Multimodal Biometrics -- Sources, Architecture and Fusion Techniques: An Overview

Biometrics is the science and technology of measuring and analyzing biological data of human body, extracting a feature set from the acquired data, and comparing this set against to the template set in the database. The increasing demand of enhanced security systems has led to an unprecedented interest in biometric based person authentication system. Biometric systems based on single source of information are called Unimodal systems. Although some Unimodal systems have got considerable improvement in reliability and accuracy, they often suffer from enrollment problems due to non-universal biometrics traits, susceptibility to biometric spoofing or insufficient accuracy caused by noisy data. Hence, single biometric may not be able to achieve the desired performance requirement in real world applications. One of the methods to overcome these problems is to make use of multimodal biometric authentication systems, which combine information from multiple modalities to arrive at a decision. Multimodal biometric systems are those which utilize, or capability of utilizing, more than one physiological or behavioral characteristic for enrollment, verification, or identification. Studies have demonstrated that multimodal biometric systems can achieve better performance compared with Unimodal systems. We discuss here different multimodal sources, multimodal architectures & different fusion techniques used in multimodal biometric systems.