A new signal processing analysis, based on the wavelet transform has been developed. It allows the detection and the reconstruction of fine structures in a very noisy signal. It removes the noise and gives a quantified level of detection of the structures against chance fluctuations. This powerful method has been applied on the PPS Voyager 2 data on the Uranus rings. A preliminary catalog of structures found in the $\sigma$ Sagitarii occultation experiment, is proposed here.