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Lecture 19:Lecture 19:Motion CaptureMotion Capture

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TechniquesTechniques

MorphingMotion Capture

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MorphingMorphing

Morphing is merging between imagesMorphs can turn any form into

another.Usually done by copying the original

object (source image) and transform it vertex by vertex into the target image

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MorphingMorphing

Metamorphosis of shape and color from a source image to a target image

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MorphingMorphing

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Motion CaptureMotion Capture

Keyframing complex action (walking, etc) requires a lot of key frames

Instead, capture motion from real objects. Creatures and/or actors performing the desired motion

The positions of key points on the actor are tracked. This motions are mapped to corresponding points in the model

May be necessary to generate secondary actions for the computer model (tracking is expensive)

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Tracking Technology - Tracking Technology - electromagneticelectromagneticTracking technology include:

Electromagnetic position and orientation sensors

- requires a wire to each sensor- Readings can be distorted by metal and

magnetic fields- Limited working volume

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Tracking Technology - Tracking Technology - electromagneticelectromagnetic Component :-

– Transmitter : gives off an magnetic field– Sensor : oftened attached to HMD or gloves– Interface device : filter/wire to pass information– Computer

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Tracking Technology - Tracking Technology - electromagneticelectromagnetic

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Tracking Technology - Tracking Technology - electromagneticelectromagnetic

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Tracking Technology - opticalTracking Technology - optical

Tracking technology include:Optical triangulation

- reflective or emissive markers are attached to objects

- two cameras triangulate position

- can track more points cheaply, without wires

- points can be occluded

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Tracking Technology - opticalTracking Technology - optical Body to be tracked is equipped with markers that

are often covered with retroreflective surfaces. Tracking camera recognize these markers Data handed over to CPU for processing Result = coordinates of the markers + position of

the tracked body

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Motion Capture Motion Capture (Optical capture)(Optical capture)

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Motion Capture Motion Capture (Optical capture)(Optical capture)

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Motion CaptureMotion Capture

Tracking technology include:Datagloves

Track the hand and fingers

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DataglovesDatagloves

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Motion CaptureMotion Capture

Tracking technology include:Body suit

Fibers in instrumented clothing detect angles of all joints

PuppetryReal-time data collected from an arbitrary

input deviceMapped to an computer model, which is

displayed in real time during capture

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Motion CaptureMotion Capture

http://www.animocap.com/skit/tutart/tutorials/ha03_yourFirstPerformance.html

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Problems with Motion CaptureProblems with Motion Capture

Motion capture tends to require more-or-less exotic technology

Even puppetry requires at least real-time graphics

Problems with motion capture includesHow do we map motion paths to objects of a

different shape and scale?How do we deal with noise and missing dataHow can we reduce the number of samples

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Application Example:Application Example:

http://www.lordoftherings.net/legend/video/

http://locomotionstudios.com/gallery1.html#