共查询到20条相似文献,搜索用时 203 毫秒
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《光子学报》2017,(2)
针对逆向工程中引导性曲面边界信息的快速获取问题,系统地研究了共轴立体视觉测量方法,建立该方法的数学模型,详细分析了摄像机焦距、基线距等系统结构参数及被测点空间位置对测量精度的影响,通过数学分析确定摄像机基线距的最佳取值范围,研究共轴立体视觉测量系统特殊的极线几何关系.提出基于共轴立体视觉的曲面边界快速测量方法,利用三坐标测量机的精密机械系统及精确的空间定位能力,用单个摄像机以两次共轴定位摄取图像的方式实现共轴立体视觉测量功能,然后利用共轴立体视觉外极线相互平行且通过各自像平面主点的特殊极线几何关系简化同源像点匹配过程,从而快速获取被测曲面的边界信息.实验结果表明:用基于三坐标测量机的单摄像机共轴立体视觉测量方法获取的曲面边界平均误差为0.268mm,基本满足逆向工程中对引导性曲面边界的测量精度要求. 相似文献
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面向大视场视觉测量的摄像机标定技术 总被引:7,自引:0,他引:7
提出了一种面向大视场高精度视觉测量的摄像机标定新方法,该方法采用亮度自适应的单个红外发光二极管(IR-LED)作为目标靶点,将该靶点固定在三坐标测量机的测头上,并依次精确移动至预先设定的空间位置,每次靶点到达设定的空间位置时,摄像机对靶点进行图像采集。利用三坐标测量机的精确位移,在三维空间构成一个虚拟立体靶标。针对虚拟立体靶标在大视场摄像机标定中只能覆盖一小部分标定空间的问题,通过自由移动摄像机在多个方位对虚拟立体靶标进行拍摄,使得多个虚拟立体靶标分布于整个标定空间。摄像机在每个方位对虚拟立体靶标的拍摄都标定出一组摄像机的内、外参数,然后以摄像机内参数和摄像机在各个方位下拍摄的虚拟立体靶标在摄像机坐标系下的位置及姿态参数为优化变量,建立以所有三维靶点位置重投影误差平方和为最小的目标函数,采用非线性优化方法求解摄像机标定参数的最优解。该方法较好地解决了大视场视觉测量中大尺寸靶标加工困难、摄像机标定精度难以保证的问题。仿真和实际标定实验均证明此方法可以有效提高大视场摄像机的标定精度。 相似文献
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大尺度三维几何尺寸立体视觉测量系统实现 总被引:15,自引:2,他引:15
基于立体视觉的大尺度三维几何尺寸测量技术是对外形不规则的大型物体进行几何量测量的有效方法。与传统的视觉测量技术不同,大尺度视觉测量的精度随测量距离的增加而迅速下降,同时大尺度空间下照明条件难以控制,也使得测量变得不稳定。因此如何在大测量尺度的前提下提高测量精度成为这一领域的研究难点。从立体视觉测量系统的原理出发,分析了影响系统精度的各种因素,将相位一致性变换与极线约束条件引入结构光光条中心提取之中,显著提高了图像分析的精度。研制了测量系统的样机并给出了实验结果,现场测试表明该系统可以有效地保证大尺度条件下的测量精度。 相似文献
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针对现有用于光学测量的双目变焦系统标定方法难度大、测量精度受限于两摄像机内参一致性等问题。提出一种基于单摄像机的平行双目立体视觉系统实现及其高精度变焦标定方法。方法基于三角测量原理采集图像,利用高精度位移台驱动单摄像机进行平移以保证基线精度;求解离散焦距下的预标定结果并利用BP神经网络模型对其进行拟合,以实现任意焦距下系统内外参数动态估计。实验结果表明,系统预标定的重投影误差小于0.1664 pixel,变焦后图像畸变校正平均误差为0.0982 pixel,立体视觉测量尺寸绝对误差小于0.05mm。方法能弥补传统变焦标定方法的不足,消除双目内参不一致引入的误差,提高视觉系统的测量精度。 相似文献
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基于光学参考棒的立体视觉测量系统现场标定技术 总被引:9,自引:5,他引:4
为实现大空间复杂工件的准确测量,精确标定立体视觉系统变得越来越重要。为了克服传统立体摄像机标定过程繁复、户外实现困难的弱点,提出了一种基于光学参考棒的灵活、有效的立体视觉测量系统标定技术。参考棒水平和深度方向各有三个距离已知的红外LED作为特征点。通过在测量范围内的不同位置和方位移动光学参考棒,两像机同时捕获参考棒上特征点的图像。基于匹配的特征像点以及对极线约束,利用线性算法和Levenberg-Marquardt(LM)迭代算法快速地标定立体视觉测量系统。两像机之间平移量的比例因子由参考棒上特征点间的已知距离确定。参量标定过程中,自动地控制光强,优化曝光时间,使不同位置处光点图像的强度均一致,可以获得高的信噪比,提高标定精度。实验结果表明,该方法灵活、有效,在线标定能达到很高的精度,将现场标定过程应用到实际的大空间三维测量系统中,测量最大误差为0.18 mm。 相似文献
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3D metrology of a stereovision system requires epipolar rectification to be performed before dense stereo matching. In this study, we propose an epipolar rectification method for a stereovision system with two telecentric lens-based cameras. Given the orthographic projection matrices of each camera, the new projection matrices are computed by determining the new camera coordinates system in affine space and imposing some constraints on the intrinsic parameters. Then, the transformation that maps the old image planes on to the new image planes is achieved. Experiments are performed to validate the performance of the proposed rectification method. The test results show that the perpendicular distance and 3D reconstructed deviation obtained from the rectified images is not significantly higher than the corresponding values obtained from the original images. Considering the roughness of the extracted corner points and calibrated camera parameters, we can conclude that the proposed method can provide sufficiently accurate rectification results. 相似文献
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In this paper, a new opto-digital stereo object tracking system using the variable window mask and the optical binary phase extraction joint transform correlator (BPEJTC) is proposed. At the first step, with the distance information from the stereo camera to the tracking object easily acquired by the structural elements of a stereo vision system, the area of the tracking object can be digitally extracted by using the variable window mask. And, at the second step, by carrying out the optical BPEJTC between this reference image obtained from the variable window mask and the stereo input image, the coordinates of the tracking object's location can be acquired, and then with these values, the convergence angle and the pan/tilt of the stereo tracking camera can be finally controlled. From some experimental results, the proposed system is found to be able to effectively extract the area of the target object from the input image having the background noises by using the variable window mask. And, with the location values of the tracking object obtained by using the optical BPEJTC, the convergence angle and the pan/tilt of the stereo cameras can be controlled. Finally, a feasibility of real-time implementation of the adaptive stereo object tracking system using the proposed algorithm is also suggested. 相似文献
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Jung-Hwan Ko 《Optics Communications》2006,266(1):67-79
In this paper, a novel stereoscopic video surveillance system to track a target person and detect its three-dimensional (3D) location coordinates and moving trajectory is implemented by using the pan/tilt-controlled stereo camera system. Stereoscopic video images of a target person are captured with stereo camera system and the target face and its location in the left image plane can be detected by use of YCbCr color model and centroid method. Also the target location in the right image plane can be obtained through correlation between the left face image and the right image by using the binary phase extraction joint transform correlator (BPEJTC) algorithm. With these location data of the target face in the left and right image planes the pan/tilt systems can control the stereo camera to track a target person by positioning the target face at the center of the camera’s FOV and making the focusing points of the right and left camera coincided on the target face. And then, with the resultant pan/tilt angles and geometric parameters of the stereo camera system, the target’s real 3D location coordinates and moving trajectory in the world space can be obtained. From some experiments with 900 frames of stereoscopic video image pairs, it is analyzed that the target’s center location after being tracked is kept to be very low error ratio of 0.62%, 2.04% on the average in the x, y directions of the image plane, respectively. Also, the error ratio between the calculated and measured values of the 3D location coordinates of a target person is found to be very low value of 2.1%, 5.7% on the average in the X and Y directions of the real world space, respectively. 相似文献
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We propose a new method, based on the depth-from-defocus technique and binocular vision, for solving the stereo particle pairing problem in 3D particle tracking velocimetry (PTV). Firstly, the apparent particle depth is measured with a single camera, using the depth-from-defocus technique. Secondly, a strict mathematical model of the particle-to-particle correspondence relationship between the left and right images, taking into account the refractions at the interfaces in the optical path, is presented, with the assumption that the apparent particle depth is measured. Thirdly, based on the apparent particle depth and particle-to-particle correspondence relationship, the epipoplar line is truncated into a short line segment by cutting off, where the apparent particle depth extends beyond its estimated range. For the first time, the range of the blur circle radius is employed as an additional stereo particle pairing constraint. Finally, the optimal pairing particle is selected by applying the epipolar line segment and blur circle radius constraints. The experimental results show that the rate of correct pairing is significantly improved compared with the epipolar line nearest neighbor analysis, especially when the particle density is increasing. 相似文献
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Shape measurement by a multi-view methodology based on the remote tracking of a 3D optical scanner 总被引:4,自引:0,他引:4
Sandro Barone Alessandro Paoli Armando Viviano Razionale 《Optics and Lasers in Engineering》2012,50(3):380-390
Full field optical techniques can be reliably used for 3D measurements of complex shapes by multi-view processes, which require the computation of transformation parameters relating different views into a common reference system. Although, several multi-view approaches have been proposed, the alignment process is still the crucial step of a shape reconstruction.In this paper, a methodology to automatically align 3D views has been developed by integrating a stereo vision system and a full field optical scanner. In particular, the stereo vision system is used to remotely track the optical scanner within a working volume. The tracking system uses stereo images to detect the 3D coordinates of retro-reflective infrared markers rigidly connected to the scanner. Stereo correspondences are established by a robust methodology based on combining the epipolar geometry with an image spatial transformation constraint.The proposed methodology has been validated by experimental tests regarding both the evaluation of the measurement accuracy and the 3D reconstruction of an industrial shape. 相似文献
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单目多视点立体图像提取及应用 总被引:1,自引:0,他引:1
设计并实现了一种基于广角相机和平面镜的单目多视点立体图像摄像系统,给出了硬件装置的设计指标和优化方法;同时,在研究了硬件系统的标定方法基础上,实现了其在三维测距方面的应用。多枚平面镜构成的对称斗型腔体被放置在广角相机前面,物体光线经过不同平面镜反射后,投影到相机图像平面的不同区域,在相机投影平面上生成物体多个影像,形成单目多视点投影图像。该类图像等价于视点不同的多幅图像,可以使用多视点立体视觉算法实现三维测量。 相似文献
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单摄像机虚拟立体视觉测量技术研究 总被引:6,自引:0,他引:6
以双目立体视觉传感器三维测量模型为基础,提出了一种用于测量空间三维点坐标的低成本单摄像机模型。该模型利用光学成像,把单摄像机镜像为一对虚拟摄像机,在一个CCD像面上采集到同一物体存在视差的两幅图像,从而恢复空间点的三维信息。讨论了单摄像机传感器测量空间三维点坐标的基本原理,建立了单摄像机传感器的测量模型,克服了双摄像机系统中成本高、切换采集左右摄像机的图像使检测速度减慢等诸多缺陷,为空间三维点的精密测量提供了经济、快速、有效的测量途径。实验表明.传感器可实现约0.8%的相对测量精度.证明了本方案合理、有效。 相似文献