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基于图像自适应的降噪预处理水印新模式 被引量:1
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作者 刘伟强 须文波 《微计算机信息》 北大核心 2006年第01S期202-204,共3页
本文提出一种全新的针对几何攻击的强水印模式方案。该方案利用视觉感知模型对水印模版进行基于原图像内容的视觉掩蔽处理,然后引入低通滤波提升水印模版的抗噪和抗压缩能力。实验显示该方案具有较高的抗几何攻击能力,在应对JPEG压缩也... 本文提出一种全新的针对几何攻击的强水印模式方案。该方案利用视觉感知模型对水印模版进行基于原图像内容的视觉掩蔽处理,然后引入低通滤波提升水印模版的抗噪和抗压缩能力。实验显示该方案具有较高的抗几何攻击能力,在应对JPEG压缩也表现出了令人满意的鲁棒性。该方案适用图像的多比特信息的嵌入,也适用于二进制黑白图像的水印嵌入与检测。 展开更多
关键词 数宇水印 视觉糠知阀限 高斯白噪声 自动相关性函数
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Frequency invariability of acoustic field and passive source range estimation in shallow water 被引量:10
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作者 ZHOU ShiHong QI YuBo REN Yun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第2期225-232,共8页
The frequency invariability of the warped modal signal and the warped signal autocorrelation function in shallow water is discussed.A method is proposed for passive source-range estimation based on the frequency invar... The frequency invariability of the warped modal signal and the warped signal autocorrelation function in shallow water is discussed.A method is proposed for passive source-range estimation based on the frequency invariability and warping transform of signal autocorrelation function received by a single hydrophone in a range-independent or weak range-dependent shallow water environment.In the method,a guided source with a known range is employed to provide the crucial and relative invariant scaled features.The experimental data in shallow water with an iso-speed profile and a fluctuated thermocline are used to verify this approach.The relative errors of the source range estimation are basically less than 10%. 展开更多
关键词 frequency invariability warping transform autocorrelation function passive range estimation single hydrophone
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