三维视频是当前视频服务的演进趋势,采用可分级B帧(Hierarchical B Pictures,HBP)编码结构的多视点视频是三维视频的主要数据格式。针对压缩后多视点视频在无线传输中易发生数据包丢失,提出了一种面向HBP编码结构的多视点视频I帧错误隐...三维视频是当前视频服务的演进趋势,采用可分级B帧(Hierarchical B Pictures,HBP)编码结构的多视点视频是三维视频的主要数据格式。针对压缩后多视点视频在无线传输中易发生数据包丢失,提出了一种面向HBP编码结构的多视点视频I帧错误隐藏方法。隐藏过程分三大步:首先利用多视点视频编码中图片组长度短的特点,把I帧图片分成前景区和背景区;然后,对背景区丢失块采用直接拷贝法进行掩盖;最后,对前景区丢失块采用自适应方向性插值法进行错误掩盖。实验结果表明,提出的方法在主客观质量上都优于常用的I帧错误隐藏法,并有效地降低了视点间错误传递。展开更多
Bulletproof steel plates are widely used for the safety of special vehicles.This paper mainly researches on the shoot resistance of heat treated light weight B-grade bulletproof steel plates through numerical analysis...Bulletproof steel plates are widely used for the safety of special vehicles.This paper mainly researches on the shoot resistance of heat treated light weight B-grade bulletproof steel plates through numerical analysis.Based on the flow behavior of bulletproof steel plates and bullet at various high strain rates,finite element(FE) model has been set up using ANSYS/LS-DYNA software.The simulation results are compared with the shooting results,which show a good consistency and a high reliability.Therefore,the simulation results are efficient approaches and strategies to decide and select the mechanical property and thickness of bulletproof steel plates,saving a lot of work and the cost of experiments.展开更多
多视点视频编码是视频编码的研究热点之一。针对联合多视点视频编码(Joint Multi-view Video Coding,JMVC)采用的分层B帧预测结构编码复杂度高,随机访问性能较差等缺点,提出了一种改进的预测结构。所提出的预测结构对B视点中以前一帧作...多视点视频编码是视频编码的研究热点之一。针对联合多视点视频编码(Joint Multi-view Video Coding,JMVC)采用的分层B帧预测结构编码复杂度高,随机访问性能较差等缺点,提出了一种改进的预测结构。所提出的预测结构对B视点中以前一帧作为其时间参考的帧仅采用时间预测,对所有P视点的非关键帧均不进行视点间预测,有效地降低了计算复杂度,提高了随机访问性能。通过选取合适的I视点位置,以减少结构简化带来的编码效率损失。实验结果表明,与分层B帧预测结构相比,所提出的预测结构在保证编码效率损失不大的情况下,显著降低了平均编码时间。改进的预测结构也具有更好的随机访问性能。展开更多
This study focuses on the anisotropic Besov-Lions type spaces B^lp,θ（Ω;E0,E） associated with Banach spaces E0 and E. Under certain conditions, depending on l =（l1,l2,…,ln）and α=（α1,α2,…,αn）,the most regu...This study focuses on the anisotropic Besov-Lions type spaces B^lp,θ（Ω;E0,E） associated with Banach spaces E0 and E. Under certain conditions, depending on l =（l1,l2,…,ln）and α=（α1,α2,…,αn）,the most regular class of interpolation space Eα between E0 and E are found so that the mixed differential operators D^α are bounded and compact, from B^l＋s p,θ（Ω;E0,E） to B^s p,θ（Ω;Eα）.These results are applied to concrete vector-valued function spaces and to anisotropic differential-operator equations with parameters to obtain conditions that guarantee the uniform B separability with respect to these parameters. By these results the maximal B-regularity for parabolic Cauchy problem is obtained. These results are also applied to infinite systems of the quasi-elliptic partial differential equations and parabolic Cauchy problems with parameters to obtain sufficient conditions that ensure the same properties.展开更多
The latest video coding standard High Efficiency Video Coding （HEVC） can achieve much higher coding efficiency than previous video coding standards. Particularly, by exploiting the hierarchical B-picture prediction ...The latest video coding standard High Efficiency Video Coding （HEVC） can achieve much higher coding efficiency than previous video coding standards. Particularly, by exploiting the hierarchical B-picture prediction structure, temporal redundancy among neighbor frarnes is eliminated remarkably well. In practice, videos available to consumers usually contain many repeated shots, such as TV series, movies, and talk shows. According to our observations, when these videos are encoded by HEVC with the hierarchical B-picture structure, the temporal correlation in each shot is well exploited. However, the long-term correlation between repeated shots has not been used. We propose a long-term prediction （LTP） scheme to use the long-term temporal correlation between correlated shots in a video. The long-term reference （LTR） frames of a source video are chosen by clustering similar shots and extracting the representative frames, and a modified hierarchical B-picture coding structure based on an LTR frame is introduced to support long-term temporal prediction. An adaptive quantization method is further designed for LTR frames to improve the overall video coding efficiency. Experimental results show that up to 22.86% coding gain can be achieved using the new coding scheme.展开更多
文摘三维视频是当前视频服务的演进趋势,采用可分级B帧(Hierarchical B Pictures,HBP)编码结构的多视点视频是三维视频的主要数据格式。针对压缩后多视点视频在无线传输中易发生数据包丢失,提出了一种面向HBP编码结构的多视点视频I帧错误隐藏方法。隐藏过程分三大步:首先利用多视点视频编码中图片组长度短的特点,把I帧图片分成前景区和背景区;然后,对背景区丢失块采用直接拷贝法进行掩盖;最后,对前景区丢失块采用自适应方向性插值法进行错误掩盖。实验结果表明,提出的方法在主客观质量上都优于常用的I帧错误隐藏法,并有效地降低了视点间错误传递。
文摘Bulletproof steel plates are widely used for the safety of special vehicles.This paper mainly researches on the shoot resistance of heat treated light weight B-grade bulletproof steel plates through numerical analysis.Based on the flow behavior of bulletproof steel plates and bullet at various high strain rates,finite element(FE) model has been set up using ANSYS/LS-DYNA software.The simulation results are compared with the shooting results,which show a good consistency and a high reliability.Therefore,the simulation results are efficient approaches and strategies to decide and select the mechanical property and thickness of bulletproof steel plates,saving a lot of work and the cost of experiments.
文摘多视点视频编码是视频编码的研究热点之一。针对联合多视点视频编码(Joint Multi-view Video Coding,JMVC)采用的分层B帧预测结构编码复杂度高,随机访问性能较差等缺点,提出了一种改进的预测结构。所提出的预测结构对B视点中以前一帧作为其时间参考的帧仅采用时间预测,对所有P视点的非关键帧均不进行视点间预测,有效地降低了计算复杂度,提高了随机访问性能。通过选取合适的I视点位置,以减少结构简化带来的编码效率损失。实验结果表明,与分层B帧预测结构相比,所提出的预测结构在保证编码效率损失不大的情况下,显著降低了平均编码时间。改进的预测结构也具有更好的随机访问性能。
文摘This study focuses on the anisotropic Besov-Lions type spaces B^lp,θ（Ω;E0,E） associated with Banach spaces E0 and E. Under certain conditions, depending on l =（l1,l2,…,ln）and α=（α1,α2,…,αn）,the most regular class of interpolation space Eα between E0 and E are found so that the mixed differential operators D^α are bounded and compact, from B^l＋s p,θ（Ω;E0,E） to B^s p,θ（Ω;Eα）.These results are applied to concrete vector-valued function spaces and to anisotropic differential-operator equations with parameters to obtain conditions that guarantee the uniform B separability with respect to these parameters. By these results the maximal B-regularity for parabolic Cauchy problem is obtained. These results are also applied to infinite systems of the quasi-elliptic partial differential equations and parabolic Cauchy problems with parameters to obtain sufficient conditions that ensure the same properties.
基金Project supported by the National Natural Science Foundation of China(No.61371162)
文摘The latest video coding standard High Efficiency Video Coding （HEVC） can achieve much higher coding efficiency than previous video coding standards. Particularly, by exploiting the hierarchical B-picture prediction structure, temporal redundancy among neighbor frarnes is eliminated remarkably well. In practice, videos available to consumers usually contain many repeated shots, such as TV series, movies, and talk shows. According to our observations, when these videos are encoded by HEVC with the hierarchical B-picture structure, the temporal correlation in each shot is well exploited. However, the long-term correlation between repeated shots has not been used. We propose a long-term prediction （LTP） scheme to use the long-term temporal correlation between correlated shots in a video. The long-term reference （LTR） frames of a source video are chosen by clustering similar shots and extracting the representative frames, and a modified hierarchical B-picture coding structure based on an LTR frame is introduced to support long-term temporal prediction. An adaptive quantization method is further designed for LTR frames to improve the overall video coding efficiency. Experimental results show that up to 22.86% coding gain can be achieved using the new coding scheme.
