Multimodal user interfaces: who's the user?

A wide variety of systems require reliable personal recognition schemes to either confirm or determine the identity of an individual requesting their services. The purpose of such schemes is to ensure that only a legitimate user, and not anyone else, accesses the rendered services. Examples of such applications include secure access to buildings, computer systems, laptops, cellular phones and ATMs. Biometric recognition, or simply biometrics, refers to the automatic recognition of individuals based on their physiological and/or behavioral characteristics. By using biometrics it is possible to confirm or establish an individual's identity based on "who she is", rather than by "what she possesses" (e.g., an ID card) or "what she remembers" (e.g., a password). Current biometric systems make use of fingerprints, hand geometry, iris, face, voice, etc. to establish a person's identity. Biometric systems also introduce an aspect of user convenience. For example, they alleviate the need for a user to remember multiple passwords associated with different applications. A biometric system that uses a single biometric trait for recognition has to contend with problems related to non-universality of the trait, spoof attacks, limited degrees of freedom, large intra-class variability, and noisy data. Some of these problems can be addressed by integrating the evidence presented by multiple biometric traits of a user (e.g., face and iris). Such systems, known as multimodal biometric systems, demonstrate substantial improvement in recognition performance. In this talk, we will present various applications of biometrics, challenges associated in designing biometric systems, and various fusion strategies available to implement a multimodal biometric system.