Hi, I would like to ask you if PIVlab algorithm perform the normalization of the cross correlation function using FFT multipass algorithm. In fact reading the paper of Dr. Thielicke it seems that the normalization is not performed. Reading other paper (as H Huang et al., On errors of digital particle image velocimetry, 1997) I found that ''normalized eq. is considerably more difficult to implement using the FFT'' so I hypothesized that it is not implemented. Can anybody help me please? Thank you very much for your attention.