Assessment of L-band Sar Data at Different Polarization Combinations for Crop and Other Landuse Classification

In the present study evaluation of L-band SAR data at different polarization combinations in linear, circular as well as hybrid polarimetric imaging modes for crop and other landuse classifications has been carried out. Full-polarimetric radar data contains all the scattering information for any arbitrary polarization state, hence data of any combination of transmit and receive polarizations can be synthesized, mathematically from full-polarimetric data. Circular and various modes of hybrid polarimetric data (where the transmitter polarization is either circular or orientated at 45◦, called π/4 and the receivers are at horizontal and vertical polarizations with respect to the radar line of sight) were synthesized (simulated) from ALOSPALSAR fullpolarimetric data of 14th December 2008 over central state farm central latitude and longitude 29◦15′N/75◦43′E and bounds for northwest corner is 29◦24′N/75◦37′E and southeast corner is 29◦07′N/75◦48′E in Hisar, Haryana (India) Supervised classification was conducted for crops and few other landuse classes based on ground truth measurements using maximum-likelihood distance measures derived from the complex Wishart distribution of SAR data at various polarization combinations. It has been observed that linear fullpolarimetric data showed maximum classification accuracy (92%) followed by circular-full (89%) and circular-dual polarimetric data (87%), which was followed by hybrid polarimetric data (73–75%) and then linear dual polarimetric data (63–71%). Among the linear dual polarimetric data, co-polarization complex data showed better Received 11 July 2011, Accepted 2 November 2011, Scheduled 16 November 2011 * Corresponding author: Dipanwita Haldar ([email protected]).