Effects of lighting CCT and illuminance on visual perception and task performance in immersive virtual environments

In recent decades, immersive virtual environments (IVEs) have enabled users to experience various lighting scenarios with a high sense of presence and immersion, thereby having the potential to simulate office lighting design. To realistically experience lighting design cases in IVE lighting simulations, the CCT and illuminance levels should be accurately reproduced. However, there is still a lack of empirical evidence considering these factors. Thus, this study examined whether CCT and illuminance levels could be accurately reflected in IVE lighting simulations by investigating users' responses to variations in CCT and illuminance levels in IVEs. To this end, we created nine IVE lighting cases and investigated the responses of participants regarding visual perception (comfort, naturalness, dimness, and warmness) and task performance measured through a questionnaire and the Landolt C test. The results indicated that, although using head-mounted displays affected the perception of visual comfort in some respects, the participants showed responses corresponding to the general findings of field lighting simulations of previous studies. In terms of task performance, participants showed improvement as the illuminance increased in IVEs, while there was no specific relationship between CCT and task performance due to the different effects of CCT on visual acuity and contrast sensitivity. The present study empirically identified the potential of IVE lighting simulations considering CCT and illuminance. With further investigations on more diverse office lighting conditions, IVE lighting simulations will help architects design optimal office lighting.