Application of Enhancement and Filtering Technique to Aeroradiometric data of Ogun State, South-Western, Nigeria
Publication Date : 23/05/2022
Enhancement and filtering primarily design for potential field problem have gained more importance in the recent time since it can now be successfully applied to non-potential field data. They are found mostly applicable for smoothing, noise reduction and in source edge detection. In this study, these techniques were applied to airborne radiometric data (non-potential field) of Ogun State, in order to identify some areas which are subtle for radioelement deposition and possible geomorphic activities attached. Three enhancement techniques, namely; Analytical Signal Amplitude (ASA), Horizontal Gradient Magnitude (HGM) and Tilt Derivatives (TDR) were used. Filtering techniques such as Upward Continuation, Low Pass and High Pass Filter were as well employed. The result obtained shows variation in the responses of radiometric flux for different enhancement techniques with respect to the geological and bedrock composition. ASA and HGM revealed unique similar trend in the radioelement distribution compared to TDR. Upward continuation distance at 100 and 1000m was demonstrated to investigate the magnitude of enhancement or attenuation of the radioelements and their total count. Low pass (regional) filter results revealed the amplitude of radioelement to approach the original value while that of high pass (residual) filter approaches zero. High pass (residual) filter result therefore shows anomalous feature similar to HGM. In this study, ASA and HGM were found most suitable and appropriate in enhancing the trend/ pattern of distribution of radioelements and their total count. Hence, the enhancement and filtering techniques should not be limited to only potential field but to other non-potential, in particular, radiometric field data.
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