Perceptual versus Cultural
Architecture for visual thinking
Intro to Human Visual System and Displays Fundamental Optics Fovea The ultimate Display
Human Visual Field
Visual Angle
1 diopter: a lens that focuses at 1 meter. 45d ~15d
Acuities Vernier super acuity (10 sec) Grating acuity Two Point acuity (0.5 min)
Human Spatial Acuity
Cutoff at 50 cycles/deg. Receptors: 20 sec of arc Pooled over larger and larger areas 100 million receptors 1 million fibers to brain A screen may have 30 pixels/cm – need about 4 times as much. VR displays have 5 pixels/cm
Anti aliasing
Temporal Aliasing Human Flicker fusion 50 Hz Temporal aliasing occurs with moving targets Must compute motion blur to fix the problem
Acuity Distribution
Brain Pixels
Brain pixels=retinal ganglion cell receptive fields Tartufieri Field size = 0.006(e+1.0) - Anderson Characters = 0.046e - Anstis Ganglion cells
Brain pixel distribution Ideally get information into every brain pixel
Pixels and Brain Pixels 0.2 BP 1 bp Small Screen 0.8 BP Big Screen
1280x1024 simulated Monitor CAVE A conventional monitor covers <45% of our brain pixels
Percent of Brain Pixels Uniquely Stimulated in region covered by the display Monitor Cave
How efficiently can we use each display? It will take approximately 2.5x as long to fixate targets at the edge of the big screen Head movements accompany eye movements > 25 deg.
Scale matters Parafovea
Ultimate Display
University of Illinois 100mpixel display
Data walls (near immersion) Stereo, no head tracking, wide screen
CAVE Head tracking – stereo-one user Light scattering problems Interaction problems
Depth of Field 1/3 diopter detectable focus: standard pupil 50 cm43cm60cm 1 m75cm1.5m 2m1.2m6.0m 3m1.5minfinity = + f 1 f 2 f 3
Ultimate Display
Augmented Reality
Issues Depth of focus Occlusion Registration
Augmented reality (Feiner) Add text+images to real world See through glasses Very sensitive to head tracking
Augmented Reality Binoculars Uses a video camera Or Beam splitter.
Why don’t we use HUDs more? Text Television
Why don’t we use HUDs more? Text Television Monocular binocular Screen width Blocking the real world Eyeglasses
Immersadesk Stereo, Head tracking*
Ultra Hi-Resolution Wheatstone Stereoscope