The filter operator used in normal multichannel matching filter is physically realizable.This filter operator only delays seismic data in the filtering process.A noncausal multichannel matching filter based on a least...The filter operator used in normal multichannel matching filter is physically realizable.This filter operator only delays seismic data in the filtering process.A noncausal multichannel matching filter based on a least squares criterion is proposed to resolve the problem in which predicted multiple model data is Iater than real data.The diferences between causal and noncausal multichannel matching filters are compared using a synthetic shot gather,which demonstrates the validity of the noncausal matching filter.In addition,a variable length sliding window which changes with ofset and layer velocity is proposed to solve the count of events increasing with increasing ofset in a fixed Iength sliding window.This variable length sliding window is also introduced into the modified and expanded multichannel matching filter.This method is applied to the Pluto1.5 synthetic data set.The benefits of the non.causal filter operator and variable length sliding window are demonstrated bv the good multiple attenuation result.展开更多
Reversible watermarking technique enables to extract embedded information without any loss of the host signal. For the reduction of the embedding distortion, a desirable reversible watermarking approach should exploit...Reversible watermarking technique enables to extract embedded information without any loss of the host signal. For the reduction of the embedding distortion, a desirable reversible watermarking approach should exploit efficient prediction way to generate prediction errors with a smaller magnitude for expansion embedding. In this paper, we present a reversible audio watermarking scheme based on a new non-causal prediction method and embedding strategy. The proposed non-causal prediction method provides non-integer prediction errors and the proposed expansion embedding strategy can proceed them for a lower embedding distortion. Experimental results have shown that the proposed reversible technique has a lower embedding distortion for the same embedding payload in comparison with the existing state-of-the-art works.展开更多
In this paper, using the Guichardet space technique, the relationship between Fermion quantum stochastic calculus and non-causal calculus in Segal space L^2(H) is discussed, and an anticipating quantum stochastic calc...In this paper, using the Guichardet space technique, the relationship between Fermion quantum stochastic calculus and non-causal calculus in Segal space L^2(H) is discussed, and an anticipating quantum stochastic calculus is naturally given.展开更多
目的 图像复原是计算机视觉领域的经典研究问题。选择性状态空间模型(selective state space model,selective SSM)因其高效的序列建模能力,广泛应用于各类图像复原任务。另外,非局部图像块之间存在依赖关系,能够辅助提升复原性能。而传...目的 图像复原是计算机视觉领域的经典研究问题。选择性状态空间模型(selective state space model,selective SSM)因其高效的序列建模能力,广泛应用于各类图像复原任务。另外,非局部图像块之间存在依赖关系,能够辅助提升复原性能。而传统SSM采用确定性的令牌(token)扫描方式,仅能提取令牌序列的单向依赖关系。此时,令牌间的关系建模因在序列中的先后顺序受到因果性制约,这与图像块之间的非因果相互关系形成冲突,限制了复原性能的进一步提升。针对此问题,提出一种面向图像复原的非因果选择性状态空间模型,旨在赋予SSM建模令牌之间非因果依赖关系的能力。方法 为解决SSM在因果性建模与图像内容非因果关系之间的矛盾,提出随机扫描策略,突破了传统扫描方式在因果性和空间限制上的局限,实现了令牌序列之间的非因果建模。具体而言,构建了随机重排和逆重排函数,实现了非固定次序下的令牌扫描,有效建模了不同令牌之间的非因果依赖关系。此外,针对图像退化干扰存在空间尺度变化和形态结构复杂的特点,融合多尺度先验构建了具有局部与全局信息互补性的非因果Mamba模型(non-causal Mamba,NCMamba),实现了对于各类图像复原任务的有效适配。结果 实验分别在图像去噪、去模糊和去阴影任务上进行,验证了所提非因果建模和局部—全局互补策略的有效性。与现有方法相比,所提模型在图像去阴影数据集SRD(shadow removal dataset)上的峰值信噪比提升0.86 dB。结论 面向图像复原任务,构建了非因果选择性状态空间模型,建模了令牌之间的非因果依赖关系,实现了局部与全局信息的有效互补,显著提升了复原性能。所提方法在主客观评价指标上均取得优异性能,为图像复原领域提供了新的解决方案。展开更多
针对无源雷达信号处理中分数延迟直达波及多径杂波不能被完全对消的问题,提出了一种非因果的归一化最小均方(normalized least mean square,NLMS)自适应对消算法。根据采样信号的插值理论,推导出了分数延迟直达波相对于参考信号具有非...针对无源雷达信号处理中分数延迟直达波及多径杂波不能被完全对消的问题,提出了一种非因果的归一化最小均方(normalized least mean square,NLMS)自适应对消算法。根据采样信号的插值理论,推导出了分数延迟直达波相对于参考信号具有非因果系统响应的特点,然后在传统NLMS对消器的基础上,通过增加部分非因果的滤波网络同时实现了最小均方误差(least mean square error,LMSE)准则下的自适应插值和杂波抑制。经过计算机仿真及实测数据验证,该算法相较于目前已有方法能够降低计算复杂度,并在相同条件下获得更高的杂波相消比。展开更多
基金supported by the National 863 Program (Grant No. 2006AA09A102-09)the National 973 Program (GrantNo. 2007CB209606)
文摘The filter operator used in normal multichannel matching filter is physically realizable.This filter operator only delays seismic data in the filtering process.A noncausal multichannel matching filter based on a least squares criterion is proposed to resolve the problem in which predicted multiple model data is Iater than real data.The diferences between causal and noncausal multichannel matching filters are compared using a synthetic shot gather,which demonstrates the validity of the noncausal matching filter.In addition,a variable length sliding window which changes with ofset and layer velocity is proposed to solve the count of events increasing with increasing ofset in a fixed Iength sliding window.This variable length sliding window is also introduced into the modified and expanded multichannel matching filter.This method is applied to the Pluto1.5 synthetic data set.The benefits of the non.causal filter operator and variable length sliding window are demonstrated bv the good multiple attenuation result.
基金Supported by the National Natural Science Foundation of China (61272414the Science and Technology Project of Guangzhou Province(2012J4100108)the Jinan University Outstanding Postgraduate Research and Innovation Program, Jinan University Outstanding Undergraduate Scientific Research Innovation Cultivation Project
文摘Reversible watermarking technique enables to extract embedded information without any loss of the host signal. For the reduction of the embedding distortion, a desirable reversible watermarking approach should exploit efficient prediction way to generate prediction errors with a smaller magnitude for expansion embedding. In this paper, we present a reversible audio watermarking scheme based on a new non-causal prediction method and embedding strategy. The proposed non-causal prediction method provides non-integer prediction errors and the proposed expansion embedding strategy can proceed them for a lower embedding distortion. Experimental results have shown that the proposed reversible technique has a lower embedding distortion for the same embedding payload in comparison with the existing state-of-the-art works.
文摘In this paper, using the Guichardet space technique, the relationship between Fermion quantum stochastic calculus and non-causal calculus in Segal space L^2(H) is discussed, and an anticipating quantum stochastic calculus is naturally given.
文摘针对无源雷达信号处理中分数延迟直达波及多径杂波不能被完全对消的问题,提出了一种非因果的归一化最小均方(normalized least mean square,NLMS)自适应对消算法。根据采样信号的插值理论,推导出了分数延迟直达波相对于参考信号具有非因果系统响应的特点,然后在传统NLMS对消器的基础上,通过增加部分非因果的滤波网络同时实现了最小均方误差(least mean square error,LMSE)准则下的自适应插值和杂波抑制。经过计算机仿真及实测数据验证,该算法相较于目前已有方法能够降低计算复杂度,并在相同条件下获得更高的杂波相消比。
