In three-dimensional space, we consider two homogeneous fluid media separated by a plane interface. In the lowest velocity media is located a point-source, which emits in time an arbitrary signal. The second medium contains the observation point. By analogy to a reconstruction formula of the wavelet transform, we have obtained for large radial distance, a formula for the reconstruction of the time dependence of the source-signal. This reconstruction involves an integration over depths (dilation parameter) of the transmitted pressure (wavelet coefficient) for each observation point. We show that the medium where are located the observation points can be approached by two series of filters. To link in future theoretical results obtained from an experiment, we consider the air-water interface.