EXAM 2 Flashcards
what is occlusion?
one object is in front of another
what is cue theory?
connection between cue and depth through previous experience with the environment
what are the different types of cues that signal depth in a scene?
1) oculomotor - position of our eyes and tension in eye muscles
2) monocular - visual info that can use only one eye
3) binocular - visual info that needs both eyes
what is convergence?
our eyes moving inward when looking at something close by
what is accommodation?
change in our lens when we focus on objects at different distances
what are the three types of monocular cues?
1) accommodation
2) pictorial cues
3) movement based cues
what are pictorial cues?
sources of info that can be depicted in a picture (ex. can be seen through images)
what are movement based cues?
sources of depth info created by movement
what is relative height?
objects near the horizon appear further away
what is familiar size?
judging distance based on our previous knowledge of an object
what is relative size?
what two objects are equal size, the one farther away will take up less of your view
what is perspective convergence?
ex. parallel railroad tracks appear to converge in the distance
what is atmospheric perspective?
distant objects appear less sharp than nearer objects
what is texture gradient?
elements being spaced more closely appear farther away
what are the two types of motion produced cues?
motion parallax and deletion/accretion
what is motion parallax?
when we move, nearby objects move very quickly and distant objects move more slowly
what is binocular depth info?
two-eyed depth perception that involves both info from the left and right eye
what is stereoscopic vision?
different viewpoints for the two eyes
what is stereoscopic depth perception?
depth perception created by input from both eyes
(ex. when looking at 3D movies, the info from our left and right eyes are slightly different)
what is strabismus?
visual system suppresses vision in one eye to avoid double vision
what is binocular disparity?
difference in the image on the left and right retinas
what is corresponding retinal points?
points on the retina that would overlap if the eyes were superimposed on each other
(ex. if something falls on the horopter, they are on corresponding retinal points)
what are non corresponding points?
images of objects that DO NOT fall on the horopter
what is absolute disparity?
how far an object is away from the corresponding point
what is the angle of disparity?
visual angle between the image of an object on the two retinas
(difference between what is on the horopter and what isn’t on the horopter)
-angle of disparity is greater for objects at a greater distance from horopter
what is crossed disparity?
image that appears BEFORE the horopter
(right image on left eye, left image on right eye)
what is uncrossed disparity?
image that appears AFTER the horopter
(left eye sees image on the left side)
how do we determine if the absolute disparity is crossed or uncrossed?
we can see if an object is in front of or behind the horopter
what is stereopsis?
relationship between disparity and what observers perceive
what is the correspondence problem
determining corresponding points based on object features can’t be the whole answer to the correspondence problem
what are binocular depth cells/disparity selective cells?
cells that respond to disparity in V1 and respond best when stimuli in the left and right eyes create a specific amount of disparity
what is the stimulus-perception relationship?
the relationship between binocular disparity and the perception of depth
what are frontal eyes?
overlapping fields of view, can use disparity to perceive depth, provides good stereoscopic depth perception
-ex. humans and cats
what are lateral eyes?
can use disparity in small overlap area to perceive depth, less bincoular disparity, wider field of vision
-ex. bunnies
what is the visual angle?
angle of an object relative to the observer’s eye
-depends on both the size of the stimulus and its distance from the observer
-when something comes closer, both the retinal image and visual angle increases
what is size constancy?
perception of an object’s size is relatively constnat even when we view the object from different distances
what is the size constancy formula?
S = K (R * D)
-S is object’s perceived size
-K is constant
-R is the size of the retinal image
-D is perceived distance
what is Emmert’s law?
relationship between the apparent distance of an afterimage and its perceived size
-the farther away an afterimage appears, the larger it will seem
what is the Muller-lyer illusion?
right vertical line appears longer than the left vertical line, even though they are both the same length
what is the misapplied size constancy scaling?
distance between the outward facing fins appears enlarged compared to the distance between inward facing fins