1.
論文(リポジトリ) 
Yang, J. ; Yamaguchi, Y. ; Yamada, H. ; Czyz, Z. H. ; Boerner, W. M. ; Mott, H. ; Luneburg, E. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
Characteristic polarization state theory is restudied for the symmetric coherent Sinclair scattering matrix case. First, the geometric relations of the characteristic polarization states on the Poincare sphere are derived. Based on
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these relations, simple formulas are given for all of the characteristic polarization states of this Sinclair matrix in Stokes vector form. From the formulation, it is clear that the COPOL Nulls are fundamental characteristic polarization states for the symmetric coherent Sinclair scattering matrix case, in that the others can straightforwardly be obtained from the Stokes vectors of the COPOL Nulls. For further study of the characteristic polarization state and the distribution of the received powers on the Poincare sphere, the authors introduce the concept of the equipower curve. It is defined as the curve on the Poincare sphere on which the received powers in some defined channel have the same value. They deal with the characteristics of the equipower curves for various special cases. In addition, they show how the characteristic polarization states are generated by the equipower curves. It is demonstrated that the characteristic polarization states can usually be regarded as the points of contact of the Poincare sphere and a conicoid representing a powerrelated quadratic form. This leads to a new method to introduce the characteristic polarization states
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2.
論文(リポジトリ) 
Yamaguchi, Y. ; Yajima, Y. ; Yamada, H. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
A fourcomponent decomposition scheme of the coherency matrix is presented here for the analysis of polarimetric synthetic aperture radar (SAR) images. The coherency matrix is used to deal with nonreflection symmetric scattering case,
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which is an extension of covariance matrix approach. The same decomposition results have been obtained. The advantage of this approach is explicit expressions of four scattering powers in terms of scattering matrix elements, which serve the interpretation of polarimetric SAR data quantitatively.
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3.
論文(リポジトリ) 
Yamaguchi, Y. ; Moriyama, T. ; Ishido, M. ; Yamada, H. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
A fourcomponent scattering model is proposed to decompose polarimetric synthetic aperture radar (SAR) images. The covariance matrix approach is used to deal with the nonreflection symmetric scattering case. This scheme includes and
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extends the threecomponent decomposition method introduced by Freeman and Durden dealing with the reflection symmetry condition that the copol and the crosspol correlations are close to zero. Helix scattering power is added as the fourth component to the threecomponent scattering model which describes surface, double bounce, and volume scattering. This helix scattering term is added to take account of the copol and the crosspol correlations which generally appear in complex urban area scattering and disappear for a natural distributed scatterer. This term is relevant for describing manmade targets in urban area scattering. In addition, asymmetric volume scattering covariance matrices are introduced in dependence of the relative backscattering magnitude between HH and VV. A modification of probability density function for a cloud of dipole scatterers yields asymmetric covariance matrices. An appropriate choice among the symmetric or asymmetric volume scattering covariance matrices allows us to make a best fit to the measured data. A fourcomponent decomposition algorithm is developed to deal with a general scattering case. The result of this decomposition is demonstrated with Lband PiSAR images taken over the city of Niigata, Japan.
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4.
論文(リポジトリ) 
Yang, J. ; Dong, G. ; Peng, Y. ; Yamaguchi, Y. ; Yamada, H. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
A generalized optimization of polarimetric contrast enhancement (GOPCE) is proposed in this letter. For this problem, it is not only necessary to find the optimal polarization states such that the received power ratio of a desired
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target and clutter is maximal, but also necessary to find three optimal coefficients such that the ratio of two factors associated with the desired target and clutter is maximal, where both the factors consist of three parameters, i.e., the Cloude entropy and two special similarity parameters. The optimal coefficients of the GOPCE are obtained by solving an eigenvalue problem. Using an example, we demonstrate that the GOPCE can be employed for detecting roads in a forest area by using polarimetric synthetic aperture radar data.
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5.
論文(リポジトリ) 
Yang, J. ; Peng, Y. N. ; Yamaguchi, Y. ; Yamada, H. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
For some special case, Huynen's decomposition cannot be used to extract a desired target from an average Kennaugh matrix. In this paper, the authors modify Huynen's method for overcoming its disadvantage, based on a simple
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transform of a Kennaugh matrix. Using an example, the effectiveness of the modified method is validated.
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6.
論文(リポジトリ) 
Yang, J. ; Yamaguchi, Y. ; Yamada, H. ; Boerner, W. M. ; Mott, H. ; Peng, Y. N. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
In a co or crosspolarized channel, the polarization states of the transmitting and receiving antennas are the same or orthogonal, and the corresponding target nulls (i.e., the copol nulls or xpol nulls) are defined as the polarization
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states of the transmitting antenna such that the received power equals zero. However, no systematic studies have been carried out to solve the problem of the corresponding target nulls if the polarization states of the transmitting and receiving antennas are independent. In this paper, the target null theory is extended to the case of two independent polarization states. For two arbitrary independent symmetric scattering matrices, it is proved that there exists only one pair of polarization states such that both of the received powers equal zero. This polarization states' pair is called the conull of the two targets, which can easily be obtained by solving an eigenvalue problem. Based on this concept and algebraic theory, the concept of the conull space is introduced for the symmetric scattering matrix case, and many important results are presented, e.g., the relations between the conull and the copol/xpol nulls, the properties of the conull space, and the relation between the conull and target decomposition. Finally, the conull for the asymmetric scattering matrix case is studied. The concepts of the monoconull space and the biconull space are introduced, and the relations between both spaces are presented
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7.
論文(リポジトリ) 
Yamaguchi, Y. ; Kimura, K. ; Kakizaki, S. ; Yamada, H. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
The ALOSPALSAR is the first Lband spaceborne SAR in the world equipped with a fully polarimetric data taking function. For the data utilization purpose, the authors have examined the polarimetric performance (scattering matrix and
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resultant images) over the Toyano area, Niigata City, Japan, using the airborne PiSAR radar. Since the resolution will be 20 m by 20 m on the ground surface by PALSAR, the PiSAR data (3 m by 3 m) are ensembled to be an equivalent size for ALOSPALSAR image simulation. The polarimetric characteristics of terrain including paddyfields, grassfields, residential areas, etc., were examined to show the difference in the rightleft polarization handedness basis and coherency vector, threecomponent scattering model, and polarimetric entropy.
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8.
論文(リポジトリ) 
Yamada, H. ; Yamaguchi, Y. ; Boerner, W. M. ; Yamada, Hiroyoshi ; Yamaguchi, Yoshio ; 山田, 寛喜 ; 山口, 芳雄
概要:
This paper present a new forest height feature extraction technique for single baseline polarimetric and interferometric SAR data. The authors have proposed polarimetric SAR interferometry based on the ESPRIT algorithm. However, the
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algorithm assumes that there exist dominant polarized components in both the ground and canopy. Hence, estimated interferometric phase of local scattering centers may be slightly biased when forest components are highly depolarized. In this report, we examine effect of depolarized components of forest in ESPRITbased polarimetric SAR interferometry. Numerical examples show that the effective scenario for the algorithm. Also, we present an alternative derivation o f t he E SPRI Ttype a lgorithm w hich h elps u s understand how the ESPRIT algorithm works for depolarized components. Experimental results by using ESAR data are also provided to show the performance of the ESPRIT estimation.
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9.
論文(リポジトリ) 
Yamada, H. ; Sato, K. ; Yamaguchi, Y. ; Boerner, W. M. ; Yamada, Hiroyoshi ; Yamaguchi, Yoshio ; 山田, 寛喜 ; 山口, 芳雄
概要:
Polarimetric SAR interferometry has been widely studied for forest observations. The technique utilizes polarization state difference among local scattering centers of the forest to decompose them. Using the method, we can estimate
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precise forest parameters. We proposed an alternative method based on the ESPRIT algorithm for the estimation. The method can detect as many as 3 local scatterers with fully polarimetric data, and can extract interferometric phase of each local scatterer. In this paper, we verify the availability of the method in 2 and 3localscatterer model for forest estimation, and show that forest analysis with 3localscatterer improve height estimation accuracy. SIRC/XSAR data were used for these verifications. In addition, experimental results of restricted dualpolarization data are also provided to show availability of the method.
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10.
論文(リポジトリ) 
Yamaguchi, Y. ; Kimura, K. ; Yamada, H. ; Uratsuka, S. ; Boerner, W. M. ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; 山口, 芳雄 ; 山田, 寛喜
概要:
Pacific Rim Campaign has been successfully carried out in 2000. The well known AIRSAR system by JPL flew over Niigata Area, Japan, on Oct. 2, 2000, which brought us the Lband fully polarimetric data set. On the other hand, PiSAR,
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developed by CRL and NASDA, Japan, simultaneously (2 hours in advance) flew the same path taking the same area data in the Lband. It became possible for us to carry out comparative analyses using the same area data. Since the resolution and incidence angle of each SAR are different, we examined the difference in the two POLSAR images using correlation coefficient in the RightLeft Circular (RL) polarization basis, polarimetric entropy, and three component scattering power ratio.
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