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Factorized Geometrical Autofocus On the geometry search

Jan Torgrimsson (Institutionen för rymd- och geovetenskap, Radarfjärranalys) ; Lars M. H. Ulander (Institutionen för rymd- och geovetenskap, Radarfjärranalys) ; P. Dammert ; H. Hellsten
IEEE Radar Conference (RadarConf), Philadelphia, PA, USA, May 02-06, 2016 (1097-5764). p. 293-297. (2016)
[Konferensbidrag, refereegranskat]

This paper deals with local geometry optimization within the scope of Factorized Geometrical Autofocus (FGA). The FGA algorithm is a Fast Factorized Back-Projection (FFBP) formulation with six free geometry parameters. These are tuned until a sharp image is obtained, i.e. with respect to an object function. To optimize the geometry (from a focus perspective) for a small image area, we propose an efficient routine based on correlation, sensitivity analysis and Broyden-Fletcher-Goldfarb-Shanno (BFGS) minimization. The new routine is evaluated using simulated Ultra-WideBand (UWB) data. By applying the FGA algorithm step-by-step, an erroneous geometry is compensated. This gives a focused image. In regard to run time, the new routine is approximately 100 times faster than a brute-force approach, i.e. for this FGA problem. For a general problem, the run time reduction will be far greater. To be more specific: with x parameters and N values to assess for each parameter; it is anticipated that the computational effort will decrease exponentially by a factor close to N-x.

Nyckelord: Autofocus, Back-Projection, FGA, SAR, UWB, SAR, Engineering, Electrical & Electronic, Telecommunications



Denna post skapades 2016-11-25.
CPL Pubid: 245630

 

Institutioner (Chalmers)

Institutionen för rymd- och geovetenskap, Radarfjärranalys

Ämnesområden

Geofysik

Chalmers infrastruktur