VISUAL PERCEPTION Flashcards
The process of knowing or being aware of information through the eyes.
Visual Perception
The process of acquiring, interpreting, selecting, and organizing sensory information.
Visual Perception
Applying methods of physics to measuring human perceptual systems.
Psychophysics:
: Understanding how people think. In this context, how it relates to perception.
Cognitive psychology
Visual System:
Light path
Cornea, pupil, lens, retina
Optic nerve, brain
Visual Systems
Retinal Cells
Rods and cones
Unevenly distributed
Generally produced by purpose built cameras, or computer applications, or drawings
Pictures
Some things seem to be done preattentively, without the need for focused attention. Generally take less than ____ msecs (eye movements take _____ msecs)
200-250
200
A ______ _____ represents that visual sensation that allows us to pre-attentively differentiate two adjacent, possibly structured parts in our visual field without eye movement
visual texture
to identify textures, an observations of about ____-____ms is sufficient (cognitively controlled processes require about ___-_____ ms)
160-200
300-400
improve perception of position and orientation
Texture
_____ communicate information about the 3D structure regardless of their coloring
Texture
fundamental micro-structures in generic natural images
-basic elements in pre-attentive visual perception
Textons
Textons can be classified into three general categories:
- elongated blobs
- terminators
- crossings of line segments
_____ believes that only a difference in textons or in their density can be detected pre-attentively
Julesz
When designing textures to indicate different regions of a visualization, make sure that the _____ are as different as possible
textons
Each of these target types can be classified as ___ or ____
friendly or hostile
3D display should provide ___ cues
depth
more distant objects become smaller in the image
can indicate focus, importance, or ordering
- elements of a uniform texture become smaller with distance
Linear Perspective
- show the relative height of objects above a surface
- provide strong depth cues for objects in motion
- can be semi-realistic and still work as a depth cue
Shadow
very powerful depth cue
Occlusion
(structure from motion) –> how objects relate under motion (see next slide for examples)
motion parallax
information visualization displays, one may ____ ____ to emphasize importance, despite depth relationships
exploit focus
Symbols should be rapidly ______ and ______
perceived; differentiated
Measured amount of light coming from some place
Luminance
Perceived amount of light coming from source
Brightness
CIELAB -
CIELUV -
(print)
(display)
____ (based on technology model)
____ (based on perceptual color model)
RGB
HSB (HVS) model
___ what people think of color
Hue
____ intensity, whiteness
Saturation
____ light/dark
Brightness (Value)
Surround matters, especially for colors
Successive Contrast
Color perception is ____
relative
We are sensitive to small differences- hence need ____ million colors when driving computer displays
sixteen
Not sensitive to absolute values- hence we can only use less than ___ or ____ colors for coding
10 or 12
Ordered values should be represented by _____ colors
perceptually-ordered
Separation: significantly different levels should be represented by ____ colors
distinguishable
: good for showing form
Luminance
Allows you to simulate what a colorblind person would see when viewing your image or website.
Vischeck by Bob Dougherty and Alex Wade.
____ (part of vischeck) will correct (suggest) alternative color scheme so colorblind person can appreciate detail in image (switch Red/Green use to other hues
Daltonize
Types of color scales
Continuous/Interval Data
Categorical Data
_____ Data use continuous color scale (mono/divergent)
Continuous/Interval
____ Data use labeling/qualitative color scale
Categorical
_______ by ______;for GIS maps, is very helpful for picking safe continuous/discrete scales, and the number of colors in scales. She avoids uses saturated colors, and developed diverging color scales.
Color Brewer Tool developed by Cynthia Brewer
_____ by ____ Allows you to easily visualize and modify/compare color scheme choices for several common (designer recommended) color palettes for interfaces
Color Scheme Designer by Petr Stanicek.
Generally don’t use ____ colors
complementary
If you want contrast, use nearly ____, or ______ analogic.
accented
Adobe’s ___ tool. Social media tool allowing you to save and share your color theme schemes, and to search and see others as well.
Kuler
____ and ____: to preserve univariate information, display parameters should should be perceptually orthogonal (ideally)
Rows and columns
Use ______ for detail, shape and form
luminance
Use color for _____ - few colors
coding
Strong colors for small areas - contrast in ____ with background
luminance
_____ colors can be used to segment large areas
Subtle
Luminance Channel
Detail
Form
Shading
Motion
Stereo
Chromatic channels
- Surfaces of things
- Labels
- Categories,Berlin and Kay (about 6-10)
- Red, green, yellow and blue are special (unique hues)
