Ultra Low Latency Virtual Reality

Sebastian Friston sebastian.friston.12@ucl.ac.uk

Virtual Environments, Imaging and Visualisation

UCL Computer Science

Latency in VR

Latency in VR

The Importance of Interaction for Presence

The Sensorimotor Loop

Studying Latency

There are some complications…

1. No-one has a VR system with zero latency

2. Latency (may) affect senses differently

3. Latency (may) affect cognitive functions differently

4. Probing the user’s internal state is hard

5. ‘Latency’ doesn’t have a single value

Studying Latency

Measure Outcomes

• Is the user behaving

like its real?

• Have they learnt what

they are meant to

learn?

• Are they enjoying

themselves?

Measure Fidelity

• How closely does the

virtual stimuli match

ideal stimuli?

Low Latency Dataflow Renderer

Our System

Novel Image

Generator:

~1 ms

Our System

DK2 Display:

0-13 ms

Low Latency Dataflow Renderer:

Dataflow Computing

Low Latency Dataflow Renderer:

Environment Map Renderer

Low Latency Dataflow Renderer:

Architecture

Low Latency Dataflow Renderer:

Latency

Low Latency Dataflow Renderer:

Evaluation

Summary of sensitivity to velocity of linear models

for all four test conditions

DFE 1ms GPU 1ms DFE 13ms GPU 13ms

Normalised Root Mean Square Error

Velocity 1.01 1.089 1.008 1.531

R2 0.434 0.449 0.296 0.383

Spearman's Rank Correlation Coefficient

Velocity 0.039 -0.144 -0.49 -0.802

R2 0.192 0.215 0.436 0.481

Visual Information Fidelity

Velocity -0.033 -0.715 -0.41

R2 0.155 0.142 0.236 0.108

Present of Latency: Predictive Warping

Future of Latency: Cascaded Image Warping

• (Lincoln et al., Zheng et al.)

Future of Latency: Ambient Fields

• (Steed et al.)

Conclusion

• Our understanding of latency is not

comprehensive…

• …but we know it has an effect

• When in doubt: go low

• Test against intended outcomes

• Test against known priors

• Thank you! Any questions?