Motion Capture in Motion Capture in 3D Animation3D Animation

Edward TseEdward Tse

Motion Capture as a Motion Capture as a ToolTool Motion capture (MOCAP) is an Motion capture (MOCAP) is an

effective 3D animation tool for effective 3D animation tool for realistically capturing human realistically capturing human motion motion

OutlineOutline

RotoscopingRotoscoping The MOCAP PipelineThe MOCAP Pipeline Limitations of MOCAPLimitations of MOCAP The Future of MOCAPThe Future of MOCAP

By the Power of

Appendix B!!

RotoscopingRotoscoping

Captured VideoCaptured Video

HistoryHistory

Johnston, et al., 1995Johnston, et al., 1995

RotoscopingRotoscopingHistoryHistory

TracingTracing

Johnston, et al., 1995Johnston, et al., 1995

RotoscopingRotoscoping

Post ProcessingPost Processing

Johnston, et al., 1995Johnston, et al., 1995

The MOCAP PipelineThe MOCAP Pipeline

CalibrationCalibration CaptureCapture 3D Position Reconstruction3D Position Reconstruction Fitting to the SkeletonFitting to the Skeleton Post ProcessingPost Processing

CaptureCapture

Optical Magnetic Mechanical

Costa-Sousa, M., 2004Costa-Sousa, M., 2004

Infra Red LEDsInfra Red LEDs

Magnetic Transmitter

PotentiometersPotentiometers

CalibrationCalibration

Image Image SpaceSpace

World World SpaceSpace

(X,Y)(X,Y) (X,Y,Z)(X,Y,Z)

(X,Y)(X,Y) (X,Y,Z)(X,Y,Z)

(X,Y)(X,Y) (X,Y,Z)(X,Y,Z)

3D Position 3D Position Reconstruction Reconstruction (Utopia)(Utopia)

PCIkC

PCIkC

2222

1111 CIkCCIkC 22221111

CIkCCIkC

CIkCCIkCCIkCCIkC

zzzzzz

yyyyyy

xxxxxx

22221111

22221111

22221111

3D Position 3D Position Reconstruction Reconstruction (Reality)(Reality)

Multiple MarkersMultiple Markers

For small number of markers: SizeFor small number of markers: Size Occlusions are a problemOcclusions are a problem Multiple Hypothesis TrackingMultiple Hypothesis Tracking

Ringer, et al., 2002

C1

C2

Multiple MarkersMultiple Markers

Mechanical Optical HybridsMechanical Optical Hybrids

http://www.animazoo.com/services/gypsyHybrid.htmhttp://www.animazoo.com/services/gypsyHybrid.htm

Fitting to the SkeletonFitting to the Skeleton

Utopian approachUtopian approach– 10 – 20% length 10 – 20% length

changeschanges Markers on both Markers on both

sidessides Joint Joint

DisplacementDisplacement Use Rotation Use Rotation

Angles OnlyAngles Only

Post ProcessingPost Processing

Motion EditingMotion Editing– Cut, Copy, PasteCut, Copy, Paste

Motion WarpingMotion Warping– Speed up or Slow DownSpeed up or Slow Down– Rotate, Scale or TranslateRotate, Scale or Translate

Motion Signal ProcessingMotion Signal Processing– Smoother MotionsSmoother Motions

Limitations of MOCAPLimitations of MOCAP

Subject to data inaccuracySubject to data inaccuracy ExpensiveExpensive

DeviceDevice Cost for Body Cost for Body capture (USD)capture (USD)

MechanicalMechanical $20’000 – $30’000$20’000 – $30’000

ElectromagnetiElectromagneticc

$100’000 – $100’000 – $120’000$120’000

OpticalOptical $90’000 – $210’000$90’000 – $210’000

Limitations of MOCAPLimitations of MOCAP

Only realistic motion capturedOnly realistic motion captured– Cartoony Animations not possibleCartoony Animations not possible

WYSIWYG (what you see is what you get)WYSIWYG (what you see is what you get)– Can’t add more expressionCan’t add more expression– Continally need to recapture motionContinally need to recapture motion

Robertson, B., 2001

The Future of MOCAPThe Future of MOCAP

Markerless MOCAPMarkerless MOCAP Cheaper MOCAPCheaper MOCAP MOCAP as Input to Large DisplaysMOCAP as Input to Large Displays

hollywoodjesus.com

Ngan, S., 2004Bregler et al., 2002

ConclusionConclusion

Motion capture (MOCAP) is an Motion capture (MOCAP) is an effective 3D animation tool for effective 3D animation tool for realistically capturing human realistically capturing human motion motion

Questions?

ReferencesReferences

Johnston, O., Thomas, F., (1995) The Illusion of Life: Disney Johnston, O., Thomas, F., (1995) The Illusion of Life: Disney Animation, Disney Editions, ISBN: Animation, Disney Editions, ISBN: 0786860707 0786860707

Costa-Sousa, M. (2004) Motion Synthesis, Powerpoint Costa-Sousa, M. (2004) Motion Synthesis, Powerpoint PresentationPresentation

Parent, R. (2002) Computer Animation: Algorithms and Parent, R. (2002) Computer Animation: Algorithms and Techniques, Morgan Kaufmann PublishingTechniques, Morgan Kaufmann Publishing

Ringer, M., Lasenby, J. (2002) Multiple Hypothesis Tracking Ringer, M., Lasenby, J. (2002) Multiple Hypothesis Tracking for Automatic Optical Motion Capture, European Conference for Automatic Optical Motion Capture, European Conference on Computer Vision (ECCV ’02)on Computer Vision (ECCV ’02)

Robertson, B. (2001) Medieval Magic, Computer Graphics Robertson, B. (2001) Medieval Magic, Computer Graphics World, April 2001. World, April 2001.

Tse, E. (2004) The Single Display Groupware Toolkit, MSc Tse, E. (2004) The Single Display Groupware Toolkit, MSc Thesis, University of Calgary, Ab, CanadaThesis, University of Calgary, Ab, Canada

Bregler, C., Loeb, L., Chuang, E., Deshpande, H., (2002) Bregler, C., Loeb, L., Chuang, E., Deshpande, H., (2002) Turning to the Masters: Motion Capturing Cartoons, Turning to the Masters: Motion Capturing Cartoons, Proceedings of ACM Siggraph 2002 pp 399 – 407.Proceedings of ACM Siggraph 2002 pp 399 – 407.

vicon.com, inition.co.uk, polhemus.com, wikipedia.org, vicon.com, inition.co.uk, polhemus.com, wikipedia.org, animazoo.com, animazoo.com, hollywoodjesus.comhollywoodjesus.com

Bonus SlidesBonus Slides

Stuff that’s too cool for you!Stuff that’s too cool for you!

StatsStatsInput Device Frame Rate

Range (hz)

Position Accuracy

Orientation Accuracy

Latency & range

Maximum Points tracked

Use in Movies Cost Range (USD)

Polhemus (Magnetic)

60-240 .03in RMS static0.00015in at 12in range

.15° RMS static

0.0012° at 12in range

3.5ms5 ft

16 Woody and Hamm in Toy Story, The Chandelier in Beauty and the Beast

$8’495 - $21’925

Vicon (Optical)

166-10’000 1/117’600in or 0.02 of a Pixelup to 4MP

No camera limit

500 Sony, Nintendo, Microsoft, Boeing,

$89’170 - $209’920

Ascension ReActor 2 (Magnetic)

100 0.08cm RMS at 1.52m range

0.5° RMS at 1.52m range

4.11m x 4.11m area

30 $99,410 - $102’315

Gypsy (Mechanical) wireless possible

12-120 No Absolute position

1° 200m 42 $20’000 - $27’000

θ1

θ2

CalibrationCalibration

OutlineOutline

History History Motion Capture PipelineMotion Capture Pipeline LimitationsLimitations Future WorkFuture Work