共查询到19条相似文献,搜索用时 78 毫秒
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传统的相机的畸变校正方法都需要人工干预不能直接计算,即需要事先放置特定的标定参照物或人工指定对应信息。文章提出了一种基于旋转运动视频序列的多帧对齐,可直接计算相机的径向畸变参数。给出了旋转运动参数模型和对齐多帧图像的优化函数以计算畸变参数,推导了目标函数的线性化公式,然后用阻尼最小二乘法优化计算径向畸变参数和旋转运动场参数。试验显示它对变形图像能给出很好的校正。 相似文献
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H.264中多参考帧预测技术的优化 总被引:1,自引:0,他引:1
提出了一个低复杂度的快速多参考帧选择算法。模拟结果表明本算法在保持率失真性能的前提下可以大大减少多参考帧预测的计算复杂度。 相似文献
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基于H.264的多参考帧运动估计快速算法 总被引:1,自引:0,他引:1
H.264/AVC中引入多参考帧运动补偿来提高视频编码性能,由此产生的多参考帧运动估计(MRF-ME)却带来了巨大的运算代价。为提高编码速度,降低计算复杂度,提出一种基于空间域相关性的运动估计算法——缩小的菱形算法(DDS)。先运用前向主矢量选择法不断修正预测运动矢量,再根据最佳参考帧位置的统计特性对不同参考帧使用不用模板进行搜索。实验结果表明,与H.264参考模型JM10.2相比,该算法保持了较好的图像质量且码率变化很小,运动搜索点数平均减少接近80%,并能有效地降低编码器复杂度。 相似文献
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摄像机的运动信息是视像内容检索中的一种重要特征。文中介绍了两种基于全局运动的摄像机运动检测方案。首先提取视像中的运动特征作为原始数据,然后分别使用了迭代最小二乘法和支持向量机分类的方法进行摄像机运动的检测,通过对试验结果的对比,前一种方案可更有效地完成摄像机运动类型的判断。 相似文献
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徐淑平 《计算机技术与发展》2007,17(7):1-3,12
摄像机的运动信息是视像内容检索中的一种重要特征。文中介绍了两种基于全局运动的摄像机运动检测方案。首先提取视像中的运动特征作为原始数据,然后分别使用了迭代最小二乘法和支持向量机分类的方法进行摄像机运动的检测,通过对试验结果的对比,前一种方案可更有效地完成摄像机运动类型的判断。 相似文献
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In this paper, we propose a global method for estimating the motion of a camera which films a static scene. Our approach is
direct, fast and robust, and deals with adjacent frames of a sequence. It is based on a quadratic approximation of the deformation
between two images, in the case of a scene with constant depth in the camera coordinate system. This condition is very restrictive
but we show that, provided translation and depth inverse variations are small enough, the error on optical flow involved by
the approximation of depths by a constant is small. In this context, we propose a new model of camera motion which allows
to separate the image deformation in a similarity and a “purely” projective application, due to change of optical axis direction.
This model leads to a quadratic approximation of image deformation that we estimate with an M-estimator; we can immediately
deduce camera motion parameters.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
相似文献
G. KoepflerEmail: |
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We present a fast, robust algorithm for multi-frame structure from motion from point features which works for general motion and large perspective effects. The algorithm is for point features but easily extends to a direct method based on image intensities. Experiments on synthetic and real sequences show that the algorithm gives results nearly as accurate as the maximum likelihood estimate in a couple of seconds on an IRIS 10000. The results are significantly better than those of an optimal two-image estimate. When the camera projection is close to scaled orthographic, the accuracy is comparable to that of the Tomasi/Kanade algorithm, and the algorithms are comparably fast. The algorithm incorporates a quantitative theoretical analysis of the bas-relief ambiguity and exemplifies how such an analysis can be exploited to improve reconstruction. Also, we demonstrate a structure-from-motion algorithm for partially calibrated cameras, with unknown focal length varying from image to image. Unlike the projective approach, this algorithm fully exploits the partial knowledge of the calibration. It is given by a simple modification of our algorithm for calibrated sequences and is insensitive to errors in calibrating the camera center. Theoretically, we show that unknown focal-length variations strengthen the effects of the bas-relief ambiguity. This paper includes extensive experimental studies of two-frame reconstruction and the Tomasi/Kanade approach in comparison to our algorithm. We find that two-frame algorithms are surprisingly robust and accurate, despite some problems with local minima. We demonstrate experimentally that a nearly optimal two-frame reconstruction can be computed quickly, by a minimization in the motion parameters alone. Lastly, we show that a well known problem with the Tomasi/Kanade algorithm is often not a significant one. 相似文献
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为了解当前数字视频稳像中相机运动估计技术的发展现状、存在问题和发展前景,对其进行了研究。通过对相关文献的归纳和分析,将新兴数字视频稳像中相机运动估计技术分为3D运动估计、传感器辅助运动估计以及新兴2D运动估计,并分别讨论了各种运动估计技术的研究现状、研究成果、不足和挑战。最后,结合技术和市场因素对数字视频稳像中相机运动估计技术的发展前景进行了展望。研究表明,当前数字视频稳像中相机运动估计技术在实时应用和估计精度上都有待改善。 相似文献
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通过给摄像机平移、旋转与变焦等运动建模,并把运动模型与基于象素点亮度变化的方法相结合来估计
摄像机运动参数。用得到的运动参数可以把视频构造成一幅全景图,全景图可广泛应用于视频压缩与检索。实验表
明,该方法可成功地应用于视频会议系统中的视频压缩与视频检索。 相似文献
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通过给摄像机平移、旋转与变焦等运动建模,并把运动模型与基于象素点亮度变化的方法相结合来估计摄像机运动参数。用得到的运动参数可以把视频构造成一幅全景图,全景图可广泛应用于视频压缩与检索。实验表明,该方法可成功地应用于视频会议系统中的视频压缩与视频检索。 相似文献
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In this paper we show how to carry out an automatic alignment of a pan-tilt camera platform with its natural coordinate frame,
using only images obtained from the cameras during controlled motion of the unit. An active camera in aligned orientation
represents the zero position for each axis, and allows axis odometry to be referred to a fixed reference frame; such referral
is otherwise only possible using mechanical means, such as end-stops, which cannot take account of the unknown relationship
between the camera coordinate frame and its mounting. The algorithms presented involve the calculation of two-view transformations
(homographies or epipolar geometry) between pairs of images related by controlled rotation about individual head axes. From
these relationships, which can be calculated linearly or optimised iteratively, an invariant line to the motion can be extracted
which represents an aligned viewing direction. We present methods for general and degenerate motion (translating or non-translating),
and general and degenerate scenes (non-planar and planar, but otherwise unknown), which do not require knowledge of the camera
calibration, and are resistant to lens distortion non-linearity.Detailed experimentation in simulation, and in real scenes,
demonstrate the speed, accuracy, and robustness of the methods, with the advantages of applicability to a wide range circumstances
and no need to involve calibration objects or complex motions. Accuracy of within half a degree can be achieved with a single
motion, and we also show how to improve on this by incorporating images from further motions, using a natural extension of
the basic algorithm. 相似文献
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Ameesh Makadia Christopher Geyer Kostas Daniilidis 《International Journal of Computer Vision》2007,75(3):311-327
We present a novel approach for the estimation of 3D-motion directly from two images using the Radon transform. The feasibility
of any camera motion is computed by integrating over all feature pairs that satisfy the epipolar constraint. This integration
is equivalent to taking the inner product of a similarity function on feature pairs with a Dirac function embedding the epipolar
constraint. The maxima in this five dimensional motion space will correspond to compatible rigid motions. The main novelty
is in the realization that the Radon transform is a filtering operator: If we assume that the similarity and Dirac functions
are defined on spheres and the epipolar constraint is a group action of rotations on spheres, then the Radon transform is
a correlation integral. We propose a new algorithm to compute this integral from the spherical Fourier transform of the similarity
and Dirac functions. Generating the similarity function now becomes a preprocessing step which reduces the complexity of the
Radon computation by a factor equal to the number of feature pairs processed. The strength of the algorithm is in avoiding
a commitment to correspondences, thus being robust to erroneous feature detection, outliers, and multiple motions.
The authors are grateful for support through the following grants: NSF-IIS-0083209, NSF-IIS-0121293, NSF-EIA-0324977, NSF-CNS-0423891,
NSF-IIS-0431070, and ARO/MURI DAAD19-02-1-0383.
The author is grateful for the generous support of the ARO MURI program (DAAD-19-02-1-0383) while at U. C. Berkeley. 相似文献