Correcting aerial gamma-ray survey data for aircraft altitude

Maurice Craig; Bruce Dickson; Stewart Rodrigues

doi:10.1071/EG999161

ISSN: 0812-3985
E-ISSN: 1834-7533

Correcting aerial gamma-ray survey data for aircraft altitude
Authors Maurice Craig^a, Bruce Dickson^b and Stewart Rodrigues^c
View Affiliations Hide Affiliations

^a BHP Research and Technical Development, , GPO Box 86A, Melbourne Victoria, Australia, 3001, Phone: 61 3 9609 4477, Fax: 61 3 9609 4489, E-mail: [email protected] ^b CSIRO Exploration and Mining, , P.O. Box 136, North Ryde N.S.W., Australia, 2113, E-mail: [email protected] ^c CSIRO Exploration and Mining, Private Bag, P.O.Wembley W.A., , Australia, 6014, E-mail: [email protected]
Publisher: Australian Society of Exploration Geophysicists
Source: Exploration Geophysics, Volume 30, Issue 3-4, Sep 1999, p. 161 - 166
DOI: https://doi.org/10.1071/EG999161
- Published online: 01 Sep 1999

Abstract

In their ascent to the aircraft detector system, the gamma-rays recorded in airborne radiometric surveys are attenuated, first by the surface materials wherein they originate, then by the intervening atmosphere. Increased ground-clearance thus entails reduced count-rates. It also implies diminished spatial resolution, because the same cone of incident radiation derives from progressively larger ‘footprints’ that, for a given sampling rate, increasingly overlap. But suitable post-processing of the gridded, twodimensional imagery can be used to correct these types of height-dependent degradation and hence produce sharper, quantitatively useful maps of radioactive isotope distribution. An essential prerequisite for such inverse filtering is noise-suppression, achieved here through maximum-noise-fraction (MNF) transformation of multi-channel data. High-frequency noise amplified by the deconvolution step is brought under control by a variant of Wiener filtering. The combined de-noising and deconvolution process is illustrated by application to an airborne gamma-ray survey from the Marble Bar area, Western Australia.

Article metrics loading...

/content/journals/10.1071/EG999161

1999-09-01

2026-01-13

From This Site

/content/journals/10.1071/EG999161

dcterms_title,dcterms_subject,pub_keyword

-contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution

10

5

Full text loading...

References

Billings, S., 1998, Geophysical aspects of soil mapping using airborne gamma-ray spectrometry: PhD thesis, The University of Sydney (unpublished).
Billings, S. and Hovgaard, J., 1999, Modeling detector response in airborne gamma- ray spectrometry: Geophysics, 64, (in press).
Briggs, I. C., 1974, Machine contouring using minimum curvature: Geophysics, 39, 39-48.
Craig, M., 1993, The point-spread function for airborne radiometry: Math. Geol., 25, 1003-1013.
Dickson, B.L. and Taylor, G., 1998, Noise reduction of aerial gamma-ray surveys: Explor. Geophys. 29, 324-329.
Dines, K. A. and Kak, A. C., 1977, Constrained least squares filtering: IEEE Trans. on Acoustics, Speech and Signal Processing, 25, 346-350.
Grasty, R. L., 1979, Gamma ray spectroscopic methods in uranium exploration - theory and operational procedures: in J. Hood (Ed.), Geol. Survey of Canada Economic Geology Report 31: Ottawa, Canada, 147-161.
Green A. A., Berman, M., Switzer, P. and Craig, M. D., 1988, A transformation for ordering multispectral data in terms of image quality with implications for noise removal: IEEE Trans. Geosci. and Remote Sensing, 26, 65-74.
Gunn, P. J., 1975, Linear transformations of gravity and magnetic fields: Geophys. Prosp., 23, 300-312.
Gunn, P. J., 1978, Inversion of airborne radiometric data: Geophysics, 43, 133-142.
Gunn, P.J. and Almond, R., 1997, A method for calculating equivalent layers corresponding to large aeromagnetic and radiometric grids: Explor. Geophys., 28, 72-79.
Huang, T. S., Schreiber, W. F. and Tretiak, O. J., 1971, Image processing: Proc. IEEE, 59, 1586-1609.
Hunt, B. R., 1972, Deconvolution of linear systems by constrained regression and its relationship to the Wiener theory: IEEE Trans. Automat. Control, 17, 703-705.
Hunt, B. R., 1973, An application of constrained least squares estimation to image restoration by digital computer: IEEE Trans. Comput., 22, 805-812.
IAEA, 1991, Airborne gamma-ray spectrometer surveying: Internat. Atomic Energy Agency, Technical Report Series, No 323.
Minty, B. R. S., 1997, Fundamentals of airborne gamma-ray spectrometry: AGSO Journal of Australian Geology and Geophysics, 17, 39-50.
Neumayr, P., Ridley, J.R., McNaughton, N.J., Kinny, P.D., Barley, M.E., and Groves, D.I., 1998, Timing of gold mineralization in the Mt York district, Pilgangoora Greenstone Belt, and implications for the tectonic and metamorphic evolution of an area linking the western and eastern Pilbara Craton: Precambrian Research 88, 249-265.
Rosenfeld, A. and Kak, A. C., Digital Picture Processing, 2nd Ed., vol. 1. Academic Press, Orlando, 1982, 435 p.
Twomey, S., 1965, The application of numerical filtering to the solution of integral equations encountered in indirect sensing measurements: J. Franklin Inst., 279, 95109.

/content/journals/10.1071/EG999161

Article Type: Research Article

Keyword(s): Deconvolution; gamma-radiometry; inverse filtering; Wiener filter

Most Cited This Month Most Cited RSS feed

- A comparison of smooth and blocky inversion methods in 2D electrical imaging surveys
  
  Authors M.H. Loke, Ian Acworth and Torleif Dahlin
- Reverse-Time Migration using the Poynting Vector
  
  Authors Kwangjin Yoon and Kurt J. Marfurt
- SkyTEM–a New High-resolution Helicopter Transient Electromagnetic System
  
  Authors K. I. Sorensen and Esben Auken
- An overview of a highly versatile forward and stable inverse algorithm for airborne, ground-based and borehole electromagnetic and electric data
  
  Authors Esben Auken, Anders Vest Christiansen, Casper Kirkegaard, Gianluca Fiandaca, Cyril Schamper, Ahmad Ali Behroozmand, Andrew Binley, Emil Nielsen, Flemming Effersø, Niels Bøie Christensen, Kurt Sørensen, Nikolaj Foged and Giulio Vignoli
- The Fast Marching Method: An Effective Tool for Tomographic Imaging and Tracking Multiple Phases in Complex Layered Media
  
  Authors Nicholas Rawlinson and Malcolm Sambridge
- 3-D Analytic Signal in the Interpretation of Total Magnetic Field Data at Low Magnetic Latitudes
  
  Authors Ian N. MacLeod, Keith Jones and Ting Fan Dai
- CMP cross-correlation analysis of multi-channel surface-wave data
  
  Authors Koichi Hayashi and Haruhiko Suzuki
- A new direct non-invasive groundwater detection technology for Australia
  
  Authors M. Schirov, A. Legchenko and G. Creer
- 3D inversion of airborne electromagnetic data using a moving footprint
  
  Authors Leif H. Cox, Glenn A. Wilson and Michael S. Zhdanov
- Notes On Rock Magnetization Characteristics In Applied Geophysical Studies
  
  Authors D. A. Clark and J. B. Emerson
More Less

Correcting aerial gamma-ray survey data for aircraft altitude

Abstract

Most Read This Month

Most Cited This Month Most Cited RSS feed