- Volume 2 Issue 2
We have studied a denoising technique involving wavelet transform for improving the quality of geophysical data during the preprocessing stage. To assess the effectiveness of this technique, we have made synthetic data contaminated by random noises and compared the results of denoising with those obtained by conventional low-pass filtering. The low-pass filtering of the sinusoidal signal having a sharp discontinuity between the first and last sample values shows apparent errors related to Gibbs' phenomena. For the case of bump signal, the low-pass filtering induces maximum errors on peak values by removing some high-frequency components of signal itself. The wavelet transform technique, however, denoises these signals with much less adverse effects owing to its pertinent properties on locality of wavelet and easy discrimination of noise and signal in the wavelet domain. The field data of gravity tide are denoised by using soft threshold, which shrinked all the wavelet coefficients toward the origin, and the G-factor is determined by comparing the denoised data and theoretical data.
- 응용지구물리학 민경덕;서정희;권병두
- 국방 대학원 석사학위 논문 PET 중력계를 이용한 G-인자 분석 박정환
- 63th Annual Internation Meeting Seismic data compression using wavelet transforms Bosman,C.;Reiter,E.
- WaveLab Reference Manual Buckheit, J.;Chen, S.;Donoho, D.L.;Johnstone, I.M.
- Proceedings IEEE Int. Conf. on Inform. Sci. Syst. Perfect channel splitting by use of interpolation/decimation/tree decomposition techniques Croisier, A.;Esteban, D.;Galand, C.
- Ten lectures on wavelets Daubechies, I.
- J. Am. Statist. Ass. v.90 Adapting to unknown smoothness via wavelet shrinkage Donoho, D.L.;Johnstone, I.M.
- J. R. Statist. Soc. B. v.57 Wavelet shrinkage asymptopia? Donoho, D.L.;Johnstone, I.M.;Kerkyacharian, G.;Picard, D.
- Geoexploration v.23 Cycle-octave and related transforms in seismic signal analysis Goupillaud, P.;Grossmann, P.;Morlet, J.
- SIAM J. Math. v.15 Decomposition of hardy functions into square integrable wavelets of constant shape Grossman, A.;Morlet, J.
- A Friendly Guide to Wavelets Kaiser, G.
- Geophsics v.61 Wavelet transform inversion with prior scale information Li, Xin-Gong;Sacchi, M. D.;Ulrych, T. J.
- Journal of Geophycial Research v.64 Formulas for computing the tidal accelerations due to the Moon and the Sun Longman, I.M.
- Wave packet transform and compression: 62nd Annual Internation Meeting Luo, Y.;Schuster, G. T.
- IEEE Trans. Pattern Anal. Machine Intell. v.11 A theory for multiresolution signal decomposition : the wavelet representation Mallat, S. G.
- A wavelet tour of signal processing Mallat, S. G.
- SIAM Review v.31 Wavelets and dilation equations: a brief introduction Strang, G.
- Wavelets and Subband Coding Vetterli, M.;Kovacevic, J.
- Geophysical Journal of International v.116 Detection of anomalous seismic phases by the wavelet transform Yomogida, K.