Array cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture images.However,existing so...Array cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture images.However,existing solutions use dense arrays of cameras that require laborious calibration and lack flexibility and practicality.Inspired by the cognition function principle of the human brain,we develop an unstructured array camera system that adopts a hierarchical modular design with multiscale hybrid cameras composing different modules.Intelligent computations are designed to collaboratively operate along both intra-and intermodule pathways.This system can adaptively allocate imagery resources to dramatically reduce the hardware cost and possesses unprecedented flexibility,robustness,and versatility.Large scenes of real-world data were acquired to perform human-centric studies for the assessment of human behaviours at the individual level and crowd behaviours at the population level requiring highresolution long-term monitoring of dynamic wide-area scenes.展开更多
Self-assembled GaN nanorods were grown by metal-organic chemical vapor deposition.A highly regular rosette-shaped cathodoluminescence pattern in the GaN nanorods is observed,where its origin is helpful to deepen the u...Self-assembled GaN nanorods were grown by metal-organic chemical vapor deposition.A highly regular rosette-shaped cathodoluminescence pattern in the GaN nanorods is observed,where its origin is helpful to deepen the understanding of GaN nanorod growth.The pattern forms at the very early stages of nanorod growth,which consists of yellow luminescence at the edges and the non-luminous region at six vertices of the hexagon.To clarify its origin,we carried out detailed cathodoluminescence studies,electron microscopy studies and nanoscale secondary ion mass spectrometry at both the nanorod surface and cross-section.We found the pattern is not related to optical resonance modes or polarity inversion,which are commonly reported in GaN nanostructures.After chemical composition and strain analysis,we found higher carbon and nitrogen cluster concentration and large compressive strain at the pattern area.The pattern formation may relate to facet preferential distribution of non-radiative recombination centers related to excess carbon/nitrogen.This work provides an insight into strain distribution and defect-related emission in GaN nanorod,which is critical for future optoelectronic applications.展开更多
基金the Natural Science Foundation of China(NSFC)under contract No.61860206003,in part by China Postdoctoral Science Foundation No.2020TQ0172 and No.2020M670338in part by the Shenzhen Science and Technology Research and Developm ent Funds(JCYJ20180507183706645).
文摘Array cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture images.However,existing solutions use dense arrays of cameras that require laborious calibration and lack flexibility and practicality.Inspired by the cognition function principle of the human brain,we develop an unstructured array camera system that adopts a hierarchical modular design with multiscale hybrid cameras composing different modules.Intelligent computations are designed to collaboratively operate along both intra-and intermodule pathways.This system can adaptively allocate imagery resources to dramatically reduce the hardware cost and possesses unprecedented flexibility,robustness,and versatility.Large scenes of real-world data were acquired to perform human-centric studies for the assessment of human behaviours at the individual level and crowd behaviours at the population level requiring highresolution long-term monitoring of dynamic wide-area scenes.
基金B.J.Z.would like to thank the China Scholarship Council and the Australia National University for her scholarship supportX.Y.thanks the National Natural Science Foundation of China(Nos.61974166 and 51702368)for financial supportWe would like to thank Dr.Xu Zhang from Zhengzhou University for helpful discussion on some of the strain aspects in this work.
文摘Self-assembled GaN nanorods were grown by metal-organic chemical vapor deposition.A highly regular rosette-shaped cathodoluminescence pattern in the GaN nanorods is observed,where its origin is helpful to deepen the understanding of GaN nanorod growth.The pattern forms at the very early stages of nanorod growth,which consists of yellow luminescence at the edges and the non-luminous region at six vertices of the hexagon.To clarify its origin,we carried out detailed cathodoluminescence studies,electron microscopy studies and nanoscale secondary ion mass spectrometry at both the nanorod surface and cross-section.We found the pattern is not related to optical resonance modes or polarity inversion,which are commonly reported in GaN nanostructures.After chemical composition and strain analysis,we found higher carbon and nitrogen cluster concentration and large compressive strain at the pattern area.The pattern formation may relate to facet preferential distribution of non-radiative recombination centers related to excess carbon/nitrogen.This work provides an insight into strain distribution and defect-related emission in GaN nanorod,which is critical for future optoelectronic applications.
