motion capture
DESCRIPTION
These slides accompany a student presentation on Motion Capture for a class in Performance in Film and Videogames at University of Calgary.TRANSCRIPT
Welcome to the
Wonderful World of
Animation!!
Sophia, Michael, Dorothy,
Kevin
Wha
t is
mot
ion
Cap
ture
Animate characters on
computer is relatively
recent Recording movements
of human body for immediate analysis
Roto
scopin
g
An animation technique in which animators trace over footage, frame by frame for use in live-action and animated films1. Capturing video of real actor around props that resemble elements of a scene2. Animators then trace over each frame of the recorded video- result in a figure that moved in a very realistic fashion3. Animated figure would be colored and then integrated with various background layers to create the final shot
Max Fletischer: 1915 Automated production of cartoon films Walt Disney- 1937: Used to create the motion of snow white Snow white and prince= partially rotoscoped
Moti
on C
aptu
re-
com
pute
r gra
phic
s used late 1970 early 1980- in
SFU, MIT, NYIT Robert Abel and Associated
for the National Canned Food
Information Council produced
Brilliance Created human movements:
Black dots on joints + pictures
+creative deductive reasoning
Once able to digitize the results
brought in female model,
painted black dots on 18 joints
photographed her doing
different movementshttps://www.youtube.com/watch?v
=hl2lhtBIt2E&feature=kp
Paci
fic
Data
Im
ages
(PD
I)
American computer animation production
company Bought by DreamWorks
Used different types of
tracking devices that fit
particular projects Wanted to matter in
everything not just specialize in one thing
Goal= entertainment by
3D animation
Wald
o e
ffect
First commercially successful example of a digitally animated figure being performed and rendered in real time - Jim Henson and PDI for Muppet television [Jim Henson Hour] Created a computer generated version of Kermit the Frog
DeG
raf/
Wahrm
an
First live performance of a
digital character a sophisticated talking head
driven by a specially built
controller that allowed a
single puppeteer to control
many parameters of the
character's face, including
mouth, eyes, expression,
and head position. Mike the Talking Head-
1988 Able to interact with the
audience
Kle
iser
– W
alc
zak
Const
ruct
ion
Com
pany Used Keyframe animation: a
drawing that defines the starting
and ending of any smooth
transition Gave the look of flexibility needed
Used in Universal Studios- island of
adventure in Orlando Florida for
The Amazing Adventures of
Spiderman 1987 built and animated computer
generated actors called
“sythespians”: the aim of creating
“life-like figures” based on the
“digital animation of clay models”
https://www.youtube.com/watch?v=
03QMXF2E0Uc Basketball figures for a commercial –
animated trophies and pictures
Hom
er
and
Ass
oci
ate
s:
Motion capture was used to
collect data from an object or
a puppeteered character,
instead of from the actual
performers body Used Elite Motion Analyzer: a
Bio-engeering technology
system Used primarily in Italy for
medical and Industrial
applications This added custom software
geared towards computer
animation to the already
existing configuration
Opti
cal M
oti
on
Captu
re S
yste
m
Components of the Optical
Motion Capture Systems:
CCD (Charged Coupled Device) Camera
Reflective Markers2D component3D component Animation Process
CC
D C
am
era
Optical Motion Capture Systems uses 8 to 32 CCD
Cameras
Each Cameras consists of 124 X 124 light sensitive
Pixels to Millions
More pixels = better the resolution = better the
results.
However greater the resolution lower the frames
per second being captured.
Average is 60 frames per second, up to 120 frames
per second
More frames per second allows you to capture
faster motions.
Camera are often red which is less distracting to the
actors
Cameras works together with Shutter
Synchronization
Reflective
Marke
rs These are placed
usually on the joints
of the body
The reflective
markers can range
from a few
millimeter to a
couple of inches in
size.
Reflective Markers
are bright white/
covered with Scotch-
Brite Tape
The markers should
be brighter than any
other objects on
stage, making it
easier for the
cameras to track
them.
2D
, 3D
Com
ponent
& A
nim
ati
on P
roce
ss
The images captured are transferred to a computerMarkers are located to create a 2D outline of the actorCombining multiple camera angle a 3D model of the actor is created by the intersecting camera rays Lastly the models are transferred into
another software for the animation process
Optical Motion Capture System
Adva
nta
ges
&
Dis
adva
nta
ges
Extremely accurate Large number of markers can be
tracked Not constrained by cables
Larger performance area
Higher sample rate of capture per
second
Expensive Extensive post processing
Controlled environment is needed,
beware of reflective noise
Advantages
Disadvantages
RA
DIO
FR
EQ
UEN
CY
PO
SIT
ION
ING
SYSTEM
Radio frequency > new emerging technology in position
tracking Uses radio frequency
(RF) to calculate position measurement
GPS(G
lobal
Posi
tionin
g S
yste
m)
GLOBAL POSITIONING SYSTEM
(GPS) most recognized example of Radio
frequency found in vehicles, mobile phones,
computers, wristwatches, dogs , etc.
Developed by US department of
Defense ( 1970s) 1983 > nonmilitary use of GPS
was made available by President
Reagan Made intentionally less accurate by
the government 2000’s > this changed with the
advance in technology b/c no longer distorted signals for
security purposes
GPS(G
lobal
Posi
tionin
g S
yste
m)
HOW IT WORKS? United states > GPS constellation consists of
24 satellites Travels 12 000 miles above earth in precise
orbit Full rotations are made around earth every
12hours Designed so that at least 5 satellites have a
view of any point on the surface of the earth
GPS units receive the signals of the satellites
> compute location to coordinate system
Based on longitude and latitude
*** not accurate enough to use as a
motion capture tool however this is
changing with technology (development
of more localized transmitters > more
accurate readings and frequency display)
LPS (
Loca
l posi
tionin
g S
yste
m)
Systems that use RF
to measure highly accurate positioning
data at a large sample
rate Considered to be the
most viable for motion
capture application >
motion capture standard
LPS (
Loca
l Po
siti
onin
g S
yste
m)
HOW IT WORKS? Most RF position systems (GPS, RTLS) obtain
measurements by calculating the time it
takes for a signal to travel from transmitter to
receiver Speed of signals are too high > makes motion
capture difficult to nearly impossible
Problem > finding a solution to balance out the
signal without jeopardizing the accuracy of the
transmission Technology development slowly resembling
optical systems Similar to GPS but works in an inverse way.
Difference > object captured send signal as
opposed to receiving them
Moving objects fitted with transmitters > send
signals > antennas receive signals > signals sent to
processing unit> calculates the position using the
location of each antennas
Accuracy of location is determined by the distance
between signals in relation to the distance of
antennas What does this mean for gaming ? > LPS
systems could enable a new level of virtual
reality
LPS (
Loca
l Po
siti
onin
g S
yste
m)
ADVANTAGES & DISADVANTAGES (LPS)
(+) LPS systems calculate all
accurate measurements in
real time (+) Works outdoors and
indoors (+)Cheap to manufacture
(+) Can be worn on/ under
clothes (-) Potential for possible RF
interference Standard Frequencies must be
altered
Electromagnetic
Trackers
Components of the Electromagnetic Trackers: Transmitter
11-18 SensorsElectronic Control Unit (Computer)
Software
Electromagnetic Trackers are used in today’s major video gamming companies for wireless controllers such as the Wii
Ele
ctro
magneti
c Tr
ack
ers
Pro
cess
Transmitter sends out a low frequent electromagnetic field
Sensors detects the magnetic field
Sensors send signals to the Electronic Control Unit (Computer)
Using the software, the location of the sensors are found and is used to create a model
Model is used to create an animation
Adva
nta
ge a
nd
Dis
adva
nta
ge
Real-time data output
No post-position needed
Less expensive Can capture multiple setups
Sensitivity to other metals
Performers constrained by
cables Lower sample rate Capture area is smaller
Advantages
Disadvantages
ELE
CTR
OM
EC
HA
NIC
AL
PER
FOR
MA
NC
E S
UIT
Systems of structures linked by
potentiometers, gyroscopes, or similar
angular measurement devices located
on major human joint locations.
Newer versions use micro-
electromechnical systems (MEMS)
Inertial sensors placed over lycra or spandex suit.
Idea is that the suit measures all human limb rotations
Smaller and more accurate
Ie. Nintendo Wii input device, Iphones
ELE
CTR
OM
EC
HA
NIC
AL
PER
FOR
MA
NC
E S
UIT
ADVANTAGES AND
DISADVANTAGES (+) large range of capture
(+) less expensive than optical and
magnetic systems (+) portable (+) Real-time data collection is
possible (+) possible to capture multiple
performers simultaneously with
multiple set (-) systems apply constraints on
human joints (-) configuration of sensors is fixed
(-) Most systems do not calculate
global transitions
Dig
ital
Arm
atu
res Key-frame and Stop
motion armatures
Posing device manually to
generate keyframes in software
Real-Time / Puppeteering Armatures Real-time, using a puppeteer
2 Types:
Din
osa
ur
Input
Devi
ce
Jura
ssic
Park
Faci
al M
oti
on
Captu
re S
yste
ms
Real Time Optical Face
Trackers Camera placed in a structure so
it moves with the performer
Captures motions of small markers
placed on different areas of the face
http://www.youtube.com/watch?v=
gYP2tInr_YY
The B
est
Form
of
Faci
al M
oti
on
Captu
re S
yste
ms
A combination of optical capture and software algorithms Muscle skin simulators
Dynamic Blend Shape
Solvers Photogrammetry Builders
Faci
al M
usc
le
and S
kin
Sim
ula
tors Algorithms that take
optical data of the face and use it to solve facial poses based on anatomical
rules and restrictions.
Dyn
am
ic B
lend
Shapes
http://www.bokwon.net/img/3d/rigexprsheet.jpg
Most Popular Method* Building a series of models of the
characters face* Algorithms put them into a stream of
shapes
Oth
er
Moti
on
Captu
re S
yste
ms
The Waldo Telemetric device that
imitates the motion of
whatever it is controlling Transmits measurements
of motion to a mimicking
device HandtrackersData Glove – captures
motion if small body parts
Dis
cuss
ion?
1) What devices today
use radio frequency?
2) Referring back to the
“Sweetie” video that
was just seen in class,
are there any negative
aspects associated with
this growing technology? 3) Where do you think
motion capture will be
in the near future?