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VE Input Devices Doug Bowman Virginia Tech
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
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 • Exs: Intersense IS-300, Intertrax2 • Less noise, lag • Only 3 DOFs (orientation)
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
Hybrid tracking • Ex: IS-600 / 900 • inertial (orient.) • acoustic (pos.) • additional complexity, cost
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
3D mice • Ring Mouse • Fly Mouse • Wand • Cubic Mouse • Dragonfly • …
Special-purpose devices: using conductive cloth • Virtual toolbelt • Used to select virtual tools • Good use of proprioceptive cues • Interaction slippers3 • Step on displayed options • Click heels to “go home”
Human input: speech • Frees hands • Allows multimodal input • No special hardware • Specialized software • Issues: recognition, ambient noise, training, false positives, …
More human input • Breathing device - OSMOSE • Brain-body actuated control • muscle movements • thoughts!
Treadmills Stationary cycles VMC / magic carpet Walking/flying simulations (use trackers) Locomotion devices
UNIPORT • First Locomotion Device For U.S. Army (1994) • Proof-of-concept demonstration • Developed in six weeks • Difficult to change direction of travel • Small motions such as side-stepping are impossible
Treadport • Developed in 1995 • Based on a standard treadmill with the user being monitored and constrained by mechanical attachment to the user’s waist • User actually walks or jogs instead of pedaling • Physical movement is constrained to one direction
Individual Soldier Mobility Simulator (Biport) • Most sophisticated locomotion device • Designed for the conduct of locomotion studies • Hydraulic-based locomotion driven w/ force sensors at the feet • Safeguards limited responsiveness • Too awkward to operate
Omni-Directional Treadmill15,16 • Most recently developed locomotion device for U.S. Army • Revolutionary device that enables bipedal locomotion in any direction of travel • Consists of two perpendicular treadmills • Two fundamental types of movement • User initiated movement • System initiated movement
Virtual Motion Controller17 • Weight sensors in platform sense user’s position over platform • Step in direction to move that direction • Step further to go faster
Walking in place18,19 • Analyze tracker information from head, body, feet • Neural network (Slater) • GAITER project (Templeman) • Shown to be better than purely virtual movement, but worse than real walking20
Input and output with a single device • Classic example - touch screen • LCD tablets or PDAs with pen-based input • Phantom haptic device • FEELEX haptic device21
PDA as ideal VE device?22 • Offers both input and output • Has on-board memory • Wireless communication • Portable, light, robust • Allows text / number input • Can be tracked to allow spatial input
Conclusions • When choosing a device, consider: • Cost • Generality • DOFs • Ergonomics / human factors • Typical scenarios of use • Output devices • Interaction techniques
Acknowledgments • Joe LaViola, Brown University, for slides and discussions • Ron Spencer, presentation on locomotion devices used by the Army
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