We explore the spin–orbit coupling(SOC) mechanism for structured light in coherent atomic media with low-light-level cross-Kerr nonlinearity. Using the five-level M-type electromagnetic induced transparency(EIT) syst...We explore the spin–orbit coupling(SOC) mechanism for structured light in coherent atomic media with low-light-level cross-Kerr nonlinearity. Using the five-level M-type electromagnetic induced transparency(EIT) system as a prototype, we show that spin–orbit splitting for a weak spinor image can be generated by a weak trigger field carrying orbital angular momentum(OAM) at low-light intensity. By quantum-optical analogy, the paraxial focusing and defocusing of the two pseudo-spin states in the spinor image can be governed by a Pauli-like equation. More importantly, by changing the EIT parameters, especially the topological charge of the weak trigger field, the SOC-induced radial quantization of the spinor image can be rather significant,giving rise to positive or negative OAM-OAM mode separation in free space. This suggests that the separation can be flexibly controlled due to strong image-vortex interaction based on fewphoton cross-Kerr modulation. Our findings may have the potential for all-optical OAM multiplexing and demultiplexing of structured light fields toward few-photon quantum control and multimode communication.展开更多
A novel frame shift and integral technique for the enhancement of low light level moving image sequence is introduced. According to the technique, motion parameters of target are measured by algorithm based on differe...A novel frame shift and integral technique for the enhancement of low light level moving image sequence is introduced. According to the technique, motion parameters of target are measured by algorithm based on difference processing. To obtain spatial relativity, images are shifted according to the motion parameters. As a result, the processing of integral and average can be applied to images that have been shifted. The technique of frame shift and integral that includes the algorithm of motion parameter determination is discussed, experiments with low light level moving image sequences are also described. The experiment results show the effectiveness and the robustness of the parameter determination algorithm, and the improvement in the signal-to-noise ratio （SNR） of low light level moving images.展开更多
For better night-vision applications using the low-light-level visible and infrared imaging, a fusion framework for night-vision context enhancement（FNCE） method is proposed. An adaptive brightness stretching method...For better night-vision applications using the low-light-level visible and infrared imaging, a fusion framework for night-vision context enhancement（FNCE） method is proposed. An adaptive brightness stretching method is first proposed for enhancing the visible image. Then, a hybrid multi-scale decomposition with edge-preserving filtering is proposed to decompose the source images. Finally, the fused result is obtained via a combination of the decomposed images in three different rules. Experimental results demonstrate that the FNCE method has better performance on the details（edges）, the contrast, the sharpness, and the human visual perception. Therefore,better results for the night-vision context enhancement can be achieved.展开更多
电子轰击型有源像素传感器(Electron Bombarded Active Pixel Sensor,EBAPS)作为一种数字化微光成像器件,以其成像系统具有小型化、低成本和低功耗的优势,以及在昼夜条件下连续拍摄时具备清晰成像的能力,成为微光成像领域的研究热点。...电子轰击型有源像素传感器(Electron Bombarded Active Pixel Sensor,EBAPS)作为一种数字化微光成像器件,以其成像系统具有小型化、低成本和低功耗的优势,以及在昼夜条件下连续拍摄时具备清晰成像的能力,成为微光成像领域的研究热点。文章基于国产某型EBAPS微光器件,利用FPGA作为核心处理器,完成了EBAPS器件驱动电路、图像处理和跟踪电路、显示电路的设计。同时,构建了满足昼夜复用的光学系统,搭建了一种小型化的手持成像跟踪系统。实验结果表明,该EBAPS昼夜成像系统可在1×10^(-4)~1×10^(4) lx照度条件下实现良好的成像和跟踪效果。展开更多
近视患病率逐年攀升,已成为全球性的重大公共卫生问题之一。目前的近视防控措施,如角膜塑形镜、离焦框架眼镜、软性离焦角膜接触镜、低浓度阿托品滴眼液均存在不足之处。重复低强度红光(RLRL)近年来成为儿童近视控制的手段之一。多项临...近视患病率逐年攀升,已成为全球性的重大公共卫生问题之一。目前的近视防控措施,如角膜塑形镜、离焦框架眼镜、软性离焦角膜接触镜、低浓度阿托品滴眼液均存在不足之处。重复低强度红光(RLRL)近年来成为儿童近视控制的手段之一。多项临床研究结果均表明,RLRL照射能够抑制儿童青少年近视的快速增长。近期一篇研究报告"Cone Density Changes After Repeated Low-Level Red Light Treatment in Children With Myopia"(《重复低强度红光治疗后近视儿童的视锥细胞密度变化》),在近视儿童的家长中引起了广泛讨论。本文详细分析此文章研究方法及结果,探讨是否能得出RLRL会影响近视儿童黄斑视锥细胞密度的结论。展开更多
使用范围综述的研究方法系统分析光生物调节疗法(photobiomodulation,PBM)在帕金森病(Parkinson disease,PD)患者中的临床应用,总结治疗方案、结局指标和疗效,为后续的临床研究和治疗提供参考。本文检索Web of Science、PubMed、Embase...使用范围综述的研究方法系统分析光生物调节疗法(photobiomodulation,PBM)在帕金森病(Parkinson disease,PD)患者中的临床应用,总结治疗方案、结局指标和疗效,为后续的临床研究和治疗提供参考。本文检索Web of Science、PubMed、Embase、Cochrane Library、中国知网和万方数据库,最终共纳入13项研究。结果发现PBM治疗能够有效改善PD患者的运动症状、非运动症状以及大脑结构,可以作为传统治疗的有益补充。但是大样本的随机对照试验研究仍然较少,选用的治疗参数也存在较大差异,因此还需要开展大规模、长时间的研究来进一步探究其疗效。展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.11574016 and 11204154)。
文摘We explore the spin–orbit coupling(SOC) mechanism for structured light in coherent atomic media with low-light-level cross-Kerr nonlinearity. Using the five-level M-type electromagnetic induced transparency(EIT) system as a prototype, we show that spin–orbit splitting for a weak spinor image can be generated by a weak trigger field carrying orbital angular momentum(OAM) at low-light intensity. By quantum-optical analogy, the paraxial focusing and defocusing of the two pseudo-spin states in the spinor image can be governed by a Pauli-like equation. More importantly, by changing the EIT parameters, especially the topological charge of the weak trigger field, the SOC-induced radial quantization of the spinor image can be rather significant,giving rise to positive or negative OAM-OAM mode separation in free space. This suggests that the separation can be flexibly controlled due to strong image-vortex interaction based on fewphoton cross-Kerr modulation. Our findings may have the potential for all-optical OAM multiplexing and demultiplexing of structured light fields toward few-photon quantum control and multimode communication.
文摘A novel frame shift and integral technique for the enhancement of low light level moving image sequence is introduced. According to the technique, motion parameters of target are measured by algorithm based on difference processing. To obtain spatial relativity, images are shifted according to the motion parameters. As a result, the processing of integral and average can be applied to images that have been shifted. The technique of frame shift and integral that includes the algorithm of motion parameter determination is discussed, experiments with low light level moving image sequences are also described. The experiment results show the effectiveness and the robustness of the parameter determination algorithm, and the improvement in the signal-to-noise ratio （SNR） of low light level moving images.
基金supported by the National Natural Science Foundation of China(No.61231014)the Foundation of Army Armaments Department of China(No.6140414050327)the Foundation of Science and Technology on Low-Light-Level Night Vision Laboratory(No.BJ2017001)
文摘For better night-vision applications using the low-light-level visible and infrared imaging, a fusion framework for night-vision context enhancement（FNCE） method is proposed. An adaptive brightness stretching method is first proposed for enhancing the visible image. Then, a hybrid multi-scale decomposition with edge-preserving filtering is proposed to decompose the source images. Finally, the fused result is obtained via a combination of the decomposed images in three different rules. Experimental results demonstrate that the FNCE method has better performance on the details（edges）, the contrast, the sharpness, and the human visual perception. Therefore,better results for the night-vision context enhancement can be achieved.
文摘近视患病率逐年攀升,已成为全球性的重大公共卫生问题之一。目前的近视防控措施,如角膜塑形镜、离焦框架眼镜、软性离焦角膜接触镜、低浓度阿托品滴眼液均存在不足之处。重复低强度红光(RLRL)近年来成为儿童近视控制的手段之一。多项临床研究结果均表明,RLRL照射能够抑制儿童青少年近视的快速增长。近期一篇研究报告"Cone Density Changes After Repeated Low-Level Red Light Treatment in Children With Myopia"(《重复低强度红光治疗后近视儿童的视锥细胞密度变化》),在近视儿童的家长中引起了广泛讨论。本文详细分析此文章研究方法及结果,探讨是否能得出RLRL会影响近视儿童黄斑视锥细胞密度的结论。
文摘使用范围综述的研究方法系统分析光生物调节疗法(photobiomodulation,PBM)在帕金森病(Parkinson disease,PD)患者中的临床应用,总结治疗方案、结局指标和疗效,为后续的临床研究和治疗提供参考。本文检索Web of Science、PubMed、Embase、Cochrane Library、中国知网和万方数据库,最终共纳入13项研究。结果发现PBM治疗能够有效改善PD患者的运动症状、非运动症状以及大脑结构,可以作为传统治疗的有益补充。但是大样本的随机对照试验研究仍然较少,选用的治疗参数也存在较大差异,因此还需要开展大规模、长时间的研究来进一步探究其疗效。
