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.