The accurate measurement of kinematic parameters in satellite separation tests has great significance in evaluating separation performance. A novel study is made on the measuring accuracy of monocular and binocular, w...The accurate measurement of kinematic parameters in satellite separation tests has great significance in evaluating separation performance. A novel study is made on the measuring accuracy of monocular and binocular, which are the two main vision measurement methods used for kinematic parameters. As satellite separation process is transient and high-dynamic, it will bring more extraction errors to the binocular. Based on the design approach of intersection measure and variance ratio, the monocular method reflects higher precision, simpler structure and easier calibration for level satellite separation. In ground separation tests, a high-speed monocular system is developed to gain and analyze twelve kinematic parameters of a small satellite. Research shows that this monocular method can be widely applied for its high precision, with position accuracy of 0.5 mm, speed accuracy of 5 mm/s, and angular velocity accuracy of 1 (°)/s.展开更多
Vehicle anti-collision technique is a hot topic in the research area of Intelligent Transport System. The research on preceding vehicles detection and the distance measurement, which are the key techniques, makes grea...Vehicle anti-collision technique is a hot topic in the research area of Intelligent Transport System. The research on preceding vehicles detection and the distance measurement, which are the key techniques, makes great contributions to safe-driving. This paper presents a method which can be used to detect preceding vehicles and get the distance between own car and the car ahead. Firstly, an adaptive threshold method is used to get shadow feature, and a shadow!area merging approach is used to deal with the distortion of the shadow border. Region of interest(ROI) is obtained using shadow feature. Then in the ROI, symmetry feature is analyzed to verify whether there are vehicles and to locate the vehicles. Finally, using monocular vision distance measurement based on camera interior parameters and geometrical reasoning, we get the distance between own car and the preceding one. Experimental results show that the proposed method can detect the preceding vehicle effectively and get the distance between vehicles accurately.展开更多
单目三维视觉测量在视觉测量领域具有低成本、简便性、结构紧凑等优势,是以智能化、网络化制造为特征的先进制造典型技术之一。经过不断发展,单目三维视觉测量技术已成功应用于无人机导航、智能机器人、工业检测、医疗健康等领域,如今...单目三维视觉测量在视觉测量领域具有低成本、简便性、结构紧凑等优势,是以智能化、网络化制造为特征的先进制造典型技术之一。经过不断发展,单目三维视觉测量技术已成功应用于无人机导航、智能机器人、工业检测、医疗健康等领域,如今呈现出精准化、快捷化、微型化、自动化、动态化等发展趋势。以孔径数量为标准,将单目三维视觉测量技术分为单孔径及多孔径两大类,分别综述两类方法的研究现状和发展历程,重点论述了应用较广的运动恢复结构法(Structure From Motion,SFM)和光场三维测量方法,并对单目三维视觉测量技术的未来方向进行了展望。展开更多
针对目前基于视觉的桥式起重机负载摆角测量方法实时性较低,且没有考虑由运动模糊导致的测量精度下降问题,将一个对旋转和倾斜不敏感的球形标识物安装在负载上,设计一种计算灰度概率分布特征余弦相似度的方法,结合卡尔曼滤波器实时跟踪...针对目前基于视觉的桥式起重机负载摆角测量方法实时性较低,且没有考虑由运动模糊导致的测量精度下降问题,将一个对旋转和倾斜不敏感的球形标识物安装在负载上,设计一种计算灰度概率分布特征余弦相似度的方法,结合卡尔曼滤波器实时跟踪标识物。提出一种基于背景灰度值的局部自适应分割算法,使模糊边缘变清晰。从感兴趣区域(region of interest,ROI)的中心向周围8个方向寻找灰度梯度最大的点作为模糊图像的边缘点,对这些点采用最小二乘法进行拟合确定标识物位置。通过几何关系模型计算负载摆角。实验结果表明,本文方法在图像模糊情况下的测量精度和实时性能更优。展开更多
A new visual measurement method is proposed to estimate three-dimensional (3D) position of the object on the floor based on a single camera. The camera fixed on a robot is in an inclined position with respect to the...A new visual measurement method is proposed to estimate three-dimensional (3D) position of the object on the floor based on a single camera. The camera fixed on a robot is in an inclined position with respect to the floor. A measurement model with the camera's extrinsic parameters such as the height and pitch angle is described. Single image of a chessboard pattern placed on the floor is enough to calibrate the camera's extrinsic parameters after the camera's intrinsic parameters are calibrated. Then the position of object on the floor can be computed with the measurement model. Furthermore, the height of object can be calculated with the paired-points in the vertical line sharing the same position on the floor. Compared to the conventional method used to estimate the positions on the plane, this method can obtain the 3D positions. The indoor experiment testifies the accuracy and validity of the proposed method.展开更多
基金Project(50975280)supported by the National Natural Science Foundation of ChinaProject(NCET-08-0149)supported by Program for New Century Excellent Talents in Universities of China
文摘The accurate measurement of kinematic parameters in satellite separation tests has great significance in evaluating separation performance. A novel study is made on the measuring accuracy of monocular and binocular, which are the two main vision measurement methods used for kinematic parameters. As satellite separation process is transient and high-dynamic, it will bring more extraction errors to the binocular. Based on the design approach of intersection measure and variance ratio, the monocular method reflects higher precision, simpler structure and easier calibration for level satellite separation. In ground separation tests, a high-speed monocular system is developed to gain and analyze twelve kinematic parameters of a small satellite. Research shows that this monocular method can be widely applied for its high precision, with position accuracy of 0.5 mm, speed accuracy of 5 mm/s, and angular velocity accuracy of 1 (°)/s.
基金Key Projects in the Tianjin Science & Technology Pillay Program
文摘Vehicle anti-collision technique is a hot topic in the research area of Intelligent Transport System. The research on preceding vehicles detection and the distance measurement, which are the key techniques, makes great contributions to safe-driving. This paper presents a method which can be used to detect preceding vehicles and get the distance between own car and the car ahead. Firstly, an adaptive threshold method is used to get shadow feature, and a shadow!area merging approach is used to deal with the distortion of the shadow border. Region of interest(ROI) is obtained using shadow feature. Then in the ROI, symmetry feature is analyzed to verify whether there are vehicles and to locate the vehicles. Finally, using monocular vision distance measurement based on camera interior parameters and geometrical reasoning, we get the distance between own car and the preceding one. Experimental results show that the proposed method can detect the preceding vehicle effectively and get the distance between vehicles accurately.
文摘单目三维视觉测量在视觉测量领域具有低成本、简便性、结构紧凑等优势,是以智能化、网络化制造为特征的先进制造典型技术之一。经过不断发展,单目三维视觉测量技术已成功应用于无人机导航、智能机器人、工业检测、医疗健康等领域,如今呈现出精准化、快捷化、微型化、自动化、动态化等发展趋势。以孔径数量为标准,将单目三维视觉测量技术分为单孔径及多孔径两大类,分别综述两类方法的研究现状和发展历程,重点论述了应用较广的运动恢复结构法(Structure From Motion,SFM)和光场三维测量方法,并对单目三维视觉测量技术的未来方向进行了展望。
文摘针对目前基于视觉的桥式起重机负载摆角测量方法实时性较低,且没有考虑由运动模糊导致的测量精度下降问题,将一个对旋转和倾斜不敏感的球形标识物安装在负载上,设计一种计算灰度概率分布特征余弦相似度的方法,结合卡尔曼滤波器实时跟踪标识物。提出一种基于背景灰度值的局部自适应分割算法,使模糊边缘变清晰。从感兴趣区域(region of interest,ROI)的中心向周围8个方向寻找灰度梯度最大的点作为模糊图像的边缘点,对这些点采用最小二乘法进行拟合确定标识物位置。通过几何关系模型计算负载摆角。实验结果表明,本文方法在图像模糊情况下的测量精度和实时性能更优。
基金supported by National Natural Science Foundation of China(Nos.61273352 and 61473295)National High Technology Research and Development Program of China(863 Program)(No.2015AA042307)Beijing Natural Science Foundation(No.4161002)
文摘A new visual measurement method is proposed to estimate three-dimensional (3D) position of the object on the floor based on a single camera. The camera fixed on a robot is in an inclined position with respect to the floor. A measurement model with the camera's extrinsic parameters such as the height and pitch angle is described. Single image of a chessboard pattern placed on the floor is enough to calibrate the camera's extrinsic parameters after the camera's intrinsic parameters are calibrated. Then the position of object on the floor can be computed with the measurement model. Furthermore, the height of object can be calculated with the paired-points in the vertical line sharing the same position on the floor. Compared to the conventional method used to estimate the positions on the plane, this method can obtain the 3D positions. The indoor experiment testifies the accuracy and validity of the proposed method.