1,721,003 research outputs found
Digital Image Analysis and Evaluation (DIAnE): A Forensic Image Processing Tool using MATLAB
Full text linkEFIT-V - Interactive Evolutionary Generation of Facial Composites for Criminal Investigations
No full textHolistic facial composite creation and subsequent video line-up eyewitness identification paradigm
Full text linkThe 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
Graphite Furnace Atomic Absorption Elemental Analysis of Ecstasy Tablets
Full text linkAbstract: Six metals (Cu, Mg, Ba, Ni, Cr, Pb) were determined in two separate batches of seized ecstasy
tablets by graphite furnace atomic absorption spectroscopy (GFAAS) following digestion with nitric
acid and hydrogen peroxide. Large intra-batch variations were found as expected for tablets produced
in clandestine laboratories. For example, nickel in batch 1 was present in the range 0.47-13.1 ppm and
in batch 2 in the range 0.35-9.06 ppm. Although batch 1 had significantly higher MDMA content than
batch 2, barium was the only element which discriminated between the two ecstasy seizures (batch 1:
0.19-0.66 ppm, batch 2: 3.77-5.47 ppm)
New methodology in facial composite construction: from theory to practice.
No full textExisting commercial, computerised techniques for constructing facial composites generated from eyewitness memory are essentially electronic versions of the original, mechanical feature-based systems such as PhotoFIT and Identikit. The effectiveness of this feature-based approach is fundamentally limited by the witness's ability to recall and verbalise accurate descriptions of facial features from memory. Recent advances in facial composite methodology have led to software systems that do not rely on this process but instead exploit a cognitively less demanding process of recognition. We provide a technical overview of the EFIT-V system, currently being used by a number of police services in the UK
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