MAGKETIC NOISE SUBSTRACTION 13'ITH WAVELET PACKETS
Brest Cedex · 1996
This work deals with the rebuilding of a transient signal produced by a moving ferromagnetic mas into the earth's magnetic field. The magnetic field is measured by four scalar magnetometers arranged in a square whch side is 2 km long. If the mass is moving in the vincinity of one of the sensors it is sure that the signal IS only present on this sensor. The natural variations of the earth's magnetic field is the noise which we want to eliminate. To De-Noise our signal we use the Wavelet Packets Decomposition and we implement some methods to threshold and shrink the coefficients obtained. We will first show the signals. In a second part we will discuss about the de-noising process. Finally, we will present the results of the research. 1. THE SIGNAL