Process to identify statistically homogeneous pixels in SAR images acquired in the same area

摘要

Process for identifying statistically homogeneous pixels in images acquired in the same area by means of a synthetic aperture radar, SAR sensor, comprising the following steps: (a) acquiring a plurality of N radar images (A1 ... AN) by means of a SAR sensor in the same area, (b) selecting a pixel and identifying it as a sample pixel (1), (c) defining an estimation window (10) so that the sample pixel identifies a set of pixels around of the sample pixel, said acquisition stage (a) formed with suitable acquisition geometries to consent the common data grid resampling and said step (b) formed after the common grid resampling, said process characterized by comprising after the stage (c) the following steps: (d) calculate a vector of N amplitude or intensity values relative to the sample pixel in the N available images and identify it as a sample vector , (e) calculate the vectors of N amplitude or intensity values for each pixel contained in the estimation window, similar to what has been done for the sample pixel, (f) compare, by means of a test of Kolmogorov-Smirnov, each vector of amplitude or intensity values of the pixels belonging to the estimation window with the sample vector to verify which of the vectors of amplitude or intensity values are generated by the same probability distribution function of the sample vector, (g) identify as homogeneous pixels (2, 3) to the sample pixel the pixels associated with the vectors of amplitude or intensity values that have passed the statistical test of stage (f) and identify as non-homogeneous pixels (4) to the sample pixel those pixels associated to the vectors of amplitude or intensity values that have not passed the test (f), (h) perform a connection test of the homogeneous pixels (2, 3) to the sample pixel, (i) eliminate the pixels contained in the estimation window (10) that, even if they are associated with vectors that have passed the test (f), are not yet connected (3) to the sample pixel, directly or by means of other pixels that were homogeneous to it, (j) identify as pixels statistically homogeneous the pixels that were homogeneous and connected to the sample pixel.