Estimating the correlation properties of k-distributed SAR clutter

The authors extend previous analysis of the texture properties of k-distributed SAR clutter by including spatial correlation properties. Throughout they compare operating in the intensity domain with using its logarithm or square root (amplitude). Initially they derive the variance of the correlation coefficients in the three domains, assuming a negative exponential texture autocorrelation function (ACF), and demonstrate the advantage of both the log and amplitude domains over the intensity. In addition it is shown that a normalised estimator yields a further reduction in the variance. Finally, the results are combined in a derivation of the errors in the correlation length obtained by fitting the correlation coefficients to an assumed exponential autocorrelation function