Synthesis and Analysis Techniques for the Human Body: R&D Projects - 3D Modeling and Animation: Synthesis and Analysis Techniques for the Human Body - page 347

Table 1. Comparison of current motion capture systems (IST HUMODAN,
2001).

Systems Advantages Disadvantages

Optical data are extremely accurate in most cases. Optical data requires extensive post-

processing. A larger number of markers can be used.

It is easy to change marker configurations. The hardware is expensive, costing

between $100,000 and $250,000.

It is possible to obtain approximations to internal
skeletons by using groups of markers. Optical

Systems

Optical systems cannot capture
motions when markers are occluded
for a long period of time.

Performers are not constrained by cables.

Optical systems allow for a larger performance
area than most other systems. Capture must be carried out in a

controlled environment, away from
yellow light and reflective noise.

Optical systems have a higher frequency of
capture, resulting in more samples per second.

The tracker's sensitivity to metal can
result in irregular output. Real-time data output can provide immediate

feedback.

Performers are constrained by cables
in most cases. Position and orientation data are available without

post-processing. Magnetic trackers have a lower

sampling rate than some optical
systems.

Magnetic
Trackers

Less expensive than optical systems, costing
between $5,000 and $150,000.

The sensors are never occluded. The capture area is smaller than is

possible with optical systems. It is possible to capture multiple performers

interacting simultaneously with multiple set-ups. It is difficult to change marker

configurations.

The range of capture can be very large. Low sampling rate.

Electromechanical suits are less expensive than
optical and magnetic systems.

They are obtrusive due to the amount
of hardware.

Electro-
mechanic
al Body
Suits

The suit is portable. The systems apply constraints on

human joints. Real-time data collection is possible.

Data is inexpensive to capture. Configuration of sensors is fixed.

The sensors are never occluded. Most systems do not calculate global

translations without a magnetic
sensor.

It is possible to capture multiple performers
simultaneously.

recognition of human motion and its reconstruction and analysis for different
applications. Nevertheless, the current limitations of these tools limit the range
of application of this technology to off-line analysis.
The principal technologies used today are optical, electromagnetic, and electro-
mechanical human tracking systems. Table 1 summarizes the advantages and
disadvantages of the different human tracking systems.