On co-training online biometric classifiers
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Citations
Biometric quality: a review of fingerprint, iris, and face
Cooperative learning and its application to emotion recognition from speech
Learning discriminative binary codes for finger vein recognition
Improving cross-resolution face matching using ensemble-based co-transfer learning.
Face Image Quality Assessment: A Literature Survey
References
Incremental and Decremental Support Vector Machine Learning
Multi-PIE
Introduction to Semi-Supervised Learning
Bootstrapping
Related Papers (5)
Frequently Asked Questions (15)
Q2. What future works have the authors mentioned in the paper "On co-training online biometric classifiers" ?
As future work, the proposed framework can be extended to different stages of a biometric system that require regular updates. The authors also plan to incorporate the quality of the given gallery-probe pair in computing the confidence of prediction rather than making a decision based only on the distance from the hyperplane.
Q3. What is the purpose of the proposed framework?
In the proposed framework, co-training is used to leverage the availability of multiple classifiers and unlabeled instances to update the decision boundaries of both the classifiers and account for the wide intra-class variations introduced by the probe set.
Q4. What is the purpose of the proposed co-training framework?
During probe verification, whenever a user queries the system, co-training is used to update the classifiers using the unlabeled data.
Q5. How many instances were used for classifier update?
For online learning, during enrolment, classifier1 was updated using 22,145instances and classifier2 was updated using 31,846 instances.
Q6. What is the main reason for the change in the score distribution of a biometric system?
New enrolments can lead to variations in genuine and impostor score distributions while probe images may introduce wide intra-class variations (due to temporal changes).
Q7. What is the purpose of retraining a biometric system?
To maintain the performance and to accommodate the variations caused due to new enrolments and probes, biometric systems generally require re-training.
Q8. What is the advantage of online SVM classifiers?
online SVM classifiers have a significant advantage of reduced re-training time using only the new sample points to update the decision boundary.
Q9. What is the way to update a classifier?
Since corresponding labels (“genuine” or “impostor”) are available during enrolment, classifier update using online learning can be viewed as a supervised learning approach.∙ unlabeled information obtained at probe level can be used to update the classifier using co-training.
Q10. What is the mapping function used to map the data space to the feature space?
is the mapping function used to map the data space to the feature space, and 𝐶 is the tradeoff parameter between the permissible error in the samples and the margin.
Q11. How many users can use online learning algorithms?
Kim et al. [14] have shown that online learning algorithms can be used for biometric score fusion in order to resolve the computational problems with increasing number of users.
Q12. What is the process to update a classifier?
Iterate: 𝑗= 1 to number of views (number of classifiers) Process: Train classifier 𝑐𝑗 on 𝑗𝑡ℎ views of 𝐷𝐿 for 𝑘 = 1 to 𝑁 doPredict labels: 𝑐𝑗(𝑥𝑖,𝑗) → 𝑦𝑖 if 𝑦𝑖 ∕= 𝑧𝑖 thenUpdate 𝑐𝑗 with labeled instance {𝑥𝑖,𝑗 ,𝑧𝑖} end ifend for End iterate Output: Updated classifier 𝑐1 and 𝑐2.
Q13. How many instances were updated using co-training?
For the proposed framework, classifier1 was updated on 34, 086 instances and classifier2 was updated on 42, 102 instances using co-training during probe verification.
Q14. What is the way to train a classifier?
In co-training, as proposed by Blum and Mitchell [7], two classifiers that are trained on separate views (features), co-train each other based on their confidence in predicting the labels.
Q15. How many sample points can be controlled by co-training?
By varying the confidence threshold for a classifier, the number of sample points on which co-training is performed can be controlled.