Prioritising quality: investigating the influence of image quality on forensic facial comparison.

Morphological analysis in forensic facial comparison was recently validated for judicial use. However, no image quality assurance systems exist for this purpose, despite image triage being considered the best practice approach. Hence, this study aimed at testing a semi-quantitative scoring method to assess image quality and investigated facial image resolution and lighting quality quantitatively in a context of forensic facial comparison. For this purpose, 400 facial comparison photographic and CCTV image pools developed from the Wits Face Database were used. These facial images were analysed in prior studies that investigated the validity of morphological analysis. A semi-quantitative image quality scoring system was adapted and tested on the above sample and compared across correct and incorrect matches obtained as part of previous studies using a logistic regression model. In addition, facial images were cropped to the closest pixel comprising the face, head and neck areas; then, a face-to-image pixel proportion was calculated as an estimator of resolution quality; and pixel exposure qualities were obtained to be compared to facial comparison outcomes. Ideal and high image quality scores were related to correctness of matches, while low-quality scores were related to incorrect matches. High pixel proportions were related to true matches and low exposure was related to false positives, while high exposure was related to false negatives. These results suggest that an easy method for image triage could be employed by scoring image quality. Quantitative measures should be investigated further for thresholding quality suitability for confidence of facial comparisons.

Forensic Facial Comparison: Current Status, Limitations, and Future Directions.

Global escalation of crime has necessitated the use of digital imagery to aid the identification of perpetrators. Forensic facial comparison (FFC) is increasingly employed, often relying on poor-quality images. In the absence of standardized criteria, especially in terms of video recordings, verification of the methodology is needed. This paper addresses aspects of FFC, discussing relevant terminology, investigating the validity and reliability of the FISWG morphological feature list using a new South African database, and advising on standards for CCTV equipment. Suboptimal conditions, including poor resolution, unfavorable angle of incidence, color, and lighting, affected the accuracy of FFC. Morphological analysis of photographs, standard CCTV, and eye-level CCTV showed improved performance in a strict iteration analysis, but not when using analogue CCTV images. Therefore, both strict and lenient iterations should be conducted, but FFC must be abandoned when a strict iteration performs worse than a lenient one. This threshold ought to be applied to the specific CCTV equipment to determine its utility. Chance-corrected accuracy was the most representative measure of accuracy, as opposed to the commonly used hit rate. While the use of automated systems is increasing, trained human observer-based morphological analysis, using the FISWG feature list and an Analysis, Comparison, Evaluation, and Verification (ACE-V) approach, should be the primary method of facial comparison.

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.

Development of the Wits Face Database: an African database of high-resolution facial photographs and multimodal closed-circuit television (CCTV) recordings.

Forensic facial comparison is a commonly used, yet under-evaluated method employed in medicolegal contexts across the world. Testing the accuracy and reliability of facial comparisons requires large scale controlled and matching facial image databases. Databases that contain images of individuals on closed-circuit television (CCTV), with matching formal and informal photographs are needed for this type of research. Although many databases are available, the majority if not all are developed in order to improve facial recognition and face detection algorithms through machine learning, with very limited if any measure of standardisation. This paper aims to review the available databases and describe the development of a high resolution, standardised facial photograph and CCTV recording database of male Africans. The database is composed of a total of 6220 standardised and uncontrolled suboptimal facial photographs of 622 matching individuals in five different views, as well as corresponding CCTV footage of 334 individuals recorded under different realistic conditions. A detailed description of the composition and acquisition process of the database as well as its subdivisions and possible uses are provided. The challenges and limitations of developing this database are also highlighted, particularly with regard to obtaining CCTV video recordings and ethics for a database of faces. The application process to access the database is also briefly described.

Assessing the effect of facial disguises on forensic facial comparison by morphological analysis.

Disguises are commonly used to mask a person's facial appearance in areas under closed-circuit television (CCTV) surveillance. While many studies attempted to understand the effects of disguises, such as hats and glasses, on facial recognition, limited studies have looked at disguises in forensic facial comparison. The aim of this study was to compare the outcomes of forensic facial comparison by morphological analysis (MA) in a CCTV sample with sunglasses and brimmed caps. The sample was obtained from the Wits Face Database and organized into 81 face pools of one target facial image wearing a disguise (cap or sunglasses) and 10 potential matching images. MA was conducted across face pools, and confusion matrices were used to assess the outcomes. Surprisingly, sunglasses had limited effect on MA performance both in accuracy (90.4%) and in reliability (κ = 0.798), while caps markedly decreased both accuracy (68.1%) and reliability (κ = 0.639). Error rates were associated primarily with false negatives in both samples (caps: 42.4%; sunglasses: 16.1%) despite the sample distribution favoring false-positive errors, which were very low (caps: 0.6%; sunglasses: 0%). Similarly to other studies, hats and caps were more harmful to correct identification when compared to sunglasses, which actually resulted in better accuracy than regular CCTV recordings. The effect of brimmed caps on accuracy was attributed to the overall loss of facial information caused. On training analysts, it may be helpful to instruct purposefully avoiding overreliance on easily disguised facial features, as other regions of the face also contain substantial feature information.

Validation of forensic facial comparison by morphological analysis in photographic and CCTV samples.

Between the ever-increasing availability of surveillance evidence and expert-based forensic facial comparison being considered admissible in court, confirming its validity is paramount. Facial comparison is most commonly conducted using morphological analysis (MA), a largely untested feature-based approach. This study aimed at validating the current recommended practice of MA in both standardised and suboptimal surveillance samples. Face pools of 175 South African males were compiled with a series of facial photographs, using images from the Wits Face Database. The first 75 face pools consisted of wildtype (unstandardised) high-quality target photographs, while the remaining 100 face pools consisted of suboptimal closed-circuit television (CCTV) target images. Target images were compared to high-quality standardised photographs. Face pools were analysed using the Facial Identification Scientific Working Group's guidelines and feature list. Confusion matrices were used to determine the performance of MA in each cohort. MA was found highly accurate (chance-corrected accuracy (CCA): 99.1%) and reliable (κ = 0.921) in the photographic sample and less accurate (CCA: 82.6%) and reliable (κ = 0.743), in the CCTV sample. Higher false-positive and false-negative rates were noted for the CCTV sample, with the majority of errors resulting in false-negative outcomes. The decreased performance in the CCTV sample was attributed to various factors including image quality, angle of recording and lighting. Other studies testing facial comparison identified lower accuracies and reliability across various conditions. Better performance was found here and in other studies that included some form of facial feature list, reinforcing the importance of using a systematic facial feature list.

Evaluation of the Enhanced Computational Methods of Estimating Age-at-Death Using the Pubic Symphyses of a White South African Population.

To address problems of reproducibility related to current age estimation methods, the enhanced computational Methods (ECM) were previously developed using a sample of white North American male pubic symphyses and showed promise in improving current techniques. However, given the evidence of sex and population differences in the onset of age markers, this study set out to test the ECM on a white South African sample. The sample consisted of 184 well-preserved os coxae from individuals of known age and sex. Pubic symphyseal surfaces were scanned using the Artec Spider 3D scanner, processed using Artec Studio 10 and analyzed using forAge. Point estimates of age were then compared to the true age of each individual. Results indicate that the ECM performed poorly in a white South African population, with consistent underestimation of age-at-death and weak positive correlations with true age. Despite the low correlations, the ECM did, however, reduce observer error.

Facial ageing in South African adult males.

Knowledge of facial ageing is important in forensic facial approximation and photo identification. Previous studies mostly investigated facial ageing in European faces, and this research therefore aims to provide data on patterns of facial ageing in an African sample. One hundred eighty-nine black South African males aged 20 years and older were photographed in anterior and lateral views. Facial images were captured in a consistent position by using a Canon EOS 1300D camera and 18- to 55-mm EFS lens. Thirty individuals per decade were included, with the 80+ age category being limited to only nine participants. A facial ageing scoring system, based on previous research, was constructed for non-metric age changes such as appearance of wrinkles and sagging around the orbital area. Metric age changes such as ear lengthening and lip thinning were investigated separately. Results indicate that the ageing process in black South Africans has both similarities and differences to senescence described for European populations. Although most ageing features showed unidirectional change during time, these changes often occurred at a variable rate. Some features did not show a clear change with increasing age - these include mouth width increase, nasal elongation, nasal tip dropping, ear width increase and ear length increase. In addition to the age-feature correlations, an average face per decade was developed using Abrosoft FantaMorph Deluxe software. This provides a visual approximation of male South African faces captured at a single moment in time, as an aid for craniofacial depictions and facial image ageing in forensic practise.

The success of various management techniques used in South African children with type 1 diabetes mellitus.

BACKGROUND: Despite the availability of international guidelines for the treatment of type 1 diabetes mellitus in children, important aspects of treatment are not accessible to all young patients in South Africa (SA). OBJECTIVE: To investigate factors in diabetes management strategies that are associated with poor glycaemic control and decreased quality of life (QoL) in SA children with type 1 diabetes mellitus (T1DM). METHODS: Eighty children (mean (standard deviation) age 12.9 (2.7) years) with T1DM were asked to answer standardised questionnaires on demographics, management techniques used and perceptions of diabetes. The height and weight of each child was recorded and glycosylated haemoglobin (HbA1c) measured. Informed consent and assent for each participant was obtained before enrolment. RESULTS: A total of 51.4% of the participants had poor metabolic control, with an HbA1c level >10.0% (86 mmol/mol). Factors in clinical practice found to have a significant association with decreased HbA1c and/or QoL were healthcare system (p<0.001), insulin administration (p=0.001), correction dose (p=0.002), carbohydrate counting (p<0.001) and number of severe hyperglycaemic events (p=0.048). Regular exercise did not show any association with HbA1c classification or QoL. Children from single-parent households were prone to unsuccessful diabetes management regardless of treatment techniques used (p=0.002). CONCLUSIONS: The use of premixed insulin without access to rapid-acting insulin, absence of correction doses for hyperglycaemia and lack of carbohydrate counting showed significant association with poor diabetes management. Some recommendations regarding the adoption of more effective diabetes management strategies in the public healthcare system are suggested.