Introduction

People always wanted to view three-dimensional images with no loss of information. This idea is not just for fun, but also for serious purposes: scientific visualisation, 3D-constructing of buildings and tools and so on.

• How three-dimensional-viewing works [CLAU 1994]
  Long ago, researchers found out that our two eyes which receive two slightly different images are the basis for three-dimensional viewing. Our brain manages to compute one picture with depth-impression from those two images. (We will use the term "image" when speaking of plain pictures and the term "picture" when speaking of the brain-generated-three-dimensional-impression.)
• Methods for simulating three-dimensional-pictures [CLAU 1994]
  Making use of this knowledge, people invented devices that use time-division-multiplexing for displaying those two pictures. Examples for this idea are Shutter-Glasses or Rotating-Mirror-Viewers. The next approch was the usage of Red-Green-Glasses or Polarisation-Glasses to put two images into one picture. The glasses managed the correct selection: one image for each eye.
• Autostereograms-the new approach [THIM 1994]
  The last great step was the elimination of any technical devices: Autostereograms. Autostereograms put two images together in one picture in a way that you can view the three-dimensional-scene just by concentrating on the picture.

These three major topics will be discussed in the following on the basis of [CLAU 1994], [THIM 1994] and [INGL 1994], followed by examples for both major types of Autostereograms (SIS and SIRDS). In the Appendix we give an overview of interesting books and Internet adresses.