基于三维激光扫描的颅骨测量与手工测量的比较

A comparison between cranial measurements using three-dimensional laser scanning technology and manual measurements

基于三维激光扫描的颅骨测量方法具有无接触、成像快速、易便携操作等优势,近年来在体质人类学与古人类学等领域发挥着日趋重要的作用。而在该测量技术普及的同时,其可靠性以及与手工测量的一致性问题也受到关注。本研究分别以手工方法与激光扫描建立模型法对考古出土颅骨进行测量,期望以实验手段探讨两种测量结果是否一致。实验结果显示,上述两种测量方法分别标定的两套测点相互之间吻合情况较好。其中,有易识别解剖学形态特征的测点吻合程度最优。而在两种测量手段的标点操作方式有所不同时,其标点位置间距会略有放大。从最终测量结果来看,两种测量手段所获数据的绝对差值和相对差异程度均较小。个别测量项在配对样本t检验中表现出了差异显著性,这应由两种测量结果大小差异的统一偏向性所致。在实际操作中,此类差异仍在可接受范围内,适宜混合同时使用。就差异的来源而言,测量操作方式的不同以及测点间的吻合程度是导致最终测量结果不同的主要原因之一,而仪器、颅骨表面的激光反射特性、扫描所获三维画面拼合情况等主客观因素也同样不可忽视。

Compared with traditional manual measurements,three-dimensional laser scanning technology is considered a method with better performance in terms of convenience and efficiency. Although such technology is being utilized in physical anthropology and paleoanthropology in recent years,some questions have emerged. For instance,whether 3D virtual images are acceptable and the measurement values based on them can be compatible with the manual ones. Here,to compare the differences between two measurement systems,we tried to measure skulls by both methods. The results show that landmarks digitized from the 3D virtual image and real skulls overlap basically. Specifically,those landmarks with typical morphology features usually show better goodness of fit,while other landmarks set by two methods in diverse ways tend to separate slightly in comparison. As for the measurement values,most of data generated by traditional manual methods are compatible with those from the 3D virtual image. Although several measurement values show significant differences when undergoing a paired t-test,such differences may have limited practical implications. Besides,the main source of such differences could be the method to set landmarks and the goodness of fit of those landmarks, while other factors like the performance of equipment,the reflectivity of skulls、 surface,and the accuracy of alignment of 3D images acquired from scanning cannot be ignored.