共查询到19条相似文献,搜索用时 250 毫秒
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针对小径管X射线焊缝图像缺陷检测精确率低的现状,通过对图像进行特征分析并结合稀疏字典学习,提出一种基于图像分割的小径管焊缝图像缺陷检测算法.首先,对小径管焊缝图像进行两步图像分割获得感兴趣区域;其次,提取焊缝缺陷,得到缺陷疑似局部图像;最后,提出以不同类型原子间相关性最小为目标的小径管焊缝缺陷字典矩阵数学模型并使用K-SVD算法进行求解,利用该字典矩阵实现圆形缺陷、线形缺陷和噪声的分类鉴别.为提高系统实时性,使用并行编程对图像分割算法进行加速.结果表明,改进后缺陷字典矩阵对圆形缺陷识别成功率为0.974,线形缺陷识别成功率为0.967,且具有较快的识别速度,实现了小径管焊缝图像缺陷的有效识别. 相似文献
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将目标检测网络Faster-RCNN应用在船舶焊缝X射线缺陷图像检测中,探讨了Faster-RCNN在X射线焊缝缺陷检测中的效果。针对船舶工业中的X射线焊缝图像,首先采用CLAHE方法对焊缝X射线图像进行预处理,并将焊缝中存在的气孔、裂纹、未熔合等5种具有典型特征的缺陷作为识别目标进行标注并对数据进行增强。在目标识别上,采用ResNet-50作为主干网络来减少梯度弥散现象提高模型准确率,并针对焊缝缺陷目标小的特点对RPN网络锚点参数进行改进优化,同时引入FPN网络提取缺陷特征。最后与其他检测算法进行对比,试验结果表明,该数据集在模型上的mAP值达到96.33%,可以满足X射线焊缝缺陷自动化辅助检测要求。 相似文献
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由于存在焊缝图像噪声强、不清晰、对比度低的问题,导致图像分割效果差,文中提出一种基于二元函数拟合的X射线焊缝图像缺陷分割方法。通过正弦变换函数对原始焊缝图像增强处理,使用B样条曲线拟合图像内的灰度曲线,计算高斯曲率与平均曲率得到焊缝表面图像边缘特征,通过二元函数得到不同类型的焊缝边缘数据,结合焊缝图像的表决图,完成对焊缝图像缺陷完美分割。试验结果表明,该方法分割精度高,且在缺陷类别识别和检测效果图上都要高于卷积神经网络算法、目标检测算法、多视觉成像算法的,证明所提方法分割效果好,有实际的应用价值。 相似文献
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汽车部件焊缝质量的人工检测效率低,精度差,且数据不易统计、存储及查询。将机器视觉技术引入汽车部件焊缝质量检测能够很好地克服上述缺陷,实现焊缝质量自动检测、判定、统计及查询。检测系统利用机器人手臂夹持视觉传感器与光源,对汽车底盘横向摇臂的焊缝分段采集结构光图像和LED光图像,根据不同图像特征设计适应性强的图像处理算法进行计算、判别。通过LED光图像可以识别焊缝缺失、表面气孔等缺陷;通过结构光图像可以测量出焊缝宽度和角焊缝厚度,并判定是否焊偏。试验结果表明,检测系统能准确高效地计算、判别焊缝的主要特征,适合在焊缝质量检测领域推广应用。 相似文献
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针对工业X射线焊缝图像对比度低、缺陷模糊且相对面积较小及难以识别的问题,设计了结合卷积神经网络的识别框架。根据缺陷图像特点,设计了对应的神经网络结构、卷积模板及池化模板的大小。在分析确定神经网络结构的基础上,卷积神经网络的灵敏度和训练算法也在文中一并给出。通过实例对神经网络结构进行了有效性的验证,缺陷检测准确率达97%,误报率仅为3%。同时,对适用于卷积神经网络进行识别的X射线焊缝图像进行了分析,发现灰度直方图有效信息跨度范围在50之上的卷积神经网络可以有效识别。文中所设计的神经络对X射线焊缝缺陷图像的识别可行、有效。 相似文献
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In this paper, the X-ray nondestructive test method of small defects in precision weldments with complex structure was presented. To resolve the difficulty of defect segmentation in variable grey image, the image processing based on Visual Basic programming method was adopted. The methods of automatic contrast and partial grey stretch were used to enhance the X-ray detection image which has relatively low contrast, then automatic threshold method was carried out to segment the two high intensity zones, and weld zones which contain the small defects was extracted. Smoothing and sharpen processing were proceeded on the extracted weld zones, and small defects in X-ray detection image of weldments with complex structure were segmented by using the method of background subtraction in the end. The effects of raster were eliminated, and because of that the image processing was only proceeded on the extracted weld zones, the calculated speed using the above provided algorithm was improved. 相似文献
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针对焊接过程产生的缺陷,提出一种磁光成像传感的模糊灰度变换和滤波反投影(FGT-FBP)重构检测方法. 研究焊接缺陷的几何特征,通过分析裂纹和未熔合两种不同焊接缺陷在交变磁场励磁下的磁光成像特征,设计模糊规则,对磁光图像进行模糊灰度变换. 增强磁光图像对比度,使焊接缺陷形态趋势可视化,实现描述磁光成像焊接缺陷细节的无参考型图像评估方法. 对FGT处理的焊接缺陷磁光图进行旋转投影,并经过快速傅里叶变换和改进的滤波器进行滤波去噪,消除伪影后进行反投影变换实现焊接缺陷图像的重构. 利用滤波反投影重构算法进行去噪,可有效突出焊接缺陷特征. 最后结合阈值分割和边缘检测实现焊接缺陷检测. 结果表明,该方法能较准确检测裂纹和未熔合两种焊接缺陷. 相似文献
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This paper presents a method for the automatic detection and classification of defects in radiographic images of welded joints obtained by exposure technique of double wall double image (DWDI). The proposed method locates the weld bead on the DWDI radiographic images, segments discontinuities (potential defects) in the detected weld bead and extracts features of these discontinuities. These features are used in a feed-forward multilayer perceptron (MLP) with backpropagation learning algorithm to classify descontinuities in “defect and no-defect”. The classifier reached an accuracy of 88.6% and a F-score of 87.5% for the test data. A comparison of the results with the earlier studies using SWSI and DWSI radiographic images indicates that the proposed method is promising. This work contributes towards the improvement of the automatic detection of welding defects in DWDI radiographic image which results can be used by weld inspectors as a support in the preparation of technical reports. 相似文献
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In ultrasonic time of flight diffraction (TOFD) D-scan image, only a small fraction represents defects, whereas the majority is redundant. Because of the low contrast between defect and background image, it is difficult to manually interpret TOFD image. In addition, due to the nature of the weak amplitude of ultrasonic diffracted signals, the human factor introduces inconsistency into the interpretation. In order to automatically distinguish weld defects from the D-scan image, a defect detection method based on image processing technique is proposed. First, image pre-processing including clutter and noise suppression is conducted. Second, information entropy based image segmentation technique is employed to extract defects in the pre-processed image. At last, mathematical morphology based post-processing is carried out. The experimental results show that with the proposed method, TOFD can be used for automatic weld defect detection with satisfactory level of reliability. 相似文献
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针对在强噪声、低对比度及复杂背景特征下X射线焊缝图像的缺陷检测问题,提出了去噪处理、焊缝边缘分割及缺陷检测的方法.用快速离散Curvelet变换和循环平移相结合的方法,对焊缝图像进行滤波去噪,同时对图像列灰度曲线用最大类间方差法提取焊缝区域.在图像预处理后,采用三阶Fourier曲线对图像列灰度曲线进行拟合并扩展到三维空间,构造出自适应阈值面,最后利用原图像与构造曲面三维灰度图的灰度值差异,准确分割背景与缺陷区域.结果表明,与传统缺陷检测算法相比,该方法能准确提取出焊缝缺陷,漏检率和误判率低,准确率可达95%. 相似文献
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In this paper, we describe an automatic detection system to recognise welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and the detection of weld defects. In a second stage, a set of geometrical features which characterise the defect shape and orientation was proposed and extracted between defect candidates. In a third stage, an artificial neural network (ANN) for weld defect classification was used. With the aim of obtaining the best performance of ANN three different methods for improving network generalisation was used. The results was compared with a method without generalisation. For the input layer, the principal component analysis technique was used in order to reduce the number of feature variables; and, for the hidden layer, a different number of neurons was used. 相似文献