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Träfflista för sökning "LAR1:hh srt2:(2005-2009);srt2:(2008);pers:(Alonso Fernandez Fernando)"

Sökning: LAR1:hh > (2005-2009) > (2008) > Alonso Fernandez Fernando

  • Resultat 1-7 av 7
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1.
  • Alonso-Fernandez, Fernando, et al. (författare)
  • Dealing With Sensor Interoperability in Multi-biometrics : The UPM Experience at the Biosecure Multimodal Evaluation 2007
  • 2008
  • Ingår i: Biometric Technology for Human Identification. - Bellingham, WA : SPIE - International Society for Optical Engineering. - 9780819471352 ; , s. J9440-J9440
  • Konferensbidrag (refereegranskat)abstract
    • Multimodal biometric systems allow to overcome some of the problems presented in unimodal systems, such as non-universality, lack of distinctiveness of the unimodal trait, noise in the acquired data, etc. Integration at the matching score level is the most common approach used due to the ease in combining the scores generated by different unimodal systems. Unfortunately, scores usually lie in application-dependent domains. In this work, we use linear logistic regression fusion, in which fused scores tend to be calibrated log-likelihood-ratios and thus, independent of the application. We use for our experiments the development set of scores of the DS2 Evaluation (Access Control Scenario) of the BioSecure Multimodal Evaluation Campaign, whose objective is to compare the performance of fusion algorithms when query biometric signals are originated from heterogeneous biometric devices. We compare a fusion scheme that uses linear logistic regression with a set of simple fusion rules. It is observed that the proposed fusion scheme outperforms all the simple fusion rules, with the additional advantage of the application-independent nature of the resulting fused scores.
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2.
  • Alonso-Fernandez, Fernando, et al. (författare)
  • Fingerprint Databases and Evaluation
  • 2008. - 1
  • Ingår i: Encyclopedia of Biometrics. - New York : Springer-Verlag New York. - 9780387730035 ; , s. 452-458
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)
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3.
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4.
  • Fronthaler, Hartwig, et al. (författare)
  • Fingerprint Image-Quality Estimation and its Application to Multialgorithm Verification
  • 2008
  • Ingår i: IEEE Transactions on Information Forensics and Security. - New York, N.Y. : IEEE Signal Processing Society. - 1556-6013 .- 1556-6021. ; 3:2, s. 331-338
  • Tidskriftsartikel (refereegranskat)abstract
    • Signal-quality awareness has been found to increase recognition rates and to support decisions in multisensor environments significantly. Nevertheless, automatic quality assessment is still an open issue. Here, we study the orientation tensor of fingerprint images to quantify signal impairments, such as noise, lack of structure, blur, with the help of symmetry descriptors. A strongly reduced reference is especially favorable in biometrics, but less information is not sufficient for the approach. This is also supported by numerous experiments involving a simpler quality estimator, a trained method (NFIQ), as well as the human perception of fingerprint quality on several public databases. Furthermore, quality measurements are extensively reused to adapt fusion parameters in a monomodal multialgorithm fingerprint recognition environment. In this study, several trained and nontrained score-level fusion schemes are investigated. A Bayes-based strategy for incorporating experts' past performances and current quality conditions, a novel cascaded scheme for computational efficiency, besides simple fusion rules, is presented. The quantitative results favor quality awareness under all aspects, boosting recognition rates and fusing differently skilled experts efficiently as well as effectively (by training).
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5.
  • Gilperez, A., et al. (författare)
  • Off-line Signature Verification Using Contour Features
  • 2008
  • Ingår i: Proceedings. - Montréal : CENPARMI, Concordia University. - 9781895193039
  • Konferensbidrag (refereegranskat)abstract
    • An off-line signature verification system based on contour features is presented. It works at the local image level, and encodes directional properties of signature contours and the length of regions enclosed inside letters. Results obtained on a sub-corpus of the MCYT signature database shows that directional-based features work much better than length-based features. Results are comparable to existing approaches based on different features. It is also observed that combination of the proposed features does not provide improvements in performance, maybe to some existing correlation among them.
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6.
  • Ruiz-Albacete, V., et al. (författare)
  • Direct attacks using fake images in iris verification
  • 2008
  • Ingår i: Biometrics and Identity Management. - Berlin : Springer Berlin/Heidelberg. - 9783540899907 ; , s. 181-190
  • Konferensbidrag (refereegranskat)abstract
    • In this contribution, the vulnerabilities of iris-based recognition systems to direct attacks are studied. A database of fake iris images has been created from real iris of the BioSec baseline database. Iris images are printed using a commercial printer and then, presented at the iris sensor. We use for our experiments a publicly available iris recognition system, which some modifications to improve the iris segmentation step. Based on results achieved on different operational scenarios, we show that the system is vulnerable to direct attacks, pointing out the importance of having countermeasures against this type of fraudulent actions. © 2008 Springer Berlin Heidelberg.
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7.
  • Tome, P., et al. (författare)
  • On the effects of time variability in iris recognition
  • 2008
  • Ingår i: BTAS 2008. 2nd IEEE International Conference on Biometrics. - Piscataway, N.J. : IEEE Press. - 9781424427307 ; , s. 411-416
  • Konferensbidrag (refereegranskat)abstract
    • In this paper, we evaluate the effects of time separation between acquisitions in iris recognition. We use for our experiments a publicly available iris recognition system and the BiosecurlD database, containing 8128 iris images of 254 individuals acquired in four acquisition sessions, separated by one to four weeks between consecutive sessions. Reported results show that time separation between iris samples under comparison has severe impact on the recognition rates. An important degradation on the False Rejection Rate is observed, meaning that the intra-class variability is increased. All images in our database have been acquired under similar controlled conditions and with the same sensor. © 2008 IEEE.
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  • Resultat 1-7 av 7

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