3/23/2005 © Dr. Zachary Wartell 1 “ The Effect of Interocular Distance upon Operator Performance using Stereoscopic Displays To Perform Depth Tasks ” Louis B. Rosenberg Proceedings of IEEE Virtual Reality Annual International Symposium 93, Sept. 1993, pg Presentation: Revision 1.0

3/23/2005 © Dr. Zachary Wartell 2 Introduction General Goal: reproduce depth cues in telepresence and virtual environments (occlusion, shading, texture gradient, perspective, stereopsis) Question: how does artificial stereopsis enhance or detract from operator performance in tasks requiringdepth perception?

3/23/2005 © Dr. Zachary Wartell 3 Previous Results Kama64,Rupert73, Freedman77, Pepper81: –stereopsis is not a significant performance advantage in teleoperator systems Pepper88, Pepper83, Kim85, Ellis85: –stereopsis is a significant performance advantage in teleoperator systems

3/23/2005 © Dr. Zachary Wartell 4 New Experiment: To gain insight into this issue, compare operator performance results over range of modeled eye separation, covering: –monocular display to –exaggerated binocular display

3/23/2005 © Dr. Zachary Wartell 5 Under-estimated Modeled E.S. → Compression true modeled

3/23/2005 © Dr. Zachary Wartell 6 Over-estimated Modeled E.S. → Expansion true modeled

3/23/2005 © Dr. Zachary Wartell 7 Virtual Peg Alignment Task

3/23/2005 © Dr. Zachary Wartell 8 Experimental Protocol computer randomly places target peg user uses mouse to align control peg –no time limit –user presses mouse button to indicate completion Recorded: –target and control peg position –task completion time –modeled eye separation IV: m.e.s DV: task completion time

3/23/2005 © Dr. Zachary Wartell 9 Experiment Protocol (cont.) 9 subjects, 90 trials per subject Seated 80+/- 4 cm from screen all subject test on same distribution of (target location,m.e.s.) combinations modeled e.s. varys in [0,8] cm randomize presentation of target location and m.es. subject’s not informed of m.e.s. per trial nor that m.e.s. is varying!

3/23/2005 © Dr. Zachary Wartell 10 Experimental Protocol (cont.) Depth cues –perspective correct size –some linear perspective (note, no texture gradient or grid of lines) –height relative to horizon –shading (note, no shadows) –stereopsis

3/23/2005 © Dr. Zachary Wartell 11 Results

3/23/2005 © Dr. Zachary Wartell 12 Discussion errors drops with larger m.e.s. m.e.s. = 0 cm → error 10 times greater than m.e.s. = 6 cm sub’s report size variation cue important stereopsis enhances performance even with other depth cues! log function fits data with R 2 =0.975 Note: –error drops dramatically as m.e.s goes from 0 to 2 cm –m.e.s. greater than 3 cm don’t yield further task performance gains

3/23/2005 © Dr. Zachary Wartell 13 Conclusion Stereoscopic display vs monoscopic display yielded 10 fold reduction in mean error Since m.e.s. must be limited for fusibility and comfort issues, the finding that 3cm maximizes performance is significant –what about generality of this result? to other tasks to same task with texture gradiant or motion parallax or grid of lines or shadows how do results vary with modeled object distance?