A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre...A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre-stack depth migration. The successful implementation of stereotomography is highly dependent on the correct extraction of slowness components and the proper application of regularization terms. With the help of the structure tensor algorithm, a high-quality 3D stereotomography data space is achieved in a very efficient manner. Then, considering that the horizontal slowness in cross-line direction is usually unavailable for 3D narrow-azimuth data, the regularization terms must be enhanced to guarantee a stable convergence of the presented algorithm. The inverted model serves as a good model for the 3D pre-stack depth migration. The synthetic and real data examples demonstrated the robustness and effectiveness of the presented algorithm and the related schemes.展开更多
The grating eddy current displacement sensor (GECDS) for distance or position measurement used in watertight electronic calipers was described. The sensor relies on repetitive variation of inductance against displacem...The grating eddy current displacement sensor (GECDS) for distance or position measurement used in watertight electronic calipers was described. The sensor relies on repetitive variation of inductance against displacement caused by the change of coupling areas between moving coils and static reflectors. The investigations focused on setting up and utilizing a computer model of the 3D eddy current fields and geometry to analyze causes of the production of measurement blind areas, and to investigate effects of the sensor parameters, such as axial gap between coils and reflectors, reflector length and reflector width on characteristics of the sensor. Simulation results indicated that the sensor has the smallest nonlinearity error of 0.15%, which agrees well with the experimental results.展开更多
基金funded by China Natural Science Foundation(Nos.41574098 and 41630964)China key specialized project(No.2016ZX05026-001-03)
文摘A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre-stack depth migration. The successful implementation of stereotomography is highly dependent on the correct extraction of slowness components and the proper application of regularization terms. With the help of the structure tensor algorithm, a high-quality 3D stereotomography data space is achieved in a very efficient manner. Then, considering that the horizontal slowness in cross-line direction is usually unavailable for 3D narrow-azimuth data, the regularization terms must be enhanced to guarantee a stable convergence of the presented algorithm. The inverted model serves as a good model for the 3D pre-stack depth migration. The synthetic and real data examples demonstrated the robustness and effectiveness of the presented algorithm and the related schemes.
文摘The grating eddy current displacement sensor (GECDS) for distance or position measurement used in watertight electronic calipers was described. The sensor relies on repetitive variation of inductance against displacement caused by the change of coupling areas between moving coils and static reflectors. The investigations focused on setting up and utilizing a computer model of the 3D eddy current fields and geometry to analyze causes of the production of measurement blind areas, and to investigate effects of the sensor parameters, such as axial gap between coils and reflectors, reflector length and reflector width on characteristics of the sensor. Simulation results indicated that the sensor has the smallest nonlinearity error of 0.15%, which agrees well with the experimental results.
