Region filling and hole repair of bio-medical models

Abstract

In this paper, a model repair technique is introduced mainly to handle defective bio-models with triangular surface meshes or in stereo-lithography format [14]. This technique can help in the design of custom implants for "empty regions" on bio-parts with no underlying surfaces. It can subsequently be extended to allow assessment of defects and implants preoperatively, and improve fixation. An element based hole-filling algorithm is developed to fill any complex holes in oriented connected manifold meshes and to ensure water-tightness due to missing surface patches in both 3D surface models and faceted models. We specifically address situations in which the holes are too geometrically and topologically complex to fill using normal triangulation algorithms, and describe a method for filling holes in unstructured triangular meshes. The resulting patching meshes interpolate the shape and density of the surrounding mesh, The steps in filling a hole include boundary identification, two stage hole triangulations using Genetic Algorithm and advancing front technique, and surface approximation based on a Quartic Gregory patch.