Transient electromagnetic signal noise separation and recognition method based on improved variational mode decomposition

Abstract

The invention discloses a transient electromagnetic signal noise separation and recognition method based on improved variational mode decomposition, which comprises the steps of: carrying out the global search and optimization of a mode number K and a penalty factor alpha in a variational mode decomposition algorithm through employing a whale optimization (WOA) algorithm to obtain an optimal parameter combination; carrying out variational mode decomposition (VMD) on a transient electromagnetic signal by utilizing the obtained optimal parameter combination to realize signal-to-noise separation;and identifying a noise mode in a mode component through an improved Bhattacharyya distance algorithm to realize noise elimination. According to the optimization method, parameter setting is simple,required operators are few, and the workload of a traditional optimization method is greatly reduced; transient electromagnetic signals can be decomposed into a series of modal components with frequencies from low to high more accurately according to optimized parameters, and the modal aliasing problem caused by traditional artificial subjective parameter selection is greatly reduced; and the calculation is simple and convenient, the identification is convenient, and subsequent signal reconstruction is facilitated.

Description

technical field [0001] The invention relates to the technical field of signal processing, and more specifically, to a method for separating and identifying transient electromagnetic signal noise based on improved variational mode decomposition. Background technique [0002] As a mature and rapid exploration method, transient electromagnetic method (TEM) is widely used in many fields such as resource exploration, geological research, environmental investigation and archaeological exploration. In particular, great progress has been made in mapping groundwater and locating mineral resources, fully meeting the world's growing demand for mineral resources and groundwater. Different from other signals, transient electromagnetic signal is a nonlinear and non-stationary signal, and the late signal is very weak. During the measurement process, the transient electromagnetic secondary field signal received by the coil is inevitably disturbed by natural and man-made noise, which covers...

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Problems solved by technology

For example, the selection of modal number K and penalty factor α is very important to the decomposition results. However, the current selection of these two parameters mainly depends on human experience selection or manual trial and error selection, which not only wastes time but also consumes manpower, and the result is also very subjective. , the optimal decomposition cannot be achieved, resulting in the mixing of noise and effective signal, affecting the separation and identification of noise

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