Final Notes Flashcards
What 2 things can visual angel tell you about?
1) size of object
2) depth
(3) motion based cues
1) relative motion/motion parallax
2) accretion/deletion
3) motion in depth
Motion parallax
- stuff closer to you that fization point looks like it’s moving backwards
thing behing the fixation point are oging in same direction as you
accretion/deletion
accretion - gorwing/uncovering
deletion - being covered up
motion in depth
as something comes closer to you it gets better = looming vs. something that gets smaller as it becomes further away
- innate in babies
Binocular depth cues (sterodepth)
- L and R eyes see things diff. for bincoular disapirty
- this depth perception is really important
Steroscope
- 2 flat images become a 3d images so they look like diff. messages
depth information derived from stereposis vis 2 stages
1) solving the stero correspondance problem
2) calculating the retinal disparity
step one of depth: solving the sterocorrespondance problem
- matching the R and L eye in retina
- tricky because you are trying to match everything (can match random stimuli)
auto-stereogram
- illusions caused when we solve stero-correspondance problem incorrectly (3d image will appear )
- you match the R and L image wrong and then there is incorrect calucation of depth
stage 2 of cacluating depth: calculating the retinal disparity
- once you find the matching retinal images from R and L eye you need to see how different these images are in the L and R eye = retinal/binocular disparity
Retinal/binocular disparity
how different is the object position on the left and right eye
horopter
fixation plane - where it is you are looking
3 possibe outcomes of the retinal dispairty
1) zero disparty
2) crossed disparity
3) uncrossed disparity
zero disparity
- thereis no different in the point in the 2 eyes (light is on the same place in retin)
crossede dispairty
- object is closer to person and in front of the horpoter and light will fall on opposite parts of the eyball and reference point
uncrossed dispairty
- object is behind the horpoter and the light image is not on the same point in both eyes but it is on the same point of the reference point
Pannum’s fusion area
- area that is the limited range for binocular cues of you will see double images if it is too close or too far from heropter
- you an fuse the image from L and R eye to see 3D (when you thumb close to you eye you will see doubles)
Tilt after effect observation
the tilt effect still works even if you adapt one eye and close the other - tilt after effect crosses over to the unadapted eye
- happens because of bincoular cells in the straite cortex (take infro from both eyes = doesn’t matter what eye you use becuase it is the same cell) - cells in straite that are specailized for bincoluar depth
disaprtiy sensitive cells in the visual cortex
- cells can respond to certain disparities (movement in either direction e.g. 0 disparity, looking for specific difference from L and R eyes position)
Strabismus
- related to the msucles that control ocular movement; kids are born with imblance in eye
- can’t do steroimage matching so brain can’t deal with 2 diif. images so suppress one
- if not solved by 6 years old will not develop depth percpetion
Critical period
if no experiences = no development of bincoular cells (only have monocular cells)
Amblyopia
lazy eye - ignoring inform from one eye causes other to not track information anymore (sometimes caused because 1 eye is far/near signed so brain is having trouble bringing 2 eyes to coordination (no depth perception)
- no depth perception if not fixed by 6 years
Bincoluar rivlary
2 diff. images