Microwave Imaging of Soil Water Diffusion Using the Linear Sampling Method

Abstract

International audienceThis letter deals with the monitoring of the volumetric water content of a soil column in a fully controlled environment by means of a noninvasive microwave imaging system. Indeed, soil moisture is an important piece of information to improve fluid flow modeling or to better understand the water uptake by plant roots. In this letter, we address the problem of recovering the footprint of soil moisture evolution with respect to time using a built-in laboratory microwave setup coupled to a robust qualitative microwave imaging method: the linear sampling method (LSM). The evolution of the water content in the soil is ruled by the Richards equations and stored at different time steps. The associated maps of soil water content are converted into permittivity maps using the Dobson model. Electromagnetic scattered fields are then computed with finite-element software. We have tested the LSM in a situation that can be encountered in agricultural soils where the water content is not homogeneous. We show that the evolution of the soil water content can be qualitatively monitored with the LSM. We also point out that the source is more precisely located by considering the evolution in time of the singular system of the multistatic matrix (multiple signal classification method)

Simulation of Multi-Layer Rough Surfaces Media in the Passive Millimeter-Wave Imaging

“…For single layer, the second item in Equation (2), T 2tal (θ 1 , ϕ 1 ), is only the total brightness temperature of the second layer after diffused reflection in direction (θ 1 , ϕ 1 ), which can be expressed by Equation (3).…”

“…Passive millimeter-wave imaging (PMMW), as a hot research topic in recent years, is widely used in various fields [1][2][3]. Past researches of PMMW imaging are concentrated in relatively short imaging distances.…”

Microwave Imaging Within the Interval Analysis Framework

“…To investigate on the robustness of the IA-based inversion to noisy data, the reconstruction of the same scatterer profile of the previous example has been performed by varying the noise level within the range SN R = [5,50] [dB]. As indicated by the amount of the error indexes in Fig.…”

“…This is indicative of the attention on this subject from academic, industrial, and governmental researchers and experts. As a matter of fact, the range of potential applications is wide and it spans from the more traditional (e.g., geophysical investigations and remote sensing [3][4][5], nondestructive testing and evaluation [6][7][8][9][10], and medical imaging [11][12][13][14][15][16][17][18]) to the latest ones mainly related to security and surveillance (e.g., throughthe-wall imaging [19][20][21][22][23][24]) up to more recent applications [25].…”

Calibration of a multistatic planar scanner for subsurface imaging

“…Monitoring the subsoil is of interest in various areas [1], e.g., for anti-personal mine detection [2], for water pipe leakage detection [3], for soil moisture characterization [4], ... Electromagnetic waves are of particular interest as these waves are sensitive -via the permittivity -to the soil properties. The soil is usual probed with an ultra-wideband electromagnetic wave working with temporal pulses [5] or in a step-frequency mode [6].…”