Perceptual versus Cultural

a

AB

C

D

Architecture for visual thinking

a

AB

C

D

Intro to Human Visual System and Displays

Fundamental Optics Fovea The ultimate Display

Human Visual Field

aa

100

80

60

LEFT RIGHT

40

20

Visual Angle

dr

h

1 diopter: a lens that focuses at 1 meter.

45d

~15d

Acuities

Vernier super acuity (10 sec)

Grating acuityTwo 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

Input pattern

Output pattern

Pixel matrix

Temporal Aliasing

Human Flicker fusion 50 Hz Temporal aliasing occurs with moving

targets Must compute motion blur to fix the

problem

Acuity Distribution

aaa

10 30 50103050

Distance from Fovea (deg.)

100

80

60

40

20

Brain Pixels

Brain pixels=retinal ganglion cell receptive fields

Tartufieri

Field size = 0.006(e+1.0) - AndersonCharacters = 0.046e - Anstis

Ganglion cells

Brain pixel distribution

Ideally get information into every brain pixel

aaa

10 30 50103050

Distance from Fovea (deg.)

100

80

60

40

20

Pixels and Brain Pixels

aaa

10 30 50103050

Distance from Fovea (deg.)

100

80

60

40

20

0.2 BP

1 bp

Small Screen

0.8 BP

Big Screen

1280x1024 simulated

Monitor

0

100

200

300

400

500

600

700

0 50 100 150 200

Display Width (cm)

Bra

in P

ixel

s

Total BP

BP Stimulated

CAVE

A conventional monitor covers <45% of our brain pixels

Percent of Brain Pixels Uniquely Stimulated in region covered by the display

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200

Display Width (cm)

Per

cen

t st

imu

late

d

Display

Parafovea

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

a

High resolutionbinocular insert (25x19)

Left eyebackground(82.5x66.7)

Right eyebackground(82.5x66.7)

Binocular overlap

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 cm 43cm 60cm 1 m 75cm 1.5m 2m 1.2m 6.0m 3m 1.5m infinity

1 1 1 = +

f1 f2 f3

Ultimate Display

Use an eye tracker tomeasure direction of gaze

Ascertain distance toobject

Change focal length oflens so that fixated virtualobject is at correct focal distance

Screen

Compute graphics imagery so thatobjects at different focal distancesappear out of focusAttempt to determine

fixated object

Ultimate Display

Augmented Reality

Virtual imagery

Real-world imagery

Computer Display

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