1 Lecture 19: Motion Capture

2 Techniques Morphing Motion Capture

3 Morphing Morphing is merging between images Morphs 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

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

5 Morphing

6 Motion 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)

7 Tracking Technology - electromagnetic Tracking 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

8 Tracking Technology - electromagnetic Component :- –Transmitter : gives off an magnetic field –Sensor : oftened attached to HMD or gloves –Interface device : filter/wire to pass information –Computer

9 Tracking Technology - electromagnetic

10 Tracking Technology - electromagnetic

11 Tracking 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

12 Tracking 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

13 Motion Capture (Optical capture)

14 Motion Capture (Optical capture)

15 Motion Capture Tracking technology include: Datagloves Track the hand and fingers

16 Datagloves

17 Motion Capture Tracking technology include: Body suit Fibers in instrumented clothing detect angles of all joints Puppetry Real-time data collected from an arbitrary input device Mapped to an computer model, which is displayed in real time during capture

18 Motion Capture e.html

19 Problems 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 includes How do we map motion paths to objects of a different shape and scale? How do we deal with noise and missing data How can we reduce the number of samples

20 Application Example: