interaction with surfaces
DESCRIPTION
Interaction with Surfaces. Aims. Last week focused on looking at interaction with keyboard and mouse This week Surface Interaction Gestures. Surface. What do we mean by surface?. Touch Screens. Very durable – only input device to survive at Disney World Arm fatigue can be a problem - PowerPoint PPT PresentationTRANSCRIPT
Interaction with Surfaces
AimsLast week focused on looking at
interaction with keyboard and mouse
This week◦Surface Interaction◦Gestures
Surface
What do we mean by surface?
4
Touch ScreensVery durable – only input device
to survive at Disney WorldArm fatigue can be a problem
◦Tilt the screen (lighting)◦Surface to rest arms
Types of SurfacesLots of different types:
◦Resistive – two layers when press down they collide
◦Capacitive - layer that stores electrical charge, touches the monitor with his or her finger, some of the charge is transferred to the user
◦Surface acoustic wave system - two transducers and reflector can sense when wave has been disturbed
Modelling User InteractionWould be nice if you could
calculate the time required to point at an object.
7
Fitts’ Law (1954)Predictive Model of time required
to point at an object – nice formulae
Can determine optimal location and size of buttons
Time required to complete hand movement was dependant on the distance users had to move (D)
The target Size (W)
8
Fitts’ LawIf it took 2 seconds to select a
target that was 10 cm away might expect it to double if 20 cm away to 4 seconds not the case
Increasing size of the target from 1cm2 to 2cm2 enables users to point more rapidly
Start and Stop times are constantMT = a + b log2 (D/W+1)
9
Fitts Law and usersKnow your users!Fitt’s law well established for
adultsNeeds refinement for other users
such as children and elderlyAge can effect speed and
accuracy
Study performed using mouseRepeating action ofSelecting two
targets1= Young adults2= 5 year olds3= 4 year olds
Study performed using mouseRepeating action ofSelecting two targets1= Young adults2= 5 year olds3= 4 year olds
Juan Pablo Hourcade, Benjamin B. Bederson, Allison Druin, and Francois Guimbretiere. 2004. Differences in pointing task performance between preschool children and adults using mice. ACM Trans. Comput.-Hum. Interact. 11, 4 (December 2004), 357-386
Social InteractionEven with this knowledge design
for interaction problematic when you have multi-user interaction
Example multi-player games on large displays (Video)
From GUIs to NUIsNatural User InterfaceFocus on natural way of
interacting with devicesConcept around for long timeNewton Message Pad Apple 1989Hand writing recognitionAWFUL!
13
GesturesNatural ways to interactVision recognition used to
capture hand movement and gestures in front of a white board
Widely researched area in HCIWii Accelerometer based gesture recognition
State-Transition ModelDirect touch
Idle Active
Finger lands
Finger lifted
Finger moving in air
Finger moving on device
15
Gestures
The actual shape Filtered to interpret a circle
16
Gestures Shaking – basic note
entryTilting - subdividing
note durations in the stored sequence.
Tapping - tap for lower and higher notes.
Tossing – used to pass music to another deviceWeinberg, G., Godfrey, M., and Beck, A. 2010. ZOOZbeat: mobile music recreation. In Proceedings of the 28th of the
international Conference Extended Abstracts on Human Factors in Computing Systems (Atlanta, Georgia, USA, April 10 - 15, 2010). CHI EA '10. ACM, New York, NY, 4817-4822
17
GesturesIssues
◦Training usually required◦Remembering gestures = Gulf of execution
◦Nothing happens = Gulf of evaluation Need to understand cause movement
constraints are reached
◦No real standards – Apple defined gestures ?
◦Can programme your own
18
What’s this gesture?
19
What’s this gesture?
20
GesturesSurface established gestures
21
GesturesSurface user defined gestures
What about Fat FingersUser touches
device large part of finger contacts surface (system not realise it)
Can’t see the pixels that are being targeted – finger is in the way
Video
Gulf of CompetenceGulf occurs when
learn something one way and then have to relearn it another
For example mouse to keyboard shortcuts
Mouse to gesture interaction
24
Summary GesturesHow many could a child
remember?Would they need training?Is this part of the system or one
you created?Need to discuss issues for your
assignmentOne of major input methods to
consider