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Composite Chaotic Pseudo-Random Sequence Encryption Algorithm for compressed video

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Tsinghua Science and Technology 2004年第2期9卷 234-241页

作者：袁春钟玉琢杨士强 Department of Computer Science and Technology Tsinghua University Beijing 100084 China

Stream cryptosystems, which implement encryption by selecting parts of the block data and header information of the compressed video stream, achieve good real-time encryption with high flexibility. Chaotic random number generator-based approaches, for example, logistics maps, are comparatively promising approachs, but are vulnerable to attacks by nonlinear dynamic forecasting. A composite chaotic cryptography scheme was developed to encrypt the compressed video with the logistics map with a Z(2311) field linear congruential algorithm to strengthen the security of the mono-chaotic cryptography. The scheme maintained real-time performance and flexibility of the chaotic sequence cryptography. The scheme also in-tegrated asymmetrical public-key cryptography and encryption and identity authentification of control pa-rameters at the initialization phase. Encryption is performed in a layered scheme based on the importance of the data in a compressed video stream. The composite chaotic cryptography scheme has the advantage that the value and updating frequency of the control parameters can be changed online to satisfy the net-work requirements and the processor capability, as well as the security requirements. Cryptanalysis shows that the scheme guarantees robust security,provides good real-time performance,and has flexible im-plementation. Statistical evaluations and tests verify that the scheme is effective.

关键词： chaotic compressed video content-based encryption digital rights management stream cryptosystem

A NOVEL ALGORITHM OF SUPER-RESOLUTION RECONSTRUCTION FOR compressed video

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Journal of Electronics(China) 2007年第3期24卷 363-368页

作者： Xu Zhongqiang Zhu Xiuchang Information Industry Ministry and Jiangsu Province Key Lab of Image Processing ＆ Image Communication Nanjing University of Posts ＆ Telecommunications Nanjing 210003 China

Super-Resolution (SR) technique means to reconstruct High-Resolution (HR) images from a sequence of Low-Resolution (LR) observations,which has been a great focus for compressed video. Based on the theory of Projection Onto Convex Set (POCS),this paper constructs Quantization Constraint Set (QCS) using the quantization information extracted from the video bit stream. By combining the statistical properties of image and the Human Visual System (HVS),a novel Adaptive Quantization Constraint Set (AQCS) is proposed. Simulation results show that AQCS-based SR al-gorithm converges at a fast rate and obtains better performance in both objective and subjective quality,which is applicable for compressed video.

关键词： Super-Resolution (SR) compressed video Projection Onto Convex Set (POCS) Quantization Constraint Set (QCS)

A NOVEL METHOD TO REALIZE compressed video SUPER-RESOLUTION RECONSTRUCTION

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Journal of Electronics(China) 2006年第2期23卷 310-313页

作者： Zhou Liang Liu Feng Zhu Xiuchang Information Industry Ministry and Jiangsu Province Key Lab of lmage Processing and Image Communication Nanjing University of Posts and Communications Nanjing 210003 China

This letter proposes a novel method of compressed video super-resolution reconstruction based on MAP-POCS (Maximum Posterior Probability-Projection Onto Convex Set). At first assuming the high-resolution model subject to Poisson-Markov distribution, then constructing the projecting convex based on MAP. According to the characteristics of compressed video, two different convexes are constructed based on integrating the inter-frame and intra-frame information in the wavelet-domain. The results of the experiment demonstrate that the new method not only outperforms the traditional algorithms on the aspects of PSNR (Peak Signal-to-Noise Ratio), MSE (Mean Square Error) and reconstruction vision effect, but also has the advantages of rapid convergence and easy extension.

关键词： Super-resolution compressed video Image reconstruction MAP-POCS

A Novel Method to Get Super-Resolution Images from Low-Resolution compressed video

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The Journal of China Universities of Posts and Telecommunications 2005年第2期12卷 50-54页

作者： ZHOU Liang ZHU Xiu-chang Information Industry Ministry and Jiangsu Province Key Lab of Image Processing and Image Communication Nanjing University of Posts and Communications Nanjing 210003 P. R. China

In order to resolve the problems of discontented restoration effect and confined applying scope which exist in the current compressed video restoration algorithms, a novel method to get super-resolution images from low-resolution compressed video is proposed in this paper. At first, a uniform model is presented and the restoration problem in the Bayesian framework is formulated under the MAP criterion, then the focus is put on the hybrid motion-compensation and transform coding schemes, at last the methods of getting the parameters are provided. The results of the simulation clearly demonstrate that our method not only has the properties of finer vision effect and wider applying scope, but also performs better than those of current classical algorithms in the aspects of Peak Signal Noise Ratio （PSNR） under the basis of the same condition.

关键词： super-resolutlon compressed video restoration

An Effective Method for Extraction of Moving Object’s Features from The compressed video

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An Effective Method for Extraction of Moving Object’s Featu...