The emission wavelength of InGaN/GaN dot-in-wire LED can be tuned by modifying the nanowire diameter,but it causes mismatched angular distributions between blue,green,and red nanowires because of the excitation of dif...The emission wavelength of InGaN/GaN dot-in-wire LED can be tuned by modifying the nanowire diameter,but it causes mismatched angular distributions between blue,green,and red nanowires because of the excitation of different waveguide modes.Besides,the far-field radiation patterns and light extraction efficiency are typically calculated by center dipoles,which fails to provide accurate results.To address these issues,we first compare the simulation results between central dipole and dipole cloud with experimental data.Next,we calculate and analyze the display metrics for full-color nanowire LEDs by 3D dipole cloud.Finally,we achieve unnoticeable angular color shift within±20°viewing cone for augmented reality(AR)and virtual reality(VR)displays with an improved light extraction efficiency.展开更多
To improve the segmentation quality and efficiency of color image,a novel approach which combines the advantages of the mean shift(MS) segmentation and improved ant clustering method is proposed.The regions which can ...To improve the segmentation quality and efficiency of color image,a novel approach which combines the advantages of the mean shift(MS) segmentation and improved ant clustering method is proposed.The regions which can preserve the discontinuity characteristics of an image are segmented by MS algorithm,and then they are represented by a graph in which every region is represented by a node.In order to solve the graph partition problem,an improved ant clustering algorithm,called similarity carrying ant model(SCAM-ant),is proposed,in which a new similarity calculation method is given.Using SCAM-ant,the maximum number of items that each ant can carry will increase,the clustering time will be effectively reduced,and globally optimized clustering can also be realized.Because the graph is not based on the pixels of original image but on the segmentation result of MS algorithm,the computational complexity is greatly reduced.Experiments show that the proposed method can realize color image segmentation efficiently,and compared with the conventional methods based on the image pixels,it improves the image segmentation quality and the anti-interference ability.展开更多
文摘The emission wavelength of InGaN/GaN dot-in-wire LED can be tuned by modifying the nanowire diameter,but it causes mismatched angular distributions between blue,green,and red nanowires because of the excitation of different waveguide modes.Besides,the far-field radiation patterns and light extraction efficiency are typically calculated by center dipoles,which fails to provide accurate results.To address these issues,we first compare the simulation results between central dipole and dipole cloud with experimental data.Next,we calculate and analyze the display metrics for full-color nanowire LEDs by 3D dipole cloud.Finally,we achieve unnoticeable angular color shift within±20°viewing cone for augmented reality(AR)and virtual reality(VR)displays with an improved light extraction efficiency.
基金Project(60874070) supported by the National Natural Science Foundation of China
文摘To improve the segmentation quality and efficiency of color image,a novel approach which combines the advantages of the mean shift(MS) segmentation and improved ant clustering method is proposed.The regions which can preserve the discontinuity characteristics of an image are segmented by MS algorithm,and then they are represented by a graph in which every region is represented by a node.In order to solve the graph partition problem,an improved ant clustering algorithm,called similarity carrying ant model(SCAM-ant),is proposed,in which a new similarity calculation method is given.Using SCAM-ant,the maximum number of items that each ant can carry will increase,the clustering time will be effectively reduced,and globally optimized clustering can also be realized.Because the graph is not based on the pixels of original image but on the segmentation result of MS algorithm,the computational complexity is greatly reduced.Experiments show that the proposed method can realize color image segmentation efficiently,and compared with the conventional methods based on the image pixels,it improves the image segmentation quality and the anti-interference ability.
