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Depth perception
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Images removed due to copyright restrictions.
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Please refer to lecture video�
Cues used for coding depth in the brain
Oculomotor cues Visual cues
accommodation vergence
Binocular stereopsis
Monocular motion parallax shading interposition size perspective
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Stereopsis, basic facts and demos
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Two simple methods for creating stereo images
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stereo camera swiveled regular camera
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Demos, page 1 6
Image is in public domain.
Images removed due to copyright restrictions.
Demos, page 1 & 2 7
Please see lecture video or Figure 1 of Schiller, Peter H., Geoffrey L. Kendall, et al. "Depth
Perception, Binocular Integration and Hand-Eye Coordination in Intact and Stereo Impaired
Human Subjects." Journal of Clinical & Experimental Ophthalmology 3, (210).
Autostereogram from Magic Eye
Images removed due to copyright restrictions.
Autostereograms: see Howard and Rogers, Depth Perception, Vol 2, pp. 549-556.
Demos, page 3 8
Please see lecture video or the autostereogram from The Magic Eye, Volume I:A New Way of Looking at the World. Andrews McMeel Publishing, 1993.
Retinal disparity utilized for stereopsis
Target hits corresponding retinal points Target hits non-corresponding retinal points
Vieth-Muller circle
target
fix fixtarget
y x x y
x = yx = y
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Stereopsis, neuronal responses
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-10O
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0 1 2sec
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ispa
rity
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ree)
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th (c
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Image by MIT OpenCourseWare.11
V1 cell response to drifting bars at varied stereo depths
0 1 2 3
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0
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Dis
parit
y (d
egre
e)
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m)
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sec
Key down
Image by MIT OpenCourseWare.12
V1 cell response to drifting bars at varied stereo depths
.10 .05 00 05 10 .10 .05 00 05 10 .10 .05 00 05 10
.10 .05 00 05 .05 00 0510
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Tuned excitatory near
LR
Tuned excitatory farTuned excitatory zero
Far
Horizontal display (deg)
Tuned inhibitoryNearN
eura
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pons
es (i
mpu
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per
sec)
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.10 .05 00 05 10
Image by MIT OpenCourseWare.
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Basic cell types for stereo
Near Fixation point FarDepth
Tuned inhibitory
Neu
ral a
ctiv
ityNear
Tuned excitatory
Far
]]
Image by MIT OpenCourseWare.
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Basic cell types for stereo
The effects of V4 and MT lesions on stereoscopic depth perception
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Images removed due to copyright restrictions.
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Please see lecture video or Figure 1 of Schiller, Peter H., Geoffrey L. Kendall, et al. "Depth
Perception, Binocular Integration and Hand-Eye Coordination in Intact and Stereo Impaired
Human Subjects. "Journal of Clinical & Experimental Ophthalmology 3, (210).
Graphs removed due to copyright restrictions.
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Please see lecture video or Schiller, Peter H. "The Effects of V4 and Middle
Temporal (MT) Area Lesions on Visual Performance in the Rhesus Monkey."
Visual Neuroscience 10, no. 4 (1993): 717-46.
Stereopsis
Motion parallax
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MOTION PARALLAX, the eye is stationary
A B C
Velocity of motion: A fastest, C slowest, creating velocity gradient With rigidity constraint highest relative velocity is judged to be closest
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MOTION PARALLAX, the eye tracks
object motion
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a
b
1
2
a
b eye movement
The eye tracks the circle, which therefore remains stationary on the fovea
Objects nearer than the one tracked move at greater velocities on the retinal surface than objects further; the further objects actually move in the opposite direction on the retina.
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Motion parallax
To derive depth information from motion parallax neurons are needed that provide information about velocity and direction of motion and perhaps also about differential motion.
The majority of cells in V1 are direction and velocity selective. Some appear also to be selective for differential motion.
Cells that process motion parallax have also been found in MT.
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Brain activation by stereopsis and motion parallax in normal and stereoblind subjects with fMRI
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Images are projected here
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A: Stereo
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B: Parallax
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C: Stereo + Parallax
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Shading
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The power of shading for depth perceptionThe power of shading for depth perception
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Examples of the 12 different shadings used
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The next five displays have identical, repeating elements which are shaded differently in each set yielding a variety of stable and conflicting percepts
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Stereo and shading in harmony and in conflict
Demos, page 4-7
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f f f
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Putting stereo, parallax and shading together
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3HUFHSWLRQ35, no. 11 (2006): 1521.
about the visual system."
about the
Image removed due to copyright restrictions.
Please see lecture video or see Display 24 of Schiller, Peter H., and Christina E.
Carvey. "Demonstrations of Spatiotemporal Integration and What they Tell us
About the Visual System." Perception 35, no. 11 (2006): 1521.
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Separate and combined disparity, parallax and shading depth cues
Graphs removed due to copyright restrictions.
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Please see lecture video or Figure 3a,b of Schiller, Peter H., Warren M. Slocum,
et al. "The Integration of Disparity, Shading and Motion Parallax Cues for Depth
Perception in Humans and Monkeys." Brain Research 1377 (2011): 67-77.
Perspective
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Image removed due to copyright restrictions.
Please see lecture video or see William O'Brian, "Because it's
here, that's why," New Yorker, September 21, 1963, 42.
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Perspective illusion
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The Savage family
Painting is in public domain. Edward Savage 56
The Savage family
Hand-eye coordination and Binocular integration tests
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Needle test
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Movie of needle test needle_binoc needle_monoc
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Touch-panel test
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Examples of test of binocular integration
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Binocular integration test, figures
A
B
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Binocular integration test, words
A
B
SS UU DD TT RR YY
SS TT UU RR DD YY SS TT UU RR DD YY
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Summary, depth:
1. Numerous mechanisms for analyzing depth have been identified that include vergence and accommodation, stereopsis, parallax, shading, and perspective.
2. Several cortical structures process stereopsis utilizing disparity information; the number of disparities represented is limited as in the case of color coding.
3. Utilizing motion parallax for depth processing necessitates neurons specific for direction, velocity and differential velocity; several areas, including V1 and MT process motion parallax.
4. Area MT contributes to the analysis of motion, motion parallax, depth, and flicker; however, these analyses are also carried out by several other structures.
5. Litte is known at present about the manner in which information about shading and perspective is analyzed by the brain.
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9.04 Sensory SystemsFall 2013
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