Occurrence and associative value of non-identifiable fingermarks

Fingermarks that have insufficient characteristics for identification often have discernible characteristics that could form the basis for lesser degrees of correspondence or probability of occurrence within a population. Currently, those latent prints that experts judge to be insufficient for identification are not used as associative evidence. How often do such prints occur and what is their potential value for association? The answers are important. We could be routinely setting aside a very important source of associative evidence, with high potential impact, in many cases; or such prints might be of very low utility, adding very little, or only very rarely contributing to cases in a meaningful way. The first step is to better understand the occurrence and range of associative value of these fingermarks. The project goal was to explore and test a theory that in large numbers of cases fingermarks of no value for identification purposes occur and are readily available, though not used, and yet have associative value that could provide useful information. Latent fingermarks were collected from nine state and local jurisdictions. Fingermarks included were those (1) collected in the course of investigations using existing jurisdictional procedures, (2) originally assessed by the laboratory as of no value for identification (NVID), (3) re-assessed by expert review as NVID, but with least three clear and reliable minutiae in relationship to one another, and (4) determined to show at least three auto-encoded minutiae. An expected associative value (ESLR) for each mark was measured, without reference to a putative source, based on modeling within-variability and between-variability of AFIS scores. This method incorporated (1) latest generation feature extraction, (2) a (minutiae-only) matcher, (3) a validated distortion model, and (4) NIST SD27 database calibration. Observed associative value distributions were determined for violent crimes, property crimes, and for existing objective measurements of latent print quality. 750 Non Identifiable Fingermarks (NIFMs) showed values of Log10 ESLR ranging from 1.05 to 10.88, with a mean value of 5.56 (s.d. 2.29), corresponding to an ESLR of approximately 380,000. It is clear that there are large numbers of cases where NIFMs occur that have high potential associative value as indicated by the ESLR. These NIFMs are readily available, but not used, yet have associative value that could provide useful information. These findings lead to the follow-on questions, “How useful would NIFM evidence be in actual practice?” and, “What developments or improvements are needed to maximize this contribution?

Blending techniques for underwater photomosaics

The creation of consistent underwater photomosaics is typically hampered by local misalignments and inhomogeneous illumination of the image frames, which introduce visible seams that complicate post processing of the mosaics for object recognition and shape extraction. In this thesis, methods are proposed to improve blending techniques for underwater photomosaics and the results are compared with traditional methods. Five specific techniques drawn from various areas of image processing, computer vision, and computer graphics have been tested: illumination correction based on the median mosaic, thin plate spline warping, perspective warping, graph-cut applied in the gradient domain and in the wavelet domain. A combination of the first two methods yields globally homogeneous underwater photomosaics with preserved continuous features. Further improvements are obtained with the graph-cut technique applied in the spatial domain

Facilitating sensor interoperability and incorporating quality in fingerprint matching systems

This thesis addresses the issues of sensor interoperability and quality in the context of fingerprints and makes a three-fold contribution. The first contribution is a method to facilitate fingerprint sensor interoperability that involves the comparison of fingerprint images originating from multiple sensors. The proposed technique models the relationship between images acquired by two different sensors using a Thin Plate Spline (TPS) function. Such a calibration model is observed to enhance the inter-sensor matching performance on the MSU dataset containing images from optical and capacitive sensors. Experiments indicate that the proposed calibration scheme improves the inter-sensor Genuine Accept Rate (GAR) by 35% to 40% at a False Accept Rate (FAR) of 0.01%. The second contribution is a technique to incorporate the local image quality information in the fingerprint matching process. Experiments on the FVC 2002 and 2004 databases suggest the potential of this scheme to improve the matching performance of a generic fingerprint recognition system. The final contribution of this thesis is a method for classifying fingerprint images into 3 categories: good, dry and smudged. Such a categorization would assist in invoking different image processing or matching schemes based on the nature of the input fingerprint image. A classification rate of 97.45% is obtained on a subset of the FVC 2004 DB1 database

An evaluation of the mechanisms of recovery of DNA and fingerprints from fire scenes

Incidents involving the intentional or deliberate setting of a fire within a compartment are frequently difficult to investigate both because of the damage to the property in question and the apparent lack of forensic evidence which could be used to potentially identify a suspect. The recovery of such evidence in the form of DNA and fingerprints from a fire scene would therefore be advantageous. During this project, replicate samples of DNA and fingerprints were deposited on both porous and non porous surfaces which were then exposed to laboratory controlled elevated temperatures for various time periods. In each case replicate DNA samples or replicate depleted series of fingerprint samples were used to produce robust data sets for subsequent statistical analysis. DNA and fingerprint samples were also exposed to a real fire environment using a fire training facility in order to simulate operational conditions. The results obtained suggest that the optimum recovery method for low template DNA was to use a wet followed by a dry cotton swabbing action of the surface before combining the two swabs for extraction. When the DNA was exposed to elevated temperatures in a controlled environment, there was a greater possibility of recovering a full SGM Plus profile if the DNA had been absorbed into a porous rather than non porous surface and the surface exposed up to a maximum of 100˚C only. All of the samples which were exposed to the uncontrollable fire environment produced partial DNA profiles. The survivability and chemical enhancement of fingerprints deposited on both porous and non porous surfaces was robustly investigated where 70 replicate fingerprints were examined in each case for each test condition. For porous surfaces the most efficient sequence of enhancement techniques was an initial visual examination, followed by a fluorescence examination prior to treatment with DFO, and finally PD. It was found that this sequence could be employed for both wet and dry articles. In the case of dry, non porous surfaces, visual examination followed by fluorescence examination should be utilised prior to undertaking superglue - BY40 treatment. Powder suspension should be substituted for superglue in the case of wet items.Incidents involving the intentional or deliberate setting of a fire within a compartment are frequently difficult to investigate both because of the damage to the property in question and the apparent lack of forensic evidence which could be used to potentially identify a suspect. The recovery of such evidence in the form of DNA and fingerprints from a fire scene would therefore be advantageous. During this project, replicate samples of DNA and fingerprints were deposited on both porous and non porous surfaces which were then exposed to laboratory controlled elevated temperatures for various time periods. In each case replicate DNA samples or replicate depleted series of fingerprint samples were used to produce robust data sets for subsequent statistical analysis. DNA and fingerprint samples were also exposed to a real fire environment using a fire training facility in order to simulate operational conditions. The results obtained suggest that the optimum recovery method for low template DNA was to use a wet followed by a dry cotton swabbing action of the surface before combining the two swabs for extraction. When the DNA was exposed to elevated temperatures in a controlled environment, there was a greater possibility of recovering a full SGM Plus profile if the DNA had been absorbed into a porous rather than non porous surface and the surface exposed up to a maximum of 100˚C only. All of the samples which were exposed to the uncontrollable fire environment produced partial DNA profiles. The survivability and chemical enhancement of fingerprints deposited on both porous and non porous surfaces was robustly investigated where 70 replicate fingerprints were examined in each case for each test condition. For porous surfaces the most efficient sequence of enhancement techniques was an initial visual examination, followed by a fluorescence examination prior to treatment with DFO, and finally PD. It was found that this sequence could be employed for both wet and dry articles. In the case of dry, non porous surfaces, visual examination followed by fluorescence examination should be utilised prior to undertaking superglue - BY40 treatment. Powder suspension should be substituted for superglue in the case of wet items

OCT en phase pour la reconnaissance biométrique par empreintes digitales et sa sécurisation

In an increasingly open world, the flows of people are brought to explode in the coming years. Facilitating, streamlining, and managing these flows, by maintaining strict security constraints, therefore represent a key element for the global socio-economic dynamism. This flows management is mainly based on knowledge and verification of person identity. For its practicality and a priori secured, biometrics, in particular fingerprints biometrics, has become an effective and unavoidable solution.Nevertheless, it still suffers from two severe limitations. The first one concerns the poor performances obtained with damaged fingers. This damage can be involuntary (e.g. manual workers) or volunteers, for purposes of anonymity. The second limitation consists in the vulnerability of the commonly used sensors. In particular, they are vulnerable to copies of stolen fingerprints, made by malicious persons for identity theft purpose. We believe that these limitations are due to the small amount of information brought by the usual biometric sensors. It often consists in a single print of the finger surface. However, the biological complexity of human tissue provides rich information, unique to each person, and very difficult to reproduce. We therefore proposed an imaging approach based on Optical Coherence Tomography (OCT), a 3D contactless optical sensor, to finely measure this information. The main idea of the thesis is therefore to explore novel ways to exploit this information in order to make biometrics more robust and truly secured. In particular, we have proposed and evaluated different fingerprint imaging methods, based on the phase of the OCT signalDans un monde de plus en plus ouvert, les flux de personnes sont amenés à exploser dans les prochaines années. Fluidifier et contrôler ces flux, tout en respectant de fortes contraintes sécuritaires, apparaît donc comme un élément clef pour favoriser le dynamisme économique mondial. Cette gestion des flux passe principalement par la connaissance et la vérification de l’identité des personnes. Pour son aspect pratique et a priori sécurisé, la biométrie, et en particulier celle des empreintes digitales, s’est imposée comme une solution efficace, et incontournable. Néanmoins, elle souffre de deux sévères limitations. La première concerne les mauvaises performances obtenues avec des doigts détériorés. Ces détériorations peuvent être involontaires (travailleurs manuels par exemple), ou bien volontaires, à des fins d’anonymisation. La deuxième concerne les failles de sécurité des capteurs. En particulier, ils sont vulnérables à des attaques avec de fausses empreintes, réalisées par des personnes mal intentionnées dans un but d’usurpation d’identité. D’après nous, ces limitations sont dues à la faible quantité d’information exploitée par les capteurs usuels. Elle se résume souvent à une simple image de la surface du doigt. Pourtant, la complexité biologique des tissus humains est telle qu’elle offre une information très riche, unique, et difficilement reproductible. Nous avons donc proposé une approche d’imagerie, basée sur la Tomographique par Cohérence Optique, un capteur 3D sans contact, permettant de mesurer finement cette information. L’idée majeure de la thèse consiste à étudier divers moyens de l’exploiter, afin de rendre la biométrie plus robuste et vraiment sécurisé