University of Twente Student Theses


Evaluation of Optical Images Sub-Pixel Correlation for Estimating Ground Deformation

Yaseen, Muhammad (2009) Evaluation of Optical Images Sub-Pixel Correlation for Estimating Ground Deformation.

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Abstract:Sub-pixel correlation of optical images can give valuable information for terrain change monitoring and estimating ground deformation. The evaluation of a newly developed sub-pixel correlation technique (COSI-Corr) can give a better understanding of the process characterizing the change. The present study aims at evaluating its performance in terms of sensitivity, repeatability, robustness and applicability. The sub-pixel correlation of optical images bracketing an earthquake (2005 Kashmir earthquake) event, through their precise orthorectification and coregistration, was carried out with different datasets, DEM options and methodological parameters. The correlated images, their derived maps and graphs were compared and interpreted in order to evaluate the technique with respect to the above mention functionalities. After analyzing the correlated images, their derived maps and graphs, it was found that the technique may be applied for terrain change monitoring. It can assist in giving preliminary damages assessments as soon as pre- and post-event images are available. However, in estimating ground deformation such as displacement along a fault, the results after applying different datasets, DEM options and methodological parameters are varying and inconsistent. The Sinc 25 resampling method and Frequential correlator give comparatively accurate results while the Bilinear resampling method and Statistical correlator results were found to be relatively stable but less accurate. The third resampling method, Bicubic, did not provide accurate results and in most cases the results were unrealistic too. There is still need to go into deeper theoretical details of the methodology in order to understand the behaviour of change of different parameters and its effects on the results. For checking the repeatability and accuracy of displacement estimation, a flat area should be selected in order to minimize DEM inherent errors.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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