Improved multilook techniques applied to SAR and SCANSAR imagery

Multilook processing is commonly used in SAR image formation in order to reduce the speckle noise. We propose two new mutlilook techniques for improving the radiometric resolution without altering the geometric resolution and characteristics of the impulse response. These techniques are based on the formation of looks with different bandwidths. The final image is formed by giving each look a proper size and weighting and by adding them incoherently. The looks with wide bandwidth contribute to an improvement of the overall geometric resolution, while the looks with narrow bandwidth improve the overall radiometric resolution. The equivalent number of looks is more than 2.3 times the number of independent looks and is superior to conventional multilook processing with overlapping. Finally, using the proposed techniques, we present an algorithm for efficient SAR and ScanSAR processing and prove its validity by image comparison and analysis.