Analysis of peak-locking errors:

Since the intercorrelation function is determined on the discrete pixels, the determination of its maximum is biased toward integer values. This shows up in the global probability density function of the displacements, which displays local maxima at integer values, see example in fig. 11.

Figure 11: Probability density function of displacements obtained by CIV. To get a good statistics, we have sorted in bins of 0.1 pixel, the 50x50 x-displacements from a set of ... images (corresponding to the instability of a vortex).

We can estimate the peak locking error from such a pdf.