System and method for performing a virtual endoscopy in a branching structure

1 . A method for performing a virtual endoscopy in a branching structure, comprising:

determining an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

casting a plurality of rays from the initial viewpoint along the viewing direction; and

determining an occurrence of a branch in the branching structure, wherein the occurrence is associated with a cluster that corresponds to the branch.

2 . The method of claim 1 , further comprising:

acquiring three-dimensional (3D) data of the branching structure.

3 . The method of claim 2 , wherein the 3D data is acquired by one of a computed tomographic (CT), helical CT, x-ray, positron emission tomographic, fluoroscopic, ultrasound, and magnetic resonance (MR) imaging technique.

4 . The method of claim 1 , further comprising:

rendering 3D data of the branching structure.

5 . The method of claim 4 , wherein the rendering is performed using one of a raycasting, splatting, shear-warping, texture mapping, surface rendering, and volume rendering technique.

6 . The method of claim 1 , wherein the branching structure is one of a bronchial tree, blood vessel, airway, sinus, and heart.

7 . The method of claim 1 , wherein the initial viewpoint and viewing direction are selected by a user.

8 . The method of claim 1 , wherein the cluster is formed by performing a thresholding of a length of the plurality of rays followed by a computation of connected components.

9 . The method of claim 1 , wherein the cluster is formed by one of a k-means clustering, and mean-shift based clustering of the plurality of rays.

10 . The method of claim 1 , wherein the cluster is formed by constructing a minimum spanning tree (MST) of endpoints of the plurality of rays and thresholding of an edge length of edges in the MST to separate the endpoints of the plurality of rays.

11 . The method of claim 1 , wherein the cluster is formed by projecting endpoints of the plurality of rays onto a viewing plane of the virtual endoscope in parallel to form a two-dimensional (2D) image of the endpoints and performing one of a thresholding of a length of the plurality of rays followed by a computation of connected components, k-means clustering, and mean-shift based clustering.

12 . The method of claim 1 , further comprising:

determining a direction to navigate the virtual endoscope by selecting the branch.

13 . The method of claim 12 , wherein the selected branch is determined by extracting a longest ray from the cluster.

14 . The method of claim 12 , further comprising:

navigating the virtual endoscope from the viewpoint to the selected branch.

15 . The method of claim 14 , wherein the navigation is one of a “top-down” and “bottom-up” type navigation.

16 . The method of claim 1 , further comprising:

storing the occurrence of the branch.

17 . A method for performing a virtual endoscopy in a branching structure, comprising:

determining an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

selecting a preferred direction of the virtual endoscope;

casting a plurality of rays from the initial viewpoint;

determining a longest ray from the initial viewpoint using the preferred direction as a weight; and

navigating through the branching structure to the preferred direction.

18 . The method of claim 17 , further comprising:

acquiring three-dimensional (3D) data of the branching structure.

19 . The method of claim 18 , wherein the 3D data is acquired by one of a computed tomographic (CT), helical CT, x-ray, positron emission tomographic, fluoroscopic, ultrasound, and magnetic resonance (MR) imaging technique.

20 . The method of claim 17 , further comprising:

rendering 3D data of the branching structure.

21 . The method of claim 20 , wherein the rendering is performed using one of a raycasting, splatting, shear-warping, texture mapping, surface rendering, and volume rendering technique.

22 . The method of claim 17 , wherein the branching structure is one of a bronchial tree, blood vessel, airway, sinus, and heart.

23 . The method of claim 17 , wherein the preferred direction is selected by a user.

24 . The method of claim 17 , wherein the weight is determined by calculating an inner product of the preferred direction and each of the plurality of rays.

25 . A system for performing a virtual endoscopy in a branching structure, comprising:

a memory device for storing a program;

a processor in communication with the memory device, the processor operative with the program to:

determine an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

cast a plurality of rays from the initial viewpoint along the viewing direction using a raycasting technique; and

determine a location of a branch in the branching structure, wherein the location is associated with a cluster that corresponds to the branch.

26 . The system of claim 25 , wherein the processor is further operative with the program code to:

render 3D data of the branching structure.

27 . The system of claim 25 , wherein the cluster is formed by performing a thresholding of a length of the plurality of rays followed by a computation of connected components.

28 . A system for performing a virtual endoscopy in a branching structure, comprising:

a memory device for storing a program;

a processor in communication with the memory device, the processor operative with the program to:

determine an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

select a preferred direction of the virtual endoscope;

cast a plurality of rays from the initial viewpoint using a raycasting technique;

determine a longest ray from the initial viewpoint using the preferred direction as a weight; and

navigate through the branching structure to the preferred direction.

29 . The system of claim 28 , wherein the weight is determined by calculating an inner product of the preferred direction and each of the plurality of rays.

30 . A computer program product comprising a computer useable medium having computer program logic recorded thereon for performing a virtual endoscopy, the computer program logic comprising:

program code for determining an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

program code for casting a plurality of rays from the initial viewpoint along the viewing direction; and

program code for determining an occurrence of a branch in the branching structure, wherein the occurrence is associated with a cluster that corresponds to the branch.

31 . A computer program product comprising a computer useable medium having computer program logic recorded thereon for performing a virtual endoscopy, the computer program logic comprising:

program code for determining an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

program code for selecting a preferred direction of the virtual endoscope;

program code for casting a plurality of rays from the initial viewpoint;

program code for determining a longest ray from the initial viewpoint using the preferred direction as a weight, wherein the weight is determined by calculating an inner product of the preferred direction and each of the plurality of rays; and

program code for navigating through the branching structure to the preferred direction.

32 . A system for performing a virtual endoscopy in a branching structure, comprising:

means for determining an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

means for casting a plurality of rays from the initial viewpoint along the viewing direction; and

means for determining an occurrence of a branch in the branching structure, wherein the occurrence is associated with a cluster that corresponds to the branch.

33 . A system for performing a virtual endoscopy in a branching structure, comprising:

means for determining an initial viewpoint and viewing direction of a virtual endoscope in a branching structure;

means for selecting a preferred direction of the virtual endoscope;

means for casting a plurality of rays from the initial viewpoint;

means for determining a longest ray from the initial viewpoint using the preferred direction as a weight; and

means for navigating through the branching structure to the preferred direction.