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Your search keyword '"Zhou, Haoqiu"' showing total 33 results
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33 results on '"Zhou, Haoqiu"'

5. Maximum Likelihood Data Fusion With Optimal Similarity Constraints for Full-Polarimetric RoPeR Imaging of Martian Regolith

Author

Zhou, Haoqiu, Feng, Xuan, Dong, Zejun, and Liu, Cai

Abstract

The Zhurong rover of the Chinese Tianwen-1 mission is equipped with a Mars rover penetrating radar (RoPeR). The high-frequency CH-2 antenna adopts a full-polarimetric (FP) acquisition mode to map the fine structure of the Martian regolith. However, the data from different polarimetric channels characterize different features of the subsurface. The accurate interpretation of regolith structure relies on a clear and comprehensive imaging result. This article proposes a new data fusion algorithm to achieve this goal, which is called the maximum likelihood method with optimal similarity constraints (ML-OSC). A unique loss function is constructed to guarantee the similarity between the fusion result and source radargrams and simultaneously consider the amplitude difference in different channel data. FP ground penetrating radar (FP-GPR) experiments on three typical targets are performed in the laboratory. The comparisons with three normal methods validate the effectiveness and superiority of the proposed method. Finally, the proposed method is applied to the field FP-RoPeR data fusion imaging. Several subsurface structures are analyzed in detail to verify its effectiveness in Martian regolith imaging. The proposed method provides new and complete imaging results of Martian regolith, which will lead to a more accurate interpretation of it in the future.

Published
2024
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6. Super-Resolution Detection of Millimeter-Scale Fractures With Fluid Flow Using Time-Lapse Full-Polarimetric GPR and Anisotropy Analysis

Author

Dong, Zejun, Feng, Xuan, Zhou, Haoqiu, Zhang, Minghe, Liu, Qian, An, Yafei, Zhang, Yinghao, Yang, Jiarun, Liang, Wenjing, Yu, Yue, and Liu, Cai

Abstract

Fractures with fluid flow can lead to the damage of rock carving relics. During the detection of fractures, millimeter-scale fractures are usually difficult to determine due to their small apertures. Considering the rapid variation of water content in the fracture seepage zone can lead to anisotropy, this article proposes a new methodology to detect these millimeter-scale fractures with fluid flow using a time-lapse full-polarimetric ground penetrating radar (FP-GPR) scheme and an anisotropy analysis method. The time-lapse FP-GPR detection can monitor the water flow in the fracture and the infiltration in the rock, and the Freeman decomposition, H-Alpha decomposition, and a polarimetric phase (PP) feature are adopted to quantify and analyze the anisotropic effects over time. In the numerical test, we adopt hydrological modeling to build realistic dielectric models for time-lapse FP-GPR simulations. The results indicate that the variations of water contents and several polarimetric features, i.e., the surface-like scattering power, the double-bounce scattering power, and the averaged scattering angle, are consistent and are essentially related to the anisotropy of the seepage zone. Finally, we introduce the field tests performed at the experimental station of the Dazu Rock Carvings in Chongqing, China, which contain two cases I and II. Case I is an experiment on a surface fracture of a cliff, whereas case II is a detection test of a buried fracture. The results verify the effectiveness of the proposed methodology.

Published
2024
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33. Local Freeman Decomposition for Robust Imaging and Identification of Subsurface Anomalies Using Misaligned Full-Polarimetric GPR Data.

Author

Zhou, Haoqiu, Feng, Xuan, Dong, Zejun, Liu, Cai, Liang, Wenjing, and An, Yafei

Subjects
*GROUND penetrating radar, *SYNTHETIC aperture radar, *PERMITTIVITY, *ANTENNA arrays, *HUMAN error
Abstract

A full-polarimetric ground penetrating radar (FP-GPR) uses an antenna array to detect subsurface anomalies. Compared to the traditional GPR, FP-GPR can obtain more abundant information about the subsurface. However, in field FP-GPR measurements, the arrival time of the received electromagnetic (EM) waves from different channels cannot be strictly aligned due to the limitations of human operation errors and the craftsmanship of the equipment. Small misalignments between the radargrams acquired from different channels of an FP-GPR can lead to erroneous identification results of the classic Freeman decomposition (FD) method. Here, we propose a local Freeman decomposition (LFD) method to enhance the robustness of the classic FD method when managing with misaligned FP-GPR data. The tests on three typical targets demonstrate that misalignments will severely interfere with the imaging and the identification results of the classic FD method for the plane and dihedral scatterers. In contrast, the proposed LFD method can produce smooth images and accurate identification results. Besides, the identification of the volume scatterer is not affected by misalignments. A test of ice-fracture detection further verifies the capability of the LFD method in field measurements. Due to the different relative magnitudes of the permittivity of the media on two sides of the interfaces, the ice surface and ice fracture show the features of surface-like and double-bounce scattering, respectively. However, the definition of double-bounce scattering is different from the definition in polarimetric synthetic aperture radar (SAR). Finally, a quantitative analysis shows that the sensitivities of the FD and LFD methods to misalignments are related to both the type of target and the polarized mode of the misaligned data. The tolerable range of the LFD method for misalignments is approximately ±0.2 times the wavelength of the EM wave, which is much wider than that of the FD method. In most cases, the LFD method can guarantee an accurate result of identification. [ABSTRACT FROM AUTHOR]

Published
2022
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