MTS Fundamental Video Extensometer - Manual (Page 27)

Starting the Video Extensometer
Fundamental Video Extensometer 27
To carry out a test, three essential stages must be followed:
Note In the procedure is automatic, the first two operations are carried out
consecutively, if the manual search of the markers is not checked.
• The first step is the image optimization, which can be carried out in an
automatic manner (using the Optimize the image button) or manual manner.
In the case of the manual adjustment, contrast and brightness are the two
main factors of a good optimization. The adjustment allows you to obtain a
good contrast between the markers and the background.
• The second step is the search of the markers; As for the optimization, this
step can be carried out automatically or manually. In the case of a manual
adjustment, the objective is to determine the approximate area of the
markers.
• The last step is the initialization of the test. Click on the Initialize button to
start the measurement(s) of L0 on 100 images, then check if the strains
calculated in the window Information of strain are correct. Finally, click on
Reduce; a small window appears displaying the images and the distances
between markers currently noted which are represented by lines of different
colors depending on the strain.