中文摘要：

基于点云的几何测量方法是非接触式测量的重要方法。针对点云数据，提出了一种基于待定系数的二次曲面的几何测量方法，建立了求解不同二次曲面（球面、柱面和圆锥面）的统一框架。根据二次曲面方程与不同类型二次曲面几何量的关系，给出了球面、柱面和圆锥面的具体几何参数的求解方法。实验证明，该方法能在短时间内精确地测量所需的几何值，方法切实可行。

英文摘要：

Geometry measurement based on point cloud is an important non-contact measurement method. A quadratic surface geometry measurement method was proposed based on undetermined co- efficients for point cloud data. A unified framework for solving quadratic surface （including spherical, cylindrical and conical surface） was established. According to the quadratic surface equation and the different types geometric parameters of quadratic surface, the solving methods for the specific geometric parameters of the spherical, cylindrical and conical surface were implemented. Experimental re- sults show that the method can measure the desired geometric parameters from point cloud data quickly and accurately, and it is a practical and feasible method.