A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Advanced Technologies

Thesis (M. Eng.) - Asian Institute of Technology, 2000

Synthetic Aperture Radar (SAR) Interferometry is the technique for obtaining the Digital Elevation Model (DEM) of the Earth surface by processing the phase difference between coincidence SAR images. In this technique, coherence coefficient (CC) is the most important factor. This study is to investigate the effect of CC on the DEM of Mayon Volcano, Philippines derived from SAR interferometry technique. First, applying SAR interferometry, the DEM of Mayon Volcano is derived. Then, this DEM is compared to the referenced DEM derived from topographic map to investigate the relationship between DEM accuracy and CC value. Further, the land cover type categorized by Normalized Difference Vegetation Index (NDVI) is investigated with the changes of CC. The result show that the DEM accuracy decreases following the exponential function when CC increases. It is also concluded that for forest area, when NDVI increases, CC decreases following the negative-sloped line. This research proposes the method for detection of lava flow by combining CC and NDVI. From this study, the results can be used for the further researches either in application site or in technique site. It is recommended that it is necessary to validate DEM in any application and to improve phase unwrapping algorithm.