A receiver measures strength of magnetic field generated by a transmitter and supplies it to a computer. The computer detects a viewpoint of a viewer based on the strength. The computer sets each pixel-displaying element arranged on the display portion of image display as a subject pixel-displaying element in turn. The computer obtains set pixel data from multiple items of pixel data constituting image data of one screen as pixel data corresponding to the subject pixel-displaying element. The image data has been obtained by a camera arranged for a position on an imaged plane corresponding to the split area in the display portion including the subject pixel-displaying element and stored in data storage. The set pixel data corresponds to a beam of light irradiated from the object along a straight line connecting the viewpoint and the subject pixel-displaying element. The computer supplies the set pixel data to a display.