Motion Capture Technology

by

T.Aswanth

Id no-12006270

No-49(sec-D)

What is Motion Capture?

Motion capture (mocap) is sampling and recording motion of humans, animals and inanimate objects as 3d data for analysis, playback and remapping.

Motion Capture of an object involves sensing,digitizing, and recording that object in motion

• Whole body

• Hands ,Limbs

• Face

• One way of acting out an animation

History of Motion Capture

• Eadweard Maybridge (1830-1904)• Etienne-Jules Marey (1830-1904)• Harold Edgerton (1903-1990)

Marey and Maybridge conducted human and animal motion studies by shooting multiple photographs of moving subjects over a short period of time.

Harold Edgerton was the inventor of flash photography.

Motion Capture Technologies:

There are primarily five methods in motion capture. They are :

Prosthetic (or Electromechanical)AcousticElectromagneticOptical fiberOptical

Prosthetic(or Electromechanical) Motion Capture:

Prosthetic Motion Capture uses Potentiometers on the plastic exoskeleton that an actor must “wear”, and then act out their movements. This is very accurate and transmits real-time data at a far greater range than any other technology.

Acoustic Motion Capture:

Acoustic Motion Capture uses audio transmitters on the actor’s body and Set of microphones receive sound waves.

Other sounds in frequency range can disrupt capture

Accuracy not as high as other systems

Limited Rage and Limited number of sensors

Electromagnetic Motion Capture:

This approach has a central magnet with several receivers attached to the actor’s body. The receivers capture and record the actors movements and save them to the computer.

This motion capture method can be hindered by

nearby metal objects if they are large

enough and depending on the power of

magnets being used.

Optical Fiber Motion Capture:

Fiber-optic sensor Bend and twist sensors measure transmitted light No occlusion Multiple subjects Portable Adjustment to individual proportions is limited Less accurate data

Optical Motion Capture:

Reflective markers High speed capture High data accuracy Multiple Cameras that digitize

different views of performance

Production Process:

Sensor Calibration

Subject Calibration

Record Movements

Marker Data Cleanup

Convert to Joint Angles

Mapping to characters

Post Processing:

Motion Editing: Cut, Copy, Paste

Motion Warping: Speed up or Slow Down Rotate, Scale or Translate

Motion Signal Processing: Smoother Motions

Limitations of MOCAP

o Subject to data inaccuracyo Expensiveo Only realistic motion capturedo Cartoony Animations not possibleo WYSIWYG (what you see is what you get)o Can’t add more expressiono Continally need to recapture motion

The Future of MOCAP

Markerless MOCAP Cheaper MOCAP MOCAP as Input to Large

Displays

Input 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 static0.0012° 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

Stats:

Feature Films:

• Avatar • Curious Case of BenjaminButton• Pirates of the Carribean• The Incredible Hulk• Lord of the Rings• Polar Express• Matrix• Kocchadaiyan• Dawn of the planet of the apes

Conclusion:

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

Any Questions ?????

Thank you!!!!