Pixel and sub-pixel accuracy in satellite image georeferencing using an automatic contour matching approach

Abstract

This paper presents a technique for a fully automatic and operational geometric correction system capable of georeferencing satellite images with high accuracy. A simple Kepplerian orbital satellite model is considered and mean orbital elements are given as input from ephemeris data. To correct the systematic errors caused by these simplifications, nonzero value for the spacecraft's roll, pitch and yaw and failures in the satellite internal clock, an automatic global contour matching approach is proposed. It has three main steps: (i) Estimation of the gradient energy map (edges) and detection of the cloudless (reliable) areas; (ii) Initialization of the contours positions; (iii) Obtaining the transformation parameters (affine model) by means of a global contour optimization approach. Three different algorithms are proposed for optimization. The performance of the overall technique is assessed using AVHRR and multisensor AVHRR-SeaWiFS imagery.