DEM Generation with SAR Interferometry Based on Weighted Wavelet Phase Unwrapping

Abstract

Synthetic aperture radar Interferometry (InSAR) is a significant 3D imaging technique to generate a Digital Elevation Model (DEM). The phase difference between the complex SAR images displays an interference fringe pattern from which the elevation of any point in the imaged terrain can be determined. Phase unwrapping is the most critical step in the signal processing of InSAR and especially in DEM generation. In this paper, a least squares weighted wavelet technique is used which overcomes the problem of slow convergence and the less-accurate Gauss-Seidel method. Here, by decomposing a grid to low-frequency and high-frequency components, the problem for a low-frequency component is solved. The technique is applied to ENVISAT ASAR images of Bam area. The experimental results compared with the Statistical-Cost Network Flow approach and the DEM generated from a 1/25000 scale map of the area shows the effectiveness of the proposed method.