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排序方式: 共有227条查询结果,搜索用时 16 毫秒
1.
This paper proposes a new method for self-calibrating a set of stationary non-rotating zooming cameras. This is a realistic configuration, usually encountered in surveillance systems, in which each zooming camera is physically attached to a static structure (wall, ceiling, robot, or tripod). In particular, a linear, yet effective method to recover the affine structure of the observed scene from two or more such stationary zooming cameras is presented. The proposed method solely relies on point correspondences across images and no knowledge about the scene is required. Our method exploits the mostly translational displacement of the so-called principal plane of each zooming camera to estimate the location of the plane at infinity. The principal plane of a camera, at any given setting of its zoom, is encoded in its corresponding perspective projection matrix from which it can be easily extracted. As a displacement of the principal plane of a camera under the effect of zooming allows the identification of a pair of parallel planes, each zooming camera can be used to locate a line on the plane at infinity. Hence, two or more such zooming cameras in general positions allow the obtainment of an estimate of the plane at infinity making it possible, under the assumption of zero-skew and/or known aspect ratio, to linearly calculate the camera's parameters. Finally, the parameters of the camera and the coordinates of the plane at infinity are refined through a nonlinear least-squares optimization procedure. The results of our extensive experiments using both simulated and real data are also reported in this paper. 相似文献
2.
《Advanced Robotics》2012,26(23):1225-1234
Recently, the demand for more accurate, productive, and economical robot manipulators is increasing in the robotics industry. However, a manipulator will produce kinematic errors during production. Thus low-cost kinematic calibration is demanded. Moreover, environmental mapping is also demanded to plan the motions of the manipulator. In this paper, we proposed a simultaneous kinematic calibration, localization, and mapping (SKCLAM) method, which can simultaneously calibrate the kinematic parameters of an industrial robot manipulator using a commercial RGB-D camera attached to its end effector to reconstruct its surroundings. In our method, the kinematic calibration is achieved with feature detection and epipolor geometry. Synthetic and real data experiments were conducted to verify the SKCLAM method. We succeeded in reducing the kinematic errors of the manipulator and reconstructing dense 3D maps of the workspace in the experiments. 相似文献
3.
This paper aims to evaluate the impacts of speed limit enforcement cameras on reducing road accidents in the UK by accounting for both confounding factors and the selection of proper reference groups. The propensity score matching (PSM) method is employed to do this. A naïve before and after approach and the empirical Bayes (EB) method are compared with the PSM method. A total of 771 sites and 4787 sites for the treatment and the potential reference groups respectively are observed for a period of 9 years in England. Both the PSM and the EB methods show similar results that there are significant reductions in the number of accidents of all severities at speed camera sites. It is suggested that the propensity score can be used as the criteria for selecting the reference group in before-after control studies. Speed cameras were found to be most effective in reducing accidents up to 200 meters from camera sites and no evidence of accident migration was found. 相似文献
4.
Jun-Sik Kim Myung Hwangbo Takeo Kanade 《Computer Vision and Image Understanding》2010,114(10):1068-1083
Estimating motions of a multi-camera system which may not have overlapping fields of view is generally complex and computationally expensive because of the non-zero offset between each camera’s center. It is conceivable that if we can assume that multiple cameras share a single optical center, and thus can be modeled as a spherical imaging system, motion estimation and calibration of this system would become simpler and more efficient. 相似文献
5.
The existence of space charge may be addressed as one of the reasons that could cause shielding failure of transmission lines. In order to study the effect of s... 相似文献
6.
Tsong-Tseh Tsay Richard Inman Barnaby Wray Brian Herman Ken Jacobson 《Journal of microscopy》1990,160(2):141-159
The use of low-light-level video cameras and solid-state image detectors in conjunction with image digitizers for optical microscopy is increasing dramatically as more people learn about such systems, and as they become more powerful, less expensive, and easier to use. However, there is currently little information available allowing comparison between cameras, or for determining camera suitability for a given experiment. In this paper, we describe a series of tests designed to characterize the performance of low-light-level cameras. The results of these tests should assist in the selection of appropriate cameras for given video microscopy applications. 相似文献
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《Journal of Visual Communication and Image Representation》2014,25(4):599-621
This paper presents a novel flexible architecture for 3DTV based on multiple uncalibrated cameras. The proposed signal representation improves the interactivity of dense point-based methods, making them appropriate for modeling the scene semantics and free-viewpoint 3DTV applications. The main concern is to address the shortcomings of depth image-based 3D video systems for free-viewpoint visualization, and to provide an efficient implementation of the rendering part which is computationally intensive as well potentially determine the view quality. Novel rendering algorithms are added that specifically aim at solving the rendering artifacts, and sampling issues encountered in wide baseline extensions and arbitrary camera movements. To optimize the process, a “selective” warping technique is proposed that takes the advantage of temporal coherence to reduce the computational overhead. Performance is illustrated on challenging videos to prove the suitability and flexibility of the architecture for advanced 3DTV systems. 相似文献