视频监控技术在水利信息化中的应用

水利信息化是实现水利现代化的重要手段,视频监控技术在水利信息化建设中发挥着重要的作用。本文首先研究了视频监控中的视频数据采集、编码、传输,以及分析技术,然后阐述了视频监控在水利中的应用。     

基于SMTP或者C#类发送邮件原理及其实现

强大的．NET平台对编写邮件程序提供了有力的支持。该文总结了在c#环境下,基于底层的SMTP（ESMPT）协议和MIME协议发送电子邮件,以及使用MailMessage类创建并发送邮件的过程,并重点解析了身份认证,邮件编码以及发送邮件附件等关键实用技术,然后给出了实现代码。     

Viterbi改进算法研究

Viterbi译码算法是最大似然译码。论文所研究的改进Viterbi算法,不但保持了原有Viterbi算法的特性,而且在减少译码路径的情况下,能较好地解决突发错误信道中,原Viterbi译码算法则性能急剧下降的问题。通过在编码信道模型上的仿真表明,已知正确的约束位越多,分布的越密,则提高的性能越明显。     

一种面向H.264/AVC的运动估计算法

提出了一种使用具有方向偏向性搜索模板和基于预测模式自适应选择运动估计方案的EPZS(enhanced predictive zonal search)改进算法。该算法将运动估计过程与H.264/AVC中多参考帧、多预测模式等编码工具紧密结合,充分利用视频中运动具有高度时空相关性的特点,综合考虑速度、图像质量及压缩效率等方面的性能。实验结果表明,该算法以极小的计算量得到了与全搜索方法接近的效果;与EPZS算法相比,运动估计的处理速度有了较大幅度的提高,同时保持了与之相当、有时甚至更优的率失真性能。此外,该算法具有很好的鲁棒性,并且能够产生平滑的运动矢量场。     

AVS视频解码的错误检测与掩盖方法

研究了视频误码的语法/语义检测、相关性检测方法和错误掩盖方法,分析了AVS的技术特性。在此基础上提出了一种基于AVS的错误两步检测法和基于图像编码帧类型(I,P,B)的自适应错误掩盖方法。实验结果表明,两步检测法能对AVS码流中的错误进行准确定位,自适应错误掩盖方法对图像的恢复效果显著。同时该方法不中断解码器,不影响解码器的实时解码速度。     

基于H.264编码模式的快速判决算法

H.264在运动估计中引入了多种不同的编码模式,使得模式选择过程异常复杂。针对这一问题,本文提出了一个新概念——编码模式参考集,并给出了一种基于区域预测的编码模式参考集选择方法。该方法可以大大减少候选参考模式的数目,简化模式选择过程。并根据所选模式的特点给出了一种基于模式选择的自适应搜索策略。实验结果表明,本文提出的新算法在重建图像质量没有明显下降的前提下,编码速度有了显著提高。     

一个足球机器人视频跟踪算法

随着机器人和人工智能技术的发展,在复杂环境中特别是足球机器人的实时比赛的环境进行识别和跟踪已是一个挑战性的课题,提出了一个基于投影的目标跟踪算法,该算法首先把比赛场地分成了若干区域,在这些区域内搜索一个种子点,然后以此点为起点沿垂直或水平方向在目标区域搜索,计算该点的投影值,根据这些投影值识别出目标的一个顶点(或小球的球心),进而识别出目标;最后,提取出7个运动目标的位置和方向,实验结果表明,该算法与其他方法相比有计算量少、图像处理速度快和易于实现等优点。同时,该算法在仿真系统中得到了检验。     

一种结合矩阵相关系数的快速分形图像编码

分形编码是一种非常有潜力的压象压缩技术,但其算法过程耗时较长和计算复杂性过高,因此需要一种减少编码时间的方法.针对此问题,根据分形图像编码的特点,首先利用分形后定义域和值域之间的相关系数的大小来确定最佳的定义域块,提出了旨在降低编码复杂度和缩短编码时间的一种改进的快速分形编码算法.算法在编码搜索过程中,仅搜索符合条件的父块,从而减少搜索范围,降低编码时间.实验结果表明,算法与基本分形算法比较,在峰值信噪比和图像质量可以接受的情况下,使编码速度大大加快.     

GPU-accelerated DXT and JPEG compression schemes for low-latency network transmissions of HD, 2K,and 4K video

Low-latency transmissions of high resolution video such as HD, 2K, or 4K over both Internet and private IP networks have found a foothold in many interactive applications, ranging from collaborative environments in science and medicine to the arts and entertainment industry. In this paper we demonstrate how the power of commodity graphics processing units can be used for efficient implementation of JPEG and DXT compression. We propose an approach to fine-grained parallelization of JPEG compression and the use of auxiliary indexes for efficient decompression, which are backward compatible with the JPEG standard. In-depth performance analysis is provided to show various aspects of the proposed parallelization including the dependency on image content and on various settings of the compression algorithm, as well as the impact of compression for interactive applications in terms of end-to-end latency. The applicability of these compression schemes in medicine and cinematography has also been evaluated using double-blind ABX tests compared with uncompressed video. We describe selected successful real-world deployment use cases based on our open-source implementation within the UltraGrid framework, such as trans-Atlantic 4K interactive video streaming during the CineGrid 2011 workshop. As discussed in the paper, the proposed approaches to parallelization provide sufficient performance even for the future generation of 8K video processing systems, currently limited by availability of camera and display hardware.     

Low bit-rate information hiding method based on search-order-coding technique

Information hiding method with low bit rate is important in secure communications. To reduce bit rate we propose a new embedding method in this paper based on SOC (search-order coding) compression technique. Compared to Chang et al.’s scheme in 2004, our scheme completely avoids the transform from SOC coding to OIV (original index values) coding to significantly reduce bit rate. In order to further reduce bit rate, Chang et al. proposed a reversible data hiding scheme using hybrid encoding strategies by introducing the side-match vector quantization (SMVQ) in 2013. But it needed additional 1 bit indicator to distinguish the two statuses to determine OIV is belonged to G1 or G2. This overhead gave a large burden to compression rate and could not reduce the bit rate significantly. In contrast, our scheme completely avoids this indicator. The experimental results show that the proposed method can efficiently reduce the bit rate and have the same embedding capacity compared with Chang et al.’s scheme in 2004 and Chang et al.’s scheme in 2013. Moreover, our proposed scheme can also achieve a better performance in both the embedding capacity and bit rate than other related VQ-based information hiding schemes.