Unsupervised change detection on synthetic aperture radar images with generalized gamma distribution

The availability of synthetic aperture radar (SAR) data with high spatial resolution offers great potential for environmental monitoring due to the insensitivity of SAR to atmospheric and sunlight-illumination conditions. In this paper, an unsupervised change detection method for SAR images at medium to high resolution is proposed. The image ratioing approach is adopted, and a Bayesian unsupervised minimum-error thresholding algorithm is extended by proposing a technique based on Generalized Gamma distributions (GΓD). GΓD was recently found to be an accurate model for the statistics of SAR amplitudes at moderate to high resolution. Here, a specific parametric modeling approach for the ratio of G D-distributed SAR images is proposed and endowed with a probability density function estimation algorithm based on the method of log-cumulants. Consistency of this estimator is proven. Experimental results confirm the accuracy of the method for medium and high resolutions X-band SAR images.