched spatial point to the matched data-base point will be validated. Otherwise, the match will be considered a symmetric false match and discarded. Once at least three spatial points have been matched to corresponding data-base points, and the matches have been confirmed not to be false matches, a registration procedure is performed registering the spatial body to the data-base body by calculating a transformation mapping using the three matched pairs.
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Citations
21 Claims
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1. A process for identifying points on a spatial body which correspond to points on a data-base body comprising previously acquired images of the spatial body, comprising the steps of:
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(a) selecting at least four data-base points on the data-base body; (b) determining relative positional information between the data-base points; (c) selecting at least four spatial points on the spatial body; (d) determining relative positional information between the spatial points; (e) matching a first spatial point to a corresponding data-base points by determining which of the spatial points have relative positional information which correspond to the relative positional information between the data-base points; and (f) testing the first matched spatial point to determine if the first matched spatial point is a symmetric false match of the corresponding data-base point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for visualizing internal regions of an anatomical body in relation to a probe employing a data-base body of previously acquired images of the anatomical body, the method comprising the steps of:
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(a) selecting at least four data-base points on the data-base body; (b) determining relative positional information between the data-base points; (c) selecting at least four spatial points on the anatomical body; (d) determining relative positional information between the spatial points; (e) matching at least three of the spatial points to corresponding data-base points by determining which of the spatial points have relative positional information with respect to each other spatial point which correspond to the relative positional information between the data-base points; (f) fitting the data-base points to a first closed body having a regular shape and a first surface such that the data-base points are projected onto the first surface in a first orientation; (g) fitting the spatial points to a second closed body having the same shape as the first closed body and a second surface such that the spatial points are projected onto the second surface in a second orientation; (h) for each matched spatial point, comparing the matched spatial point with its corresponding data-base point to determine if the matched spatial point is a symmetric false match of the corresponding data-base point by comparing the orientation of the spatial points with respect to the matched spatial point on the second surface to the orientation of the data-base points with respect to the corresponding data-base point on the first surface, wherein the matched spatial point is not a symmetric false match of the corresponding data-base point if the orientation of the spatial points on the second surface corresponds to the orientation of the data-base points on the first surface; and (i) registering the spatial body to the data-base body based on at least three matched spatial points and the corresponding data-base points which have been determined not to be symmetric false matches. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification