depth, size and auditory perception

perceiving depth

oculomotor cues, monocular cues, biocular cues

oculomotor cues

cues based on our ability to sense the position and state of our eyes

monocular cues

cues based on the visual information avaliable within one eye

binocular cues

cues based on the visual information within both eyes

two main types of oculomotor cues

binocular convergence, accomodation

binocular convergence

the simultaneous, inward rotation of both eyes towards each other to focus on a single close object .eyes converging, used to sense how far something is.

accomodation

the act of the lens of our eye fattens or thins based off how far the thing we are looking for is at. far point = thin, near point = fat

three types of monocular cues

accommodation, pictorial cues, movement-based cues

pictorial cues

occlusion, relative height, familiarity and relative size, perspective convergence, atmospheric perspective, texture gradient, shadows

shadows

cue for depth perceptin (humans assume light is coming from above)

movement based cues

motion parallax, delection and accretion

motion parallax

estimating how far an object is based on how fast it moves. objects far away seem slower; objects closer seem faster

deletion

objects occulde others

accretion

objects present again.

why? objects far away seem slower; objects closer seem faster

far - less movement needs to be done across retina = moves slowly

close - more movement needs to be done across the retina. moves faster

binocular cues - binocular disparity

our left and right eyes are offset relative to eachother, see world from slightly different viewpoitns

horopter

the specific, imaginary curve or surface in 3D space where all objects project onto exactly corresponding, identical points on both retinas.

correspondence problem

The two retinal images are slightly different. The visual system must correctly "correspond" or pair up points between the two images to extract depth information.

percieved state is determined by

angular size, percieved depth

angular size

the visual angle an object subtends in the observer's field of view.

size constancy

phenomenon where an object’s apparent size does not depend on it’s physical distance. observer needs to consider both size of retinal imae and distance of object s = k x (rxd)

size illusions

caused by causing people to mistake the distance to an object so that it appears larger or smaller than it really is eg. ames room