A Novel Method for Layover Detection in Mountainous Areas with SAR Images

Lin Wu,Yuan Li,Hongxia Wang,Zhengwei Guo,Ning Li

doi:10.3390/rs13234882

Lin Wu, Yuan Li + Show 3 more

Open Access

https://doi.org/10.3390/rs13234882

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Abstract

It is well known that there are geometric distortions in synthetic aperture radar (SAR) images when the terrain undulates. Layover is the most common one, which brings challenges to the application of SAR remote sensing. This study proposes a novel detection method that is mainly aimed at the layover caused by mountains and can be performed with only medium-resolution SAR images and no other auxiliary data. The detection includes the following four stages: initial processing, difference image calculation and rough and fine layover detection. Initial processing mainly obtains the potential layover areas, which are mixed with the built-up areas after classification. Additionally, according to the analysis of the backscatter coefficient (BC) of various ground objects with different polarization images, the layover areas are detected step-by-step from the mixed areas, in which the region-based FCM segmentation algorithm and spatial relationship criteria are used. Taking the Danjiangkou Reservoir area as the study area, the relevant experiments with Sentinel-1A SAR images were conducted. The quantitative analysis of detection results adopted the figure of merit (FoM), and the highest accuracy was up to 87.6% of one selected validation region. Experiments in the South Taihang area also showed the satisfactory effect of layover detection, and the values of FoM were all above 85%. These results show that the proposed method can do well in the layover detection caused by mountains. Its simplicity and effectiveness are helpful in removing the influence of layover on SAR image applications to a certain extent and improving the development of SAR remote sensing technology.

Highlights

Introduction iationsAs a typical active microwave imaging sensor, synthetic aperture radar (SAR) has the abilities of all-day and all-weather observation [1]
A simple and effective method on layover detection, fitted to mountainous areas, was introduced. This method is mainly based on the backscatter coefficient (BC) analysis of the different ground objects and different polarization modes with time series SAR images
Due to the similarity of BC, layover would be classified in the built-up areas

Summary

Introduction

As a typical active microwave imaging sensor, synthetic aperture radar (SAR) has the abilities of all-day and all-weather observation [1]. It has been broadly applied in many fields, such as natural resources surveys, topographic mapping, ground object extraction and disaster monitoring [2]. Considering availability and universality, SAR images with medium resolution are still the most widely used images in large-scale remote sensing monitoring at present.

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Conclusion