  Virtual and augmented reality (VR/AR) displays strive to provide a
resolution, framerate and field of view that matches the perceptual
capabilities of the human visual system, all while constrained by limited
compute budgets and transmission bandwidths of wearable computing systems.
Foveated graphics techniques have emerged that could achieve these goals by
exploiting the falloff of spatial acuity in the periphery of the visual field.
However, considerably less attention has been given to temporal aspects of
human vision, which also vary across the retina. This is in part due to the
lack of a unified eccentricity-dependent spatio-temporal model of the visual
system. Here, we introduce the first such model, experimentally measuring and
computationally fitting a model of critical flicker fusion. In this way, our
model is unique in enabling the prediction of temporal information that is
imperceptible for a certain spatial frequency, eccentricity, and range of
luminance levels. We validate our model with an image quality user study, and
use it to predict potential bandwidth savings 7x higher than those afforded by
current spatial-only foveated models. As such, this work forms the enabling
foundation for new temporally foveated graphics techniques.
