Video extensometer
The video extensometer principle is based on tracking marks applied to the surface of the specimen. The video camera used as an extensometer automatically detects the light-to-dark transitions on the specimen surface and tracks these during deformation.

The video extensometer provides non-contact, high-resolution measurement of tensile and compressive deformations on all types of plastics, metals, rubber, composites and films. It is also suitable for recording transverse strain, r & n-values and offset yields in tensile tests.
• ideal strain measurement system for materials prone to whipping (safety belts, steel ropes, rubber ropes etc.)
• flexible illumination system (incident light / reflected light) can be adjusted to provide optimum lighting for the current testing situation
• suitable for use with temperature chambers with plane-parallel glass insert with heated pane
• high resolution and measurement accuracy for all image sizes
• simultaneous measurement of axial and transverse strain is possible
• no separate markings are required for transverse strain measurement; width can be determined at one or more locations
• determination of r & n-values to ISO 10113 and ISO 10275 and offset yield in tensile tests to EN 10002-1
• measurement travel can be varied and (depending on image size or lens selected) is very long
• automatic gauge-mark recognition and recording of initial gage-length L0
• Accuracy Class 1 (field of view ≤ 200 mm) to EN ISO 9513 and Accuracy Class 2 to EN ISO 9513 (with 8 mm lens or field of view > 200 mm)
• entire test sequence can be followed on-screen and the video sequence saved for subsequent evaluation
• pattern recognition
• strain distribution
• video capturing