H.264帧内预测与帧间块模式选择快速算法

针对H.264帧间预测时的多子块模式选择和帧内预测的多模式选择问题,提出了一种实用的基于统计门限的模式快速选择算法,通过门限设定有效限定了编码模式的选择范围.多组视频序列的实验结果表明,基于统计门限的帧内预测模式选择算法在Ⅰ帧的PSNR值有微小变化的情况下,大大降低了编码时间,Ⅰ帧的编码时间降低17%～23%,PSNR下降不到0.4%.基于统计门限的帧间块模式选择算法使得平均PSNR值下降了0.047dB(PSNR最大下降不到1%),但是相对全模式预测时,编码器速度提高了20%～30%.     

一种基于预测模式的H.264/AVC视频信息隐藏改进算法

提出了一种基于帧内预测模式调制的H.264/AVC视频信息改进隐藏算法.选择参考像素亮度值接近的帧内4×4块,通过对预测模式值进行调制以实现隐秘信息的嵌入,而预测模式调制过程是将最优预测模式变为满足嵌入条件的具有率失真开销最小的预测模式,以尽量减小预测模式的改变对视频客观质量的影响.信息的提取过程不需要原始载体视频,也...     

一种新的面向隔行视频的AVS帧内预测模式

详细介绍了AVS1-P2中的帧内预测和MBAFF技术,提出了一种新的帧内预测模式.通过分析其中的5种亮度帧内预测模式和新帧内预测模式的相关性利用度,证明该模式很好地利用了隔行视频像素的空间分布特点,与原有的预测模式相比,更好地去除了图像块之间的空间相关性.实验表明该模式可以在标清、高清隔行视频的帧内预测上获得平均0.12dB以上的信噪比增益,平均减少1.77%的码流,是一种有效提高编码效率的预测模式.     

H.264帧间预测模式选择算法研究与优化

H.264出色的压缩性能是以计算复杂度的提高为代价的。使用快速帧间预测模式选择算法是提高H.264编码速率的一种有效方法。文中对H.264帧间预测模式选择的复杂度进行分析之后，对基于X264参考程序的帧间预测算法提出改进，测试结果显示这种改进能将H．264的编码速率提高55％左右。     

基于编码模式的H.264/AVC视频信息隐藏算法

本文提出一种基于编码模式的H.264/AVC信息隐藏方法,通过调制某些宏块的编码模式,分别在Ⅰ帧、P帧和B帧中嵌入隐秘信息.对帧内4x4预测模式的宏块,是通过调整宏块中某个4×4块的编码模式嵌入隐秘信息;对P帧和B帧其它类型的宏块,则是通过调整宏块的编码模式嵌入隐秘信息,模式调整后对宏块做了优化处理.在模式调制过程中引入率失真代价,取得了较好的率失真平衡,减小了隐秘信息嵌入后对视频质量和视频码流的影响.该算法可以实现隐秘信息的快速提取,满足视频实时处理的要求,实验仿真结果证明了该算法的有效性.     

H.264编码模式选择的研究

研究H.264的编码模式选择方案,根据视频序列的时域相关性和空域相关性的关系,模式选择包括帧内预测和帧间预测,帧间预测基于率失真函数,在一帧图像的编码中则可以采用提前终止预测方向的方法降低编码器端的复杂度.     

一种基于边缘幅值分布的相关跟踪算法

针对空中目标的跟踪环境提出一种边缘幅值分布的相关跟踪算法,利用目标的边缘幅值分布作为目标的特征模板,通过求取当前帧中目标特征与目标特征模板相关系数的最优解来进行目标跟踪.与采用对称核函数的均值迁移目标跟踪算法相比,采用目标边缘点作为核函数中的样本点,参与计算的样本点为核窗口中样本的5%～10%,使图像处理速度达到了50帧/s以上,满足了实时跟踪的要求.在跟踪过程中,以目标相邻帧间特征向量的Bhattacharyya相关系数作为目标特征模板的更新判据,实验中相邻帧间目标特征向量的Bhattacharyya系数保持在0.95～1.0,满足模板实时更新的要求,为稳定跟踪提供了保障.     

一种基于HVS特性的视频质量评测方法

本文针对视频质量的评测应用,对传统峰值信噪比(PSNR)算法加以改进.通过在视频帧内图像和帧间图像的处理过程中引入人眼视觉系统(HVS)的主要特性,克服传统PSNR算法在序列质量检测应用方面的缺陷.方法在帧内图像处理上利用人眼对边缘轮廓失真具有较强敏感性的特点,设计了基于图像边缘的检测方案以提高对典型空域失真的检测性能;在帧间图像处理上,通过测量帧间时域能量的变化,获得序列在时域轴上的典型特征,并据此对空域检测结果进行修正.通过上述改进,算法能在保持传统PSNR算法简易性的同时,提升其检测结果与主观感受的相关性;同时算法的计算量并不复杂,易于在检测设备中实现系统集成     

帧内预测模式快速选择方法研究

H．264标准中的帧内预测方法在很大程度上提高了帧内编码的效率,但同时也增加了编码复杂度。对其中运算量很大的预测模式选择策略和几种改进方法进行了分析,提出了一种自适应的快速预测模式选择方法。该方法主要基于最可能预测模式的自适应阈值和预测模式的选择计算。实验表明,该方法在基本保持了帧内压缩效率的同时,提高了编码的时间效率,而且能够较好支持SIMD指令,有利于汇编指令优化。     

AVS视频编码标准的帧间预测算法研究

介绍AVS视频编码标准的帧间预测技术特点,对帧间预测算法进行分析和研究,为视频帧间编码提供理论依据。     

Probabilistic property prediction

Uncertainty must be characterized accurately for engineering applications because it arises from a number of sources each of which are exacerbated as the complexity increases. Having limited data also intensifies concerns about the uncertainty. Historically the design of structural components for high reliability applications has required an extensive test program to validate the design and service of the component. With the development of new materials and alloys and with an increased concern for safety, validation of a design is even more difficult. In order to meet regulatory demands for components for extended service and yet reduce the costs of preproduction, an approach which incorporates extensive scientific modeling with a limited experimental effort is desired. To that end, this effort proposes a methodology, which integrates limited data with science based modeling, so that the uncertainty is represented adequately. The approach combines classical Bayesian methods and model synthesis with data. The approach is illustrated using the yield strength of a typical turbine disk alloy. Fusion of science based modeling with data greatly improves estimation and prediction, which reduces the uncertainty. Even crude models are more beneficial than statistical data analysis alone. The approach allows for a significant reduction in data in contrast to purely statistical approaches.     

Cyclone track prediction

This is a review paper based on tropical cyclone research that was mostly carried out at the Florida State University. In this review we address a number of modelling issues such as: Explicit specification of the constant flux layer, cloud-radiative interaction and low cloud, cumulus parameterization, physical initialization, the ensemble of hurricane track forecasts and cloud forecasts. Among these the areas that have demonstrated the most sensitivity on tropical cyclone tracks, landfall and intensity are: resolution, cumulus convection, sea surface temperatures, soil moisture and orography around the ocean basin. This work was supported by NSF Grant No. ATM-9710336, ONR Grant No. N00014-95-1-1132, NASA TRMM Grant No. NAG5-4729 and the NOAA Grant No. NA67WA0406.     

Crash injury prediction model

Automobile crash injury was analyzed using data from the Crash Performance Injury Report (CPIR) for crashes which occurred since 1 January 1970 involving 1969 or newer cars, vans and pickup trucks. An injury prediction model was developed using delta V, vehicle weight, occupant age, seating position, crash configuration, and restraint usage to predict expected AIS. Expected AIS was then used to estimate the probability of death and severe injury. The model estimates were found to approximate the observed probability of death and severe injury from the National Crash Severity Study (NCSS) data file.     

经典彩色预测模型

针对印刷中原稿和复制品之间存在的色差这一事实,详细介绍了至今为止的几种经典彩色预测模型:如直接针对半色调印刷过程的Neugebauer方程,Yule-Nielsen模型和基于减色原理的Kubelka-Munk理论.通过调节模型中的变量来达到控制色差的目的.     

Sealing performance prediction software

Elastomer seals are widely used throughout industry and seal failure can be very expensive, in both financial and safety terms. One failure mode causing major concern is progressive degradation. It is generally of a long term nature and its extent and consequences in service can be particularly difficult to predict. BHR Group has developed seal-life prediction software in a user friendly, Windows format to address the problem of progressive seal degradation.