Perception 3 Flashcards
What does visual input provide?
Ambiguous information about the 3D structure of the world
What does image complexity do for computers?
Makes it increasingly tricky for computers to organise the visual scene into distinct objects
What can we infer with Monocular cues (one eye)?
Relative height, relative size and shadows
What can we infer with Binocular cues (both eyes)?
Disparity
Where are objects if they are typically perceived as being more distant?
Below the horizon and have their bases higher
If two objects are of equal size the more distant one will take up more or less of your field of view?
Less
What happens to texture elements when distance increases?
They get smaller and more dense with distance
What happens to circles when the surface is tilted away?
Foreshortening (circles become ovals)
Define motion parallax
As we move, more distant objects will glide past us more slowly than nearer objects
What does the brightness of a surface depend on?
Its orientation with respect to the light source
Define stereoscopic vision
Our 2 eyes receive a slightly different image of the world
What does disparity do on image location?
It creates a difference in location of an object seen by left and right eyes
What does the size of the disparity depend on?
Object’s depth
What is a Horopter?
A set of points that project to corresponding positions in the 2 retinas
What disparities do objects have when they are closer than the horopter?
Crossed disparities
What disparities do objects have when they are further than the horopter?
Uncrossed disparities
What is the process where depth information is extracted from binocular disparities called?
Stereopsis
What is Structuralism?
Proposed by Wundt; perceptions are simply the sum of ‘atoms’ of sensation
What is the Gestalt school?
against structuralism led by Wertheimer, Köhler & Koffka; argued the whole form is greater than the sum of its parts
What are illusory contours?
Some images evoke the perception of edges in locations where there is no change in luminance or colour- this is hard to explain with the structuralist approach
What did the Gestalt psychologists propose?
Principles which elements in an image are grouped to create larger objects
Define proximity, in terms of visuals
Things that are close together group together
Define similarity, in terms of visuals
Things that are similar group together
Define common fate, in terms of visuals
Things that move together, group together
What helps preserve grouping of occluded objects?
Group elements to form smoothly continuing lines rather than abrupt/ sharp angles
Define closure, in terms of visuals
Group elements to form complete figures, even if incomplete
What makes elements more likely to be formed into groups?
If they are balanced or symmetrical
What is one limitation of the Gestalt principles?
Some are vague and there is no coherent workable account of the underlying neural mechanisms
