利用火焰图像重建三维温度场的模型和实验

火焰温度场的非接触测量对于能源领域的生产和控制具有重要意义，根据摄像机光学成像模型和辐射传递原理，提出了根据火焰图像重建火焰三维温度场的模型和方法．采用代数重建技术ART对温度场控制方程进行求解，在煤粉试验炉上进行了三维温度场测试，测试结果为进一步研究温度场重建奠定了基础。     

运用代数迭代技术由火焰图像重建三维温度场

在运用图像处理的方法测量火焰温度场的研究中,从摄像机获取的二维累积图像中重建出包含每个断面温度分布的三维温度场,是关系到能否投入实际应用的关系问题,结合扇形计算机断层成像原理和火焰辐射传递方程,推导出辐射强度随投影路径衰减的控制方程。将火焰断面网格化之后,运用代数重建技术对离散方程温度和辐射衰减系数同时迭代求解。在油煤混烧的燃烧器上运用该方法进行实验研究,并结合算法的数值模拟,对其可能误差和改进方     

基于高速立体视觉系统的粒子三维运动研究

气固两相流中固体粒子三维运动轨迹是研究气固两相耦合关系、分析不同大小粒子分布和运动规律的核心参数,也是研究湍流涡结构作用力、边界层效应的一个重要依据.为此建立了微秒级单相机双视角三维流场成像系统,由单摄像机CCD靶面上同时获取的2个不同角度的两相流图像,通过粒子模式识别算法及粒子三维坐标的逆向投影重建算法,重建了两相流中固体粒子团的三维结构,并在此基础上提出了基于立体视觉原理的三维颗粒轨迹重建模型.     

火焰参数对辐射图像法不同测温模型的影响

对火焰温度分布的实时测量能够了解燃烧过程、验证燃烧机理、预防工业事故、优化燃烧设备。图像法测温在工业现场的火焰三维温度测量上有明显的优势,但通常均考虑火焰为均匀折射率介质,给测温结果带来了不可避免的误差。本文建立了梯度折射率介质下火焰的辐射成像模型和图像法测温模型,验证了方法的正确性,分析了火焰尺寸对成像的影响及炭黑颗粒浓度对温度场重建的影响。得出随着火焰尺寸的增大,图像强度随火焰尺寸出现先增大后减小的趋势,梯度介质模型与均匀介质模型的差异逐渐增大,随着炭黑颗粒浓度的增加,两种模型的重建精度逐渐下降。     

炉膛燃烧温度场三维可视化监测方法模拟研究

为了利用火焰图像监测装置检测到的炉膛燃烧辐射能分布图像信息重建三维燃烧温度场，作者提出了一种针孔成像条件下的快速方法计算CCD（Charge-Coupled Device，电荷耦合器件）靶面接收的辐射能。成像像素接收到的系统网格单元的辐射能的份额的计算结果和辐射能图像计算结果均体现了成像过程的方向选择性和辐射能传递规律的作用。针对炉膛燃烧三维温度场重建的严重病态问题建立了一种基于Tikhonov正则化的求解方法，对于单峰型三维温度分布重建模拟计算结果表明，即使辐射图像检测包含均方差达到0.11的误差，温度场重建误差仍能维持与测量误差基本相当的水平，温度分布可视化质量较高，各种图像检测组合方式的重建结果比较显示，炉膛四角沿高度方向每隔5m左右交叉对角布置两个辐射图像采集装置，能够获得较好的全炉膛温度场可视化结果。     

笼式光场相机的组装及其在火焰温度场测量中的应用

为了实现燃烧火焰的三维温度分布监测,本文结合光场成像和光学分层成像技术,发展了一种基于单光场相机的火焰温度场光场层析重建方法.针对燃烧装置与火焰特性设计并研制了笼式光场相机,建立了双火焰(乙烯/蜡烛)光场层析成像实验系统.利用笼式光场相机采集火焰光场信息,利用光场成像技术获取重聚焦图像,利用光学分层成像技术重建断面辐射...     

煤粉火焰实际成像过程模型

为了深入研究煤粉火焰的成像过程，不按照传统方法将煤粉火焰假设为灰性介质，而是将煤粉火焰考虑为三维吸收、发射、各向异性、散射的非灰性介质。用Monte Carlo方法对煤粉火焰的成像过程进行了模拟，提出了虚假物面成像的假设，并计算分析了虚假物面与摄像机镜头的距离对成像的影响。图6参10     

火焰图像检测器着火判据的设计与实验研究

锅炉火检系统是保障锅炉安全运行的重要检测设备。图像火检在８０年代出现后由于其准确性和直观性，成为火检系统的新趋势。同时，由于所需分析检测的信号扩展为二维图像信号，带来了实时处理大数据量的困难。在大量现场实验的基础上，提出了基于火焰锋面动态检测的着炎判据，综合考虑了火焰亮度、火焰锋面位置及其波动，明显改善了系统的报警速度和精度。判据的普和适性也很好。     

单光束激光散斑干涉法测量内燃机连杆的变形

本用单光束激光散斑干涉法测量了内燃机连杆的变形。中讨论了用激光散斑干涉法测量变形时，影响测量精度的各种因素，并认为变形测量的准确性主要取决于散斑干涉条纹间距和成像放大倍数的测量。为了准确测量条纹间距和成像放大倍数，中改进了测量方法，将再现的杨纸条纹用ＣＣＤ摄像机输入到计算机，用数字图像处理技术对条纹图进行处理，并用方法获取条纹间距，另外实物和散斑图像也摄入计算机，根据实物和像所占据的像素数得     

基于图像深度学习与三维电场仿真的电力用复合绝缘子缺陷挖掘分析

鉴于复合绝缘子运行环境差异较大、表面电场分布特征各异,亟需合理评估现役运行复合绝缘子运行状态。为此,首先应用紫外、红外成像技术对典型复合绝缘子进行观测形成电-热影像图谱数据库;然后应用小波成像技术对原始图像进行去噪处理,并基于聚类算法对复合绝缘子进行图像区域分割,联合视觉深度学习实现了复合绝缘子类型自适应识别和外轮廓匹配。同时应用三维建模技术对典型复合绝缘子电场分布规律进行仿真模拟,实现复合绝缘子高场强区域电场分布可视化;最终联合深度学习图像后处理结果和电场分布特征形成现役复合绝缘子运行状态评估策略。研究结果对于电力系统用复合绝缘子运行维护具有较好指导意义。     

搭载4K高清摄像系统ROV在长距离地涵水下检查中的应用

为实现深水环境中地涵缺陷检测,在ROV上搭载4K高清摄像头,基于高清成像,利用视频图像处理技术提高水下成像清晰度,实现水下涵洞缺陷图像智能检测,将搭载4K高清摄像头的ROV应用于运行60年,至今未进行过检查的距离长、水压大、能见度低的长距离地涵,全面了解其运行状况和缺陷情况,并通过潜水员人工复核,验证了测量结果的准确性。     

Unsteady correlation between pressure and temperature field on impinging plate for dual underexpanded jets

In this paper, dual underexpanded impinging jets are experimentally studied by measuring unsteady wall static pressure and temperature fields using high response semiconductor pressure sensors and infrared imaging camera(100 captures per sec) with dual converging sonic nozzles. The flow field is also visualized by means of high speed schlieren system (up to 70000 frame per second) to clarify the unsteady behavior of the jet structures such as barrel shock wave, and Mach disk. Experiments were performed with a blow down tunnel changing the parameters such as the nozzle to plate distance, the distance between the two nozzles, and wind tunnel pressure ratio. The nozzle to plate distance L and the distance between the two nozzles H are non-dimensionalized by the nozzle diameter D covering H/D=1.5, 2.0, and 3, L/D= 2, 3, and 4, and po/pb=1.0 − 5.0, where po and pb are stagnation pressure and back pressure respectively. Although the response of the infrared camera is quite different from that of the high speed camera, the unsteady correlation between the pressure and temperature fields is confirmed under some conditions. Also the high speed schlieren pictures and the wall static pressure fluctuations suggest that the generation of the Mach disk promote the unsteady behavior of the jets. After the confirmation of the correlation, a simple way to find the severe fluctuating region can be provided according to the two dimensional unsteady temperature images without a lot of unsteady pressure measurements.     

多喷嘴对置式气化炉撞击火焰三维温度场

基于多喷嘴对置式气化炉热态试验装置,以光学分层成像和Planck辐射定律为理论基础,建立了一种采用单套面阵CCD相机测量气化炉内三维温度场的方法.火焰监测系统安装在气化炉顶部以采集火焰图像,热电偶以及另一只相机与内窥镜组合以验证计算得到的温度场.结果表明,气化炉内整体温度维持在1,300,K左右,撞击火焰在喷嘴平面上下200,mm内形成1,950～2,150,K的高温区;该算法能够很好地还原炉内火焰的内部结构,较为准确地反映气化炉三维空间内各区域的温度分布.     

Effects of hydrogen and primary air in a commercial partially-premixed atmospheric gas burner by means of optical and supervised machine learning techniques

In order to ascertain the effects of the hydrogen addition and the primary air-fuel ratio on burner performance and emissions, we conduct tests on a commercial atmospheric gas burner using pure methane and a blend of hydrogen/methane. Relevant statistical image features are extracted from a UV–VIS camera equipped with narrow-band optical filters. Radical image results agrees with spectrometric data, showing the relevance of the OH¹ intensity radiation coming from the outer non-premixed zone. The double-cone flame structure is evident, showing a growing secondary non-premixed cone as the primary air-fuel ratio is decreased. In addition, the direct relationship found between flame radical imaging features and NO_x emissions has been used to develop a predictive model by integrating classification techniques and neural networks. The research confirms UV–VIS chemiluminescence imaging techniques as powerful tools aimed at combustion monitoring, with huge prospects of being integrated within advanced emission control techniques for commercial burners.     

高热流密度下R113核态沸腾中汽化核心密度的识别

1引言核态沸腾是一种被工业界广泛应用的传热技术,在冶金、化工、动力等领域有广泛的发展前景。其优点是能以较低的温差传递较多的热量。在核态沸腾中有相变发生,相变发生的地方是成核地点[1],称为汽化核心。汽化核心的研究对于核态沸腾技术的发展具有非常重要的意义。传统的拍     

ESPI testing of Arcton containers

The paper reports on the application of TV holography, more commonly known as electronic speckle pattern interferometry (ESPI), in the testing of Arcton bottles. A large number of Arcton bottles that have been returned to the factory for refilling exhibit dents of all sizes which occurred while in usage in the industrial environment.

A system comprising a pulsed ruby laser, a high resolution CCD camera and a computer with frame grabbing capabilities has been prototyped to test two bottles at a time. The testing consists of providing an initial no-load image which is captured by the speckle camera. A second image of the bottles under-load (small depressurisation), is subtracted from the first, giving good quality interference fringes. The resulting image clearly denotes regions of higher density fringe pattern centred around dents or irregularities of the cylindrical surface of the bottles. The operator homes in with a cursor to measure the fringe density which is compared with the allowable one and acceptance or rejection of the bottle is indicated on the pc's monitor. The whole operation takes place in less than 5 min and is controllable from the pc's keyboard.     

Applications of Electrical Capacitance Tomography in Two Phase Flow Visualization

The successful application of Electrical Capacitance Tomography (ECT) depends heavily on the image reconstruction speed and quality. The two requirements usually cannot be satisfied simultaneously. Also, for a large number of acquired 2D ECT images, a 3D presentation of them is much desired to track the variations of the material distribution in a third dimension. To facilitate ECT for practical flow analyses in process engineering, the authors have recently developed algorithms for 3D image presentation and for online iterative image reconstruction that only takes the same time as a linear back projection method but yields good image qualities as the Landweber iterative method does. The new methods have been successfully applied to visualize several classes of two phase flows, namely fluidization, cyclone separation, circulating rate determination in circulating fluidized beds, pneumatic conveying, rotating drum mixing. Special characteristics in each case have been discussed and valuable results are obtained, which are reported in this paper.     

Application of digital holography to circle flow bed boiler measurement

The spatial distribution of particles in the boiler is very important in the study on the circle flow bed boiler (CFB). Digital in-line holography technique was applied to obtain the spatial and diameter distribution of the particles inside the boiler. A HE-NE laser was used to illuminate the particles inside the CFB through two glass windows and the in-line diffraction pattern was recorded by a CCD camera. The diffraction can be interpreted as a convolution between a family of wavelet functions and the object function. So the three-dimensional (3D) images of the particles in the two-phase flow were reconstructed by the convolution between diffraction pattern and wavelet functions. The particle diameters and 3D coordinates were calculated from the reconstructed 3D images by a series of image-processing methods, followed by a discussion of the experimental results. Translated from Proceedings of the CSEE, 2005, 25(15): 111–115 [译自: 中国电机工程学报]