Jayaprakash Paul T
Forensic Science Program, Universiti Sains Malaysia, Kubang Kerian, 16150, Kelantan, Malaysia.
Forensic Sci Int. 2017 Sep;278:411.e1-411.e8. doi: 10.1016/j.forsciint.2017.04.021. Epub 2017 May 16.
Often cited reliability test on video superimposition method integrated scaling face-images in relation to skull-images, tragus-auditory meatus relationship in addition to exocanthion-Whitnall's tubercle relationship when orientating the skull-image and wipe mode imaging in addition to mix mode imaging when obtaining skull-face image overlay and evaluating the goodness of match. However, a report that found higher false positive matches in computer assisted superimposition method transited from the above foundational concepts and relied on images of unspecified sizes that are lesser than 'life-size', frontal plane landmarks in the skull- and face- images alone for orientating the skull-image and mix images alone for evaluating the goodness of match. Recently, arguing the use of 'life-size' images as 'archaic', the authors who tested the reliability in the computer assisted superimposition method have denied any method transition. This article describes that the use of images of unspecified sizes at lesser than 'life-size' eliminates the only possibility to quantify parameters during superimposition which alone enables dynamic skull orientation when overlaying a skull-image with a face-image in an anatomically acceptable orientation. The dynamic skull orientation process mandatorily requires aligning the tragus in the 2D face-image with the auditory meatus in the 3D skull-image for anatomically orientating the skull-image in relation to the posture in the face-image, a step not mentioned by the authors describing the computer assisted superimposition method. Furthermore, mere reliance on mix type images during image overlay eliminates the possibility to assess the relationship between the leading edges of the skull- and face-image outlines as also specific area match among the corresponding craniofacial organs during superimposition. Indicating the possibility of increased false positive matches as a consequence of the above method transitions, the need for testing the reliability in the superimposition method adopting concepts that are considered safe is stressed.
视频叠加法常用于对与颅骨图像整合缩放的面部图像进行可靠性测试，在对颅骨图像进行定位时，除了外眦-惠特纳尔结节关系外，还包括耳屏-外耳道关系，以及在获取颅骨-面部图像叠加时的擦除模式成像和混合模式成像，并评估匹配度。然而，一份报告发现，计算机辅助叠加法中存在较高的假阳性匹配，该方法从上述基础概念转变而来，依赖于未指定大小且小于“真人大小”的图像，仅依靠颅骨和面部图像中的额平面标志来定位颅骨图像，仅使用混合图像来评估匹配度。最近，测试计算机辅助叠加法可靠性的作者认为使用“真人大小”的图像“过时”，否认了任何方法转变。本文指出，使用小于“真人大小”的未指定大小的图像消除了叠加过程中量化参数的唯一可能性，而这一可能性是在以解剖学上可接受的方向将颅骨图像与面部图像叠加时实现动态颅骨定位所必需的。动态颅骨定位过程强制要求将二维面部图像中的耳屏与三维颅骨图像中的外耳道对齐，以便相对于面部图像中的姿势在解剖学上定位颅骨图像，而描述计算机辅助叠加法的作者并未提及这一步骤。此外，在图像叠加过程中仅依赖混合类型图像，消除了评估颅骨和面部图像轮廓前缘之间关系以及叠加过程中相应颅面器官之间特定区域匹配的可能性。由于上述方法转变可能导致假阳性匹配增加，强调了采用被认为安全的概念对叠加法的可靠性进行测试的必要性。
