Seismic illumination plays an important role in subsurface imaging. A better image can be expected either through optimizing acquisition geometry or introducing more advanced seismic mi- gration and/or tomographic inv...Seismic illumination plays an important role in subsurface imaging. A better image can be expected either through optimizing acquisition geometry or introducing more advanced seismic mi- gration and/or tomographic inversion methods involving illumination compensation. Vertical cable survey is a potential replacement of traditional marine seismic survey for its flexibility and data quality. Conventional vertical cable data processing requires separation of primaries and multiples before migration. We proposed to use multi-scale full waveform inversion （FWI） to improve illumination coverage of vertical cable survey. A deep water velocity model is built to test the capability of multi-scale FWI in detecting low velocity anomalies below seabed. Synthetic results show that multi-scale FWI is an effective model building tool in deep-water exploration. Geometry optimization through target ori- ented illumination analysis and multi-scale FWI may help to mitigate the risks of vertical cable survey. The combination of multi-scale FWI, low-frequency data and multi-vertical-cable acquisition system may provide both high resolution and high fidelity subsurface models.展开更多
低截获概率(low probability of intercept,LPI)雷达作为一种具有强抗干扰能力及低截获特性的新型雷达,对其精准高效识别已成为雷达对抗一方波形识别的难点。针对该方向主流分类器卷积神经网络(convolution neural network,CNN)的结构...低截获概率(low probability of intercept,LPI)雷达作为一种具有强抗干扰能力及低截获特性的新型雷达,对其精准高效识别已成为雷达对抗一方波形识别的难点。针对该方向主流分类器卷积神经网络(convolution neural network,CNN)的结构智能寻优问题,提出一种基于粒子群优化(particle swarm optimization,PSO)算法-CNN的波形识别算法。该算法利用PSO的寻优特性,可实现较大范围内自动搭建不定层数、不定层类别及层内参数的CNN结构并进行迭代寻优;采用识别精度及网络复杂度相结合的衡量指标,可根据需求调整两者比重以实现对精度与轻量性的选择。该算法获取的CNN结构实现了比9种经典CNN结构更好的LPI雷达波形识别效果,同时避免了波形识别时人工选定CNN超参数缺乏智能性、客观性的问题,提高了选用CNN结构的适配性及高效性。展开更多
基金the financial support by the National Natural Science Foundation of China (Nos.41304109 and 41230318)the Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan) (Nos.CUG130103 and CUG110803)
文摘Seismic illumination plays an important role in subsurface imaging. A better image can be expected either through optimizing acquisition geometry or introducing more advanced seismic mi- gration and/or tomographic inversion methods involving illumination compensation. Vertical cable survey is a potential replacement of traditional marine seismic survey for its flexibility and data quality. Conventional vertical cable data processing requires separation of primaries and multiples before migration. We proposed to use multi-scale full waveform inversion （FWI） to improve illumination coverage of vertical cable survey. A deep water velocity model is built to test the capability of multi-scale FWI in detecting low velocity anomalies below seabed. Synthetic results show that multi-scale FWI is an effective model building tool in deep-water exploration. Geometry optimization through target ori- ented illumination analysis and multi-scale FWI may help to mitigate the risks of vertical cable survey. The combination of multi-scale FWI, low-frequency data and multi-vertical-cable acquisition system may provide both high resolution and high fidelity subsurface models.
文摘低截获概率(low probability of intercept,LPI)雷达作为一种具有强抗干扰能力及低截获特性的新型雷达,对其精准高效识别已成为雷达对抗一方波形识别的难点。针对该方向主流分类器卷积神经网络(convolution neural network,CNN)的结构智能寻优问题,提出一种基于粒子群优化(particle swarm optimization,PSO)算法-CNN的波形识别算法。该算法利用PSO的寻优特性,可实现较大范围内自动搭建不定层数、不定层类别及层内参数的CNN结构并进行迭代寻优;采用识别精度及网络复杂度相结合的衡量指标,可根据需求调整两者比重以实现对精度与轻量性的选择。该算法获取的CNN结构实现了比9种经典CNN结构更好的LPI雷达波形识别效果,同时避免了波形识别时人工选定CNN超参数缺乏智能性、客观性的问题,提高了选用CNN结构的适配性及高效性。
