共查询到19条相似文献,搜索用时 171 毫秒
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我国石油天然气输送管道分布广泛,发展迅速。管道的定期检测维护需求也不断上升。作为应用范围最广的管道内检测器,流体驱动式管道机器人的大部分核心技术被国外技术封锁,我国大力发展管道机器人检测技术十分必要。笔者结合近年来国内外相关设计成果介绍了流体驱动式管道机器人的发展趋势和现状,总结了目前流体驱动式管道机器人的结构分类,并整理出一条关于管道机器人结构设计的思路流程。希望对想了解相关信息和有相关设计需求的读者有所帮助。 相似文献
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近年来,随着海底管道服役年限的增加,发现的缺陷点危险程度越发严重。在海底管道缺陷点修复工程中,缺陷点的定位查找方法尤为关键,根据海底管道内检测数据,可以对海底管道缺陷点进行定位和查找确认。该方法在渤海地区海底管道缺陷点修复作业中已多次使用并取得良好效果,为类似工程项目提供了经验借鉴。 相似文献
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《化工机械》2016,(3):365-372
现有双腐蚀缺陷管道剩余强度评价规范大多以轴向均匀腐蚀为研究对象,评价双点蚀缺陷管道时结果偏保守,导致管材严重浪费。利用非线性有限元分析方法对含有交互影响双点蚀缺陷管道的剩余强度进行分析,验证了分析方法的可靠性。在此基础上,研究了轴向间距对带有相同尺寸双点蚀缺陷管道失效压力的影响,分析表明:当双点蚀缺陷轴向间距很近时,双点蚀缺陷管道失效压力会明显小于半径为两个点蚀缺陷半径之和的单点蚀缺陷管道的失效压力;0l_dl_s是相同尺寸双点蚀缺陷相互作用区间,在此区间内双点蚀管道失效压力随轴向间距系数呈对数函数形式;点蚀半径对双点蚀缺陷相互作用区间的影响大于点蚀深度的影响。 相似文献
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路面出现裂缝时人工检测不能有效地检测裂缝的特征,一般采取基于对比度增强和高斯滤波对图像像素增强的方法进行预处理来保障计算机分析结果。基于均值滤波算法进行降噪处理,采用Prewitt算子分割法和Otsu阈值分割算法对图像进行分割处理,得出明确边缘定位和图像去噪效果的路面裂缝图像,便于计算机进行分类和识别,提高路面裂缝的识别效率。 相似文献
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基于支持向量机的管道腐蚀超声波内检测 总被引:6,自引:4,他引:2
超声波检测是输油管道在线内检测的重要方法之一,由于管道内部检测环境复杂,使超声检测回波信号识别困难,其分类是一个高维分类问题。利用支持向量机在解决小样本、非线性、高维模式识别中特有的优势,直接采用表征超声回波形态的A扫描数据作为特征向量,将特征提取与模式分类统一进行,建立了管道腐蚀超声检测回波信号分类决策函数,实现了管道腐蚀缺陷识别。实验结果表明,该方法可以正确地分类识别管道腐蚀产生的突变界面,基于支持向量机的管道腐蚀超声内检测信号分类识别方法是可行、有效的。 相似文献
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随着油气管道安全性管理要求的不断提高,为实时掌握清管器位置,减少人力成本,降低管道堵塞风险,需要实时掌握清管器的位置。本文对光纤传感技术在管道清管器的应用做了详细说明,采用F I R滤波和维纳滤波对系统探测到的振动信号进行增强,对清管器跟踪算法进行了设计和验证。此外,还将现有清管器跟踪技术进行分析和比较。 相似文献
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《Ceramics International》2022,48(21):31299-31308
Aiming at solving the problems of low detection efficiency, poor accuracy rate, and low applicability of the traditional detection methods for surface defects on the silicon nitride (Si3N4) bearing cylindrical rollers. In this study, to detect the surface defects on Si3N4-bearing cylindrical rollers, a nondestructive testing (NDT) method based on an optimized convolutional neural network is proposed, which uses machine vision system to detect the surface defects. The optimized convolutional neural network is a two-stage network. It combines a semantic segmentation sub-network and a decision sub-network. The semantic segmentation sub-network performs an end-to-end learning based on the features of the original image. It completes defect feature extraction to segment the surface defect area from the normal area. The decision sub-network classifies the defects in the segmented surface defect area. The experimental results show that the detection time of surface defects on Si3N4-bearing cylindrical rollers by the proposed network was 72 ms. In addition, its Accuracy (Acc), Percision (Pre), Sensitivity (Sen), and Specificity (Spe) were 97.5%, 99.9%, 99.0%, 98.6%, respectively, which significantly improved the Acc and Pre of the detection of surface defects on Si3N4-bearing cylindrical rollers compared with the traditional detection method. On the other hand, its mIoU, mPA were 84.4%, 92.9%, respectively, meaning brilliant ability of image segmentation for this network. To sum up, the ability of the proposed network to detect and classify surface defects on Si3N4-bearing cylindrical rollers is excellent. 相似文献
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Image segmentation method based on region growing has the advantages of simple segmentation method and complete segmentation target. Because the color discrimination and gray gradient of smoke are not obvious, the traditional region growing segmentation method is difficult to separate it from the image, resulting in an unsatisfactory segmentation effect. To solve this problem, this paper partially improved the region growing method and proposed a new smoke segmentation algorithm based on the improved intelligent seeded region growing (IISRG) method. First, smoke images obtained from experimental videos were converted from the RGB color space to the HSV color space, and image binarization was achieved using background subtraction with an adaptive threshold in the V channel. Then, a pixel in the binary image was selected intelligently as the seed point, which was used for the regional growth. The final smoke segmentation images were obtained by the morphological processing of region growing images. Experimental smoke segmentation results show that the proposed algorithm has a higher overlap rate and a lower overflow rate, and performs a better smoke segmentation effect compared with the other two approaches. In addition, this algorithm can also effectively solve the problems of under‐segmentation and over‐segmentation of smoke images. 相似文献
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基于快速高斯核函数模糊聚类算法的图像分割 总被引:1,自引:0,他引:1
对模糊聚类算法通过引入高斯核函数,平滑图像像素灰度值,从而增强图像分割的抗干扰能力和鲁棒性,并结合阈值模糊聚类算法,提高了图像分割的速度。首先利用阈值模糊聚类法划分初始输入空间,得到模糊规则数及初始聚类中心;然后用高斯核函数平滑图像的像素灰度值;最后用标准模糊聚类算法求解并优化模糊隶属度和聚类中心。将本算法应用于添加噪声的嫦娥一号采集的月球地面灰度图像和Lena灰度图像进行图像分割,仿真结果验证了本方法的鲁棒性、有效性和实用性。 相似文献
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聚乙烯及其复合管道广泛应用于油气输送、城市燃气等能源领域,其安全性至关重要。焊接接头的安全检测及评价是聚乙烯及其复合管道系统安全的关键技术。介绍了聚乙烯管道焊接接头的无损检测原理及方法、冷焊检测技术以及缺陷分类与失效模式三方面内容。对电熔和热熔焊接接头分别采用超声相控阵和耦合聚焦技术进行超声检测,并给出了缺陷剖切与检测结果的对比图。提出了物理概念清晰、工程应用方便的冷焊超声检测方法。将电熔接头中的缺陷分为熔合面缺陷、孔洞、结构畸变和过焊。分别对含不同类型和大小缺陷的电熔接头进行力学性能测试,发现电熔接头存在三种典型的失效模式,即沿电熔套筒壁贯穿裂纹失效、熔合面失效以及沿电阻丝所在平面贯穿裂纹失效。根据试验测试与理论分析结果,提出了相应的安全评定方法。所提出的方法,填补了国内外在聚乙烯管道安全检测与评价方法方面的技术空白,提高了燃气管道的本质安全性。 相似文献
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In the process of designing and analyzing the yarn‐dyed fabric, the yarn color pattern has an important effect on the appearance of the fabric. An automatic color pattern recognition method for yarn‐dyed fabric is proposed in this study. The proposed method uses the fabric images obtained from a high‐resolution digital camera image acquisition system. The local statistical texture features are used for yarn texture segmentation. The yarn color classification problem is then formulated in a research framework of multiregion fuzzy segmentation, which can be added auxiliary variables and solved efficiently by the fast dual projection algorithm. The color values of the yarn crossing points are calculated by the yarn color classification results. The locations of the yarn crossing points are detected by a lightness gradient projection method. Different kinds of fabrics are tested in the experiments. Experiments on 14 actual fabrics show that the approach proposed in this study is effective for classifying yarn color and extracting the yarn color pattern in yarn‐dyed fabric. 相似文献
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使用LabVIEW平台和视觉开发模块完成对相机的标定,选用圆点阵标定板,利用Canny算子提取圆形轮廓,然后基于亚像素边缘提取的圆拟合方法提取特征点在图像坐标系下点中心坐标。该方法降低了摄像机标定的难度,极大地缩短了软件开发周期,具有较高的标定精度,能够满足实际工业检测的精度要求。 相似文献
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在大多数的实际应用中,仅仅将图像分成目标和背景两种类型是远远不够的。然而要实现三类、四类以致多类的分割,就必须研究多阈值的分割方法。以研究Fisher单阈值分割法为基础,利用带有收敛因子的PSO算法将Fisher评价函数来进行两阈值分割,最终推广到多阈值的基于Fisher评价函数的图像分割。并通过定误差图像分割实验证明了方法的有效性,保证了算法的收敛。同时证明了选择一个合适的粒子群规模可以使得带有收敛因子的PSO-Fisher算法在尽量少的迭代次数下提高算法的成功率。 相似文献