Machine Vision Based Measurement of Dynamic Contact Angles in Microchannel Flows

When characterizing flows in miniaturized channels, the determination of the dynamic contact angle is important. By measuring the dynamic contact angle, the flow properties of the flowing liquid and the effect of material properties on the flow can be characterized. A machine vision based system to measure the contact angle of front or rear menisci of a moving liquid plug is described in this article. In this research, transparent flow channels fabricated on thermoplastic polymer and sealed with an adhesive tape are used. The transparency of the channels enables image based monitoring and measurement of flow variables, including the dynamic contact angle. It is shown that the dynamic angle can be measured from a liquid flow in a channel using the image based measurement system. An image processing algorithm has been developed in a MATLAB environment. Images are taken using a CCD camera and the channels are illuminated using a custom made ring light. Two fitting methods, a circle and two parabolas, are experimented and the results are compared in the measurement of the dynamic contact angles.

Automated Angle Detection for Industrial Production Lines Using Combined Image Processing Techniques

Angle detection is a crucial aspect of industrial automation,ensuring precise alignment and orientation ofcomponents in manufacturing processes.Despite the widespread application of computer vision in industrialsettings,angle detection remains an underexplored domain,with limited integration into production lines.Thispaper addresses the need for automated angle detection in industrial environments by presenting a methodologythat eliminates training time and higher computation cost on Graphics Processing Unit(GPU)from machinelearning in computer vision(e.g.,Convolutional Neural Networks(CNN)).Our approach leverages advanced imageprocessing techniques and a strategic combination of algorithms,including contour selection,circle regression,polar warp transformation,and outlier detection,to provide an adaptive solution for angle detection.By configuringthe algorithm with a diverse dataset and evaluating its performance across various objects,we demonstrate itsefficacy in achieving reliable results,with an average error of only 0.5 degrees.Notably,this error margin is 3.274times lower than the acceptable threshold.Our study highlights the importance of accurate angle detection inindustrial settings and showcases the reliability of our algorithm in accurately determining angles,thus contributingto improved manufacturing processes.

The Objective Measure of Color Vision in Primary Open Angle Glaucoma

Purpose: To objectively evaluate the clinical application of color pattern reversal visual e-voked potential (CPR-VEP) on primary open angle glaucoma (POAG). Methods: CPR-VEP and FM 100-hue test were performed in 31 eyes with POAG and 33 normal eyes. Color pattern stimulation was presented by color monitor controlled by computer program. The reversal rate of the stimulating pattern was 2 Hz and the spatial frequency of the stimulating was 0.53 cycle/degree. The color stimulating pattern include White /Black , Red/Black , Green/Black , Blue/Black , Yellow /Black , Red/Green and Blue /Yellow . Results : CPR-VEP P1 latencies were obviously prolonged in POAG group in comparison with normal control group in equiluminance. All CPR-VEP P1 amplitudes, except Blue/Black P1 amplitude, show no differences between POAG group and normal control group . Conclusion: P1 latencies of all CPR-VEP and P1 amplitude of Blue/Black CPR-VEP were parameters for identifing acquired dyschromatopsia caused by POAG. The results

Design of Omni-Directional Tilt Sensor Based on Machine Vision

This paper presents a new Omni-Directional Tilt Sensor (ODTS), which consists of the LED light, transparent cone-shaped closed container, mercury, camera, embedded systems and so on. The volume of the mercury in the container is equal to half of the container’s. When the detected surface is horizontal, the shape of mercury in the image captured by the camera is a black disc since the mercury is lightproof. When the detected surface tilts, the mercury flows and the mercury surface always maintains horizontally due to the gravity force of the earth. At this time, some area of the transparent cone-shaped closed container is not shaded by mercury and the border of the mercury’s shape in the captured image is a half circle and a half ellipse. Thus there is a translucent crescent-shaped area in the image. With analyzing this area by the specific algorithm based on machine vision, the tilt angle and directional angle can be obtained. The experimental results show that the ODTS proposed has some advantages, such as simple maintenance, high precision, wide range, low cost, real-time, reliability and high visualization.

基于深度学习的机理模型与数据混合驱动的视觉转角测量方法

为克服基于视觉的转角测量方法容易受到系统干扰的局限性,提出了一种基于深度学习的机理模型和数据混合驱动的视觉转角测量方法。从数学原理上验证了采用等腰三角形作为轴上花纹的合理性和有效性,构建三角花纹转角计算机理数学模型。引入基于YOLOv8的深度学习模型,采用线性组合将两者结合构建成混合转角测量模型。实验结果显示,这种混合模型在测量准度上有显著提升,相比仅用机理模型,其平均误差降低1.125°,均方根误差降低10.05°,在不同环境测试集上仍保持高效性能。该模型充分利用了深度学习模型对图像随机干扰的学习能力,同时保持了数学模型的约束和稳定性,提高了视觉角度测量的准确性,而且增强了其对环境变化以及系统干扰的适应性。

基于图像比对的螺纹牙形补偿量算法研究

为研究牙形失真对螺纹参数测量精度的影响,在分析现有螺纹牙形失真量计算方法的基础上,提出了一种基于机器视觉螺纹牙型角和中径的补偿量算法。将螺纹参数一致的没有螺旋升角的螺纹环槽与有螺旋升角的螺纹塞规图片进行比对,获取螺纹牙型角补偿量,再利用几何关系计算出相应螺纹牙的中径补偿量。经过研究发现,螺纹大径处螺旋升角相同的一系列螺纹产生的牙侧角误差基本一致,且随着螺旋升角的增大,牙侧角误差也随之增大。以螺纹塞规为对象进行对比实验,数据表明采用所提方法获得补偿后的牙型角平均值为59.999°和补偿后的中径平均值为18.290 mm与接触式螺纹综合测量仪所测牙型角平均值60.015°和中径平均值18.326 mm接近,且补偿后的牙型角方差7.76×10^(-5)与中径方差8.65×10^(-4)均小于综合测量仪所测牙型角方差3.38×10^(-3)和中径方差8.55×10^(-3)。结果表明,所提出的补偿算法可行。

Rehabilitation of vision disorder and improved quality of life in patients with primary open angle glaucoma

Background Primary open angle glaucoma （POAG） is a common cause of irreversible blindness. The variable etiology of POAG poses significant challenges for treatment and rehabilitation. We analyzed a large POAG patient cohort during treatment to reveal possible causes of vision disorder, assess vision-related quality of life （VRQL）, and to evaluate the efficacy of rehabilitative treatments. Methods We analyzed the visional disturbances in 500 POAG patients （890 eyes） by regular ophthalmic examination and visual field examination using Humphrey 30-o perimetry. Appropriate rehabilitative treatments for POAG were prescribed based on results of clinical examination and included correction of ametropia, health education, counseling, and the fitting of typoscopes. VRQL was assessed before and after treatment by a VRQL self-assessment questionnaire. Results Scores on the VRQL self-assessment were significantly lower compared to healthy controls. The primary cause of the vision disturbances was ametropia （97.99%）, and 51.61% of the ametropia eyes had not received appropriate correction. The secondary causes of visual impairment were glaucomatous neurodegeneration （26.29%）, complicated cataract, or other accompanying eye diseases. The causes of the clinical low vision （44 patients） were glaucomatous neurodegeneration （32 eyes）, fundus diseases （23 eyes）, keratopathy （11 eyes）, and other eye diseases （10 eyes）. The VRQL scores of patients improved significantly after rehabilitation and the correction of ametropia （P 〈0.01）. Twenty-five patients with low vision were provided with typoscopes, and 21 （84%） experienced significant functional recovery, while the remaining low vision patients could see letter lines two or more levels lower （smaller） on visual charts in a near vision test. Conclusions Vision disorders in POAG patients are common and severe. Appropriate rehabilitation, especially the correction of ametropia, can significantly improve VRQL as revealed by the self-assessment of POAG patients.

异型结构多视角点云配准方法研究

针对异型结构全体积质量缺陷检测时需要可靠的结构外表面空间位置信息,提出一种高度还原异型结构真实三维场景的方法。该方法首先提取点云数据中的特征点后通过快速点特征直方图(fast point feature histograms,FPFH)描述特征点,接着采用随机采样一致性(random sample consensus,RANSAC)算法对点云进行粗配准,随后采用Iterative Closest Point算法进行精配准,来对采集到的点云数据进行拼接,最终得到完整异型结构承载件外表面点云数据;实验结果显示,所提出的算法和传统ICP配准算法比较精度提升了74.3%,与RANSAC+ICP配准方法提升了29.5%。优化后的算法在点云配准方面表现出很好的鲁棒性,为实际应用提供了极大的指导价值,能够显著提高点云配准的效率。

双矢量定姿在煤矿掘进机姿态测量中的应用

针对现有巷道掘进机的姿态测量手段中普遍存在的高成本和误差累积等问题,文中提出了一种基于双矢量定姿原理的姿态测量算法。通过在巷道掘进环境中分别对重力矢量和光矢量进行构建与感知,利用惯性倾角测量和双目视觉测量技术,基于矢量元素分别在导航坐标系和掘进机载体坐标系中的数学表达,可实现掘进机载体坐标系相对于巷道导航坐标系的姿态解算。利用倾斜仪和双目相机组成的测量装置对指示激光和重力矢量进行测量,结合双矢量定姿算法即可完成掘进机机身的姿态解算。文中设计了静态重复性精度测量实验,结果表明该方法的姿态角重复性测量精度为0.0662°。利用蒙特卡洛方法对可能会引入的误差源进行仿真分析,结果表明误差对方位角、俯仰角以及滚转角的影响分别为0.7864°、0.4548°和0.4765°。

倾斜角度飞机电传电位计自适应检测研究

现有的方法对倾斜角度拍摄的电传电位计图像的圆心坐标及凹槽角度检测存在较大的位置误差与角度误差,无法满足实际的使用需求。针对倾斜角度拍摄电传电位计时测量圆心坐标及凹槽角度偏移量较大的问题,提出倾斜角度飞机电传电位计自适应检测研究方法。通过图像预处理与边缘检测等方法初步得到飞机电传电位计的圆心及角度信息,提出圆心偏移矫正算法与角度偏移矫正算法对电传电位计圆心坐标及凹槽角度进行矫正,进一步提高电传电位计的检测精度。本检测算法与单应性检测算法作对比实验,结果表明:本算法对圆心距离误差最大为0.21 mm,凹槽弧度误差最大为0.72°。相比于单应性变换法在圆心平均误差下下降了0.09 mm,角度平均误差下降了0.38°,满足实际使用要求。

基于单目视觉实时测量桥式起重机负载摆角

针对目前基于视觉的桥式起重机负载摆角测量方法实时性较低,且没有考虑由运动模糊导致的测量精度下降问题,将一个对旋转和倾斜不敏感的球形标识物安装在负载上,设计一种计算灰度概率分布特征余弦相似度的方法,结合卡尔曼滤波器实时跟踪标识物。提出一种基于背景灰度值的局部自适应分割算法,使模糊边缘变清晰。从感兴趣区域(region of interest,ROI)的中心向周围8个方向寻找灰度梯度最大的点作为模糊图像的边缘点,对这些点采用最小二乘法进行拟合确定标识物位置。通过几何关系模型计算负载摆角。实验结果表明,本文方法在图像模糊情况下的测量精度和实时性能更优。

大视场三维姿态角光学测量系统设计

三维姿态角光学测量通过对物体表面的光学图像处理,实现对物体的角度姿态测量;为提高目标三维姿态角光学检测的准确性,提出基于立体视觉的大视场三维姿态角光学测量系统设计方法;利用双基准平行准直光源与姿态敏感器,通过图像传感器、USB接口芯片等部件实现分割光斑、质心定位等功能;在Linux内核基础上设计信号收集、数据移植、串口通信、姿态角分析4个软件模块,同时引入立体视觉算法探究靶标点和图像像点对应关联,运用视差定理确立空间角度的三维坐标,实现大视场三维姿态角测量;实验结果证明:所建系统姿态角标定误差小、时间同步性强,测量累计时间低于15 s,具有较高的测量精度和鲁棒性,为机械设备精密部件尺寸测量提供了一种有效的技术手段。

双目视觉成像法检测PC构件表面粗糙度试验研究

通过与铺砂法对比,探究了双目视觉成像法在检测预制混凝土(PC)构件结合面粗糙度方面的可行性,分析了构件表面潮湿程度、光照强度和测试角度对双目视觉成像法检测结果的影响。结果表明:采用双目视觉成像法检测构件结合面粗糙度是可行的,能够满足工程检测需要;采用双目视觉成像法检测不受环境光照强度的影响,但需保证构件表面没有积水,且构件与测量镜头应保持水平,否则需对测试角度进行合理修正。

视感知觉训练对间歇外斜视患儿术后视功能恢复的影响

目的:探讨间歇性外斜视患儿术后进行视感知觉训练的效果。方法:选取2020年4月至2023年4月郑州市第二人民医院收治的80例间歇性外斜视患儿作为研究对象,随机数字表法分为两组,每组各40例,对照组采取矫治术及配镜治疗,观察组在此基础上增加视感知觉训练,比较两组患儿的视功能、斜视度、知觉眼位偏移情况及立体视觉。结果:观察组术后7d视功能Ⅲ级37.50%,术后1个月Ⅲ级57.50%,6个月Ⅲ级82.50%,显著优于对照组(P<0.05)。观察组看近和看远的斜视棱镜度、斜视圆周度较对照组明显减小,融合范围较对照组明显增加(P<0.05)。术后1个月、6个月,观察组患儿知觉眼位的水平和垂直偏移显著低于对照组(P<0.05)。黄斑中心凹立体视比较,术后1个月观察组与对照组分别为60.00%、30.00%,术后6个月分别为65.00%、37.50%,差异有统计学意义(P<0.05);无立体视比较,术后1个月观察组与对照组分别为2.50%、25.00%,术后6个月分别为5.00%、25.00%,差异有统计学意义(P<0.05)。结论:针对间歇外斜视患儿实施视感知觉训练可促进术后视功能的改善,减小知觉眼位偏移程度,促进立体视觉恢复,防止眼位回退,减少无立体视觉。

高眼压状态下原发性急性闭角型青光眼手术治疗的效果研究

目的探讨对高眼压状态下原发性急性闭角型青光眼患者实施手术治疗的临床效果。方法回顾性选取2021年8月—2023年9月莒县中医医院收治的83例高眼压状态下原发性急性闭角型青光眼患者的临床资料。依据手术方法分组,参照组(41例)选择小梁切除术完成治疗,研究组(42例)选择激光虹膜切除术完成治疗。比较两组的手术疗效、裸眼视力、并发症以及眼压控制情况。结果研究组治疗总有效率为97.62%(41/42),高于参照组的80.49%(33/41),差异有统计学意义(χ^(2)=6.298,P<0.05)。术前,两组的裸眼视力以及眼压控制情况对比,差异无统计学意义(P均>0.05),术后研究组各时间段的裸眼视力以及眼压控制情况均优于参照组,差异有统计学意义(P均<0.05)。研究组并发症总发生率低于参照组,差异有统计学意义(P<0.05)。结论对高眼压状态下原发性急性闭角型青光眼患者实施手术治疗后,患者的裸眼视力以及眼压水平得到改善,还降低了并发症发生率。

降低介入诊疗过程中患者接受辐射剂量的研究

目的探讨采用平板大C介入诊疗时降低患者所接受辐射剂量的方法与技术。方法采用平板大C自身所具有的辐射监测功能记录辐射剂量率。研究者依次改变水模、球管、平板探测器之间的距离,并采用不同的曝光模式,测量并记录相对应的剂量率。将平板倾斜不同角度和改变视野(FOV)大小,测量并记录不同曝光模式所产生的剂量率。结果当水模与球管间距离一定时,平板离水模距离越近其辐射剂量率越小。同样条件下,FOV值越大,剂量率越小;倾斜角度越大,剂量率越大。相同曝光模式下,帧数越小,剂量率越小。其他条件相同时,数字减影的剂量率高于其他曝光模式。结论在介入诊疗时,合理调整影响辐射剂量的因素,可有效降低患者的整体辐射水平。

关于人体头部最佳转角及视野的研究

人体头部转角及视野的研究是人机工程学领域一项重要内容。本文在指出目前关于人体头部转角及视野研究中存在的不足基础上，用实测统计的方法对人眼正常转角及视野的最佳值进行了研究，得出了一系列规律性的新结论。

新型仿生偏振测角传感器及角度误差补偿算法

沙漠蚂蚁神奇的导航本领为我们研制新型导航传感器提供了有价值的技术参考。分析了沙漠蚂蚁利用天空偏振光分布模式导航的机理,设计了一种新型的仿生偏振测角传感器。提出了一种新的航向角度求解方法,给出了一种基于最小二乘支持向量机航向角输出误差补偿算法。利用精密旋转测试台进行了室外航向角度输出测试,实验结果证明了角度解算方法是可行的,角度误差补偿算法是健壮有效的。

大尺寸空间异面直线夹角的检测

针对实际工程中相距数米至数十米的若干几何元素之间的空间夹角,提出了大尺寸空间异面直线夹角激光检测系统的设计方案。首先,根据常见待测直线元素不同的实体存在形式,设计了相应的实体体现方法,并建立了异面夹角测量所需的公共基准;对于待测元素在公垂线方向距离很远的情况,采用单束线结构激光作为公共基准。然后,针对一个具体的工程实例,给出了系统检测框架的设计思路。最后,提出了公共基准与待测元素空间关系的获取方法。采用数字图像处理技术检测公共基准与各个待测元素构成的夹角并通过三角关系间接获得了待测元素异面夹角的检测结果。在30次系统测量中,系统重复性精度达到±0.020 85°,表明所提出的检测系统满足测量要求,验证了测量原理的可行性。

基于立体视觉的旋翼共锥度动态测量系统精度分析

为了提高基于立体视觉的直升机旋翼共锥度动态测量系统的精度和可操作性,全面分析了其测量误差。首先,介绍了测量系统模型及误差来源;其次,分析了双目立体视觉静态三维测量的误差;再次,针对旋翼共锥度的多目标动态测量特点,分析了系统安装误差对共锥度解算精度的影响;最后,利用原理样机进行了6 058次静态测量重复实验,通过统计分析可知静态测量误差小于1.4 mm。对动态测量误差进行了仿真实验分析,给出了各参数对精度影响的量化结果,为实际共锥度测量的误差控制提供了理论依据。在标记点安装精度小于10 mm的情况下,动态测量误差小于3.5 mm,合成产生的总测量误差小于4.9 mm,能满足旋翼共锥度动态测量精度要求。