Tadahiro Negishi

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Experimental data are used to validate a novel inversion scheme, based on a Conjugate Gradient algorithm. The proposed inversion provides actionable reconstruction results at a fraction of the computational effort needed by classical regularization techniques. Additionally, Conjugate Gradient allows us to introduce physical bounds on the solution returned,(More)
We describe the use of numerical Green's functions applied to Radio Frequency Tomography. RF Tomography relies on a linear operator in matrix form, which depends on a Green's function. The availability of the correct Green's function can be an important limitation when imaging in non-trivial scenarios. If the function cannot be found analytically, numerical(More)
Multipath is exploited to image targets that are hidden due to lack of line of sight (LOS) path in urban environments. Urban radar scenes include building walls, therefore creating reflections causing multipath returns. Conventional processing via synthetic aperture beamforming algorithms do not detect or localize the target at its true position. To remove(More)
In this paper, we investigated the used of the Algebraic Reconstruction Technique to obtain images of dielectric targets. A standard implementation of ART has been modified so as to impose physical bounds on the image obtained. Our results show images that in general outperform reconstruction obtained with TSVD (or CG). Images are less noisy, more sharp,(More)
Experimental tests to validate Radio Frequency Tomography (RFT) in the case of an inhomogeneous scenario are reported in this work. The experiments dealt with the imaging of objects buried in a box surrounded by air and filled with sand or gravel. RFT is based on the linear model provided by Born approximation and assumes that multiple transmitters and(More)
Multistatic SAR/ISAR can be described and generalized using the principles of radar (or radio frequency) tomography. In radar tomography, distributed transmitters and receivers sense a region of interest using suitable waveforms. Using the principles of linear scattering (Born approximation), a (linear) relation exists between the measured returns and the(More)