Global Positioning System Reference
In-Depth Information
7.4.5
Motion Capture
Very accurate camera-based 3D positioning is used in motion capture systems
employed by animators in video content production. For example, realistic human
motion from a real actor is captured so that the motion may be modeled for use
with an entirely artificially generated computer-based character (modeled in 3D
graphics software). The character Gollum in the
Lord of the Rings
trilogy was
created in this way. As well as body motion it is common to capture detailed facial
movement in order to generate realistic lip movement for dubbed voiceover.
Various techniques are used including the positioning of passive reflective
dots at key motion points and active LED beacons. These techniques are very
tightly bounded and careful camera positioning and calibration are essential.
Large arrays of cameras may be used, and it is still an expensive and highly
professional activity. It may however, become possible to offer consumer variants
especially as home computing capabilities (especially multicell graphics
processors) improve. A future games machine could include motion capture
positioning perhaps from several small cameras to cover a wide area to enable
gamers (or artists) to interact and act along with screen-based, computer-generated
characters. This is one of the ways in which the real world and its mapping will
become enhanced with overlays from virtual worlds leading to augmented reality
(see Section 5.5).
Figure 7.3
Motion capture positioning using a bank of optical cameras.
