3D display
Encyclopedia
A 3D display is any display device
capable of conveying a stereoscopic
perception of 3-D depth to the viewer. The basic requirement is to present offset images that are displayed separately to the left and right eye. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth. Although the term "3D" is ubiquitously used, it is important to note that the presentation of dual 2-D images is distinctly different from displaying an image in three full dimensions
. The most notable difference is that the observer is lacking any freedom of head movement and freedom to increase information about the 3-dimensional objects being displayed. Holographic displays
do not have this limitation, so the term "3D display" fits accurately for such technology.
Similar to how in sound reproduction it is not possible to recreate a full 3-dimensional sound field merely with two stereophonic speakers, it is likewise an overstatement of capability to refer to dual 2-D images as being "3D". The accurate term "stereoscopic" is more cumbersome than the common misnomer "3D", which has been entrenched after many decades of unquestioned misuse.
The optical principles of multiview auto-stereoscopy have been known for over 60 years. Practical displays with a high resolution have recently become available commercially.
, described by Sir Charles Wheatstone in the 1830s
, stereoscopic technology provides a different image to the viewer's left and right eyes. Examples of this technology include anaglyph image
s and polarized glasses. Stereoscopic technologies generally involve special spectacles.
and specular holography
.
identical to that which would emanate from the original scene, with both horizontal and vertical parallax across a large range of viewing angles. The effect is similar to looking through a window at the scene being reproduced; this may make CGH the most convincing of the 3D display technologies, but as yet the large amounts of calculation required to generate a detailed hologram largely prevent its application outside of the laboratory.
s instead of pixel
s. Volumetric displays include multiplanar displays, which have multiple display planes stacked up, and rotating panel displays, where a rotating panel sweeps out a volume.
Other technologies have been developed to project light dots in the air above a device. An infrared laser is focused on the destination in space, generating a small bubble of plasma which emits visible light.
Display device
A display device is an output device for presentation of information in visual or tactile form...
capable of conveying a stereoscopic
Stereoscopy
Stereoscopy refers to a technique for creating or enhancing the illusion of depth in an image by presenting two offset images separately to the left and right eye of the viewer. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth...
perception of 3-D depth to the viewer. The basic requirement is to present offset images that are displayed separately to the left and right eye. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth. Although the term "3D" is ubiquitously used, it is important to note that the presentation of dual 2-D images is distinctly different from displaying an image in three full dimensions
Three-dimensional space
Three-dimensional space is a geometric 3-parameters model of the physical universe in which we live. These three dimensions are commonly called length, width, and depth , although any three directions can be chosen, provided that they do not lie in the same plane.In physics and mathematics, a...
. The most notable difference is that the observer is lacking any freedom of head movement and freedom to increase information about the 3-dimensional objects being displayed. Holographic displays
Holographic display
Holographic display is a display technology that has the ability to provide all four eye mechanism: binocular disparity, motion parallax, accommodation and convergence...
do not have this limitation, so the term "3D display" fits accurately for such technology.
Similar to how in sound reproduction it is not possible to recreate a full 3-dimensional sound field merely with two stereophonic speakers, it is likewise an overstatement of capability to refer to dual 2-D images as being "3D". The accurate term "stereoscopic" is more cumbersome than the common misnomer "3D", which has been entrenched after many decades of unquestioned misuse.
The optical principles of multiview auto-stereoscopy have been known for over 60 years. Practical displays with a high resolution have recently become available commercially.
Stereoscopic
Based on the principles of stereopsisStereopsis
Stereopsis refers to impression of depth that is perceived when a scene is viewed with both eyes by someone with normal binocular vision. Binocular viewing of a scene creates two slightly different images of the scene in the two eyes due the the eyes' different positions on the head...
, described by Sir Charles Wheatstone in the 1830s
1830s
- Wars :* The First Opium War between the United Kingdom and the Qing Empire of China started in 1839. It would end three years later with the signing of the Treaty of Nanking on 29 August 1842.- Internal conflicts :* French Revolution of 1830...
, stereoscopic technology provides a different image to the viewer's left and right eyes. Examples of this technology include anaglyph image
Anaglyph image
Anaglyph images are used to provide a stereoscopic 3D effect, when viewed with glasses where the two lenses are different colors, such as red and cyan. Images are made up of two color layers, superimposed, but offset with respect to each other to produce a depth effect...
s and polarized glasses. Stereoscopic technologies generally involve special spectacles.
Autostereoscopic
Autostereoscopic display technologies use optical components in the display, rather than worn by the user, to enable each eye to see a different image. The optics split the images directionally into the viewer's eyes, so the display viewing geometry requires limited head positions that will achieve the stereoscopic effect. Automultiscopic displays provide multiple views of the same scene, rather than just two. Each view is visible from a different range of positions in front of the display. This allows the viewer to move left-right in front of the display and see the correct view from any position. Example technologies include parallax barriersParallax barriers
A parallax barrier is a device placed in front of an image source, such as a liquid crystal display, to allow it to show a stereoscopic image or multiscopic image without the need for the viewer to wear 3D glasses...
and specular holography
Specular holography
Specular holography is a technique for making three dimensional imagery by controlling the motion of specularities on a two-dimensional surface. The image is made of many specularities and has the appearance of a 3D surface-stippling made of dots of light...
.
Computer-generated holography
Research into holographic displays has produced devices which are able to create a light fieldLight field
The light field is a function that describes the amount of light faring in every direction through every point in space. Michael Faraday was the first to propose that light should be interpreted as a field, much like the magnetic fields on which he had been working for several years...
identical to that which would emanate from the original scene, with both horizontal and vertical parallax across a large range of viewing angles. The effect is similar to looking through a window at the scene being reproduced; this may make CGH the most convincing of the 3D display technologies, but as yet the large amounts of calculation required to generate a detailed hologram largely prevent its application outside of the laboratory.
Volumetric displays
Volumetric displays use some physical mechanism to display points of light within a volume. Such displays use voxelVoxel
A voxel is a volume element, representing a value on a regular grid in three dimensional space. This is analogous to a pixel, which represents 2D image data in a bitmap...
s instead of pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
s. Volumetric displays include multiplanar displays, which have multiple display planes stacked up, and rotating panel displays, where a rotating panel sweeps out a volume.
Other technologies have been developed to project light dots in the air above a device. An infrared laser is focused on the destination in space, generating a small bubble of plasma which emits visible light.