Josh P. Davis

Computer assisted photo-anthropometric analyses of full-face and profile facial images

Expert witnesses using facial comparison techniques are regularly required to disambiguate cases of disputed identification in CCTV images and other photographic evidence in court. This paper describes a novel software-assisted photo-anthropometric facial landmark identification system, DigitalFace tested against a database of 70 full-face and profile images of young males meeting a similar description. The system produces 37 linear and 25 angular measurements across the two viewpoints. A series of 64 analyses were conducted to examine whether separate novel probe facial images of target individuals whose face dimensions were already stored within the database would be correctly identified as the same person. Identification verification was found to be unreliable unless multiple distance and angular measurements from both profile and full-face images were included in an analysis.

Evolving and combining facial composites: Between-witness and within-witness morphs compared.

Student participant-witnesses produced 4 composites of unfamiliar faces with a system that uses a genetic algorithm to evolve appearance of artificial faces. Morphs of 4 composites produced by different witnesses (between-witness morphs) were judged better likenesses (Experiment 1) and were more frequently named (Experiment 2) by participants who were familiar with the target actors than were morphs of 4 composites produced by a single witness (within-witness morphs). Within-witness morphs were judged better likenesses and more frequently named than the best or the first-produced individual composites. The same results for likeness judgments were observed after possible artifacts in the comparison of between- and within-witness morphs were eliminated (Experiment 3). Experiment 4 showed that both internal and external features were better represented in morphs than in the original composites, although the representation of internal features improved more. The results suggest that morphing improves the representation of faces by reducing random error. Between-witness morphs yield more benefit than within-witness morphs by reducing consistent but idiosyncratic errors of individual witnesses. The experiments provide the first demonstration of an advantage for within-witness morphs produced using a single system. Experiment 2 provides the first demonstration of a reliable advantage for between-witness morphs in the most forensically relevant task: naming a composite of a familiar person produced by a witness who was unfamiliar with the target. Morphing would enhance the recognition of facial composites of criminals. Within-witness morphing provides a methodology for use in crimes in which the victim is the only witness.

Identification on the street: A field comparison of police street identifications and video line-ups in England

A street identification or live show-up provides an eyewitness with an opportunity to identify a suspect shortly after a crime. In England, the majority of suspects identified are subsequently included in a video line-up for the same witness to view. In Study 1, robbery squad data from three English police forces recorded 696 crimes, the identification procedures employed and prosecution decisions. A street identification was the most frequent identification procedure, being attempted in 22.7% of investigations, followed by mugshot albums (11.2%) and video line-ups (3.4%). In Study 2, data of 59 crimes were collected in which suspects, identified in a street identification, were subsequently filmed for a video line-up. Across both studies, most (84%) suspects identified in the street were subsequently identified in a video line-up, indicative of a commitment effect, in which a witness conforms to their first identification decision. All suspects identified in two procedures were eventually cautioned or charged to appear in court. The ground truth of suspect guilt in these field data cannot be determined. However, suggestions are made for reducing the likelihood of a mistaken identification of an innocent suspect caught up in an investigation; all possible steps should be taken to reduce the inherent suggestiveness of the street identification procedure.

Craniofacial Identification: Facial image comparison

In this chapter, the problems associated with the individualisation of people depicted in photographic forensic evidence such as closed circuit television (CCTV) images are described. Evidence of this type may be presented in court and, even with highquality images, human identification of unfamiliar faces has been shown to be unreliable. Therefore, facial image comparison or mapping techniques have been developed. These have been used by expert witnesses providing opinion testimony as to whether two images depict the same person or not. With photographic video superimposition, one image is superimposed over a second so that a series of visual tests can detect differences or similarities in facial features. With morphological comparison analysis facial features are classified into discrete categories, providing an indication of whether these are similar across images. Finally, with photo-anthropometry the proportional distances and sometimes the angles between facial landmarks are calculated and compared. Recent research using each technique is described, and the difficulties associated with their application in forensic settings evaluated. As present, no method provides certainty of identification and great care should be taken if presented in court to obtain a conviction without substantiating alternative evidence.

A Comparison of Individual and Morphed Facial Composites Created Using Different Systems

An evaluation of individual and morphed composites created using the E-FIT and EFIT-V production systems was conducted. With the assistance of trained police staff, composites of unfamiliar targets were constructed from memory following a Cognitive Interview. EFIT-V composite production followed either a two-day delay, or on the same day as viewing a video of the target. E-FIT composites were created on the same day as viewing the target video. Morphs were produced from merging either two, or three composites created by the same witness, but with the assistance of a different operator. Participants familiar with the targets supplied similarity-to-target photograph ratings. No differences were found in the rated quality of composites created using E-FIT or EFIT-V, although a two-day delay in production resulted in inferior images. Morphs were rated as better likenesses than individual composites, although the benefits were greater with EFIT-Vs. Encouraging witnesses to create more than one composite image for subsequent morphing might enhance the likelihood of recognition of facial composites of criminals.

An evaluation of post-production facial composite enhancement techniques

Purpose – The purpose of this paper is to describe four experiments evaluating post-production enhancement techniques with facial composites mainly created using the EFIT-V holistic system. Design/methodology/approach – Experiments 1-4 were conducted in two stages. In Stage 1, constructors created between one and four individual composites of unfamiliar targets. These were merged to create morphs. Additionally in Experiment 3, composites were vertically stretched. In Stage 2, participants familiar with the targets named or provided target-similarity ratings to the images. Findings – In Experiments 1-3, correct naming rates were significantly higher to between-witness 4-morphs, within-witness 4-morphs and vertically stretched composites than to individual composites. In Experiment 4, there was a positive relationship between composite-target similarity ratings and between-witness morph-size (2-, 4-, 8-, 16-morphs). Practical implications – The likelihood of a facial composite being recognised can be improv...

Holistic Facial Composite Construction and Subsequent Lineup Identification Accuracy: Comparing Adults and Children

ABSTRACT When the police have no suspect, they may ask an eyewitness to construct a facial composite of that suspect from memory. Faces are primarily processed holistically, and recently developed computerized holistic facial composite systems (e.g., EFIT-V) have been designed to match these processes. The reported research compared children aged 6–11 years with adults on their ability to construct a recognizable EFIT-V composite. Adult constructors EFIT-Vs received significantly higher composite-suspect likeness ratings from assessors than childrens, although there were some notable exceptions. In comparison to adults, the child constructors also overestimated the composite-suspect likeness of their own EFIT-Vs. In a second phase, there were no differences between adult controls and constructors in correct identification rates from video lineups. However, correct suspect identification rates by child constructors were lower than those of child controls, suggesting that a childs memory for the suspect can be adversely influenced by composite construction. Nevertheless, all child constructors coped with the demands of the EFIT-V system, and the implications for research, theory, and the criminal justice system practice are discussed.

Holistic Facial Composite Creation and Subsequent Video Line-up Eyewitness Identification Paradigm

The paradigm detailed in this manuscript describes an applied experimental method based on real police investigations during which an eyewitness or victim to a crime may create from memory a holistic facial composite of the culprit with the assistance of a police operator. The aim is that the composite is recognized by someone who believes that they know the culprit. For this paradigm, participants view a culprit actor on video and following a delay, participant-witnesses construct a holistic system facial composite. Controls do not construct a composite. From a series of arrays of computer-generated, but realistic faces, the holistic system construction method primarily requires participant-witnesses to select the facial images most closely meeting their memory of the culprit. Variation between faces in successive arrays is reduced until ideally the final image possesses a close likeness to the culprit. Participant-witness directed tools can also alter facial features, configurations between features and holistic properties (e.g., age, distinctiveness, skin tone), all within a whole face context. The procedure is designed to closely match the holistic manner by which humans’ process faces. On completion, based on their memory of the culprit, ratings of composite-culprit similarity are collected from the participant-witnesses. Similar ratings are collected from culprit-acquaintance assessors, as a marker of composite recognition likelihood. Following a further delay, all participants — including the controls — attempt to identify the culprit in either a culprit-present or culprit-absent video line-up, to replicate circumstances in which the police have located the correct culprit, or an innocent suspect. Data of control and participant-witness line-up outcomes are presented, demonstrating the positive influence of holistic composite construction on identification accuracy. Correlational analyses are conducted to measure the relationship between assessor and participant-witness composite-culprit similarity ratings, delay, identification accuracy, and confidence to examine which factors influence video line-up outcomes.

Masters of disguise: Super-recognisers' superior memory for concealed unfamiliar faces

The deployment of police super-recognisers (SRs) with exceptional face recognition ability, has transformed the manner in which some forces manage CCTV evidence. In London, SRs make high numbers of sometimes disguised suspect identifications from CCTV. In two experiments measuring immediate and one-week memory of unfamiliar faces in disguise, SRs were more accurate and confident than controls at correctly identifying targets, and ruling out faces not seen before. Accuracy and confidence were highest when targets wore no disguise, followed by hat and plaster, sunglasses, and balaclavas respectively. Even in the balaclava condition, SRs were more accurate than chance levels. These findings add to an accumulating body of empirical evidence demonstrating that SRs possess wide-ranging enhanced face processing abilities, and their deployment should complement ever advancing computerised face recognition systems.