Lynnerup Niels, Clausen Maja-Lisa, Kristoffersen Agnethe May, Steglich-Arnholm Henrik
Laboratory of Biological Anthropology, Institute of Forensic Medicine, University of Copenhagen, Copenhagen, Denmark.
Forensic Sci Med Pathol. 2009;5(3):167-73. doi: 10.1007/s12024-009-9094-8. Epub 2009 Jun 9.
Surface scanning of the face of a suspect is presented as a way to better match the facial features with those of a perpetrator from CCTV footage. We performed a simple pilot study where we obtained facial surface scans of volunteers and then in blind trials tried to match these scans with 2D photographs of the faces of the volunteers. Fifteen male volunteers were surface scanned using a Polhemus FastSCAN Cobra Handheld Laser Scanner. Three photographs were taken of each volunteer's face in full frontal, profile and from above at an angle of 45 degrees and also 45 degrees laterally. Via special software (MIMICS and Photoshop) the surface scans were matched with the photographs in blind trials. The matches were graded as: a good fit; possible fit; and no fit. All the surface scans and photos were matched correctly, although one surface scan could be matched with two angled photographs, meaning that the discriminatory value was 86.7%. We also tested the surface scanner in terms of reliability in establishing point measures on skulls, and compared with physical measurements performed by calipers. The variation was on average 1 mm for five cranial measures. We suggest how surface scanning might be applied in forensic facial identification.
对嫌疑人面部进行表面扫描，是一种将面部特征与来自闭路电视录像的犯罪者面部特征进行更好匹配的方法。我们进行了一项简单的初步研究，获取了志愿者的面部表面扫描图像，然后在盲测中尝试将这些扫描图像与志愿者面部的二维照片进行匹配。使用Polhemus FastSCAN Cobra手持式激光扫描仪对15名男性志愿者进行了表面扫描。为每位志愿者的面部拍摄了三张照片，分别是正脸、侧脸以及从上方45度角和侧面45度角拍摄的照片。通过特殊软件（MIMICS和Photoshop）在盲测中将表面扫描图像与照片进行匹配。匹配结果分为：匹配良好；可能匹配；不匹配。所有的表面扫描图像和照片都正确匹配，不过有一次表面扫描图像可以与两张角度照片匹配，这意味着辨别率为86.7%。我们还测试了表面扫描仪在颅骨上建立点测量的可靠性，并与用卡尺进行的物理测量进行了比较。五项颅骨测量的平均偏差为1毫米。我们提出了表面扫描在法医面部识别中的应用建议。
