GOM detection of reference point markers

[[Hu...]]

Hi, 

 

I am trying to get a better understanding behind the algorithms and math behind some of the functions in GOM correlate professional. 

I have been using reference point markers and speckle pattern to detect the deformation. 

How does the GOM software detect the reference point markers (edge detection?? blob analysis??) ,  how does it create displacement vectors and full-field displacement fields? 

Can someone help me to answer some of the questions or redirect me to a source where i can read about?  

 

Thanks ! 

Best regards, 

Huda 

[[Iv...]]

Hi Huda,

the reference points are found with a grayvalue detection. The SW checks within the whole image the grayvalues and searches for a grayvalue behaviour like the reference points (dark circular edge and an inner bright circle/ellipse). Afterwards it fits an ellipse into the shift of the bright and dark grayvalue on the point and creates the 3D coordinate roughly in the gravity of the inner ellipse. On a stochastic pattern the SW creates facets such as seen in the preview of the surface component and track the 3D coordinate over the gravity of the facet. 

The displacement is calculated while checking the changes of the 3D coordinate from the reference stage to the current stage. 

I hope this helps. 

Greetings, Ivan