Transmission of 3-D images by means of lens guides
Michel A. Duguay, Gary D. Aumiller · Applied Optics · 1979
A simple lens guide can be used to present to an observer a lifelike 3-D image of a distant object. The natural way in which the image is presented suggests the use of lens guides within buildings to look outside from interior rooms and in some applications now served by electronic closed-circuit television.