Graphics Reference
In-Depth Information
HMDinparticularrenderstheleftandrightviewstotheuserbasedontheirheadposition.
These are mostly used in interactive 3D video applications. Even though the viewing 3D
with eye-wears is cost effective solution, the users at home may not like to wear them due
tothegeneraldiscomfort.Moreover,theseeye-wearsintroducespecificartefactstotheste-
reoscopic image sequences. For example, with polarization glasses each eye sees a faint
versionoftheothereye'simage
[96].
Therefore,autostereoscopicdisplaysprovideconveni-
ent solution for 3D viewers and due to the wide popularity of this technique the cost for a
display unit going to be lowered in the future.
These displays can be employed to produce binocular (single user), multi-view (multiple
discretestereoscopicviews)andholoformviews.Unlikeother3Ddisplays(e.g.volumetric
display) this display supports limited number of viewers. Two design approaches for auto-
stereoscopic displays are shown in Figure5.10.Figure5.10(a)showsalenticulararrayof
cylindricallens-letsplacedinfrontofthepixelraster, directing the light from adjacent pixel
columns to different viewing slots at the ideal viewing distance. Therefore, with this
approach, each eye of the viewer sees light from only every second pixel column and thus
provides stereoscopy. Figure 5.10 (b) shows a Parallax barrier in which a mask is placed in
front of the pixel raster so that each eye sees light from only every second pixel column.
These autostereoscopic displaysdividethehorizontalresolutionoftheunderlying,typically
liquid-crystal display device into two sets. One of the two visible images (e.g. left view)
consists of every second column of pixels; the second image (e.g. right view) consists of
the other columns. The two image sequences (i.e. stereoscopic video) are captured or gen-
eratedwiththeDIBRmethodsothatoneisappropriateforeachoftheeyepair[97].Asthis
technology is still at the early age of development, there are certain issues to be addressed
such as flipping between views and vertical binding on the image
[88].
