Signal Processing for Stereoscopic and Multi-View 3D Displays - Signal Processing Systems - page 13

a b c

Fig. 7 Optical filters for autostereoscopic displays: ( a ) lenticular sheet, ( b ) parallax barrier and
( c ) temporally-interleaved patterned retarder

One way to have each view with the full resolution of the display is to use
temporal interleaving. One example is the 3D display with the patterned retardation
film produced by 3M [ 37 ] . It distributes the light into two perspective views in a
sequential manner, as shown in Fig. 7 c . The display uses a standard TFT panel
and two separate backlighting sources. The two backlights are turned on and off
in counter phase so that each backlight illuminates one view. The switching is
synchronized with the LCD which displays different-perspective images at each
backlit switch-on time. The role of the 3-D film is to direct the light coming from the
activated backlight to the corresponding eye. More information on autostereoscopic
displays can be found in [ 30 , 38 , 39 ] .

2.2.4 Multiview Displays

Most multiview 3D displays work in a similar fashion to the spatially-multiplexed
dual-view ones. However, instead of having their sub-pixels separated into two
views, multiview displays have more views, typically 8 to 24. The current generation
of multiview displays uses the same basic principles for light distribution; lenticular
sheets [ 35 ] or slanted parallax barriers [ 36 ] . The lenticular sheet works by refracting
the light as shown in Fig. 8 a , and the parallax barrier works by blocking the
light in certain directions as shown in Fig. 8 b . In both cases the intensity of the
light rays passing through the filter changes as a function of the angle [ 35 ] . Since
sub-pixels appear displaced in respect to the optical filter, their light is redirected
towards different positions. As a result, differently colored components of one pixel
belong to different views. Respectively, the image formed by one view will be a
combination of color components (sub-pixels) of various pixels across the TFT
screen. When red, green and blue sub-pixels are visible from the same direction