Jianguo Sun

Jilin University

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Fuxing Han

Jilin Province Science and Technology Department

Zhangqing Sun

Jilin Province Science and Technology Department

Yangyang Xu

Rensselaer Polytechnic Institute

Hui Sun

Southwest Jiaotong University

Zhenghui Gao

Jilin Province Science and Technology Department

Huachao Sun

Jilin Province Science and Technology Department

Mingchen Liu

National Institutes for Food and Drug Control

Xingguo Huang

Jilin University

Zeshuang Xu

Jilin Province Science and Technology Department

Xiangyu Meng

Jilin Province Science and Technology Department

Cooperative Institutions

Jilin University

Jilin Province Science and Technology Department

Jilin Medical University

Central South University

Harbin Engineering University

Ministry of Natural Resources

University of Chinese Academy of Sciences

Chinese Academy of Sciences

China National Petroleum Corporation (China)

Lanzhou Jiaotong University

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Electro-optic sampling of planar GaAs circuits using semiconductor laser

Wei Sun Maobin Yi Xiaojian Tian Jianguo Sun Gang Jia

We have describe an electro-optic sampling with a gain-switched laser and electronic phase shifter. We have measured the propagation delay in buffered FET logic (BFL) circuit and investigated the strength of the crosstalk.

Crosstalk

Phase shift module

10.1109/leos.1994.586942

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Progress in research on the method of P-SV wave AVO

Progress in geophysics (2003)

Sun Pengyuan Jianguo Sun LU Xiu-li

In order to utilize AVO information to inverse lithology parameters and to predict the reservoir bed effectively, the state of the art and the mainly progresses about P-SV converted-wave AVO methods are presented thoroughly in this paper. Furthermore, we review and discuss the basic assumptions and features of several classical formulas, as well as the aspects on parameter inversion for the corresponding approximation. At the same time, we also give two new approximation equations of P-SV wave reflection coefficient and discuss the methods of AVO analysis and parameters inversion by using the new formulae. It is found that the mainly purpose of each approximation is to improve the precision and to emphasize the influence of different elastic parameters, the role that each formula plays in parameter inversion. Also found is that from the relationship of elastic parameters to velocities one can transform one approximation to the others. Further, the all PP wave and P-SV wave reflection coefficients presently can be unified as power series of ray parameter. The conclusions of the present paper should be significant for AVO theory research and parameter inversion.

Reflection coefficient

Inverse transform sampling

Reflection

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Citations (3)

A 2D multistage median filter to reduce random seismic noise

Geophysics (2006)

Cai Liu Yang Liu Baojun Yang Wang Dian Jianguo Sun

Random noise lowers the S/N of seismic data and decreases the accuracy of dynamic and static corrections, thus degrading final data quality. A 2D multistage median filter (MLM) that effectively reduces the high-frequency random noise can be implemented by applying 1D median filters (MF) in several directions and choosing a value derived from them to output at the center of the 2D window. The choice of window size depends on the intensity of the random noise and the percentage of the input data samples within the window that contain noise. Synthetic data can be used to demonstrate how to choose the window size. The tendency of the method to damage the signal while reducing the noise can be minimized by optimizing window size and by applying two passes with modest-sized windows as opposed to a single pass with a larger window. Results of using the method on prestack and poststack data from the Songliao basin in China demonstrate that the method is effective at both stages.

Random noise

Sichuan basin

Intensity

10.1190/1.2236003

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Citations (62)

Multiples ray tracing using multistage group marching upwind hybrid method in regional multiscale random media with topography

Zhangqing Sun Jianguo Sun Fuxing Han Xueqiu Wang Yiteng Tian

To characterize the inhomogeneity caused by both large-scale complex geological structure and small-scale random perturbation in mountainous regions, we propose a regional multiscale method for building the random media model. Then, to compute the traveltime and ray path of different types of seismic wave in this random media model, a multistage group marching upwind hybrid method is presented. Because we use group marching method (GMM), upwind scheme, finite difference with non-uniform grid spacing and linear traveltime interpolation method together, this new ray tracing method is unconditionally stable, concise, and accurate when it is used to trace different types of seismic wave in irregular computational boundary condition caused by complex topography or interface. Finally, two examples are given for verifying the effectiveness of the above new methods. Presentation Date: Monday, September 25, 2017 Start Time: 3:55 PM Location: Exhibit Hall C, E-P Station 4 Presentation Type: EPOSTER

Fast marching method

10.1190/segam2017-17700640.1

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The Integral Method for Numerical Modeling of Acoustic Scattering on Irregular Topography

Journal of Jilin University (2007)

Jianguo Sun

According to scattering theory,irregular surface can be considered to be a special kind of perturbation.So it is available to calculate scattered field by means of scattered integral on irregular topography.In this paper,beginning with acoustic formulation in the frequency domain of threedimension,based on the theorem of Green function,we obtain the integral equation for scattered field,which is the sum form of the area integral relating to irregular topography and the volume integral relating to velocity perturbation.Following,we present the integral about the singularity of Green function.Because,numerical methods bring about the problems of calculating time and computer storage,in order to avoiding these problems,we introduce a new method: quasianalytical approximation.Based on the assumption that reflection function varies slowly in studying area,we obtain the expression of its approximation.By means of this method,the scattered field computation needs no longer to be realized by solving large linear equation systems,a numerical integration is enough.This scheme avoids the problems raised by the traditional numerical method,so that it paves way for fast forward simulation.Academic analysis indicates that this method is available in the case of small perturbation;otherwise it will cause great error.

Surface integral

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Joint 3D traveltime calculation based on fast marching method and wavefront construction

Applied Geophysics (2017)

Hui Sun Jianguo Sun Zhangqing Sun Fuxing Han Zhiqiang Liu

Fast marching method

10.1007/s11770-017-0611-3

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Inversion of Deep-Water Velocity Using the Munk Formula and the Seabed Reflection Traveltime: An Inversion Scheme That Takes the Complex Seabed Topography Into Account

IEEE Transactions on Geoscience and Remote Sensing (2023)

Peng Wu Jianguo Sun Shan Gang-yi Zhangqing Sun Puli Wei

The sound speed of seawater is not constant. It varies with season, day time, depth and range. This variation was not considered in marine seismic data processing and imaging before deep-water seismic acquisition became a routine activity. As a result, non-ignorable errors may be contained in the final migrated-image of deep-water seismic data. To eliminate such errors, we propose here a scheme for inverting the seawater velocity under the condition that the seabed has a complex topography. In this scheme, the seabed topography is represented by step grids constrained by measured water depth data, and the sound profile is assumed to be the one satisfying the Munk formula. Thus, only the parameters appearing in the Munk formula need to be inverted. This is quite different from the conventional inversion schemes that take the velocity as the inversion target. We use the conjugate gradient method to minimize the objective function given as the sum of squares of traveltime differences. Tests on synthetic common-shot data set show that our scheme presented here works as expected. Applications to real marine data set further validates the reasonability and feasibility of our scheme under complex seabed topography. To investigate the reliability of our inversion scheme, we migrate the real 2D data set using the Kirchhoff migration with the inverted Munk profile as the velocity model. The corresponding results show that the seawater velocity obtained by our inversion scheme improves the imaging quality of underwater structures.

Seabed

Synthetic data

10.1109/tgrs.2023.3279932

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Land use/cover classification of high resolution remote sensing images of mountainous areas based on texture and spectral information

Cehui kexue (2009)

Jianguo Sun

In this paper,only the shadow compensation has been done,without the topographic correction.Using the method integrating the spectral and texture features to classify land use/cover types by high-resolution remote sensing image from mountainous region.Experiment has been made and achieved a classification accuracy of 78%,indicating that the method is reasonable and practicable.

Land Cover

Texture (cosmology)

Contextual image classification

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Limited‐aperture migration

Geophysics (2000)

Jianguo Sun

I establish a general theory on the true‐amplitude migration with limited aperture. The key point of this theory is to find the true‐amplitude weight function, eliminating the contribution from the boundary of the migration aperture, or edge effect. I show that the true‐amplitude weight function is a singular generalized function defined by the migration aperture. If it is used without regularization, the singular weight function reduces a diffraction stack to the distribution of the amplitude at a given traveltime to every point along a corresponding isochron. After regularization, I obtain a formula for the true‐amplitude weight function as a weak solution having the same global properties as the fundamental solution to the governing equation derived here. In comparison with other published weight functions that disregard migration aperture, this theory contains a taper function that makes the obtained weight function suitable for the migration with limited aperture. If the migration aperture goes to infinity, my weight function reduces to the one cited in the literature. Furthermore, I present a theoretical guideline for designing both the taper function and the migration aperture. Specifically, an optimal migration aperture should be larger than or equal to the region confined by the outer boundary of the second transformed Fresnel zone. The exact size of the optimal migration aperture is obtained when an equation describing the global property of the true‐amplitude weight function is satisfied. Using the true‐amplitude weight function developed, together with a first‐order perturbation of the traveltime surfaces of point‐diffracted rays, I also obtain an asymptotic formula for the depth‐migrated image. According to the formula, diffraction stack results in frequency scaling in the depth domain. This frequency scaling gives physical insight into the problem of pulse stretching in depth migration. If the formula is expanded into a Taylor series and if the Taylor series is truncated at its linear term, the formula published in the literature can be derived. Therefore, this paper also presents a general theory on the depth‐migrated image.

Aperture (computer memory)

Weight function

Point spread function

10.1190/1.1444754

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Citations (29)

The influence of sea water velocity variation on seismic traveltimes, ray paths, and amplitude

Applied Geophysics (2012)

Fuxing Han Jianguo Sun Kun Wang

Seismic velocity

Variation (astronomy)

10.1007/s11770-012-0344-2

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Citations (17)