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It is necessary to detect suspected defect regions in the radiographic weld images to find the type of flaw and its causative factors. This requires processing of radiographic images by a suitable approach. This paper presents an approach to process these radiographic weld images of the weld specimens considering morphological aspects of the image. The proposed approach first determines the flaw boundaries by applying the Canny operator after choosing an appropriate threshold value. The boundaries are then fixed using a morphological image processing approach i.e. dilating few similar boundaries and eroding some irrelevant boundaries decided on the basis of pixel characteristics. The flaws detected by this approach are categorized according to their properties. 相似文献
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This paper puts forward a new method of PCNN (pulse-coupled neural networks) image segmentation, in which the binary matrix of the ignition frequency matrix is employed, for the first time, to act as the final result of image segmentation. It gives the principles of PCNN parameter selection under the guidance of this process. The new method reduces the dependence of PCNN on parameters, improves the effect of image segmentation, and produces good results after being applied to image recognition of weld seam of oil derrick welded by arc welding robot. 相似文献
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干式高压TIG焊接法是海底输油(气)破损管道修复所用的重要的、焊接质量较高的连接方法,而自动化焊接又是解决潜水员焊接效率低下的有效途径,焊缝跟踪技术则是保证焊接过程正常进行和焊缝质量的关键技术.设计了能克服环境压力影响的CCD图像摄取装置,研究了一套焊缝跟踪路径识别算法.运用直方图均衡化方法强化坡口与非坡口的差别,增加焊缝图像的理解性.提出了以图像灰度最低值拟合成的曲线将整个图像分为两个部分的图像分解法,提高了图像识别目标的焊缝坡口部分所占的比重,有利于二值化阈值的选取.采用基于数学形态学的二值图像边界识别方法分离出焊缝边界,用Hough变换法确定坡口边线位置,最后用图像分解逆过程经合并后识别出坡口所在的位置.所提出的方法组合后抗干扰能力强,计算速度快,为进一步实现自动化焊接奠定了基础. 相似文献
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采用数字图像分割和亚像素边缘检测等图像处理技术自动测量刀具磨损边界的磨损量并与刀具磨钝标准比较,判断刀具的磨损状态,实现刀具磨损状态的间歇式在线自动检测。针对刀具的边缘特征,运用了中值滤波、对比度拉伸、迭代自适应二值化、基于分水岭分割、Roberts边缘算子、图像匹配、Zernike正交矩边缘检测和曲线拟合等数字图像处理技术,完成了刀具磨损量微米级的高精度检测。 相似文献
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It is difficult to acquire satisfied weld pool image by CCD sensor during gas metal arc welding(GMAW), for arc disturbs violently, welding current is great and working frequeacy is high. By using CMOS vision sensor to GMA W process, the vivid weld pool image is collected at any time, furthermore, whose gray compression ratio is controllable by sensor hardware circuit developed. Acquired weld pool image is firstly pre-processed by using Wiener filter and Ostu threshold segmentation algorithm. Subsequently separation between weld pool intage and cathode mist region is conducted by means of mathematical morphological algorithm, and the edge of weld pool image is extracted by using Prewitt algorithm. 相似文献
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提出一种将点焊过程动态电极位移信号转化为二值图像的方法.基于图像特征分析,从焊点样本电极位移二值图像中提取出15个隐含特征.针对一系列对应不同焊接质量焊点样本电极位移二值图像特征,利用主成分分析消除图像特征间的互相关性,建立了基于最小风险贝叶斯图像识别技术的焊点质量分类器.分类器有效性测试结果表明,电极位移信号二值图像尽可能多的保留了焊点质量信息,特征提取算法简单、高效、易于实现;同时在小数据样本情况下,贝叶斯图像识别技术能够快速、准确地评判焊点质量,有较好的应用前景. 相似文献
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超声无损检测已被广泛用来检测材料内部的缺陷,然而对缺陷性质的识别始终是检测的难点,为此研究了一种基于超声信号和图像融合的焊缝缺陷识别新方法.该方法充分利用检测数据,通过对缺陷回波信号特征与缺陷形态特征的数据融合,实现了焊缝缺陷的有效识别.利用自主研制的超声成像手动检测系统对含有气孔、夹渣、裂纹、未焊透和未熔合五类典型焊接缺陷的焊件进行了检测,分别提取缺陷的超声回波信号特征和缺陷图像的形态特征,构建神经网络实现超声信号和图像特征的数据融合.结果表明,该方法实现了多类缺陷的识别,提高了缺陷识别率,有助于焊缝质量评定. 相似文献
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开发了一种基于环形激光的视觉传感器并用于机器人焊接中的焊缝定位与跟踪,重点研究了在无弧光和弧光条件下焊缝图像滤波与图像分割等技术,解决了传感器图像采集与处理所面临的问题.在分析了最大类间方差自动取阈法、模糊簇聚方法的基础上,提出了一种基于灰度最大值统计与分区的两步法自适应阈值分割技术.结果表明,在无弧光条件下,利用灰度最大值统计方法获得了满意的分割效果,结合灰度最大值统计与区域分割技术适用于弧光条件下焊缝图像的分割,这两种自适应分割方法简单方便,优于传统的最大类间方差自动取阈法与模糊簇聚方法.此外,通过顺序统计量滤波技术很好地解决了光线弱化问题. 相似文献
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H. J. Zhang F. J. Wang W. G. Gao Y. Y. Hou 《Science & Technology of Welding & Joining》2014,19(3):242-249
To improve the efficiency of acquiring monitored features and present a reliable quality assessment method for resistance spot welding, a novel method for converting the electrode displacement signal into binary image is proposed. The probabilistic neural network is adopted to provide a probabilistic viewpoint and a deterministic classification result of weld quality when the image characteristic of displacement signal is selected as monitored features. Test results of the classifier demonstrate that it is feasible and reliable to utilise binary image of the displacement signal to evaluate weld quality. The method reserves weld quality information as much as possible and it avoids complex algorithm for extracting and selecting monitored features. At the same time, when there are small samples, the classifier can identify good or bad weld rapidly and accurately even though the weld is from abnormal welding process, such as expulsion, current shunting and small edge distance condition. 相似文献
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采用基于形态学增强和面积重构预处理的分水岭变换方法,对异种材料连接界面的超声检测图像进行了自适应分块阈值化分割处理.为了验证无损检测处理结果的可靠性,根据铜钢堆焊界面检测图像特征,对堆焊接头进行抽样破坏检测.结果表明,通过形态学增强和面积重构的预处理可有效抑制经典分水岭算法的过度分割,实现了检测图像按缺陷的分布特征进行自适应分块,进而通过阈值化分割,达到了超声弱信号缺陷的有效提取与量化的目的.经破坏性试验验证,该方法具有较高的检测可靠性. 相似文献
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设计了一种视觉传感器同时采集熔池和焊缝轮廓, 并提出一种基于视觉注意机制的机器人厚板焊接焊缝轮廓的提取方法. 该方法以图像的亮度信息和方向信息作为初级视觉特征,并以焊缝图像作为亮度特征图,把对焊缝图像进行膨胀处理再进行Gabor滤波的结果作为方向特征图. 对上述两种特征图进行显著性度量,然后对度量结果进行自适应特征融合获取综合显著图,并对其进行阈值分割和最近邻聚类. 结果表明,最后在所有类别中以成员数最多的类所覆盖的区域作为最先被注意的区域,而其包含的数据即为焊缝轮廓信息. 相似文献
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Bubble size estimation using interfacial morphological information for mineral flotation process monitoring 总被引:2,自引:0,他引:2
To relate froth structural information with mineral flotation performance, segmentation analysis was performed on froth images characterized by fully occupied convex bubbles with white spots effect. An improved valley edge detection method was proposed to extract structural features and overcome fake white spot edges seriously affecting the segmentation performance. After preprocessing, detection template was designed based on the local minimal intensity, and a binary image containing segmented boundaries was obtained by applying logical rules, thinning and filtering. Statistical features such as bubble size were estimated for control purpose. Experimental results demonstrate that the proposed method avoids over-segmentation or ill-segmentation caused by uneven illumination, and the industrial application reveals the reliability of bubble size estimation. 相似文献
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通过对管道全位置熔化极气体保护焊(gas metal arc welding,GMAW)熔池图像的研究分析,发现并验证了其根焊熔池图像尖端与焊缝坡口中心位置重合的现象,依据此规律性特征,提出了一种基于熔池图像尖端信息的焊接偏差测定方法.该方法的基本原理是,在对焊接过程熔池CCD图像进行中值滤波、小波变换、连通区域分割等图像处理后,以搜索算法测得的根焊熔池图像尖端位置信息作为焊缝坡口中心位置的坐标值,此值与焊丝中心坐标值之差即为焊接偏差量.试验证明,此方法能从根焊熔池图像中实时测定焊接偏差量,为实现机器人自动焊缝跟踪控制提供了可靠依据. 相似文献
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针对焊接过程中熔透及焊缝背面成形难以直接检测的问题,通过焊件正面和侧面的传感特征信息,对焊件背面的焊缝宽度进行预测. 用视觉传感器获取激光焊接过程中包含焊接特征信息的图像,对图像进行分割分层、模式识别和空域图像处理,准确提取焊接特征信息,发现焊接特征信息随着焊接路径的变化有着相应的变化趋势. 建立包含两个隐含层的贝叶斯神经网络,用提取到的9组特征信息作为输入,对焊件背面焊缝宽度进行预测. 通过10组焊件背面焊缝宽度的预测值与实际值的比较,验证了贝叶斯神经网络具有良好的预测能力,在焊缝不理想的状态下,也具有较好的预测能力. 相似文献
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为提高X射线图像缺陷自动识别的能力与图像分割的效果,提出了一种基于主成分分析法的X射线焊缝缺陷图像增强与分割算法。该算法首先通过计算图像的协方差矩阵特征值与其对应的特征向量,并根据特征向量分布,选择感兴趣区域即图像中的焊缝部分,从而减少图像处理的计算量;其次通过分析特征值累计百分比和试验结果,筛选出最佳的特征向量,对图像进行基于主成分的重构;最后采用Otsu阈值分割法,对重构后的图像进行分割。试验结果表明,该算法在对比度低、噪声严重的X射线缺陷图像分割中有很好的应用效果。 相似文献