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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)
Nakamura, Jun ; Aoyama, Kazuyasu ; Ikarashi, Muneyuki ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi
出版情報: IEICE transactions on communications — IEICE transactions on communications.  E91-B  pp.2374-2379,  2008-07.  電子情報通信学会
本文リンク: http://hdl.handle.net/10191/23390
概要: This paper presents a coherent decomposition scheme for polarimetric SAR data. Coherent decomposition means the decomposition is applied to a single or a few scattering matrix data. Based on the scattering matrix acquired with an FM-CW polarimetric SAR system, we have devised a simple decomposition technique using the coherency matrix for the purpose of identifying scatterers. This paper presents the decomposition technique and some decomposition results obtained by a fully polarimetric FM-CW radar. It is shown the scattering mechanisms are well recovered and the orientation angles of wire scatterer are precisely measured. 続きを見る
6.

論文(リポジトリ)

論文(リポジトリ)
Suzuki, Junichiro ; Shoji, Yoshikazu ; Yamada, Hiroyoshi ; Yamaguchi, Yoshio ; Tanabe, Masahiro
出版情報: IEICE transactions on communications — IEICE transactions on communications.  E91-B  pp.1581-1588,  2008-05.  電子情報通信学会
本文リンク: http://hdl.handle.net/10191/23387
概要: The multistage Wiener filter (MWF) outperforms the full rank Wiener filter in low sample support environments. However, the MWF adaptive process should be stopped at an optimum stage to get the best performance. There are two methods to stop the MWF adaptive process. One method is to calculate until the final full-stage, and the second method is to terminate at r-stage less than full-stage. The computational load is smaller in the latter method, however, a performance degradation is caused by an additional or subtractive stage calculation. Therefore, it is very important for the r-stage calculation to stop an adaptive process at the optimum stage. In this paper, we propose a simple method based on a cross-correlation coefficient to stop the MWF adaptive process. Because its coefficient is calculated by the MWF forward recursion, the optimum stage is determined automatically and additional calculations are avoided. The performance was evaluated by simulation examples, demonstrating the superiority of the proposed method. 続きを見る
7.

論文(リポジトリ)

論文(リポジトリ)
Inomata, Kenji ; Hirai, Takashi ; Yamaguchi, Yoshio ; Yamada, Hiroyoshi
出版情報: IEICE transactions on communications — IEICE transactions on communications.  E91-B  pp.878-886,  2008-03.  電子情報通信学会
本文リンク: http://hdl.handle.net/10191/23389
概要: This paper presents a target location estimation method that can use a pair of leaky coaxial cables to determine the 2D coordinates of the target. Since convention location techniques using leaky coaxial cables can find a target location along the cable in 1D, they have been unable to locate it in 2D planes. The proposed method enables us to estimate target on a 2D plane using; 1) a beam-forming technique and 2) a reconstruction technique based on Hough transform. Leaky coaxial cables are equipped with numerous slots at regular interval, which can be utilized as antenna arrays that acts both as transmitters and receivers. By completely exploiting this specific characteristic of leaky coaxial cables, we carried out an antenna array analysis that performs in a beam-forming fashion. Simulation and experimental results support the effectiveness of the proposed target location method. 続きを見る
8.

論文(リポジトリ)

論文(リポジトリ)
Yamaguchi, Yoshio ; Yamamoto, Yukari ; Yamada, Hiroyoshi ; Yang, Jian ; Boerner, Wolfgang-Martin
出版情報: IEICE transactions on communications.  E91-B  pp.297-301,  2008-01.  The Institute of Electronics, Information and Communication Engineers
本文リンク: http://hdl.handle.net/10191/21333
概要: Classification of terrain is one of the most important applications of Polarimetric Synthetic Aperture Radar (POLSAR) image analysis. This paper presents a simple method to classify terrain by the use of the correlation coefficients in the circular polarization basis together with the total power of the scattering matrix in the X-band. The reflection symmetry condition that the co-polarized and the cross-polarized correlations are close to zero for natural distributed scatterers is utilized to extract characteristic parameters of small forests or cluster of trees, and oriented urban building blocks with respect to the direction of the radar illumination. Both of these kinds of scatterers are difficult to identify in high resolution POLSAR images of complex urban areas. The indices employed here are the correlation coefficient, a modified coefficient normalized by the reflection symmetric conditional case, and the total power. It is shown that forest areas and oriented building blocks are easily detected and identified. The terrain classification yielded by these combinations is very accurate as confirmed by photographic ground truth images. 続きを見る
9.

論文(リポジトリ)

論文(リポジトリ)
Yamada, Hiroyoshi ; Morishita, Masayuki ; Yamaguchi, Yoshio
出版情報: IEICE transactions on communications — IEICE transactions on communications.  E90-B  pp.2288-2296,  2007-09.  電子情報通信学会
本文リンク: http://hdl.handle.net/10191/23388
概要: High-resolution Direction-of-Arrival (DOA) estimation techniques for antenna arrays have been widely desired in many applications such as smart antennas, RF position location, and RFID system. To realize high-resolution capability of the techniques, precise array calibration is necessary. For an array of single-mode elements, a calibration matrix derived by the open-circuit method is the simplest one. Unfortunately, calibration performance of the method is not enough for the high-reslution DOA estimation techniques. In this paper, we consider problems of the calibration matrix derived by the method, and show that errors in the matrix can be effectively removed by an optimal diagonal weight coefficient. In the proposed compensation technique, the number of newly introduced parameters, or unknowns, is only one for an array of the identical elements. Performance of the simple compensation technique is verified numerically and experimentally. 続きを見る
10.

論文(リポジトリ)

論文(リポジトリ)
Endo, Natsumi ; Yamada, Hiroyoshi ; Yamaguchi, Yoshio
出版情報: IEICE transactions on communications — IEICE transactions on communications.  E90-B  pp.2297-2302,  2007-09.  電子情報通信学会
本文リンク: http://hdl.handle.net/10191/23386
概要: Direction of arrival estimation of coherent multipath waves by using superresolution technique often requires decorrelation preprocessings. Spatial smoothing preprocessings are the most popular schemes as the techniques. In mobile environment, position change of the target/transmitter often brings us decorrelation effect. In addition, multiple signals transmitted by an antenna array, such as a MIMO transmitter, can also cause the same effect. These effects can be categorized as the spatial smoothing preprocessing at the transmitter. In this paper, we analyze the spatial smoothing effect at the transmitter in the presence of multipath coherent waves. Theoretical and simulation results show that the spatial smoothing at the transmitter has a good feature in comparison with the conventional SSP at the receiving array. We also show that better decorrelation performance can be obtained when the SSPs at the transmitter and receiving array are applied simultaneously. 続きを見る