Fitting polynomial statistics and reduction of speckle in one-look synthetic aperture radar echo signals

Speckle noise in high-resolution synthetic aperture radar (SAR) images is generated by the coherent processing of radar signals and exists in all types of coherent imaging systems. Speckle noise reduction is important for SAR imaging and its application. Traditional speckle noise reduction methods (filters) produce some mistakes in that the true target pixels are also eliminated for speckle pixels after imaging. It should be assessed by the target echo signals distribution whether the pixel is speckle before imaging. It is difficult to make statistics of the speckle without knowing the target reflective coefficient. Here, we fit the polynomial distribution function of target echo signals, and find that the relation among the polynomial coefficients can be regarded as the assessment criteria. In the meantime, we can correct the signals by the fitting polynomial, i.e. despeckling. The experimental results indicate that the fitting polynomial method is available for speckle statistics and speckle reduction in simulated SAR echo data