基于地基合成孔径雷达的影像质量评价研究

Design of Rapid Quality Evaluation Index for Ground-Based Synthetic Aperture Radar Images

目前,地基合成孔径雷达变形监测技术在地质灾害、城市变化和农业生产等领域中的应用越来越广泛。由于环境因素和气候条件的变化,会使GB-SAR影像在采集过程中受到外界因素的干扰,从而影响数据的质量。而低质量的GB-SAR影像不仅会使得监测目标难以完整地显示,还会直接影响变形监测的精度,因此有效的影像质量评价方法对于确保变形监测工作和数据处理的准确性具有重要意义。本文基于Matlab平台,采用多阈值法筛选SAR影像高质量像元,并综合考虑每幅影像中的高质量像元的热信噪比、振幅离散指数、相位稳定性和相干系数,设计了一个评价SAR影像质量的综合指标,以验证本文方法的合理性。对比分析结果显示,本文所设计的综合质量指标能够显示GB-SAR影像质量随时间变化的趋势,并筛选出影像序列中的低质量数据,为后续的数据处理工作提供保障。

At present,the ground-based synthetic aperture radar(GB-SAR)deformation monitoring technology has been widely used in geological disasters,urban changes and agricultural production.Due to environmental factors and changes in climate conditions,GB-SAR images may be affected by external factors during the collection process,thereby affecting the quality of data.The low-quality GB-SAR image will not only make it difficult to display the monitoring target completely,but also directly affect the accuracy of deformation monitoring.Therefore,effective image quality evaluation methods are of great significance to ensure the accuracy of deformation monitoring work and data processing.This article is based on the Matlab platform and uses the multi-threshold method to filter high-quality pixels in SAR images.It comprehensively considers the thermal signalto-noise ratio,amplitude dispersion index,phase stability,and coherence coefficient of high-quality pixels in each image,and designs a comprehensive indicator to evaluate the quality of SAR images.Data are used to verify the rationality of the method proposed in this paper.The comparative analysis results show that the comprehensive quality index designed in this paper can show the trend of GB-SAR image quality over time,and screen out the low-quality data in the image sequence,providing guarantee for subsequent data processing.