Abstract:

Morphology filtering based on mathematical morphology as a nonlinear signal processing method has demonstrated its value in magnetotelluric time-domain signal de-noising. But morphology filtering remove the steep-gentle changing of magnetotelluric time-domain signal which also contains useful information while remove the noise waveform of magnetotelluric time-domain signal. To solve this problem, the authors present a scheme based on top-hat transformation of mathematical morphology in noise suppression of magnetotelluric time-domain signal, using the ability of top-hat transformation on detecting peaks or troughs and flat structural elements to remove the noise from magnetotelluric time-domain signal. The results of processing measured magnetotelluric sounding data collecting from Lujiang-Zongyang ore concentration area by the proposed method show that the proposed method can remove noise waveform while reserving the steep-gentle changing of time-domain signal, restore the magnetotelluric time-domain signal contaminated by noise and improve the quality of magnetotelluric apparent resistivity curve.

Key words: electromagnetic prospecting, magnetotelluric, top-hat transformation, strong interference separation, Lujiang-Zongyang ore concentration area