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motion estimation of elastic articulated objects from image contours

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Journal of Harbin Institute of Technology(New Series) 2008年第3期15卷 326-330页

作者：潘海朗戴跃伟石磊 College of Automation Nanjing University of Science & Technology Shanghai Berkeley Biology and Technology Limited Company

A new method of elastic articulated objects (human bodies) modeling was presented based on a new conic curve. The model includes 3D object deformable curves which can represent the deformation of human occluding contours. The deformation of human occluding contour can be represented by adjusting only four deformation parameters for each limb. Then, the 3D deformation parameters are determined by corresponding 2D contours from a sequence of stereo images. The algorithm presented in this paper includes deformable conic curve parameters determination and the plane, 3D conic curve lying on, parameter determination.

关键词： elastic articulated object, human body modeling motion estimation

6-DOF motion estimation using optical flow based on dual cameras

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Journal of Central South University 2017年第2期24卷 459-466页

作者：刘梦瑶王岩郭雷 School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China Science and Technology on Aircraft Control Laboratory Beihang University Beijing 100191 China

Because of its characteristics of simple algorithm and hardware, optical flow-based motion estimation has become a hot research field, especially in GPS-denied environment. Optical flow could be used to obtain the aircraft motion information, but the six-(degree of freedom)(6-DOF) motion still couldn't be accurately estimated by existing methods. The purpose of this work is to provide a motion estimation method based on optical flow from forward and down looking cameras, which doesn't rely on the assumption of level flight. First, the distribution and decoupling method of optical flow from forward camera are utilized to get attitude. Then, the resulted angular velocities are utilized to obtain the translational optical flow of the down camera, which can eliminate the influence of rotational motion on velocity estimation. Besides, the translational motion estimation equation is simplified by establishing the relation between the depths of feature points and the aircraft altitude. Finally, simulation results show that the method presented is accurate and robust.

关键词： optical flow motion estimation dual cameras six degree-of-freedom(6-DOF)

Fast motion estimation algorithm for H.264/AVC based on centered prediction

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Journal of Systems Engineering and Electronics 2010年第6期21卷 1103-1110页

作者： Wei Zhou Zhemin Duan Hongqi Hu School of Electronics and Information Northwestern Polytechnical University Xi'an 710072 P. R. China

H.264/AVC video coding standard can achieve roughly half of the bit-savings over MPEG2 and MPEG4 for a given quality. However, this comes at a cost in considerably increased complexity at the encoder and thus increases the difficulty in hardware implementation. The high redundancy that exists between the successive frames of a video sequence makes it possible to achieve a high data compression ratio. motion estimation （ME） plays an important role in motion compensated video coding. A fast motion estimation algorithm for H.264/AVC is proposed based on centered prediction, called centered prediction based fast mixed search algorithm （CPFMS）. It makes use of the spatial and temporal correlation in motion vector （MV） fields and feature of all-zero blocks to accelerate the searching process. With the initialized searching point prediction, adaptive search window changing and searching direction decision, CPFMS is provided to reduce computation in block-matching process. The experimental results show that the speed of CPFMS is nearly 12 times of FS with a negligible peak signal-noise ratio （PSNR） loss. Also, the efficiency of CPFMS outperforms some popular fast algorithms such as hybrid unsymmetrical cross multi-hexagongrid search and a novel multidirectional gradient descent search evidently.

关键词： H.264/AVC motion estimation motion vectors early termination.

A novel adjustable multiple cross-hexagonal search algorithm for fast block motion estimation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第8期8卷 1304-1310页

作者： XIE Chun-lai CHEUNG Chun-ho LIU Wei-zhong Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074 China Hong Kong Institute of Technology Hong Kong China

In this paper,we propose a novel adjustable multiple cross-hexagonal search(AMCHS) algorithm for fast block motion estimation. It employs adjustable multiple cross search patterns(AMCSP) in the first step and then uses half-way-skip and half-way-stop technique to determine whether to employ two hexagonal search patterns(HSPs) subsequently. The AMCSP can be used to find small motion vectors efficiently while the HSPs can be used to find large ones accurately to ensure prediction quality. Simulation results showed that our proposed AMCHS achieves faster search speed,and provides better distortion performance than other popular fast search algorithms,such as CDS and CDHS.

关键词： motion estimation Fast search algorithm Adjustable search patterns Threshold strategy Hexagonal search pattern

Super-Resolution Reconstruction of Image Sequence Using Multiple motion estimation Fusion

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Journal of Computer Science & Technology 2004年第3期19卷 405-412页

作者： ChengWang Run-ShengWang ATRNationalLaboratory NationalUniversityofDefenseTechnologyChangsha410073P.R.China

Super-resolution reconstruction algorithm produces a high-resolution imagefrom a low-resolution image sequence. The accuracy and the stability of the motion estimation (ME)are essential for the whole restoration. In this paper, a new super-resolution reconstructionalgorithm is developed using a robust ME method, which fuses multiple estimated motion vectorswithin the sequence. The new algorithm has two major improvements compared with the previousresearch. First, instead of only two frames, the whole sequence is used to obtain a more accurateand stable estimation of the motion vector of each frame; second, the reliability of the ME isquantitatively measured and introduced into the cost function of the reconstruction algorithm. Thealgorithm is applied to both synthetic and real sequences, and the results are presented in thepaper.

关键词： image sequence super resolution motion estimation fusion

Multi-Exposure motion estimation Based on Deep Convolutional Networks

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Journal of Computer Science & Technology 2018年第3期33卷 487-501页

作者： Zhi-Feng Xie Yu-Chen Guo Shu-Han Zhang Wen-Jun Zhang Li-Zhuang Ma Department of Film and Television Engineering Shanghai University Shanghai 200072 China Shanghai Engineering Research Center of motion Picture Special Effects Shanghai 200072 China Department of Software Science and Technology East China Normal University Shanghai 200062 China

In motion estimation, illumination change is always a troublesome obstacle, which often causes severely per- formance reduction of optical flow computation. The essential reason is that most of estimation methods fail to formalize a unified definition in color or gradient domain for diverse environmental changes. In this paper, we propose a new solution based on deep convolutional networks to solve the key issue. Our idea is to train deep convolutional networks to represent the complex motion features under illumination change, and further predict the final optical flow fields. To this end, we construct a training dataset of multi-exposure image pairs by performing a series of non-linear adjustments in the traditional datasets of *** estimation. Our multi-exposure flow networks （MEFNet） model consists of three main components： low-level feature network, fusion feature network, and motion estimation network. The former two components belong to the contracting part of our model in order to extract and represent the multi-exposure motion features; the third component is the expanding part of our model in order to learn and predict the high-quality optical flow. Compared with many state- of-the-art methods, our motion estimation method can eliminate the obstacle of illumination change and yield optical flow results with competitive accuracy and time efficiency. Moreover, the good performance of our model is also demonstrated in some multi-exposure video applications, like HDR （high dynamic range） composition and flicker removal.

关键词： motion estimation optical flow convolutional neural network multi-exposure

A pixel-based outlier-free motion estimation algorithm for scalable video quality enhancement

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Frontiers of Computer Science 2015年第5期9卷 729-740页

作者： Xuan DONG Jiangtao WEN Department of Computer Science and Technology Tsinghua University Beijing 100084 China

Scalable video quality enhancement refers to the process of enhancing low quality frames using high quality ones in scalable video bitstreams with time-varying qualities. A key problem in the enhancement is how to search for correspondence between high quality and low quality frames. Previous algorithms usually use block-based motion estimation to search for correspondences. Such an approach can hardly estimate scale and rotation transforms and always in- troduces outliers to the motion estimation results. In this paper, we propose a pixel-based outlier-free motion estimation algorithm to solve this problem. In our algorithm, the motion vector for each pixel is calculated with respect to estimate translation, scale, and rotation transforms. The motion relationships between neighboring pixels are considered via the Markov random field model to improve the motion estimation accuracy. Outliers are detected and avoided by taking both blocking effects and matching percentage in scale- invariant feature transform field into consideration. Experiments are conducted in two scenarios that exhibit spatial scalability and quality scalability, respectively. Experimental results demonstrate that, in comparison with previous algorithms, the proposed algorithm achieves better correspondence and avoids the simultaneous introduction of outliers, especially for videos with scale and rotation transforms.

关键词： motion estimation scalable video coding videosuper resolution.

Bioinspired Polarized Optical Flow Enables Turbid Underwater Target motion estimation

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Journal of Ocean University of China 2024年第4期23卷 915-923页

作者： CHENG Haoyuan ZHAO Shujie ZHU Jinchi YU Hao CHU Jinkui College of Engineering Ocean University of ChinaQingdao 266100China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of TechnologyDalian 116024China

Underwater target motion estimation is a challenge for ocean military and scientific *** this work,we propose a method based on the combination of polarization imaging and optical flow for turbid underwater target *** imaging can reduce the influence of backscattered light and obtain high-quality images *** optical flow shows the motion and structural information of the *** use polarized optical flow to obtain the optical flow field and estimate the target *** experimental results of different targets under varying water turbidity levels illustrate that our method is realizable and *** precision is verified by comparing the results with the precise displacement data and calculating two error *** proposed method based on polarized optical flow can obtain accurate displacement information and a good recognition *** target segmentation based on the Otsu method further proves the superiority of the polarized optical flow under turbid *** study is valuable for target detection and motion estimation in scattering environments.

关键词： turbid underwater motion estimation polarization imaging optical flow

A new adaptive fast motion estimation algorithm based on local motion similarity degree (LMSD)

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Progress in Natural Science:Materials International 2005年第12期15卷 1126-1134页

作者： LIU Long,HAN Chongzhao and BAI Yan School of Electronics & Information Engineering,Xi’an Jiaotong University,Xi’an 710049,China School of Electronics & Information Engineering Xi''an Jiaotong University Xi''an 710049 China

In the motion vector field adaptive search technique (MVFAST) and the predictive motion vector field adaptive search technique (PMVFAST),the size of the largest motion vector from the three adjacent blocks (left,top,top-right) is compared with the threshold to select different search *** a suitable search center and search pattern will not be selected in the adaptive search technique when the adjacent motion vectors are not coherent in local *** paper presents an efficient adaptive search *** motion vector variation degree (MVVD) is considered a reasonable factor for adaptive search *** the relationship between local motion similarity degree (LMSD) and the variation degree of motion vector (MVVD),the motion vectors are classified as three categories according to corresponding LMSD; then different proposed search schemes are adopted for motion *** experimental results show that the proposed algorithm has a significant computational speedup compared with MVFAST and PMVFAST algorithms,and offers a similar,even better performance.

关键词： motion estimation motion vector video coding local motion