Before his multi-stop visit to Mexico, Argentina, Peru, Colombia and Jamaica in Latin America and the Caribbean (LAC) early February 2018, then U.S. Secretary of State Rex Tillerson released many signals for Latin A...Before his multi-stop visit to Mexico, Argentina, Peru, Colombia and Jamaica in Latin America and the Caribbean (LAC) early February 2018, then U.S. Secretary of State Rex Tillerson released many signals for Latin America. Especially in his remarks at the University of Texas at Austin, he portrayed the presence of China and Russia in LAC as a "new imperial power" and called on nations of Latin America and the Caribbean to review and reassess China-LAC relations. By identifying China and Russia as critical reference variables for future U.S.- Latin America relations, he obviously went beyond the bilateral level of U.S.- Latin relations and implied the important changes in U.S. policy toward LAC that pressured by growing influence of extra-regional actors in LAC, the United States might strengthen its diplomatic efforts in LAC to maintain and consolidate its dominance in the region.展开更多
For high precision calibration of camera with large field-of-view,massive calibration points will be needed if traditional methods are selected,which makes the calibration complex and time-consuming.In order to solve ...For high precision calibration of camera with large field-of-view,massive calibration points will be needed if traditional methods are selected,which makes the calibration complex and time-consuming.In order to solve this problem,a calibration method based on flexible planar target is proposed.In this method,distortion factor is firstly acquired by the invariance of cross ratio,and existing feature points are adjusted with the distortion factor.Then,a large number of points that will be used for the calibration are constructed with the adjusted feature points.Simultaneously,Tsai method is modified so as to reduce the complexity of calibration,which makes the process linear.The simulation and real experiments show that the method proposed in this paper is simple,linear,accurate and robust,and the precision of this method is close to that of Tsai method using abundant points.The method can satisfy the requirement of high precision calibration for camera with large field-of-view.展开更多
文摘Before his multi-stop visit to Mexico, Argentina, Peru, Colombia and Jamaica in Latin America and the Caribbean (LAC) early February 2018, then U.S. Secretary of State Rex Tillerson released many signals for Latin America. Especially in his remarks at the University of Texas at Austin, he portrayed the presence of China and Russia in LAC as a "new imperial power" and called on nations of Latin America and the Caribbean to review and reassess China-LAC relations. By identifying China and Russia as critical reference variables for future U.S.- Latin America relations, he obviously went beyond the bilateral level of U.S.- Latin relations and implied the important changes in U.S. policy toward LAC that pressured by growing influence of extra-regional actors in LAC, the United States might strengthen its diplomatic efforts in LAC to maintain and consolidate its dominance in the region.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.2014019)
文摘For high precision calibration of camera with large field-of-view,massive calibration points will be needed if traditional methods are selected,which makes the calibration complex and time-consuming.In order to solve this problem,a calibration method based on flexible planar target is proposed.In this method,distortion factor is firstly acquired by the invariance of cross ratio,and existing feature points are adjusted with the distortion factor.Then,a large number of points that will be used for the calibration are constructed with the adjusted feature points.Simultaneously,Tsai method is modified so as to reduce the complexity of calibration,which makes the process linear.The simulation and real experiments show that the method proposed in this paper is simple,linear,accurate and robust,and the precision of this method is close to that of Tsai method using abundant points.The method can satisfy the requirement of high precision calibration for camera with large field-of-view.