CCT: Lecture 5 10/11/2012 10:06:00 AM
Picture superiority effect
Theories of visual perception
Digitization of text
Fair-use, ebooks, and the death of newspapers
Contemporary communication technologies disrupt traditional business models
Contemporary communication technologies disrupt traditional legal definitions
Symbols, pictograms and icons are widely used components of user interfaces in ICT
applications and services e.g. navigation, status indication and function invocation.
Picture superiority effect
Pictures are more memorable than words
Pictograms: Images that represent a word; they are symbolic representations of an object or an
idea
Icons: A graphic on a visual display terminal that represents both functions (actions) and objects
on the computer system. Icons may represent a file, folder, application or device on a computer
operating system.
Well-designed icons and symbols can have the following advantages over written commands and
labels.
They can be:
More distinctive;
More efficient for denoting spatial attributes;
Easier to recognize and remember over long periods of time;
Easier and faster to learn when the size of the symbol set is small;
Language independent
Icons are time sensitive, culturally relevant, and poorly designed icons are highly
problematic.
Icons are NOT universal October 11, 2012
Five Guidelines for Good Icon Design
Simplicity: Apple Human Interface Guidelines (2008) recommend using one easily recognized
object, because the basic shape or silhouette of an icon can help users to quickly identify it.
Ziegler and Fähnrich (1988) also state that graphical symbols should be constructed with as few
graphical components as possible – usually not more than 2 or 3 components.
Text icon size with relevant user group: According to the ETSI (European Telecommunications
Standards Institute) standard 201 379 (1988), no general recommendation can be given on the
minimum acceptable size of an icon, this is because what is acceptable depends on a number of
parameters: (a) The user (b) Viewing distance between the user and the interface, ( c ) The
complexity of the symbol: (d) The display qualities of the medium including: the resolution, the
contrast, the focus and glare, (e) The viewing conditions including environmental factors such as
poor illumination, and (f) physiological and psychological factors such as fatigue and workload.
Shape: According to the ETSI standard 201 379 (1998), on some equipment, particularly small
machines, special manufacturing considerations or lack of space preclude the use of graphical
symbols of the exact recommended shape. In such cases, the design of the graphical symbols
used may be modified provided that their pattern differs as little as practicable and still conveys
clearly the intended meaning.
Color: An investigation by fennel (2006) into personal preference for the color contrast of icons
revealed a preference for the following color contrast option: black icons on a white button, with
a black surround.
The Apple Human Interface Guidelines (2008) recommend using color “judiciously to help the
icon tell its story”. Color should not be added just to make the icon more colorful and smooth
gradients typically work better than sharp delineations of color. Optimally 2-4 colors should be
used.
Position: The position of labels with text or icons is crucial for an unfamiliar user with impaired
vision.
All too often labels are positioned in a way that they are obscured from the user’s view when the
controls are being operated.
Both left handed use and right-handed controls should also be considered.
Theories of visual perception
Johannes Kepler and retinal image (1604) – discovered that retinal images are upside down, and
2 dimensional. October 11, 2012
Perceptual hypotheses (1940s) – Constructivists such as Hermann von Helmholtz – external
world cannot be directly perceived because of the poverty of the information in the retinal
images, we interpret the sensory data on the basis of stored knowledge acquired through
learning.
The ecological approach to perception (1950s) – James Gibson – information available in the
visual environment to an active observer provides information to the viewer.
The Gestalt school (1930s – present) – perception through neural isomorphism (a substance or
organism that exactly corresponds in form with another.) i.e. what we see reflects isomorphic
patterns in the brain.
The computational approach (1970s) – Vision seen as the process of forming a description of
what is in the scene from the retinal images.
How the eye works
The eye takes in the image and it’s upside down.
The brain makes sense of it.
Digitization of text
Definition: Any process by which information is captured in digital form, whether as an image,
textual data, as a sound file, or any other format.
Why digitize texts?
Page Image: A digital image of a page of text, captured by a scanner or digital camera, and
expressed as a set of pixels in a format such as JPEG or TIFF.
OCR: Optic
More
Less
