# Changsoo Shin, Seoul KR

## Changsoo Shin, Seoul KR

Patent application number | Description | Published |
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20090006000 | Method for velocity analysis using waveform inversion in laplace domain for geophysical imaging - A Laplace transform system comprising a processor, a measured time domain wavefield, a velocity model, and Laplace damping constants, wherein the processor is programmed to calculate a substantially about zero frequency component of a Fourier transform of a time domain damped wavefield, wherein the time domain damped wavefield is damped by the Laplace damping constants to obtain long wavelength velocity information for deeper subsurface regions. | 01-01-2009 |

20100042391 | WAVEFORM INVERSION IN LAPLACE-FOURIER DOMAIN - Disclosed are an apparatus and method for visualizing subsurface velocity structure by processing signals through waveform inversion in the Laplace-Fourier domain, and a recording medium storing a program for implementing the method. A receiver receives a seismic signal from a target region, and a signal processor processes the seismic signal to generate image data for visualizing the subsurface structure of the target region. The signal processor performs the waveform inversion in the Laplace-Fourier domain, thereby obtaining a velocity model similar to an true structure of the target region. | 02-18-2010 |

20110194377 | APPARATUS AND METHOD FOR IMAGING A SUBSURFACE USING ACCUMULATED ENERGY OF WAVEFIELD - Provided is an apparatus of imaging a subsurface of a target area. The apparatus includes: an observed wavefield acquiring unit configured to acquire an observed wavefield for a target area based on seismic data; a parameter storage configured to store a characteristic parameter for the target area; a modeled wavefield creator configured to create a modeled wavefield corresponding to the observed wavefield using the characteristic parameter stored in the parameter storage; an energy calculator configured to calculate accumulated energies of the observed wavefield and the modeled wavefield, wherein the accumulated energies are defined as energies accumulated over time with respect to the observed wavefield and the modeled wavefield; and a parameter updating unit configured to update the characteristic parameter stored in the parameter storage such that a difference between the accumulated energy of the observed wavefield and the accumulated energy of the modeled wavefield is minimized. | 08-11-2011 |

20110267923 | APPARATUS AND METHOD FOR SEISMIC IMAGING USING WAVEFORM INVERSION SOLVED BY CONJUGATE GRADIENT LEAST SQUARES METHOD - Provided is an apparatus for seismic imaging by using waveform inversion in the frequency domain. The seismic imaging apparatus includes: a waveform inversion unit obtaining an equation by applying a Gauss-Newton method to an objective function consisting of residuals of logarithmic wavefields in frequency-domain waveform inversion and then obtaining a parameter vector, which minimizes the objective function, by solving the equation using a conjugate gradient method; and a subsurface structure display unit generating subsurface structure information using the parameter vector obtained by the waveform inversion unit and displaying the generated subsurface structure information. | 11-03-2011 |

20110299361 | APPARATUS AND METHOD FOR IMAGING SUBSURFACE STRUCTURE - The present invention relates to an imaging technique for modeling a subsurface structure through waveform inversion in the Laplace domain. According to the present invention, a source equivalent to the real source is calculated. The equivalent source is at least one source arranged on a virtual grid of the area to be measured, and the virtual grid has a large size which cannot be employed as the location of the real source in conventional techniques. The equivalent source has a vector obtained by multiplying an analytical solution vector and an impedance matrix of a Laplace domain wave equation, wherein said analytical solution vector is obtained from the analytical solution of a Laplace domain wave equation in a homogeneous half space by the real source. | 12-08-2011 |

20120026835 | SUBSURFACE IMAGING METHOD USING VIRTUAL SOURCES DISTRIBUTED UNIFORMLY OVER THE SUBSURFACE - There are provided a subsurface imaging apparatus and method for modeling a subsurface structure by solving a wavefield equation by waveform inversion. A virtual source that generates an observed wavefield and is distributed over grid points of the subsurface is obtained by applying a least-square method to an equation including a Green's function of the subsurface medium. Then, a subsurface model generating the observed wavefield when applying the virtual source is obtained. | 02-02-2012 |

20120236686 | SEISMIC IMAGING APPARATUS WITHOUT EDGE REFLECTIONS AND METHOD FOR THE SAME - A seismic imaging technology for imaging a subsurface structure is provided. The seismic imaging technology is applied to modeling parameters of a wave equation redefined in a new coordinate system resulting from converting space axes into a logarithmic scale. The redefined wave equation is applied to wave inversion or reverse-time migration. | 09-20-2012 |

20120243373 | SEISMIC IMAGING APPARATUS UTILIZING MACRO-VELOCITY MODEL AND METHOD FOR THE SAME - There is provided a seismic imaging technology for imaging a subsurface structure by processing measured data reflected from the subsurface structure after a wave from a source wave has been propagated to the subsurface structure. According to an aspect, there is provided a seismic imaging method for obtaining imaging data of a subsurface structure through waveform inversion using a macro-velocity model as an initial value, wherein the macro-velocity model which is used as the initial value for the waveform inversion is calculated by: calculating a velocity difference function which is a difference between a real velocity and an initial velocity model, wherein the velocity difference function is a ratio of measured seismic scattered energy and modeled scattered energy based on the initial velocity model; and calculating the macro-velocity model by updating the initial velocity model with the velocity difference function. | 09-27-2012 |

20120263016 | SEISMIC IMAGING APPARATUS - A technology of imaging a land seismic wave in the Laplace domain is provided. According to an aspect, a plurality of geophones are distributed in a lattice form at a regular interval of 150-250 m over a region to be inspected, and buried in the ground. Each of the geophones is buried in a hole excavated in the ground, and the hole is filled with cement. | 10-18-2012 |

20120323541 | SEISMIC IMAGING METHOD CONSIDERING A CONTOUR OF THE SEA BOTTOM - A seismic imaging method for imaging a subsurface structure is provided. The seismic imaging method calculates a coefficient matrix of a wave equation according to a contour of the sea bottom within a global grid. This method can be used to accurately estimate signals reflected on or transmitted through the sea bottom because it accurately reflects more detailed contours of the sea bottom within the global grid. Moreover, computational overburden is minimized. | 12-20-2012 |

20130242693 | SEISMIC IMAGING SYSTEM USING A REVERSE TIME MIGRATION ALGORITHM - Provided is seismic imaging system, particularly, reverse-time migration for generating a real subsurface image from modeling parameters calculated by waveform inversion, etc. A seismic imaging system includes: a logarithmic back-propagation unit configured to back-propagate a ration of a logarithmic measured wavefield to modeling wavefield; a virtual source estimating unit configured to estimate virtual sources from a sources; and a first convolution unit configured to convolve the back-propagated measured data with the virtual sources and to output the results of the convolution. | 09-19-2013 |

20130245954 | SEISMIC IMAGING SYSTEM USING COSINE TRANSFORM IN LOGARITHMIC AXIS - Provided is seismic imaging, particularly, a seismic imaging system. The seismic imaging system includes a measured data processing unit converting measured data from receiver to cosine transformed data in logarithmic scale axes, a subsurface structure estimating unit calculating subsurface modeling parameters with measured data transformed in the measured data processing unit based on a cosine transformed acoustic waveform equation defined along logarithmic axes, and an image output unit converting modeling parameters calculated in the subsurface structure estimating unit and outputting the converted image data. | 09-19-2013 |

20130286775 | SEISMIC IMAGING SYSTEM FOR COUSTIC-ELASTIC COUPLED MEDIA USING ACCUMULATED LAPLACE GRADIENT DIRECTION - The description relates to a seismic imaging technology technique for modeling a subsurface structure through waveform inversion in the Laplace domain. The seismic imaging system comprises a scaled gradient calculating unit calculating a scaled gradient, a modeling parameter updating unit updating the model parameters using the scaled gradient direction, and an iteration control unit controlling the scaled gradient calculating unit and the modeling parameter updating unit to repeat processing iteratively until a stopping criteria is met. | 10-31-2013 |