Polarimetric calibration of SAR images using reflection symmetric targets with low helix scattering

• Published in: International journal of applied earth observation and geoinformation Vol. 104; p. 102559
• Main Authors: Chang, Yonglei, Zhao, Lingli, Shi, Lei, Nie, Yunju, Hui, Zhenyang, Xiong, Qiulin, Li, Pingxiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2021; Elsevier
• Subjects: Helix scattering; Polarimetric calibration; Reflection symmetry; SAR; Reflection symmetry; Helix scattering; SAR; Polarimetric calibration
• ISSN: 1569-8432; 1872-826X
• DOI: 10.1016/j.jag.2021.102559

•PolSAR image calibration with uniformly distributed targets.•Automatic extraction of reflection-symmetric targets.•Helix scattering component properties and distribution characteristics.•Tolerance of polarimetric feature to polarimetric distortion errors. Polarimetric synthetic aperture radar is an important technology for Earth observation. Generally, polarimetric calibration (PolCAL) should be performed before any quantitative applications. The reflection symmetric targets can relieve the dependence of PolCAL on calibrators. In this work, we use a helix-ratio feature to extract these targets. Through analysis, we find that the helix-ratio feature has a high tolerance to polarimetric distortions and is suitable for extracting samples in un-calibrated images for PolCAL. An adaptive segmentation algorithm is also developed to extract reflection symmetric targets automatically. Experiments with C- and X-band airborne images show that the extraction of reflection symmetric targets can improve the calibration accuracy of crosstalk. In addition, the proposed method can maintain the polarimetric signature of the targets in the calibration and can improve calibration performance when compared with other reflection symmetric target extraction methods.