
3 Markers and targets (rigid bodies)
3.1 Passive markers
Passive markers used in
ART
tracking systems are retro-reflective, which means they
reflect a high fraction of the incoming light in a small cone around the incoming light’s
direction (cat’s eye effect). More precise: the IR radiation is reflected into a narrow range
of angles around the (opposite) direction of the incoming light. Passive markers can be
either
1. spherical markers:
+ excellent visibility from any perspective,
- expensive fabrication,
- sensitive surface,
- target requires larger volume
→
danger of mechanical damage.
2. flat markers:
+ low price,
+ flat targets possible,
+ robust surface because cover may be applied,
- the angular range of visibility is limited to approx.
±
45
◦
.
3. ring markers:
+ low price,
+ cylindrically shaped targets possible,
+ robust surface,
- the angular range of visibility is limited to approx.
±
45
◦
.
Passive markers are mostly spheres covered with retro reflecting foils. However, they can
also be stickers made from retro reflecting material.
Retro reflecting sheets or foils available on the market can be based on two different op-
tical principles:
20
Содержание Flystick3
Страница 220: ...10 General Information 10 4 Declaration of conformity 220 ...
Страница 221: ...10 4 Declaration of conformity 221 ...
Страница 222: ...10 General Information 222 ...
Страница 223: ...10 4 Declaration of conformity 223 ...
Страница 224: ...10 General Information 224 ...
Страница 233: ...10 4 Declaration of conformity 233 ...
Страница 234: ...10 General Information 234 ...
Страница 235: ...Appendix 10 4 Declaration of conformity 235 ...
Страница 248: ...A Technical specifications ARTTRACK2 discontinued ARTTRACK3 discontinued TRACKPACK discontinued 248 ...
Страница 249: ...Appendix A A 7 System latency TRACKPACK Cascade discontinued 249 ...
Страница 269: ...Appendix B B 3 Input of Special Control Data via Ethernet tfb 2 0 0 1 0 0 5 0 1 0 8 0 5 269 ...