共查询到18条相似文献,搜索用时 187 毫秒
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文章提出一种直接对压缩视频码流进行全局运动估计的新算法。为了提高估计精度和计算效率.提出一种新的视频背景前景分割方法,该算法利用运动矢量和AC系数实现背景与前景分割。基于分割的结果,采用背景宏块的运动矢量进行全局运动参数估计。实验验证了提出的全局运动估计算法的计算效率和精度。 相似文献
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基于特征点匹配技术的运动估计及补偿方法 总被引:26,自引:7,他引:19
提出一种用于电子稳像技术的全局运动估计和补偿算法。通过特征点匹配,求其局部运动矢量;将其代入变换模型所得的线性力程组,求其全局运动矢量。用均值滤波的方法确定各帧的补偿量,并代入给定的变换模型对当前图像进行变换,实现对视频图像序列的稳定处理。为了减小特征点匹配计算的复杂性,加快匹配速度,还采用了多分辨率图像金字塔匹配策略。实验表明.使用该算法对于提高动态图像的稳定性有较好的效果。 相似文献
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为了快速准确估计出视频序列中存在的全局平移抖动,分析影响全局运动估计精度的各种常见因素,归纳其特点,同时结合相关基础理论,以C-1BT变换为基础,提出一种基于预选算法的快速全局平移运动估计算法。首先,在估计局部运动矢量前,采用预选算法保留能很好代表全局运动性质的部分宏块。其次,根据预选块的特点改变传统自适应十字搜索法(Adaptive Rood Pattern Search,ARPS)的臂长预测部分,减少搜索陷入局部最优的风险。最后,采用平移运动模型得到最终参数。实验仿真结果证明提出方法的快速性和鲁棒性。 相似文献
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基于运动矢量多级分析的视频全局运动估计 总被引:3,自引:0,他引:3
基于运动矢量场的视频全局运动估计相较于基于像素的估计方法具有较低的计算复杂度,因而广泛应用于视频分割及视频压缩等领域中。然而噪声和前景目标等外点区域的存在,降低了全局运动估计的准确性。为了提高全局运动估计的准确度,该文提出一种基于运动矢量多级分析的全局运动估计算法,该算法根据局部运动与全局运动的运动特性差异自适应地滤除前景目标区域,由邻域矢量间相似性度量检测出纹理平滑周期区域,最后滤除孤立的噪声区域,由滤波得到的内点区域求解全局运动参数。实验结果表明,该方法能有效地滤除外点区域,提高全局运动估计的准确性。 相似文献
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一种改进的相机全局运动估计方法 总被引:1,自引:0,他引:1
提出了一种改进的相机全局运动估计方法。首先给出了相机的全局运动模型,然后对传统的模板匹配方法的模板更新和匹配准则等环节进行了改进。仿真结果表明,该方法能以较小的资源消耗有效地解决相机的全局运动估计问题。 相似文献
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本文提出了RTSG图像预分析和多直线全局运动估计方法,该方法首先根据光流场方程得到RTSG图像,并对RTSG图像进行预分析以去除图像中的外点和确定全局运动模型,然后提取多个直线特征元,利用直线特征元估计局部运动参数,最后用局部运动参数和与之相关的权值进行全局运动估计。 相似文献
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In this paper, we propose an efficient, robust, and fast method for the estimation of global motion from image sequences. The method is generic in that it can accommodate various global motion models, from a simple translation to an eight-parameter perspective model. The algorithm is hierarchical and consists of three stages. In the first stage, a low-pass image pyramid is built. Then, an initial translation is estimated with full-pixel precision at the top of the pyramid using a modified n-step search matching. In the third stage, a gradient descent is executed at each level of the pyramid starting from the initial translation at the coarsest level. Due to the coarse initial estimation and the hierarchical implementation, the method is very fast. To increase robustness to outliers, we replace the usual formulation based on a quadratic error criterion with a truncated quadratic function. We have applied the algorithm to various test sequences within an MPEG-4 coding system. From the experimental results we conclude that global motion estimation provides significant performance gains for video material with camera zoom and/or pan. The gains result from a reduced prediction error and a more compact representation of motion. We also conclude that the robust error criterion can introduce additional performance gains without increasing computational complexity. 相似文献
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提出一种粗到精分块金字塔连续排除算法用于减少块匹配运动估计所需计算量.金字塔可以方便地从当前搜索窗的积分帧构建,连续的排除从金字塔顶层到底层逐级进行,将最小SAD值与金字塔提供的一系列越来越紧的界值相比较,可以跳过不必要的SAD计算.这样,算法在保证获得与全搜索算法相同精度的前提下,计算复杂度大大降低.仿真实验结果验证了本文算法与全搜索算法和几种快速搜索算法相结合的有效性. 相似文献
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This paper proposes a two-stage global motion estimation method and a hybrid coding algorithm for the model-based coding. In the first stage, global motion is estimated by the feature-based algorithm. The estimated result is further refined by the gradient method. The two-stage estimation algorithm is performed hierarchically to remove the influence of the local facial expression. In the estimation process, we also utilize the steerable pyramid to improve accuracy. The facial expression region is coded by the clip-and-paste method, and is predicted by a classified prototype coding technique. The prototype coding technique can greatly improve the coding efficiency for the facial expression. The areas, which are difficult to be described by generic models, are encoded by the proposed hierarchical motion segmentation algorithm. We segment the image to different moving areas which can be modeled by affine models in a split-and-merge manner. The segmented results with the estimated affine models can give good prediction for the unmodeled regions. Computer simulation results show that the proposed complete model-based coding scheme gives very good performance in terms of peak signal-to-noise ratio and compression ratio 相似文献
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网格模型的运动估计和跟踪在基于模型的编码方法中占有重要的地位,在现有的网格运动估计技术中,六边形匹配(Hexagonal Matching)是一种有效的网格模型运动估计算法,它采用局部最优和迭代策略相结合的方法得到较好的全局运动估计结果.六边形匹配算法由块搜索和迭代六边形匹配两步组成,同所有的基于模型的运动估计技术一样,六边形匹配算法也存在运算量大的问题难于满足实时编码需要.本文对六边形匹配算法从三个方面进行改进:用四步搜索替代全搜索、快速的纹理映射技术和有效的节点排序减少迭代次数.改进后的算法在基本上保证原算法的运动估计效率的情况下,算法的复杂度有明显的降低,使得基于模型的编码技术向实用化前进了一步. 相似文献
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《Signal Processing: Image Communication》2007,22(5):448-465
Motion estimation and compensation in wavelet domain have received much attention recently. To overcome the inefficiency of motion estimation in critically sampled wavelet domain, the low-band-shift (LBS) method and the complete-to-overcomplete discrete wavelet transform (CODWT) method are proposed for motion estimation in shift-invariant wavelet domain. However, a major disadvantage of these methods is the computational complexity. Although the CODWT method has reduced the computational complexity by skipping the inverse wavelet transform and making the direct link between the critically sampled subbands and the shift-invariant subbands, the full search algorithm (FSA) increases it. In this paper, we proposed two fast multiresolution motion estimation algorithms in shift-invariant wavelet domain: one is the wavelet matching error characteristic based partial distortion search (WMEC-PDS) algorithm, which improves computational efficiency of conventional partial distortion search algorithms while keeping the same estimate accuracy as the FSA; another is the anisotropic double cross search (ADCS) algorithm using multiresolution-spatio-temporal context, which provides a significantly computational load reduction while only introducing negligible distortion compared with the FSA. Due to the multiresolution nature, both the proposed approaches can be applied to wavelet-based scalable video coding. Experimental results show the superiority of the proposed fast motion estimation algorithms against other fast algorithms in terms of speed-up and quality. 相似文献
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视频帧纹理区域含有的大量周期重复模式常导致双向运动估计发生视频块的错匹配,从而导致帧率提升算法重建的内插视频质量衰退.为了克服该问题,提出提取视频帧的多个特征加入到块匹配中,以降低错匹配发生的可能性.由于视频天然具有彩色信息,因此色差分量首先被加入到块匹配中.另外,人眼时图像边缘较敏感,因此,由简单的Sobel算子计算出的梯度被使用去反应边缘特征并融入至块匹配.多特征匹配尽管可有效地提高运动估计精度,但也引入了较高的计算复杂度.为了减少计算复杂度,一个特殊模板被设计去将多特征合并到单平面上,那么,只需进行一次块匹配运算就可完成多特征的匹配,在节省计算复杂度的同时也提高了运动估计精度.仿真实验表明,该算法以较低的计算复杂度获得了良好的内插帧主客观质量. 相似文献