CIRFA welcomes you to a seminar presented by CIRFA PhD student Cornelius Quigley and Researcher Anca Cristea.
Date/time: 7. February 2019, 14:00 — 15:00
Venue: CIRFA, SIVA Innovation Centre (Forskningsparken),
The title of Cornelius presentation is: “Retrieval of the dielectric properties of oil slick using SAR via a polarimetric two-scale model”
A two scale model is employed in order to invert for the permittivity of oil slick using SAR. The model is an extension to the X-Bragg model in that it models the ocean surface as being composed of a collection of randomly orientated, slightly roughed titled facets. Initial results suggest that the model is capable of estimating, with a high degree of accuracy, realistic values for the dielectric constant.
Anca will follow with a presentation titled: ” Incidence angle dependencies in polarimetric SAR images “.
The incidence angle effect manifests itself in SAR images as a decay of the average intensities from near range to far range. The decay constitutes a nuisance for both human observers and automatic image analysis algorithms such as segmentation, particularly because it varies with polarization and surface roughness. We propose a simple statistical model that incorporates the surface-specific intensity decays for use in a fully automatic and unsupervised segmentation algorithm based on Gaussian mixtures. As the model accurately represents the intensity statistics throughout the entire image, the segmentation result does no longer show banding artefacts along the range dimension. In addition, new features are extracted. It is generally assumed that the effect is not a major concern for narrow swath quad-polarimetric scenes, due to the fact that they cover small incidence angle ranges (2-3º). An analysis of Fine Quad-Pol and Wide Fine Quad-Pol RADARSAT-2 scenes representing open water, sea ice and oil slicks shows that the incidence angle effect can however be significant for segmentation even at ranges as small as 2º, for a particular number of looks.’