Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
Figure 9.
(b) Merge through the user interaction method. (c)Partial
result. (d) Solution after manual cut.
(a) Original objects.
with the following parameters: grid 5
×
5
×
5, freezing point = 10,
γ
=0
.
01,
k
=1
.
222;
c
=0
.
750. Each sphere has radius 30 (pixels). In this case, the merge
is forced through an implicit defined surface placed between the spheres (Figure
9a). Grid nodes inside the surface are easily detected by the surface equation and
then burnt. During the evolution, all the four surfaces will merge and the final
result is a connected surface (Figure 9b).
Another possibility would be to manually burn a set of grid nodes linking the
spheres. The idea in this case is that the new set of burnt grid nodes generates a
connected combinatorial manifold.
Let us demonstrate the manual split. Figure 9c shows an example where steps
(1)-(6) were not able to complete the segmentation. The 3D image is composed
by 2 ellipsoids of radius 30, 45, and 60 and a sphere of radius 30, immersed in a
150
×
150
×
150 noise volume.
