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) 
Lee, S. K. ; Hong, S. H. ; Kim, S. W. ; Yamaguchi, Y. ; Won, J. S. ; Yamaguchi, Yoshio ; 山口, 芳雄
概要:
The polarimetric features of an oyster farm in a coastal area are analyzed to verify the applicability of radar polarimetry and interferometry. Lband Airborne Synthetic Aperture Radar (AIRSAR) data and Japan Earth Resources
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Satellite (JERS1) data are used to examine the unique structure of an oyster farm located in South Korea. A specific feature of the oyster farm is the presence of numerous arrays of structures of various orientations that consist of exercisebarshaped poles protruding above sea level. This paper demonstrates that tide level is strongly correlated with the doublebounce scattering power from the vertical pole structures. This phenomenon is also verified by laboratory measurements using a network analyzer. In the laboratory experiment, doublebounce scattering and total power showed increasing trends with increased height of the vertical poles. Singlebounce scattering is sensitive to the orientation of horizontal poles relative to antenna orientation. HHpolarization is the most effective technique for imaging oyster farms from Lband polarimetric AIRSAR data. The authors were able to use a threecomponent decomposition of the AIRSAR data to distinguish an exposed tidal flat from a submerged tidal flat. The characteristics of the exposed tidal flat are similar to those of the carbon sponge in the laboratory test, except that the doublebounce scattering power is slightly greater in the realworld example. The singlebounce scattering component in AIRSAR data is generally greater than that in laboratory measurements because of seasurface conditions and oyster growth. When the horizontal pole was aligned normal to the radar look direction, singlebounce scattering was greater than the doublebounce scattering, even under watercovered conditions. While a difference in tide height of 10 cm contributed approximately 3.0 dB in the laboratory experiment, a difference in tide height of 20 cm contributed to only approximately 1.7 dB in the JERS1 SAR image intensity. JERS1 SAR image intensity for areas dominated by double and singlebounce scattering was 0.78 and 0.56, respectively. Results confirm that polarimetric SAR data are useful in selecting areas dominated by doublebounce scattering in oyster farms.
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6.
論文(リポジトリ) 
Yang, J. ; Yamaguchi, Y. ; Boerner, W. M. ; Lin, S. ; Yamaguchi, Yoshio ; 山口, 芳雄
概要:
This paper proposes two effective numerical methods to solve the optimal problem of contrast enhancement for the coherent and incoherent cases, respectively. For the coherent case, the objective function of the optimal problem is transformed
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into a bilinear form. Then a numerical method is presented by using the idea of the Sequential Unconstrained Minimization Technique (SUMT). For the incoherent case, a crossiterative method is proposed for solving the optimal problem of contrast enhancement, based on the formula of the optimal contrast polarization state in the matchedpolarized channel. Both the proposed methods are convergent and straightforward for programming. In addition, the proposed methods can be used for the bistatic radar case because in this paper, it is unnecessary to restrict the symmetry of the scattering matrix and the Kennaugh matrix. For showing the effectiveness of the proposed methods, the authors give three examples. The results of the calculation are completely identical with other papers', showing the validity of the proposed methods. In these three examples, if the receiving polarization state is independent of the transmitting's, the power ratios may be much larger than those in the cases of the copolarized, the crosspolarized, and the matchedpolarized channels, showing the importance of the considered models. In addition, the computation costs are estimated by these illustrative examples, illustrating that the proposed methods are very effective
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7.
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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8.
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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9.
論文(リポジトリ) 
Moriyama, T. ; Uratsuka, S. ; Umehara, T. ; Satake, M. ; Nadai, A. ; Maeno, H. ; Nakamura, K. ; Yamaguchi, Y. ; Yamaguchi, Yoshio ; 山口, 芳雄
概要:
This paper discusses the polarimetric correlation coefficient to extract the urban areas from polarimetric Synthetic Aperture Radar (POLSAR) image. For classification of POLSAR image, several methods have been proposed to extract
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polarimetric feature, such as Polarimetric EntropyAlpha, threecomponent scattering model, Huynen parameters and so on. However, there is a possibility that the polarimetric correlation coefficient has a potential for the objective of this paper, too. In order to verify the capability of polarimetric correlation coefficient, we examine the behavior of this coefficient between the urban areas and the natural distributed areas with respect to the several polarimetric scattering models and the difference of polarization basis. Moreover, we apply the polarimetric correlation coefficient to the actual polarimetric SAR data acquired by PiSAR/XSAR.
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10.
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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