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Simulation of Quantum Noise in the Low-Light-Level Imaging System 被引量:3
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作者 邹正峰 芦汉生 +1 位作者 白廷柱 高稚允 《Journal of Beijing Institute of Technology》 EI CAS 2001年第2期186-190,共5页
A mathematical model of quantum noise having much effect on the low light imaging system is set up. To simulate the quantum noise, the random numbers obeying noise distribution must be formed and are weighted on the... A mathematical model of quantum noise having much effect on the low light imaging system is set up. To simulate the quantum noise, the random numbers obeying noise distribution must be formed and are weighted on the basis of the model created. Three uniform random sequences are built by the linear congruential method, of which two are used to form integer number and decimal fraction parts of the new random sequence respectively and the third to shuffle the new sequence. And then a Gauss sequence is formed out of uniform distribution by a function transforming method. It actualizes the simulation in real time of quantum noise in the low light imaging system, where video flow is extracted in real time, the noise summed up and played back side by side with the original video signs by a simulation software. 展开更多
关键词 SIMULATION quantum noises low light level imaging
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Anthropogenic activity,hydrological regime,and light level jointly influence temporal patterns in biosonar activity of the Yangtze finless porpoise at the junction of the Yangtze River and Poyang Lake,China
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作者 Peng-Xiang Duan Zhi-Tao Wang +4 位作者 Tomonari Akamatsu Nick Tregenza Guang-Yu Li Ke-Xiong Wang Ding Wang 《Zoological Research》 SCIE CSCD 2023年第5期919-931,共13页
Under increasing anthropogenic pressure,species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations.The critically endangered Yangtze finless porpoise(Neopho... Under increasing anthropogenic pressure,species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations.The critically endangered Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),once commonly observed in the Yangtze River-Poyang Lake junction,is now rarely seen in the river-lake corridor.In this study,static passive acoustic monitoring techniques were used to detect the biosonar activities of the Yangtze finless porpoise in this unique corridor.Generalized linear models were used to examine the correlation between these activities and anthropogenic impacts from the COVID-19 pandemic lockdown and boat navigation,as well as environmental variables,including hydrological conditions and light levels.Over approximately three consecutive years of monitoring(2020–2022),porpoise biosonar was detected during 93%of logged days,indicating the key role of the corridor for finless porpoise conservation.In addition,porpoise clicks were recorded in 3.80%of minutes,while feeding correlated buzzes were detected in 1.23%of minutes,suggesting the potential existence of localized,small-scale migration.Furthermore,both anthropogenic and environmental variables were significantly correlated with the diel,lunar,monthly,seasonal,and annual variations in porpoise biosonar activities.During the pandemic lockdown period,porpoise sonar detection showed a significant increase.Furthermore,a significant negative correlation was identified between the detection of porpoise click trains and buzzes and boat traffic intensity.In addition to water level and flux,daylight and moonlight exhibited significant correlations with porpoise biosonar activities,with markedly higher detections at night and quarter moon periods.Ensuring the spatiotemporal reduction of anthropogenic activities,implementing vessel speed restrictions(e.g.,during porpoise migration and feeding),and maintaining local natural hydrological regimes are critical factors for sustaining porpoise population viability. 展开更多
关键词 Yangtze finless porpoises Yangtze River Poyang Lake Pandemic lockdown Boat traffic Hydrological regime light level
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Effective Dose Screening of Low Level Red Light in Different Cell Indexes
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作者 Qiu Shuting Pan Zhi +3 位作者 Jiang Xiao Hu Fan Zhang Hao Wu Fengjuan 《China Detergent & Cosmetics》 CAS 2023年第3期41-50,共10页
The low level red light irradiation dose that produced positive response on different cell indexes was selected through experiments.In fibroblast detection model,the low level red light irradiation dose that had posit... The low level red light irradiation dose that produced positive response on different cell indexes was selected through experiments.In fibroblast detection model,the low level red light irradiation dose that had positive response to the four indicators of mitochondrial membrane potential,ATP release,cell migration and collagen synthesis was screened.The experimental results showed that low level red light with a irradiation dose of 2 J/cm^(2) had a positive response to the above four indexes in fibroblast.The test model on fibroblast was later transferred to dermal papilla cells for further experimental verification.The results showed that low level red light with a irradiation dose of 2 J/cm^(2) also had a positive response to the four indicators of dermal papilla cells,namely,mitochondrial membrane potential,ATP release,cell proliferation rate and collagen synthesis.It is proved that the low level red light with a irradiation dose of 2 J/cm^(2) could improve the mitochondrial function,cell migration and collagen synthesis of fibroblast and dermal papilla cell,thus providing energy for cell activities,improving cell repair ability and cell anti-aging ability. 展开更多
关键词 low level red light dose screening mitochondrial function collagen synthesis cell migration
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Novel Frame Shift and Integral Technique for Enhancing Low-Light-Level Moving Images
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作者 宋勇 郝群 王涌天 《Journal of Beijing Institute of Technology》 EI CAS 2006年第1期91-96,共6页
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
关键词 frame integral low light level image moving image sequence signal-to-noise ratio (SNR)
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基于LightTools软件的微光光学系统杂散光分析 被引量:3
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作者 朱佳丽 张平 +5 位作者 李刚 韦湘宜 费程波 干杰 袁玉芬 季亚萍 《应用光学》 CAS CSCD 北大核心 2022年第6期1061-1065,共5页
为解决低照度微弱信号探测的微光光学系统杂散光问题,研究了杂散光的原理和特性。利用光学系统建模软件LightTools对微光光学系统进行仿真建模,并开展杂散光分析。为减少杂散光,在物镜筒的筒壁加工消光螺纹,并针对不同形式的消光螺纹,... 为解决低照度微弱信号探测的微光光学系统杂散光问题,研究了杂散光的原理和特性。利用光学系统建模软件LightTools对微光光学系统进行仿真建模,并开展杂散光分析。为减少杂散光,在物镜筒的筒壁加工消光螺纹,并针对不同形式的消光螺纹,开展了能量仿真模拟。仿真结果表明,采用螺距0.35 mm的消光螺纹,能够将杂散光系数从7%降低到4%。仿真分析结果与实验结果一致,为其他微弱信号探测光学系统在设计阶段对杂散光进行消除提供了指导。 展开更多
关键词 杂散光 微光光学系统 消光螺纹 lightTools软件
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MTF Measurement of EBCCD Imaging System by Using Super Resolution Technique
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作者 左昉 高岳 +2 位作者 高稚允 苏美开 周立伟 《Journal of Beijing Institute of Technology》 EI CAS 2003年第2期125-128,共4页
Existing methods of measurement MTF for discrete imaging system are analysed. A slit target is frequently used to measure the MTF for an imaging system. Usually there are four methods to measure the MTF for a discrete... Existing methods of measurement MTF for discrete imaging system are analysed. A slit target is frequently used to measure the MTF for an imaging system. Usually there are four methods to measure the MTF for a discrete imaging system by using a slit. These methods have something imperfect respectively. But for the discrete imaging systems of under sampling it is difficult to reproduce this type of target properly since frequencies above Nyquist are folded into those below Nyquist, resulting in aliasing effect. To tackle the aliasing problem, a super resolution technique is introduced into our measurement, which gives MTF values both above and below Nyquist more accurately. 展开更多
关键词 EBCCD modulation transfer function super resolution low light level imaging
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矿用LED多媒体信息发布系统研究与设计
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作者 赵云龙 《煤炭技术》 CAS 2024年第11期242-246,共5页
针对煤矿井下普遍存在多种监测监控系统数据利用率低、井下安全教育形式单一匮乏、井下逃生指引及交通调度指引智能化水平低等问题,提出一种基于矿用LED拼接屏和本安型声光报警器的多媒体信息发布系统设计方案。该信息发布系统可根据客... 针对煤矿井下普遍存在多种监测监控系统数据利用率低、井下安全教育形式单一匮乏、井下逃生指引及交通调度指引智能化水平低等问题,提出一种基于矿用LED拼接屏和本安型声光报警器的多媒体信息发布系统设计方案。该信息发布系统可根据客户显示需求,快速编辑显示预案,能提供文字、声音、图形、数据、报表等形式的信息发布,并能联动显示多种监测监控系统的数据,有效提高煤矿的信息发布水平和智能化水平。 展开更多
关键词 矿用LED拼接屏 本安型声光报警器 多媒体信息发布系统 联动显示 信息发布水平
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University Student Sleep Quality: Some Health Insights regarding Light Exposure
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作者 Kathy Sexton-Radek Luciana Luna 《Health》 CAS 2022年第3期368-376,共9页
Young adult sleep quality is reported to be compromised in the literature with shortened sleep intervals, daytime napping, excessive daytime sleepiness and excessive wakeups. The description of young adult sleep quali... Young adult sleep quality is reported to be compromised in the literature with shortened sleep intervals, daytime napping, excessive daytime sleepiness and excessive wakeups. The description of young adult sleep quality commonly includes the rationale that the independent schedule of the young adults coupled with their preferred social schedule, work and academic schedules leaves the planning for sleep to last place. Despite mentation and memory reductions with sleep deprivation secondary to poor sleep quality documented in young adults, the poor sleep quality prevails. This study is focused on the elements of arousal during a young adult’s day that may predispose them to elevated activation and difficulty relaxing sufficiently to fall asleep. It was hypothesized that light exposure was elevated in young adults with poor sleep quality. Light exposure in terms of overhead bright lights in classrooms and laboratories of the academic environment, bright light in terms of video monitors/TVs/tablets/phone exposure is sufficiently stimulating to cause cognitive activation was light exposure. 展开更多
关键词 SLEEP Young Adults ADOLESCENCE Sleep Loss Sleep Quality light levels Physical Activity/Exercise and Sleep
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A Control System Design to Establish Dose-Response Relationships in Wound Healing Therapy
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作者 Jacquelyn Dawn Parente Knut Moller 《Journal of Biomedical Science and Engineering》 2017年第5期76-85,共10页
Advanced biophysical wound healing therapies can apply mechanical, electrical, or light energy to re-stimulate healing processes in chronic wounds. Despite the growing evidence of the clinical efficacy of these therap... Advanced biophysical wound healing therapies can apply mechanical, electrical, or light energy to re-stimulate healing processes in chronic wounds. Despite the growing evidence of the clinical efficacy of these therapies, the optimal treatment stimulation parameters remain unknown and there are no standard treatment protocols. We introduce a closed-loop control design as an experimental system to study the dose-response of wound healing therapy treatment within a prescribed multidimensional and multimodal stimulation parameter space. Systems engineering approaches are applied to the control problem for estimation of a transfer function and model equations derived for use in optimal model-based control. The experimental control system design consisted of simultaneous application of biophysical energies inputted into a wound system. A study design set up including the use of negative pressure wound therapy, electrical stimulation therapy, and photobiomodulation device systems was described. Treatment stimulation parameters were selected from experimental ranges used in the scientific literature. Classical control methods and model-based control were suggested for model selection and evaluation and design of the overall control system. An experimental design for multimodal biophysical wound healing therapy control system is introduced to establish the dose-response interactions for development of therapeutic applications and device design. 展开更多
关键词 Chronic wounds High voltage pulsed current Low level light therapy Negative pressure wound therapy Modeling and control PHOTOBIOMODULATION Wound healing
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一种基于微光夜视系统下光电阴极探测的评价因子
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作者 胡朝龙 刘磊 +3 位作者 钱芸生 莫涌超 拜晓锋 石峰 《应用光学》 CAS 北大核心 2023年第3期628-635,共8页
光谱匹配系数是微光夜视仪性能评估的重要参数,但传统的光谱匹配系数只能反映出光电阴极在响应波长范围内与目标光谱的吻合程度,并不能区分出不同代的光电阴极在微光夜视系统中的性能。因此,结合初始对比度、光电阴极的积分灵敏度和光... 光谱匹配系数是微光夜视仪性能评估的重要参数,但传统的光谱匹配系数只能反映出光电阴极在响应波长范围内与目标光谱的吻合程度,并不能区分出不同代的光电阴极在微光夜视系统中的性能。因此,结合初始对比度、光电阴极的积分灵敏度和光谱转换系数建立了一个评价因子方程,用于描述光电阴极对探测景物的影响,同时对目标与背景的初始对比度公式进行改进,提高了初始对比度的准确性。计算超二代光电阴极材料New S25和三代光电阴极材料GaAs与不同景物的光谱匹配系数和评价因子,New S25与景物的光谱匹配系数要大于GaAs与景物的光谱匹配系数,证明了光谱匹配系数的局限性;GaAs与景物的评价因子大于New S25与景物的评价因子,证明了提出的评价因子能够更有效地评估微光夜视系统的性能。 展开更多
关键词 微光夜视系统 光谱匹配系数 初始对比度 评价因子 积分灵敏度
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一种改进的微光夜视系统视距探测方程
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作者 莫涌超 刘磊 +3 位作者 钱芸生 胡朝龙 拜晓锋 石峰 《应用光学》 CAS 北大核心 2023年第4期887-897,共11页
视距是评估微光夜视成像系统性能的一个重要参数。随着微光夜视探测技术的发展,经典视距模型的视距仿真结果与实测结果出现了一些偏差,特别是在10-3 lx低照度条件下视距仿真结果不甚理想,这对微光夜视仪在实际应用中造成了很大的阻碍。... 视距是评估微光夜视成像系统性能的一个重要参数。随着微光夜视探测技术的发展,经典视距模型的视距仿真结果与实测结果出现了一些偏差,特别是在10-3 lx低照度条件下视距仿真结果不甚理想,这对微光夜视仪在实际应用中造成了很大的阻碍。针对这一问题,从微光成像系统成像链路的三个环节对经典视距模型进行修正:考虑大气透过率对微光夜视系统视距的影响并对经典视距模型中的大气透过率因子进行修正;基于像增强器噪声因子对视距模型进行修正;考虑人眼视觉传递特性对微光夜视系统视距的影响,在系统的传递函数模型中加入了简化的人眼视觉模型。进而推导出改进的视距模型。结合野外试验数据,验证了改进视距模型的有效性和实用性,这对于微光夜视系统的设计、评估和应用具有一定的指导性意义。 展开更多
关键词 微光夜视系统 视距模型 大气透过率 噪声因子 人眼视觉模型
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用于单筒双目微光夜视仪的折叠式光学系统设计
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作者 周继德 窦沂蒙 +3 位作者 孙良伟 杨帆 吕超杰 徐康恺 《光电子技术》 CAS 2023年第3期243-247,共5页
设计了一种折叠式光学系统来缩短微光夜视仪轴向尺寸,提升头戴式微光夜视仪佩戴舒适性。首先给出总体设计,包括折反式物镜和长工作距离、双通道目镜系统设计,之后通过理论计算获得物镜和目镜的指标参数,最后选用符合要求的初始结构,采... 设计了一种折叠式光学系统来缩短微光夜视仪轴向尺寸,提升头戴式微光夜视仪佩戴舒适性。首先给出总体设计,包括折反式物镜和长工作距离、双通道目镜系统设计,之后通过理论计算获得物镜和目镜的指标参数,最后选用符合要求的初始结构,采用软件对折叠式光学系统进行优化设计。采用折叠式光学系统的微光夜视仪,与传统直视型夜视仪相比轴向长度由110 mm减少到70 mm,更接近佩戴者头部,可以有效提升佩戴舒适度。 展开更多
关键词 折叠式微光夜视仪 光学系统设计 非球面 重心
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某围垦区渔光互补项目内涝水位计算
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作者 焦伟杰 顾裕兵 郑勇峰 《电力勘测设计》 2023年第4期77-84,共8页
沿海围垦区处于流域最下游,既是承泄区又是排水区,并受外海潮水顶托影响,洪水情况复杂;确定此类围垦区渔光互补电站的设计水位,常规的水文勘测方法难以适用。以浙江嵊泗县大洋山岛外云鹅围垦区渔光互补项目为例,在分析山坡汇水、场区积... 沿海围垦区处于流域最下游,既是承泄区又是排水区,并受外海潮水顶托影响,洪水情况复杂;确定此类围垦区渔光互补电站的设计水位,常规的水文勘测方法难以适用。以浙江嵊泗县大洋山岛外云鹅围垦区渔光互补项目为例,在分析山坡汇水、场区积水、潮水顶托及挡潮闸、泵站排涝能力的基础上,构建针对内涝水位的流域蓄排计算模型,计算泵站不同排涝能力时场区最大内涝水位,绘制两者的关系曲线及内涝水位、潮位与产流过程变化曲线,为工程区泵站排涝能力的确定与内涝水位的控制提供依据。 展开更多
关键词 沿海围垦区 渔光互补 内涝水位 蓄排计算模型
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微光成像系统三维噪声测量及其分析 被引量:10
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作者 李升才 金伟其 张长泉 《北京理工大学学报》 EI CAS CSCD 北大核心 2005年第5期439-442,共4页
为了分别从时域和空域对微光成像系统的噪声特性进行测量和分析,分别建立了微光成像系统三维噪声模型及其测量系统,并对微光ICCD成像系统和CCD成像系统的三维噪声进行了测量与分析.测量结果表明:随着ICCD像增强器光阴极面照度的提高,空... 为了分别从时域和空域对微光成像系统的噪声特性进行测量和分析,分别建立了微光成像系统三维噪声模型及其测量系统,并对微光ICCD成像系统和CCD成像系统的三维噪声进行了测量与分析.测量结果表明:随着ICCD像增强器光阴极面照度的提高,空间噪声、时间噪声、信号总平均值和信噪比均升高,符合微光ICCD成像系统的实际性能.通过三维噪声分析,实现了区分微光ICCD(或CCD)成像系统中由成像面缺陷和死像素点形成的两种固定图案噪声,且对光锥耦合技术进行定性的评价. 展开更多
关键词 空间噪声 时间噪声 三维噪声 信噪比 微光成像系统
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微光夜视仪分辨力客观评价判据研究 被引量:5
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作者 刘正云 谭谦 +3 位作者 苏建刚 杨舒哉 张洪伟 阚虎 《兵工学报》 EI CAS CSCD 北大核心 2000年第2期149-152,共4页
本文利用灰度 -梯度共生矩阵模型对微光夜视仪分辨力测量图像的纹理特征进行了分析 ,通过对大量图像的纹理特征参数的计算 ,结果表明 ,梯度熵能对微光夜视仪分辨力测量图像的纹理特征作出有效的客观评价 ,其计算结果与人眼的观察结果具... 本文利用灰度 -梯度共生矩阵模型对微光夜视仪分辨力测量图像的纹理特征进行了分析 ,通过对大量图像的纹理特征参数的计算 ,结果表明 ,梯度熵能对微光夜视仪分辨力测量图像的纹理特征作出有效的客观评价 ,其计算结果与人眼的观察结果具有较好的一致性。通过对人眼观察结果与计算结果比较表明 。 展开更多
关键词 微光夜视仪 分辨力 梯度熵 客观评价 判据
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定量中子数字成像散射校正的蒙特卡罗模拟 被引量:2
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作者 魏彪 马晓昕 +2 位作者 金炜 冯鹏 米德伶 《强激光与粒子束》 EI CAS CSCD 北大核心 2008年第9期1545-1550,共6页
中子数字成像过程中,散射中子可降低像质致使提取样品的定量信息变得困难。针对该情况,分析了中子微光成像系统图像散射降质的原理,采用点扩展函数的叠加来表征散射中子引起图像降质的过程,借助于蒙特卡罗方法(MC)对点扩展函数进行模拟... 中子数字成像过程中,散射中子可降低像质致使提取样品的定量信息变得困难。针对该情况,分析了中子微光成像系统图像散射降质的原理,采用点扩展函数的叠加来表征散射中子引起图像降质的过程,借助于蒙特卡罗方法(MC)对点扩展函数进行模拟和建模,将点扩展函数描述为样品厚度以及样品到探测器距离为参量的解析函数,研究了点扩展函数的计算方法。研究结果表明,借助于MC方法构建系统的点扩展函数之解析函数,并利用该函数对中子图像进行散射校正,是一种行之有效的定量中子数字成像散射校正方法。 展开更多
关键词 定量中子数字成像 微光成像系统 散射校正 点扩展函数 蒙特卡罗方法
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微光增强型电荷耦合装置成像系统三维噪声模型及其测量分析 被引量:4
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作者 李升才 徐宗昌 肖顺旺 《兵工学报》 EI CAS CSCD 北大核心 2006年第3期463-466,共4页
为了方便地计算三维噪声,提出了一种新的三维噪声计算方法,该方法对离散型微光成像系统三维噪声测量和质量评价具有十分重要的实用价值。利用微光成像系统三维噪声测量系统,结合数字图像处理技术,测量了微光增强型电荷耦合装置(ICCD)成... 为了方便地计算三维噪声,提出了一种新的三维噪声计算方法,该方法对离散型微光成像系统三维噪声测量和质量评价具有十分重要的实用价值。利用微光成像系统三维噪声测量系统,结合数字图像处理技术,测量了微光增强型电荷耦合装置(ICCD)成像系统在四种照度条件下的三维噪声,并对结果进行了分析。分析结果与微光ICCD成像系统实际性能相吻合。 展开更多
关键词 电子技术 夜视技术 三维噪声 空间噪声 时间噪声 信噪比 微光成像系统
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关于实验“拉伸法测杨氏模量”的思考 被引量:5
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作者 庄建 青莉 《实验科学与技术》 2006年第3期69-71,共3页
通过对实验“拉伸法测杨氏模量”的分析,建议对该实验进行改进,以适应物理实验教学改革的需要。
关键词 杨氏模量 光杠杆 螺旋测微计
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基于最小可分辨对比度的直视微光夜视系统综合性能评价 被引量:3
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作者 王吉晖 金伟其 王霞 《兵工学报》 EI CAS CSCD 北大核心 2010年第2期184-190,共7页
基于最小可分辨对比度(MRC)信道宽度理论,研究了直视微光夜视系统综合性能评价问题。通过对典型夜视仪整机系统综合性能分析表明:MRC信道宽度理论可定量分析人眼视觉与整机系统的匹配状态、评价系统合理性,而且还可有效解释夜视仪整机... 基于最小可分辨对比度(MRC)信道宽度理论,研究了直视微光夜视系统综合性能评价问题。通过对典型夜视仪整机系统综合性能分析表明:MRC信道宽度理论可定量分析人眼视觉与整机系统的匹配状态、评价系统合理性,而且还可有效解释夜视仪整机使用中遇到的一些问题。对理论和实际系统的分析证明了MRC信道宽度理论对于直视型微光夜视系统综合性能评价的有效性及合理性,对微光夜视系统的优化设计具有重要的指导作用。 展开更多
关键词 光电子学与激光技术 微光夜视系统 性能评价 MRC信道宽度 角放大率
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微光电视图像的实时降噪处理系统 被引量:6
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作者 谈新权 黄铁侠 吉书鹏 《华中理工大学学报》 CSCD 北大核心 1992年第4期41-44,共4页
本文提出了一种用于微光电视的实时降噪处理系统.文中简要分析了微光电视的噪声;比较了图像实时去噪的方法;较详细地论述了所提出的方案的原理、设计方法及实验结果.实时处理实验表明,该系统对降低图像的统计型全频带噪声特别有效.
关键词 实时图像处理 图像 噪声 微光电视
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