Unit 1_9
Human Computer Interface
Why have an Interface?
The user needs to issue instructions
Problem diagnosis
The Computer needs to tell the user what
to do
What do you need to Think about?
When designing an HCI you need to
consider:
Task
User experience
User preference
Resources
General Features
Appropriate input methods
Use of colour
Consistency
Pictures/Icons
Text
Sound
Types of HCI
Command Line
Graphical user interfaces
Menu driven interfaces
Form driven interfaces
Natural language interfaces
Voice control
Graphical devices
Game playing
Touch sensitive screens
Biometric
Command Line
When computers were first created the
lack of graphical abilities meant that all
user interfaces were command line
based.
Command Line
Advantages
Quicker that using a GUI for some tasks
More control for the user
Disadvantages
Very difficult for beginners
Have to remember loads of commands
Have to be very careful of syntax
EXAMPLE
Graphical User Interface
Graphical user interfaces utalise graphics in
order to code commands with pictorial
representation.
WIMP (Windows, Icon, Menus, Pointers)
Drag and drop
Task bars
WYSIWYG
Examples include Windows, LINUX, Snow
leopard
EXAMPLE
Graphical User Interface
Advantages
No need to learn commands
Icons mean that novices can use the
system
The use of a mouse
Disadvantages
Needs more powerful computers
More memory is needed
Can be confusing using icons (undo)
Menu Driven Systems
Use a restricted list of commands that the user can
select
Advantages
Fewer options mean less likely to make data entry
errors
Easy systems to understand and use
Context sensitive help can be provided
Unsuitable choices can be hidden from the user
Disadvantages
Only really suitable for systems that have a few
possible options
Causes frustration for experienced users
EXAMPLE
Form Driven Systems
Used to collect information from the user.
Advantages
Validation checks can be applied
Essential information can be forced
(presence check)
Disadvantages
Only really has one purpose, gathering
information from users.
Natural Language Interface
Allows users to use their own spoken language
to communicate with the computer. Via
microphone or keyboard.
Advantages
Very easy to learn
Disadvantages
Computers have real problems interpreting
natural language (context, dual means etc)
Voice Interfaces
Uses voice recognition software to implement
commands or input text onto a computer
Advantages
Faster than typing
99% accuracy
Cheap
Disadvantages
Needs training
Not accurate at first
Errors due to background noise
Not compatible with all software
The reverse is called speech synthesis
Graphical Devices
The tablet and pen system (have a look
at the interactive board). Great for
drawing or fine detail work. E.g. graphics
or CAD
Game Playing Devices
Joystick
Cordless games controller
Steering wheel
Car pedals
Gear sticks
Touch Sensitive Screens
Allows a user to make selections by
simply pressing options presented on the
screen. (The most famous example to
date is the itouch or iphone!). Great for
menu driven systems!
Biometric Devices
Retina Scan
Fingerprints
Hand prints
Voice
Face
EXAMPLES