Three-dimensionality is a sensation produced by our brain, based on different information feeds:
- Disparity between the two slightly offset images seen by our eyes,
- Eye vergence muscular effort,
- Perspective and relative size of objects,
- Shadows and reflections,
- Occlusion effects and relative displacement of objects.
Binocular vision is of course predominant to perceive three-dimensionality. Therefore, classical 3D display processes use two offset views of a scene, called stereo pair. 19th century stereoscopes combined two images of a stereo pair laid side by side, whereas present 3D movies alternately project left and right images, while special glasses discriminate which image will be seen by each eye.
Technology
Alioscopy 3D displays are auto-stereoscopic because the three-dimensional effect is immediate and doesn't rely on special eyewear. Content however is special. Instead of assembling one left and one right image, it actually includes n images forming n-1 successive stereo pairs. These n views are multiplexed into one single Alioscopy image, using a proprietary algorithm.
Parts of the following image appear to be blurred on your computer screen. If you were watching the original HD image full screen on an Alioscopy 3D displays, this blur would convert into a staggering 3D effect, and the image would be crisp everywhere. The right wheel of the front airplane would show on the display plane itself, but the tip of its wing would pop-out 40 cm outside of a 42" display, whereas the plane flying in the back would appear to be flying 60 cm behind the screen.
Sample of Alioscopy 8 view image
In order to convert this blur into a three-dimensional feeling and to allow each eye to see a different image, an optical component combining 720 cylindrical micro lenses, called lenticular array, is positioned in a slant on the screen with great accuracy.
Lenticular array covering the LCD panel in a slant
These micro lenses act as tiny magnifying glasses, blowing up a different point of view according to the angle from which they are being looked at. They prevent each eye from seeing more than one point of view at a time among the multiple views mixed in each image. Since both eyes watch the display from slightly different angles, they both see a different image on-screen, therefore creating a three-dimensional sensation in the brain.
