Related Experiment Videos
Accuracy of a video strain measurement system
W P Smutz1, M Drexler, L J Berglund
1Orthopedic Biomechanics Laboratory, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA.
Journal of Biomechanics
|June 1, 1996
Summary
This study validated a video system for measuring soft tissue strain, finding minimal static and dynamic errors. The system is accurate for most applications, with minor dynamic error increases at higher loading rates.
Area of Science:
- Biomechanics
- Biomedical Engineering
- Materials Science
Background:
- Accurate measurement of soft tissue strain is crucial in biomechanics.
- Existing video systems require validation for reliable strain analysis.
- Soft tissue mechanics research necessitates precise experimental methodologies.
Purpose of the Study:
- To determine the accuracy of a laboratory-used video system for soft tissue strain measurement.
- To quantify both static and dynamic errors associated with the video system.
- To establish the system's reliability under various experimental conditions.
Main Methods:
- Performed static and dynamic error analyses on a servo-hydraulic materials test machine.
- Utilized fluorescent markers attached to stationary and moving components.
- Investigated the influence of marker size, camera distance, and loading rates on system accuracy.
Main Results:
- Static error was independent of marker size.
- Dynamic error was independent of loading rate and marker size below 50% of camera field of view (CFV) per second.
- Marker size affected dynamic error at loading rates exceeding 50% of CFV per second.
Conclusions:
- The video system demonstrates high accuracy for soft tissue strain measurement.
- Mean static error was 0.026% of CFV, and mean dynamic error was 0.062% of CFV.
- The system's accuracy is reliable across a range of conditions, with considerations for high-speed dynamic testing.