A radar reflectance model for terrain analysis using shape from shading

This paper describes work aimed at developing a practical shape-from-shading process for terrain analysis from radar imagery. The paper commences by providing an analysis of the radar reflectance properties of terrain structures. By using ground truth elevation data, we provide an empirical study of the radar reflectance characteristics for large-scale terrain features. The main conclusions of this study are twofold. Firstly, we show that radar has a strong backscatter component. Secondly, we show that the radar noise has a tail which extends to large reflectance values. Based on these observations we develop a semi-empirical shape-from-shading algorithm. We illustrate the effectiveness of the algorithm in extracting surface orientation information from radar images of a mountainous area of terrain in North Wales