基于最短曲面距离对3dMD立体摄影系统测量精度和稳定性的研究

A study of mearment accuracy and repeatability of the 3dMD stereophotogrammetry System based on the shortest surface distance

目的:利用最短曲面距离验证3d MD立体摄影系统测量的精度和稳定性,对3d MD立体摄影系统的测量精度进行更为客观的评价。方法:被测物是表面贴有坐标格的直径14 cm的圆柱体模型,用3d MD立体摄影系统获取模型的表面数据,并利用该系统的测量工具测量模型上42个曲面距离,分别与对应的标准值进行统计学分析。结果:横向2格组、横向5格组、横向7格组和竖向7格组的测量值与标准值之间的差异有统计学意义(P<0.05);竖向2格组、竖向5格组的差异无统计学意义(P>0.05),但各组的误差均值都不超过0.3 mm;描述统计分析得出6组特征曲线长度的标准差均<0.1 mm,各测量组四分位数间距均≤0.15 mm。结论:3d MD立体摄影系统在测量曲面距离时精度高,稳定性好。

Objective：To evaluate the measurement accuracy and repeatability based on the shortest surface distance,obtain a more objective assessment about the 3d MD stereophotogrammetry System. Method：Under ideal circumstances,a cylinder model with grided surface and 14 cm diameter is used to examine the accuracy and the repeatability of the 3d MD stereophotogrammetry System.The 42 shortest surface distances of the cylinder model were measured in the software compare to direct microscope measurements correspondingly. Result：According to the statistical analysis,the differences between the surface distances and standard values of the horizontal 2、horizontal 5 grids and horizontal 7 grids groups are statistically significant,There is no significant differences in the other groups.But the error of each measurement groups is less than 0.3 mm;According to the descriptive statistics analysis,the standard deviation of the length of the 6 groups is less than 0.1 mm,and the Quartile of each measurement group is no more than 0.15 mm. Conclusion：These results suggest that the surface distances measured by 3d MD stereophotogrammetry System are highly reliable.The measurement accuracy and repeatability is good enough for the clinical research.