Estimation and analysis of lacunarity of scattering signals at different incident angles

The sea surface has the fractal nature. For normal incidence, some methods have been developed for extracting fractal parameters from the electromagnetic (EM) scattered signals. When the EM waves of different incident angles are scattered by the fractal sea surface, the scattered signal recorded at observation point will show many different properties, which will affect the accuracy of estimation of fractal parameters. In this paper, based on the method of skeleton of wavelet transform modulus maxima (WTMM), we analyze the hierarchical structures of the EM scattered signals at different incident angles to estimate the lacunarity of the fractal surface. It is shown that the optimal incident angle is between the sea surface and incident pulse passing through the mirror position of observation point and the midpoint of one-dimensional sea surface, approximately. The results of simulation are found interestingly successful to use the estimated parameters in remote sensing applications.