scholarly journals Comparative Analysis of Polarimetric SAR Calibration Methods

2018 ◽  
Vol 10 (12) ◽  
pp. 2060 ◽  
Author(s):  
Yoon Jung ◽  
Sang-Eun Park
Keyword(s):  
Comparative Analysis ◽  
Calibration Method ◽  
System Model ◽  
Synthetic Aperture ◽  
Polarimetric Sar ◽  
Alos Palsar ◽  
Polarimetric Synthetic Aperture Radar ◽  
System Parameters ◽  
Calibration Methods ◽  
Polarimetric Calibration

In the diverse applications of polarimetric Synthetic Aperture Radar (SAR) systems, it is a crucial to conduct polarimetric calibration, which aims to remove the radar system distortion effects prior to utilizing polarimetric SAR observations. The objective of this study is to evaluate the performance of different polarimetric calibration methods. Two widely used methods, the Van Zyl and Quegan methods, and one recently proposed method, such as the Villa method, have been selected among various calibration methods in literature. The selected methods have basic differences in their assumptions that are applied to the polarimetric system model. In order to evaluate the calibration performances under different system parameters and ground characteristics, comparative analysis of the calibration results were conducted on synthetic polarimetric SAR data and ALOS PALSAR quad-pol mode data. Based on the experimental results, the advantages and limitations of different methods were clarified, and a simple hybrid calibration method is presented to further improve the polarimetric calibration performance.

scholarly journals Modified Hybrid Freeman/Eigenvalue Decomposition for Polarimetric SAR Data

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shuang Zhang ◽  
Shuang Wang ◽  
Bo Chen
Keyword(s):  
Synthetic Aperture Radar ◽  
San Francisco ◽  
Decomposition Method ◽  
Unitary Transformation ◽  
Synthetic Aperture ◽  
Eigenvalue Decomposition ◽  
Reflection Symmetry ◽  
Polarimetric Sar ◽  
Polarimetric Synthetic Aperture Radar ◽  
Airborne Sensors

Because of the rapid advancement of the airborne sensors and spaceborne sensors, large volumes of fully polarimetric synthetic aperture radar (PolSAR) data are available, but they are too complex to interpret difficultly. In this paper, a modified hybrid Freeman/eigenvalue decomposition method for the coherency matrix derived from the fully PolSAR sensors is proposed. The proposed modified hybrid Freeman/eigenvalue decomposition uses a real unitary transformation on the coherency matrix to release correlations between the copolarized term and cross polarized term, and the scattering models are derived from eigenvectors of the coherency matrix with reflection symmetry condition. The anisotropy and entropy are used to determine whether the volume scattering component is derived from the man-made structures or not. Moreover, the scattering powers from the proposed hybrid Freeman/eigenvalue decomposition are all nonnegative values. Fully PolSAR data on San Francisco acquired by AIRSAR sensor are used in the experiments to prove the efficacy of the proposed decomposition.

scholarly journals ANALYSIS OF SCATTERING COMPONENTS FROM FULLY POLARIMETRIC SAR IMAGES FOR IMPROVING ACCURACIES OF URBAN DENSITY ESTIMATION

2016 ◽  
Vol III-7 ◽  
pp. 219-226
Author(s):  
J. Susaki
Keyword(s):  
Normal Distribution ◽  
Urban Areas ◽  
Synthetic Aperture ◽  
Sar Image ◽  
Polarimetric Sar ◽  
Sar Images ◽  
Polarimetric Synthetic Aperture Radar ◽  
Urban Density ◽  
Concrete Blocks ◽  
Image Pixels

In this paper, we analyze probability density functions (PDFs) of scatterings derived from fully polarimetric synthetic aperture radar (SAR) images for improving the accuracies of estimated urban density. We have reported a method for estimating urban density that uses an index <i>T</i><sub><i>v</i>+<i>c</i></sub> obtained by normalizing the sum of volume and helix scatterings <i>P</i><sub><i>v</i>+<i>c</i></sub>. Validation results showed that estimated urban densities have a high correlation with building-to-land ratios (Kajimoto and Susaki, 2013b; Susaki et al., 2014). While the method is found to be effective for estimating urban density, it is not clear why <i>T</i><sub><i>v</i>+<i>c</i></sub> is more effective than indices derived from other scatterings, such as surface or double-bounce scatterings, observed in urban areas. In this research, we focus on PDFs of scatterings derived from fully polarimetric SAR images in terms of scattering normalization. First, we introduce a theoretical PDF that assumes that image pixels have scatterers showing random backscattering. We then generate PDFs of scatterings derived from observations of concrete blocks with different orientation angles, and from a satellite-based fully polarimetric SAR image. The analysis of the PDFs and the derived statistics reveals that the curves of the PDFs of <i>P</i><sub><i>v</i>+<i>c</i></sub> are the most similar to the normal distribution among all the scatterings derived from fully polarimetric SAR images. It was found that <i>T</i><sub><i>v</i>+<i>c</i></sub> works most effectively because of its similarity to the normal distribution.

scholarly journals HETEROGENEITY MEASUREMENT BASED ON DISTANCE MEASURE FOR POLARIMETRIC SAR DATA

2018 ◽  
Vol IV-3 ◽  
pp. 233-237
Author(s):  
Xiaoli Xing ◽  
Qihao Chen ◽  
Xiuguo Liu
Keyword(s):  
Standard Deviation ◽  
Synthetic Aperture Radar ◽  
Covariance Matrix ◽  
Distance Measure ◽  
Synthetic Aperture ◽  
Polarimetric Sar ◽  
Polarimetric Synthetic Aperture Radar ◽  
Local Window ◽  
The Mean ◽  
Sar Data

To effectively test the scene heterogeneity for polarimetric synthetic aperture radar (PolSAR) data, in this paper, the distance measure is introduced by utilizing the similarity between the sample and pixels. Moreover, given the influence of the distribution and modeling texture, the K distance measure is deduced according to the Wishart distance measure. Specifically, the average of the pixels in the local window replaces the class center coherency or covariance matrix. The Wishart and K distance measure are calculated between the average matrix and the pixels. Then, the ratio of the standard deviation to the mean is established for the Wishart and K distance measure, and the two features are defined and applied to reflect the complexity of the scene. The proposed heterogeneity measure is proceeded by integrating the two features using the Pauli basis. The experiments conducted on the single–look and multilook PolSAR data demonstrate the effectiveness of the proposed method for the detection of the scene heterogeneity.

scholarly journals Polarimetric Calibration of the GaoFen-3 Mission Using Active Radar Calibrators and the Applicable Conditions of System Model for Radar Polarimeters

2019 ◽  
Vol 11 (2) ◽  
pp. 176 ◽  
Author(s):  
Weibin Liang ◽  
Zengzeng Jia ◽  
Xiaolan Qiu ◽  
Jun Hong ◽  
Qingjun Zhang ◽  
...  
Keyword(s):  
Data Processing ◽  
Detailed Analysis ◽  
System Model ◽  
Processing Algorithm ◽  
Calibration Data ◽  
Polarimetric Sar ◽  
Classic Model ◽  
Data Processing Algorithm ◽  
Improved Model ◽  
Polarimetric Calibration

GaoFen-3, the first polarimetric SAR satellite of China, carried out polarimetric calibration experiments using C-band polarimetric active radar calibrators (PARCs), trihedral corner reflectors (TCRs), and dihedral corner reflectors (DCRs). The calibration data were firstly processed referring to the classic 2 × 2 receive R and transmit T model for radar polarimeter systems, first proposed by Zebker, Zyl, and Held, and Freeman’s method based on PARCs, but the results were not good enough. After detailed analysis about the GaoFen-3 polarimetric system, we found that the system had some nonlinearity, then a new imbalance parameter was introduced to the classic model, which is equivalent to the γ proposed in Freeman’s paper about a general polarimetric system model. Then, we proposed the calibration data processing algorithm for GaoFen-3 based on the improved model and obtained better results. The algorithm proposed here is verified to be suitable for GaoFen-3 and can be applied to other spaceborne and airborne fully-polarimetric SAR systems.

scholarly journals ANALYSIS OF SCATTERING COMPONENTS FROM FULLY POLARIMETRIC SAR IMAGES FOR IMPROVING ACCURACIES OF URBAN DENSITY ESTIMATION

2016 ◽  
Vol III-7 ◽  
pp. 219-226
Author(s):  
J. Susaki
Keyword(s):  
Normal Distribution ◽  
Urban Areas ◽  
Synthetic Aperture ◽  
Sar Image ◽  
Polarimetric Sar ◽  
Sar Images ◽  
Polarimetric Synthetic Aperture Radar ◽  
Urban Density ◽  
Concrete Blocks ◽  
Image Pixels

In this paper, we analyze probability density functions (PDFs) of scatterings derived from fully polarimetric synthetic aperture radar (SAR) images for improving the accuracies of estimated urban density. We have reported a method for estimating urban density that uses an index &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;&lt;i&gt;v&lt;/i&gt;+&lt;i&gt;c&lt;/i&gt;&lt;/sub&gt; obtained by normalizing the sum of volume and helix scatterings &lt;i&gt;P&lt;/i&gt;&lt;sub&gt;&lt;i&gt;v&lt;/i&gt;+&lt;i&gt;c&lt;/i&gt;&lt;/sub&gt;. Validation results showed that estimated urban densities have a high correlation with building-to-land ratios (Kajimoto and Susaki, 2013b; Susaki et al., 2014). While the method is found to be effective for estimating urban density, it is not clear why &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;&lt;i&gt;v&lt;/i&gt;+&lt;i&gt;c&lt;/i&gt;&lt;/sub&gt; is more effective than indices derived from other scatterings, such as surface or double-bounce scatterings, observed in urban areas. In this research, we focus on PDFs of scatterings derived from fully polarimetric SAR images in terms of scattering normalization. First, we introduce a theoretical PDF that assumes that image pixels have scatterers showing random backscattering. We then generate PDFs of scatterings derived from observations of concrete blocks with different orientation angles, and from a satellite-based fully polarimetric SAR image. The analysis of the PDFs and the derived statistics reveals that the curves of the PDFs of &lt;i&gt;P&lt;/i&gt;&lt;sub&gt;&lt;i&gt;v&lt;/i&gt;+&lt;i&gt;c&lt;/i&gt;&lt;/sub&gt; are the most similar to the normal distribution among all the scatterings derived from fully polarimetric SAR images. It was found that &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;&lt;i&gt;v&lt;/i&gt;+&lt;i&gt;c&lt;/i&gt;&lt;/sub&gt; works most effectively because of its similarity to the normal distribution.

scholarly journals Remote Sensing of Ocean Waves by Polarimetric SAR

2006 ◽  
Vol 23 (12) ◽  
pp. 1768-1773 ◽  
Author(s):  
Yijun He ◽  
Hui Shen ◽  
William Perrie
Keyword(s):  
Synthetic Aperture Radar ◽  
Ocean Waves ◽  
Synthetic Aperture ◽  
Modulation Transfer ◽  
Wave Direction ◽  
Polarimetric Sar ◽  
Polarimetric Synthetic Aperture Radar ◽  
Wave Slope ◽  
Hydrodynamic Modulation ◽  
Aperture Radar

Abstract A new method to measure ocean wave slope spectra using fully polarimetric synthetic aperture radar (POLSAR) data was developed without the need for a complex hydrodynamic modulation transform function. There is no explicit use of a hydrodynamic modulation transfer function. This function is not clearly known and is based on hydrodynamic assumptions. The method is different from those developed by Schuler and colleagues or Pottier but complements their methods. The results estimated from NASA Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) C-band polarimetric SAR data show that the ocean wavelength, wave direction, and significant wave height are in agreement with buoy measurements. The proposed method can be employed by future satellite missions such as RADARSAT-2.

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