一种新的视频编码的块运动估计算法

本文提出了一种连续判别的非线性预测搜索ＮＰＳＳＤ块运动估计算法,可以用于视频压缩的一些国际标准,如Ｈ．２６１,Ｈ．２６３,ＭＰＥＧ１,ＭＰＥＧ２,ＨＤＴＶ中。ＮＰＳＳＤ算法充分利用了序列图像的实际运动矢量与预测矢量之间的位移的空间分布特性－－中心偏置分布特性和时间上的相关特性,并在搜索过程中采用了中止判别和搜索判别,可以明显地减少运动搜索复杂度。仿真表明这种算法减少了搜索次数,提高了搜索效率,降低     

Homography-based block motion estimation for video coding of PTZ cameras

Due to the constrained movement of pan-tilt-zoom (PTZ) cameras, two frames in the video sequences captured by such cameras can be geometrically related by a relationship (homography). This geometric relationship is helpful for reducing the spatial redundancy in video coding. In this paper, by exploiting the homography between two frames with optical flow tracking algorithm, we propose a novel homography-based search (HBS) algorithm for block motion estimation in coding the sequences captured by PTZ cameras. In addition, adaptive thresholds are adopted in our method to classify different kinds of blocks. Compared with other traditional fast algorithms, the proposed HBS algorithm is proved to be more efficient for the sequences captured by PTZ cameras. And compared to our previous work in ICME (Cui et al., 2011), which only deals with pan-tilt (PT) camera and calculates the homography with mechanical devices, in this extended work we compute the homography by using information on images instead.     

Novel two-layer motion estimation for video coding

In this paper,we proposed a novel Two-layer Motion Estimation （TME） which searches motion vectors on two layers with partial distortion measures in order to reduce the overwhelming computational complexity of Motion Estimation （ME） in video coding.A layer is an image which is derived from the reference frame such that the sum of a block of pixels in the reference frame determines the point of a layer.It has been noticed on different video sequences that many motion vectors on the layers are the same as those searched on the reference frame.The proposed TME performs a coarse search on the first layer to identify the small region in which the best candidate block is likely to be positioned and then perform local refined search on the next layer to pick the best candidate block in the located small area.The key feature of TME is its flexibility of mixing with any fast search algorithm.Experimental results on a wide variety of video sequences show that the proposed algorithm has achieved both fast speed and good motion prediction quality when compared to well known as well as the state-of-the-art fast block matching algorithms.     

Edge detection-based block motion estimation

Block matching algorithms that predict the motion field using blocks of pixels use search heuristics to find the best match. Blocks on the boundary of moving objects create problems for accurately predicting the motion vectors, and make for uncomfortable viewing. The authors propose a new method for accurately determining the motion vectors using the edge-matching criteria. This method gives good motion estimation, with reduced computational requirements     

Three-dimensional motion estimation of objects for video coding

Three-dimensional (3-D) motion estimation is applied to the problem of motion compensation for video coding. We suppose that the video sequence consists of the perspective projections of a collection of rigid bodies which undergo a rototranslational motion. Motion compensation can be performed on the sequence once the shape of the objects and the motion parameters are determined. We show that the motion equations of a rigid body can be formulated as a nonlinear dynamic system whose state is represented by the motion parameters and by the scaled depths of the object feature points. An extended Kalman filter is used to estimate both the motion and the object shape parameters simultaneously. The inclusion of the shape parameters in the estimation procedure adds a set of constraints to the filter equations that appear to be essential for reliable motion estimation. Our experiments show that the proposed approach gives two advantages. First, the filter can give more reliable estimates in the presence of measurement noise in comparison with other motion estimators that separately compute motion and structure. Second, the filter can efficiently track abrupt motion changes. Moreover, the structure imposed by the model implies that the reconstructed motion is very natural as opposed to more common block-based schemes. Also, the parameterization of the model allows for a very efficient coding of the motion information     

视频编码中的块运动估计算法

在视频压缩的一些国际标准，如Ｈ．２６１，Ｈ．２６３，ＭＰＥＧ０－１，ＭＰＥＧ－２，ＨＤＴＶ中，视频系统编码器的复杂性最主要取决于运动估计。下文以ＭＰＥＧ－２编码器为例，通过计算机模拟实验，得出了一些常用运动估计算法的对比实验结果，以及采用常用的几种匹配函数的对比实验结果。     

针对多视角视频编码的快速运动估计方法

为了提高多视角视频编码系统中运动估计速度,提出了一种基于马尔科夫链模型的快速运动矢量估计算法。该算法充分利用帧间、视角间相关性,建立预测矢量状态集合。通过马尔科夫链模型的状态转移概率,对预测矢量进行提前测试。然后利用提前退出准则,实现快速运动矢量估计。实验结果表明,与单独采用全搜索算法比较,该算法对于多视角视频序列运动估计速度可以提高99%以上,PSNR平均降低0.16dB。提出的算法对多视角视频编码系统的运动估计效率提升明显。     

一种适用于AVS-M的自适应快速运动估计算法

为了减小移动视频编码标准(AVS-M)中运动估计模块的复杂度,提出了一种快速、有效的块匹配运动估计算法.该算法充分利用了视频图像中运动矢量场的中心偏置特性和时空相关性,根据运动类型自适应的选择搜索起点和搜索策略,结合改进的搜索模板和高效搜索中止准则,有效地降低了运动估计的运算量.实验结果表明,该算法在保证搜索精度的同时,大大减少了搜索点数.     

Fast multiresolution motion estimation algorithms for wavelet-based scalable video coding

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.     

A low-power analog motion estimation processor for digital video coding

Analog circuit techniques can be beneficially applied to reduce the circuit complexity and power consumption of motion estimation processors for digital video encoding. However, analog circuits are sensitive to mismatch which affects motion estimation. This paper presents the design of an analog motion estimation processor which overcomes these limitations. A novel architecture is described featuring pixel reuse and input offset error cancellation. The proof-of-concept realization was fabricated in 0.8-/spl mu/m CMOS, and operates on 4/spl times/4 pixel blocks and a search area of 8/spl times/8 pixels. However, the architecture is scalable to larger block sizes and more advanced technologies. Measured results for various QCIF video sequences at 15-f/s showed excellent PSNR performance. The prototype dissipates 0.9 mW of power from a single 3-V power supply and occupies an area of 0.95 mm/sup 2/. Energy consumption is 1.51 nJ per motion vector.     

A VLSI architecture for variable block size video motion estimation

With the advent of new video standards such as MPEG-4 part-10 and H.264/H.26L, demands for advanced video coding, particularly in the area of variable block size video motion estimation (VBSME), are increasing. In this paper, we propose a new one-dimensional (1-D) very large-scale integration architecture for full-search VBSME (FSVBSME). The VBS sum of absolute differences (SAD) computation is performed by re-using the results of smaller sub-block computations. These are distributed and combined by incorporating a shuffling mechanism within each processing element. Whereas a conventional 1-D architecture can process only one motion vector (MV), this new architecture can process up to 41 MV sub-blocks (within a macroblock) in the same number of clock cycles.     

两种实时、低码率视频编码的运动估计搜索算法

先提出实时、低码率视频编码对运动估计搜索算法在运算时间和准确度上的要求，总结归纳了钻石搜索法和两步法的具体算法，通过与几种经典算法作比较，说明这两种算法更优，更适合用于实时，低码率视频编码，最后，以H．263的实现为例，说明了钻石搜索算法的具体实现。     

Robust global motion estimation oriented to video object segmentation.

Most global motion estimation (GME) methods are oriented to video coding while video object segmentation methods either assume no global motion (GM) or directly adopt a coding-oriented method to compensate for GM. This paper proposes a hierarchical differential GME method oriented to video object segmentation. A scheme which combines three-step search and motion parameters prediction is proposed for initial estimation to increase efficiency. A robust estimator that uses object information to reject outliers introduced by local motion is also proposed. For the first frame, when the object information is unavailable, a robust estimator is proposed which rejects outliers by examining their distribution in local neighborhoods of the error between the current and the motion-compensated previous frame. Subjective and objective results show that the proposed method is more robust, more oriented to video object segmentation, and faster than the referenced methods.     

Fast motion and disparity estimation for HEVC based 3D video coding

The emerging international standard for high efficiency video coding (HEVC) based 3D video coding (3D-HEVC) is an extension of HEVC. In the test model of 3D-HEVC, variable size motion estimation (ME) and disparity estimation (DE) are both employed to select the best coding mode for each treeblock in the encoding process. This technique achieves the highest possible coding efficiency, but it brings extremely high computational complexity which limits 3D-HEVC from practical applications. In this paper, a fast ME/DE algorithm based on inter-view and spatial correlations is proposed to reduce 3D-HEVC computational complexity. Since the multi-view videos represent the same scene with similar characteristic, there is a high correlation among the coding information from inter-view prediction. Besides, the homogeneous regions in texture video have a strong spatial correlation, and thus spatially neighboring treeblocks have similar coding information. Therefore, we can determine ME search range and skip some specific ME and DE rarely used in the previously coded view frames and spatially neighboring coding unit. Experimental results demonstrate that the proposed algorithm can significantly reduce computational complexity of 3D-HEVC encoding while maintaining almost the same rate-distortion performance.     

A new distortion measure for motion estimation in motion-compensated hybrid video coding

In the video coding standards MPEG-x and H.26x, a motion-compensated prediction technique is used for enhancing the coding performance of bitrate reduction or peak signal to noise ratio (PSNR) improvement. This technique takes advantage of the correlation between consecutive frames in the time domain, which is relatively higher than that between adjacent blocks in the spatial domain. In order to utilize the correlation between consecutive frames, the conventional video coding standards have used the motion estimation (ME) and compensation technique, where the Sum of the Absolute Differences (SAD) is usually used as the distortion measure. The ME estimates the reference block that could minimize the residual signal between the current and reference blocks. However, the SAD is not appropriate to the specific sequences that have global or local illumination changes. In addition, the high-resolution video sequences have higher spatial correlation than the low-resolution video sequences in general. Therefore, a new distortion measure that can consider spatial and temporal correlation simultaneously may be helpful to enhance the coding performance. The proposed distortion measure searches for a reference block that minimizes the motion-compensated residual signal when the DC-component is predicted. In our proposed algorithm, the maximum BD-rate improvement is up to 13.6% for illumination-changed video sequences, and the average BD-rate improvement is 6.6% for various high-resolution video sequences in the baseline profile.     

Block-based motion field segmentation for video coding

In the past few years, motion compensation has been widely used in the coding of image sequences. Most of motion estimation and compensation schemes belong to block-based framework. The framework simplifies the complexity of motion estimation, but gives over constraints to the motion field, which results in worse accuracy on the boundary of moving objects. This paper presents a novel technique for raising motion field accuracy. It uses several pre-defined pattern types to segment the motion fields of the previous frame of a sequence. The segmentation is based on the MAP framework that uses iterative method to obtain the solution. In addition, we develop a predictive scheme to predict the location of motion field discontinuities in the current frame, which further reduces the side information for the representation of segmentation.     

Closed-loop motion compensation for video coding standards

In the classical block-matching motion-estimation approach, the motion vectors which result in minimum distortion between the estimated and the actual image block are chosen. However, these motion vectors may not be optimal in terms of coding efficiency. An analysis by synthesis method which selects the optimal motion vectors, using the resulting bit rate and distortion, is presented. A significant reduction in bit rate is achieved with virtually no degradation in objective image quality. H.263 is used in simulation experiments to test the algorithm     

Adaptive block tree structure for video coding

The Joint Video Exploration Team (JVET) has studied future video coding (FVC) technologies with a potential compression capacity that significantly exceeds that of the high-efficiency video coding (HEVC) standard. The joint exploration test model (JEM), a common platform for the exploration of FVC technologies in the JVET, employs quadtree plus binary tree block partitioning, which enhances the flexibility of coding unit partitioning. Despite significant improvement in coding efficiency for chrominance achieved by separating luminance and chrominance tree structures in I slices, this approach has intrinsic drawbacks that result in the redundancy of block partitioning data. In this paper, an adaptive tree structure correlating luminance and chrominance of single and dual trees is presented. Our proposed method resulted in an average reduction of −0.24% in the Y Bjontegaard Delta rate relative to the intracoding of JEM 6.0 common test conditions.     

一种基于子搜索格雷码核的快速视频块运动估计算法

快速视频块运动估计是视频编码中的一个重要问题。在格雷码核( GCK)算法的基础上,提出一种改进的子搜索格雷码核( Sub-GCK)算法。理论上的计算复杂度分析表明：提出的子搜索格雷码核算法的运算量大约为原始格雷码核算法的22.1%。实验比较了子搜索格雷码核算法、原始格雷码核算法和其他几种常见的运动估计算法的编码性能,结果显示：新算法在保证编码质量的前提下,有效降低了运动估计时间,时间约为原始格雷码核算法的41.9%。