Glossary
Motion Capture
The recording of human and animal movement by any means. Today's
modern motion capture is mainly recorded by either video, magnetic,
or electro-mechanical devices.
Performance Capture
The recording of a performance, either human or animal, using a
MOTION CAPTURE system (or similar
technology) - difference being that you can motion capture a table,
but it is cannot give a performance.
MoCap
MoCap = MOtion CAPture
Magnetic Motion Capture Systems
A magnetic field generator is set up in the room. MAGNETIC
SENSORs are placed on the subject's body that each detect their
individual position and orientation relative to the generator
Magnetic Sensor
Magnetic sensors are used in MAGNETIC systems.
These are equivolent to a MARKER, but also
able to detect orientation as well as position.
Marker
Markers are used in OPTICAL systems. They
are either reflective "balls" in a PASSIVE
system, or LEDs in an ACTIVE system, worn
by the subject. It is the position of these markers that is recorded
during motion capture.
Optical Motion Capture Systems
There are 2 types of optical motion capture systems:
Passive
An array of video cameras surround the subject to be recorded.
Each camera has a ring of lights (LED's - Light Emitting Diodes)
around the lens that send light towards the subject. This light
bounces back off refective MARKERs that
have been placed on the subject.
Each camera sees a different picture of the MARKERs
since each camera is in a different position in the room. These
pictures are used to work out the reletive poisition of each camera,
and hence the real world 3D position of the MARKERs.
Active
Similary to PASSIVE, but instead of the
camera LEDs sending light to bounce off the MARKERs,
the MARKERs themselves are the LEDs and
send light to sensors (cameras) in the room.
|