| 1. |
- Alonso-Fernandez, Fernando, 1978-, et al.
(författare)
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A Comparative Study of Fingerprint Image-Quality Estimation Methods
- 2007
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Ingår i: IEEE Transactions on Information Forensics and Security. - New York : IEEE Press. - 1556-6013 .- 1556-6021. ; 2:4, s. 734-743
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Tidskriftsartikel (refereegranskat)abstract
- One of the open issues in fingerprint verification is the lack of robustness against image-quality degradation. Poor-quality images result in spurious and missing features, thus degrading the performance of the overall system. Therefore, it is important for a fingerprint recognition system to estimate the quality and validity of the captured fingerprint images. In this work, we review existing approaches for fingerprint image-quality estimation, including the rationale behind the published measures and visual examples showing their behavior under different quality conditions. We have also tested a selection of fingerprint image-quality estimation algorithms. For the experiments, we employ the BioSec multimodal baseline corpus, which includes 19 200 fingerprint images from 200 individuals acquired in two sessions with three different sensors. The behavior of the selected quality measures is compared, showing high correlation between them in most cases. The effect of low-quality samples in the verification performance is also studied for a widely available minutiae-based fingerprint matching system.
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| 2. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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An enhanced Gabor filter-based segmentation algorithm for fingerprint recognition systems
- 2005
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Konferensbidrag (refereegranskat)abstract
- An imponant step in fingerprint recognition is the segmentation of the region of interest. In this paper, we present an enhanced approach for fingerprint segmentation based on the response of eight oriented Gabor filters. The performance of the algorithm has been evaluated in terms of decision error trade-off curves of an overall verification system. Experimental results demonstrate the robustness of the proposed method.
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| 3. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Automatic Measures for Predicting Performance in Off-line Signature
- 2007
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Konferensbidrag (refereegranskat)abstract
- Performance in terms of accuracy is one of the most important goal of a biometric system. Hence, having a measure which is able to predict the performance with respect to a particular sample of interest is specially useful, and can be exploited in a number of ways. In this paper, we present two automatic measures for predicting the performance in off-line signature verification. Results obtained on a sub-corpus of the MCYT signature database confirms a relationship between the proposed measures and system error rates measured in terms of Equal Error Rate (EER), False Acceptance Rate (FAR) and False Rejection Rate (FRR). © 2007 IEEE.
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| 4. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Comparison of fingerprint quality measures using an optical and a capacitive sensor
- 2007
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Ingår i: Biometrics: Theory, Applications, and Systems, 2007. BTAS 2007. First IEEE International Conference on. - Piscataway, N.J. : IEEE Press. - 9781424415977 - 9781424415960 ; , s. 133-138
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Konferensbidrag (refereegranskat)abstract
- Although several image quality measures have been proposed for fingerprints, no work has taken into account the differences among capture devices, and how these differences impact on the image quality. In this paper, several representative measures for assessing the quality fingerprint images are compared using an optical and a capacitive sensor. The capability to discriminate between images of different quality and its relationship with the verification performance is studied. We report differences depending on the sensor, and interesting relationships between sensor technology and features used for quality assessment are also pointed out. ©2007 IEEE.
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| 5. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Dealing With Sensor Interoperability in Multi-biometrics : The UPM Experience at the Biosecure Multimodal Evaluation 2007
- 2008
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Ingår i: Biometric Technology for Human Identification. - Bellingham, WA : SPIE - International Society for Optical Engineering. - 9780819471352 ; , s. J9440-J9440
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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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| 6. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Fusion of static image and dynamic information for signature verification
- 2009
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Ingår i: ICIP 2009. - Piscataway, N.J. : IEEE Press. - 9781424456543 ; , s. 2725-2728
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Konferensbidrag (refereegranskat)abstract
- This paper evaluates the combination of static image (off-line) and dynamic information (on-line) for signature verification. Two off-line and two on-line recognition approaches exploiting information at the global and local levels are used. Experimental results are given using the BiosecurID database (130 signers, 3,640 signatures). Fusion experiments are done using a trained fusion approach based on linear logistic regression. It is shown experimentally that the local systems outperform the global ones, both in the on-line and in the off-line case. We also observe a considerable improvement when combining the two on-line systems, which is not the case with the off-line systems. The best performance is obtained when fusing all the systems together, which is specially evident for skilled forgeries when enough training data is available. ©2009 IEEE.
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| 7. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Impact of signature legibility and signature type in off-line signature verification
- 2007
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Ingår i: Biometrics Symposium, 2007. - Piscataway, N.J. : IEEE Press. - 9781424415496 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- The performance of two popular approaches for off-line signature nature verification in terms of signature legibility and signature type is studied. We investigate experimentally if the knowledge of letters, syllables or name instances can help in the process of imitating a signature. Experimental results are given on a sub-corpus of the MCYT signature database for random and skilled forgeries. We use for our experiments two machine experts, one based on global image analysis and statistical distance measures, and the second based on local image analysis and Hidden Markov Models. Verification results are reported in terms of Equal Error Rate (EER), False Acceptance Rate (FAR) and False Rejection Rate (FRR). ©2007 IEEE.
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| 8. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Impact of time variability in off-line writer identification and verification
- 2009
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Ingår i: ISPA 2009. - Piscataway, N.J. : IEEE Press. ; , s. 540-545
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Konferensbidrag (refereegranskat)abstract
- One of the biggest challenges in person recognition using biometric systems is the variability in the acquired data. In this paper, we evaluate the effects of an increasing time lapse between reference and test biometric data consisting of static images of handwritten signatures and texts. We use for our experiments two recognition approaches exploiting information at the global and local levels, and the BiosecurlD database, containing 3,724 signature images and 532 texts of 133 individuals acquired in four acquisition sessions distributed along a 4 months time span. We report results of the recognition systems working both in verification (one-to-one) and identification (one-to-many) mode. The results show the extent of the impact that the time separation between samples under comparison has on the recognition rates, being the local approach more robust to the time lapse than the global one. We also observe in our experiments that recognition based on handwritten texts provides higher accuracy than recognition based on signatures.
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| 9. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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Iris Recognition Based on SIFT Features
- 2009
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Ingår i: 2009 First IEEE International Conference on Biometrics, Identity and Securit. - 9781424452767 ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- Biometric methods based on iris images are believed to allow very high accuracy, and there has been an explosion of interest in iris biometrics in recent years. In this paper, we use the Scale Invariant Feature Transformation (SIFT) for recognition using iris images. Contrarily to traditional iris recognition systems, the SIFT approach does not rely on the transformation of the iris pattern to polar coordinates or on highly accurate segmentation, allowing less constrained image acquisition conditions. We extract characteristic SIFT feature points in scale space and perform matching based on the texture information around the feature points using the SIFT operator. Experiments are done using the BioSec multimodal database, which includes 3,200 iris images from 200 individuals acquired in two different sessions. We contribute with the analysis of the influence of different SIFT parameters on the recognition performance. We also show the complementarity between the SIFT approach and a popular matching approach based on transformation to polar coordinates and Log-Gabor wavelets. The combination of the two approaches achieves significantly better performance than either of the individual schemes, with a performance improvement of 24% in the Equal Error Rate.
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| 10. |
- Alonso-Fernandez, Fernando, et al.
(författare)
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On-line signature verification using Tablet PC
- 2005
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Ingår i: Proceedings of the 4th International Symposium on Image and Signal Processing and Analysis. - Zagreb : University of Zagreb. - 9789531840897 - 953184089X ; , s. 245-250
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Konferensbidrag (refereegranskat)abstract
- On-line signature verification for Tablet PC devices is studied. The on-line signature verification algorithm presented by the authors at the First International Signature Verification Competition (SVC 2004) is adapted to work in Tablet PC environments. An example prototype of securing access and securing document application using this Tablet PC system is also reported. Two different commercial Tablet PCs are evaluated, including information of interest for signature verification systems such as sampling and pressure statistics. Authentication performance experiments are reported considering both random and skilled forgeries by using a new database with over 3000 signatures.
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