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In this study, tennis ball rotation and trajectory are analyzed quantitatively. Fourteen dots are marked on a tennis ball to detect the ball rotation, and the markers' x−y positions are detected from high-speed camera images. First, the 3-D positions of the markers are calculated. Then, the rotation matrix is calculated by using the 3-D marker positions of successive camera frames. The rotation parameters,...
Environmental change is a growing international concern, calling for the regular monitoring, studying and preserving of detailed information about the evolution of underwater ecosystems. For example, fragile coral reefs are exposed to various sources of hazards and potential destruction, and need close observation. Computer vision offers promising technologies to build 3D models of an environment...
The position of a world point's solar shadow depends on its geographical location, the geometrical relationship between the orientation of the sunshine and the ground plane where the shadow casts. This paper investigates the property of solar shadow trajectories on a planar surface and shows that camera parameters, latitude, longitude can be estimated from two observed shadow trajectories. Our contribution...
This paper introduces a synchronization methodology for distributed vision based sensor networks with clock skew or variable frame rates. The methodology requires a ballistic or otherwise predictive object to be tracked by the sensor network and used to calibrate the clock skew and/or relative variable frame rates between the cameras. The relative time stamp of each image captured can be extracted...
This paper describes a vision system to obtain the 3D trajectory of a moving target by stereovision. For our study, we chose to reconstruct the trajectory of a clay plate that is used in ball-trap. The plate's path can reach 60 meters in length. The trajectory is reconstructed from videos of the moving target and plate positions between the left and right images at different times. To find the 3D...
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