Combination of off-line and on-line signature verification systems based on SVM and DST

The objective of this work is to present a signature verification system based on combination of off-line and online systems for managing conflict provided by the Support Vector Machine (SVM) classifiers. This system is basically divided into three parts: i) off-line verification stage, ii) on-line verification stage and iii) combination module using Dempster-Shafer theory (DST). The proposed framework allows combining the normalized SVM outputs and uses an estimation technique based on the dissonant model of Appriou to compute the belief assignments. Combination is performed using Dempster-Shafer (DS) rule followed by the likelihood ratio based decision making. Experiments are conducted on the well know NISDCC signature collection using false rejection and false acceptance criteria. The obtained results show that the proposed combination framework using DST yields the best verification accuracy compared to the sum rule even when individual off-line and on-line classifications provide conflicting results.