Phase correction is chosen so that the obtained wavelet is symmetric about its maximum. This operation is an approximation of the fact that the originating wavelet is causal.

The Hilbert transform is used to modify the phase of the wavelet . A phase correction of 120° allows us to obtain a zero phase wavelet. The first arrival associated with the direct wave is now concentrated on one positive arch (shown in red). As a consequence, it is easier to identify the oblique arrivals associated with reflected or diffracted waves, notably in the neighborhood of the 100th abscissa.