3D display
The accurate term "stereoscopic" is more cumbersome than the common misnomer "3D", which has been entrenched after many decades of unquestioned misuse.
Based on the principles of stereopsis, described by Sir Charles Wheatstone in the 1830s, stereoscopic technology provides a different image to the viewer's left and right eyes.
Traditional stereoscopic photography consists of creating a 3D illusion starting from a pair of 2D images, a stereogram.
The easiest way to enhance depth perception in the brain is to provide the eyes of the viewer with two different images, representing two perspectives of the same object, with a minor deviation exactly equal to the perspectives that both eyes naturally receive in binocular vision.
The side-by-side method is extremely simple to create, but it can be difficult or uncomfortable to view without optical aids.
In 1939, a modified and miniaturized variation of this technology, employing cardboard disks containing seven pairs of small Kodachrome color film transparencies, was introduced as the View-Master.
The user typically wears a helmet or glasses with two small LCD or OLED displays with magnifying lenses, one for each eye.
Head-mounted displays may also be coupled with head-tracking devices, allowing the user to "look around" the virtual world by moving their head, eliminating the need for a separate controller.
Owing to rapid advancements in computer graphics and the continuing miniaturization of video and other equipment these devices are beginning to become available at more reasonable cost.
A recent development in holographic-waveguide or "waveguide-based optics" allows a stereoscopic images to be superimposed on real world without the uses of bulky reflective mirror.
Glasses containing liquid crystal that will let light through in synchronization with the images on the cinema, television or computer screen, using the concept of alternate-frame sequencing.
A drawback of this method is the need for each person viewing to wear expensive, electronic glasses that must be synchronized with the display system using a wireless signal or attached wire.
This is not necessarily a usage problem; for some types of displays which are already very bright with poor grayish black levels, LCD shutter glasses may actually improve the image quality.
To present a stereoscopic picture, two images are projected superimposed onto the same screen through different polarizing filters.
This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives.
The use of more spectral bands per eye eliminates the need to color process the image, required by the Dolby system.
Evenly dividing the visible spectrum between the eyes gives the viewer a more relaxed "feel" as the light energy and color balance is nearly 50–50.
[citation needed] Although DPVO dissolved its business operations, Omega Optical continues promoting and selling 3D systems to non-theatrical markets.
In addition to the passive stereoscopic 3D system, Omega Optical has produced enhanced anaglyph 3D glasses.
The Pulfrich effect is a psychophysical percept wherein lateral motion of an object in the field of view is interpreted by the visual cortex as having a depth component, due to a relative difference in signal timings between the two eyes.
In order to see the stereoscopic image, the viewer must sit within a very narrow angle that is nearly perpendicular to the screen, limiting the size of the audience.
Other examples for this technology include autostereoscopic LCD displays on monitors, notebooks, TVs, mobile phones and gaming devices, such as the Nintendo 3DS.
An infrared laser is focused on the destination in space, generating a small bubble of plasma which emits visible light.
The 3D objects can be viewed without wearing any special glasses and no visual fatigue will be caused to human eyes.
In 2013, a Silicon valley Company LEIA Inc started manufacturing holographic displays well suited for mobile devices (watches, smartphones or tablets) using a multi-directional backlight and allowing a wide full-parallax angle view to see 3D content without the need of glasses.
Each of these display technologies can be seen to have limitations, whether the location of the viewer, cumbersome or unsightly equipment or great cost.
