270 likes | 419 Views
VE Input Devices(I). Doug Bowman Virginia Tech Edited by Chang Song. Goals and Motivation. Provide practical introduction to the input devices used in VEs Examine common and state of the art input devices look for general trends spark creativity Advantages and disadvantages
E N D
VE Input Devices(I) Doug Bowman Virginia Tech Edited by Chang Song
Goals and Motivation • Provide practical introduction to the input devices used in VEs • Examine common and state of the art input devices • look for general trends • spark creativity • Advantages and disadvantages • Discuss how different input devices affect interface design
Input devices • Hardware that allows the user to communicate with the system • Input device vs. interaction technique • Single device can implement many ITs
ITs Human-computer interface User interface software Input devices System Software Output devices User
Human-VE interface Env. model Display(s) Simulation loop: -render -check for events -respond to events -iterate simulation -get new tracker data Tracking system Input device(s)
Input device characteristics • Degrees of Freedom (DOFs) & DOF composition (integral vs. separable) • Range of reported values: discrete/continuous/hybrid • User action required: active/passive/hybrid • Intended use: locator, valuator, choice, … • Frame of reference: relative vs. absolute • Properties sensed: position, motion, force, …
Practical classification system • Desktop devices • Keyboards, • 2D mice and trackballs, • pen-based tables, • joysticks, • 6DOF devices for the desktop • Tracking devices • 3D mice • Special-purpose devices • Direct human input
Desktop devices: keyboards • Chord keyboards1 • Arm-mounted keyboards2 • “Soft” keyboards (logical devices)
Desktop devices: 6-DOF devices • 6 DOFs without tracking • Often isometric • Exs: Fig. 4.4 SpaceBall 5000, SpaceMouse Plus, SpaceOrb
Tracking Devices • Motion tracking • Eye tracking • Data Gloves
Motion Tracking • Critical characteristics • Range, latency, jitter (noise or instability), and accuracy • Different motion trackers • Magnetic • Mechanical • Acoustic • Inertial • Optical • Hybrid
Electromagnetic trackers • Exs: Polhemus Fastrak, Ascension Flock of Birds • Most common • Used with conventional monitors (for fishtank VR) Small workbench displays • Transmitter • Receiver(s) • Noisy • Affected by metal objects -> distort the magnetic field
Inertial trackers • Inertial measurement devices : angular gyroscopes & linear accelerometer • Exs: Intersense IS-300, Intertrax2 • Less noise, lag • Only 3 DOFs (orientation)
Reflected or emitted light Exs: Vicon, HiBall, ARToolkit Advantages accurate can capture a large volume allow for untethered tracking Disadvantages may require light emitting diodes(LEDs) image processing techniques occlusion problem Optical/vision-based trackers
Outside-in or inside-out system Sensors/landmarks – tracked objects/environment Setting up vision-based tracking system can be difficult Optical/vision-based trackers
Hybrid tracking • Ex: IS-600 / 900 • inertial (orient.) • acoustic (pos.) • additional complexity, cost
Tracking devices: eye tracking • User controlling a mouse pointer strictly with his eyes. • Gazed direction based • Head-tracker as an approximation to where the user is looking. Problem can occur. • Improve these gaze-directed techniques
Tracking devices: bend-sensing gloves • CyberGlove7, 5DT • Reports hand posture • Gesture: • single posture • series of postures • posture(s) + location or motion
Tracking devices: pinch gloves • Conductive cloth at fingertips • Any gesture of 2 to 10 fingers, plus combinations of gestures • > 115,000 gestures
Case study: Pinch Gloves • Pinch gloves are designed to be a combination device (add a position tracker) • Very little has been done with Pinch Gloves in VEs - usually 1 or 2 gestures for: • Object selection • Tool selection • Travel
Characteristics of Pinch Gloves • Relatively low cost • Very light • User’s hand becomes the device • User’s hand posture can change • Allow two-handed interaction • Huge number of possible gestures
Characteristics of Pinch Gloves II • Much more reliable than data gloves • Support eyes-off input • Can diminish “Heisenberg effect” • Support context-sensitive gesture interpretation
Pinch Gloves in SmartScene13 • Lots of two-handed gestures • Scale world • Rotate world • Travel by “grabbing the air” • Menu selection
Pinch Gloves for menus • TULIP system14 • ND hand selects menu, D hand selects item within menu • Limited to comfortable gestures • Visual feedback on virtual hands
Pinch Gloves for text input • Pinch Keyboard14 • Emulate QWERTY • Pinch finger to thumb to type letter under that finger • Move/rotate hands to change active letters • Visual feedback
Combining Bend-Sensing Data and Pinch Input • Both the Pinch Gloves and bend-sensing gloves have limitations • The Flex and Pinch input system is an example of an input device that combines the functionality of the Pinch Gloves system with the bend-sensing technology of a data glove • Figure 4.15