Perspective!!! Igor Juricevic & John M. Kennedy. Outline Basics of perspective –What is...
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Transcript of Perspective!!! Igor Juricevic & John M. Kennedy. Outline Basics of perspective –What is...
Perspective!!!Perspective!!!Igor Juricevic & John M. Kennedy
Outline
• Basics of perspective– What is perspective?– Why study perspective?– Why study perspective pictures?
• Experiments 1-4– The ART theory– Is the ART theory general across observer position?– Is the ART theory general across eye-height?– Is the ART theory general across object orientation?
What is perspective?
• Leonardo– Perspective is nothing else than seeing a
place or objects behind a plane of glass, quite transparent, on the surface of which the objects behind the glass are to be drawn.
What is perspective?
from Taylor (1719)
What is perspective?What is perspective?
Why study perspective?
• Perspective is the basic geometry of the visual system– Determines the information available to the
visual system
Why study perspective pictures?
• Reason 1: explain picture perception• Since the Renaissance… paradoxes
concerning picture perception have plagued the consciousness of mankind
• Explanations by:– Leonardo da Vinci– Albert Einstein– other guys…– have all FAILED!!!
Reason 1: explain picture perception
Reason 1: explain picture perception
Reason 1: explain picture perception
Reason 1: explain picture perception
Why study perspective pictures?
• Reason 1: explain picture perception
• Reason 2: explain spatial perception
Reason 2: explain spatial perception
• The assumption– There is nothing special about picture
perception– Picture Perception = Everyday Perception
• So, a theory that can account for picture perception will account for everyday perception as well
• But…– Why not just study Everyday Perception?
Reason 2: explain spatial perception
• Why not just study everyday perception?
• Newtonian Physics vs. Einstein’s Physics
Reason 2: explain spatial perception
• Why not just study everyday perception?• Everyday perception will give you a
“Newtonian Physics” theory of vision• Picture perception may give you an
“Einstein’s Physics” theory of vision– Why? Because you can put people in novel
situations– i.e., you can have the observer at the wrong
vantage point
The ART theory
Experiment 1
Experiment 1
Experiment 1
Experiment 1
Experiment 1
Experiment 1
Experiment 1
Experiment 1
Observer is:TOO FAR
Observer is:TOO CLOSE
Observer is:JUST RIGHT
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:TOO FAR
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:TOO FAR
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:TOO FAR
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:JUST RIGHT
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:TOO CLOSE
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:TOO CLOSE
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Observer is:TOO CLOSE
The ART theory
• The “Angles and Ratios Together” theory
• Angles– “Angle from the Normal”
• Ratios– Visual Angle ratios
• Together– Together
The ART theoryDD
OO
CC
BBAA
The ART theory: Angle from the Normal
DD
OO
CC
BBAA
The ART theory: Visual Angle Ratio (Side/Bottom)
DD
OO
CC
BBAA
The ART theory
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ual
An
gle
Rat
io
ElongatedCompressedSquare
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ual
An
gle
Rat
io
ElongatedCompressedSquare
The “ART Theory Ranges”
The ART theory
• Able to account for Experiment 1…
• Can it generalize to other situations?
• Like…
The ART theory
• Changes in observer position?
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Compressed (Average Response <90)
Perspective Constancy (Average Response 90-110)
Elongated (Average Response >110)
Experiment 1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ual
An
gle
Rat
io (
Sid
e/B
ott
om
)
ElongatedSquareCompressed
Experiment 2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ual
An
gle
Rat
io (
Sid
e/B
ott
om
)
ElongatedSquareCompressed
Experiments 1 & 2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ua
l A
ng
le R
ati
o (
Sid
e/B
ott
om
)
Elongated 1
Square 1
Compressed 1
Elongated 2
Square 2
Compressed 2
The ART theory
• Changes in observer position?
YES
The ART theory
• Changes in eye-height?
High
Mid
Low
Experiment 3
0
0.5
1
1.5
2
2.5
3
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ua
l An
gle
Ra
tio
(S
ide
/Bo
tto
m)
ElongatedSquareCompressed
Experiments 1 & 2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ua
l A
ng
le R
ati
o (
Sid
e/B
ott
om
)
Elongated 1
Square 1
Compressed 1
Elongated 2
Square 2
Compressed 2
Experiments 1, 2, & 3
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ua
l A
ng
le R
ati
o (
Sid
e/B
ott
om
)
ElongatedSquareCompressed
The ART theory
• Changes in eye-height?
YES
The ART theory
• Changes in orientation?
Experiments 1, 2, and 3 Experiment 4
Observer is:TOO FAR
Observer is:TOO FAR
Observer is:TOO FAR
Observer is:JUST RIGHT
Observer is:TOO CLOSE
Observer is:TOO CLOSE
Observer is:TOO CLOSE
Experiment 4
0
0.5
1
1.5
2
2.5
3
3.5
4
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ual
An
gle
Rat
io (
Sid
e/B
ott
om
)
Elongated
Square
Compressed
Experiments 1, 2, & 3
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ua
l A
ng
le R
ati
o (
Sid
e/B
ott
om
)
ElongatedSquareCompressed
Experiments 1, 2, 3, & 4
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
Angle from Normal (radians)
Vis
ual
An
gle
Rat
io (
Sid
e/B
ott
om
)
Elongated 1 Square 1 Compressed 1
Elongated 2 Square 2 Compressed 2
Elongated 4d Square 4d Compressed 4d
Elongated 3 Square 3 Compressed 3
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 0.2 0.4 0.6 0.8 1 1.2
ElongatedSquareCompressed
The ART theory
• Changes in orientation?
Experiments 1, 2, and 3 Experiment 4
MAYBE
Conclusions
• The ART theory begins to explain some of the paradoxes of picture perception
• The ART theory can be applied to perception of the real world (i.e., “Everyday Perception”)
• May need to add factors to ART theory to deal with orientation
Thank you.