Signal Processing for Stereoscopic and Multi-View 3D Displays - Signal Processing Systems - page 20

Fig. 13 Moire artifacts, caused by irregular sub-sampling: ( a )testimage,( b ) simulated effect of
the optical layers and ( c ) actual photograph of a multiview display, showing the test image in ( a ).
Fig. 14 Photographs of displays with spatial multiplexing, showing typical distortions: ( a )
multiple ghosts of an image and ( b ) imaging, or fixed-pattern noise
of different views are interspersed, and from a given angle multiple views are
simultaneously visible [ 27 , 38 , 54 ] . An example image, exhibiting multiple ghosting
artifacts is shown in Fig. 14 a . The presence of ghosting artifacts degrades the quality
of a 2D image but is especially damaging for a stereoscopic image. The presence of
repeated edges in horizontal direction introduces ambiguity in binocular disparity
and can completely destroy the binocular depth cues [ 4 , 52 , 55 ] .
In displays with a parallax barrier, the barrier creates visible gaps between the
pixels as seen in Fig. 14 b . These gaps are seen as masking artifacts, similar to the
fixed-pattern noise exhibited by some digital projectors [ 45 ] . The perceptibility of
masking is limited by physiological factors such as the optical properties of the eye,
the density of photoreceptors and the contrast sensitivity function [ 56 ] . However,
even if separate elements of the mask are visible, the brain has a limited cognitive
ability to reconstruct the underlying shape. That ability is known as the visual
Gestalt principle [ 1 ] and the interdependent visibility of patterns with different
properties is modeled as pattern masking [ 56 ] . More information about distortions,
related to spatial view multiplexing can be found in [ 40 , 47 , 49 , 50 , 53 , 54 , 57 , 58 ] .