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RTSS Videoextensometer - Contactless Strain Sensor for Material testing

Precise and flexible

With the RTSS video extensometer, longitudinal strain and transverse strain are measured contactlessly during material testing.

The optical strain sensor is used in tensile, compression, fatigue and creep tests and is suitable for flat samples, round samples, wires, reinforcing steel, etc.
The system is used at field of views from 5mm (micro tensile test) up to 5m (rope test). Strains from 0.0005% to 1000% can be measured.

Additional measuring modules for determining strain distribution, crack length, etc. are also available.
The modular RTSS system can be upgraded to a Q400 2D or 3D DIC system.

  RTSS Videoextensometer as strain sensor for material tests and tensile tests


checkmark   For static and dynamic tests up to VHCF

checkmark   Quick and simple specimen marking

checkmark   Strain measurement range from 0,0005% to 1000%

Compatible to universal test machines (UTM)

The RTSS (Real Time Strain Sensor) can be integrated via different interfaces as a strains sensor and can be used with any test machine on the market.
We would be happy to advise you on the possibilities and advantages of modernizing your testing machine with an RTSS video extensometer.


Advantages of the RTSS Videoextensometers

  • Fast setup and easy specimen marking
  • Flexible field of view from a few mm to some m
  • Compatible for all tensile test machines
  • Independent of the material
 RTSS videoextensometer for longitudinal and transversal strain measurement during tensile tests
Simultaneous measurement of longitudinal and transversal strain.



Contact less

No clamping =no mechanical influence of a mechanical sensor to the specimen:
    • High precision
    • No specimen influence/damage
Measurement of the strain at failure (no mechanical limitation of the sensor)

Material independent

Wide application field on all materials
Soft and rigid materials can be tested
Strains from 0,0005% (=5µm/m) to 1000%

Flexible field of view

Specimen size of a few mm to some m
For strains from 20µm/m until 1000%
Used at small and large tensile test machines
One system for
   • Different testing machines in one laboratory
   • Different tasks


Easy specimen marking
Can be used for tiny specimen due to enlarged image visualisation
Recording of movies for documentation and quality control
High precision, high speed
Simultaneous measurement of longitudinal and transversal strain


Fast system setup
Precise specimen alignment

Different data interfaces  

Compatible to all tensile test machines
Fully integrated with tensile test machines
Analogue or digital data interface to test machine
Usual data logging and determination of material properties (e.g. Young's module) by the tensile test software
Automatic control through tensile test machine/software


Quick and precise system calibration
Testing according to standards without mechanical sensor tracking


Technical Specifications


RTSS_Cx: High resolution video extensometer for quasistatic tensile tests.
Measurement resolution for strain down to 5µstrains (=5µm/m)

RTSS_HS: Fast video extensometer for dynamic tests.
The high measurement rate makes the system suited for dynamic applications (e.g. on a Hydropulser) and for the control of fast test.

RTSS_CREEP Simultaneous measurement of up to 10 specimen with a single high resolution camera that captures all specimen at the same time.
This system is typically used for crep testing applications..

Multi-camera-Systems: Multi camera setups for:
  1. Simultaneous measurement of different specimen sides.
  2. Combination of a small and a large field of view → High precision measurement of E-modulus and measurement of the complete Force-Strain-curve.
  3. Stereo Setup: Two cameras at a defined l0 distance measure. Each camera has a small field of view and measures one marker → Highest precision for rigid materials (small strains).


Specifications \ System RTSS_C1 RTSS_C05 RTSS_C02 RTSS_HS
Precision class (ISO9513)
at 100mm FOV*
1 0,5 0,2 1
Strain resolution 0.002% 0.001% 0.0005% ca. 0,002%
Distance resolution
at 100mm FOV*
1µm 0,5µm 0,2µm 1µm
Gauge length L0 10-1000mm 10-1000mm 10-1000mm 10-200mm
Measurement rate up to 100Hz up to100Hz up to 100Hz up to 1000Hz

*FOV=Field of View=image width. The FOV can be adjusted through different lenses.

We configure also individual systems for special applications.


The RTSS Videoextensometer is used as strain sensor

  • with universial tests machines for the measurement of
    • Young's modulus ISO 527-1
    • Poisson number ISO 527-1
    • R/N values ISO 10113, ISO 10275
    • Elongation at break
  • at fatigue tests
  • at vibration tests
  • Sheet testing ASTM E345, DIN 50154, ASTM E517, ASTM E646
  • rubber ISO 37
  • Composite materials ISO 527-4/-5
  • Foils ISO 527-3
  • Geo textiles, -grids ISO 10319
  • Polymers ISO 527
  • Metal and wire ISO 6892
  • Rope testing

To the list of scientific articles in which the RTSS system was used.


Software Functionality


Flexibly configurably real time measurement software
Modern User interface

  • Short training time due to easy and intuitive user interface
  • Definition of templates allows quick switching for different test set ups

Multi-Core Support

  • Low CPU load
  • The RTSS software cab run simultaneously on the control computer of the test machine.
 Istra4D Optional post-processing software for
  • full field strain measurement
  • crack propagation and crack length measurement


Applications Material Testing


Do you have questions related to our
products or services ?

Tel +49 (0) 2151 36528 00

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