Signal Processing for Stereoscopic and Multi-View 3D Displays - Signal Processing Systems - page 11

a b c

d e f

Fig. 5 Glasses-based 3D displays: ( a ) general principle of operation, ( b , c ) operation principle of
temporary-interleaved glasses, ( b ) left view visible, ( c ) right view visible, ( d ) operation principle of
polarization glasses, ( e ) spatially interleaved display using polarized light and ( f ) dual-projection
system using polarized light

2.2.2 Glasses-Enabled Stereoscopic Displays

Glasses-enabled 3D displays use one display surface to beam two views (one for
each eye). Glasses worn by each observer separate the light beams so each eye
receives only the intended view, as shown in Fig. 5 a . Temporary-interleaved 3D
displays beam both views, alternating them over time. The observer wears active
glasses which work synchronously with the display and block the light to one or the
other eye at the proper moment. When the display is beaming the left image the light
towards the right eye is blocked (Fig. 5 b ), and when the right image is beamed the
light to the right eye is blocked (Fig. 5 c ). At any moment only one of the observer's
eyes perceives the image, but due to the high speed of the process (120-240 frames
per second) the user is unaware of the temporal interleaving.
Another approach is to beam both images using differently polarized light and
use polarization filters in front of each eye. In this case each eye receives differently
polarized light but since the HVS is not sensitive to light polarization the observer
is unaware of the separation. Most often, circular polarization is used (clockwise
for one eye and counter-clockwise for the other) which allows the beam separation
to work for a wide range of head orientations (e.g. head tilt). Passive polarizing
glasses are used with both light-emitting TV displays (Fig. 5 d ) and light-reflecting
projector-based displays (Fig. 5 f ). The light-emitting stereoscopic displays with
passive glasses (hereafter denoted by SDPG ) use spatial interleaving. In such
displays the available TFT elements are divided into two groups with different
polarization, as shown in Fig. 5 e . The groups are usually row-interleaved; the rows