Latency Compensation for HeadMounted Virtual Reality

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Latency Compensation for Head-Mounted Virtual
Reality

• Jason Jerald
• Comp291
• November 25th, 2003

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Latency is bad

• Registration error
• Oscillopia
• Due to sensory conflict
• The world does not appear stable
• Cause of simulator sickness
• Degraded Visual Acuity
• Motion blurring in the wrong places
• Degraded Human Performance
• Humans cannot adapt to high latencies
• Consistent latency important
• How do latencies below 30 ms affect users?

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System Delay versus Latency

• System delay is the true end-to-end delay of a
  system

• cannot be completely removed

• Latency is defined to be the effective latency as
  perceived by the user

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Where does the error come from?

• Dynamic error
• Registration error due to latency
• Greater than all other error combined
• Orientation error worse than translational error
• Yaw orientation worse error due to user looking
  left/right quickly and frequently

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Proposed Method
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Proposed Method

• Reduce system delay and its variance
• Small enough to predict head motion
• Synchronization delay can be the largest and most
  difficult to analyze / reduce
• Orientation prediction
• Using gyroscopes
• Render for the predicted pose
• 2D scanline shifts
• Corrects yaw prediction error at the last
  possible moment
• Performed in specialized hardware
• Just-in-time scanlines

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Results
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Results
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Results
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Future Work

• Currently building the proposed system
• Error Analysis
• Is the orientation prediction / correction good
  enough?
• If not then start over by reducing system delay
• What is the next largest source of error?
• Vertical Translations
• More difficult to correct
• Strange perceptual artifacts
• Translational prediction / correction
• Accelerometers
• 3D warp required for translation correction
• 3D warps cause artifacts
• User Studies
• To determine the threshold of latency perception