An efficient vehicle detection approach is proposed for traffic surveillance images, which is based on information fusion of vehicle symmetrical contour and license plate position. The vertical symmetry axis of the ve...An efficient vehicle detection approach is proposed for traffic surveillance images, which is based on information fusion of vehicle symmetrical contour and license plate position. The vertical symmetry axis of the vehicle contour in an image is. first detected, and then the vertical and the horizontal symmetry axes of the license plate are detected using the symmetry axis of the vehicle contour as a reference. The vehicle location in an image is determined using license plate symmetry axes and the vertical and the horizontal projection maps of the vehicle edge image. A dataset consisting of 450 images （15 classes of vehicles） is used to test the proposed method. The experimental results indicate that compared with the vehicle contour-based, the license plate location-based, the vehicle texture-based and the Gabor feature-based methods, the proposed method is the best with a detection accuracy of 90.7% and an elapsed time of 125 ms.展开更多
In Guangxi, the Lower-Middle Devonian boundary beds yield abundant corals, brachiopods,stromatoporoids and conodonts. The former three were common in tropical and subtropical zones, while thelast occurred only round t...In Guangxi, the Lower-Middle Devonian boundary beds yield abundant corals, brachiopods,stromatoporoids and conodonts. The former three were common in tropical and subtropical zones, while thelast occurred only round the equator. This reveals that the South China Plate in the Early-Middle Devonianwas at or near the equator, which was also supported by palaeomagnetic study giving the palaeolatitude of theGuangxi Region at the time to be 0°36′N.展开更多
A numerical study of natural convection in an enclosure containing an eccentrically positioned inclined flat plate is performed,and the impact of eccentricity and inclination angle on flow and heat transfer are analyz...A numerical study of natural convection in an enclosure containing an eccentrically positioned inclined flat plate is performed,and the impact of eccentricity and inclination angle on flow and heat transfer are analyzed using a finite-difference code.The effect of eccentricity on the convection mechanism in the large and small spaces separated by the plate is explored,as well as the way in which the deviation between the directions of the plate and the buoyancy force determines the fluid motion.It is found that the total heat transfer exhibits a dramatic increase as the normalized eccentricity reaches e/D=0.3,namely,by 21.2%,13.4%,and 20.5%at α=0°,90°,and 180°,respectively,compared with the e/D=0.2 case,owing to the enhanced heat transfer by conduction,which dominates the local flow and heat transfer in the small region between the plate and the enclosure.When the plate is inclined,primary,secondary,and tertiary vortices are generated in the two halves of the enclosure,and the intensity of the vortices increases as they approach the horizontal centerline.Analysis of the local heat transfer demonstrates that the maximum local heat transfer rate occurs either at the top of the enclosure owing to natural convection or at the position close to the end of the plate,where conduction dominates.展开更多
基金The National Natural Science Foundation of China(No. 40804015,61101163)
文摘An efficient vehicle detection approach is proposed for traffic surveillance images, which is based on information fusion of vehicle symmetrical contour and license plate position. The vertical symmetry axis of the vehicle contour in an image is. first detected, and then the vertical and the horizontal symmetry axes of the license plate are detected using the symmetry axis of the vehicle contour as a reference. The vehicle location in an image is determined using license plate symmetry axes and the vertical and the horizontal projection maps of the vehicle edge image. A dataset consisting of 450 images （15 classes of vehicles） is used to test the proposed method. The experimental results indicate that compared with the vehicle contour-based, the license plate location-based, the vehicle texture-based and the Gabor feature-based methods, the proposed method is the best with a detection accuracy of 90.7% and an elapsed time of 125 ms.
基金The study was supported by the National Natural Science Foundaion of China the State Education Commission of China.
文摘In Guangxi, the Lower-Middle Devonian boundary beds yield abundant corals, brachiopods,stromatoporoids and conodonts. The former three were common in tropical and subtropical zones, while thelast occurred only round the equator. This reveals that the South China Plate in the Early-Middle Devonianwas at or near the equator, which was also supported by palaeomagnetic study giving the palaeolatitude of theGuangxi Region at the time to be 0°36′N.
文摘A numerical study of natural convection in an enclosure containing an eccentrically positioned inclined flat plate is performed,and the impact of eccentricity and inclination angle on flow and heat transfer are analyzed using a finite-difference code.The effect of eccentricity on the convection mechanism in the large and small spaces separated by the plate is explored,as well as the way in which the deviation between the directions of the plate and the buoyancy force determines the fluid motion.It is found that the total heat transfer exhibits a dramatic increase as the normalized eccentricity reaches e/D=0.3,namely,by 21.2%,13.4%,and 20.5%at α=0°,90°,and 180°,respectively,compared with the e/D=0.2 case,owing to the enhanced heat transfer by conduction,which dominates the local flow and heat transfer in the small region between the plate and the enclosure.When the plate is inclined,primary,secondary,and tertiary vortices are generated in the two halves of the enclosure,and the intensity of the vortices increases as they approach the horizontal centerline.Analysis of the local heat transfer demonstrates that the maximum local heat transfer rate occurs either at the top of the enclosure owing to natural convection or at the position close to the end of the plate,where conduction dominates.
