A video combining apparatus to superimpose a virtual image such a CG image
on a video image of the real world or on a see-through type display
device. An area in which the virtual image is not to be displayed can be
easily designated by a user. If the user holds a frame with markers in
his/her sight, the frame is image-sensed in the video image of the real
world. The area designated by the user is detected by detecting the
position of the marker in the video image, and the virtual image is not
superimposed in this area.