IMAGE DISPLAYING SYSTEM AND IMAGE DISPLAYING METHOD

An image generation apparatus increases an adjustment amount of a luminance distribution to a target value B at a time t 0 at which an amount of light entering the eyes of a user changes to such a degree that the change has an influence on an action of photoreceptor cells, to thereby cause a head-mounted display to display an image 310 b having a luminance increased from that of an original image 310 a . The image generation apparatus gradually decreases the adjustment amount of the luminance distribution during a restoration period Δt in such a manner that an image 310 c having the original luminance distribution is displayed at a later time t 1.