A metric to quantify virtual scene movement for the study of cybersickness: Definition, implementation, and verification

This paper presents a metric to quantify visual scene movement perceived in side a virtual environment (VE) and illustrates how this method could be us ed in future studies to determine a cybersickness dose value to predict lev els of cybersickness in VEs. Sensory conflict theories predict that cybersi ckness produced by a VE is a kind of visually induced motion sickness. A co mprehensive review indicates that there is only one subjective measure to q uantify visual stimuli presented inside a VE. A metric, referred to as spat ial velocity (SV), is proposed. It combines objective measures of scene com plexity and scene movement velocity. The theoretical basis for the proposed SV metric and the algorithms for its implementation are presented. Data fr om two previous experiments on cybersickness were reanalyzed using the metr ic. Results showed that increasing SV by either increasing the scene comple xity or scene velocity significantly increased the rated level of cybersick ness. A strong correlation between SV and the level of cybersickness was fo und. The use of the spatial velocity metric to predict levels of cybersickn ess is also discussed.