增材修复中的三角网格尖锐特征重建方法  

Sharp Feature Reconstruction Method for Triangular Meshes in Additive Repair

作　　者：朱峰 梁浚哲 梁晋[1] 巫志辉 汪运 任茂栋 ZHU Feng;LIANG Junzhe;LIANG Jin;WU Zhihui;WANG Yun;REN Maodong(College of Mechanical Engineering,Xi′an Jiaotong University,Xi′an 710049,China;School of Microelectronics,Xi′an Jiaotong University,Xi′an 710049,China;Innovation Lab,XTOP 3D Technology(Xi′an)Co.Ltd.,Xi′an 710049,China)

机构地区：[1]西安交通大学机械工程学院,西安710049 [2]西安交通大学微电子学院,西安710049 [3]新拓三维(西安)有限公司创新实验室,西安710049

出　　处：《光子学报》2024年第12期33-43,共11页Acta Photonica Sinica

基　　金：国家重点研发计划(No.2022YFB4601802);国家自然科学基金(No.52275543)。

摘　　要：增材修复过程中通常将结构光扫描得到的点云数据封装成三角网格,由此过程得到的三角网格会损失原物体的尖锐特征。为了解决这一问题,设计了三角网格尖锐特征重建算法,对三角网格尖锐特征的检测和重建技术进行了研究。首先,检测每个三角面片法向量与邻域面的法向量夹角,如果存在超过一定阈值的夹角,将该三角面片判断为特征面片,并记录保存。接着,对于一簇特征面的最外围特征面,根据其相似面片法向量方向对此特征面法向量方向进行调整。然后,根据调整后的法向量来调整此特征面的顶点位置,使调整后的三角面片尽可能垂直于调整后的法向量。最后,将处理后的特征面片置为非特征面片,并重新执行上述全部步骤直到全部特征面片处理完成。实验结果表明:锐化的运行时间随着面片数量增加而增加,十万个三角面片的锐化时间在10 s以下。该锐化方法应用于不同疏密程度的三角网格效果比较稳定,对具有大量噪声的三角网格也能有效进行锐化,基本满足重建已经损失的尖锐特征的要求。In the process of additive repair,the point cloud data obtained by scanning the workpiece with structured light is usually encapsulated into a triangular mesh.Due to interference in the scanning environment or blurring of sharp features during point cloud post-processing,the sharp features that originally existed in the workpiece will be lost,making it impossible to restore the true appearance of the workpiece in the final triangular mesh.To solve this problem,this paper designs an algorithm for reconstructing sharp features in triangular meshes and studies the detection and reconstruction techniques of sharp features in triangular meshes.Firstly,the angle between the normal vector direction of each triangular patch and the normal vector direction of its neighboring faces is detected.The selected neighboring face is a ring of neighboring faces of the triangular patch,that is,the triangular patch has common edges or vertices with these neighboring faces.If there is an angle exceeding a certain threshold between the normal vector of the patch and the normal vector of the neighboring face,the triangular patch is set as a feature patch,and the feature patch is recorded and saved in a set.Next,traverse each feature patch in the set,determine whether it is the outermost feature patch,that is,whether it is adjacent to a non feature surface.If it is adjacent to a non feature surface,enter the processing step for that feature patch,find its similar patch in the non feature patches in its neighborhood,and adjust the normal vector direction of this feature patch according to the normal vector direction of the similar patch,so that the normal vector direction of this feature patch is as parallel as possible to the normal vector direction of the similar patch.Then,continue to adjust the positions of the three vertices of the feature patch,adjust the vertex positions of the feature patch according to the direction of the normal vector adjusted in the previous step,so that the adjusted triangular patch is as perpendicular as po

关 键 词：计算机图形学 网格锐化 网格特征检测 三角网格 增材修复 

分 类 号：TP751[自动化与计算机技术—检测技术与自动化装置]