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1.

論文(リポジトリ)

論文(リポジトリ)
Sato, Koichi ; Yamada, Hiroyoshi ; Yamaguchi, Yoshio
出版情報: IEICE transactions on electronics — IEICE transactions on electronics.  E84-C  pp.1829-1834,  2001-12.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/21347
概要: In this paper, we examine the polarimetric characteristics and the potential of the coherent decomposition in polarimetric synthetic aperture radar(SAR) interferometry. Coherent scattering decomposition based on the coherence optimization can separate effective phase center of different scattering mechanisms and can be used to generate canopy digital elevation model(DEM). This decomposition is applied to a simplified stochastic scattering model such as forest canopy. However, since the polarimetric characteristics are not well understood when the decomposition is carried out, we investigate its characteristics and potential using polarimetric entropy-alpha and three-component scattering matrix decomposition. The results show that the first and third components correspond to the lower and upper layer, respectively, in ideal case. In this investigation, SIR-C/X-SAR data of the Tien Shan flight-pass are used. 続きを見る
2.

論文(リポジトリ)

論文(リポジトリ)
Murase, Makoto ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi
出版情報: IEICE transactions on electronics — IEICE transactions on electronics.  E84-C  pp.1835-1840,  2001-12.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/21349
概要: Tree canopies contain various scattering elements such as leaves, branches and trunks, which contribute to complex back-scattering, depending on frequency and polarization. In this paper, we propose to use the polarimetric correlation coefficient for classifying trees, forests, and vegetations. The polarimetric correlation coefficient can be derived by the elements of Sinclair scattering matrix. Since the scattering matrix can be defined in any polarization basis, we examined the coefficient in the linear HV, circular LR, and optimum polarization bases. First, the change of correlation coefficient inside trees along the range direction is examined using small trees in a laboratory. The wider the range, the better the index. The coefficient defined in the LR polarization basis showed the largest change within tree canopy, which also contribute to retrieve scattering mechanism. Second, this index for discrimination is applied to polarimetric SAR data sets(San Francisco and Briatia area) acquired by AIRSAR and SIR-C/X-SAR. It is shown that polarimetric correlation coefficient in the LR basis best serves to distinguish tree types. 続きを見る
3.

論文(リポジトリ)

論文(リポジトリ)
Yamada, Hiroyoshi ; Yamaguchi, Yoshio ; Kim, Yunjin ; Rodriguez, Ernesto ; Boerner, Wolfgang-Martin
出版情報: IEICE transactions on electronics — IEICE transactions on electronics.  E84-C  pp.1917-1924,  2001-12.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/21351
概要: Synthetic aperture radar interferometry have been established in the past two decades, and used extensively for many applications including topographic mapping of terrain and surface deformation. Vegetation analysis is also a growing area of its application. In this paper, we propose an polarimetric SAR interferometry technique for interferometric phase extraction of each local scatterer. The estimated position of local scattering centers has an important information for effective tree height estimation of forest. The proposed method formulated for local scattering center extraction is based on the ESPRIT algorithm which is known for high-resolution capability of closely located incident waves. The method shows high-resolution performance when local scattered waves are uncorrelated and have different polarization characteristics. Using the method, the number of dominant local scattering centers and interferometric phases in each image pixel can be estimated directly. Validity of the algorithm is demonstrated by using examples derived from SIR-C data. 続きを見る
4.

論文(リポジトリ)

論文(リポジトリ)
Yamaguchi, Yoshio ; Ishido, Motoi ; Yamada, Hiroyoshi ; Moriyama, Toshifumi
出版情報: IEEE geoscience and remote sensing letters — IEEE geoscience and remote sensing letters.  3  pp.292-296,  2006-07.  IEEE
本文リンク: http://hdl.handle.net/10191/21403
概要: A four-component scattering model is proposed to decompose polarimetric synthetic aperture radar images. The covariance matrix approach is used to deal with the non-reflection symmetric scattering case. This scheme includes and extends the three-component decomposition method dealing with the reflection symmetry condition that the co-pol and the cross-pol correlations are close to zero. Circular polarization power is added as the fourth component to the three component scattering model which describes surface, double bounce, and volume scattering. This circular polarization term is added to take account of the co-pol and the cross-pol correlations which generally appear in complex urban area scatttering and disappear for natural distributed scatterer. 続きを見る
5.

論文(リポジトリ)

論文(リポジトリ)
Cui, Yi ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi ; Park, Sang-Eun
出版情報: IEEE transactions on geoscience and remote sensing — IEEE transactions on geoscience and remote sensing.  53  pp.1048-1060,  2015-02.  IEEE
本文リンク: http://hdl.handle.net/10191/31326
概要: In this paper, we address the theoretical aspects of coherence region modeling and its inversion methods for polarimetric interferometric SAR (PolInSAR). Instead of only considering the geometrical shape of the coherence region, we focus on directly modeling the whitened interferometric cross-correlation matrix of the PolInSAR data. In particular, we consider three classes of generic scattering models that respectively contain single, double and triple phase centers within one resolution cell. We then demonstrate, for each class, that the modeled whitened interferometric cross-correlation matrix is normal. Based on this property, we propose, for each case, efficient algorithms to obtain the best normal matrix approximation solution for model inversion from the observed whitened interferometric cross-correlation matrix. In addition, we show how a simple and effective criterion can be designed from the derived solutions for model validation. Finally, we verify the solutions with both simulated and real data. The results prove the proposed method to be a very promising tool for PolInSAR applications. 続きを見る
6.

論文(リポジトリ)

論文(リポジトリ)
Yamaguchi, Yoshio ; Sato, Akinobu ; Boerner, Wolfgang Mart ; Sato, Ryoichi ; Yamada, Hiroyoshi
出版情報: IEEE transactions on geoscience and remote sensing — IEEE transactions on geoscience and remote sensing.  49  pp.2251-2258,  2011-06.  IEEE
本文リンク: http://hdl.handle.net/10191/19302
概要: This paper presents an improvement to a decomposition scheme for accurate classification of polarimetric SAR images. Using a rotation of the coherency matrix to minimize the cross-polarized component, the four-component scattering power decomposition is applied to fully polarimetric SAR images. It is known that oriented urban area and vegetation signatures are decomposed into the same volume scattering mechanism in the previous decompositions and that it is difficult to distinguish vegetation from oblique urban areas with respect to radar direction of illumination within the volume scattering mechanism. It is desirable to distinguish these two scattering mechanisms for accurate classification although they exhibit similar polarimetric responses. The new decomposition scheme by implementing a rotation of coherency matrix first and subsequently the four-component decomposition yields considerably improved accurate results that oriented urban areas are recognized as double bounce objects from volume scattering. 続きを見る
7.

論文(リポジトリ)

論文(リポジトリ)
Yamada, Hiroyoshi ; Ozawa, Naoki ; Yamaguchi, Yoshio ; Hirano, Keizo ; Ito, Hiroyuki
出版情報: IEICE transactions on communications.  E96-B  pp.2469-2474,  2013-10.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/30817
概要: Ocean surface current radar is a Doppler radar to observe oceanographic information using the Bragg scattering resonance mechanism. In this paper, we consider angular resolution improvement of the radar. The radar employs an antenna array with FMICW operation, then it can resolve angular distribution by Digital Beam Forming (DBF) and distance by Fourier transform of the beat signal obtained by the FMICW radar. In order to obtain sufficient angular resolution, large array length or aperture with increasing the number of elements is needed, that is often difficult to realize in the HF/VHF ocean surface current radar. In this paper we propose to apply the Khatri-Rao (KR) product array processing to the radar. To verify effectiveness of the KR product array processing in angular resolution enhancement for the ocean surface current radar, we apply the KR product array to actual experimental data set of the radar, and show that the method is available to angular resolution enhancement and Doppler spectrum improvement. 続きを見る
8.

論文(リポジトリ)

論文(リポジトリ)
Shirai, Satoshi ; Yamada, Hiroyoshi ; Yamaguchi, Yoshio
出版情報: IEICE transactions on communications.  E96-B  pp.2475-2482,  2013-10.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/30818
概要: In this paper, we study on direction-of-arrival (DOA) estimation error reduction by Khatri-Rao (KR) product extended array in the presence of correlated waves. Recently, a simple array signal processing technique called KR product extended array has been proposed. By using the technique, degrees-of-freedom of an array can be easily increased. However, DOA estimation accuracy deteriorates when correlated or coherent waves arrive. Such highly correlated waves often arrive for radar application, hence error reduction technique has been desired. Therefore, in this paper, we propose a new method for error reduction preprocessing scheme by using N-th root of matrix. The N-th root of matrix has a similar effect to the spatial smoothing preprocessing for highly correlated signals. As a result, DOA estimation error due to signal correlation will be reduced. The optimal order of N depends on the data itself. In this paper, a simple iterative method to obtain adaptive N is also proposed. Computer simulation results are provided to show performance of the proposed method. 続きを見る
9.

論文(リポジトリ)

論文(リポジトリ)
Cheng, Tzu-Yu ; Yamaguchi, Yoshio ; Chen, Kun-Shan ; Lee, Jong-Sen ; Cui, Yi
出版情報: IEICE transactions on communications.  E96-B  pp.2573-2579,  2013-10.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/29710
概要: In this paper, a multi-temporal analysis of polarimetric synthetic aperture radar (Pol-SAR) data over the sandbank and oyster farm area is presented. Specifically, a four-component scattering model, being able to identify single bounce, double bounce, volume, and helix scattering power contributions, has been employed to retrieve information. Decomposition results of a time series RADARSAT Pol-SAR images acquired over the western Taiwan coast indicate that the coastal tide level plays a key role in the sandbank and oyster farm monitoring. At high tide levels, the underlying sandbank creates a shallow area with an increased roughness of the above sea surface, leading to an enhanced surface scattering power as compared to the ambient water. Contrarily, at low tide levels, the exposed sandbank appears to be a smooth scatterer, generating decreased backscattering power than the surrounding area. On the other hand, the double-bounce scattering power is shown to be highly correlated with the tide level in the oyster farms due to their vertical structures. This also demonstrates a promising potential of the four-component scattering power decomposition for coastal tide level monitoring applications. 続きを見る
10.

論文(リポジトリ)

論文(リポジトリ)
Yamada, Hiroyoshi ; Sakai, Hiroshi ; Yamaguchi, Yoshio
出版情報: IEICE transactions on communications — IEICE transactions on communications.  E94-B  pp.1201-1206,  2011-06.  電子情報通信学会
本文リンク: http://hdl.handle.net/10191/23385
概要: High resolution direction-of-arrival (DOA) estimation algorithm for array antennas becomes popular in these days. However, there are several error factors such as mutual coupling among the elements in actual array. Hence array calibration is indispensable to realize intrinsic performance of the algorithm. In the many applications, it is preferable that the calibration can be done in the practical environment in operation. In such a case, the incident wave becomes coherent multipath wave. Calibration of array in the multipath environment is a hard problem, even when DOA of elementary waves is known. To realize array calibration in the multipath environment will be useful for some applications even if reference signals are required. In this report, we consider property of reference waves in the multipath environment and derive a new calibration technique by using the multipath coherent reference waves. The reference wave depends on not only the DOA but also complex amplitude of each elementary wave. However, the proposed technique depends on the DOA only. This is the main advantage of the technique. Simulation results confirm the effectiveness of the proposed technique. 続きを見る