Comparative studies of the accuracy and stability of three dimensional measuring methods for facial configurations, especially the external nose
Comparative studies of the accuracy and stability of three dimensional measuring methods for facial configurations, especially the external nose
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面部形态尤其是外鼻三维测量方法精度和稳定性比较研究
DOI：
10.5794/jjoms.38.1645
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
M. Sakuda
中科院分区：
文献类型：
--
作者：
K. Mishima;T. Sugahara;Y. Mori;K. Minami;Y. Tsukamoto;T. Kawamoto;M. Sakuda
有两种精确的方法来测量面部结构，特别是外鼻，作为三维物体。一种是激光扫描，它可以在不接触的情况下直接测量人脸。另一种方法是我们通常使用的，通过接触式高精度三维坐标测量系统（接触式测量系统）测量从牙印材料制成的面部印模中获得的石膏模型。本研究旨在评估这两种方法的准确性和稳定性，这是以前很少关注的问题。4名25岁无面部畸形的男性用这些系统进行了检查。从每个受试者身上取多个石膏模型来研究模型的稳定性。所有数据都被整合到三维模型中，以计算机图形的形式显示，并通过“最佳拟合程序”进行比较，该程序可以处理和叠加两组曲面数据，从而在曲面的每个位置得出法向量方向的最小差异。两套系统在同一石膏模型上得到的两组曲面数据除了鼻翼槽区域外几乎完全相同。在来自激光扫描系统的数据中，在悬垂区域周围注意到超过1.0 mm的畸变。激光扫描系统获得的面部与石膏模型数据拟合良好，数据偏差在0.2 ~ 0.3 mm之间，显示了面部石膏模型的高精度。用接触式测量系统检测石膏模型的稳定性，数据偏差为0.1-0.2 mm。总之，虽然本研究中采用的两种系统具有不同的特点，但都具有很高的准确性，对临床测量有用。
There are two accurate methods to measure facial configurations, especially the external nose, as three dimensional objects. One is laser-scanning which can immediately measure faces directly and without contact. The other method, which we usually use, measures plaster models, obtained from facial impressions made with dental impression materials, by means of a contact-type, high accuracy three dimensional coordinate measuring system (contact measuring system).This study was designed to assess the accuracy and stability of these two methods, an issue previously paid little attention. Four 25-year-old men without facial deformity were examined with these systems. Multiple plaster models were taken from each subject to investigate model stability. All data were integrated into three dimensional models, shown as computer graphics, and compared by the “best fit program, ” which can handle and superimpose the two sets of curved surface data to derive minimum differences in normal vector direction at every site of the surface.The two sets of curved surface data obtained from the same plaster model by each system were almost identical except for areas of the alar groove. In data derived from the laser-scanning system, more than 1.0 mm of distortion was noted around areas of overhang. Facial and plaster model data obtained by the laser-scanning system showed very good fit, with deviation between data being 0.2-0.3 mm.These results show the high accuracy of facial plaster models. The stability of plaster models was also examined with a contact measuring system and deviation between data was 0.1-0.2 mm. In conclusion, although the two systems employed in this study have different characteristics, both are highly accurate and useful for clinical measurement.