There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

https://biblio.ugent.be/publication/685594/file/1130605.pdf

Review of Particle Physics

/pdf/review-of-particle-physics-1996-1997-jeg703df6k.pdf

Review of Particle Physics, 1996-1997

Low-energy phenomenology of superstring-inspired E6 models

In this paper, we examine the role of polarimetry in synthetic aperture radar (SAR) interferometry. We first propose a general formulation for vector wave interferometry that includes conventional scalar interferometry as a special case. Then, we show how polarimetric basis transformations can be introduced into SAR interferometry and applied to form interferograms between all possible linear combinations of polarization states. This allows us to reveal the strong polarization dependency of the interferometric coherence. We then solve the coherence optimization problem involving maximization of interferometric coherence and formulate a new coherent decomposition for polarimetric SAR interferometry that allows the separation of the effective phase centers of different scattering mechanisms. A simplified stochastic scattering model for an elevated forest canopy is introduced to demonstrate the effectiveness of the proposed algorithms. In this way, we demonstrate the importance of wave polarization for the physical interpretation of SAR interferograms. We investigate the potential of polarimetric SAR interferometry using results from the evaluation of fully polarimetric interferometric shuttle imaging radar (SIR)-C/X-SAR data collected during October 8-9, 1994, over the SE Baikal Lake Selenga delta region of Buriatia, Southeast Siberia, Russia.

Polarimetric SAR interferometry

ALIS is a hand-held dual-sensor developed for humanitarian demining. The dual-sensor ALIS is equipped with a metal detector and a GPR (ground penetrating radar). An unique and novel sensor tracking system, which can record the GPR and metal detector signal with its location is equipped in ALIS. Due to its sensor location information, we can reconstruct buried land mine images after data acquisition. The image reconstruction, or migration processing drastically increases the quality of the image of the buried objects. ALIS evaluation test was conducted in Croatia in October 2007. Then after, we stared a half-year evaluation test of ALIS in QC test in Croatia in December 2007. This test will be conducted in various soil and environmental conditions in Croatia.

ALIS development for humanitarian demining and its evaluation tests

This paper presents the ground penetrating radar (GPR) performance for determining near-surface soil contaminants quantitatively. We have carried out a field experiment at an old gas station site contaminated due to leakage of gasoline from tanks and pipes. GPR data were acquired using 100MHz antennas and imaged the geological structures. The extent and depth of contaminated zone was mapped using GPR data by a mapping method based on a correlation algorithm. The soil properties including water content, resistivities and concentration of total petroleum hydrocarbons (TPH) were analyzed using core samples. Combining the GPR data and analysis data of soil properties, the hydrocarbon contamination values can be quantitatively determined in this area.

Quantitative Determination of Hydrocarbon Contamination by GPR

We proposed a methodology to apply inverse boundary scattering transform to process complex radar data with minimum imaging artifacts. Unlike other boundary extraction-based methods, such as shape estimation algorithm based on boundary scattering transform and extraction of directly scattered waves, the developed approach does not rely on peaks of signals, does not require to connect points to quasi wavefronts, and it is numerically stable and robust. Instead of quasi wavefronts extraction, the method process huge amount of the wave-tracking lines, match the weight values to them, and apply multistage filtration based on the first and second derivatives. It makes the developed method to be able to be used for processing cluttered data like GPR. Using the experimentally obtained GPR profile, we demonstrated that the method allows separating the buried objects from clutter, noise, and imaging artifacts. Compared to conventional diffraction stacking method, weighted envelopes transformation results show good clearness of the targets, which makes the profiles easy to interpret. A number of filtration parameters over huge number of extracted features provide good flexibility and wide applicability of our approach.

Near Range Radar Image Reconstruction Algorithm by Weighted Envelopes Transformation

Wide band stepped-frequency ground penetrating radar

Finite difference time domain (FDTD) method has been accelerated on the Cell Broadband Engine (Cell B.E.). However the problem has arisen that speedup is limited by the bandwidth of the main memory on large-scale analysis. As described in this paper, we propose a novel algorithm and implement FDTD using it. We compared the novel algorithm with results obtained using region segmentation, thereby demonstrating that the proposed algorithm has shorter calculation time than that provided by region segmentation.

Motoyuki Sato

Papers

ALIS development for humanitarian demining and its evaluation tests

Quantitative Determination of Hydrocarbon Contamination by GPR

Near Range Radar Image Reconstruction Algorithm by Weighted Envelopes Transformation

Wide band stepped-frequency ground penetrating radar

Acceleration of FDTD Method Using a Novel Algorithm on the Cell B.E.