Chapter 10 Flashcards
depth perception
automatic through repeated exposure of cues
identify info (cues) in a scene to perceive depth (how far or deep something is visually)
oculomotor cues
cues given based on sending the position of eyes through tension in eye muscles
depth cues created by convergence and accomodation
convergence
inward movement of eyes when focusing on nearby objects
accommodation
change in the shape of lens to focus on objects at different distances
lens flatten = far away objects; lens thicken = nearby objects
monocular cues
cues available in one eye (2D)
pictorial cues and movement based cues
pictorial cues
occlusion (object hides or partially hides from another object, making it seem farther away)
relative height (objects closer to the base of the horizon are seen as more distant than ones from the base)
relative size (when objects are of equal size, the one farther away takes up less of your field of view than the closer one)
familiar size (judging distance according to prior knowledge of sizes of objects)
perspective convergence (parallel lines appear to come together in the distance)
atmospheric perspective (occurs when distant objects appear less sharp (foggy or unclear); farther = short wavelengths)
texture gradient (elements in a scene seem more closely packed when distance increases; smaller texture appears in distance)
shadows (decrease in light intensity due to blockage of light can provide info for location; can make objects 3D)
movement based cues
sources of depth info that come from observer’s movement
motion parallax and deletion and accretion
motion parallax
close objects in direction of movement glide rapidly past but objects in the distance appear to move slowly
deletion and accretion
deletion (covering of an object)
accretion (uncovering of an object)
distance of objects perceived based on covering and uncovering of objects as an observer moves
stereoscopic depth perception
our awareness of depth through input by both eyes
2D vs 3D
2D: both eyes receive same info; images are flat; rely on monocular cues
3D: both eyes receive different info; images positioned in different viewpoints
strabismus
misalignment of eyes; one eye is suppressed, causing double vision
people w/ strabismus rely on monocular cues instead of binocular cues
binocular disparity
difference in images from left and right eyes
corresponding retinal points
points on the retina where an image overlap
objects that appear in corresponding retinal points overlap into single image
horopter
imaginary sphere that passes through the point of focus
Fall on corresponding points on the 2 retinas
noncorresponding retinal points
objects that do not fall on horopter
create different images in both eyes
absolute disparity
objects deviate from falling on corresponding retinal points
when we see double
angle of disparity
amount of absolute disparity indicates how far object is from horopter
relative disparity
difference between absolute disparity of two objects
crossed disparity
when you focus your horopter from far away, close object in front of you creates a crossed disparity
uncrossed disparity
when you focus your horopter from a close object, far object creates an uncrossed disparity
stereopsis
ability to perceive depth through binocular disparity
binocular depth cells
aka disparity selective cells
located in primary visual cortex
specialized neurons that respond to binocular disparity
specifically respond to absolute disparity
what perceptions are interrelated to perceive size?
depth and size perception
holway and boring
comparison circle (10 ft away in left hallway); test circle (10-120 ft away in right hallway) – have to adjust diameter of comparison circle to match test circle
depth cues provided: judgments of circle size based on physical size because they had cues of distance
no depth cues: judgments of circle size were similar based on size of retinal images w/o cueing of distance
size constancy
perception of an object’s size remains relatively the same even when we view the object at different distances
muller-lyer illusion
arrow + lines
misapplied size constancy scaling (view 2D as though it is 3D)
conflicting cues theory (our misperception of line length caused by conflicting info: actual length of lines and overall length of the figure)
ponzo illusion
railroad
misapplied size constancy scaling
ames room
size distance scaling (distance is same for both people but not the size)
relative size (one person taking up more space than the other in same distance)
moon illusion
apparent distance theory (horizon moon surrounded by depth cues while moon higher up has none)
angular size contrast theory (moon appears smaller when surrounded by larger objects
