Real-time generation of interactive virtual human behaviours

In this paper, we propose a new approach for generating interactive behaviours for virtual characters, namely the windowed Viterbi algorithm, capable of doing so in real-time. Consequently, we compare the performance of the standard Viterbi algorithm and the windowed Viterbi algorithm within our system. Our system tracks and analyses the behaviour of a real person in video input and produces a fully articulated three dimensional (3D) character interacting with the person in the video input. Our system is model-based. Prior to tracking, we train a collection of dual-input Hidden Markov Model (HMM) on 3D motion capture (MoCap) data representing a number of interactions between two people. Then using the dual-input HMM, we generate a moving virtual character reacting to (the motion of) a real person. In this article, we present the detailed evaluation of using the windowed Viterbi algorithms within our system, and show that our approach is suitable for generating interactive behaviours in real-time. Furthermore, in order to enhance the tracking capabilities of the algorithm, we develop a novel technique that splits the complex motion data in an automated way. This results in improved tracking of the human motion from our model.