2016 年 18 巻 4 号 p. 353-362
We propose a new method for a car driver to help maintain alertness, which is based on a visual feedback of point of gaze (POG) and arousal level. History of horizontal and vertical POG (hvPOG) or horizontal POG (hPOG) is presented using position, brightness and color of visual stimuli. The color is determined by arousal level estimated with percentage of eye closure (PERCLOS). In order to evaluate the effect of the proposed method time courses of PERCLOS, reaction time to a visual target and subjective sleepiness during viewing a car driving movie were investigated for 9 subjects in conditions with a visual feedback of hvPOG (FB1) and hPOG (FB2), and without any feedback (control). Mean PERCLOS for 9 subjects tended to increase with time in all three conditions. The PERCLOS significantly exceeded the value of 5% for 10 out of 20 minutes in control condition, while that was not the case in FB1 and FB2 condition. Compared with the control condition, mean reaction time was significantly shorter (FB1:714 [ms], FB2:713 [ms] and control:804 [ms]) and the subjects reported weaker sleepiness in FB1 and FB2. These results show that the proposed method is effective to extend alertness.