Estimation-free spatial-domain image reconstruction of structured illumination microscopy

Structured illumination microscopy(SIM)achieves super-resolution(SR)by modulating the high-frequency information of the sample into the passband of the optical system and subsequent image reconstruction.The traditional Wiener-filtering-based reconstruction algorithm operates in the Fourier domain,it requires prior knowledge of the sinusoidal illumination patterns which makes the time-consuming procedure of parameter estimation to raw datasets necessary,besides,the parameter estimation is sensitive to noise or aberration-induced pattern distortion which leads to reconstruction artifacts.Here,we propose a spatial-domain image reconstruction method that does not require parameter estimation but calculates patterns from raw datasets,and a reconstructed image can be obtained just by calculating the spatial covariance of differential calculated patterns and differential filtered datasets(the notch filtering operation is performed to the raw datasets for attenuating and compensating the optical transfer function(OTF)).Experiments on reconstructing raw datasets including nonbiological,biological,and simulated samples demonstrate that our method has SR capability,high reconstruction speed,and high robustness to aberration and noise.

Efficacy and safety of Usights UC100 illuminated microcatheter in microcatheter-assisted trabeculotomy

AIM:To evaluate the efficacy and safety of Usights UC100 illuminated microcatheter in microcatheter-assisted trabeculotomy(MAT).METHODS:Totally 10 eyes of 10 patients with primary open angle glaucoma(POAG)who underwent MAT facilitated by Usights UC100(5 eyes)or iTrack(5 eyes)were reviewed.The success of this surgery was defined as intraocular pressure(IOP)<22 mm Hg with>30%reduction,without oral glaucoma medications,or additional glaucoma surgery.RESULTS:The mean pre-operative IOP was 25.38±10.22 mm Hg in the Usights UC100 group and 19.98±3.87 mm Hg in the iTrack group.MAT was achieved in all eyes in both groups.The success rates for the Usights UC100 group and iTrack groups were in all and 4 eyes,respectively.Both microcatheters produced a statistically significant reduction in IOP,and eyes using Usights UC100 achieved a lower IOP than the iTrack group at 3mo followup(12.58±1.52 and 14.84±1.89 mm Hg,respectively),but no statistical significance was there.No severe side effects were observed in either group.CONCLUSION:MAT using Usights UC100 or iTrack both achieve significant pressure reduction in cases of POAG,and Usights UC100 is as safe as iTrack.

Construction of enhanced multi-polarization and high performance electromagnetic wave absorption by self-growing ZnFe_(2)O_(4)on Cu_(9)S_(5)

The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrothermal method.The crystallographic and surface phase chemical information,morphological structure,and magnetic and EM parameters of the composites were analyzed.The prepared Cu_(9)S_(5)/ZnFe_(2)O_(4)composites have multiple loss paths for EM waves and present an overall 3D flower-like structure.The Cu_(9)S_(5)/ZnFe_(2)O_(4)composites exhibit a minimum reflection loss of-54.38 dB and a broad effective absorption bandwidth of 5.92 GHz.Through magnetization,ZnFe_(2)O_(4)particles are self-assembled and grown on the surfaces of Cu_(9)S_(5).Such a modification is conducive to the generation of additional cross-linking contact sites and the effective introduction of a large number of phase interfaces,crystalline defects,special three-dimensional flower-like structures,and magneto-electrical coupling loss effects.Moreover,the synergistic effect of multiple loss strategies effectively improves EM wave absorption by the material.This work can provide a strategy for the use of magnetizationmodified sulfide composite functional materials in EM wave absorption.

Research on novel multi-layer and multi-polarized slot-coupling planar antenna array

A novel multi-layer planar antenna array to achieve multi-polarized radiation is developed. U-shaped coupling slots are embedded in the ground plane to extend the bandwidth. The phase relation between adjacent elements in the radiation field is analyzed when adjacent elements are fed in opposite phase. Return loss and radiation pattern are measured for a 16-element antenna array at 12.5 GHz. The radiation pattern shows a good agreement with the calculated one in the shape of the main beam. The return-loss of the proposed antenna array is less than -20 dB in the 12.5 GHz frequency band （12.25-12.75 GHz）. Because of two feed ports the antenna can transmit arbitrary elliptic polarized waves if the two feed ports have different amplitude and phase. The main factors such as element spacing, substrate medium and manufacturing imperfection are analyzed and the corresponding conclusions are presented.

Speckle structured illumination endoscopy with enhanced resolution at wide field of view and depth of field

Structured illumination microscopy(SIM)is one of the most widely applied wide field super resolution imaging techniques with high temporal resolution and low phototoxicity.The spatial resolution of SIM is typically limited to two times of the diffraction limit and the depth of field is small.In this work,we propose and experimentally demonstrate a low cost,easy to implement,novel technique called speckle structured illumination endoscopy(SSIE)to enhance the resolution of a wide field endoscope with large depth of field.Here,speckle patterns are used to excite objects on the sample which is then followed by a blind-SIM algorithm for super resolution image reconstruction.Our approach is insensitive to the 3D morphology of the specimen,or the deformation of illuminations used.It greatly simplifies the experimental setup as there are no calibration protocols and no stringent control of illumination patterns nor focusing optics.We demonstrate that the SSIE can enhance the resolution 2–4.5 times that of a standard white light endoscopic(WLE)system.The SSIE presents a unique route to super resolution in endoscopic imaging at wide field of view and depth of field,which might be beneficial to the practice of clinical endoscopy.

Comparison of point detection and area detection for point-scanning structured illumination microscopy

Structured illumination microscopy(SIM)is suitable for biological samples because of its relatively low-peak illumination intensity requirement and high imaging speed.The system resolution is affected by two typical detection modes:Point detection and area detection.However,a systematic analysis of the imaging performance of the different detection modes of the system has rarely been conducted.In this study,we compared laser point scanning point detection(PS-PD)and point scanning area detection(PS-AD)imaging in nonconfocal microscopy through theoretical analysis and simulated imaging.The results revealed that the imaging resolutions of PSPD and PS-AD depend on excitation and emission point spread functions(PSFs),respectively.Especially,we combined the second harmonic generation(SHG)of point detection(P-SHG)and area detection(A-SHG)with SIM to realize a nonlinear SIM-imaging technique that improves the imaging resolution.Moreover,we analytically and experimentally compared the nonlinear SIM performance of P-SHG with that of A-SHG.

Complex-amplitude Fourier single-pixel imaging via coherent structured illumination

We propose a method of complex-amplitude Fourier single-pixel imaging(CFSI)with coherent structured illumination to acquire both the amplitude and phase of an object.In the proposed method,an object is illustrated by a series of coherent structured light fields,which are generated by a phase-only spatial light modulator,the complex Fourier spectrum of the object can be acquired sequentially by a single-pixel photodetector.Then the desired complex-amplitude image can be retrieved directly by applying an inverse Fourier transform.We experimentally implemented this CFSI with several different types of objects.The experimental results show that the proposed method provides a promising complex-amplitude imaging approach with high quality and a stable configuration.Thus,it might find broad applications in optical metrology and biomedical science.

Compact and robust dual-color linearly polarized illumination source for three-photon fluorescence imaging

The miniaturized femtosecond laser in near infrared-Ⅱregion is the core equipment of threephoton microscopy.In this paper,we design a compact and robust illumination source that emits dual-color linearly polarized light for three-photon microscopy.Based on an all-polarizationmaintaining passive mode-locked fiber laser,we shift the center wavelength of the pulses to the 1.7m band utilizing cascade Raman effect,thereby generate dual-wavelength pulses.To enhance clarity,the two wavelengths are separated through the graded-index multimode fiber.Then we obtain the dual-pulse sequences with 1639.4 nm and 1683.7 nm wavelengths,920 fs pulse duration,and 23.75 MHz pulse repetition rate.The average power of the signal is 53.64mW,corresponding to a single pulse energy of 2.25 nJ.This illumination source can be further amplified and compressed for three-photon fluorescence imaging,especially dual-color three-photon fluorescence imaging,making it an ideal option for biomedical applications.

Radial Basis Approximations Based BEMD for Enhancement of Non-Uniform Illumination Images

An image can be degraded due to many environmental factors like foggy or hazy weather,low light conditions,extra light conditions etc.Image captured under the poor light conditions is generally known as non-uniform illumination image.Non-uniform illumination hides some important information present in an image during the image capture Also,it degrades the visual quality of image which generates the need for enhancement of such images.Various techniques have been present in literature for the enhancement of such type of images.In this paper,a novel architecture has been proposed for enhancement of poor illumination images which uses radial basis approximations based BEMD(Bi-dimensional Empirical Mode Decomposition).The enhancement algorithm is applied on intensity and saturation components of image.Firstly,intensity component has been decomposed into various bi-dimensional intrinsic mode function and residue by using sifting algorithm.Secondly,some linear transformations techniques have been applied on various bidimensional intrinsic modes obtained and residue and further on joining the transformed modes with residue,enhanced intensity component is obtained.Saturation part of an image is then enhanced in accordance to the enhanced intensity component.Final enhanced image can be obtained by joining the hue,enhanced intensity and enhanced saturation parts of the given image.The proposed algorithm will not only give the visual pleasant image but maintains the naturalness of image also.

我国24家检验检测机构洁净环境照度检测能力验证

目的评价我国检验检测机构对洁净环境照度的检测能力。方法回顾性分析中国食品药品检定研究院于2022年在全国范围内首次设计并组织实施的洁净环境照度能力验证项目。基于洁净环境检测的行业特点,该项目分为笔试和实际操作(简称实操)两部分。笔试部分,共3题(限时40 min完成),考察参加测试(简称参测)实验室对检测标准正确理解和掌握的程度,根据专家商议确定的评分标准评分(满分50分)。实操部分,以该院药用辅料和包装材料检定所的2台洁净工作台为现场考核样品,以参测实验室的现场测试结果考察参测实验室的仪器操作和实验水平(限时5 min完成),以Z值进行评价(︱Z︱≤2,>2~<3,≥3分别为满意、有问题、不满意)并打分(满分50分)。以笔试和实操评分之和评价参测实验室的检测能力(≥60分为合格)。结果共24家实验室参加了能力验证并按要求提交了结果报告。笔试,评分为45~50分,满分21家(87.50%)。实操,样品A,满意21家(87.50%),有问题3家(12.50%);样品B,满意23家(95.83%),有问题1家(4.17%),2个样品均无不满意的实验室。24家实验室总评分均合格。结论该次能力验证结果显示,各实验室的检测能力维持良好,但部分实验室存在对标准的理解和掌握仍有欠缺或未按校准周期对照度计进行计量等问题,建议检测人员加深对洁净环境检测标准的理解,相应机构重视仪器的校准,持续提高检测能力。

基于LMIENet图像增强的矿井下低光环境目标检测方法

煤矿井下工作环境复杂,存在人造光源亮度低、粉尘多和水气密度大等不利因素,导致现有的目标检测算法在应用到煤矿井下时,存在提取特征困难、目标识别和定位精度低等问题。提出一种煤矿井下低照度环境目标检测算法,由矿井低光图像增强模块LMIENet和目标检测模块组成,使用图像增强模块对原始图像进行画质提升,恢复各类图像信息,再使用目标检测网络对增强图像进行特定目标检测,有效提高检测的精确度。在图像增强模块中,改进Zero-DCE算法设计轻量级增强参数预测网络,计算像素级增强参数矩阵,用于低光照图像的亮度调整和画质增强,该网络通过设计的非参考损失函数隐性衡量图像的增强效果,引导网络进行无监督学习,使网络能够不依赖配对数据集对原始图像进行自适应的画质增强。目标检测模块中,采用YOLO v8n目标检测模型,其轻量化的模型尺寸和高灵活性可避免模型整体复杂度过高;采用Focal-EIoU Loss改进回归损失函数,有效加速模型收敛并提升模型检测精度。实验结果显示:与经典目标检测算法Faster R–CNN,SSD,RetinaNet,FCOS等相比,提出算法在自建矿井人员数据集上表现出色,低光照环境下目标检测的mAP@0.5达到98.0%,mAP@0.5∶0.95达64.8%,在实验环境中单帧图像推理时间仅11 ms,优于其他对比方法,证明提出算法能够有效实现在煤矿井下低照度复杂环境下的目标检测,且耗时短、计算效率高。

基于超视距的外辐射源信号提取在被动探测中的应用分析

目前外辐射源雷达主要以接收辐射源的直达波信号为主,该方式提取的直达波信号信噪比高,利于后续目标信号检测和处理,但需要收发站通视,对直达波天线架高有要求,这极大地限制了该体制的应用。基于此,文中提出在沿海低海拔条件下,利用超视距侦察截获辐射源信号成为非合作探测的基准信号的思路,分析了其探测机理,和理论误差模型,并结合工程实际,提出了可实现的工程样机,分析了性能指标,给出了仿真结果。结果表明该思路可以应用在后续的工程实践上。

长三角地区集中式露地农业光伏方阵夏季光热环境试验研究

基于太阳照度和环境温度逐时变化,以长三角地区的集中式露地农业光伏方阵为研究对象,在跨度为6.8 m的单跨方阵中沿从南到北的跨度方向取0.65、3.40、6.15 m处的3个和长度方向共面的测试断面,即南区、中区、北区。基于此,进行夏季方阵内外的光热环境测试,分析并明确光伏组件下方区域的光热环境变化规律,为其太阳能资源合理利用、结构改进和夏季农业生产管理提供参考。结果表明,该地区光伏方阵夏季内部3个区域光热环境呈现规律性差异,整体表现为北区略优于南区,中区优于南、北两区。综合考虑作物生长的光热环境需求,一方面可通过结构改进、种植方式优化等方式改善或利用好内部光环境;另一方面基于热环境规律,分类做好内部3个区的夏季灌溉等田间管理,从而推动光伏农业发展升级。

基于深度学习的低光环境车道线检测算法仿真

车道线检测研究是保证车辆自动驾驶安全的基础,但当下研究中存在低光环境车道线检测稳定性差,准确率低的问题,为此提出一种基于改进BFA-Retinex光照补偿深度学习算法,提高图像重点区域的光照水平,通过提取并融合车道线纹理与直方图特征,构建出BRI-SVM低光车道线检测识别模型。模型包括图像补光模块、特征融合模块与车道线检测模块三个模块。BRI-SVM模型首先对Lll低光车道数据集进行灰度化与标准化处理,然后采用改进双边滤波算法提高图像光照基准;接着提取优化图像中的H与G特征,并将二者有机融合;最后基于数据驱动的方法,以深度学习与SVM算法为核心,构建出BRI-SVM模型,并采用交叉验证的方式提升模型性能。多类融合算法模型的仿真结果表明,在Lll低光数据集上,与其它模型相比,BRI-SVM模型的稳定性能与综合性能最高,特征值分别达到96.1%与96.3%,较传统算法分别平均提升了24.4%和23.8%;此外,所构建的模型具有较好的检测时效性与检测准确性,在所有模型评价中排名第2。综上所述,基于改进BFA-Retinex算法的低光照环境下车道线检测模型在具有最高鲁棒性与稳定性的同时,大幅度提高了车道线检测的准确性与时效性。

利用自适应光照初始化的弱光图像增强方法

由于光照分量分解估计的高度不确定性,如何准确估计图像的光照分量一直是基于Retinex模型的图像增强方法需要解决的难题。该文提出一个简单有效的方法,准确估计图像的初始光照分量,进而实现弱光图像增强。具体地,首先根据输入图像得到其对应的光照权重矩阵,以指导光照分量的自适应初始化估计;随后在光照结构约束下,对初始光照分量优化估计,并进一步执行非线性光照调整;最终结合Retinex模型得到增强结果。实验表明,该方法不仅能够实现准确的图像分解估计,而且与现有的弱光图像增强方法相比,该文所提方法在多个数据集上的主观视觉效果和客观评价指标都有更好的表现,同时也保持着良好的运行效率。

一种基于暗亮通道分割融合的低照度环境图像去尘雾及增强方法

受煤矿井下粉尘、水雾和低照度环境影响,对皮带运输系统的监测图像精准识别极为困难。针对现有去尘雾方法的图像处理结果和效率欠佳的问题,提出一种基于暗亮通道分割融合的低照度环境图像去尘雾及增强方法。首先利用阈值分割结合伽马变换修正通道差,解决因低照度环境影响导致的尘雾浓度较大区域与其他区域间像素值差异不明显的问题,修正后通过引导尘雾图像做引导滤波得到更加符合实际情况的全局大气光强;然后为解决暗通道先验在尘雾浓度较大区域失效问题,引入亮通道先验进行补充,使用通道分量来辅助暗通道及亮通道透射率融合,避免因多次分割而导致的边缘像素归属问题;最后将去雾后RGB图像转至HSV空间,对亮度分量进行直方图均衡化并将均衡化前后的亮度分量进行加权融合,采用客观指标评价,选择最优聚合权值进行聚合,同时考虑去雾过程中饱和度损失和亮度分量与饱和度分量间的相关性提出饱和度自适应矫正函数,对图像饱和度进行矫正,色调分量保持不变,随后将图像转回至RGB空间,得到亮度适中、信息保留丰富和色彩鲜艳的图像;为验证所提方法的有效性,采用主观视觉、客观指标和目标检测精度及置信度进行算法对比,实验结果表明所提方法在上述4个指标上均优于被对比算法,其图像细节保留丰富,图像视觉观感更佳。

照明系统中配光元件反射-吸收损耗的计算

在照明光学设计中,光通量利用率是配光元件的一个重要评价指标。基于菲涅尔公式,建立了配光元件反射-吸收损耗的理论模型,并探讨了其适用范围。利用该模型分别计算了自由曲面平凸透镜和全内反射透镜的反射-吸收损耗,并与软件仿真和实验实测的光通量损耗数值进行了对比。研究发现,该理论模型的计算数值与光学软件的仿真结果高度相符,点光源60°平凸准直配光透镜和全内反射透镜的透射率绝对误差分别为0.7%和0.14%,考虑装配误差影响之后,此数值与实验测量结果也基本匹配。利用本研究所建的反射-吸收损耗模型,在照明光学设计中,无需进行软件仿真和实验测试,即能快速而精确地预测出各类配光元件在各个光学表面上的反射损耗和材料吸收损耗,为配光元件的性能评价、结构选择和优化定型提供参考依据。

机坪泛光照明环境仿真与组合机位照明分析

机坪泛光照明系统(AFS,apron floodlight system)是建设绿色机场和节约能耗的重要环节,但对机坪泛光照明环境精细化分析的不足限制了照明节能的策略优化。对此,本文采用DIALux evo平台建立组合机位照度仿真模型,提出基于机坪运行功能的分区照明评价指标,对前列式与转角式组合机位开展参数影响分析。结果表明:对C类停机位需通过双侧高杆灯照明以满足基本照度条件,飞机和廊桥对光线的遮蔽影响不容忽视;转角式组合机位由于照明范围大需控制灯具垂直俯仰角投射方向,当垂直俯仰角大于45°时容易导致眩光指标超出限值,对保障驾驶舱安全性和客舱舒适度较为不利。通过与神经网络算法融合,可进一步完善高杆灯照明参数优化过程。

采煤机截割部低照度图像的边缘检测技术

针对井下低照度环境下采煤机截割部边缘检测任务中存在的边缘缺失、细节模糊等问题,提出一种基于分数阶微分的边缘检测Lif算法。首先采用更大的检测模板尺寸,根据Grünwald-Let-nikov分数阶定义构造最初的分数阶掩膜算子;然后根据Pascal三角形理论确定掩膜算子上各位置的权重系数,并将掩膜算子扩展到4个不同方向;最后将得到的掩膜算子与图像进行卷积,利用图像的局部特征信息对每个方向的微分结果进行后处理。结果表明:(1)在进行多个不同场景的井下低照度图像上的实验时,Lif算法可以更全面地获取图像中不同方向上的边缘信息,在处理低照度图像时具备更强的抗噪性能,并且提取的边缘线条比其余边缘检测算法更加清晰、完整,保留了更多的纹理细节信息。(2)在客观指标评价的对比上,与基于分数阶灰色系统模型的边缘检测算法以及改进的分数阶Sobel边缘检测算法相比,Lif算法在Entropy指标上分别提高了43%、11%,AG指标上分别提高了23%、23%,SSIM指标上分别提高了152%、6%。表明Lif算法在进行采煤机截割部的边缘检测任务时更具优势,研究对井下设备工作运行时的安全性和可靠性提升具有重要意义。

基于红外可见光融合的复杂环境下人脸识别方法

随着深度学习方法的发展,理想环境下基于可见光的人脸识别精度和速度已经达到优秀的水平。但是在弱光等复杂环境下,由于缺少光源,可见光图像无法体现人脸细节,导致人脸识别效果下降甚至失效。为了解决这一问题,提出一种基于红外可见光融合的复杂环境下人脸识别方法。首先,针对低照度环境提出联合CNN(Convolutional Neural Network)和Transformer的红外与可见光融合识别网络,并联CNN和视觉Transformer组成单模态特征融合模块,充分利用源图像的局部细节信息和全局上下文信息。同时,提出一种基于模态平均差异度的多模态特征融合策略,强化对源图像不同区域特征的差异化表达。其次,针对实际应用中融合识别网络模型大、速度慢的问题提出轻量化人脸识别网络Mobile Face Net-Coo和基于边云协同的自适应识别策略,通过图像质量选择识别模型,有效利用硬件资源。实验结果表明,弱光条件下,融合红外光与仅使用可见光图像相比,识别率提升了13.96个百分点。同时,将本方法应用实际项目中,结果表明:本方法在复杂环境下,能提高人脸识别的实时性和准确率。