Multim odal Speaker Detect ion Us ing I nput/Output Dynamic Bayesian Networks

Inferring users' actions and intentions forms an integral part of design and development of any human-computer interface. The presence of noisy and at times ambiguous sensory data makes this problem challenging. We formulate a framework for temporal fusion of multiple sensors using input-output dynamic Bayesian networks (IODBNs). We find that contextual information about the state of the computer interface, used as an input to the DBN, and sensor distributions learned from data are crucial for good detection performance. Nevertheless, clas- sical DBN learning methods can cause such models to fail when the data exhibits complex behavior. To further improve the detection rate we formulate an error- feedback learning strategy for DBNs. We apply this framework to the problem of audio/visual speaker detection in an interactive kiosk application using "off- the-shelf" visual and audio sensors (face, skin, texture, mouth motion, and silence detectors). Detection results obtained in this setup demonstrate numerous benefits of our learning-based framework.