3.1: Space perception Flashcards
depth perception
ability to see objects as 3D (specialized distance perception, which is a specialized visual perception)
2 factors involved in seeing depth
- encoding of visual scenes in up-down left-right position
2. straight lines become curves on rent (euclidean coordinates)
principle of equivalent configuration
different shapes of objects but interpreted as same because of depth cues
monocular depth cues
only one eye needed Occlusion Familiar Size Retinal Size Texture gradients angle of regard atmospheric perspective linear perspective relative distance to horizon shading motion parallax accommodation
occlusion
interposition: whatever in font is closer
Familiar size (size cues)
changes in familiar shape interpreted as reflecting changes in distance
retinal size
visual angle decreases with increasing distance
texture gradient
textured elements becomes smaller and tightly packed with distance
angle of regard
close and above/below our line of sights (angle of regard is less acute than when far away)
atmospheric perspective
farther is fuzzier because of water molecules in the air
linear perspective
illusion of depth by using parallel lines receding to a vanishing point
relative distance to horizon
things closer to horizon seem farther away
shading
shading makes 2d appear 3d
motion parallax
between us and fixation point move fast and opposite to our motion
past our fix point move slow and in same direction
accommodation
kinaesthetic information
ciliary muscles contract (Close objects)
ciliary muscles relax (far away objects)
binocular depth cues
2 eyes needed for cue
convergence
binocular disparity
convergence
angle of convergence is more acute for near than far objects
Descarte angles
not useful past 2m
binocular disparity
each is eye is separate from each other
creates a disparity
horopter
distance at which you fixate produces imaginary circle. objects that fall on the circle of the surface show no difference in disparity
veith muller circle
the circle of horopter
diplopia
double vision
happens when dont fall on horopter
greater diplopia = further away from horopter
crossed / uncrossed disparity
crossed : objects between us and horopter
uncrossed: objected beyond horopter
empiricist position of space perception
perceptual ability is learned through experience
we learn to associated cues for distance with info about distance
Berkeley 1709
Support: Visual Cliff
retinal image is inffuficient = 2D
we convert it 3d because of info learned
constructive theory of space perception
version of empiricist that is more modern
stimuli is ambiguous.
perceiver is a problem solver
distance perception = problem solving using experience
gibsonian approach
retina visual info is full of info
stimulus contains all info needed
DIRECT perception
Gibsons ground theory
Gibsons ground theory
version of sibsonian approach
distance perception solely depends on texture gradient
What do we do with the two distance perception theories?
complementary. richness of info in stimuli used to solve problem of perception
computational approach
similar to constructive direct
“we need some knowledge to perceive correctly”
but “believes in richness of visual input
final perception of distance equals
visual input, input from experiences, input from Dif modules
size perception
size constancy requires consideration of retinal image as the size can change depending on distance
size constancy theories
algorithm theory: perceptual system takes distance into account
relational theory: perceptual system uses size relation among objects to account for constancy
types of size illusions
muller-flyer (misapplied constancy) sander illusion (depth) ponzo illusion (linear perspective) horizontal-vertical illusion moon illusion (relational/mental sky dome) AMES-ROOM
Emmerts law
perceived linear size of object increases as its percieved distance increases
