Linear structures´ detection on SAR multi-temporal sets using the Polar Transform

The Polar Transform (PT) is an efficient tool for detecting and linking the nearly aligned pixels. The method proposed in this paper uses this ability of the PT in order to extract the linear structures in the multi-temporal SAR images with strong speckle. Our algorithm consists in three steps: homomorphic channel summation, edge detection and linear structure extraction by PT. The homomorphic summation reduces data dimension and, meantime, filters the speckle. Since, in the sum image, the residual noise is additive, the edge detection, in the second step, is done by using Sobel´s detector, which is a low computation algorithm. The resulting binary image is transformed by using the PT. The linear structure is detected by looking for the maximum in the transformed image and, then, it is extracted by an inverse polar transformation. The reconstructed linear structure has the same position as in the multi-temporal images and its pixels are perfectly linked.