一种自动读取指针式仪表读数的方法

为解决变电站中自动化监控仪表读数的问题,提出基于机器学习和图像处理算法的指针式仪表自动读数方法,由仪表检测和指针识别两个阶段组成。使用全卷积网络(fully convolutional networks,FCN)对输入图像进行语义分割,以检测仪表的位置并提取仪表部分的图像。利用直方图均衡化、中值滤波和双边滤波减小光照和阴影对指针识别的干扰,并利用仿射变换矫正拍摄时的倾斜,再结合改进的霍夫变换识别仪表中指针的位置,从而计算指针角度获取读数。结果表明,对于自然场景中变电站中的指针式仪表,本研究能很好地检测出仪表并识别出指针的读数,对于光照和阴影等干扰具有良好的鲁棒性,可以显著减少变电站巡检人员的工作量,提高工作效率。     

指针式仪表自动识别装置的设计

针对指针式仪表人眼读数效率低,不能转化成数字信号输入计算机,提出一种基于Hough变换的指针式仪表自动判读方法.该方法运用图像减影技术,通过调节图像分辨率实现指针的检出,再利用Hough变换做峰值检测、线检测和链接,通过转换偏转角度的基线位置,确定出仪表指针的读数.实验表明,该方法能快速有效地完成指针式仪表的自动判读,且最大不确定度明显优于人眼的识别,具有较高的精度.     

压力表图像自动识别系统研究

为了提高仪表人为读数的速度和精确度,提出首先对仪表图像进行二值化、滤波等基本处理;然后通过图像分割得到感兴趣的表盘区域,经过坐标平移翻转和极坐标变换的归一化算法,将圆形表盘转化成矩形指针表盘;再利用图像拼接算法得到无指针的表盘刻度矩形图像,并且通过直线扫描出每个刻度线;接着通过模板匹配,将待检测图像与无指针模板对比,从而检测出图像指针位置信息,得出指针读数。实验结果表明,采用这种图像处理技术使得识别速度更快,精确度也更高。     

基于嵌入式ARM的指针式仪表读数的识别研究

指针式仪表自动读数识别,是实现各种指针式仪表自动检定最重要的基础．针对嵌入式ARM系统,采用了一种适合实际设备运行的指针角度识别算法——差影法,并利用最小二乘法拟合指针直线方程．系统充分利用图像动态采集设备和基于多线程系统平台,把图像处理的算法和特征提取的算法进行优化结合,使得采集和判读以多线程方式并发执行．该系统实时性较好、误差小,通过实验结果证明这种算法对于嵌入式ARM系统下的指针式仪表读数的识别具有高效性．     

汽车仪表指针识别方法研究

利用减影法和Hough变换对指针式汽车仪表指针的识别进行研究。PCI-6024E数据采集卡发出标准信号驱动汽车仪表,由CCD摄像机获取汽车仪表图像传输至计算机,应用中值滤波、二值化和细化对仪表图像进行预处理。然后根据减影法、Hough变换提取目标信息,确定仪表读数。实验结果表明,该方法简便、精度高。     

基于颜色提取方法的仪表彩色指针识别

主要论述了利用颜色提取及图像分割技术对汽车仪表指针位置进行识别处理的原理、步骤以及具体的实现过程.通过使用彩色提取和形态学图像处理技术,成功地提取了仪表盘中红色的指针,确定圆心并利用角度法计算出指针仪表读数.颜色提取方法为 HIS颜色空间的坐标区域表示法,与常见的先把仪表图像转化成灰度图再进行处理的方法比较,此方法对于彩色指针仪表的识别更简单有效.     

颜色分割和拟合椭圆相结合的指针检测方法

针对目前汽车指针式仪表读数识别由人工检测,导致错检率高的问题,提出一种将颜色分割和拟合椭圆相结合的指针检测方法。首先根据汽车仪表指针颜色鲜明的特点,在充分保留图像原始信息的情况下,将图像由RGB颜色模型转换到HSI颜色模型中,根据色调设定阈值,对图像进行分割。然后根据指针细而长的特点,用优化的最小二乘法将指针图像拟化成椭圆,计算椭圆长轴与X轴夹角。最后根据椭圆中心和仪表的圆中心相对位置判断象限,确定指针的偏转角度,与标准表的偏转角度做比较,从而判断是否合格。实验结果表明,该方法对于彩色仪表的指针偏转角度检测,简单有效,具有很好的鲁棒性。     

基于机器视觉的汽车仪表指针检测方法

针对目前汽车指针式仪表读数识别由人工检测,导致错检率高的问题,提出一种基于机器视觉的指针检测方法。首先采用最小灰度相减法从两张背景相同的图像中提取无指针图像,以此为模板,让待检仪表与之进行匹配,矫正位姿。然后通过剪影法提取出仪表指针,二值化,闭运算后将指针用最小二乘法拟化成椭圆,利用椭圆长轴与水平线的夹角计算偏转角度。最后与标准表的偏转角度做比较,从而判断是否合格。实验结果表明,该方法可有效解决对于工艺偏差或设备轻微抖动造成的指针偏转测量有误的问题。算法稳定可靠,误差较小。     

基于图像处理技术指针表的自动识别

介绍了一种运用计算机图像处理技术对指针式仪表进行自动识别读数,以实现指针表自动检定,重点介绍了检定过程中指针示值自动识别读取数据来代替人工识别的判读方法。研究并设计了采用CCD摄像头摄取表盘图像,经计算机进行图像识别及数据处理实现仪表指针自动读数,从而避免了传统人工判读方法受工作人员与仪表盘的距离和角度等主观因素导致判读的数据误差较大、效率低、可靠性不高的影响,该方法不仅解决了实际应用中有关模拟指针式仪表的检定自动化问题,而且有利于大量信息的及时采集和统一管理。     

基于改进Canny检测与Hough变换的仪表图像识别算法

针对发电厂中指针式仪表数量多、周围环境复杂、灰尘污染等因素导致获得的图像含有大量噪声从而影响仪表读数识别精度的问题,提出了一种改进Canny边缘检测算法,通过采用5×5邻域计算像素梯度幅值的方法,提高了边缘检测精度,并采用自适应双阈值选择法,有效避免了传统Canny算法易出现伪边缘、边缘信息多等现象,结合Hough变换技术提取仪表指针信息,提高仪表识别精度。经实验对比验证,该算法检测效果优于传统Canny算法,仪表读数识别精度达到95%。     

Medium-range order clusters in metal melts

Structures of molten metals Cu and Al, alloys Cu-Al, Al-Ni, Al-Fe and, Al-Si were investigated by using high temperature X-ray diffractometer. It has been found that there are not only short-range order structures (SRO) but also medium range order structures (MRO) in Cu-Al, Al-Ni, Al-Fe alloy melts. There are only short-range order structures in the pure metals Cu and Al and Al-Si alloy melts at different temperatures. It has also been found that the presence and the disappearance of the MRO structures in molten metals are a function of temperature. Moreover, the pre-peak in the structure factor is an indication of MRO in molten metals. There is a pre-peak in each structure factor S( Q) of Al-Fe alloy melt containing 14 wt% Fe, 16 wt% Fe and 19 wt% Fe at 1550℃, showing that there are the medium range order structures in these alloy melts. For Al-35wt% Ni alloy, the pre-peak exists in S(Q) when the temperature is lower than 1300?, and it is weakened drastically when the temperature surpasses 1300℃. The     

Al-Cu-Mg硬铝合金TIG焊焊接接头的组织与力学性能

为了研究Al-Cu-Mg硬铝合金TIG焊焊接接头的组织与力学性能,采用ER4043焊丝对2A12硬铝合金进行了焊接实验.利用光学显微镜、扫描电子显微镜、透射电子显微镜、能谱分析仪和硬度计对Al-Cu-Mg硬铝合金的组织和力学性能进行了表征.结果表明,焊缝的强度和塑性较低,焊缝边缘为柱状晶,中心为枝晶组织,晶界存在大量低熔点共晶体.近缝区存在明显的晶界液化现象,晶粒为圆润的等轴晶,焊缝的硬度大幅度下降.固溶区焊缝的硬度和母材相近,基体中存在大量的针状S'相,可对该区域起到强化作用.过时效区基体软化现象比较严重,存在很多S(Al2Cu M g)相.     

熔体热历史对Al-10%Cu合金组织和性能的影响

Al-Cu合金是工业上应用广泛的合金.为了提高Al-10%Cu合金的力学性能,研究了熔体过热处理和高低温熔体混合处理对Al-10%Cu合金组织和性能的影响.结果发现：过热处理和高低温熔体混合处理能细化Al-10%Cu合金的凝固组织、提高其力学性能.熔体在900℃下过热处理后,其抗拉强度和延伸率最大,分别为171.9MPa和2.87%.高低温熔体混合处理对合金组织和性能的影响明显强于熔体过热处理.高低温熔体混合处理后,Al-10%Cu合金的抗拉强度和延伸率分别被提高到231.9MPa和3.62%.     

工艺参数对镍基单晶高温合金DD98瞬态液相连接组织的影响

利用Ni-Cr-Co-W-B合金作为中间层合金对DD98镍基单晶高温合金进行瞬态液相连接,利用光学显微镜和扫描电镜对不同连接温度和时间下的接头组织进行观察分析,结果表明,连接区域由连接区,扩散区和基体区组成,随着连接温度的提高或保温时间的延长,连接区上的残余液相宽度逐渐变窄.     

Microstructure and property of the Ti-24Al-15Nb-1.5Mo/TC11 joint welded by electron beam welding

The Ti-24Al-15Nb-1.5Mo alloy,in the as-forged and heat-treated states,was joined to the as-forged TC11 titanium alloy by electron beam welding with the heat inputs of 135 and 150 kJ/m.Then the microstructure and property of the Ti-24Al-15Nb-1.5Mo/TC11 welding interface were investigated.The results show that the phase constitution of the weld is not related to the heat input,and is mainly composed of α' phase.Moreover,the intermetallic phases of Ti2AlNb,MoNb,Nb3Al,and TiAl3 are formed in the weld zone.There...     

Application of the annexation principle to the thermodynamic property study of ternary metallic melts In—Bi—Cu and In—Sb—Cu

Based on the phase diagrams,measured activities and the annexation principle,calculating models of mass action concentrations for In-Bi-Cu and In-Sb-Cu melts have been formulated.Calculated results not only agree well with practical values,but also obey the mass action law,showing that the deduced model can reflect the structural reality of given melts and that the annexation principle is applicable to these two ternary metallic melts.So long as there is one from three binary systems constituting the ternary melts,in which the activities of one component exhibit positive deviation relative to Raoultian behavior,heterogeous melts inevitably would form,soheterogeneous calculating model should be used to calculate their mass action concentrations.On the contrary,if all the binary melts are homogeneous and their activities exhibit negative deviation with respect to the Raoult‘s law.then the ternary melts formed from them will certainly be homogeneous,hence single phase model should be applied.     

Influence of elemental iron on hydrogen content in superheated aluminum-iron melts

The hydrogen content in liquid binary aluminum alloys with 1,3,5 and 8 wt% iron has been determined in the temperature range from 973K to 1103K. The hydrogen content in molten Al-Fe alloys increases remarkably when the temperature of the meh rises to about 1053K. This work indicates that the alloying element iron plays an important role in hydrogen content in snperheated Al-Fe alloy melts below about 1053K. The results make it clear that the hydrogen content in the mekt ahuminum reduces with the increasing element levels. A conclusion is drawn that the degree of gassing in molten AL-Fe alloys is hound up with the properties of oxide film of aluminum alloy melts. The element iron has no effect on the compact stntcture of oxide film in aluminum melts. The effects of alloying element are theoretically analyced in terms of Wagner interaction parameter. According to the values of the first order interaction parameter, it is concluded that the interaction between iron atom and aluminum is much stronger than that between hydrogen atom and ahanintum, and the addition of the alloying element decreases the affinity of liquid aluminum for hydrogen.     

Effect of low temperature aging on microstructure and mechanical properties of super-high strength aluminum alloy

The effects of heat treatment on the microstructure and mechanical properties of two alloys, namely Al- 12.2%Zn-2.48%Cu-2.0%Mg-0.15%Zr-0. 166%Ag（alloy 1）, and Al-9.99%Zn-1.72%Cu-2.5%Mg-0.13%Zr（alloy 2） were investigated. The results show that low temperature aging after promotive solution treatment can increase elongation without the loss of strength for the studied alloys. The optimum aging treatment （T6） for alloy 1 and alloy 2 is 100 ℃/80 h and 100 ℃/48 h, respectively. Compared with other heat treatment alloys, alloy 1 and alloy 2 show super-high tensile strength up to 753 MPa and 788 MPa, remaining 9.3% and 9.7% elongation under T6 condition, respectively. During aging, trace addition of Ag enhances the formations of GP zone and metastable phase, and stabilizes GP zone and metastable phase to a higher temperature. Trace addition of Ag prolongs the aging time of reaching the peak strength and delays over-aging condition of the alloy. However, trace addition of Ag promotes the formation of coarse constituent in the alloy and consumes hardening alloying elements of Zn and Mg. Moreover, the addition of the transition element Zr in 7000 series super-high alloy forms incoherent Al3 Zr dispersoid which can serve as nucleation sites for nonuniform precipitation of η phase during aging process. The higher the aging temperature, the greater the tendency for nonuniform precipitation of η phase.     

Carbon Solubility and Mass Action Concentrations of Fe-Cr-C Melts

An empirical equation of carbon solubility in Fe-Cr-C melts is regressed based on the experimental data from references. Acalculating model of mass action concentrations for these melts is formulated on the basis of the coexistence theory of metaIlic melts in-volving compound formation, the phase diagram of Cr-C system as well as thermodynamic data of Fe-Cr-C melts. According to the mod-el, the standard Gibbs free energies of formation of CrC and Cr3C2 are obtained. Satisfactory agreement between the calculated and me-asured values shows that the model can reflect the structural characteristics of Fe-Cr-C melts.     

Application of annexation principle to the study of thermodynamic properties of Ag-Bi-In metallic melts

Based on the measured activities, the phase diagrams and the annexation principle, the calculating models of mass action concentrations for Ag-Bi and Ag-Bi-In melts have been formulated. The calculated results agree with practice and obey the mass action law, showing that the models formulated can reflect the structural characteristics of both melts. Meanwhile, it confirms that annexation principle is applicable to the Ag-Bi-In metallic melts. The melts involving eulectic which give rise to phase separation, and in which activities exhibit positive deviation from Raoult's law is the basic cause of melts transforming from homogeneous to heterogeneous ones.