Comparison of Fractal Dimensions of SAR and Optical Digital Elevation Models

要旨

Digital Elevation Models produced using Radar and Optical image data pairs represent three dimensional complex, irregular shaped topographic surfaces. Since Euclidean Geometry is confined to regular shaped objects, Fractal Geometry is made use of to express the geometrical dimension of DEMs. In this study, Fractal Dimension is computed for Synthetic Aperture Radar (InSAR, SRTM) and Optical (Carto) DEMs by three different approaches viz., Differential Box Counting, Semi-Variogram and Wavelet Power Spectral method. Adequacy of each of the method to compute a single fractal dimension for entire DEM and performance of these methods for SAR and Optical DEM data sets is studied. In case of Variogram method, it is attempted to bring out additional clarity on the technique to identify the extent of linear segment of variogram in order to estimate slope, H and then fractal dimension. The methods are compared and the results are discussed.