Examining Interobserver Reliability of Metric and Morphoscopic Characteristics of the Mandible

Mandibular metric and morphological characteristics have long been used for sex and ancestry estimation. Currently, there are no large‐scale studies examining interobserver agreement, particularly examining the role of observer experience. This study examines the interobserver agreement of six morphoscopic and eleven metric mandibular variables. Four observers with varied levels of experience scored 183 mandibles from the William M. Bass Donated Skeletal Collection. Absolute agreement and consistency were evaluated with the intraclass correlation coefficient (ICC). Additionally, technical error of measurement (TEM) and relative TEM (%TEM) were calculated for each metric variable. All analyses were conducted twice—once with all observers and again with only experienced observers. Results show mean morphoscopic agreement of 0.543 among all observers and 0.615 for experienced observers, and mean metric agreement of 0.886 among all observers and 0.911 for experienced observers. Further, no TEM exceeded 2 mm. All results were significant (p < 0.001).     

Proximal End Root Morphology Characteristics in Antemortem Anagen Head Hairs

The proximal end morphology of antemortem anagen head hair was compared with the characteristics documented to occur in postmortem hairs. Antemortem anagen and telogen head hairs (N = 967) were recovered following exposure to seven environments. Root morphology characteristics consistent with those reported in postmortem hairs were observed in 66 (14%) hairs exposed to a water, normal saline, outdoor soil, or indoor shower environment. Thirty‐three anagen hairs (7%) exhibited a root band at the proximal end. The mean distance from the root tip to the onset of the root band ranged from 0.23 to 0.7 mm, depending on the environment. The mean distance from the root tip to the onset of the root band was 0.46 mm, with a mean band length of 0.44 mm. The results illustrate the need to better characterize postmortem banding through quantitative measurements, including the range for root tip to band distance and the overall band length.     

Forensic Facial Approximation: Study of the Nose in Brazilian Subjects

Forensic facial approximation is an auxiliary method for human identification and allows facial recognition. The midface, that includes the nose, is vital for the recognition of a familiar face. The purpose of this study was to set hard tissue parameters to estimate nasal width, to test the method to estimate nasal width of Brazilians, and to analyze the relationship between nasal profile and facial type. A total of 246 computed tomography scans (183 females and 63 males) of adults were analyzed in Horos. Bone tissue measurements and facial type classification were performed on the skull scan. Nasal profile morphology was accessed through the tool 3D surface rendering. There was a difference around 3 mm from real to predicted nose through the method to estimate nasal width in Brazilians. So, the method may be used in forensic practice. Straight nose was associated with long face type.     

Does residency matter? Local residency as a predictor of arrest

Prior studies show that a number of offender characteristics impact police officer use of discretion. Although there are exceptions, characteristics such as race and gender have been shown to influence decisions made by police officers with racial/ethnic minorities and men more likely to be arrested than their counterparts. Yet, much less is known about the impact of morphology, an important component from Black’s Behavior of Law, on enforcement decisions. Using 2014 state-wide data on Class ‘B’ arrests in Idaho, we examine the role of morphology, as operationalized by offender residency in the community in which the violation occurred, on the odds of a police officer affecting an arrest as opposed to writing a citation for the violation. Results of logistic regression models show that local residents are significantly less likely to experience an arrest than non-residents. Theoretical explanations and implications for these findings are offered.     

Performance of forensic facial comparison by morphological analysis across optimal and suboptimal CCTV settings

Facial comparison is an important yet understudied discipline in forensics. The recommended method for facial comparison in a forensic setting involves morphological analysis (MA) with the use of a facial feature list. The performance of this approach has not been tested across various closed-circuit television (CCTV) conditions. This is of particular concern as video and image data available to law enforcement is often varied and of subpar conditions. The present study aimed at testing MA across two types of CCTV data, representing ideal and less than ideal settings, also assessing which particular shortcomings arose from less-than-ideal settings. The study was conducted on a subset of the Wits Face Database arranged in a total of 225 face pools. Each face pool consisted of a target image obtained from either a high-definition digital CCTV camera or a low-definition analogue CCTV camera in monochrome, contrasted to 10 possible matches. The face pools were analysed and scored using MA and confusion matrices were used to analyse the outcomes. A notably high chance corrected accuracy (CCA) (97.3%) and reliability (0.969) was identified across the digital CCTV sample, while in the analogue CCTV sample MA appeared to underperform both in accuracy (CCA: 33.1%) and reliability (0.529). The majority of the errors in scoring resulted in false negatives in the analogue sample (75.2%), while across both CCTV conditions false positives were low (digital: 0.3%; analogue: 1.2%). Even though hit rates appeared deceptively high in the analogue sample, the various measures of performance used and particularly the chance corrected accuracy highlighted its shortfalls. Overall, CCTV recording quality appears closely associated to MA performance, despite the favourable error rates when using the Facial Identification Scientific Working Group feature list.     

一种AI换脸方法生成的伪造视频分析

深度伪造(Deepfake)是一种将图像篡改与AI相结合的面部替换方法。本文首先介绍了Deepfake的产生背景和发展状况,介绍了相应检测技术的研究状况,并对相关文献进行归纳;然后探究了Deepfake运行的基本构架和核心部件,给出了视频面部替换的基本流程和步骤,并阐释了利用自编码网络进行脸部图像训练和转换的原理;最后,从视频的基本信息、编辑痕迹、违背摄影规律、视频整体和案情五个方面与原始视频作对比,分析这类伪造视频存在的问题。深度伪造技术在推动娱乐和文化发展的同时也产生了大量恶意的换脸视频,对国家安全、社会稳定和个人隐私造成潜在的威胁,本文通过对Deepfake实现原理的研究和伪造视频特征的分析,希望能够为该类视频的真伪检验提供一定的理论支持。     

Validation of the New Interpretation of Gerasimov's Nasal Projection Method for Forensic Facial Approximation Using CT Data,

The most common method to predict nasal projection for forensic facial approximation is Gerasimov's two‐tangent method. Ullrich H, Stephan CN (J Forensic Sci, 2011; 56: 470) argued that the method has not being properly implemented and a revised interpretation was proposed. The aim of this study was to compare the accuracy of both versions using a sample of 66 postmortem cranial CT data. The true nasal tip was defined using pronasale and nasal spine line, as it was not originally specified by Gerasimov. The original guidelines were found to be highly inaccurate with the position of the nasal tip being overestimated by c. 2 cm. Despite the revised interpretation consistently resulting in smaller distance from true nasal tip, the method was not statistically accurate (p > 0.05) in positioning the tip of the nose (absolute distance >5 mm). These results support that Gerasimov's method was not properly performed, and Ullrich H, Stephan CN (J Forensic Sci, 2011; 56: 470) interpretation should be used instead.     

Effect of Head Position on Facial Soft Tissue Depth Measurements Obtained Using Computed Tomography

Facial soft tissue depth (FSTD) studies employing clinical computed tomography (CT) data frequently rely on depth measurements from raw 2D orthoslices. However, the position of each patient's head was not standardized in this method, potentially decreasing measurement reliability and accuracy. This study measured FSTDs along the original orthoslice plane and compared these measurements to those standardized by the Frankfurt horizontal (FH). Subadult cranial CT scans (n = 115) were used to measure FSTDs at 18 landmarks. Significant differences were observed between the methods at eight of these landmarks (p < 0.05), demonstrating that high‐quality data are not generated simply by employing modern imaging modalities such as CT. Proper technique is crucial to useful results, and maintaining control over head position during FSTD data collection is important. This is easily and most readily achieved in CT techniques by rotating the head to the FH plane after constructing a 3D rendering of the data.