共查询到18条相似文献,搜索用时 187 毫秒
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一种基于灰度投影与块匹配的视频序列快速稳像算法 总被引:4,自引:2,他引:2
针对视频图像序列的不稳定性,结合灰度投影算法与块匹配法各自的特点,提出了一种可以快速消除图像序列间平移和旋转抖动的新型电子稳像算法.该算法首先采用灰度投影法估计与补偿图像序列间的平移运动,然后用拉普拉斯算子在图像边缘处选取灰度信息比较丰富的小块模板,利用块匹配法计算模板的平移运动,再结合模板在图像上的位置估计图像的旋转... 相似文献
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从序列图象获取运动刚体的三维信息是计算机视觉学中一项很有意义的工作。本文提出了在两种运动分解形式下的刚体运动方程,论述了刚体运动参数和三维坐标的求解问题,建立了一种求解旋转矩阵R的新算法,该算法是线性的。因而与已有的算法相比,它的计算简单、计算量小,便于实时处理。所附算例证明了本算法稳定性优于已有算法,计算精度有所提高。 相似文献
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从两幅透视图像恢复被摄目标的三维结构是计算机视觉最基本的任务之一,其中,运动估计算法的性能决定了最终的三维重建精度。首先讨论了双视成像的基本数学模型,并介绍了几种现有运动参数估计方法的基本原理和不足。随后,基于投影误差最小判决函数,提出了用于双像运动估计的改进非线性迭代优化方法。数值仿真结果表明,在大平移小旋转角及小平移大旋转角2种运动条件下,采用文中提出的方法,运动估计精度均有所提高。此外,根据运动参数的估计值对真实目标进行三维重建实验,结果表明尺度重建误差小于2%且角度误差在3°以内。 相似文献
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从正投影光流场计算刚体运动参数和结构 总被引:1,自引:0,他引:1
从光流场恢复刚体三维运动和结构是计算机视觉中一个基本问题。本文研究从正投影光流场恢复刚体三维运动和结构问题,建立了光流运动方程,提出一种判别多个光流点是否共面或是否属于同一刚体的有效方法。证明了平移运动刚体有两个自由度,旋转运动刚体有一个自由度,一般运动刚体有三个自由度,至少需要四个光流点才能获得一般运动刚体的流参数(含一比例因子)。 相似文献
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角振幅的图像测量方法 总被引:1,自引:0,他引:1
将时间平均成像方法用于谐波角振动物体的振幅测量。采用该方法只需用普通的CCD摄像机分别摄取被测物体的静态下在图像及其在谐波振动状态下的一幅时间平均成像,即可求得该物体的角振幅。为求解该问题所导出的非线性方程,本文构造了基于图像相关的迭代算法。实验表明该测量方法具有较高的精度和工程可用性,且对实验设备和测量环境要求不高,很适合现场测量。 相似文献
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L. L. Yaw N. Sukumar S. K. Kunnath 《International journal for numerical methods in engineering》2009,79(8):979-1003
In this paper, a meshfree co‐rotational formulation for two‐dimensional continua is proposed. In a co‐rotational formulation, the motion of a body is separated into rigid motion and strain‐producing deformation. Traditionally, this has been done in the setting of finite elements for beams and shell‐type elements. In the present work every node in a meshfree discretized domain has its own co‐rotating coordinate system. Three key ingredients are established in order to apply the co‐rotational formulation: (i) the relationship between global and local variables, (ii) the angle of rotation of a typical co‐rotating coordinate system, and (iii) a variationally consistent tangent stiffness matrix. An algorithm for the co‐rotational formulation based on load control is provided. Maximum‐entropy basis functions are used to discretize the domain and stabilized nodal integration is implemented to construct the global system of equations. Numerical examples are presented to demonstrate the validity of the meshfree co‐rotational formulation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Chia-Hung Chen 《中国工程学刊》2013,36(5):638-646
A robust and accurate method for estimating the 3-D pose of a planar rigid object is presented. This article demonstrates that 3-D pose estimation becomes feasible by using the 2-D tracking points on an object of scale-invariant feature transform (SIFT) and 3-D point cloud detected by stereo vision on an object, assuming that a 3-D geometric model of an object is known a priori. The roll and pitch angles of an object are estimated by the normal vector of approximate plane of 3-D point cloud on an object and the yaw angle is estimated by 2-D tracking point on an object of SIFT. Accurate object detection and localization in the camera coordinate system is crucial for grasping. In the motion planning, the bidirectional rapidly exploring random tree algorithm is used to search for a valid path for efficient grasping. Our robot arm can robustly and autonomously grasp a randomly rotative rigid object detected by SIFT in 3-D space. We have realized a grasping scenario with a dexterous arm (ADAM) such that an object in front of ADAM can be grasped. This demonstration shows how the proposed components build a dexterous and robust system integrating object detection, pose estimation, and motion planning. 相似文献
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Mun K. Leung Thomas S. Huang 《International journal of imaging systems and technology》1992,4(2):80-97
We propose a motion estimation system that uses stereo image pairs as the input data. To perform experimental work, we also obtain a sequence of outdoor stereo images taken by two metric cameras. The system consists of four main stages, which are (1) determination of point correspondences on the stereo images, (2) correction of distortions in image coordinates, (3) derivation of 3D point coordinates from 2D correspondences, and (4) estimation of motion parameters based on 3D point correspondences. For the first stage of the system, we use a four-way matching algorithm to obtain matched point on two stereo image pairs at two consecutive time instants (ti and ti + 1). Since the input data are stereo images taken by cameras, it has two types of distortions, which are (i) film distortion and (ii) lens distortion. These two distortions must be corrected before any process can be applied on the matched points. To accomplish this goal, we use (i) bilinear transform for film distortion correction and (ii) lens formulas for lens distortion correction. After correcting the distortions, the results are 2D coordinates of each matched point that can be used to derive 3D coordinates. However, due to data noise, the calculated 3D coordinates to not usually represent a consistent rigid structure that is suitable for motion estimation; therefore, we suggest a procedure to select good 3D point sets as the input for motion estimation. The procedure exploits two constraints, rigidity between different time instants and uniform point distribution across the object on the image. For the last stage, we use an algorithm to estimate the motion parameters. We also wish to know what is the effect of quantization error on the estimated results; therefore an error analysis based on quantization error is performed on the estimated motion parameters. In order to test our system, eight sets of stereo image pairs are extracted from an outdoor stereo image sequence and used as the input data. The experimental results indicate that the proposed system does provide reasonable estimated motion parameters. 相似文献
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H. A. Attia 《Acta Mechanica》2001,149(1-4):11-21
Summary In the present paper, a numerical method for generating the equations of motion of planar mechanisms with only revolute joints is presented. The method rests upon the idea of replacing the rigid body by a dynamically equivalent constrained system of particles. For the open loop case, the equations of motion are generated recursively along the open chains. Geometric constraints that fix the distance between the particles are introduced. For the closed loop case, the system is transformed to open loops by cutting suitable kinematic joints with the addition of kinematic constraints. The method is conceptually easy and suitable for computer implementation. It eliminates the necessity of distributing the external forces and moments over the particles and uses the concepts of linear and angular momentums to generate the rigid body equations of motion without introducing any rotational coordinates. An example with closed loops is chosen to demonstrate the generality and simplicity of the proposed method. 相似文献
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提高彩色大面阵航空遥感相机地面分辨力需设计像移补偿环节以消除工作时CCD像面的像移,本文在分析航空遥感器4种像移补偿方式及像移补偿机构设计原则的基础上,针对某航空遥感器的要求设计了一种前向像移补偿机构,利用等径共轭凸轮机构将电机旋转转化为直线运动,并配合精密直线导轨约束运动自由度。具有传动简单,精度较高的优点,可有效的避免传动误差。分析了原动件输入速度波动、制造误差对像移补偿残差的影响,并对像移补偿总体效果进行了评价。试验数据及数据分析表明,像移补偿机构的补偿残差小到600μm/s,动态目标发生器及外场航拍图像良好,满足使用要求。 相似文献