Transient broadband electromagnetic detection signal processing method based on geological detection

Abstract

A broadband electromagnetic signal (20Hz-150kHz) processing technology based on geological detection comprises the following steps: adding white noise to an original signal, and performing normalization processing to obtain a new signal; according to envelope characteristics of noisy signals, performing empirical mode decomposition by applying an automatic shift method, a waveform matching methodor a proportional continuation method to obtain IMF components and residual components, wherein the IMF component changing fastest is firstly shifted out by the automatic shift method, and the IMF component of the broadband electromagnetic signals can be smoothed quickly along with increase of IMF levels; eliminating white noise in the IMF component to obtain a real IMF component; calculating thetime domain first-order differential energy, the phase first-order differential energy and the normalized energy proportion of each IMF, and selecting the IMF with the largest three features as the main feature of the radiation signal; and comparing the selected IMF frequency with the frequency of electromagnetic waves radiated by specific minerals, and if the selected IMF frequency is consistentwith the frequency of the electromagnetic waves radiated by the specific minerals, the minerals contain mineral elements.

Description

technical field [0001] The invention relates to the technical field of geological exploration, in particular to a data processing method for providing broadband magnetic field radiation signals produced by minerals in the earth's crust. Background technique [0002] Underground mineral magnetic field signals contain important characteristic information such as mineral distribution and geological structure, which can provide important reference guarantees for geological surveys. Therefore, the technology for detecting magnetic field radiation signals of various minerals has attracted much attention. Minerals are extruded during crustal movement, usually accompanied by magnetic field radiation signals that radiate to the surrounding space field in accordance with the law of the wave equation. This signal is a narrow bandwidth radiation signal, and it is mostly nonlinear and non-stationary. Broadband electromagnetic radiation signals carry important information such as mineral ...

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Problems solved by technology

[0015] Although the traditional time-frequency analysis method takes into account both the time domain and the frequency domain, there are also some fatal flaws that affect the actual use.

For example, the linear method based on kernel function decomposition is not suitable for analyzing multi-scale and mutation signals due to the fixed window or poor adaptability of the basis function, and the basis function of limited length will inevitably produce energy leakage and affect the resolution; There are serious cross-interference items in the quadratic time-frequency distribution method based on Wigner distribution. In order to suppress the inherent cross-item interference of the quadratic time-frequency distribution, it is usually necessary to achieve a certain compromise between resolution and cross-item interference, so it is inevitable destroys the concentration of the self-term components of the signal, resulting in a decrease in its resolution

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