Principal Investigators: Akira Ishimaru, Yasuo Kuga and Chi H. Chan
Sponsor: National Science Foundation
Abstract: Many natural and man-made media vary randomly in space and time and are called "random media." Examples are atmospheric and ocean turbulence, particulate matter, rain, fog, snow, terrain, vegetation, biological media, composite materials, and disordered media. Optical and acoustic waves and microwaves propagating through these random media experience random fluctuations, and these interactions between the wave and the random medium affect a broad range of practical problems such as communications, remote sensing of media; and detection, identification and imaging of objects in media. Our work addresses these problems with the aim of advancing knowledge and developing theoretical models. We stress the development of multiple scattering theories as applied to generalized space-time interferometry and imaging in random media. This includes the time-frequency correlation for pulse, spatial interference for angular and polarization correlations, and coherent interference for backscattering enhancement.
References:
A. Ishimaru, "Electromagnetic Wave Propagation, Radiation, and Scattering", 637 pages. New Jersey: Prentice Hall, 1991.
A. Ishimaru, "Backscattering Enhancement: From Radar Cross Sections to Electron and Light Localizations to Rough Surface Scattering," IEEE Antennas and Propagation Magazine, 33:5, October 1991, pp. 7-11, (Invited Paper).
A. Ishimaru, C. T. C. Le, Y. Kuga, L. Ailes-Sengers, and T.-K. Chan, "Polarimetric scattering theory for high slope rough surfaces," Progress in Electromagnetics Research, M. Tateiba and L. Tsang, editors, EMW Publishing, Cambridge, MA, 1996, pp. 1-36.
Y. Kuga, C. T. C. Le, A. Ishimaru, and L. Ailes-Sengers, "Analytical, experimental, and numerical studies of angular memory signatures of waves scattered from one-dimensional rough surfaces," IEEE Transactions on Geoscience and Remote Sensing, 34:6, November 1996, pp. 1300-1307.
http://www.ee.washington.edu/research/ersl/
Principal Investigator: Akira Ishimaru, Yasuo Kuga, and Chi H. Chan
Sponsor: National Science Foundation
Abstract: This REU grant is intended to supplement the NSF award "Multiple Scattering, Space-Time Interferometry and Imaging in Random Media" for undergraduate students conducting research projects in this area.
http://www.ee.washington.edu/research/ersl/
Principal Investigator: Akira Ishimaru and Yasuo Kuga
Sponsor: Army Research Office
Abstract: For the past few years, we have been conducting fundamental research on millimeter and optical wave propogation and scattering as applicable to geophysical media, such as, hydrometeors, fog, smoke, ice, snow, vegetation, and terrain. Specifically, we propose to conduct theoretical and experimental studies of enhanced backscattering from two-dimensional very rough surfaces, optical experiments on the Mueller matrix for rough surfaces and discrete scatterers, and polarimetric microwave and millimeter wave experiments on dense media and rough surfaces. We will also conduct studies of radiative transfer and pulse scattering and enhanced backscattering from dense media and strong resonant localizations. Experimental work and numerical Monte-Carlo calculations will be conducted to guide the development of theoretical models. These basic studies are essential in understanding the physical mechanisms of wave scattering in the geophysical environment and their effects on communications, polarimetric radars, lidars, and target identification and resolution in the geophysical environment.
References:
A. Ishimaru, Wave Propagation and Scattering in Random Media, Volume I: Single Scattering and Transport theory; Volume II: Multiple Scattering, Turbulence, Rough Surfaces and Remote Sensing, 572 pages. New York: Academic Press, 1978. (Translated into Russian, 1981 and Chinese, 1986.) Reissued as an IEEE Press-Oxford University Press Classic Reissue, 1997.
P. Phu, A. Ishimaru, and Y. Kuga, "Controlled Millimeter-Wave Experiments and Numerical Simulations on the Enhanced Backscattering from One-Dimensional Very Rough Surfaces," Radio Science, 28:4, July-August 1993, pp. 533-548.
V. I. Tatarskii, A. Ishimaru, and V. U. Zavorotny, editors, Wave Propagation in Random Media (Scintillation), 487 pages, SPIE Press, Bellingham, WA and Institute of Physics Publishing, Bristol, England, 1993.
http://www.ee.washington.edu/research/ersl/
Principal Investigator: Akira Ishimaru and Yasuo Kuga
Sponsor: Army Research Office
Abstract: This grant entitled, "Wideband Pulse Scattering from Rough Surfaces," is to augment the parent grant on "Wave Propagation and Scattering in Geophysical Media" by supporting one or two additional graduate students. The research is centered on the problem of ultra-shortpulse scattering by rough surfaces which is important in remote sensing of terrain and in the discrimination of targets against clutter at grazing angles.
References:
A. Ishimaru, L. Ailes-Sengers, P. Phu, and D. Winebrenner, "Pulse Broadening and Two-Frequency Mutual Coherence Function of the Scattered Wave from Rough Surfaces," Waves in Random Media, 4:2, April 1994, pp. 139-148.
A. Ishimaru, L. Ailes-Sengers, P. Phu, and D. Winebrenner, "Broadening of Enhanced Backscattering from Rough Surfaces," Waves in Random Media, 4:4, October 1994, pp. 453-465.
A. Ishimaru, L. Ailes-Sengers, P. Phu, and D. Winebrenner, "Pulse Scattering by Rough Surfaces," chapter in Ultra-Wideband, Short-Pulse Electromagnetics 2, edited by H. L. Bertoni, L. Carin, L. B. Felsen, and S. U. Pillai, Plenum Publishing, 1995.
T.-K. Chan, Y, Kuga, and A. Ishimaru, "Angular memory effect of millimeter-wave scattering from two-dimensional conducting random rough surfaces," Radio Science, 31:5, September-October 1996, pp. 1067-1076.
http://www.ee.washington.edu/research/ersl/
Principal Investigators: Akira Ishimaru and Yasuo Kuga
Sponsor: Office of Naval Research
Abstract: Many geophysical media such as the ocean medium, ocean surfaces and bottom, terrain, and the atmosphere are inhomogeneous and often vary randomly in space and time. Electromagnetic and acoustic waves propagating through and reflected from these media vary in amplitude and phase, and the interactions between the wave and the medium affect a broad range of practical problems such as detection, identification and imaging of objects in media, inverse problems of determining medium characteristics, remote sensing of media, and communications through such media. For over 20 years, we have conducted basic research and contributed significantly to the development of the knowledge in this general field. In this research, we aim at the development of imaging and inverse scattering theories as applied to the detection of objects in inhomogeneous and random geophysical media and remote sensing. The theories will be based on our recent studies on general space-time, phase, angular, and polarization correlations and interferometry for inhomogeneous and random media. Specific topics to be investigated include the following: 1) Detection and imaging of objects in and near geophysical media 2) Low-grazing angle detection and 3) Pulse scattering by objects in random media.
The above studies are based on our past experience in wave scattering in random media. We stress the importance of the combined use of analytical, experimental, and Monte Carlo numerical simulations, which has proven to be effective and essential in our research. Our study should lead to improved theories for imaging and inverse problems for objects in geophysical environments, such as oceans, beaches, and ocean surfaces and bottoms, which are of direct concern to the Navy.
References:
T.-K. Chan, Y. Kuga, A. Ishimaru, and C. T. C. Le, "Experimental studies of bistatic scattering from two-dimensional conducting random rough surfaces," IEEE Transactions on Geoscience and Remote Sensing, 34:3, May 1996, pp. 674-680.
C. T. C. Le, Y. Kuga and A. Ishimaru, "Angular correlation function based on the second-order Kirchhoff approximation and comparison with experiments," Journal of the Optical Society of America A, 13:5, May 1996, pp. 1057-1067.
Principal Investigators: Akira Ishimaru and Yasuo Kuga
Sponsor: Office of Naval Research
Abstract: This grant entitled, "Low-Grazing Angle Pulse Scattering and Detection of Objects near Surfaces" is to augment the parent award on "Object Detection, Imaging and Inverse Scattering in Geophysical Media" by supporting two Ph.D. students. It is expected that this research will produce theoretical models and computer codes that will be directly applicable to the DoD mission, and that the students will gain valuable experience in analytical, experimental, and numerical studies in these areas of critical importance to the Navy.
Applied Electromagnetics and Remote Sensing Lab
Principal Investigators: Yasuo Kuga and Akira Ishimaru
Sponsor: Jet Propulsion Laboratory
Abstract: We are conducting a study of ionospheric/tropospheric effects on both polarimetric and interferometric SAR operations for the JPL/NASA Advanced Radar Technology Program (ARTP). The primary objective of the ARTP program is to develop advanced spaceborne radar technologies for future radar missions to reduce mission-life cost. ARTP is working toward a new generation of polarimetric/interferometric SAR which will not suffer image distortions due to the ionosphere and troposphere. We will study these effects and possible compensation techniques for given SAR configurations. In particular, we will investigate the effects of Faraday rotation due to the ionosphere, phase distortion due to the ionosphere and troposphere, attenuation due to the troposphere, and decorrelation of the ionosphere and troposphere in the repeat pass operation. These effects will be characterized at P, L, C, and X bands using realistic models.
Updated February 5, 1999