ABSTRACT
This chapter examines the levels of fusion and the various scenarios that are possible in a multimodal biometric system. It discusses the different modes of operation, the integration strategies adopted to consolidate evidence, and issues related to the design and deployment of these systems. Biometrics, described as the science of recognizing an individual based on physiological or behavioral traits, is beginning to gain acceptance as a legitimate method of determining an individual’s identity. A multimodal system can operate in one of three different modes: serial mode, parallel mode, or hierarchical mode. In the serial mode of operation, the output of one modality is typically used to narrow down the number of possible identities before the next modality is used. The strategy adopted for integration depends on the level at which fusion is performed. Fusion at the feature level can be accomplished by concatenating two compatible feature sets.
