Abstract：Because natural source super low frequency (SLF) electromagnetic detection equipment receives wideband multi-source signal, how to decompose the signal to filter out the interference signal was a key factor for the application of natural source SLF electromagnetic detection technology. In the present article, the detection equipment developed by Peking University was used to survey the coal bed methane data in the Qinshui basin, Shanxi province, and the curvelet transform method was employed to decompose those data. The analysis results indicated that the high-frequency information coming from the decomposition is the interference signals mainly generated by lightning in the atmospheric and directly received by the detection equipment, while the low frequency signal mainly contains the target information. So the reconstructed curve based on the low-frequency information was more favorable for the interpretation of the target, compared with the original spectrum curve. But the curvelet transform method could not remove the artificial frequency signal.
[1] ZHANG Ze-xun, HOU Gui-ting, QIN Qi-ming, et al(张泽勋, 侯贵廷, 秦其明, 等). Acta Scientiarum Naturalium Universitatis Pekinensis(北京大学学报·自然科学版)，2009, 45(2): 33. [2] Qin Q M, Ye X, Li B S,et al. 2007 IEEE International Geoscience and Remote Sensing Symposium, 2008. 4712. [3] YUE Qi-ming(岳棋明). Progress in Geophysics(地球物理学进展), 2004, 19(4): 873. [4] QIN Qi-ming, LI Bai-shou, CUI Rong-bo, et al(秦其明, 李白寿, 崔蓉波, 等). Chinese Journal of Geophysics(地球物理学报)，2010, 53(3)：685. [5] Qin Q M, Li B S, Ye X, et al. International Society for Photogrammetry and Remote Sensing, 2008. 1183. [6] LI Bai-shou, QIN Qi-ming, JIANG Hong-bo, et al(李白寿, 秦其明, 蒋洪波, 等). Earth Science Frontiers(地学前缘), 2010, 17(3): 259. [7] LI Pei-jun, JIN Hui-ran, SONG Ben-qin(李培军, 金慧然, 宋本钦). Acta Scientiarum Naturalium Universitatis Pekinensis(北京大学学报·自然科学版)，2008, 44(4)：45. [8] Candes E J, Donoho D L. Van-Derbilt TN: University Press, 1999. [9] Donoho D J, Duncan M R. SPIE, 2000, 4056: 12. [10] Candes E J, Donoho D L. Communications on Pure and Applied Mathematics, 2004, 57(2): 219. [11] Candes E J, Donoho D L. Applied and Computational Harmonic Analysis, 2005, 19(2): 162. [12] Candes E J, Donoho D L. Applied and Computational Harmonic Analysis, 2005, 19(2): 198. [13] LI Ming-zhai(李明宅). Natural Gas Industry(天然气工业), 2000, 20(4):24. [14] YE Jian-ping, PENG Xiao-mei, ZHANG Xiao-peng(叶建平, 彭小妹, 张小朋). China Coalbed Metthane(中国煤层气)，2009, 6(3): 7. [15] HU Wen-rui, ZHAI Guang-ming, LI Jing-ming(胡文瑞, 翟光明, 李景明). Engineering Sciences(中国工程科学)，2010, 12(5): 25.
