In this paper,an effective intra prediction mode-based video strganography is proposed.Secret messages are embedded during the intra prediction of the video encoding without causing large embedding impact.The influenc...In this paper,an effective intra prediction mode-based video strganography is proposed.Secret messages are embedded during the intra prediction of the video encoding without causing large embedding impact.The influence on the sum of absolute difference(SAD)in intra prediction modes(IPMs)reversion phenomenon is sharp when modifying IPMs.It inspires us to take the SAD prediction deviation(SPD)to define the distortion function.What is more,the mapping rule between IPMs and the codewords is introduced to further reduce the SPD values of each intra block.Syndrome-trellis code(STC)is used as the practical embedding implementation.Experimental results demonstrate that our proposed steganographic scheme presents high undetectability compared with existing IPMs-based steganographic approaches.It also outperforms these schemes on stego video quality.展开更多
多功能视频编码(versatile video coding,VVC)作为最新一代的视频编码标准,通过引入多种高效的编码工具进一步提升了视频编码性能。然而,VVC标准引入了四叉树加多类型树(quadtree plus multi-type tree,QTMT)划分结构,并将帧内预测模式...多功能视频编码(versatile video coding,VVC)作为最新一代的视频编码标准,通过引入多种高效的编码工具进一步提升了视频编码性能。然而,VVC标准引入了四叉树加多类型树(quadtree plus multi-type tree,QTMT)划分结构,并将帧内预测模式从35种扩展到67种,导致编码复杂度急剧上升。为降低VVC的帧内编码复杂度,首先,提出了一种基于图神经网络的帧内编码单元(coding unit,CU)划分快速算法,该算法利用高效的图神经网络模型直接预测CU的最优划分模式,从而跳过冗余的CU划分遍历。其次,提出了一种基于空间相关性和纹理特征的帧内模式选择快速算法,该算法利用平均方向方差和Sobel梯度算子确定纹理方向,并跳过部分角度预测模式,同时结合预测模式间的相关性精简率失真模式列表。实验结果表明,该算法能够在BDBR(bjontegaard delta bit rate)上升2.29%的代价下,节省64.04%的编码时间。展开更多
In order to reduce the encoding complexity of macroblock coding mode decision in H.264/AVC, a selective smaller block-size searching algorithm and a selective intra coding mode searching algorithm are proposed by usin...In order to reduce the encoding complexity of macroblock coding mode decision in H.264/AVC, a selective smaller block-size searching algorithm and a selective intra coding mode searching algorithm are proposed by using the high correlation among coding modes and in spatial and temporal domains of video sequence. Simulation results demonstrate that the proposed algorithm can provide significant improvement in computational requirement, with negligible small picture quality degradation and slight bit rate increase.展开更多
Under harmonic wave excitation, the dynamic response of a bilinear SDOF system can be expressed by the Hilbert spectrum. The Hilbert spectrum can be formulated by (1) the inter-wave combination mechanism between the s...Under harmonic wave excitation, the dynamic response of a bilinear SDOF system can be expressed by the Hilbert spectrum. The Hilbert spectrum can be formulated by (1) the inter-wave combination mechanism between the steady response and the transient response when the system behaves linearly, or (2) the intra-wave modulation mechanism embedded in one intrinsic mode function (IMF) component when the system behaves nonlinearly. The temporal variation of the instantaneous frequency of the IMF component is consistent with the system nonlinear behavior of yielding and unloading. As a thorough study of this fundamental structural dynamics problem, this article investigates the influence of the amplitude of the harmonic wave excitation on the Hilbert spectrum and the intrinsic oscillatory mode of the dynamic response of a bilinear SDOF system.展开更多
本文设计制作了一款阵列规模为1024×1024元、像元尺寸为10μm×10μm的昼夜兼容成像EMCCD(electron multiplying charge coupled device),该器件包含国内首次制作的浮置栅放大器,该放大器电荷转换因子(Charge to voltage facto...本文设计制作了一款阵列规模为1024×1024元、像元尺寸为10μm×10μm的昼夜兼容成像EMCCD(electron multiplying charge coupled device),该器件包含国内首次制作的浮置栅放大器,该放大器电荷转换因子(Charge to voltage factor,CVF)为3.57μV/e^(-),满阱55 ke^(-),能够非破坏性判断信号强度。该功能使得场景中微光照区域的像素可以选择性地路由至倍增通道输出,而强光照区域的像素会路由至非倍增通道输出,有了这种场景内可切换增益特性,两种输出的信号重新组合,实现高动态成像。同时为了实现器件在强光应用场合的抗光晕功能,器件像元区域采用了纵向抗晕设计,抗晕倍数为200倍,基于此类器件制作的相机能够恰当地在暗视场中呈现明亮的图像。展开更多
基金This work was supported by National Key R&D Plan of China(Grant No.2017YFB0802203)National Natural Science Foundation of China(Grant No.U173620045,61732021,61472165 and 61373158)+4 种基金Natural Science Foundation of Guangdong Province,China(Grant No.2017A030313390)Science and Technology Program of Guangzhou,China(Grant No.201804010428)Guangdong Provincial Engineering Technology Research Center on Network Security Detection and Defence(Grant No.2014B090904067)Guangdong Provincial Special Funds for Applied Technology Research and Development and Transformation of Important Scientific and Technological Achieve(Grant No.2016B010124009)the Zhuhai Top Discipline-Information Security,Guangzhou Key Laboratory of Data Security and Privacy Preserving,Guangdong Key Laboratory of Data Security and Privacy Preserving,the Fundamental Research Funds for the Central Universities.
文摘In this paper,an effective intra prediction mode-based video strganography is proposed.Secret messages are embedded during the intra prediction of the video encoding without causing large embedding impact.The influence on the sum of absolute difference(SAD)in intra prediction modes(IPMs)reversion phenomenon is sharp when modifying IPMs.It inspires us to take the SAD prediction deviation(SPD)to define the distortion function.What is more,the mapping rule between IPMs and the codewords is introduced to further reduce the SPD values of each intra block.Syndrome-trellis code(STC)is used as the practical embedding implementation.Experimental results demonstrate that our proposed steganographic scheme presents high undetectability compared with existing IPMs-based steganographic approaches.It also outperforms these schemes on stego video quality.
文摘多功能视频编码(versatile video coding,VVC)作为最新一代的视频编码标准,通过引入多种高效的编码工具进一步提升了视频编码性能。然而,VVC标准引入了四叉树加多类型树(quadtree plus multi-type tree,QTMT)划分结构,并将帧内预测模式从35种扩展到67种,导致编码复杂度急剧上升。为降低VVC的帧内编码复杂度,首先,提出了一种基于图神经网络的帧内编码单元(coding unit,CU)划分快速算法,该算法利用高效的图神经网络模型直接预测CU的最优划分模式,从而跳过冗余的CU划分遍历。其次,提出了一种基于空间相关性和纹理特征的帧内模式选择快速算法,该算法利用平均方向方差和Sobel梯度算子确定纹理方向,并跳过部分角度预测模式,同时结合预测模式间的相关性精简率失真模式列表。实验结果表明,该算法能够在BDBR(bjontegaard delta bit rate)上升2.29%的代价下,节省64.04%的编码时间。
基金National Natural Science Foundation of China (60372018)
文摘In order to reduce the encoding complexity of macroblock coding mode decision in H.264/AVC, a selective smaller block-size searching algorithm and a selective intra coding mode searching algorithm are proposed by using the high correlation among coding modes and in spatial and temporal domains of video sequence. Simulation results demonstrate that the proposed algorithm can provide significant improvement in computational requirement, with negligible small picture quality degradation and slight bit rate increase.
基金National Natural Science Foundation of China Under Grant No.50278090
文摘Under harmonic wave excitation, the dynamic response of a bilinear SDOF system can be expressed by the Hilbert spectrum. The Hilbert spectrum can be formulated by (1) the inter-wave combination mechanism between the steady response and the transient response when the system behaves linearly, or (2) the intra-wave modulation mechanism embedded in one intrinsic mode function (IMF) component when the system behaves nonlinearly. The temporal variation of the instantaneous frequency of the IMF component is consistent with the system nonlinear behavior of yielding and unloading. As a thorough study of this fundamental structural dynamics problem, this article investigates the influence of the amplitude of the harmonic wave excitation on the Hilbert spectrum and the intrinsic oscillatory mode of the dynamic response of a bilinear SDOF system.
文摘本文设计制作了一款阵列规模为1024×1024元、像元尺寸为10μm×10μm的昼夜兼容成像EMCCD(electron multiplying charge coupled device),该器件包含国内首次制作的浮置栅放大器,该放大器电荷转换因子(Charge to voltage factor,CVF)为3.57μV/e^(-),满阱55 ke^(-),能够非破坏性判断信号强度。该功能使得场景中微光照区域的像素可以选择性地路由至倍增通道输出,而强光照区域的像素会路由至非倍增通道输出,有了这种场景内可切换增益特性,两种输出的信号重新组合,实现高动态成像。同时为了实现器件在强光应用场合的抗光晕功能,器件像元区域采用了纵向抗晕设计,抗晕倍数为200倍,基于此类器件制作的相机能够恰当地在暗视场中呈现明亮的图像。
