In model-based computer vision, the fundamental difficulty in recognizing objects from images is that the appearance of a shape depends on the viewpoint. This problem is entirely avoided if the geometric description o...In model-based computer vision, the fundamental difficulty in recognizing objects from images is that the appearance of a shape depends on the viewpoint. This problem is entirely avoided if the geometric description of the object is unaffected by the imaging transformations. This description is an invdriant. Four commonly used planar projective invariants encountered in practical applications are discussed and their reliability is illustrated experimentally.They are analyzed from a theoretical viewpoint to derive expressions which characterize the propagation of error and from an experimental viempoint by constructing some test patterns with known values of the invariants and comparing these values with those calculated from the image data. An algorithm using invariant to recognize objects under projection is also introduced. It is found that the accuracy and stability of the invariants are directly dependent on the performance of the feature extraction scheme employed to recover the test pattern geometry from the images.展开更多
The construction of wind power project is conducive to saving energy,reducing emissions and regulating energy structure. But it inevitably causes some impacts on the environment in the construction process. Because th...The construction of wind power project is conducive to saving energy,reducing emissions and regulating energy structure. But it inevitably causes some impacts on the environment in the construction process. Because that the height of wind power generator generally exceeds 100 m,and visual range in plain region is farther,it is necessary to scientifically and rationally evaluate and analyze landscape visual environment impact of wind power generator in plain region. One wind power farm project of Zhanjiang is located in typical plain region of Guangdong coast. Referring to traditional analytic method of landscape visual impact and comparing with actual situation for the same kind of project in the region,results show that it is ＂ extremely sensitive＂ area at 0- 2. 5 km from wind power generator, ＂ very sensitive＂ area at 2. 5- 5. 0 km, ＂ sensitive＂ area at 5- 10 km, ＂generally sensitive＂ area at 10- 20 km,and non-sensitive area outside 20 km.展开更多
文摘In model-based computer vision, the fundamental difficulty in recognizing objects from images is that the appearance of a shape depends on the viewpoint. This problem is entirely avoided if the geometric description of the object is unaffected by the imaging transformations. This description is an invdriant. Four commonly used planar projective invariants encountered in practical applications are discussed and their reliability is illustrated experimentally.They are analyzed from a theoretical viewpoint to derive expressions which characterize the propagation of error and from an experimental viempoint by constructing some test patterns with known values of the invariants and comparing these values with those calculated from the image data. An algorithm using invariant to recognize objects under projection is also introduced. It is found that the accuracy and stability of the invariants are directly dependent on the performance of the feature extraction scheme employed to recover the test pattern geometry from the images.
文摘The construction of wind power project is conducive to saving energy,reducing emissions and regulating energy structure. But it inevitably causes some impacts on the environment in the construction process. Because that the height of wind power generator generally exceeds 100 m,and visual range in plain region is farther,it is necessary to scientifically and rationally evaluate and analyze landscape visual environment impact of wind power generator in plain region. One wind power farm project of Zhanjiang is located in typical plain region of Guangdong coast. Referring to traditional analytic method of landscape visual impact and comparing with actual situation for the same kind of project in the region,results show that it is ＂ extremely sensitive＂ area at 0- 2. 5 km from wind power generator, ＂ very sensitive＂ area at 2. 5- 5. 0 km, ＂ sensitive＂ area at 5- 10 km, ＂generally sensitive＂ area at 10- 20 km,and non-sensitive area outside 20 km.
