Human brain is one of the most adaptable systems in the world. Understanding the brain functions is one of the most important issues for evaluating and designing things around us to improve the quality of life. We investigate the brain through visual functions to apply the knowledge to ergonomics and image engineering. Our approaches include psychophysics, brain activity measurements, and computer simulations. Our research field covers visual spatial perception, 3D perception and visual attention. Modeling the processes of human vision based on the findings of the strategies that the visual system uses, we plan to propose appropriate methods for evaluation of image qualities, efficient way of image presentation and evaluation of visual environments in general. We also investigate dynamic selection process in vision with or without attention to realize prediction system of human perception and action. For predicting visual performance, which changes dynamically dependently on the stimulus and environment, we combine studies of human visual psychophysics, brain imaging, and computer modeling.