Inversion of Resistivity Data Considering Data Noise

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2009 Vol.46, Issue 5 Preview Page Next Page

Inversion of Resistivity Data Considering Data Noise 잡음을 고려한 전기비저항 탐사 자료의 역산: 안동국, 조인기
An, Dong-Kuk and Cho, In-Ky

31 October 2009. pp. 546-552

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Abstract

The major sources of noise in DC resistivity measurement are high contact resistance, measurement errors, and sporadic background noise. Accurate quantification of data noise is crucial to prevent misinterpretation of resistivity data. Stacking repeated measurements is useful for minimizing random errors. Reciprocal measurements can provide a measure of data precision. Stacking and reciprocal measurements are both useful in estimating noise. Fortunately, most of modern resistivity devices measures standard deviation of data noise. However, the measured noise, especially in Korea, has generally been used only for the data quality control in the data acquisition stage. In this study, we propose a noise estimation and data weighting method according to noise level. Through numerical tests, we assure that accurate noise estimation and data weighting according to noise level effectively suppress the effects of noise without degrading resolving power.

Keywords

Resistivity

Noise

Data weighting

전기비저항 탐사에서 잡음원은 높은 접촉저항, 장비의 측정오차 및 주변의 불규칙한 잡음을 들 수 있다. 전기비저항 탐사 자료의 올바른 해석을 위해서는 이들 잡음의 정확한 추정이 필요하다. 반복성시험은 불규칙 잡음을 억제하는데 효과적이며, 상반성시험은 측정자료의 정밀도를 제공해 준다. 또한 이들 반복성시험과 상반성시험은 잡음의 측정에 매우 효과적이다. 최근 전기비저항 탐사기기들은 잡음자료의 표준편차를 제공한다. 하지만 국내의 경우 이 잡음을 현장자료획득 단계에서 자료의 질을 평가하는데 사용하는데 그치고 있다. 본 연구에서는 정확한 잡음측정방법과 잡음수준에 자료가중값을 결정하는 방법을 제안하였다. 수치실험을 통하여 정확한 잡음측정과 잡음에 따른 가중값을 사용할 경우 역산의 분해능 저하 없이 잡음의 영향을 효과적으로 억제할 수 있음을 확인하였다.

키워드

전기비저항

잡음

자료가중

References

Binley, A., Ramirez, A., and Daily, W., 1995, “Regularised image reconstruction of noisy electrical resistance tomography data,” The 4th workshop of the European Concerted Action on Process Tomography, Bergen, Norway.
Constable, S. C., Parker, R. L., and Constable, C. G., 1987, “Occam’s inversion: a practical algorithm for generating smooth models from EM sounding data,” Geophysics, Vol. 52, pp. 289-300.
LaBrecque, D., J., Miletto, M, Daily, W., Ramirez, A., and Owen, E., 1996, “The effects of noise on Occam’s inversion of resistivity tomography data,” Geophysics, Vol. 61, pp. 538-548.
Menke, W., 1984, Geophysical data analysis: Discrete inverse theory, Academic Press Inc. Slater, L., Binley, A., Cassiani, G., Birken, R., and Sandberg, S., 2002, “A 3D study solute transport in a large experimental tank,” Journal of Applied Geophysics, Vol. 49, pp. 211-229.
Slater, L., Binley, A. M., Daily, W., and Johnson, R., 2000, “Cross-hole electrical imaging of a controlled saline tracer injection,” Journal of Applied Geophysics, Vol. 44, pp. 85-102.
Yi, M. J., Kim, J. H., and Chung, S. H., 2003, “Enhancing the resolving power of least-squares inversion with active constraint balancing,” Geophysics, Vol. 68, pp. 931-941.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society for Geosystem Engineering
Journal Title(Ko) :한국지구시스템공학회지
Volume : 46
No :5
Pages :546-552

[1] Binley, A., Ramirez, A., and Daily, W., 1995, “Regularised image reconstruction of noisy electrical resistance tomography data,” The 4th workshop of the European Concerted Action on Process Tomography, Bergen, Norway.

[2] Constable, S. C., Parker, R. L., and Constable, C. G., 1987, “Occam’s inversion: a practical algorithm for generating smooth models from EM sounding data,” Geophysics, Vol. 52, pp. 289-300.

[3] LaBrecque, D., J., Miletto, M, Daily, W., Ramirez, A., and Owen, E., 1996, “The effects of noise on Occam’s inversion of resistivity tomography data,” Geophysics, Vol. 61, pp. 538-548.

[4] Menke, W., 1984, Geophysical data analysis: Discrete inverse theory, Academic Press Inc. Slater, L., Binley, A., Cassiani, G., Birken, R., and Sandberg, S., 2002, “A 3D study solute transport in a large experimental tank,” Journal of Applied Geophysics, Vol. 49, pp. 211-229.

[5] Slater, L., Binley, A. M., Daily, W., and Johnson, R., 2000, “Cross-hole electrical imaging of a controlled saline tracer injection,” Journal of Applied Geophysics, Vol. 44, pp. 85-102.

[6] Yi, M. J., Kim, J. H., and Chung, S. H., 2003, “Enhancing the resolving power of least-squares inversion with active constraint balancing,” Geophysics, Vol. 68, pp. 931-941.

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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