Combining contact models with perceptual data reduction for efficient haptic data communication in networked VEs

In cooperative networked virtual environments, haptic rendering enables joint haptic interaction with virtual objects and, thus, shared touch experiences among multiple users. In case of an underlying packet-based communication network (e.g., the Internet), minimizing the end-to-end delay, with the goal of preventing instability of the involved control loops, results in high packet rates. Previously proposed perceptual data reduction approaches address this challenge and satisfy the strict delay constraints. However, significantly increased packet rates still occur during contact events. We present a novel event-based coding scheme based on a distributed haptic-rendering framework that integrates model-based distributed haptic rendering with perceptual data reduction. We also present a comprehensive haptic contact model for signals with multiple degrees of freedom. Furthermore, we show that the integration of event-triggered force transient models from event-based haptics into our local contact model is instrumental for generating convincing haptic feedback. Psychophysical experiments reveal that the approach presented herein allows us to push the data reduction performance beyond what is normally achievable by perceptual data reduction schemes alone while significantly improving the quality of haptic contact feedback.