Raul Sutton

Automated flexion crease identification using internal image seams

Palmar flexion crease recognition is a palmprint identification method for verifying biometric identity. This paper proposes a method of automated flexion crease recognition that can be used to identify palmar flexion creases in online palmprint images. A modified image seams algorithm is used to extract the flexion creases, and a matching algorithm, based on kd-tree nearest neighbour searching, is used to calculate the similarity between them. Experimental results show that in 1000 images from 100 palms, when compared to manually identified flexion creases, a genuine acceptance rate of 100% can be achieved, with a false acceptance rate of 0.0045%.

The relative DNA-shedding propensity of the palm and finger surfaces.

The relative DNA shedding propensity of palmar and finger surfaces has not previously been examined. In the study presented here, palm and fingermarks of six volunteers were analysed for DNA recovery, after deposition at a pressure of approximately 4900 Pa onto glass plates or slides, respectively. The marks were swabbed; DNA extracted using a modified Chelex® method, and then quantified using qPCR, followed by genotype analysis. To assess the availability of DNA-containing material on the skin surface, DNA was analysed by directly swabbing the palm and fingerprint areas of the skin. A further set of palm and fingermarks was subjected to microscopic examination. The results demonstrated that the quantity of DNA shed from the palmar surface is significantly less than from two fingers. Single donor DNA profiles were obtained from deposited fingermarks by applying a low copy number protocol (32 cycles). DNA retrieved from palm and fingers may be degraded, as suggested by reduced peak intensity and allelic dropout amongst the larger STR loci. These findings suggest that, owing to the low levels of DNA deposition, when palmar marks are found at crime scenes, every effort should be made to recover friction ridge detail to use as an identification metric, with collection for DNA analysis performed afterwards.

Latent fingermark pore area reproducibility.

The study of the reproducibility of friction ridge pore detail in fingermarks is a measure of their usefulness in personal identification. Pore area in latent prints developed using cyanoacrylate and ninhydrin were examined and measured by photomicrography using appropriate software tools. The data were analysed statistically and the results showed that pore area is not reproducible in developed latent prints, using either of the development techniques. The results add further support to the lack of reliability of pore area in personal identification.

Postmortem degradation of porcine articular cartilage.

Postmortem decompositional changes to articular cartilage were analysed to help establish a new methodology in determining the postmortem interval. The cartilage was collected from porcine trotters buried in simulated shallow graves for different time periods. The trotters were dissected to expose the cartilage located at the metatarsal joint. Numerous macroscopic changes including a colour change, gradual degradation of cartilage and adjacent soft tissues and a loss of cartilage covering articular facets were observed. Further analysis was conducted using light microscopy (LM) and scanning electron microscopy (SEM) to assess microstructural changes. Both LM and SEM showed gradual morphological and structural changes to the tissue over time, along with loss of nuclear material. Tissue surface analysis with SEM highlighted orthorhombic shaped crystals that appear at approximately three weeks postmortem and persist until six weeks postmortem. Both microscopic and macroscopic characteristics followed a recognisable succession over the burial times observed. These results indicate that postmortem degradation of articular cartilage may be useful for estimating a presumptive postmortem interval.

Identification of crystals forming on porcine articular cartilage: a new method for the estimation of the postmortem interval.

Articular cartilage was examined to determine its decomposition sequence and its potential for assessing the postmortem interval. Scanning electron microscopy of articular cartilage from buried porcine trotters showed the presence of microcrystals on the synovial surface. These orthorhombic pyramidal or “coffin”‐shaped crystals, appeared at 3 weeks (22 days) after interment and disappeared after 6 weeks. The disappearance of these crystals was linked to decompositional changes to the integrity of the synovial joint. The formation and disappearance of these crystals was associated with a pH change at the cartilage surface. Scanning electron microscopy–energy‐dispersive X‐ray (SEM‐EDX) analysis showed that the five main elements contained within these crystals were carbon, nitrogen, oxygen, magnesium, and phosphorous. Such elemental analysis suggested the crystals may be struvite (MgNH4PO46(H2O)). Bacteria cultured from the cartilage synovial surface produced struvite crystals when grown in suitable media and were identified by DNA analysis to be Comamonas sp.

Pore Sub‐Features Reproducibility in Direct Microscopic and Livescan Images—Their Reliability in Personal Identification

Abstract:  Third level features have been reported to have equal discriminatory power as second level details in establishing personal identification. Pore area, as an extended set third level sub‐feature, has been studied by minimizing possible factors that could affect pore size. The reproducibility of pore surface area has been studied using direct microscopic and 500 ppi Livescan images. Direct microscopic pore area measurements indicated that the day on which the pore area was measured had a significant impact on the measured pore area. Pore area measurement was shown to be difficult to estimate in 500 ppi Livescan measurements owing to lack of resolution. It is not possible to reliably use pore area as an identifying feature in fingerprint examination.

Preliminary analysis of the nature and processing of palm marks by a U.K. fingerprint bureau.

The nature of crime scene palmar images (CSPI) or factors affecting search parameters using a palm‐enabled AFIS system have not been investigated. A questionnaire‐based survey, undertaken by U.K. fingerprint experts utilizing the U.K.s IDENT‐1 system during the period January to July 2010, of CSPI marks has been conducted to provide descriptive statistical data on the nature of CSPI and some aspects of the ACE‐V process. 45 scene‐recovered marks were analyzed for part of the CSPI recovered, friction ridge detail, and process times. U.K. population handedness was different from recovered CSPI. Most and least frequently recovered regions were hypothenar pad B and the central pad, respectively. There was a nonsignificant association between palm region and number of palm regions recovered, as well as identification rate and analysis times and characteristics. The number of CSPI regions was significantly related to time for analysis, identification, and comparison.

DNA recovery from latent fingermarks treated with an infrared fluorescent fingerprint powder

The effect of the infrared fluorescent fingermark visualisation powder, fpNatural 1™, on the recovery of both the quantity and quality of touch DNA from fingerprints deposited on glass slides, was investigated using qPCR and STR typing. Four donors each deposited replicate marks, which were either left untreated (n=5) or treated by dusting with fpNatural 1™ (n=5). Each sample was swabbed using the double swab technique, before being extracted using the EZNA Forensic DNA kit and then DNA quantitated before being subjected to DNA profile analysis. Results showed that there was no significant effect of fpNatural 1™ on either the quantity or quality of recovered DNA. This suggests that fpNatural 1™ may prove a good choice of powder for regular use at crime scenes or in the laboratory. The fpNatural 1™ properties of low density, water immiscibility and low DNA affinity may account for these positive outcomes.

Investigating the Postmortem Molecular Biology of Cartilage and its Potential Forensic Applications

This study investigated the postmortem molecular changes that articular cartilage undergoes following burial. Fresh pig trotters were interred in 30‐cm‐deep graves at two distinct locations exhibiting dissimilar soil environments for up to 42 days. Extracts of the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joint cartilage from trotters disinterred weekly over 6 weeks were analyzed by Western blot against the monoclonal antibody 2‐B‐6 to assess aggrecan degradation. In both soil conditions, aggrecan degradation by‐products of decreasing molecular size and complexity were observed up to 21 days postmortem. Degradation products were undetected after this time and coincided with MCP/MTP joint exposure to the soil environment. These results show that cartilage proteoglycans undergo an ordered molecular breakdown, the analysis of which may have forensic applications. This model may prove useful for use as a human model and for forensic investigations concerning crimes against animals and the mortality of endangered species.

The Effect of Image Alterations on Identification Using Palmar Flexion Creases

Palmprints are identified using matching of minutia points, which can be time consuming for fingerprint experts and in database searches. This article analyzes the operational characteristics of a palmar flexion crease (PFC) identification software tool, using a dataset of 10 replicates of 100 palms, where the user can label and match palmar line features. Results show that 100 palmprint images modified 10 times each using rotation, translation, and additive noise, mimicking some of the characteristics found in crime scene palmar marks, can be identified with a 99.2% genuine acceptance rate and 0% false acceptance rate when labeled within 3.5 mm of the PFC. Partial palmprint images can also be identified using the same method to filter the dataset prior to traditional matching, while maintaining an effective genuine acceptance rate. The work shows that identification using PFCs can improve palmprint identification through integration with existing systems, and through dedicated palmprint identification applications.