369 Depth Perception

66 cards

final exam

Created Apr 10, 2012
by gialam92

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	Side A	Side B
1	3 reasons to have depth perception	- detection - discrimination - identification
2	why is depth perception difficult	- the world is 3D (our initial visual representation is 2D but somehow we recover the 3D (depth))
3	how do we see depth?	cues helps us solve the problem
4	types of cues for depth and distance	- monocular- binocular
5	6 types of static (pictorial) cues	- occlusion - ariel (atmospheric) perspective - linear perspective - texture -...
6	Closer objects partly block the view of more distant objects	occlusion
7	how does occlusion enable us to a perception of depth?	–you see the occluding object as closer than the occluded object).
8	–also enables us to complete and recognize objects.	occlusion
9	–is closely related to other perceptual phenomena such as transparency and...	occlusion
10	occlusion also is related to __ __	illusory contours
11	More distant objects are perceived less clearly than closer objects.	aerial perspective
12	–The further the light must travel to reach the eye, the ___ likely that...	less
13	–Aerial perspective sometimes is called ... ... because the effect...	atmospheric perspective
14	•Lines that are parallel in the real world appear to converge in a drawing.	linear perspective
15	–The greater the distance, the __ the convergence.	greater
16	Texture is more dense in a distant object than in an identical closer object.	texture gradients
17	if there is no variation in testure density, will depth be perceived?	no
18	an abrupt change in texture implies a ...	depth discontinuity (a sharp bend)
19	–counteract the effects of shading. For example, fish are lighter on their...	counter -shading
20	–In perceiving depth from shading, we make certain default assumptions...	lighting
21	•defined retinally, not environmentally (i.e., the light seems to come from...	"above"
22	The "___ " of depth depends on the direction of the luminance gradient. Because we assume...	direction
23	•Smaller objects often appear to be more distant than identical larger...	size
24	–The link between size and perceived depth stems from the fact that as an...	decreases
25	Two objects of different retinal image size are at the same depth only if ...	they really differ in size.
26	–Depends on moving objects –objects change shape with movement and...	kinetic depth effect
27	–Objects at different distances (In terms of where we focus) from fixation...	motion parallax
28	–Motion parallax can be thought of a __ ___ ___	disparity across time
29	motion can be thought of a disparity across time by ...	–integrating information about slightly different views across time, you...
30	–You converge your eyes when looking at close objects you diverge to look...	convergence
31	–You accommodate more to focus on closer objects	accommodation
32	–The amount of convergence and accommodation can be used as cues for __...	absolute depth
33	to make use of binocular depth cues, an organism must have...	binocular visual field
34	a region of overlapping visibility for the two eyes	binocular visual field
35	•Different animals have different extents of binocular visual fields. In...	read
36	•Although humans have large binocular visual fields, each eye is getting...	retinal disparity
37	is the difference between the lateral position of object in the left...	•Retinal disparity
38	relative to the point of fixation	relative distance
39	binocular depth cues depends on ...	relative distance
40	binocular depth cues give us two pieces of info .	- sign - magnitude
41	farther than fixation	uncrossed disparity
42	crossed disparity	closer than fixation
43	•Farther than fixation -> called uncrossed disparity •Closer than...	sign
44	Large distance /difference in depth	large disparity
45	Small distance /difference in depth	small disparity
46	–imaginary plane where each object on the plane casts images on corresponding parts...	horopter
47	•Objects same distance from observer as fixation yield zero disparity	horopter
48	•Objects on the horopter cast images on __ points of both eyes	corresponding
49	what does disparity do for us?	•Disparity is a geometric fact -- resulting from the fact that both eyes...
50	Do we all have stereopsis	•NO!! There are great individual difference in stereovision abilities. Some...
51	What did Barlow, Blakemore and Pettigrew find?	that cells in the cortex of the cat that respond best to stimuli that fall on...
52	What did Hubel and Weisel find?	•these cells in the visual cortex of monkeys and they identified them as...
53	•An object can look the same size at different distances But: retinal image...	perception of size and depth perception
54	an increase distance =	decrease retinal image size
55	a decreasing distance =	increase retinal image size
56	The fact that an object can look the same size regardless of changing retinal...	size constancy
57	•The fact that we have size constancy means that perceived size depends...	read
58	• •We seem to take __ __ into account as well.	perceived distance
59	This link between perceived size and perceived distance	size-distance scaling
60	We can formalize the notion of size-distance scaling in terms of ..	Emmert's law
61	S = R x D	Emmert's law
62	what else helps to perceiving size	relative size cues - familiar sources help
63	When perceptual cues are present then perception is	- accurate- verdical
64	When perceptual cues are not present then perception is	perceived as illusions (this is called Muller-Lyer illusion)
65	one possible explanation for the Ames Room	- size distance scaling
66	Apparent Depth: The horizon contains depth information, the sky does not	moon illusion