A New Modeling Method on Skull Defect Repair.pdf

A New Modeling Method on Skull Defect Repair Fei You, Qingxi Hu, Yuan Yao, and Qi Lu Rapid Manufacturing Engineering Center Shanghai University Shanghai, China yfreeman@ Abstract—To obtain the fairing surface model of the loss part of detective skull rapidly, a new modeling method on skull defect repair is proposed in this paper. This method is to adopt the surface reconstruction algorithm to construct the local model of defective skull based on the sub-pixel cube model. The hole’s feature on the surface is automatically identified by adopting the dihedral angle criteria algorithm, and two three- dimensional polygons are generated by searching the boundary edge of the hole. The polygon is triangulated based on the minimum area principle, and the mesh is refined based on the shortest edge principle. The weighted umbrella-operator is applied to control the curvature transformation of the patching mesh for smoothing it, and the fairing surface patch is generated. Then, the prosthesis model of defective skull is generated by Boolean calculation between every two key models. The modeling efficiency and precision are too higher. Keywords- skull defect repair; sub-pixel cube; reconstruction; mesh refinement and fairing; prosthesis model I. INTRODUCTION The traditional method needs two operations to repair the defective skull. With the development of the medical image processing and RP (Rapid Prototyping) technology, both are integrated to repair defective skull to relieve the injury of patients because of two operations. The first step is to obtain CT image of skull by using section scan, and to reconstruct its 3D (three-dimensional) model by adopting medical image processing system. Then, the prosthesis of defective skull is manufactured by using RP technology. Lastly, the prosthesis is implanted into the defective position [1,2,3]. So, 3D modeling of skull defect repair becomes the key technology of this field, and the research