RETRIEVAL OF OCEAN WAVELENGTH AND WAVE DIRECTION FROM SAR IMAGE BASED ON RADON TRANSFORM

摘要

The method for retrieving the ocean wave spectrum from the Synthetic Aperture Radar (SAR) imagery is currently the most widely used for calculation of the wave high, wavelength and wave direction. However the most current of methods are relatively complicated. This paper presents an algorithm which is based on Radon transform In this algorithm, firstly, with the property of Radon transform that the line in the SAR image and the point in the transformed space are one-to-one correspondence, the texture feature of the wave in SAR image is detected to calculate the wavelength and probable wave direction. Secondly, according to the theory of the ocean wave and the trends of the wavelength in two close sub-images, the actual wave direction is determined eventually. This article selects an ERS - 2 SAR image around Taiwan as the study area. The results of calculation are compared with the results obtained by Two-Dimensional Fast Fourier Transform (2D- FFT). The study results demonstrate that the use of the Radon transform is available without loss of the accuracy when retrieving the wave wavelength and wave direction from the ERS-2 SAR images.