In this paper, to reduce the non-linear phase error caused by gamma effect of the digital projector, a novel phase difference extraction method is proposed. First, through multi-layer discrete wavelet decomposition(DW...In this paper, to reduce the non-linear phase error caused by gamma effect of the digital projector, a novel phase difference extraction method is proposed. First, through multi-layer discrete wavelet decomposition(DWT), the components of the original phase difference at different frequencies are extracted. Subsequently, the effective components are taken by the orthogonal matching pursuit(OMP) algorithm, and the phase difference is reconstructed. According to the upper and lower envelopes of the original phase difference extracted by cubic spline interpolation, the residual threshold of OMP is set. According to the results of three-dimensional(3-D) reconstruction experiment on a standard sphere, the proposed method is capable of reducing the errors in the original phase difference and achieving a better imaging result.展开更多
Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome...Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome this defect, a finite-difference method in the frequency-space domain is introduced in the migration process, because it can adapt to strong lateral velocity variation and the coefficient is optimized by a hybrid genetic and simulated annealing algorithm. The two measures improve the precision of the approximation dispersion equation. Thus, the imaging effect is improved for areas of high-dip structure and strong lateral velocity variation. The migration imaging of a 2-D SEG/EAGE salt dome model proves that a better imaging effect in these areas is achieved by optimized phase-shift migration operator plus a finite-difference method based on a hybrid genetic and simulated annealing algorithm. The method proposed in this paper is better than conventional methods in imaging of areas of high-dip angle and strong lateral velocity variation.展开更多
高压电缆会产生强电磁场,使得产生热-力-电多物理场耦合现象,降低电缆管道测距的偏振纯度。为此,提出基于激光偏振相位差补偿的电缆管道测距方法。通过琼斯矢量描述光在系统内的偏振状态。结合改进移动最小二乘(Improved Moving Least S...高压电缆会产生强电磁场,使得产生热-力-电多物理场耦合现象,降低电缆管道测距的偏振纯度。为此,提出基于激光偏振相位差补偿的电缆管道测距方法。通过琼斯矢量描述光在系统内的偏振状态。结合改进移动最小二乘(Improved Moving Least Squares,IMLS)算法处理反射激光信号的模糊性,测量电缆管道距离。采用扫描腔长技术测定透过率特性,实现偏振光在环形光腔中的稳定传播和偏振态的有效转换,进而通过振幅均衡和相位差补偿,实现了电缆管道距离的精准测量。实验结果表明,所提方法可以获取更加精准的电缆管道测距结果,提高了管道测距的偏振纯度。展开更多
A newalgorithm, called Magnitude Cut, to recover a signal from its phase in the transform domain, is proposed.First, the recovery problem is converted to an equivalent convex optimization problem, and then it is solve...A newalgorithm, called Magnitude Cut, to recover a signal from its phase in the transform domain, is proposed.First, the recovery problem is converted to an equivalent convex optimization problem, and then it is solved by the block coordinate descent（ BCD） algorithm and the interior point algorithm. Finally, the one-dimensional and twodimensional signal reconstructions are implemented and the reconstruction results under the Fourier transform with a Gaussian random mask（ FTGM）, the Cauchy wavelets transform（ CWT）, the Fourier transform with a binary random mask（ FTBM） and the Gaussian random transform（ GRT） are also comparatively analyzed. The analysis results reveal that the M agnitude Cut method can reconstruct the original signal with the phase information of different transforms; and it needs less phase information to recover the signal from the phase of the FTGM or GRT than that of FTBM or CWT under the same reconstruction error.展开更多
基金This work has been supported by the National Natural Science Foundation of China(No.61873333)the Fundamental Research Funds of Shandong University in China(No.2018JCG06)+3 种基金the Shandong Provincial Natural Science Foundation of China(Nos.ZR2017PEE023 and ZR2017BF007)the National Key Research and Development Project(No.2018YFE02013)the Key Research and Development Plan of Shandong Province(No.2017CXGC0610)the Young Scholars Program of Shandong University(No.2016WLJH30).
文摘In this paper, to reduce the non-linear phase error caused by gamma effect of the digital projector, a novel phase difference extraction method is proposed. First, through multi-layer discrete wavelet decomposition(DWT), the components of the original phase difference at different frequencies are extracted. Subsequently, the effective components are taken by the orthogonal matching pursuit(OMP) algorithm, and the phase difference is reconstructed. According to the upper and lower envelopes of the original phase difference extracted by cubic spline interpolation, the residual threshold of OMP is set. According to the results of three-dimensional(3-D) reconstruction experiment on a standard sphere, the proposed method is capable of reducing the errors in the original phase difference and achieving a better imaging result.
基金the Open Fund(PLC201104)of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology)the National Natural Science Foundation of China(No.61072073)the Key Project of Education Commission of Sichuan Province(No.10ZA072)
文摘Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome this defect, a finite-difference method in the frequency-space domain is introduced in the migration process, because it can adapt to strong lateral velocity variation and the coefficient is optimized by a hybrid genetic and simulated annealing algorithm. The two measures improve the precision of the approximation dispersion equation. Thus, the imaging effect is improved for areas of high-dip structure and strong lateral velocity variation. The migration imaging of a 2-D SEG/EAGE salt dome model proves that a better imaging effect in these areas is achieved by optimized phase-shift migration operator plus a finite-difference method based on a hybrid genetic and simulated annealing algorithm. The method proposed in this paper is better than conventional methods in imaging of areas of high-dip angle and strong lateral velocity variation.
文摘高压电缆会产生强电磁场,使得产生热-力-电多物理场耦合现象,降低电缆管道测距的偏振纯度。为此,提出基于激光偏振相位差补偿的电缆管道测距方法。通过琼斯矢量描述光在系统内的偏振状态。结合改进移动最小二乘(Improved Moving Least Squares,IMLS)算法处理反射激光信号的模糊性,测量电缆管道距离。采用扫描腔长技术测定透过率特性,实现偏振光在环形光腔中的稳定传播和偏振态的有效转换,进而通过振幅均衡和相位差补偿,实现了电缆管道距离的精准测量。实验结果表明,所提方法可以获取更加精准的电缆管道测距结果,提高了管道测距的偏振纯度。
基金The National Natural Science Foundation of China(No.6120134461271312+7 种基金11301074)the Specialized Research Fund for the Doctoral Program of Higher Education(No.2011009211002320120092120036)the Program for Special Talents in Six Fields of Jiangsu Province(No.DZXX-031)the Natural Science Foundation of Jiangsu Province(No.BK2012329BK2012743)the United Creative Foundation of Jiangsu Province(No.BY2014127-11)the"333"Project(No.BRA2015288)
文摘A newalgorithm, called Magnitude Cut, to recover a signal from its phase in the transform domain, is proposed.First, the recovery problem is converted to an equivalent convex optimization problem, and then it is solved by the block coordinate descent（ BCD） algorithm and the interior point algorithm. Finally, the one-dimensional and twodimensional signal reconstructions are implemented and the reconstruction results under the Fourier transform with a Gaussian random mask（ FTGM）, the Cauchy wavelets transform（ CWT）, the Fourier transform with a binary random mask（ FTBM） and the Gaussian random transform（ GRT） are also comparatively analyzed. The analysis results reveal that the M agnitude Cut method can reconstruct the original signal with the phase information of different transforms; and it needs less phase information to recover the signal from the phase of the FTGM or GRT than that of FTBM or CWT under the same reconstruction error.
