64 research outputs found
Genetic Programming for Multibiometrics
Biometric systems suffer from some drawbacks: a biometric system can provide
in general good performances except with some individuals as its performance
depends highly on the quality of the capture. One solution to solve some of
these problems is to use multibiometrics where different biometric systems are
combined together (multiple captures of the same biometric modality, multiple
feature extraction algorithms, multiple biometric modalities...). In this
paper, we are interested in score level fusion functions application (i.e., we
use a multibiometric authentication scheme which accept or deny the claimant
for using an application). In the state of the art, the weighted sum of scores
(which is a linear classifier) and the use of an SVM (which is a non linear
classifier) provided by different biometric systems provide one of the best
performances. We present a new method based on the use of genetic programming
giving similar or better performances (depending on the complexity of the
database). We derive a score fusion function by assembling some classical
primitives functions (+, *, -, ...). We have validated the proposed method on
three significant biometric benchmark datasets from the state of the art
Hybrid Template Update System for Unimodal Biometric Systems
Semi-supervised template update systems allow to automatically take into
account the intra-class variability of the biometric data over time. Such
systems can be inefficient by including too many impostor's samples or skipping
too many genuine's samples. In the first case, the biometric reference drifts
from the real biometric data and attracts more often impostors. In the second
case, the biometric reference does not evolve quickly enough and also
progressively drifts from the real biometric data. We propose a hybrid system
using several biometric sub-references in order to increase per- formance of
self-update systems by reducing the previously cited errors. The proposition is
validated for a keystroke- dynamics authentication system (this modality
suffers of high variability over time) on two consequent datasets from the
state of the art.Comment: IEEE International Conference on Biometrics: Theory, Applications and
Systems (BTAS 2012), Washington, District of Columbia, USA : France (2012
Performance Evaluation of Biometric Template Update
Template update allows to modify the biometric reference of a user while he
uses the biometric system. With such kind of mechanism we expect the biometric
system uses always an up to date representation of the user, by capturing his
intra-class (temporary or permanent) variability. Although several studies
exist in the literature, there is no commonly adopted evaluation scheme. This
does not ease the comparison of the different systems of the literature. In
this paper, we show that using different evaluation procedures can lead in
different, and contradictory, interpretations of the results. We use a
keystroke dynamics (which is a modality suffering of template ageing quickly)
template update system on a dataset consisting of height different sessions to
illustrate this point. Even if we do not answer to this problematic, it shows
that it is necessary to normalize the template update evaluation procedures.Comment: International Biometric Performance Testing Conference 2012,
Gaithersburg, MD, USA : United States (2012
Fast computation of the performance evaluation of biometric systems: application to multibiometric
The performance evaluation of biometric systems is a crucial step when
designing and evaluating such systems. The evaluation process uses the Equal
Error Rate (EER) metric proposed by the International Organization for
Standardization (ISO/IEC). The EER metric is a powerful metric which allows
easily comparing and evaluating biometric systems. However, the computation
time of the EER is, most of the time, very intensive. In this paper, we propose
a fast method which computes an approximated value of the EER. We illustrate
the benefit of the proposed method on two applications: the computing of non
parametric confidence intervals and the use of genetic algorithms to compute
the parameters of fusion functions. Experimental results show the superiority
of the proposed EER approximation method in term of computing time, and the
interest of its use to reduce the learning of parameters with genetic
algorithms. The proposed method opens new perspectives for the development of
secure multibiometrics systems by speeding up their computation time.Comment: Future Generation Computer Systems (2012
Web-Based Benchmark for Keystroke Dynamics Biometric Systems: A Statistical Analysis
Most keystroke dynamics studies have been evaluated using a specific kind of
dataset in which users type an imposed login and password. Moreover, these
studies are optimistics since most of them use different acquisition protocols,
private datasets, controlled environment, etc. In order to enhance the accuracy
of keystroke dynamics' performance, the main contribution of this paper is
twofold. First, we provide a new kind of dataset in which users have typed both
an imposed and a chosen pairs of logins and passwords. In addition, the
keystroke dynamics samples are collected in a web-based uncontrolled
environment (OS, keyboards, browser, etc.). Such kind of dataset is important
since it provides us more realistic results of keystroke dynamics' performance
in comparison to the literature (controlled environment, etc.). Second, we
present a statistical analysis of well known assertions such as the
relationship between performance and password size, impact of fusion schemes on
system overall performance, and others such as the relationship between
performance and entropy. We put into obviousness in this paper some new results
on keystroke dynamics in realistic conditions.Comment: The Eighth International Conference on Intelligent Information Hiding
and Multimedia Signal Processing (IIHMSP 2012), Piraeus : Greece (2012
Keystroke Dynamics Authentication For Collaborative Systems
We present in this paper a study on the ability and the benefits of using a
keystroke dynamics authentication method for collaborative systems.
Authentication is a challenging issue in order to guarantee the security of use
of collaborative systems during the access control step. Many solutions exist
in the state of the art such as the use of one time passwords or smart-cards.
We focus in this paper on biometric based solutions that do not necessitate any
additional sensor. Keystroke dynamics is an interesting solution as it uses
only the keyboard and is invisible for users. Many methods have been published
in this field. We make a comparative study of many of them considering the
operational constraints of use for collaborative systems
CNNs Fusion for Building Detection in Aerial Images for the Building Detection Challenge
published in CVPR workshop proceedingsThis paper presents our contribution to the DeepGlobe Building Detection Challenge. We enhanced the SpaceNet Challenge winning solution by proposing a new fusion strategy based on a deep combiner using segmentation both results of different CNN and input data to segment. Segmentation results for all cities have been significantly improved (between 1% improvement over the baseline for the smallest one to more than 7% for the largest one). The separation of adjacent buildings should be the next enhancement made to the solution
Evaluation of Biometric Authentication Systems through Visualisation of Partitioned and Bundled Power-graphs
International audienceBiometric authentication systems verify the identity of individuals based on what they are. As they are error prone, they can reject genuine individuals or accept impostors. Researchers of the field quantify the quality of their algorithm by benchmarking it on several databases. However, although the standard evaluation metrics state the performance of their system, they are unable to explain the reasons of their errors. This paper presents a novel way to visualize the evaluation results of a biometric authentication system which helps to find which individuals or samples are sources of errors. This knowledge could help to fix the algorithms. A biometric database of scores is modeled as a partitioned power-graph with nodes representing biometric samples and power-nodes representing individuals. A novel recursive edge bundling method is also applied to reduce clutter. This proposal has been successfully applied on several biometric databases and has proved its efficiency
Contributions à la dynamique de frappe au clavier : multibiométrie, biométrie douce et mise à jour de la référence
Keystroke dynamics is a behavioural biometry which allows to authenticate individuals through there way of typing on a keyboard. Such systems are cheap, as they do not need specific devices different from the keyboard of the computer. They are also well accepted by the user. We are mainly interested in static systems where the text typed by the user is known in advance by the machine. Sadly, the performance of this modality are rather mediocre because of the high variability of the biometric data which comes from emotional state of the individual, the learning of they way to type, ... In this thesis, we propose various contributions which allow to improve the recognition performance of keystroke dynamics systems. We also do an analysis of the public datasets allowing to evaluate the performance of new recognition systems. One contribution is the creation of a system which allows the authentication of users with a shared password. Then, we study the biometric fusion with face recognition and keystroke dynamics in order to increase the performance of the two systems. We show, on two different datasets, that it is possible to guess the gender of an individual through its way of typing to a keyboard. Finally, we present a new template update method which allows to take into account the ageing of the biometric data in order to not observe a decrease of performance overtime.La dynamique de frappe au clavier est une modalité biométrique comportementale qui permet d'authentifier des individus selon leur façon de taper au clavier. Un tel système est peu coûteux, car il ne nécessite pas de matériel d'acquisition autre que le clavier de l'ordinateur, et est facilement accepté par l'utilisateur. Nous nous sommes principalement intéressé aux systèmes statiques où le texte saisit par l'utilisateur est connu à l'avance par la machine. Malheureusement, les performances de cette modalité sont plutôt médiocres en raison de la forte variabilité de la donnée biométrique. Cette variabilité est due à l'état émotionnel de la personne, l'apprentissage de la façon de taper, \ldots Nous proposons dans cette thèse différentes contributions permettant d'améliorer les performances de reconnaissance de systèmes de dynamique de frappe au clavier (DDF). Nous effectuons également une analyse des bases publiques permettant d'évaluer la performance de nouveaux systèmes de reconnaissance. Une contribution est la mise au point d'un système de DDF par mot de passe partagé. Nous étudions ensuite la fusion multibiométrique avec la dynamique de frappe au clavier et la reconnaissance faciale afin d'augmenter les performances des deux systèmes. Nous montrons, sur deux jeux de données différents, qu'il est possible de reconnaitre le genre d'un individu suivant sa façon de taper au clavier. Enfin, nous présentons une nouvelle méthode de mise à jour de la référence biométrique qui permet de prendre en compte le vieillissement de la donnée biométrique, afin de ne pas avoir une diminution des performances de reconnaissance au cours du temps
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