Second Forensic Biology Section, National Research Institute of Police Science, 6-3-1, Kashiwanoha, Kashiwa-shi, Chiba 277-0882, Japan.
Second Forensic Biology Section, National Research Institute of Police Science, 6-3-1, Kashiwanoha, Kashiwa-shi, Chiba 277-0882, Japan.
Forensic Sci Int. 2019 Sep;302:109878. doi: 10.1016/j.forsciint.2019.109878. Epub 2019 Jul 27.
Three-dimensional (3D) shape variations of the face and facial parts in Japanese adults were examined to collect basic data to be used for facial comparison in forensics. In total, 1000 3D facial scans (500 males, 500 females) of Japanese individuals were re-meshed into anatomically homologous shape models and analyzed by principal component analysis (PCA) after Procrustes superimposition. Facial parts (the nose and the mouth) were segmented from homologous face models and analyzed by PCA, too. Among all kinds of objects (the face, the nose, and the mouth), the most predominant shape variation represented by the first principal component (PC1) was the height-width proportion. The second largest variation (PC2) in the face and the nose was depth; for the mouth, it was the relative protrusion of the upper and lower lips. We interpreted predominant shape variations represented by the first five principal components (PCs) in each object. Asymmetric shape variations were observed within these PCs for the nose and the mouth. Sexual dimorphism of the face and the facial parts was also examined by testing the significance of sex-linked differences in PC scores. A significant difference was found between males and females for many PCs. Sexual dimorphism was examined also by emphasizing the shape difference between average male and female faces. Our results revealed predominant 3D shape variations and sexual dimorphism of the face and facial parts. The results may be informative for performing facial comparison in police investigations, an increasingly used technique.
本研究旨在采集日本人面部及各面部器官的三维（3D）形态变化数据，以期为法医学领域的面部比较提供基础资料。本研究共采集了 1000 名日本人的 3D 面部扫描数据（男、女各 500 名），所有数据均经过 Procrustes 叠加配准后重新网格化为解剖学同型形态模型，并进行主成分分析（PCA）。我们同样将同型面部模型中的鼻部和口部分割出来并进行 PCA 分析。在各种物体（面部、鼻部和口部）中，第一主成分（PC1）所代表的最主要的形态变化是高度与宽度的比例。在面部和鼻部中，第二大的形态变化（PC2）是深度，而在口部则是上下唇的相对突出度。我们对面部及各面部器官前五个主成分（PC）所代表的主要形态变化进行了阐释。在 PC 分析中，我们观察到了鼻部和口部的形态存在左右不对称性。通过检验各 PC 中性别相关分数的显著性差异，我们还研究了面部及各面部器官的性别二态性。在许多 PC 中，男性与女性之间存在显著差异。我们还通过强调平均男女性面部之间的形状差异来研究性二态性。我们的研究结果揭示了面部及各面部器官的 3D 形态变化和性别二态性。这些结果可能有助于警察调查中日益广泛应用的面部比较技术。
