Computational imaging using a mode-mixing cavity at microwave frequencies

Fromentèze, Thomas; Yurduseven, Okan; Imani, Mohammadreza F.; Gollub, Jonah N.; Decroze, Cyril; Carsenat, David; Smith, David R.

doi:10.1063/1.4921081

Cited by 155 publications

(125 citation statements)

References 26 publications

Supporting

Mentioning

123

Contrasting

Order By: Relevance

“…To this end, a metallic leaky cavity of 28.5 × 28.5 × 15.2 cm 3 was created ( Fig. 10), inspired by a computational imaging prototype introduced in [22]. The front plate is perforated by a 15 × 15 cm 2 square array of circular holes randomly set on a 0.6 cm uniform grid.…”

Section: Pratical Implementation and Experimental Resultsmentioning

confidence: 99%

Phaseless computational imaging with a radiating metasurface

Fromentèze¹,

Liu²,

Boyarsky³

et al. 2016

Opt. Express

Self Cite

View full text Add to dashboard Cite

Computational imaging modalities support a simplification of the active architectures required in an imaging system and these approaches have been validated across the electromagnetic spectrum. Recent implementations have utilized pseudo-orthogonal radiation patterns to illuminate an object of interest-notably, frequency-diverse metasurfaces have been exploited as fast and low-cost alternative to conventional coherent imaging systems. However, accurately measuring the complex-valued signals in the frequency domain can be burdensome, particularly for sub-centimeter wavelengths. Here, computational imaging is studied under the relaxed constraint of intensity-only measurements. A novel 3D imaging system is conceived based on 'phaseless' and compressed measurements, with benefits from recent advances in the field of phase retrieval. In this paper, the methodology associated with this novel principle is described, studied, and experimentally demonstrated in the microwave range. A comparison of the estimated images from both complex valued and phaseless measurements are presented, verifying the fidelity of phaseless computational imaging.

show abstract

Section: Pratical Implementation and Experimental Resultsmentioning

confidence: 99%

Phaseless computational imaging with a radiating metasurface

Fromentèze¹,

Liu²,

Boyarsky³

et al. 2016

Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…Highly dispersive customized apertures, e.g. complex metamaterials [47], [49], [50] or leaky reverberant cavities [46], [48], form virtual transceiver arrays. These expand excitations at sufficiently different frequencies into distinct spatial codes, i.e.…”

Section: A Related Workmentioning

confidence: 99%

Notice of Removal: Random incident sound waves for fast compressed pulse-echo ultrasound imaging

Schiffner

Schmitz

2017

2017 IEEE International Ultrasonics Symposium (IUS)

View full text Add to dashboard Cite

Established image recovery methods in fast ultrasound imaging, e.g. delay-and-sum, trade the image quality for the high frame rate. Cutting-edge inverse scattering methods based on compressed sensing (CS) disrupt this tradeoff via a priori information. They iteratively recover a high-quality image from only a few sequential pulse-echo measurements or less echo signals, if (i) a known dictionary of structural building blocks represents the image almost sparsely, and (ii) their individual pulse echoes, which are predicted by a linear model, are sufficiently uncorrelated. The exclusive modeling of the incident waves as steered plane waves or cylindrical waves, however, has so far limited the convergence speed, the image quality, and the potential to meet condition (ii).Motivated by the benefits of randomness in CS, a novel method for the fast compressed acquisition and the subsequent recovery of images is proposed to overcome these limitations. It recovers the spatial compressibility fluctuations in weakly-scattering soft tissue structures, where an orthonormal basis meets condition (i), by a sparsity-promoting ℓq-minimization method, q ∈ [0; 1]. A realistic d-dimensional model, d ∈ {2, 3}, accounting for diffraction, single monopole scattering, the combination of powerlaw absorption and dispersion, and the specifications of a planar transducer array, predicts the pulse echoes of the individual basis functions. Three innovative types of incident waves, whose syntheses leverage random apodization weights, time delays, or combinations thereof, aid in meeting condition (ii).In two-dimensional numerical simulations, single realizations of these waves outperform the prevalent quasi-plane wave for both the canonical and the Fourier bases. They significantly decorrelate the pulse echoes, e.g. they reduce the full extents at half maximum of the point spread functions by up to 73.7 %. For a tissue-mimicking phantom and q ∈ {1, 0.5}, they improve the convergence speed and the image quality in terms of the mean structural similarity indices and the relative root meansquared errors by up to {2.7 %, 22.9 %}, {44.1 %, 55.5 %}, and {42 %, 60.5 %}, respectively.Index Terms-random incident waves, inverse scattering, compressed sensing, sparse regularization, ultrafast ultrasound imaging, computational ultrasound imaging, fast multipole method, GPU computing

show abstract

“…Hence, to obtain a metamaterial aperture that generates the frequency-agile far-field patterns that are as orthogonal as possible, elements distributed on the aperture must have a strong resonance with a high Q-value. Other approaches to frequency-diverse imaging have also been pursued, including multiply scattering structures, such as mode-mixing cavities and dynamic metamaterial apertures [8][9][10]. Fractal models have been used to design fractal antennas with very special properties: about one-tenth of a wavelength and a pre-fractal geometrical configuration [11] could be used in metamaterial miniaturized technology, which is needed for coherent imaging.…”

Section: Introductionmentioning

confidence: 99%

Measurement Matrix Analysis and Radiation Improvement of a Metamaterial Aperture Antenna for Coherent Computational Imaging

Kou

Tian

et al. 2017

Applied Sciences

View full text Add to dashboard Cite

Abstract:A metamaterial aperture antenna (MAA) that generates frequency-diverse radiation field patterns has been introduced in the context of microwave wave imaging to perform compressive image reconstruction. This paper presents a new metamateriapl aperture design, which includes two kinds of metamaterial elements with random distribution. One is a high-Q resonant element whose resonant frequency is agile, and the other one is a low-Q element that has a high radiation efficiency across frequency band. Numerical simulations and measurements show that the radiation efficiency of up to 60% can be achieved for the MAA and the far-field patterns owns good orthogonality, when using the complementary electric-field-coupled (CELC) element and the complementary Jerusalem cross (CJC) element with a random distribution ratio of 4 to 1, which could be effectively used to reconstruct the target scattering scene.

show abstract

Computational imaging using a mode-mixing cavity at microwave frequencies

Cited by 155 publications

References 26 publications

Phaseless computational imaging with a radiating metasurface

Phaseless computational imaging with a radiating metasurface

Notice of Removal: Random incident sound waves for fast compressed pulse-echo ultrasound imaging

Measurement Matrix Analysis and Radiation Improvement of a Metamaterial Aperture Antenna for Coherent Computational Imaging

Contact Info

Product

Resources

About