Download Stereopsis Convergence Focus

STEREOSCOPY
The illusion of Depth
What is Stereoscopy?
Derived from Greek
word “stereo” meaning
“solid” and “scopy”
meaning “viewed”
Early form of 3D image
using lenses:
Anaglyph Stereo Image
History
 280
BC – Postulated by
Euclid
 1833 – first stereoscopy
using mirrors.
Modern Stereoscopic methods: Passive
Passive
Viewers:
Color Filtering
Standard is
Red for right
eye and Cyan
for left eye
Modern Stereoscopic methods: Active
Active
Viewers:
Switching
Glasses switch
eyes
coordinated
with screen
Stereoscopy: How it works
The eye and the brain conspire to fool you !!!
Stereopsis: The Brain…under 50 ft.
Brain uses
feedback from the
eye muscles to
determine parallax:
Convergence.
Stereopsis: The Brain…beyond 50 ft.
Brain uses
feedback from the
eye muscles to
determine parallax
Convergence.
But, Also….
Stereopsis: The Brain…beyond 50 ft
Brain senses differences
between images on the
retina.
Factors influencing Focus
and Tracking.
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




Angular size of objects
Classical perspective
Desaturation of colors
Atmospheric Distortion
Shadows
Motion Parallax
Stereopsis: Problems
Stereopsis
 Convergence
 Focus

Orthogonal distortion



Stereopsis – processes of
convergence and focus
Convergence – brain solves
for parallax
Focus – eye and brain
solve for sharpness
Stereoscopic illusions
require Convergence and
focus to work separately.
Stereopsis: Problems
Stereopsis
 Convergence
 Focus


Orthogonal distortion
The smaller something is,
the more distorted the
angles and shapes they
form.
Your brain resists
interpreting large angles
on a small display.
Modern Applications: Video
3D movies have been available
since “The Power of Love” -1922
 The increased cost of creation
must be offset (costs more to see)
 Few people have 3D display
tech for aftermarket viewing
 Digital videography is dropping
the cost of 3D filming.

Applications: Virtual Reality
 As
a sub-function of
smartphones making them
much more prevalent.
 Headsets
 “Window on Reality” using
camera with overlay
images. (Pokémon game)
Credits
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1- “The Illusion of Reality in Stereoscopy”, CC0, Donald E Seminek
3- Image: Women using Stereoscope, CC0, Hyperlink
4- Image: Stereoscopy by Osiponkive, CC0, Hyperlink
5- image via Creative Commons, CC0, – Author Locafox.de
7- Astronomygcxe.co.uk with author’s permission
12- Pixabay, CC0, no credits
13- Pixabay, CC0, Stefan Schweihofer, Germany
Widescreen Test Pattern (16:9)
Aspect Ratio Test
(Should appear
circular)
4x3
16x9
Perspective
One-point Perspective
Two-point Perspective
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Angular Size and Motion
The Moon’s motion across
the sky is about 15 degrees
per hour.
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