Huang Xiaoyun

Bio: Huang Xiaoyun is an academic researcher from Xiamen University. The author has contributed to research in topics: Radar & Ground-penetrating radar. The author has an hindex of 1, co-authored 5 publications receiving 22 citations.

Hybrid Polarimetric GPR Calibration and Elongated Object Orientation Estimation

Abstract: Ground penetrating radar (GPR) has been widely applied to the detection of subsurface elongated targets, such as underground pipes, concrete rebars, and subsurface fractures. The orientation angle of a subsurface elongated target can hardly be delineated by a commercial single-polarization GPR system. In this paper, a hybrid dual-polarimetric GPR system, which consists of a circularly polarized transmitting antenna and two linearly polarized receiving antenna, is employed to detect buried elongated objects. A polarimetric calibration experiment using a gridded trihedral is carried out to correct the imbalances and cross talk between the two receiving channels. A full-polarimetric scattering matrix is extracted from the double-channel GPR signals reflected from a buried elongated object. An improved Alford rotation method is proposed to estimate the orientation angle of the elongated object from the extracted scattering matrix, and its accuracy is validated by a numerical test. A laboratory experiment was further conducted to detect five metal rebar buried in dry sand at different orientation angle relative to the GPR scan direction. The maximum relative error of the estimated angles of the buried rebars in the migrated GPR images is less than 5%. It is concluded that radar polarimetry can provide not only richer information than single-polarization GPR, but also a reliable approach for orientation estimation of a subsurface elongated object.

Estimating Azimuth of Subsurface Linear Targets By Polarimetric GPR

Abstract: Ground penetrating radar (GPR) has been widely applied to detection of subsurface linear targets, such as underground pipes and reinforced rebars in concrete structures. The azimuth direction of a subsurface linear target can be hardly delineated by a commercial single-polarization GPR system. In this paper, a hybrid dual-polarimetric GPR system is employed to detect buried linear objects. A full-polarimetric scattering matrix is extracted from the double-channel GPR reflection signal. A rotation transformation is applied to the scattering matrix to estimate the target azimuth angle. A laboratory experiment was conducted to detect four metal rebars buried in dry sand at different azimuth angle relative to the GPR scan direction. The maximum error of the estimated azimuth direction is less than 15%. It is concluded that radar polarimetry can provide richer information than single-polarization GPR.

Complete polarization foundation synthetic aperture radar system

Abstract: The invention discloses a complete polarization foundation synthetic aperture radar system comprising a foundation synthetic aperture radar automatic measuring device, a computer, and a radar host; the foundation synthetic aperture radar automatic measuring device comprises a transmission nut, a roller guide rail, a support, circular polarized antennas, a double-pole double-throw switch, and a stepping motor; the transmission nut is fixed on the bottom of the support; the stepping motor is arranged on the left end of the roller guide rail; the double-pole double-throw switch is arranged on the top in the support; a complete polarization antenna array is arranged in the support; the circular polarized antennas are arranged on the complete polarization antenna array. Compared with a conventional detection method, the complete polarization foundation synthetic aperture radar system has the following advantages: the complete polarization antenna array has higher distinguish precision than a single polarization antenna; the system is fast in data acquisition speed, and employs an automation process; the system belongs to the non-contact measuring modes, thus monitoring danger slopes.

Polarization calibration method for hybrid compact polarized ground penetrating radar system

Abstract: The invention discloses a polarization calibration method for a hybrid compact polarized ground penetrating radar system. The method comprises three steps of: firstly, establishing a calibration modelwhich includes the crosstalk parameter of a receiving antenna, the parameter of channel imbalance, the crosstalk parameter of a transmitting antenna; secondly, using a trihedral angle calibrator withgrids on a side as a detection target, substituting the scattering matrixes of grid trihedral angles in different directions into the calibration model, and calculating all crosstalk parameters and channel imbalance parameters; and thirdly, substituting the obtained crosstalk parameters and imbalance parameters into the calibration model so as to obtain calibrated antenna transmitting-receiving signals and extract a calibrated polarization scattering matrix therefrom.

Method for measuring system stability of ground penetrating radar

Abstract: The invention discloses a method for measuring system stability of a ground penetrating radar and relates to the technical field of ground penetrating radars. The method includes a calculation formulafor instability factors and time base jitters having statistical significance. The calculation formula is used for evaluating the system stability of the ground penetrating radar quantitatively. According to the invention, a radar antenna of the ground penetrating radar is disposed on the ground surface and more than 1000 direct wave signals are collected continuously in a time-triggered manner.The calculation formula calculates the instability factors and time base jitters of the ground penetrating radar and the system stability of the ground penetrating radar is evaluated by adopting an evaluation standard. According to the invention, the system stability of the ground penetrating radar is measured and a basis of reliability is provided for applications requiring quantitative analysisof radar data.

Classification of High-Spatial-Resolution Remote Sensing Scenes Method Using Transfer Learning and Deep Convolutional Neural Network

Abstract: The deep convolutional neural network (DeCNN) is considered one of promising techniques for classifying the high-spatial-resolution remote sensing (HSRRS) scenes, due to its powerful feature extraction capabilities. It is well-known that huge high-quality labeled datasets are required for achieving the better classification performances and preventing overfitting, during the training DeCNN model process. However, the lack of high-quality datasets limits the applications of DeCNN. In order to solve this problem, in this article, we propose a HSRRS image scene classification method using transfer learning and the DeCNN (TL-DeCNN) model in a few shot HSRRS scene samples. Specifically, three typical DeCNNs of VGG19, ResNet50, and InceptionV3, trained on the ImageNet2015, the weights of their convolutional layer for that of the TL-DeCNN are transferred, respectively. Then, TL-DeCNN just needs to fine-tune its classification module on the few shot HSRRS scene samples in a few epochs. Experimental results indicate that our proposed TL-DeCNN method provides absolute dominance results without overfitting, when compared with the VGG19, ResNet50, and InceptionV3, directly trained on the few shot samples.

Penetration Properties of Ground Penetrating Radar Waves Through Rebar Grids

Abstract: Ground-penetrating radar (GPR) has been widely applied to the nondestructive inspection of concrete structures such as tunnel lining, bridge deck, and retaining wall, which are usually reinforced by steel bars. The scattering of electromagnetic (EM) waves caused by the dense steel rebar embedded in the concrete structures has a severe influence on the penetration capacity of GPR waves. In this letter, the scattering and penetration characteristics of EM waves propagating through rebar net are investigated via both numerical and laboratory experiments, with an aim to select the antenna nominal frequency for a different reinforcement density. The results show that the rebar, which is perpendicular to the polarization direction of GPR waves and has a very small diameter compared with the wavelength, is almost transparent to the impinged GPR waves. The scattering and interaction of GPR waves caused by the rebar that is parallel to the polarization direction result in a shielding effect, which is manifested as a blind band in the low-frequency range in the transmitted spectrum. This result violates the rule of thumb commonly used in the GPR community, i.e., the lower frequency has a deeper GPR penetration depth. In the end, a low cutoff frequency is recommended for selecting a GPR antenna with an appropriate nominal frequency when it is used in the detection of an anomaly inside and behind a reinforced concrete structure, in which the spacing of the rebar net is known.