While level sets have demonstrated a great potential for 3D medical image
segmentation, their usefulness has been limited by two problems. First, 3D
level sets are relatively slow to compute. Second, their formulation usually
entails several free parameters which can be very difficult to correctly tune
for specific applications. The second problem is compounded by the first.
This paper describes a new tool for 3D segmentation that addresses these
problems by computing level-set surface models at interactive rates. This tool
employs two important, novel technologies. First is the mapping of a 3D
level-set solver onto a commodity graphics card (GPU). This mapping relies on
a novel mechanism for GPU memory management. The interactive rates level-set
PDE solver give the user immediate feedback on the parameter settings, and thus
users can tune free parameters and control the shape of the model in real time.
The second technology is the use of intensity-based speed functions, which
allow a user to quickly and intuitively specify the behavior of the deformable
model. We have found that the combination of these interactive tools enables
users to produce good, reliable segmentations. To support this observation,
this paper presents qualitative results from several different datasets as well
as a quantitative evaluation from a study of brain tumor segmentations.