Nowadays the side-looking SAR echo data can be obtained easily from the commercial channel, while that of other SAR imaging modes such as squint, spotlight are difficult to be acquired. This paper presents a new schem...Nowadays the side-looking SAR echo data can be obtained easily from the commercial channel, while that of other SAR imaging modes such as squint, spotlight are difficult to be acquired. This paper presents a new scheme to transform the side-looking returns to squint ones, in a direct and an indirect approach respectively. Direct transformation uses the data with a wide azimuth beam angle. The maximum of the required squint angle is limited under several degrees. Squint data under indirect transformation can be obtained by adding a platform velocity along slant range according to the required squint angles. Then the squint data is determined by the angle between the new forward velocity and line-of-sight direction. This method results in higher squint angle compared with the first one. Verification shows the feasibility of these approaches with illustration of side-looking E-SAR raw data processing. The future work will be on the precise Doppler centroid estimation and effective imaging algorithm development.展开更多
Wide-angle echo data of submarine sedimentary beds are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler. Usually the wide-angle echo data are processed with comm...Wide-angle echo data of submarine sedimentary beds are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler. Usually the wide-angle echo data are processed with common-depth-point stack method to obtain the stacked section for gcological interpretation. When the acoustic velocity of the sedimentary layers has a lateral variation, the stacked section does not represent the real structure of sedimentary layers. Based on this stacked section, we would probably draw a false conclusion.In case of knowing the acoustic velocity of sedimentary beds, we may remove the distortions caused by acoustic velocity lateral variations from the stacked section with acoustie wave equation Kirchhoff integration which continues the wave fields in downgoing and upgoing directions respectively. Thus the accurate image of the structure of submarine sedimentary layers is obtained.展开更多
Imaging sea-bed sediment layers from echo data, which are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler, is a way to reconstruct the structure of sedimeat lay...Imaging sea-bed sediment layers from echo data, which are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler, is a way to reconstruct the structure of sedimeat layers with acoustic wav equation. The equation which describes the wave propagation is used for backward extrapolation of echo data observed at sea surface. When the medium is homogeneous or horizontally layered, time imaging approach is valid. However, in the case where a considerable lateral variation in velocity exists, the image section processed with the time approach does not represent the real structure, because of distortions caused by thin-lens effect similar as in optics. In this case, depth imaging approach must be used for both the time-shift correction of refraction terms and the convergence of diffractions simultaneously as wavefields are downward continued. As a result, the good image can be derived to determine the structure of sea-bed sediment layers.展开更多
The recording and playback of information using a reverse stimulated photon—echo hologram when exposed to the recording medium pulse of non-resonant electromagnetic standing wave was considered. It was shown that the...The recording and playback of information using a reverse stimulated photon—echo hologram when exposed to the recording medium pulse of non-resonant electromagnetic standing wave was considered. It was shown that the spatial intensity distribution in stimulated echo hologram response depended on the electric field intensity of non-resonant standing wave that allowed controlling by a reproducible image.展开更多
氧化亚铁(FeO)含量是衡量烧结矿强度和还原性的重要指标,烧结过程FeO含量的实时准确预测对于提升烧结质量、优化烧结工艺具有重要意义.然而烧结过程热状态参数缺失、过程参数波动频繁给FeO含量的高精度预测带来巨大的挑战,为此,提出一...氧化亚铁(FeO)含量是衡量烧结矿强度和还原性的重要指标,烧结过程FeO含量的实时准确预测对于提升烧结质量、优化烧结工艺具有重要意义.然而烧结过程热状态参数缺失、过程参数波动频繁给FeO含量的高精度预测带来巨大的挑战,为此,提出一种基于知识与变权重回声状态网络融合(Fusion of data-knowledge and adaptive weight echo state network, DK-AWESN)的烧结过程FeO含量预测方法.首先,针对烧结过程热状态参数缺失的问题,建立烧结料层最高温度分布模型,实现基于料层温度分布特征的FeO含量等级划分;其次,针对烧结过程参数波动频繁的问题,提出基于核函数高维映射的多尺度数据配准方法,有效抑制离群点的影响,提升建模数据的质量;最后,针对烧结过程数据驱动模型缺乏机理认知致使模型预测精度不高的问题,将过程数据中提取得到的FeO含量等级知识与AW-ESN (Adaptive weight echo state network)结合,建立DK-AWESN模型,有效提升复杂工况下FeO含量的预测精度.现场工业数据试验表明,所提方法能实时准确地预测烧结过程FeO含量,为烧结过程的智能化调控提供实时有效的FeO含量反馈信息.展开更多
文摘Nowadays the side-looking SAR echo data can be obtained easily from the commercial channel, while that of other SAR imaging modes such as squint, spotlight are difficult to be acquired. This paper presents a new scheme to transform the side-looking returns to squint ones, in a direct and an indirect approach respectively. Direct transformation uses the data with a wide azimuth beam angle. The maximum of the required squint angle is limited under several degrees. Squint data under indirect transformation can be obtained by adding a platform velocity along slant range according to the required squint angles. Then the squint data is determined by the angle between the new forward velocity and line-of-sight direction. This method results in higher squint angle compared with the first one. Verification shows the feasibility of these approaches with illustration of side-looking E-SAR raw data processing. The future work will be on the precise Doppler centroid estimation and effective imaging algorithm development.
文摘Wide-angle echo data of submarine sedimentary beds are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler. Usually the wide-angle echo data are processed with common-depth-point stack method to obtain the stacked section for gcological interpretation. When the acoustic velocity of the sedimentary layers has a lateral variation, the stacked section does not represent the real structure of sedimentary layers. Based on this stacked section, we would probably draw a false conclusion.In case of knowing the acoustic velocity of sedimentary beds, we may remove the distortions caused by acoustic velocity lateral variations from the stacked section with acoustie wave equation Kirchhoff integration which continues the wave fields in downgoing and upgoing directions respectively. Thus the accurate image of the structure of submarine sedimentary layers is obtained.
文摘Imaging sea-bed sediment layers from echo data, which are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler, is a way to reconstruct the structure of sedimeat layers with acoustic wav equation. The equation which describes the wave propagation is used for backward extrapolation of echo data observed at sea surface. When the medium is homogeneous or horizontally layered, time imaging approach is valid. However, in the case where a considerable lateral variation in velocity exists, the image section processed with the time approach does not represent the real structure, because of distortions caused by thin-lens effect similar as in optics. In this case, depth imaging approach must be used for both the time-shift correction of refraction terms and the convergence of diffractions simultaneously as wavefields are downward continued. As a result, the good image can be derived to determine the structure of sea-bed sediment layers.
文摘The recording and playback of information using a reverse stimulated photon—echo hologram when exposed to the recording medium pulse of non-resonant electromagnetic standing wave was considered. It was shown that the spatial intensity distribution in stimulated echo hologram response depended on the electric field intensity of non-resonant standing wave that allowed controlling by a reproducible image.
文摘氧化亚铁(FeO)含量是衡量烧结矿强度和还原性的重要指标,烧结过程FeO含量的实时准确预测对于提升烧结质量、优化烧结工艺具有重要意义.然而烧结过程热状态参数缺失、过程参数波动频繁给FeO含量的高精度预测带来巨大的挑战,为此,提出一种基于知识与变权重回声状态网络融合(Fusion of data-knowledge and adaptive weight echo state network, DK-AWESN)的烧结过程FeO含量预测方法.首先,针对烧结过程热状态参数缺失的问题,建立烧结料层最高温度分布模型,实现基于料层温度分布特征的FeO含量等级划分;其次,针对烧结过程参数波动频繁的问题,提出基于核函数高维映射的多尺度数据配准方法,有效抑制离群点的影响,提升建模数据的质量;最后,针对烧结过程数据驱动模型缺乏机理认知致使模型预测精度不高的问题,将过程数据中提取得到的FeO含量等级知识与AW-ESN (Adaptive weight echo state network)结合,建立DK-AWESN模型,有效提升复杂工况下FeO含量的预测精度.现场工业数据试验表明,所提方法能实时准确地预测烧结过程FeO含量,为烧结过程的智能化调控提供实时有效的FeO含量反馈信息.
