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What is Virtual Reality? “A high-end user interface that involves real-time simulation and interaction through multiple sensorial channels.” (vision, sound,

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Presentation on theme: "What is Virtual Reality? “A high-end user interface that involves real-time simulation and interaction through multiple sensorial channels.” (vision, sound,"— Presentation transcript:

1 What is Virtual Reality? “A high-end user interface that involves real-time simulation and interaction through multiple sensorial channels.” (vision, sound, touch, smell, taste)

2 Immersive Computer generated images will replace the real world view The generated images will react to the position and orientation of the user’s head Non-Immersive Users are able to view the virtual world however, they are still aware of the real world i.e. viewing the VE through a monitor Hybrid Permits the user to view the real world with virtual images superimposed over this view Also known as augmented reality Type of VR systems

3 VR is an integrated trio of “Immersion”, “Interaction” and “Imagination”

4 reality-scent-human.html Let watch some images / clips &feature=relatedwww.youtube.com/watch?v=he5mZX1sRXk &feature=related

5 Input Devices: Trackers, Navigation and Gesture Interfaces

6 3-D System of coordinates of a VR object Virtual objects have 6 degrees of freedom (D.O.Fs): -three translations; -three rotations. Input Devices

7 Trackers measure the motion of “objects” such as user’s wrist or his head vs. a fixed system of coordinates. Technologies to perform this task: Mechanical trackers (special cases); Magnetic trackers (prevalent); Ultrasonic trackers (less used); Inertial/ultrasonic trackers (new). Vision-based trackers (new) Input Devices

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9 Tracker characteristics: Tracker characteristics: Measurement accuracy Measurement rate – Readings/sec; Sensing latency; Sensor noise and drift; Measurement repeatability; Tethered or wireless; Work envelope; Sensing degradation. Input Devices

10 Tracker characteristics: Tracker characteristics: Real object position Accuracy Resolution Tracker position measurements Input Devices

11 Tracker characteristics: Tracker characteristics: Real object fixed position Signal noise Time Tracker data Input Devices

12 Tracker characteristics: Tracker characteristics: Real object fixed position Sensor drift Time Tracker data Input Devices

13 Tracker characteristics: Tracker characteristics: Real object position Sensor latency Time Tracker data Input Devices

14 Mechanical Trackers Definition: A mechanical tracker consists of a serial or parallel kinematic structure composed of links interconnected by sensorized joints. Input Devices

15 Mechanical Trackers Pros Use sensors imbedded in exoskeletons to measure position; Have extremely low latencies; Are immune to interference from magnetic fields and large metal objects; Cons But limit the user’s freedom of motion; Can be heavy is worn on the body Input Devices

16 Exoskeleton structure Interface With computer Input Devices

17 Magnetic Trackers Definition: A magnetic tracker is a non-contact position measurement device that uses a magnetic field produced by a stationary TRANSMITTER to determine the real-time position of a moving RECEIVER element Input Devices

18 Magnetic Trackers Use low-frequency magnetic fields to measure position; The receiver is attached to the tracked object and has three perpendicular antennas; Distance is inferred from the voltages induced in the antennas.. Need calibration Input Devices

19 Polhemus Long Ranger tracking errors (Rutgers) Metal in lab double ceiling

20 Ultrasonic Trackers Definition: A non-contact position measurement device that uses an ultrasonic signal produced by a stationary transmitter to determine the real-time position/orientation of a moving receiver. Input Devices

21 Ultrasonic Trackers Use low-frequency ultrasound to measure position; Sound produced by a fixed triangular source (speakers); The receiver is triangular and attached to the tracked object and has three microphones; Distance is inferred from the sound time of flight; Sensitive to air temperature and other noise sources; Requires “direct line of sight”; Slower than magnetic trackers (max 50 updates/sec). Input Devices

22 Ultrasonic tracker (Logitech) Input Devices

23 Optical Trackers Definition: A non-contact position measurement device that uses optical sensing to determine the real-time position/orientation of an object Input Devices

24 Optical trackers: a) outside-looking-in; b) inside-looking-out Input Devices

25 Outside-looking in: Vicon MX Uses 4 Mpixel cameras with own 120 LED array (infrared, or visible red). Accuracy 0.02 of a pixel, Camera has real-time onboard image processing (masking and thresholding) Resolution 160 fps 8 cameras are connected to a MX net unit which then communicates with the PC

26 Input Devices Outside-looking in: Vicon MX MX Link connects several MX Net units for more cameras To interface with other devices like a force plate, sensing glove or eye tracker – use a MX control unit. User wears reflective markers (small spheres).

27 Inside-out optical tracker advantages The best accuracy is close to the work envelope. Very large tracking surface and resistance to visual occlusions (line of sight). Input Devices

28 Hybrid Ultrasonic/Inertial Trackers No interference from metallic objects; No interference from magnetic fields; Large-volume tracking; “Source-less” orientation tracking; Full-room tracking; A newer technology. Input Devices

29 InterSense Stereo Glasses tracker (courtesy of Intersense Co.) I-Cube Accel./gyro Ultrasonic emitter

30 InterSense Stereo stylus tracker (courtesy of Intersense Co.) Accelerometer Ultrasonic emitter

31 Navigation and Gesture Input Devices Navigation interfaces allow relative position control of virtual objects (including a virtual camera); Gesture interfaces allow dextrous control of virtual objects and interaction through gesture recognition. Input Devices

32 Navigation Input Devices Are the Cubic Mouse, the trackball and the 3-D probe; Perform relative position/velocity control of virtual objects; Allow “fly-by” application by controlling a virtual camera. Input Devices

33 The Cubic Mouse Input Devices VC 2.2 book CD

34 Trackballs Input Devices

35 The Microscribe (Immersion Co.) Input Devices

36 Gesture Input Devices Are sensing gloves such as: - Fakespace “Pinch Glove” - 5DT Data Glove; - The DidjiGlove - Immersion “CyberGlove” Need calibration for user’s hand. Input Devices

37 Finger Degrees of Freedom Input Devices

38 Hand work envelope vs. interface type Input Devices

39 The Pinch Glove (Fakespace Co.) - no joint measures, but contact detection

40 The glove interface: a) five-sensor version; b) newer design A) One optical fiber/finger Roll/pitch sensing 5DT Data Glove Ultra 5DT Data Glove 100 datasets/sec, 12 bit A/D flexion resolution, wireless version transmits data at 30 m, needs calibration

41 The glove interface: a) 14-sensor version; b) wireless kit Two sensors/finger plus abduction sensors 5DT Data Glove - continued Two gloves use one Bluetooth 2.4 GHz transmitter on the user’s belt

42 5DT Data Glove Input Devices


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