Stereoscopic 3D: Difference between revisions

There are several techniques available used to create the illusion of a 3D image with the use of lenses. 3D displays use the same guiding principles as the visual system to exhibit depth. In each eye, slightly different perspectives are presented so that the brain uses the differences between them to give the sense of depth <ref name=”7”> Hurricane Media (2011). Stereoscopic 3D filming and graphics, how 3D works [Video]. Retrieved from https://www.youtube.com/watch?v=IYm3BmnyVrg</ref> <ref name=”8”> Techopedia. 3-D Stereo Technology (S3-D). Retrieved from https://www.techopedia.com/definition/81/3d-stereo-technology-s3d</ref> <ref name=”9”> Gouraud, G. (2011). A Developer's Guide To Stereoscopic 3D In Games. Retrieved from http://www.gamasutra.com/view/feature/134827/a_developers_guide_to_.php?print=1</ref>.

One of the techniques is polarization 3D, that can use active or passive polarized lenses (figure 1 and 2). Anaglyph 3D uses passive red cyan lenses or chromatically opposite colors. These can be considered the classic-type 3D glasses and are a type of passive lenses (figure 3). Head-mounted displays also provide S3D using a separate display optic very close to the eyes. Finally, autostereoscopic 3D is a technique that allows for 3D depth without glasses <ref name=”2”></ref> <ref name=”8”></ref>.

Active shutter has been the primary technology used in home entertainment systems. The mechanism takes advantage of the high frame rates that are available in LED and plasma TVs (120 Hz and above). The TV displays two high definition pictures at a high refreshment frequency (>60 Hz) to achieve temporal multiplexing. The shutter glasses sync with the TV to actively filter the corresponding frames so that each eye only receives the intended image <ref name=”9”></ref>.

With the autostereoscopic display technology (also referred to as parallax barrier), there is no requirement for the users to wear glasses to achieve a three-dimensional effect. The technology relies on an optical filter which divides the images and enables it to direct light to each eye. This allows the viewer to perceive a coherent left and right image. The Nintendo 3DS uses this type of display technology <ref name=”9”></ref>.

Stereoscopic vision has evolved during millions of years. It is a common feature between humans and many animals, generally predators. In these, two parallel aligned eyes deliver different perspectives of the same scene. Stereoscopic vision is an important sense that is vital for the survival of the animals who possess it <ref name=”10”> Stereo3d. Basics/Quick-Info. Retrieved from http://www.stereo3d.com/3dhome.htm</ref>.

Charles Wheatstone first developed the stereoscope in 1938. His research demonstrated that the brain processes the images from each eye into a single three-dimensional object. When two stereoscopic images were viewed side by side through a stereoscope, a sense of depth and immersion was created. The design principles of the stereoscope are still applied today in things like the Google Cardboard and low budget VR HMDs for mobile phones <ref name=”11”> Virtual Reality Society. History Of Virtual Reality. Retrieved from https://www.vrs.org.uk/virtual-reality/history.html</ref>.

The popular View-Master stereoscope was patented in 1939, and was used for “virtual tourism”. In 1949 David Brewster suggested the use of lenses, giving rise to the lenticular stereoscope. The cinematographer Morton Heilig developed the Sensorama in the mid-1950s. It was an arcade-style theatre cabinet that stimulated all the senses. It had stereoscopic 3D display, stereo speakers, fans, smell generators, and a vibrating chair with the objective of immersing the viewer in the film. Heilig created six short films for the Sensorama. He was also responsible for the Telesphere Mask, that was patented in 1960. It was the first example of a HMD - although without motion tracking and for use with non-interactive film medium. This headset provided S3D and wide vision with stereo sound <ref name=”11”></ref>.