
%0 Journal Article
%A Craig, M. 
%A Dickson, B. 
%A Rodrigues, S. 
%T Correcting aerial gamma-ray survey data for aircraft altitude
%J Exploration Geophysics
%D 1999/12/01
%V 30
%N 4
%P 161-166
%K 
%R https://doi.org/10.1071/EG999161
%U https://www.publish.csiro.au/paper/EG999161 
%X 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, two-dimensional 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. 
