To solve the problem of insufficient ability when detecting the high-speed moving target with passive millimeter wave technology, a direct-detection passive millimeter wave detecting system using the monolithic microw...To solve the problem of insufficient ability when detecting the high-speed moving target with passive millimeter wave technology, a direct-detection passive millimeter wave detecting system using the monolithic microwave integrated cir- cuit （MMIC） millimeter wave radiometer is built, and the measured data are obtained by experiment under different condi- tions. Based on feature analysis of testing signals, it points out that the peak of the first pulse and interval of two peak pulses are valid features which can reflect the motion characteristic of target. A method to calculate the moving speed of target is put forward. The calculating results indicate that the proposed method has enough accuracy and is feasible to determine the parameters of the moving target using for passive millimeter wave system.展开更多
Vehicle detectition in still images is a comparatively difficult task. This paper presents a method for this task by using boosted local pattern detector constructed from two local features including Haar-like and ori...Vehicle detectition in still images is a comparatively difficult task. This paper presents a method for this task by using boosted local pattern detector constructed from two local features including Haar-like and oriented gradient features. The whole process is composed of three stages. In the first stage, local appearance features of vehicles and non-vehicle objects are extracted. Haar-tike and oriented gradient features are extracted separately in this stage as local features. In the second stage, Adabeost algorithm is used to select the most discriminative features as weak detectors from the two local feature sets, and a strong local pattern detector is built by the weighted combination of these selected weak detectors. Finally, vehicle detection can be performed in still images by using the boosted strong local feature detector. Experiment results show that the local pattern detector constructed in this way combines the advantages of Haar-like and oriented gradient features, and can achieve better detection results than the detector by using single Haar-like features.展开更多
This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to ...This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to obtain an eddy dataset from 21 years of satellite altimeter data. Analysis revealed that the number of anticyclonic eddies was nearly equal to cyclonic eddies; in the SCS,cyclonic eddies are generally stronger than anticyclonic eddies and anticyclonic eddies are larger and longer-lived than cyclonic eddies. Anticyclonic eddies tend to survive longer in the spring and summer,while cyclonic eddies have longer lifetimes in the autumn and winter. The characteristics and seasonal variations of eddies in the SCS are strongly related to variations in general ocean circulation,in the homogeneity of surface wind stress,and in the unevenness of bottom topography in the SCS. The spatial and temporal variation of mesoscale eddies in the SCS could,therefore,be an important index for understanding local hydrodynamics and regional climate change.展开更多
文摘To solve the problem of insufficient ability when detecting the high-speed moving target with passive millimeter wave technology, a direct-detection passive millimeter wave detecting system using the monolithic microwave integrated cir- cuit （MMIC） millimeter wave radiometer is built, and the measured data are obtained by experiment under different condi- tions. Based on feature analysis of testing signals, it points out that the peak of the first pulse and interval of two peak pulses are valid features which can reflect the motion characteristic of target. A method to calculate the moving speed of target is put forward. The calculating results indicate that the proposed method has enough accuracy and is feasible to determine the parameters of the moving target using for passive millimeter wave system.
基金supported by the Korea Research Foundation Grant funded by the Korean Government(MOEHRD),the MKE(The Ministry of Knowledge Economy,Korea)the ITRC(Information Technology Research Center)support program(NIPA-2009-(C1090-0902-0007))
文摘Vehicle detectition in still images is a comparatively difficult task. This paper presents a method for this task by using boosted local pattern detector constructed from two local features including Haar-like and oriented gradient features. The whole process is composed of three stages. In the first stage, local appearance features of vehicles and non-vehicle objects are extracted. Haar-tike and oriented gradient features are extracted separately in this stage as local features. In the second stage, Adabeost algorithm is used to select the most discriminative features as weak detectors from the two local feature sets, and a strong local pattern detector is built by the weighted combination of these selected weak detectors. Finally, vehicle detection can be performed in still images by using the boosted strong local feature detector. Experiment results show that the local pattern detector constructed in this way combines the advantages of Haar-like and oriented gradient features, and can achieve better detection results than the detector by using single Haar-like features.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2013AA09A505)the National Natural Science Foundation of China(No.U1133001)the NSFC-Shandong Joint Fund for Marine Science Research Centers Grant(No.U1406401)
文摘This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to obtain an eddy dataset from 21 years of satellite altimeter data. Analysis revealed that the number of anticyclonic eddies was nearly equal to cyclonic eddies; in the SCS,cyclonic eddies are generally stronger than anticyclonic eddies and anticyclonic eddies are larger and longer-lived than cyclonic eddies. Anticyclonic eddies tend to survive longer in the spring and summer,while cyclonic eddies have longer lifetimes in the autumn and winter. The characteristics and seasonal variations of eddies in the SCS are strongly related to variations in general ocean circulation,in the homogeneity of surface wind stress,and in the unevenness of bottom topography in the SCS. The spatial and temporal variation of mesoscale eddies in the SCS could,therefore,be an important index for understanding local hydrodynamics and regional climate change.
