A search-free near-field source localization method with exact signal model

Most of the near-field source localization methods are developed with the approximated signal model,because the phases of the received near-field signal are highly non-linear.Nevertheless,the approximated signal model based methods suffer from model mismatch and performance degradation while the exact signal model based estimation methods usually involve parameter searching or multiple decomposition procedures.In this paper,a search-free near-field source localization method is proposed with the exact signal model.Firstly,the approximative estimates of the direction of arrival(DOA)and range are obtained by using the approximated signal model based method through parameter separation and polynomial rooting operations.Then,the approximative estimates are corrected with the exact signal model according to the exact expressions of phase difference in near-field observations.The proposed method avoids spectral searching and parameter pairing and has enhanced estimation performance.Numerical simulations are provided to demonstrate the effectiveness of the proposed method.

Hybrid Slip Model for Near-Field Ground Motion Estimation Based on Uncertainty of Source Parameters

The hybrid slip model used to generate a finite fault model for near-field ground motion estimation and seismic hazard assessment was improved to express the uncertainty of the source form of a future earthquake.In this process, source parameters were treated as normal random variables, and the Fortran code of hybrid slip model was modified by adding a random number generator so that the code could generate many finite fault models with different dimensions and slip distributions for a given magnitude.Furth...

Research on the Application of Green Lighting Technology in Sports Lighting

With China’s continued development of society and economy, the importance of ecological environmental protection is growing. This protection has become an indispensable part of social development. The use of various green environmental protection equipment can effectively promote ecological environmental protection and reduce the adverse effects of human activities on the environment. In the field of sports lighting equipment in China, traditional lighting methods constitute an inherent danger to the environment, leading to a waste of valuable resources and environmental pollution. This study involves a multi-tile-multifunctional-function controller, which effectively solves the control problem of the control light. In the sports lighting group, the high and low-level lighting of the sports lighting group, and adjust the light from the height highly effectively to adjust each height. The low-shot mode reduces the power consumption of the system by about 33% to 60%, which significantly helps energy saving. By optimizing the performance of the lighting system, promoting the preservation of power resources, reducing the adverse effects of pollution caused by equipment utilization and energy waste, and promoting the harmonious cohabitation of human and natural environment. .

基于不同数据源的数字孪生小流域底板模型精度检验

为解决小流域综合治理规划设计中基础地形数据获取困难等问题,基于合成孔径雷达卫星遥感影像、倾斜摄影影像、光探测测距影像等3种主流遥感数据源,分别建立栖龙湾小流域数字孪生底板模型,进而提取主沟道纵断面、2块梯田样地边界、10个林地样区的郁闭度,与人工解译和实测结果对比进行精度检验,结果表明:以光探测测距影像为数据源的提取精度最高,以倾斜摄影影像为数据源的提取精度次之,以孔径雷达卫星遥感影像为数据源的提取精度最低。鉴于3种数据源小流域底板模型各有优缺点,可根据实际工作需要进行多源数据融合,以改善数字孪生技术在小流域综合治理规划设计中的应用效果。在栖龙湾小流域内选择石坎梯田地块进行合成孔径雷达卫星遥感影像与倾斜摄影影像数据融合、选择科普展览馆进行倾斜摄影影像与光探测测距影像数据融合,均取得良好的效果。

近红外漫射光在人体组织中的传播及探测器排布研究

为了研究漫反射光谱法在检测内部组织有效信息方面的径向最远探测距离和合适的探测器排布方式,构建了人体皮下组织模型,利用蒙特卡罗(MC)方法对760 nm近红外光在组织中的传输过程进行了模拟。根据不同组织的光学特性,建立了脂肪-肌肉双层MC模型。在模型中,通过调整脂肪和肌肉双层组织的垂直厚度模拟了双层组织的多种情况,分析了不同情况下、不同距离处逃逸光子的分布、数量和剩余权重。结果表明,在该模型下,将探测器排布在距离光源大约3 cm或更近的位置,采集到的光子信号可以有效体现组织内部的信息。基于MC模拟的结果,分析设计了三种可应用于无创血流或血氧检测的探测器排布方式。通过比较发现,多光源-多探测器混合排布设计不仅可以更有效地收集组织的漫射光,提供更均匀的光子分布,而且相较于单光源-多探测器,该设计可以最大限度地利用探测器的数量实现对组织同一深度更大面积的检测。这为设计近红外血流或血氧无创检测光谱仪器提供了思路。

基于激光扫描的室内VLC光源布局设计方法

为了合理设计光源布局,提出基于激光扫描的室内可见光通信(Visible Light Communication,VLC)光源布局设计方法。应用激光扫描技术获取并处理室内信息(激光点云数据)。根据VLC信号传输特征构建链路模型,获取不同链路的脉冲响应函数。计算室内光照度,并分析光照度分布情况。构建适应度函数,通过粒子群算法循环迭代运算,获得室内VLC光源布局设计的最佳方案。实验数据显示:应用提出方法获得的光线追迹侧视图光线覆盖范围较大,均匀照明率数值超过了最小限值0.70lx,证实了提出方法应用后的光源布局更加合理。

Optimization management of hybrid energy source of fuel cell truck based on model predictive control using traffic light information

Energy optimization management can make fuel cell truck(FCT)power system more efficient,so as to improve vehicle fuel economy.When the structure of power source system and the torque distribution strategy are determined,the essence is to find the reasonable distribution of electric power between the fuel cell and other energy sources.The paper simulates the assistance of the intelligent transport system(ITS)and carries out the eco-velocity planning using the traffic signal light.On this basis,in order to further improve the energy efficiency of FCT,a model predictive control(MPC)-based energy source optimization management strategy is innovatively developed,which uses Dijkstra algorithm to achieve the minimization of equivalent hydrogen consumption.Under the scenarios of signalized intersections,based on the planned eco-velocity,the off-line simulation results show that the proposed MPC-based energy source management strategy(ESMS)can reduce hydrogen consumption of fuel cell up to 7%compared with the existing rule-based ESMS.Finally,the Hardware-in-the-Loop(HiL)simulation test is carried out to verify the effectiveness and real-time performance of the proposed MPC-based energy source optimization management strategy for the FCT based on eco-velocity planning with the assistance of traffic light information.

Prediction of near-field strong ground motions for scenario earthquakes on active fault

A method to predict near-field strong ground motions for scenario earthquakes on active faults is proposed. First, macro-source parameters characterizing the entire source area, i.e., global source parameters, including fault length, fault width, rupture area, average slip on the fault plane, etc., are estimated by seismogeology survey, seismicity and seismic scaling laws. Second, slip distributions characterizing heterogeneity or roughness on the fault plane, i.e., local source parameters, are reproduced/evaluated by the hybrid slip model. Finally, the finite fault source model, developed from both the global and local source parameters, is combined with the stochastically synthetic technique of ground motion using the dynamic comer frequency based on seismology. The proposed method is applied to simulate the acceleration time histories on three base-rock stations during the 1994 Northridge earthquake. Comparisons between the predicted and recorded acceleration time histories show that the method is feasible and practicable.

Modeling of Low Coherence Interferometry Using Broadband Multi-Gaussian Light Sources

Using a low coherence interferometry （LCI） model, a comparison of broadband single-Gaussian and multi-Gaussian light sources has been undertaken. For single-Gaussian sources, the axial resolution improves with the source bandwidth, confirming the coherence length relation that the resolution for single Gaussian sources improves with increasing spectral bandwidth. However, narrow bandwidth light sources result in interferograms with overlapping strata peaks and the loss of individual strata information. For multiple-Gaussian sources with the same bandwidth, spectral side lobes increase, reducing A-scan reliability to show accurate layer information without eliminating the side lobes. The simulations show the conditions needed for the resolution of strata information for broadband light sources using both single and multiple Gaussian models. The potential to use the model to study optical coherence tomography （OCT） light sources including super luminescent diodes （SLDs）, as reviewed in this paper, as well as optical delay lines and sample structures could better characterize these LCI and OCT elements. Forecasting misinformation in the interferogram may allow preliminary corrections. With improvement to the LCI-OCT model, more applications are envisaged.

局域热平衡Sn等离子体极紫外辐射不透明度和发射谱的理论研究

锡(Sn)是13.5 nm光刻光源的材料,Sn等离子体辐射性质对光源设计意义重大.基于细致能级模型,在局域热平衡假设条件下计算得到了Sn等离子体辐射不透明度和发射谱.使用多组态Dirac-Fock方法获得了Sn^(6+)-Sn^(14+)离子的能级和辐射跃迁振子强度等基本原子参数.针对波长在13.5 nm附近的4d-4f和4p-4d跃迁系,重点考虑了4d^(m)-4f^(m)(m=1,2,3,4)和4p^(n)-4d^(n)(n=1,2,3)的电子关联效应.在大规模组态相互作用计算中,每种电荷态离子的精细能级数目约为20万.对较强的吸收谱线(振子强度大于0.01),其长度和速度表示的相对差异为20%—30%.基于精密原子参数,计算了Sn等离子体在30 eV,0.01 g/cm^(3)条件下的透射谱,与实验结果基本符合.系统计算了温度16—30 eV,密度0.0001—0.1 g/cm^(3)条件下的Sn等离子体辐射不透明度和发射光谱,分析了极紫外(extreme ultraviolet,EUV)光谱随温度和密度的变化规律.研究表明温度一定时,密度增大会使得13.5 nm附近的辐射不透明度和发射谱包络增宽.而密度一定时,随着温度的增加,辐射不透明度和发射谱在13.5 nm附近存在明显的窄化效应.本文工作有助于EUV光刻光源的设计和研究.

基于双域融合与亮度补偿的室内图像增强算法

针对室内环境下的图像易存在失真、整体偏暗、点光源区域明暗交接处存在光晕效应、边缘细节丢失等问题,提出一种基于双域融合与点光源亮度补偿模型相结合的室内图像增强算法。该算法首先采用Canny算子边缘检测方法对图像进行分割,区分出明亮区域和非明亮区域,然后使用亮通道先验算法和暗通道先验算法粗算明亮区域和非明亮区域的透射率后进行正则化求解,用含有归一化参数的点光源亮度补偿模型进行最优步长迭代优化透射率,使图像透射率具有自适应调节能力。黄玉川煤矿选煤厂中监控图像具有典型的失真、偏暗、点光源影响大等特点,以此应用背景为例,对所提出的算法进行实验验证,结果表明处理后图片在峰值信噪比(PSNR)平均提高约20%、平均梯度(MG)平均提高约25%、信息熵(IE)平均提高约30%、结构相似度(SSIM)平均提高约25%,在减少图像明暗交接处光晕、细节保持、鲁棒性等方面均有显著提升。

视觉检测系统的补光系统设计与优化方法

针对当前视觉检测系统光源照度优化研究未充分考虑实际检测环境存在的遮光、反光等照明干扰问题,以芯片封装质量视觉检测为例,提出一种基于图像信息的视觉检测系统补光系统设计与优化方法。该方法设计补光系统模型,并通过奇异值分解进行简化;根据图像目标区域灰度分布获取对应照度分布;以目标区域最均匀照度分布为优化目标,应用粒子群算法对补光系统各LED亮度权值进行寻优;通过Arduino控制板输出对应PWM脉冲控制LED实现补光系统对目标区域的照明优化。实验结果表明,本方法理论上可将目标区域照度均匀度提升至92%左右,且理论优化照度分布与实际优化照度分布规律基本一致。因此,提出补光光源优化方法目标合理,可用于视觉检测系统具有最优照明效果时的补光光源各LED亮度权值的获取。

光源光斑直径对苹果霉心病近红外检测的影响

为实现中早期霉心病苹果的有效剔除以提高苹果的整体品质,该研究利用近红外光谱技术对苹果霉心病进行快速无损检测,从光谱和分类模型两方面探究光源光斑直径对苹果霉心病检测的影响。在30、50及70 mm光源光斑直径条件下采集了苹果样本的透射光谱,分析不同光源光斑直径下健康苹果和霉心病苹果的光谱差异,然后应用支持向量机(support vector machines,SVM)和粒子群算法优化-最小二乘支持向量机(particle swarm optimization-least squares support vector machine,PSO-LSSVM)方法建立苹果霉心病的分类模型,并对不同光源光斑直径下的分类模型性能进行对比。在此基础上,采用竞争自适应重加权采样(competitive adaptive reweighted sampling,CARS)方法筛选特征波长变量并建立分类模型。结果表明,30 mm光源光斑直径对苹果霉心病的检测效果最好,建立的SVM和PSO-LSSVM分类模型性能均最优。30 mm光源光斑直径下,最优PSO-LSSVM模型的预测集的灵敏度、特异度和正确率分别为89.5%、95.5%和92.7%。CARS-PSO-LSSVM分类模型性能比全波段的分类模型性能略有下降,预测集的灵敏度、特异度和正确率分别为89.5%、90.9%和90.2%,但建模变量数仅占原波长变量数的4.2%,有效地简化了分类模型。该研究为苹果霉心病的快速无损高精度检测提供技术支撑。

空间探测相机光学系统的杂散光分析和优化设计

由于空间光环境的复杂性,抑制杂散光对保证空间相机成像性能尤其重要,该文针对宽光谱波段成像的空间探测相机光学系统进行杂散光分析和抑制优化设计。通过SOLIDWORKS和TracePro的无损式数据交互建立光机模型,并从光机材料的表面特性、机械结构、镜片透过率等多角度优化杂散光模型,再利用朗伯体光源分别对正反向进行光线追迹,然后结合光机模型的半剖图对系统关键表面进行重点取样分析。分析结果表明:优化后的光机系统在离轴角10.3°~15.4°内,点源透过率值与优化前的系统相比下降了66%~99.4%,在离轴角大于14.2°时点源透过率值接近10^(−4)量级,在离轴角18.4°处杂散光的点源透过率约为10^(−4)量级。最后通过鬼像实验,进一步证明了优化后的光机系统设计方法具有良好的杂散光抑制效果。

3种光源下的朗伯体表面反射模型

为了理想化物体表面反射模型,通过辐射度学和球面三角公式推导出条形光源、均匀光源和半球均匀光源照射下的朗伯体场景辐射亮度,进而得到了3种光源下的朗伯体表面反射模型.

基于蒙特卡罗的脑血氧检测光源——探测器最优距离研究

为提高近红外光谱技术的脑血氧检测装置测量精度,需要选择最优的光源—探测器(SD)距离。传统的脑血氧检测装置,其传感器探头部分的SD距离是固定的,且在选择SD距离时没有经过研究,多根据经验进行选择,因而会造成实际使用中测量结果的不准确。根据光在头部组织中的传输特性,选定一组颅脑组织的特性参数,利用蒙特卡罗方法对5层颅脑组织模型进行仿真,研究光在头部组织中的传输特性,根据光子传输路径分析光子在组织中传输的最大可达深度和散射传输距离。通过分析有效深度比(EDR)和灰质层信息比(GMLIR),选择出适合此组选定颅脑参数的一组最优距离SD=1cm和SD=3.5cm。与传统检测装置相比,通过优化光源—探测器之间的距离,为脑血氧检测装置的传感器设计及装置测量精度优化提供了一个新思路。

基于改进分布估计的算法在井下监控系统中的应用研究

视频监控系统在煤矿井下综采工作中应用广泛,而视频监控采集图像质量的高低直接决定工作人员安全和生产工作效率。目前,受井下粉尘、水汽和光源分布不均等因素的影响,采集的图像信息存在雾气较大、图像过曝光和对比度低的问题。传统的暗通道先验去雾算法具有计算速度快、修复效果好的优点,广泛应用于井下去雾,但在处理煤矿井下尘雾大、光源分布不均的图像时会导致图像信息大量丢失和光源区域纹理受损等问题。针对这些问题,提出了一种改进透射率分布估计的井下去雾算法。通过利用暗态点光源模型,结合暗通道可信度权值因子和最优暗通道去雾图像,对透射率分布进行改进,对井下有雾图像进行去雾处理。试验结果表明,改进的透射率分布估计去雾算法相较于Retinex算法,峰值信噪比、信息熵、标准差和平均梯度分别提高了16.25%、31.39%、17.17%、48.47%,相较于传统暗通道先验去雾算法分别提高了47.24%、35.24%、21.64%、51.79%。实验数据表明改进的透射率分布估计去雾算法处理后的井下图像纹理细节损失小,对比度和清晰度都得到了有效提升。

三维光学模型的激光图像边缘检测研究

常规方法对激光图像进行边缘检测时,边缘检测会发生模糊,影响激光图像中心点的定位精度,为此设计基于三维光学模型的激光图像边缘检测方法。通过三维光学模型获取激光图像内部参数,分析激光粒子跃迁的能量变化过程,将图像分解过程用维矩阵模型进行表示,使用Gabor滤波器对激光图像进行滤波预处理,利用卷积神经网络完成采样运算,对比结果判定像素点是否为边缘点,完成检测。测试结果表明:本方法图像检测边缘检测得到的图像中心点定位横纵距离偏差都在0.1 mm以下,检测精度高于90%,检测时间低于1.25 s,验证了方法的有效性。

LED-based spectrally tunable light source with optimized f itting

According to the LED spectra measured in the rated current, Gauss distribution function and asymmetric Gaussian distribution function methods are used to simulate the individual LED spectrum. Based on this mathematical model, 32 LEDs are used to synthesize arbitrary spectral distribution of the light source. Processing the spectral data with multiple linear regressions, CIE illuminant A and CIE illuminant D65 are simulated. The results show that for each LED, different Gauss models should be used. The simulation results are quite satisfying. However, there is a difference between the simulation results and the experimental results. The spectral evaluation indices of fitted both CIE illuminant A and CIE illuminant D65 do not exceed 2.5%. But in experiment, because of the changes of the peak wavelength and the FWHM caused by the current, the spectral evaluation indices of fitted CIE illuminant A and CIE illuminant D65 are around 5%.

紧凑型LED配光设计中光源模型可靠性研究

针对现有LED光源建模适用条件及可靠性不确定性的问题,对紧凑型LED配光设计中光源建模可靠性进行了研究.通过优化设计具有不同透镜光源直径比模型的方法,对点光源、表面光源、ray文件光源三种建模方式在系统中的差异进行分析对比.整体设计以ray文件光源模型为基准,以常规紧凑型全反射式透镜为二次配光元件,对不同透镜光源直径比(光束角分别为±15°、±10°、±5°)的光学系统进行优化设计和分析计算.结果表明:在能量利用率误差为±2%的范围内,光束角为±15°,透镜光源直径比大于36∶2时,表面光源建模可代替ray文件光源建模;光束角±10°,透镜光源直径比为44∶2时,表面光源建模可代替ray光源建模;光束角为±5°,透镜光源直径比为82∶2时,表面光源建模可代替ray文件光源建模.但是在±2%误差范围内,点光源无论在何种透镜光源直径比,任何光束角下均不能代替ray文件光源.这一结果为紧凑型系统设计中光源模拟提供了依据,同时解决了采用ray文件光源建模进行辅助优化设计耗时较长的问题,为相关研究提供了参照依据.