Week 9 Flashcards
What is Euclidian Geometry?
- Parallel lines remains parallel as the extend in space.
- objects same Space size and shape
- images in the retina are non-euclidean
What is binocular summation?
The combination of signals from each eye in ways that make performance on tasks better
What is binocular disparity?
The differences between the two retinal images of the same scene
What are depth cues and the two types?
Information about the 3D space
- Monocular: world viewed with one eye
- Binocular: world vied with both eyes
Monocular depth cues properties?
Occlusion Size and portion aerial perspective Linear perspective motion parallax the eye
What is occlusion?
a cue to relative depth order in which one objects obstructs the view of another
There are two types of depth cues in monocular vision. what are they?
Metrical: provides quantitative info about distance and 3D
Non-metrical: Provides info about the depth order
What are the different size and portions of monocular depth cues?
- Relative size: Size between items (how close and item is
- Relative hight: Below horizon = closer / Above horizon = Further
- Texture gradient: based on geometric fact that items of the same size form smaller images when further away
What is aerial perspective?
depth cue based on the implicit understanding that light is scatted by the atmosphere
What is linear perspective?
Lines that are parallel in 3D will appear to converge
What is a vanishing point?
The apparent point at which parallel lines receding in depth converge
What are motion cues or motion parallax?
Images closer to the observer move faster across the visual field? (relative)
What are three properties of the eye itself?
Accommodation: eye change focus
Convergence: eyes to turn inwards (near object)
Divergence: eyes turn outwards (far objects)
What are corresponding retinal points
Points on the retina of each eye where the monocular retinal images of a signal object are formed are a there same distance from the fovea in each eye
What is binocular disparity?
difference between the two retinal images of the same scene
What is the horopter?
The location of objects whose images lie on the correspond points (zero disparity)
Whats the Vieth-Müller circle?
surface of zero disparity or location of objects whose images fall on geometrically corresponding points in eyes
Objects on the horopter are …
seen as single images when views with both eyes
What is the Panum’s fusional area?
the region of space in-front and behind the horopter.
Objects closer and futher away from the horopter:
Fall on non corresponding points in the two eyes and are seen as two images.
What is diplopia ?
Double vision. if visible in both eyes.
What is crossed disparity?
disparity created by the object in front of the place of horopter
Image displaced left in the right eye vice versa
What is uncrossed disparity?
disparity created by the object behind the plane of horopter
image displaced right in the right eye vice versa
What is free fusion?
The technique of converging or diverging the eyes in order to view a stereogram without a stereoscope
What is Stereoblindness?
An inability to make use of binocular disparity.
What is Correspondence problem?
Figuring out which bit of the image in the left eye should be matched up with which bit in the right eye
What are some ways to solve the correspondence problem?
Bluring the image: Reducing number of features
Uniqueness constraint: object featured once in each retina
Continuity constraint: disparity at neighbouring point should be familiar.
How is stereopsis implemented in the human brain?
zero disparity
tuned to particular binocular disparity
What is binocular rivalry?
competition between the two eyes for control of visual perception
In humans, evolution may have favored two eyes facing forward because it statistically increases the chance of detecting a stimulus. The combination of signals from the two eyes that enhances performance on many tasks is called:
Binocular summation
Using the depth cue of _______ you can tell how far away something is based on how much detail is visible in the elements on the ground between you and the object.
Texture gradient
Suppose you are looking at a road that recedes into the distance. Which depth cue describes the way the edges of the road seem to converge in the retinal image?
Linear perspective
When an artist paints trees on a landscape extending into the distance, she distributes the trees vertically to simulate _______, and makes trees that are farther away smaller, simulating _______.
Relative height; relative size
When driving in a car, the fact that light posts by the side of the road move faster across your eye than do distant buildings is the visual cue known as:
Motion paralax
The difference between crossed disparity and uncrossed disparity is that crossed disparity involves objects that are _______ the plane of fixation, while uncrossed disparity involves objects that are _______ the plane of fixation.
in front of; behind
