Simultaneous interpolation, edge padding and denoising method for gravity data based on the projection onto convex sets
【Abstract】Gravity exploration blocks are often irregular, which causes the vacancy in the acquired gravity data. Before the processing and transformation of gravity data in wavenumber domain, the original data must be interpolated and processed with edge padding. High-frequency noise in gravity data is the main factor which causes the instability in later processing. Conventional gravity data processing generally performs interpolation, denoising and edge padding independently. These three issues were considered integrally, and an iterative method for simultaneous interpolation, denoising and edge padding of gravity data based on the projection onto convex sets was proposed. Firstly, the final cutoff wavenumber of the iterative method was determined through calculating and fitting the radial average power spectrum of the gravity data. Secondly, interpolation, edge padding and denoising were applied to gravity data using the spectrum with the wavenumber lower than the cutoff wavenumber, until the preset iteration number was reached. Theoretical gravity model test and the application in real isostatic gravity data acquired in Afghanistan showed that the method proposed is simple theoretically and convenient to be applied. The splicing of the interpolation and edge padding results is smooth without distortion, and the method achieved good interpolation and denoising effect. The results of the method proposed in this paper are better, compared with those of the conventional joint processing method based on minimum curvature, Kriging interpolation, wavelet denosing and cosine edge padding.
【Keywords】 gravity data; projection onto convex sets; denoising; interpolation; edge padding;
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