基于H.264/AVC的自适应视频错误隐藏技术算法

针对帧内错误隐藏,研究了基于边缘检测的错误隐藏算法,提出了根据丢失块特点自适应的选择基于边缘检测错误隐藏算法或H.264的空间像素加权平均算法。通过在MATLAB平台上对几种视频错误隐藏算法进行仿真测试,结果表明这种自适应的视频错误隐藏算法在主客观效果上都有所提高。     

基于区域划分的立体视频整帧丢失错误隐藏新算法

针对立体视频传输中右视点整帧丢失,提出了一种基于区域划分的立体视频整帧丢失错误隐藏新算法。首先通过丢失帧视点内和视点间相邻帧的运动信息,估计丢失帧的运动区域与静止区域;然后利用视点间的全局视差,将丢失帧运动区域进一步划分为遮挡边界区域和非遮挡边界区域,并对遮挡边界区域和非遮挡边界区域分别采用运动补偿预测和视差补偿预测进行恢复,而对静止区域则直接采用帧拷贝的方法恢复丢失信息。实验结果表明,本文算法有效提高了所恢复的立体视频丢失帧图像的主客观质量。     

基于改进遗传算法的潜艇隐蔽航路规划

基于改进遗传算法的潜艇隐蔽航路规划,采用栅格法对规划环境进行离散化,提取原始海图数据.根据先验知识设计遗传算法初始群体产生方式和适应度函数.并以MapX控件为图形平台,在Delphi环境下进行了仿真试验.仿真结果表明,改进的潜艇隐蔽航路规划方法提高了规划效率,能够得到较好的规划结果.     

新的自适应MRF-MAP视频序列误差掩盖

编码数字视频序列经过受噪声影响的信道传输后通常会出现的图像信息丢失.本文提出一种新的基于马尔可夫随机场－最大后验估计(MRF-MAP)的自适应误差掩盖方法,作为在解码器端的后处理工具去解决这种问题.以往的MRF-MAP方法通常会因为迭代造成边缘被模糊,因为初始解不准确而造成块效应.为了保护边缘,本文利用了判别分析法引入像素隶属度,针对像素所处的边缘或平滑区域,自适应确定MRF的Huber函数中边缘阈值T.同时又在Huber函数的线性部分引入斜率k,以消除块效应.仿真结果表明,本文提出的方法无论在主观视觉评价,还是在客观的数值标准下,都能比现存的误差掩盖方法恢复出质量更好的图像.     

A Derivative Matrix-Based Covert Communication Method in Blockchain

The data in the blockchain cannot be tampered with and the users are anonymous, which enables the blockchain to be a natural carrier for covert communication. However, the existing methods of covert communication in blockchain suffer from the predefined channel structure, the capacity of a single transaction is not high, and the fixed transaction behaviors will lower the concealment of the communication channel. Therefore, this paper proposes a derivation matrix-based covert communication method in blockchain. It uses dual-key to derive two types of blockchain addresses and then constructs an address matrix by dividing addresses into multiple layers to make full use of the redundancy of addresses. Subsequently, to solve the problem of the lack of concealment caused by the fixed transaction behaviors, divide the rectangular matrix into square blocks with overlapping regions and then encrypt different blocks sequentially to make the transaction behaviors of the channel addresses match better with those of the real addresses. Further, the linear congruence algorithm is used to generate random sequence, which provides a random order for blocks encryption, and thus enhances the security of the encryption algorithm. Experimental results show that this method can effectively reduce the abnormal transaction behaviors of addresses while ensuring the channel transmission efficiency.