Sea Spike Suppression Method Based on Optimum Polarization Ratio in Airborne SAR Images.

Yawei Zhao,Jinsong Chong,Kai Sun,Xue Yang,Yan Li

doi:10.3390/s21093269

Abstract

In the condition of ocean observation for high-resolution airborne synthetic aperture radar (SAR), sea spikes will cause serious interference to SAR image interpretation and marine target detection. In order to improve the ability of target detection, it is necessary to suppress sea spikes in SAR images. However, there is no report on sea spike suppression methods in SAR images. As a step forward, a sea spike suppression method based on optimum polarization ratio in airborne SAR images is proposed in this paper. This method is only applicable to the situation where VV and HH dual-polarized SAR data containing sea spikes are acquired at the same time. By calculating the optimum polarization ratio, this method further obtains the difference image of the panoramic area accomplishing sea spike suppression. This method is applied to a field airborne X-band SAR data, including ocean waves, oil spills and ships. The results show that the sea spikes are well suppressed, the contrast of ocean waves and the contrast of oil spills are improved, and the false alarm rate of ship detection is reduced. The discussions on these results demonstrate that the proposed method can effectively suppress sea spikes and improve the interpretability of SAR images.

Highlights

Synthetic aperture radar (SAR) is widely applied to the field of ocean remote sensing with obvious advantages of all-day, all-weather, high resolution and wide swath coverage.With the rapid development of airborne SAR technology, the resolution of airborne SAR images becomes higher every day
There is no report on sea spike suppression methods in SAR images
In order to solve this problem, a sea spike suppression method based on optimum polarization ratio in airborne SAR images is proposed in this paper, which is designated for the single-look complex (SLC) data of dual-polarized (VV and HH polarization) SAR

Summary

Introduction

Synthetic aperture radar (SAR) is widely applied to the field of ocean remote sensing with obvious advantages of all-day, all-weather, high resolution and wide swath coverage.With the rapid development of airborne SAR technology, the resolution of airborne SAR images becomes higher every day. Synthetic aperture radar (SAR) is widely applied to the field of ocean remote sensing with obvious advantages of all-day, all-weather, high resolution and wide swath coverage. High-resolution airborne SAR brings us more plentiful target details, but sea spikes are prone to appear when observing the ocean. It seriously affects SAR ocean image interpretation and marine target detection [1,2,3], which brings new challenges to the marine application of SAR images. From the experiments and numerical simulations, breaking waves have been suggested as the main contributor to sea spikes [5,6,7]. As the wind speed increases, the ocean wave height and rms slope will increase [8]

Methods

Results

Discussion

Conclusion