/>Full waveform inversion (FWI) requires a good estimation of the source wavelet. However, the accuracy of the obtained source wavelet from field data often cannot be guaranteed. The non-repeatability of seismic wavelets in time-lapse processing makes the source-wavelet estimation for the baseline and monitor-line surveys even more challenging. To address this problem, we incorporate source-independent methodology into the current time-lapse FWI workflow for VTI media. The figure shows that the time-lapse variations can be reconstructed even using the wrong source wavelet, and the resolution can be as good as that using the true source wavelet.