Autostereograms

Introduction

  In a two dimensional plane, artists are able to create perceptions of depth, using perspective, shadows, color and intensity effects, hazing, and changes in size.  In three dimensions, we use “stereopsis” to render the effect of depth.  What is stereopsis?  Each eye captures a different view of an object since the eyes are separated.  The angular difference varies with the distance from the object.  Because of the disparity, when we focus our eyes on the object our retinas receive slightly different images.  The fusing of the two eyes’ images gives a “3-D” effect, and this process is known as “stereopsis”. 

Intuitively, we can use red/green filters or polarizers to split a single picture into two to give each eye a separate view.  These “traditional” ways of rendering 3D requires special viewing aid, such as polarizing glasses.  However, autostereograms do not require such viewing equipment – all that is required is to diverge ones eyes and some practice.