Hi Mirko,
the NI Vision library in CVI offers different functions that should be helpful to your question in "Pattern Matching":
imaqLearnGeometricPattern (, IMAQ_NO_OFFSET, NULL, NULL, NULL);
imaqReadMultipleGeometricPatternFile (, NULL);
For more information about the elements of CurveOptions refer to the NI Vision for LabWindows/CVI Function Reference Help in the Vision Development Module Bookshelf. To access the bookshelf, select Start>>All Programs>>National Instruments>>Vision>>Documentation>>Search the NI Vision Bookshelf..
regards,
Nikolai