color perception - Answers determined by the wavelength of light reflected from or emitted by an object
perception of color - Answers is purely psychological (wavelengths are physical)
hue - Answers variations described by names such as red, purple, blue, orange, etc
saturation - Answers apparent purity, vividness, or richness
lightness - Answers dark to light
trichromatic theory - Answers - human color vision is trichromatic
- there are three types of photoreceptors corresponding to blue, green, and red
- supported by the fact that there are three types of cones in the retina
colorblindness - Answers type one: dichromats
type two: two types of cones that work normally, one type that works weakly
how common is colorblindness? - Answers 1/12 men and 1/200 women
what colors are most affected with colorblindness? - Answers red and green
opponent process theory - Answers color perception is controlled by the activity of two opponent
systems (blue-yellow and red-green); only one color can be signaled at a time
opponent process theory (2) - Answers staring a red image produces a green afterimage
why do colors matter in HF? - Answers - many systems convey information via color
- we must create/evaluate displays based on how people perceive color
- displays can be useable or unuseable by people with colorblindness
how to accommodate colorblindness - Answers - select colors carefully
- test color display works for common colorblindness
- use redundant coding (using codes other than colors to convey information)
visual acuity - Answers clearness or sharpness of vision (usually measured by Snellen Eye Chart)
contrast sensitivity - Answers the ability of the VISUAL SYSTEM to distinguish bright and dim
components of a static image (function of both contrast and spatial frequency); declines with age
what do we see? - Answers what our eyes take in is distinct from what we actually perceive; our brain
has to organize the information we gather
, perceptual organization - Answers the process by which we figure out the relationships among
potentially separate stimulus elements
Figure v. Ground - Answers how we perceive objects and background
Gestalt - Answers essence or shape of an entity's complete form
Proximity - Answers elements close together are perceived as a group
Similarity - Answers similar elements (in terms of color, form, or orientation) are perceived together
Continuity - Answers points connected in straight or smoothly curving lines are perceived together
Closure - Answers open curves are perceived as complete forms
Common fate - Answers elements moving in the same direction at the same speed are perceived as
together
Artificially induce grouping - Answers forcibly grouping objects using non-Gestalt principles
Common region - Answers an explicit boundary
Connectedness - Answers explicit lines
Depth perception - Answers translate physiology and a 2D image on the retina into 3D spatial
information
proprioception - Answers ability to feel what your muscles are doing and where your limbs are
positioned (provides oculomotor depth cues)
accommodation - Answers automatic adjustments of the lens that maintain a focused image on the
retina
vergence - Answers degree to which the eyes are turned inward to maintain fixation on an object (good
up to 6m)
monocular depth clues - Answers pictorial cues; convey impressions of depth in a still image
interposition - Answers nearer objects will block the view of more distant objects if they are in the same
line of vision
size - Answers the bigness of an object; familiar cue (if you are familiar with how big an object is
supposed to be) and relative cues (based on size of other objects in view)
perspective - Answers angles such as when you know something is rectangular but it appears trapezoidal
motion parallax - Answers apparent displacement or difference in position of an object viewed along
two different lines of sight