1. A method for displaying a real space image and a virtual space image, the method comprising the steps of: providing a pickup device at a position conjugate to eyes of an observer; picking up an image of real space by the pickup device to thereby provide a real space image wherein the real space image includes a plurality of first pixels, each of said first pixels representing a respective portion of the image of real space; obtaining a virtual space image based on virtual space information wherein the virtual space image includes a plurality of second pixels, each of said second pixels representing a respective portion of the virtual space information, wherein each individual one of said second pixels corresponds to a respective individual one of said first pixels; determining, for each one of said first pixels, a distance from the observer to a location in real space of the portion of the image of real space corresponding to the respective first pixel; and comparing, for each one of the first pixels, the distance from the observer to the location in real space corresponding to the respective first pixel with a distance from the observer to an apparent location in virtual space associated with the corresponding second pixel, and selecting whichever of the respective first pixel and the corresponding respective second pixel which corresponds to a location which is nearer to the observer in order to present a synthesized image of the virtual space image and the real space image to the observer.