Sparse reconstruction algorithms for nonlinear microwave imaging

Zaimaga, Hidayet; Fraysse, Aurélia; Lambert, Marc

doi:10.23919/eusipco.2017.8081300

Cited by 4 publications

(2 citation statements)

References 21 publications

(25 reference statements)

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“…Mixed norms [37] such as 2,1 or ∞,1 are usually employed to impose both sparsity and structural prior information in the optimization problem [38]. In [39], as the row vectors of the contrast source share a common non-zero support, a two-step sparse recovery process is investigated where the 2,1 norm is to enforce joint sparsity on the contrast source.…”

Section: Introductionmentioning

confidence: 99%

Group Sparsity Penalized Contrast Source Solution Method for 2-D Non-Linear Inverse Scattering

Zhang

Lambert

Fraysse

et al. 2022

IEEE Open J. Antennas Propag.

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A group sparsity penalized CSI in the wavelet domain is proposed to alleviate ill-posedness within the framework of a contrast-source inversion (CSI) method. It is then applied to the retrieval of a large inhomogeneous dielectric scatterer from time-harmonic single-frequency data. As dependency exists between wavelet coefficients at different scales, referred to as the parent-child relationship, it enables to yield the wavelet quad tree structure. Therefore, wavelet coefficients can be regarded not only as pixel-wise sparse, but also group-wise sparse. Focus is put on using the dual-tree complex wavelet transform (CWT) to properly achieve the sought-after group-wise sparse representation of the spatial distribution of the contrast. It provides a 2,1 norm which is added to the standard cost functional to enforce group sparsity onto the wavelet coefficients of the spatially-varying contrast. The replication strategy is combined with the proximal method in order to solve the overlapping group penalized problem. Simulations from synthetic data in different configurations with in particular different signal-to-noise ratios illustrate pros and cons of the proposed method. The approach is shown to overcome the standard CSI method in demanding situations. Comparisons with the discrete wavelet transform (DWT) as usually performed and the 1 norm confirm the advantage of the proposed methodology.

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Section: Introductionmentioning

confidence: 99%

Group Sparsity Penalized Contrast Source Solution Method for 2-D Non-Linear Inverse Scattering

Zhang

Lambert

Fraysse

et al. 2022

IEEE Open J. Antennas Propag.

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“…However, they are limited to the determination of the geometrical features and location of objects and cannot provide information regarding the dielectric properties. On the other hand, the application of non-linear inverse scattering algorithms enables the obtainment of the dielectric properties of the concealed objects at the expense of a time-consuming reconstruction process due to their iterative approach [35][36][37]. Moreover, in comparison to linear inverse scattering, the non-linear approach can be unreliable due to the presence of the local minima problem.…”

Section: Introductionmentioning

confidence: 99%

Indirect microwave holography and Through-Wall imaging

Yurduseven¹,

Elsdon²

2019

Frelsi

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In this paper, a review of indirect microwave holography for through-wall imaging is presented. Indirect microwave holography is an imaging technique, enabling the complex object scattered fields (amplitude and phase) to be mathematically recovered from intensity-only, scalar microwave measurements. By removing the requirement to use vector measurement equipment to directly measure the complex fields, indirect microwave holography significantly reduces the cost of the imaging system and simplifies the hardware implementation. The application of a back-propagation algorithm enables the reconstructed amplitude and phase images to be obtained at the plane of the concealed object. In order to demonstrate the validity of the reviewed approach, experimental work is carried out on a metallic gun concealed under a 5 cm thick plywood wall and it is demonstrated that the indirect microwave holographic TWI can produce good resolution amplitude and phase images when back-propagation is applied. TWI of a concealed dielectric box representing non-metallic ordnance is also performed to demonstrate the ability of the technique to reconstruct through-wall images of concealed dielectric objects. An investigation of the resolution characteristics of the system suggests diffraction limited resolution can be achieved.

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