1. Effects of Handling Real Objects and Avatar Fidelity on Cognitive Task Performance in Virtual Environments Benjamin Lok University of North Carolina at Charlotte Samir Naik Disney VR Studios Mary Whitton, Frederick P. Brooks Jr. University of North Carolina at Chapel Hill March 25 th, 2003

2. Current Immersive VE Approaches System has limited shape and motion information of real objects. Most objects in the VE are purely virtual –User –Tools –Parts Most virtual objects are not registered with a corresponding real object.

3. Ideally Would like: –Real objects in the VE, including accurate virtual representations, or avatars –Virtual objects responding to real objects –Haptic feedback –Correct affordances –Constrained motion Example: Unscrewing a virtual oil filter from a car engine model

4. Dynamic Real Objects By tracking and modeling dynamic objects (change shape and appearance) would –Improve interactivity –Enable visually faithful virtual representations

5. Previous Work: Incorporating Real Objects into VEs Non-Real Time –Virtualized Reality (Kanade, et al.) Real Time –Image Based Visual Hulls [Matusik00, 01] –3D Tele-Immersion [Daniilidis00] Augment specific objects for interaction –Doll’s head [Hinkley94] –Plate [Hoffman98] How important is to get real objects into a virtual environment?

6. Previous Work: Avatars Self - Avatars in VEs –What makes avatars believable? [Thalmann98] –What avatars components are necessary? [Slater93, 94, Garau01] VEs currently have: – Choices from a library – Generic avatars – No avatars Generic avatars > no avatars [Slater93] Are visually faithful avatars better than generic avatars?

7. Object Reconstruction System System takes n live camera images. At each frame, generates a view of the visual hull of the real objects from the user. It is combined with the virtual environment 15-18 fps Allows incorporation of dynamic real objects into a virtual environment

8. Spatial Cognitive Task Study

9. Study Motivation Effects of –Interacting with real objects –Visual fidelity of self-avatars On –Task Performance For spatial cognitive manual tasks

10. Spatial Cognitive Manual Tasks Spatial Ability –Visualizing a manipulation in 3-space Cognition –Psychological processes involved in the acquisition, organization, and use of knowledge

11. Task Performance Hypotheses Real Objects: Participants will complete a spatial cognitive manual task faster when manipulating real objects, as opposed to virtual objects only. Avatar Fidelity: Participants will complete a spatial cognitive manual task faster with visually faithful self-avatars, as opposed to generic avatars.

12. Task Manipulated identical painted blocks to match target patterns Each block had six distinct patterns. Target patterns: –2x2 blocks (small) –3x3 blocks (large)

13. Measures Task performance –Time to complete the patterns correctly –If errors were made: Participants were notified Participants continued until all errors were corrected Other factors –(After experience) Steed-Usoh-Slater Sense of Presence Questionnaire (SUS) (larger study) –(Before experience) spatial ability –(Before and after experience) simulator sickness

14. Conditions All participants did the task in a real space environment. Each participant did the task in one of three VEs. Real Space Purely Virtual Hybrid Vis. Faithful Hybrid

15. Conditions Avatar Fidelity Generic Visually faithful Interact with Real objects HEVFHE Virtual objects PVE Task performance

16. Real Space Environment Task was conducted within a draped enclosure Participant watched monitor while performing task RSE performance was a baseline to compare against VE performance

17. Purely Virtual Environment Participant manipulated virtual objects Participant was presented with a generic avatar

18. Hybrid Environment Participant manipulated real objects Participant was presented with a generic avatar

19. Visually-Faithful Hybrid Env. Participant manipulated real objects Participant was presented with a visually faithful avatar

20. Task Performance Results Small Pattern Time (seconds)Large Pattern Time (seconds) MeanS.D.MeanS.D. Real Space (n=41)16.86.337.29.0 Purely Virtual (n=13)47.210.4117.032.3 Hybrid (n=13)31.75.786.826.8 Visually Faithful Hybrid (n=14)28.97.672.316.4

21. Small Pattern TimeLarge Pattern Time T-testp p Purely Virtual vs. Vis. Faithful3.320.0026**4.390.00016*** Purely Virtual vs. Hybrid2.810.0094**2.450.021* Hybrid vs. Vis. Faithful Hybrid1.020.322.010.055 * - significant at the  =0.05 level ** -  =0.01 level *** -  =0.001 level Task Performance Results

22. Debriefing Responses They felt almost completely immersed while performing the task. They felt the virtual objects in the virtual room (such as the painting, plant, and lamp) improved their sense of presence, even though they had no direct interaction with these objects. VFHE and HE participants felt tactile feedback of working with real objects improved their performance and sense of presence. They felt that seeing an avatar added to their sense of presence. PVE and HE participants commented on the fidelity of motion, whereas VFHE participants commented on the fidelity of appearance. VFHE participants reported getting used to manipulating and interacting in the VE significantly faster than PVE participants.

23. Conclusions

24. Study Conclusions Interacting with real objects provided a quite substantial performance improvement over interacting with virtual objects for cognitive manual tasks. Avatar fidelity does not appear to affect cognitive task performance. Handling real objects makes task performance and interaction in the VE more like the actual task.

25. Future Work Improved Object Reconstruction System –model fidelity –lag and latency (could improve results) Further studies to illuminate: –Effect of real objects and avatar fidelity on: Sense of Presence –Expand on the relationship between avatar kinematic fidelity and visual fidelity

26. Thanks Collaborators Dr. Larry F. Hodges UNC-CH Effective Virtual Environments Object Reconstruction System I3D2001 and I3D2003 For more information: http://www.cs.uncc.edu/~bclok/research/vr2003 Funding Agencies The LINK Foundation NIH (Grant P41 RR02170) National Science Foundation Office of Naval Research