Multimodal biometrics: state of the art in fusion techniques

The concept of multimodal biometrics is gaining importance to realise reliable, accurate and robust authentication systems. In multimodal biometrics, information fusion can be done at various levels: sensor level, feature level, match-score level, rank level and decision level. This paper surveys the issues of fusion at different levels and recent researches addressing these issues. Furthermore, there are several fusion rules available to combine biometric traits at different levels of fusion. We have reviewed the recent approaches of fusion rules. A comparison of the state-of-the-art fusion techniques has been made to comprehend their merits and demerits.