This paper presents a novel algorithm for identifying quadric surfaces from scanned mechanical models. We make several important improvements over the existing variational 3D shape segmentation framework, which utiliz...This paper presents a novel algorithm for identifying quadric surfaces from scanned mechanical models. We make several important improvements over the existing variational 3D shape segmentation framework, which utilizes Lloyd＇s iteration. First, instead of using randomized initialization （which likely falls into non-optimal minimum）, the RANSAC-based initialization approach is adopted. Given a good initialization, our method converges quickly than previous approaches. Second, in order to enhance the stability and the robustness, we carefully modify the distortion-minimizing flooding algorithm by using seed regions instead of seed triangles. Third, the geometric constraints are introduced into the optimization framework. The segmentation quality is further improved. We validate the efficiency and the robustness of our proposed method on various datasets, and demonstrate that our method outperforms state-of-art approaches.展开更多
A method for representing quadric surfaces using NURBS is presented. By means of the necessary and sufficient conditions for NURBS cu-rves to precisely represent circular arcs and other conics, quadric surfaces can be...A method for representing quadric surfaces using NURBS is presented. By means of the necessary and sufficient conditions for NURBS cu-rves to precisely represent circular arcs and other conics, quadric surfaces can be represented by NURBS surfaces with fewer control vertices. The method can be used not only for NURBS surface representation of quadric surfaces, but also for rounding polyhedrons. Many examples are given in the paper.展开更多
基金Supported by the National Natural Science Foundation of China(61372168,61620106003 and 61331018)
文摘This paper presents a novel algorithm for identifying quadric surfaces from scanned mechanical models. We make several important improvements over the existing variational 3D shape segmentation framework, which utilizes Lloyd＇s iteration. First, instead of using randomized initialization （which likely falls into non-optimal minimum）, the RANSAC-based initialization approach is adopted. Given a good initialization, our method converges quickly than previous approaches. Second, in order to enhance the stability and the robustness, we carefully modify the distortion-minimizing flooding algorithm by using seed regions instead of seed triangles. Third, the geometric constraints are introduced into the optimization framework. The segmentation quality is further improved. We validate the efficiency and the robustness of our proposed method on various datasets, and demonstrate that our method outperforms state-of-art approaches.
文摘A method for representing quadric surfaces using NURBS is presented. By means of the necessary and sufficient conditions for NURBS cu-rves to precisely represent circular arcs and other conics, quadric surfaces can be represented by NURBS surfaces with fewer control vertices. The method can be used not only for NURBS surface representation of quadric surfaces, but also for rounding polyhedrons. Many examples are given in the paper.
