A Survey on SAR image Georegistration and Orthorectification

A Survey on SAR image Georegistration and Orthorectification Authors Nagashree. R.N, Vibha Rao 1Asst.Prof, Telecommunication Engineering, GSSSIETW, Mysuru, 2Asst.Prof, Electronics & Communication Engineering, NIEIT, Mysuru, [email protected], [email protected] ABSTRACT: This paper outlines the principle of Synthetic Aperture Radar (SAR). Also In this paper we have discussed what the factors are that results in SAR image distortion. A brief introduction to Geo Registration and Ortho rectification can be seen here. The distortion resulted in SAR image can be corrected by Geo Registration. Registration algorithms compute transformations to set correspondence between the two images. Hence a Registration process is a aligning of two images into a common coordinate system and then aligning them in order to monitor subtle changes between the two. But not all the distortion can be removed that includes distortions brought by elevation and it is very difficult to correct in Geo Registration method. Hence we go for Orthorectification which removes the perspective and terrain relief in the image for the purpose of creating a planimetrically correct image. This paper discusses about the problems occurring in SAR radar. Keyword: Digital Elevation Model (DEM), Ground Control points (GCP), Synthetic Aperture Radar (SAR), Referenced image, Sensed Image.