1. College of Sciences, North China University of Technology, Beijing 100144, China 2. China Aero Geophysical and Remote Sensing Center for Natural and Resources, Beijing 100083, China
Filtering is one of the crucial technologies for data processing in airborne gravimetry. Aimed at the wavelet filtering especially, the authors developed the wavelet low-pass filter for data processing in this paper. Based on the wavelet packet analysis, the wavelet packet tree was optimized according to the signal frequency range of corresponding estimated wavelet packet decomposition level, the desired low-pass cutoff frequency and the node’s arranged order on the basis of the “frequency” order of the wavelet packet coefficients from the low frequencies to the high frequencies. The main characteristics of the orthogonal or the biorthogonal wavelets were analyzed, and the new threshold processing schemes were proposed in this paper, The authors made the experimental researches on filtering GT-airborne gravity data using the wavelet filter. The results show that the discrete Meyer wavelet’s filtering has achieved the best effect among the wavelets available, and this wavelet filter for airborne gravity data has almost as good satisfactory filtering effect as GT-1A result, with the root-mean squared difference between 0.2 mGal and 0.3 mGal in comparison with GT-1A result.
Guo Z H, Luo F, An Z F . Experiment researches on FIR low pass digital filters based on window functions of airborne gravity data[J]. Geophysical and Geochemical Exploration, 2007,31(6):568-571.
Guo Z H . The method and technology research of airborne gravity survey and data processing[R]. “Hundred People Plan” Project Research Report. Beijing: Ministry of Land and Resources of the People’s Republic of China, 2008.
[4]
王静波 . 航空重力测量数据处理方法技术研究[D].北京:中国地质大学(北京), 2010.
[4]
Wang J B . Methodologies and technology of data processing for airborne gravimetry[D]. Beijing: China University of Geosciences(Beijing), 2010.
Xiong S Q, Zhou X H, Guo Z H , et al. Theory, methods and application of the airborne gravity prospecting[M]. Beijing: Geological Publishing House, 2010.
Wang J B, Xiong S Q, Guo Z H , et al. Research on methods of estimating airborne gravity anomaly[J]. Geophysical and Geochemical Exploration, 2011,35(4):493-498.
Guo Z H, Luo F, Wang M , et al. The design and experiment of IIR low pass digital filters for airborne gravity data[J]. Chinese J. Geophys., 2011,54(8):2148-2153.
Luo F, Guo Z H, Luo Y , et al. Experimental researches on fir lowpass filter based on equiripple[J]. Geophysical and Geochemical Exploration, 2012,36(5):856-860.
[10]
阮秋琦 . 数字图象处理学[M]. 北京: 电子工业出版社, 2001.
[10]
Ruan Q Q. Digital image processing[M]. Beijing: Publishing House of Electronics Industry, 2001.
Luo F, Guo Z H, Wang M , et al. Experimental reseaches on the theshold of airbone gravity data denoising based on DB wavelet transfom[J]. Geophysical and Geochemical Exploration, 2013,37(4):645-654.
Sun Z M, Zhai Z H . Filtering of the airborne gravity data by wavelet thresholding[J]. Geomatics and Information Science of Wuhan University, 2009,34(10):1222-1225.
Li S Y, Lin J, Yang G H , et al. Ground-airborne electromagnetic signals de-noising using a combined wavelet transform algorithm[J]. Chinese J. Geophys. , 2013,56(9):3145-3152.
Zhang Z T, Zhu J J, Kuang C L , et al. Multi-threshold wavelet packet de-noising method and its application in deformation analysis[J]. Acta Geodaetica et Cartographica Sinica, 2014,43(1):13-20.
Wu J Z, Hua X H, Gao J Q . Feature extraction of structure natural vibration and multipath separation based on wavelet packet decomposition[J]. Geomatics and information Science of Wuhan Univers, 2010,35(4):486-490.
Yan Y, Xing H Y . Sea clutter de-noising based on wavelet packet multi-threshold method[J]. Journal of Electronic Measurement and Instrumentation, 2018,32(8):172-178.
Lyu N N, Su S J, Zhai C R . Application of improved wavelet packet threshold algorithm in aibration signal denoising[J]. Journal of Detection & Control, 2018,40(1):119-123.
[23]
Katunin A . B-spline wavelet packets and their application in the multiresoluton non-stationary signal processing[J]. Scientifc Problems of Machines Operation and Maintenance, 2010,163(3):103-115.
[24]
李翔 . 基于小波分析的测量信号处理技术研究[D]. 哈尔滨:哈尔滨工业大学, 2009.
[24]
Li X . Research on measurement signal processing technology based on wavelet analyse[D]. Harbin: Harbin Institute of Technology, 2009.
[25]
Katunin A . The construction of high-order b-spline wavelets and their decomposition relations for faults detection and localization in composite beams[J]. Scientifc Problems of Machines Operation and Maintenance, 2011,167(3):43-59.