Leveling aerogeophysical data using a moving differential median filter

Abstract

We describe a new technique that can be used to level data collected along regular and irregular line patterns with or without tie-line control. The technique incorporates a moving differential median filter to minimize line-level errors, to level survey-line data, and to microlevel data with no tie-line control. This overcomes the problem of standard leveling methods that lose their effectiveness with irregular flight patterns. To validate the method, we use it to level very-low-frequency (VLF) electromagnetic (EM) data from a helicopter survey where flight lines are parallel. Leveling is also performed on a set of vintage aeromagnetic data from the North Sea, gathered from nonparallel flight lines. Results show that the differential median filter leveling technique is superior to the standard leveling method because it results in fewer line errors and less distortion of high-wavenumber anomalies when processing irregular survey lines, making the method suitable for a wide variety of data sets. © 2006 Society of Exploration Geophysicists. All rights reserved.