Discrete Marker Tracking
3D Motion Analysis by Discrete Marker Tracking
When characterizing the mechanical response of a product, component or assembly under load, it is often required to analyse the 3D motion of certain sub-components. Rather than visualizing results in a full-field mode, displacements and rotations can be calculated by tracking discrete markers applied at the location of interest. It provides you with accurate measurements of the motion components in a three dimensional measurement volume independent of the object size.
Advanced motion analysis features:
- 3D coordinates and relative points positions
- 3D displacements and rotations
- 3D velocities and accelerations
- Video extensometry
Markers can be easily applied to the surface of the object and allow for a contactless measurement independent of the type of material or the environmental conditions. It offers a stable solution for the analysis of materials and components when loaded statically or dynamically. For dynamic loading events the markers are tracked using high speed cameras which can capture up to 500,000 images in one second.
The image recording can be fully synchronised with other external signals, for example force or torque measurements comming from a load or rotary torque cell. The resolution of the method lies in the sub-micrometer range. High accurate results are obtained due to an extensive calibration procedure and optical system parameter optimization. A lens calibration is performed for every setup to compensate for lens inaccuracies and possible distortions.
Markers can also be used for precise coordinate system alignment with external reference coordinate systems in CAD models or FE models.
Application Example: Marker Tracking on Textile Material
Two sets of markers were tracked during the tensile loading of a textile material. In this case the relative displacements of the horizontal and vertical set of markers were used to calculate strains (virtual extensometer).