摘要
牙齿形状修复是牙科修复CAD系统的核心问题,其中结构特征线,如颈缘线、修复边缘线是决定修复体制造精度的关键要素.针对现有牙齿形状自动修复算法未考虑结构特征线附近的咬合面形状约束以及仅能处理部分缺失情况的问题,提出了结合模版特征线匹配与移动最小二乘变形的修复体曲面重建算法.该算法采用智能剪刀算法半自动指定牙齿预备体上的结构特征线,并采用曲面拟合技术将该结构特征线投影至模版牙齿模型以建立曲线约束;再用近似刚性的移动最小二乘变形算法将模版牙齿模型匹配到牙齿预备体上;最后将移动最小二乘变形算法并行化,实现了以特征线为控制句柄的修复体形状交互设计.实验结果表明,由于引入了曲线约束,文中算法重建的修复体在结构特征线附近可获得更自然的咬合面形态.
Tooth shape restoration is an essential problem of dental restoration CAD system, in which structural feature lines like cervical margin lines and boundaries of restoration regions are the key elements for guaranteeing the accuracy of dental restorations. In order to solve the problems of existing methods that the morphology of the occlusal surfaces near the structural feature lines are not constrained and only partially missing cases are dealt with, we propose a reconstruction algorithm combining template feature line matching and moving least square （MLS） deformation. Firstly, the structural feature lines lying on the tooth preparation are specified using an intelligent scissor algorithm and projected onto the template tooth model using surface fitting technique to establish curve constraints. Then the template tooth model is aligned to the tooth preparation using as-rigid-as- possible MLS deformation. Finally, we parallelize the implementation of the MLS deformation to support feature line guided real-time interactive design of the occlusal surface. Experimental results show that, thanks to the curve constraints, high quality occlusal surfaces near structural feature lines are obtained.
出处
《计算机辅助设计与图形学学报》
EI
CSCD
北大核心
2014年第2期280-286,共7页
Journal of Computer-Aided Design & Computer Graphics
基金
浙江省重大科技专项计划项目(2011C13009)
关键词
牙科修复CAD系统
特征线匹配
移动最小二乘变形
近似刚性
曲线约束
dental restoration CAD system
feature line matching
moving least square deformation
as-rigid-as-possible
curve constraints
