Scarica (PDF – 6.19 MB)

Stereopsis works together with monocular depth cues to produce
depth perception. Monocular cues are elements of a 2D image which can
provide depth information. Some monocular cues are motion parallax,
perspective, occlusion, relative size of objects [47].
Stereoscopic displays obtain a depth effect by displaying a parallax
value for each image pixel. Given two views of the same scene from
slightly different side-by-side viewpoints, parallax is the horizontal off-
set, measured on the display, between pixels corresponding in the left
and in the right. It produces a directly proportional disparity on the
retinae. Pixels having zero parallax (figure 8a) will produce zero dis-
Figure 8: (a) Zero parallax. (b) Positive parallax. (c) Negative parallax. (d)
Divergent parallax. [46]
parity on the retinae, and will be seen as lying on the plane of the
display. Pixels having positive parallax (figure 8b) will produce posi-
tive disparity, and will be seen as if they were behind the display. Vice
versa, pixels having negative parallax (figure 8b) will produce negative
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