Stereo Viewing (Introduction)

How Do We See Stereo?

For viewing stereo we need both of our eyes. Our brain finally combines the simultaneous images of our eyes to a 3d-impression.

The reason for being able to view stereo is the fact that the two eyes have a different position, their distance between is the stereo base of the eyes. So, the eyes have a different point of view. When focusing to the same point, the lines of sight of left and right image are different, they intersect at the point of interest in an intersecting angle, also called parallax. Nearer points have a bigger parallax than farer ones. This parallax gives us the experience of 3d-viewing.

What Does This Mean For Stereoscopy?

For creating stereograms (stereopair), we need to adopt our eyes capabilities for stereo viewing.

Capturing Stereograms

For capturing stereograms, we emulate our eyes, our viewing. Our eyes build a mainly horizontal base and our eyes look parallel and vertical to tha base (generally when looking far). This consequently is the main principle for taking stereograms.
Another aspect is taking moving scenery synchronously.

Representing and Viewing Stereograms

For reaching the 3d-experience of the stereogram, you need to see each of the images only with the corresponding eye: the left captured image with the left eye, the right captured image with the right eye.
There exist various methods to present stereograms – analog and dgital ones as well as methods with separate images or with overlapped/combinded presentations. Some are giving true colours, others influence or reduce the captured colours. Most methods need utilities for stereo viewing.

 
stereogram of a minox dcc 5.1 camera in three presentation modes
stereopair – red-cyan anaglyphs: coloured & monochrom

Not all will be mentioned here, but for viewing Mindscapers Stereo Gallery, especially the following methods are mentioned:

• Anaglyphs, e.g. red-cyan, red-green, yellow-blue, need Anaglyph stereo glasses – overlapped images, for printing or on screen, “Stereo Viewing with Anaglyphs“

red/cyan paper anaglyph glasses
• side-by-side viewing, various implementations for (small) prints or digital; some may be viewed without utilities, but most need various tools (e.g. stereoscopes…)
  • parallel-view: left image is presented left, right image is presented right
    
  • cross-view: left image is presented right, right image is presented left
• Active or passive stereo screens (need corresponding 3d-glasses)
• Dia Show projection with polarized glasses
• wiggle: a digital animation of the stereogram for viewing without stereo utilities
  

• Virtual Reality (VR) equipment
• …

last update: 18.03.2018
published: 11.08.2015

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