共查询到19条相似文献,搜索用时 63 毫秒
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运动估计占据TMPEG-4形状编码90%以上的运算量,本文依据MPEG-4中形状信息的自身特性,提出了自适应二值运动估计算法。算法首先扫描参考帧,得出其有效搜索区域——边界掩模。在匹配运算时使用1bit的异或运算代替原有的加法运算。在搜索中根据二值Alpha块的运动特性自适应的采用不同的搜索模板进行搜索,对于静止点直接中止搜索。兼顾了搜索速度和精度。实验结果表明,在码字长度相仿的情况下,本算法的平均搜索点数仅相当于MPEG-4原有搜索算法的5%,有效提高了形状编码速度。 相似文献
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《中国计量学院学报》2017,(1):103-107
在视频编码中,DCT系数分布模型是率失真理论模型的基础,视频量化一般可分别为硬判决量化(HDQ)以及软判决量化(SDQ),SDQ算法能实现最优编码性能,但其中维特比算法会导致严重的系数间串行处理依赖.比较而言,基于死区(deadzone)的HDQ算法率失真性能略有损失,但是不考虑系数间的相关性.提出了一种基于分段逼近TCM模型(Transparent Composite Model)的自适应硬判决量化算法,采用更精确的DCT分布估计模型,估算不同频率分量DCT系数的分布参数.根据模型参数及DCT系数分布参数,优化构造自适应的死区偏移量模型.实验表明,相对于固定偏移量HDQ算法,其编码性能非常接近于SDQ算法. 相似文献
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《中国计量学院学报》2017,(2):241-246
在视频编码器中,软判决量化可获得最优编码性能,但其中维特比算法会导致严重的系数间串行处理依赖.比较而言,基于死区的硬判决量化算法率失真性能有所损失,但不存在系数间依赖,且非常适合硬件并行流水处理.今采用离线统计的方法,分析余弦变换系数的分布情况,量化余数对量化的具体影响,构建了基于余弦变换系数分布参数,量化余数的自适应偏移模型.基于该模型提出一种内容自适应的硬判决量化算法.仿真结果表明,该算法在保证并行化处理的条件下,其编码性能相比于传统的硬判决量化有一定的提升,可接近软判决量化算法性能. 相似文献
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《中国计量学院学报》2016,(1)
针对高效视频编码(HEVC)帧内编码算法计算复杂度高的问题,提出了一种基于纹理的HEVC编码块尺寸快速决策算法.首先,提出了编码块四个方向的纹理复杂度衡量指标,再通过训练视频序列选取在不同量化参数(QP)下的最佳阈值,最后根据阈值判断当前编码块的纹理复杂度,纹理复杂度高的编码块跳过率失真(RD)代价的计算,纹理复杂度低的编码块将会终止划分.实验结果表明,在全帧内模式配置下,与HM10.0相比较,该算法的编码时间可缩短45.3%,同时BD-Bitrate(Bjontegaard Delta Bitrate)增加了1.27%,BD-PSNR(Bjontegaard Delta Peak Signal-to-noise Rate)减少了0.058dB;与GEC-LEC算法相比,编码时间可节省3%,BD-Bitrate增加了0.5%,BD-PSNR减少了0.023dB. 相似文献
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基于快速运动估计算法UMHexagonS的研究 总被引:1,自引:0,他引:1
UMHexagonS算法已经被视频编码标准H.264正式采纳作为整像素的快速运动估计算法。该算法的运算量相对于快速全搜索算法可节约90%以上,同时能够保持较好的率失真性能。本文结合JM10.2的源代码对UMHexagonS算法进行了分析,并对该算法进行了改进。通过利用运动矢量间的相关性,采用一种新的自适应的非对称十字形模板来代替原算法中的非对称十字形模板,并将改进的算法在JM10.2测试模型上进行了验证。实验结果表明,本文建议的方法在保证编码性能的同时,可以有效减少运动估计所需要的时间。 相似文献
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主要学习研究H.264标准中的关键技术,H.264标准是最新的视频编码标准,它采用一系列先进的编码技术,在编码效率、抗误码能力、网络适应性等方面表现出超越以往各标准的优势,H.264的研究和应用将大大推进视频技术的发展. 相似文献
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《成像科学杂志》2013,61(6):339-350
AbstractThis paper presents a well organised fast mode decision scheme for H.264/AVC that systematically integrates and deploys applicable predictive resources using constructive compromise. This scheme is constructed by primary SKIP mode checking, spatial prior temporal hard decision (STHD), and succinct mode decision (SMD). The STHD is connected with the predictive macroblocks searched. In STHD, only when spatial hard decision fails, temporal hard decision is performed using the potential partition characteristic vector (PPCV) addressed. If it fails, too, then SMD takes care of mode checking also using PPCV. The SMD consists of succinct P16?×?16 mode decision and succinct geometric/statistical extension examination, which are formed as an effective two-stage judgment. Extensive experimental results demonstrate that the proposed method by systematically deploying the predictive resources can achieve 58–74% runtime savings in encoding QCIF, CIF and high definition videos with low performance losses. In addition, most processes of the proposed scheme could be implemented on logical operations, only. 相似文献
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《成像科学杂志》2013,61(3):311-319
AbstractIntra coding is used for reducing the spatial redundancy in video coding. H.264 supports several macroblocks of predictions for intra coding such as luma block four 16×16 modes, nine 4×4 modes and chroma block four modes, which significantly improve intra coding efficiency, but increase the encoding complexity. In order to select the best mode, we need to calculate the cost of the various modes. In this paper, a fast intra prediction mode decision for H.264/AVC video coding is proposed. Based on Laplacian, this intra prediction mode decision detects edges and selects the best mode for the block. This mode decision can shorten the time to reduce the encoding time. The experimental results show that the proposed algorithm achieves an encoding time saving of 70% on average. 相似文献
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H.264 takes rate distortion optimisation (RDO) technique to perform intra and inter mode decision and achieves higher coding efficiency, but the objective distortion metric such as mean square error (MSE) is employed in traditional RDO framework, which cannot acquire optimal subjective quality. In this paper, structural similarity (SSIM)-based subjective distortion is applied to RDO-based intra mode decision in H.264 I frame video coding, and a linear SSIM distortion model is firstly proposed and SSIM-based rate distortion cost function for intra mode decision is defined. Furthermore, a content adaptive frame layer Lagrange multiplier adjustment scheme is proposed to balance the tradeoff between rate and SSIM distortion better. Experimental results show that, the proposed method encodes image structural information more effectively and thus acquires better perceptual quality and subjective RDO performance compared with objective distortion-based RDO method. Under the same perceptual quality, our scheme achieves about 8·03% I frame bit rate reduction on average for various sequences over MSE-based RDO employed in JM reference software. 相似文献
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针对最新的视频编码标准H.264,设计了一种基于差错估计的容错算法。该算法结合信道条件,估计差错在视频编码帧之间的扩散;根据每个宏块差错的程度,自适应地判断是否对该宏块进行帧内编码,从而抑制差错的积累。在存在反向信道的环境中,该算法可以利用解码器反馈的实际宏块错误信息,跟踪差错扩散,对其进行更准确的估计,以提高容错性能。仿真表明,在各种信道条件下,该算法相对于随机帧内宏块更新算法.重建图像平均峰值信噪比有1.3~2.5dB的提高。同时,该算法对信道估计的要求不高,运算量和存储量的增加较低,具有实用性。 相似文献
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针对大规模图集的子图查询问题,给出了一种基于节点与决策模式映射(NDFM)的索引结构——NDFM-Index,并在此索引结构的基础上提出了一种图集的子图查询算法。NDFM-Index利用图中关键节点所携带的结构信息以及邻居的标号分布,与决策模式形成映射,从而不通过枚举直接得到查询图所包含的索引模式,得到更小的候选集。理论与实验的分析结果表明,该算法不但能避免索引筛选过程中对查询图子图的枚举过程,而且能显著地减小候选集尺寸,进而大大降低查询图与候选集之间的子图同构测试次数,提高查询效率。 相似文献
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A particular decision-making process that is needed by most firms who produce joint products is the one requiring an assessment of desirability of further processing joint products beyond the split-off point. The purpose of this paper is to develop an algorithm for optimizing a joint products further processing decision under the theory of constraints. To fit the jointly produced characteristic of joint products and the sequential produced characteristic between each joint product and its further processing product, the algorithm is composed of seven steps. These steps consider every bottleneck resource to the decision-making process by computing a priority ratio to establish its priority sequence. According to the priority sequence of the most constrained resource, the initial master production schedule is developed. Then, the following steps find the best path to reach the optimal solution under the guidance of all bottleneck resources. Due to its accessibility and comprehensibility, the TOC-based algorithm developed by this paper is a practical tool for obtaining the optimal joint products further processing decision. 相似文献
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基于EEMD的振动信号自适应降噪方法 总被引:2,自引:4,他引:2
摘 要:应用集合经验模式分解(Ensemble empirical mode decomposition ,EEMD)能有效抑制模态混叠的特性,根据白噪声经经验模式分解(Empirical mode decomposition, EMD)后其固有模式函数(intrinsic mode functions ,IMF)分量的能量密度与其平均周期的乘积为一常量这一特点设计了自动选择IMF分量重构信号的算法,提出了基于EEMD的振动信号自适应降噪方法。对仿真信号和滚动轴承振动信号的降噪结果表明了该降噪方法的可行性和有效性。 相似文献