Sparsity-Driven Reconstruction Technique for Microwave/Millimeter-Wave Computational Imaging

Abstract

Numerous prototypes of computational imaging systems have recently been presented in the microwave and millimeter-wave domains, enabling the simplification of associated active architectures through the use of radiating cavities and metasurfaces that can multiplex signals encoded in the physical layer. This paper presents a new reconstruction technique leveraging the sparsity of the signals in the time-domain and decomposition of the sensing matrix by support detection, the size of the computational inverse problem being reduced significantly without compromising the image quality.

Terahertz Frequency-Scaled Differential Imaging for Sub-6 GHz Vehicular Antenna Signature Analysis

“…In the first case (the vehicle antenna in the ON, short-circuited state), the total scattered fields For the compact vehicle antenna, resonant antennas are utilized in most vehicles. Then, it may be considered: (i) that interactions of a high order, such as reflections among external illuminating geometry and vehicle antenna or vehicular platform, may be neglected since they are much smaller than the rest; and (ii) that the scattered fields produced by the unchanged parts, like the vehicular platform and the structure of the antenna, are approximately the same for both states of the vehicle antenna: (7) being related to the currents produced by the radiating mode of the vehicle antenna, and Equation (4) becomes:…”

“…In [ 6 ], the operating frequency is increased to 522 GHz. Finally, to conclude the background review, a novel reconstruction process in time domain operating in the microwave and mmWave frequency bands is presented in [ 7 ].…”

Enhancing Millimeter-Wave Computational Interferometric Imaging

“…Even if this paper focuses only on the use of matrix inversion reconstruction, it is possible to propose an alternative based on Fast Fourier Transforms to the R ψ + matrix. Similarly to the approaches developed in [20], [24], [38], this work proposes to simplify image reconstructions by using an intermediate step of estimating the correlation of antenna signals. However, the formalism proposed here is distinguished by the use of a fully matrix-based method, in opposition to the previously developed equalization techniques [39].…”

Ghost Image Removal Using Physical Layer Spatial Asymmetry in Frequency-Diverse Computational Imaging

“…Computational imaging is the process through advanced processing algorithms to reconstruct images from a set of indirect measurements [1][2][3][4][5][6][7][8]. In contrast to conventional imaging modalities with a limited data acquisition speed, such as synthetic aperture radar [9][10][11], and a complex hardware layer, such as phased arrays [12,13], frequencydiverse computational imaging has recently emerged as a promising alternative [14][15][16][17][18][19][20][21].…”