Subvoxel precise skeletons of volumetric data based on fast marching methods.

The accurate calculation of the skeleton of an object is a problem not satisfactorily solved by existing approaches. Most algorithms require a significant amount of user interaction and use a voxel grid to compute discrete and often coarse approximations of this representation of the data. We present a novel, automatic algorithm for computing subvoxel precise skeletons of volumetric data based on subvoxel precise distance fields. Most voxel based centerline and skeleton algorithms start with a binary mask and end with a list of voxels that define the centerline or skeleton. Even though subsequent smoothing may be applied, the results are inherently discrete. Our skeletonization algorithm uses as input a subvoxel precise distance field and employs a number of fast marching method propagations to extract the skeleton at subvoxel precision. We present the skeletons of various three-dimensional (3D) data sets and digital phantom models as validations of our algorithm.