Realtime 3D Computer Graphics Virtual Reality

juicebottleAI and Robotics

Nov 14, 2013 (3 years and 6 months ago)

89 views

Realtime 3D Computer Graphics
V
irtual Reality
Marc Erich Latoschik
AI & VR Lab
Artificial Intelligence Group
University of Bielefeld
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
V
irtual Reality (or VR for short)…
…can be defined as …

…an
artificial environment
which is experienced through
sensory stimuli
(as
sights and sounds) provided by a computer and in which
one's actions
partially
determine what happens in the environment (Merriam W
ebster)

…a
human-computer interface
which -by addressing several
senses-
lets us
perceive
a computer generated environment as reality
. (based on
Alexander
Hennig "Die andere Wirklichkeit (the other reality)“)

…the
simulation
of a real or imagined environment that can be experienced
visually
in the three dimensions of width, height, and depth
and that may
additionally provide an
interactive experience
visually in full
real-time
motion
with sound and possibly with tactile and other forms of feedback.

…(and many more)
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
The term(s) of V
irtual Reality

Phantomology or phantomatic


is introduced by Stanislav Lem as a concept of
artificial realities in his Summa
T
echnologiae (Lem,
1964) and in several publications since then.

V
irtual Reality


This term is attributed to Jaron Lanier of VPL

in 1986 in a conversation regarding the work
of Scott Fisher
.


V
irtual Environments


is how Fisher
, of NASA

Ames, had been
referring to the field.

Artificial Reality


is a label for such activities by
Myron Krueger in 1983.


Cyberspace


This term is coined by William Gibson in his book
Neuromancer (Gibson, 1984).
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR
Flavors

Artificial Reality
User is observer of an artificial environment, uses an avatar as a
placeholder for the user
.

Augmented Reality
Merges reality with V
irtual Reality
. Naturally and artificially generated
stimulus is overlapped and complements each other
.

Cyberspace
Emphasizes the network related parts of and artificial computer
generated environment.

Immersive V
irtual Reality
Embeds the user psycho-physically into the artificial surrounding.
User merges into the generated environment.

Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR characteristics
1
1.
immersion:

T
o submerge into simulated space.
2.
multidimensionality:
Used to create space.
3.
real-time:
Simulation is processed in real-time.
4.
adequacy:
Movement results in an appropriate simulation change.
5.
interaction:
Users can interact with the environment.
6.
navigation:
Movement in the simulated space
(as would be possible in reality).
7.
reality-effect:

T
o perceive the artificial surrounding as real and
believable.
8.
multi-user:
Multiple users can enter the virtual space and
communicate and interact.


1
following (Bühl, 1997)
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR - simulating stimuli
Phantomology
peripheral
external
sensation source
central
direct
brain excitation
Sense:
a system that consists of a
sensory cell type (or group of cell types)
that respond to a specific kind of physical
energy
, and that correspond to a defined
region (or group of regions) within the
brain where the signals are received and
interpreted (Wikipedia)


VR is simulation of stimuli for human senses.

No agreement about the number of actual senses (at least 9).

The better the simulation the higher is the degree of immersion.

W
...r
esidual self image
...
...mental pr
ojection of digital self...
...what is r
eal?
...electrical signals interpr
eted b
y y
our brain...
...see
...
...taste
...
...smell...
..f
eel..
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR - simulating stimuli
reality
virtuality
hearing
sight
touch
taste
smell
Simulating stimuli:

VR simulates stimuli to 5 main senses (following
Aristotle)

Senses are gradually simulated to bridge reality and virtuality
.


The dif
ferent VR-flavors stimulate

dif
ferent senses to

dif
ferent degrees.
central

phantomology
peripheral phantomology
Immersive V
irtual Reality
Non-immersive
V
irtual Reality
Pre-virtual worlds
CMC, mediazation
deg. of immersion
sight
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR and the notion of space

Simulating sensual stimuli is done by setting certain
parameters (to generate stimuli).

Every parameter defines a one dimensional range of
possible values.

Combining several parameters for the same stimulated
sense creates a “sense space” For example:

R,G,B (or HIS, HSV etc.) parameters open a color space.

Sweet, sour
, salty
, bitter
, umami parameters open a gustatory
(taste) space.

Pitch, volume and duration open a sound space.

X,
Y
, Z (or length, height and width) open an 3D (possibly
Euclidian) space.
1
following (Bühl, 1997)
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
VR and the notion of space

Perceptual (mental) Space

Important aspect in philosophy and cognitive science.

Things appear extended because they have the attributes
of color and solidity (David Hume).

has a projective geometry
, things within it appear as if they are
viewed from a point (Rene Descarte).

Projective geometry might describe the layout of things in
perception (Peters, 2000).
1
following (Bühl, 1997)
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
Simulation of sensory stimuli

VR is about the simulation of sensory stimuli which fake stimuli sensed in the
real physical world.

The human sensory systems consists of several sub-systems all with their
own features and modes of operation, e.g.

sensed space(s)

processing speed

processing resolution

processing accuracy

Stimulation of a certain sensory system requires to take that system’
s mode of

operation into account.

For example:

The simulation of tactile feedback (haptics) requires a much higher simulation rate
as the simulation of visual stimuli.

The resolution of the auditory sense is dif
ferent then the resolution of the visual
sense.
!
Creating
visual
stimuli is considered critical for immersive VR.
This is followed

by
tactile
and
auditory
and then by
olfactory
and
gustatory
simulation.
Realtime 3D Computer Graphics / V
irtual Reality – WS 2005/2006 – Marc Erich Latoschik
Space: creating visual stimuli

V
isual stimuli are a major source for the perception of space.

Simulating the surrounding virtual space of users is the goal.

VR utilizes real-time 3D computer graphics (CG) to create visual stimuli.
Conventional 3D CG in contrast to VR:
3D Computer Graphics
V
irtual Reality
Purely visual presentation
Multimedia presentation
visual, acoustic, haptic,…
Presentation can be rendered
of
f-line, time is uncritical
Real-time presentation
Static scenes or predefined
animations
Real-time interaction and
simulation
2D interaction
mouse, keyboard
3D interaction with special input
devices + speech (and gesture)
AI &
VR Lab:

Vir
tual Biospher
e II
AI &
VR Lab:

Vir
tual Biospher
e II