A distance information generator comprises an image sensor which senses an
object, a distance detector which detects a first distance between a
predetermined position and the object, a memory which stores position
information expressing a mutual positional relationship of the
predetermined position and the position of the image sensor, and a
calculator which calculates a second distance between the position of the
image sensor and the object based on the first distance and the position
information. A display device displays a composite image which consists of
a sensed image and a virtual image for an observer, wherein the composite
image is created by comparing the second distance and distance information
involved in the virtual image.