Choosing an NDI Optical Tracking Technology
The type of tool you need for your application may help you determine which Polaris® system you need to use.
A passive system (Polaris Vicra®, passive Polaris Spectra®) tracks passive and active wireless tools only. A hybrid system (hybrid Polaris Spectra®) tracks active, passive and active wireleless tools.
NDI's technical specialists can work with you to help determine the best technology for your application while considering the following differences.
|
Passive System
|
Hybrid System
|
- Passive tools use spherical, retro-reflective markers that reflect infrared light emitted by the illuminators on the Position Sensor
- No physical connection of the tool to the system
- Can track numerous tools at the same time without reducing the sampling rate
- Offers simple tool construction
- Requires each tool to have a unique marker geometry which means larger tool sizes with each geometry
- Passive spheres need to be replaced after use
- Difficult to clean passive spheres intra-operatively
- Is less expensive than the hybrid system
|
- Active tools incorporate infrared-emitting markers that are activated by an electrical current
- Tools are connected to the SCU via a cable
- Tool marker geometries can be small since the same geometry can be used multiple times
- Markers can be cleaned easily
- Can incorporate switches and visible LEDs
- Tool Definition File can be programmed into tool
- Markers have limited life and are not replaceable
- Sampling rate is reduced with every third active tool added
- More complex to build than passive tools
- SCU has GPIO port that can be used for devices such as a foot switch for feedback to the application
- SCU has multiple connectivity options (i.e. RS-232, USB)
- SCU has synchronization port
|
