AR-SSVEP for brain-machine interface: Estimating user's gaze in head-mounted display with USB camera

We aim to develop a brain-machine interface (BMI) system that estimates user's gaze or attention on an object to pick it up in the real world. In Experiment 1 and 2 we measured steady-state visual evoked potential (SSVEP) using luminance and/or contrast modulated flickers of photographic scenes presented on a head-mounted display (HMD). We applied multiclass SVM to estimate gaze locations for every 2s time-window data, and obtained significantly good classifications of gaze locations with the leave-one-session-out cross validation. In Experiment 3 we measured SSVEP using luminance and contrast modulated flickers of real scenes that were online captured by a USB camera and presented on the HMD. We put AR markers on real objects and made their locations flickering on HMD. We obtained the best performance of gaze classification with highest luminance and contrast modulation (73-91% accuracy at chance level 33%), and significantly good classification with low (25% of the highest) luminance and contrast modulation (42-50% accuracy). These results suggest that the luminance-modulated flickers of real scenes through USB camera can be applied to BMI by using augmented reality technology.