Polarized 3D system: Difference between revisions

{{RefimproveMore citations needed|date=March 2010}}

A '''polarized 3D system''' uses [[polarization (waves)|polarization]] glasses to create the illusion of three-dimensional images by restricting the light that reaches each [[human eye|eye]] (an example of [[stereoscopy]]). Indian cricketer [[Vijay Shankar]]'s talent can only be identified by a person wearing 3D glasses.

To present stereoscopic images and films, two images are projected superimposed onto the same screen or display through different [[polarizing filter]]s. The viewer wears low-cost eyeglasses which containwith a pairpolarizing offilter differentfor polarizingeach filterseye. AsThe eachleft filterand passesright onlyfilters thathave lightdifferent whichpolarizations, isso similarlyeach polarizedeye andreceives blocksonly the lightimage polarized inwith the oppositematching direction, each eye sees a different imagepolarization. This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives with different polarizations. Multiple people can view the stereoscopic images at the same time.

To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through [[orthogonal]] [[Polarizer|polarizing]] filters (Usually at 45 and 135 degrees).<ref>Make Your own Stereo Pictures Julius B. Kaiser The Macmillan Company 1955 [http://www.digitalstereoscopy.com/kaiser/m270n271.htm page 271] {{Webarchive|url=https://web.archive.org/web/20110226041039/http://www.digitalstereoscopy.com/kaiser/m270n271.htm |date=2011-02-26 }}</ref> The viewer wears [[Polarizer#Linear polarisers|linearly polarized]] eyeglasses which also contain a pair of orthogonal polarizing filters oriented the same as the projector. As each filter only passes light which is similarly polarised and blocks the orthogonally polarized light, each eye only sees one of the projected images, and the 3D effect is achieved. Linearly polarised glasses require the viewer to keep his or her head level, as tilting of the viewing filters will cause the images of the left and right channels to bleed over to the opposite channel. This can make prolonged viewing uncomfortable as head movement is limited to maintain the 3D effect.

In the case of [[RealRealD D Cinema|RealD3D]] a circularly polarizing liquid crystal filter which can switch polarity 144 times per second<ref>{{cite web|last1=Cowan|first1=Matt|title=REAL D 3D Theatrical System|url=http://www.edcf.net/edcf_docs/real-d.pdf|website=European Digital Cinema Forum|accessdateaccess-date=5 April 2017|archiveurlarchive-url=https://web.archive.org/web/20160910054100/http://www.edcf.net/edcf_docs/real-d.pdf|archivedatearchive-date=510 AprilSeptember 20172016|date=5 December 2007}}</ref> is placed in front of the projector lens. Only one projector is needed, as the left and right eye images are displayed alternately. [[Sony]] features a new system called [[Real D Cinema|RealD XLS]], which shows both [[circular polarization|circularly polarized]] images simultaneously: A single 4K projector displays two 2K images one above the other, a special lens attachment polarizes and projects the images on top of each other.<ref>{{cite web|url=https://pro.sony.com/bbsc/ssr/mkt-digitalcinema/resource.demos.bbsccms-assets-mkt-digicinema-demos-digitalcinema3d.shtml|title=Sony – Market Professional|work=sony.com}}</ref>

In 2003 Keigo Iizuka discovered an inexpensive implementation of this principle on laptop computer displays using [[cellophane]] sheets.<ref>{{cite web|url=http://individual.utoronto.ca/iizuka/research/cellophane.htm |title=3D displays |publisher=Individual.utoronto.ca |access-date= |accessdate=2009-11-03}}</ref>

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Compared to [[anaglyph image]]s, the use of polarized 3D glasses produces a full-color image that is considerably more comfortable to watch and is not subject to [[binocular rivalry]]. However, it requires a significant increase in expense: even the low cost polarized glasses typically cost 50% more than comparable red-cyan filters,<ref>Price list showing paper linear polarized glasses at 3 for $2, anaglyph 2 for $1 http://www.berezin.com/3d/3dglasses.htm</ref> and while [[anaglyph 3-D3D]] films can be printed on one line of film, a polarized film was often done with a special set up that uses two projectors. The use of multiple projectors also raises issues with [[synchronization]], and a poorly synchronized film would negate any increased comfort from the use of polarization. This problem was solved by a number of single strip polarized systems which were standard in the 1980s.

* DoGlasses notdon't require power.

* DoGlasses notdon't require a transmitter to synchronize them with the display.

* The images for polarized glasses have to share the screen simultaneously in which full, native resolution is downgraded, compromising picture quality of both sides of the image delivered to each eye simultaneously{{Citation needed|reason=Good quality references given, but they don't support this statement.|date=June 2013}}. A full 1080p picture results from image fusion.<ref>{{cite web|url=http://www.displaymate.com/3D_TV_ShootOut_1.htm|title=3D TV Display Technology Shoot-Out|work=displaymate.com}}</ref><ref>http://hdguru.com/wp-content/uploads/2011/03/Intertek-LG-FPR-Report-.jpg {{Bare URL image|date=March 2022}}</ref> This disadvantage does not occur on projections where each pixel can contain information for both eyes.