Optical Measurement Systems

Optical 3D measurement systems in the close-range infrared field deliver reliable position data. Suitable for use in many areas, our Polaris and Optotrak optical measurement systems have been popular with our customers for years – whether for medical or industrial fields of application. They are developed and produced at our parent company in Canada.

Our optical systems are highly accurate and used in particular for surgery with rigid instruments. Reflective markers are affixed to the instruments. The markers are detected by a camera, and the instrument’s position is shown on a medical image. This enables the surgeon to navigate the instrument in real time and to reach the required location. Due mainly to its easy integration, this measurement system has been established on the market for years and is used by many medical technology companies.

Principle of Operation

  • Optical markers are affixed to rigid objects (3 markers for spatial position determination)
  • The cameras of the 3D measurement system specify a measurement range and capture the marker positions within this range
  • The system transmits the position and orientation data to the application software, which processes it according to the application requirement, e.g. for visualization


  • Real-time 3D measurement (position and orientation)
  • High accuracy of the optical measurement systems
  • Larger measurement range than EM systems
  • Easy setup in practice
  • No radiation risk from the measurement system because infrared measurement technology does not pose a health risk

Our customer’s fields of application for optical measurement systems


Reaching the tumor safely and quickly: by position determination of neurosurgical tools with reference to pre-operative brain images.


Achieving optimal prosthetic fit: by position determination of orthopedic tools, including robot arm in knee endoprosthetics.

Spine surgery

Positioning spinal implants accurately: by position determination of surgical tools.


Avoiding damage to healthy tissue during radiation: by pre-positioning the patient in a linear accelerator and detecting their motions.


Motion analysis: a large number of measurement points are captured with a high update rate. This is a key requirement in many research projects.


Wind tunnel tests or wing deflection: industry benefits from the exceptional accuracy of optical systems.

Polaris and Optotrak compared

Compare productsPolarisOptotrak
Product image
Max. measurement size3 m³~35 m³
3D volumetric accuracyup to 0.12 mm RMSup to 0.1 mm RMS
Max. number of markers25 tools, up to 6 markers per tool512 individual markers
Max. measurement rate250 Hzapprox. 4600 Hz/(number of markers +1.3)
Product rangevarious models for medical applications various models for research and industry
Markerspassive and active markers, sterile and non-sterileactive markers, non-sterile

To find out more, please go to the website of our parent company

Northern Digital Inc. →