Chapter 6: Space Perception and Binocular Vision Flashcards
realism
A philosophical position arguing that there is a real world to sense
Positivism
A philosophical position arguing that all we really have to go on in the evidence of the senses, so the world might be nothing more than an elaborate hallucination.
Euclidean
Referring to the geometry of the world, so named in honor of Euclid. Parallel lines remain parallel as they are extended in space, objects maintain the same size and shape as they move around in space, the internal angles of a triangle always add to 180 degree etc…
binocular
with two eyes
binocular summation
The combination of signals from each eye in ways that make performance on many tasks better with both eyes than with either eye alone.
monocular
with one eye
stereopsis
The ability to use binocular disparity as a cue to depth.
depth cues
information about the third dimension (depth) of visual space. Depth cues may be monocular or binocular.
Monocular depth cue
A depth cue that is available even when the world is viewed with one eye alone.
binocular depth cue
A depth cue that relies on info from both eyes. Stereopsis is the primary example in humans, but convergence and the ability of two eyes to see more of an object than one eye sees are also binocular depth cues.
occlusion
A cue to relative depth order in which, for example, one object obstructs the view of part of another object.
nonmetrical depth cue
A depth cue that provides information about the depth order (relative depth) but not depth magnitude.
metrical depth cue
A depth cue that provides quantitative information about distance in the third dimension
projective geometry
To study 3D world, the geometry that describes the transformations that occur when the 3D world is projected onto a 2D surface. Ex: Parallel lines do not converge in the real world but they do in the 2D projection of that world.
Relative size
A comparison of size between items without knowing the absolute size of either one.
texture gradient
A depth cue based on the geometric fact that items of the same size form smaller images when they are far away. An array of items that changes in size smoothly across the image will appear to form a surface titles in depth.
relative height
As a depth cue, the observation that objects at different distances from the viewer on the ground plane will form images at different heights in the retinal image. Objects farther away will be seen as higher in the image.
familiar size
A depth cue based on knowledge of the typical size of objects like humans or pennies.
relative metrical depth cue
A depth cue that could specify, for example, that object A is twice as far away as object B without providing information about the absolute distance to either.
absolute metrical depth cue
A depth cue that provides quantifiable information about distance in the third dimension
Aerial perspective (or haze)
A depth cue based on the implicit understanding that light is scattered by the atmosphere. More light is scattered when we look through more atmosphere. More light is scattered when we look through more atmosphere. Thus, more distant objects are subject to more scatter and appear fainter, bluer, and less distinct.