Scan-Conversion Algorithm for Ridge Point Detection on Tubular Objects

Abstract

Abstract. Anatomical structures contain various types of curvilinear or tube-like structures such as blood vessels and bronchial trees. In medical imaging, the extraction and representation of such structures are of clinical importance. Complex curvilinear structures can be best represented by their center lines (or skeletons) along their elongated direction. In this paper, a gradient-based method for ridge point extraction on tubular objects is presented. Using the gradients of distance maps or intensity profiles usually generates skeleton surfaces for 3D objects, which is not desirable for representing tubular objects. To extract only the points on the centerline, we first employ the gradient vector flow (GVF) technique and then apply eigenanalysis of the Hessian matrix to remove false positive points. We present various results of the method using CLSM (Confocal Laser Scanning Microscopy) images of blood fibrins and CT images of a skull and lungs. Our method is efficient and allows for completely automatic extraction of points along the centerline of a tubular object in its elongated direction.

Differential Fly-Throughs (DFT): A General Framework for Computing Flight Paths

“…In [14], Xu has shown that the GVF possesses as well some medial properties by suggesting two different medialness functions based on the magnitude of the GVF, to measure only how close a point from the skeleton of a 2D shape, rather than computing the skeleton itself. One of the interesting properties of the GVF, V (x) over the distance field D(x) is that it does not form medial surfaces for non-tubular 3D objects [15] because only one boundary voxel contributes to the computation of D(x), while more than one boundary voxels contribute to the computation of V (x) during the diffusion process.…”