【作者】 王小立；

【导师】 龚卫国；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2010， 硕士

【摘要】 目前,电子稳像技术EIS(Electronic Image Stabilization)是视频处理、计算机视觉等领域的研究热点。由于具有稳像精度高、体积小、重量轻、功耗低以及成本低等优点,它在军事和民用领域中都有着非常广阔的应用前景。电子稳像的关键技术包括运动估计和运动补偿,其中,序列帧间的运动估计是电子稳像的基础。因此人们进行了大量的研究,提出了多种不同的运动估计算法。本论文在分析各经典算法优劣的基础上,对电子稳像的各项关键技术进行了研究和探讨,并提出一种基于特征匹配的电子稳像算法,具有一定学术价值与实用价值。主要研究内容概括如下:①本论文对电子稳像技术的国内外研究进展及常用方法进行回顾和总结。阐述了电子稳像的基本原理、基本方法和处理过程,并讨论了其实现的关键技术。介绍了电子稳像中几种常见的典型算法,分析了各算法的优缺点。着重指出,由于能够处理图像序列帧间的复杂运动,基于特征的方法是电子稳像的重要算法。本论文就是采用基于特征的方法。②运动估计是通过对图像进行分析,估算摄像机的全局运动参数。如何提高运动估计的效率和精度是电子稳像技术研究的重点。本论文针对摄像机在复杂运动环境中的视频稳定,提出一种基于边缘图像配准的高精度电子稳像方法。该方法首先同时检测图像的边缘和边缘上的角点特征;然后,利用匹配点对引导边缘匹配,并筛选适量分布均匀的匹配点对求取初始全局运动估计;最后,改进粒子滤波器以对边缘图像进行配准来获得精确全局运动参数,进一步提高了运动估计的精度。③对于存在自主扫描的稳像系统,首先要判断并分离摄像机的自主扫描和随机抖动。本论文根据Kalman滤波的基本原理,结合所提出的图像数学模型,设计出对摄像机全局运动矢量进行平滑以分离抖动和自主扫描的Kalman滤波器。实验结果表明该方法在去除高频抖动的同时能较好地保留摄像机的自主扫描。④针对图像抖动补偿后产生的“未定义区域”,分析了传统的处理方法——图像裁剪和拼接的各自特点。本论文将图像拼接技术用于“未定义区域”的重建。该方法解决了“未定义区域”造成的信息丢失和图像降质问题,提高了图像序列的视觉效果。本论文最后介绍了电子稳像技术的评价指标,对实际拍摄的视频图像进行了稳像实验,并对稳像效果进行了分析。实验结果证明了所提出稳像算法的有效性。更多还原

【Abstract】 Currently, the technology of EIS is an important research area of video processing and computer vision. Because of its advantages of high image stabilizing precision, compact size, lightweight, low power consumption and reasonable price, it will have extensive application prospect in military affairs and civil cameras. The key technology of the EIS includes motion estimation and motion compensation, and the motion estimation between adjacent frames is the foundation of EIS. Thus, a lot of research are carried out and several algorithms of motion estimation are proposed. Basing on the analysis on advantages and shortcomings of the typical algorithms, the key technology of EIS is discussed and an algorithm based on feature registration is presented. The proposed algorithm is both of academic value and practical value. The main research works in this thesis are as follows:①The research progress at home and abroad and the common methods of EIS are reviewed and summarized. In this thesis, the basic principles, methods and process of the electronic image stabilization are described, and the key technology of the realization is discussed. Several typical algorithms of EIS and their advantages and shortcomings are introduced and analyzed. It emphatically points out that the algorithm based on feature matching is considered as the important method, because of its perfect performance to deal with the complex dither between image frames. And this kind of algorithm is used in the thesis.②The object of motion estimation is to analyze the adjacent frames and estimate the motion parameter of the camera. How to improve the efficiency and accuracy of the motion estimation is the research emphasis. In order to keep the video stream stable when the camera works in complex movement state, a high-accuracy electronic image stabilization method based on edge image registration is presented. In the proposed method, edge feature and corner are detected from the frames at the same time. Matched points are then utilized to guide edge matching, and a proper number of well distributed corresponding points are selected to get initial global motion estimation. Finally, to obtain accurate global motion parameters, improved particle filter is applied to edge image registration to further improve the image stabilization precision.③When the movement of the camera include random jitter and intentional motion, we must distinguish them firstly. According to the basic principle of Kalman filter and the mathematical model proposed in the thesis, a Kalman filter used to distinguish camera scan from dithering by smoothing the global motion vector are designed. Experimental results show that the method can not only alleviate the vibration but also can preserve the initiative scan of the camera.④Image tailoring and mosaic are often used to reconstruct the undefined regions which generated after the dither image compensated. The thesis analyses the respective characteristics of them. And the image mosaic is used to reconstruct the undefined regions. This method solves the common problems of information loss and image degradation brought by the undefined regions, and also improves the visual effect of the image sequence.Evaluation indexes of the EIS are introduced at the end of the thesis and several image stabilization experiments have been carried out with the video image sequence taken by hand-held camera. In addition, the stabilization effect is evaluated. The simulation and experimental rusults demonstrated that this method of EIS proposed in the thesis is feasible.更多还原