Active shutter 3D system: Difference between revisions

[[Image: CrystalEyes shutter glasses.jpg|thumb|A pair of CrystalEyes shutter glasses]]

[[File:Active-3d-shutter-technology.gif|thumb|Functional principle of active shutter 3D

systems]]

 

Modern active shutter 3D systems generally use liquid crystal shutter glasses (also called "LC shutter glasses"<ref>[http://portal.acm.org/citation.cfm?id=11215 "LC shutter glasses provide 3-D display for simulated flight"], [[Society for Information Display|Information Display Magazine]], Vol. 2, Issue 9, September 1986</ref> or "active shutter glasses"<ref>[http://www.physorg.com/news173082582.html "Active Shutter 3D Technology for HDTV"], [[PhysOrg]], September 25, 2009</ref>). Each eye's glass contains a [[liquid crystal]] layer which has the property of becoming opaque when [[voltage]] is applied, being otherwise [[Transparency (optics)|transparent]]. The glasses are controlled by a timing signal that allows the glasses to alternately block one eye, and then the other, in synchronization with the [[refresh rate]] of the screen. The timing synchronization to the video equipment may be achieved via a wired signal, or wirelessly by either an [[infrared]] or [[radio frequency]] (e.g. [[Bluetooth]], DLP link) transmitter. Historic systems also used spinning discs, for example the [[Teleview]] system.

 

 

== Advantages and disadvantages ==

 

 

===Advantages===

* Unlike in a [[Polarized 3D system]], where the (usually) horizontal spatial resolution is halved, the active shutter system can retain full resolution ([[1080p]]) for both the left and right images. Like any system, manufacturers of televisions may choose not to implement the full resolution for 3D playback but use halved vertical resolution (540p) instead.<ref>[https://web.archive.org/web/20160313043030/http://www.digitalversus.com/tv-television/investigation-active-3d-tvs-full-hd-3d-guaranteed-a1467.html Investigation: Active 3D TVs, Full HD 3D Guaranteed?] Digitalversus.com. 5 December 2011. (Archived.)</ref>

 

===Disadvantages===

* Flicker can be noticed except at very high refresh rates, as each eye is effectively receiving only half of the monitor's actual refresh rate. However, modern LC glasses generally work in higher refresh rates and eliminate this problem for most people.

* When used with LCDs, esp. early ones, extreme localized differences between the image to be displayed in one eye and the other may lead to [[crosstalk]], due to LCD panels' pixels sometimes being unable to fully switch, for example from black to white, in the time that separates the left eye's image from the right one. With techniques like [[Response time compensation|overdrive]], which addressed the needs of fast video games, advancements in the panel's response time has led to displays that rival or even surpass passive 3D systems.

* Frame rate has to be double that of a non-3D, anaglyph, or [[polarized 3D system]]s to get an equivalent result. All equipment in the chain has to be able to process frames at double rate; in essence this doubles the hardware requirements.

 

==Standards==

 

Field Sequential has been used in video games, VHS and VHD movies and is often referred to as HQFS for DVDs, these systems use wired or wireless LCS glasses.

In 1984, [[Milton Bradley Company|Milton Bradley]] released the 3D Imager, a primitive form of active shutter glasses that used a motorized rotating disc with transparencies as physical shutters, for the [[Vectrex]]. Although bulky and crude, they used the same basic principle of rapidly alternating imagery that modern active shutter glasses still use.

 

 

In 1993 [[Pioneer Corporation|Pioneer]] released the [[LaserActive]] system which had a bay for various "PAC's" such as the Mega LD PAC and LD-ROM² PAC. The unit was 3D capable with the addition of the LaserActive 3D goggles (GOL-1) and the adapter (ADP-1).

The glasses kits came with driver software which intercepted API calls and effectively rendering the two views in sequence; this technique required twice the performance from the [[graphics processing unit|graphic card]], so a high-end device was needed. Visual glitches were common, as many 3D [[game engine]]s relied on 2D effects which were rendered at the incorrect depth, causing disorientation for the viewer. Very few CRT displays were able to support a 120&nbsp;Hz [[refresh rate]] at common gaming resolutions of the time, so high-end CRT display was required for a flicker-free image; and even with a capable CRT monitor, many users reported flickering and headaches.

 

 

SplitFish EyeFX 3D was a stereo 3D shutter glasses kit for the Sony [[PlayStation 2]] released in 2005; it only supported standard-definition CRT TVs. The accessory included a pass-through cable for the PS2 gamepad; when activated, the attached accessory would issue a sequence of rapidly alternating left–right movement commands to the console, producing a kind of "[[wiggle stereoscopy]]" effect additionally aided by the wired LC shutter glasses which worked in sync with these movements.<ref>{{cite web |url=http://www.psillustrated.com/psillustrated/hard_rev.php/351/eyefx-3d-version-230-ps2.html |title=EyeFX 3D (Version 2.30) |publisher=Psillustrated.com |access-date=2011-03-30}}</ref> The kit arrived too late in the product cycle of the console when it was effectively replaced by the [[PlayStation 3]], and only a few games were supported, so it was largely ignored by gamers.<ref>{{cite web |url=http://www.cheatcc.com/psx2/rev/eye_fx_3d_ps2_adapter.html |title=3D Eye FX Adapter by SplitFish Review / Preview for PlayStation 2 (PS2) |publisher=Cheatcc.com |access-date=2011-03-30}}</ref>

==Therapeutic alternating occlusion==

{{Main|Alternating occlusion training}}

 

==See also==

*[[Digital 3D]]

*[[Teleview]]