Patent ID: 11961187
Assignee: OXFORD UNIVERSITY INNOVATION LIMITED
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 14:
15. The method as claimed in claim 1, which additionally comprises the Steps:
(F) back-projecting the resultant compound curve representing the 3D centerline of the organ vessel onto the first and second 2D images;
(G) comparing segments of the back-projected compound curve to the corresponding segments of the 2D centerlines in the first and second images by determining the degree of point-to-point correspondences between a plurality of points on each of the segments of the back-projected compound curve and the corresponding points on the segments of the 2D centerlines in the first and second images;
(H) generating a further point-cloud of 3D points which comprises:
(i) for segments with high degrees of point-to-point correspondences between the plurality of points on the segments of the back-projected compound curve and the corresponding points on the segments of the 2D centerlines in the first and second images,
a first set of points which represent the intersection points between
(a) projection lines from the plurality of points on those segments in the first 2D image to the first x-ray source, and
(b) projection lines from the corresponding points on the corresponding segments in the second 2D image to the second x-ray source; and

(ii) for segments with low degrees of point-to-point correspondences between the plurality of points on the segments of the back-projected compound curve and the corresponding points on the segments of the 2D centerlines in the first and second images,
a second set of points which represent the intersection points between
(a) projection lines from the plurality of points on those segments in the first 2D image to the first x-ray source, and
(b) projection lines from the plurality of points on the corresponding segments in the second 2D image to the second x-ray source;

a third set of points which represent the nearest orthogonal points between projection lines defined in (a) and (b) if the projection lines defined in (a) and (b) do not intersect;

(I) fitting a compound curve to the points in the further point-cloud of 3D points, the compound curve having a defined number of breakpoints;
(J) removing outliers from the point-cloud of 3D points;
(K) fitting a new compound curve to the remaining points in the point-cloud of 3D points, the new compound curve having an increased number of breakpoints compared to the previous compound curve; and
(L) repeating Steps (J) and (K) one or more times;
wherein the resultant compound curve represents the 3D centerline of the organ vessel.