To better understand the Paleo-to Mesoproterozoic tectonic evolution of the Dabie Orogen in the northern margin of Yangtze Block,we present geochronological data for metasedimentary and metavolcanic rocks in the Huwan...To better understand the Paleo-to Mesoproterozoic tectonic evolution of the Dabie Orogen in the northern margin of Yangtze Block,we present geochronological data for metasedimentary and metavolcanic rocks in the Huwan complex.A total of 385 detrital zircon LA-ICP-MS analyses for metasedimentary rocks yielded three^(207)Pb/^(206)Pb age populations:1.50-1.80 Ga,1.81-1.87 Ga and 1.93-2.0 Ga,providing a maximum depositional timing of ca.1.50 Ga;while metafelsic volcanic gneisses yielded protolith U-Pb ages of 1893±54 Ma.The peak ages are remarkably consistent with the tectonothermal events that occurred in the northern Yangtze Block,indicating the presence of Paleo-to Mesoproterozoic magmatism in the Dabie Orogen.The age range of 1.93-2.0 Ga correlates with the Paleoproterozoic collision;the age range of 1.81-1.87 Ga coincides with the period of the post-orogenic extension;and the age range of 1.50-1.80 Ga is interpreted to associate with an extensional regime.Zircon cores with age of 1732-1965 Ma haveε_(Hf)(t)values ranging from-11.70 to-2.47,indicating that juvenile crust involved in their magma sources.Owing to the similar age spectra,we proposed that the nucleus of the Dabie Orogen was close to the Yangtze Block since the Paleoproterozoic.The Huwan complex has an intimate affiliation to the Yangtze Block,and implies multiple orogenic cycles.It was not only experienced the Paleo-Tethys ocean subduction and collision,but also recorded Paleo-to Mesoproterozoic tectono-magmatic events in the Dabie Orogen.展开更多
The background models are crucially important for the object extraction for moving objects detection in a video.The Gaussian mixture model(GMM)is one of popular methods in the background models.Gaussian mixture model ...The background models are crucially important for the object extraction for moving objects detection in a video.The Gaussian mixture model(GMM)is one of popular methods in the background models.Gaussian mixture model which applied to the pig target detection has some shortcomings such as low efficiency of algorithm,misjudgment points and ghosts.This study proposed an improved algorithm based on adaptive Gaussian mixture model,to overcome the deficiencies of the traditional Gaussian mixture model in pig object detection.Based on Gaussian mixture background model,this paper introduced two new parameters of video frames m and T0.The Gaussian distribution was scanned once every m frames,the excessive Gaussian distribution was deleted to improve the convergence speed of the model.Meanwhile,using different learning rates to suppress ghosts,a higher decreasing learning rate was adopted to accelerate the background modeling before T_(0),the background model would become stable as the time continued and a smaller learning rate could be used.In order to maintain a stable background and reduce noise interference,a fixed learning rate after T_(0) was used.Results of experiments indicated that this algorithm could quickly build the initial background model,detect the moving target pigs,and extract the complete contours of the target pigs’.The algorithm is characterized by good robustness and adaptability.展开更多
基金granted by National Natural Science Foundation of China(Grant No.42172103)China Geological Survey(DD20221645)Hubei Geological Bureau(KJ2023-11,KCDZ2022-06,KCDZ2023-01)。
文摘To better understand the Paleo-to Mesoproterozoic tectonic evolution of the Dabie Orogen in the northern margin of Yangtze Block,we present geochronological data for metasedimentary and metavolcanic rocks in the Huwan complex.A total of 385 detrital zircon LA-ICP-MS analyses for metasedimentary rocks yielded three^(207)Pb/^(206)Pb age populations:1.50-1.80 Ga,1.81-1.87 Ga and 1.93-2.0 Ga,providing a maximum depositional timing of ca.1.50 Ga;while metafelsic volcanic gneisses yielded protolith U-Pb ages of 1893±54 Ma.The peak ages are remarkably consistent with the tectonothermal events that occurred in the northern Yangtze Block,indicating the presence of Paleo-to Mesoproterozoic magmatism in the Dabie Orogen.The age range of 1.93-2.0 Ga correlates with the Paleoproterozoic collision;the age range of 1.81-1.87 Ga coincides with the period of the post-orogenic extension;and the age range of 1.50-1.80 Ga is interpreted to associate with an extensional regime.Zircon cores with age of 1732-1965 Ma haveε_(Hf)(t)values ranging from-11.70 to-2.47,indicating that juvenile crust involved in their magma sources.Owing to the similar age spectra,we proposed that the nucleus of the Dabie Orogen was close to the Yangtze Block since the Paleoproterozoic.The Huwan complex has an intimate affiliation to the Yangtze Block,and implies multiple orogenic cycles.It was not only experienced the Paleo-Tethys ocean subduction and collision,but also recorded Paleo-to Mesoproterozoic tectono-magmatic events in the Dabie Orogen.
基金supported by the National High Technology Research and Development Program of China(2013AA102306)Independent Innovation Capability of Shandong Province(2014XGA13054).
文摘The background models are crucially important for the object extraction for moving objects detection in a video.The Gaussian mixture model(GMM)is one of popular methods in the background models.Gaussian mixture model which applied to the pig target detection has some shortcomings such as low efficiency of algorithm,misjudgment points and ghosts.This study proposed an improved algorithm based on adaptive Gaussian mixture model,to overcome the deficiencies of the traditional Gaussian mixture model in pig object detection.Based on Gaussian mixture background model,this paper introduced two new parameters of video frames m and T0.The Gaussian distribution was scanned once every m frames,the excessive Gaussian distribution was deleted to improve the convergence speed of the model.Meanwhile,using different learning rates to suppress ghosts,a higher decreasing learning rate was adopted to accelerate the background modeling before T_(0),the background model would become stable as the time continued and a smaller learning rate could be used.In order to maintain a stable background and reduce noise interference,a fixed learning rate after T_(0) was used.Results of experiments indicated that this algorithm could quickly build the initial background model,detect the moving target pigs,and extract the complete contours of the target pigs’.The algorithm is characterized by good robustness and adaptability.
