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针对医用纱布表面缺陷的特点,研究缺陷检测算法。运用迭代算法对图像进行预处理,有效地去除噪声对图像的影响。采用了一种特殊的图像分割方法即基于数学形态学的分割技术对图像进行边缘检测及分割,保证了边缘检测的连续性,能够分割出完整的缺陷目标图像。利用提取的纱布表面缺陷图像中的形态学特征对缺陷进行分类,实现纱布表面破洞、缺经、断纬等缺陷的识别目的。通过MATLAB软件对一些医用纱布图像进行测试,验证了该方法的可行性和准确率。 相似文献
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当前在对机械加工零件表面缺陷检测时,存在表面缺陷检测精度差的问题,导致检测结果不理想。提出一种基于图像角点匹配的机械加工零件表面缺陷检测方法,利用曲率空间检测零件图像的角点,采用泰勒级数删除伪角点。对特征点邻域梯度方向进行角度限度和就近投影,同时借助双向匹配方法进行机械加工零件图像角点匹配。在上述操作的基础上,利用一维直方图的阈值分割对零件图像进行分割处理,最终实现机械加工零件表面缺陷检测。实验结果表明,该方法能够获取高精度的零件表面缺陷检测结果,且对加工零件缺陷厚度、孔洞缺陷及缺陷最大边界距离的测量均较为准确。 相似文献
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针对笔芯球珠表面缺陷检测识别问题,设计并实现了基于机器视觉的笔芯球珠表面缺陷检测系统。笔芯球珠在球面展开机构作用下,通过图像采集模块获取5张可以完全覆盖整个球面的图像。通过对每幅图像进行缺陷图像提取后,采用基于轮廓角点匹配的方法实现对每幅图像中缺陷图像的拼接;基于提取的有效特征组合通过KNN分类算法对完整的缺陷图像进行缺陷识别。试验结果表明,该方法能够对笔芯球珠表面缺陷进行精确有效的检测与识别。 相似文献
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为解决手机壳表面缺陷检测采用人工目测法,检测效率低且漏检率高的问题,采用基于机器视觉的手机壳表面缺陷检测方法,实现产品缺陷的自动化检测。该检测算法采用八方向的各向异性高斯方向导数滤波器对图像进行卷积滤波,并做归一化处理;利用滤波结果图的直方图确定自适应阈值,并进行阈值分割;对图像进行细化后通过划痕缺陷长度特征进行缺陷的提取。实验结果表明,该划痕缺陷检测算法能够实现长度0.5 mm以上的划痕缺陷的准确检测,检测效率高,满足企业的实际需求。 相似文献
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针对轴承缺陷图像存在的光照不均匀、整体对比度低、缺陷细节模糊等问题,结合鲁棒主成分分析和视觉显著性,提出一种新的轴承表面缺陷检测算法。首先,在鲁棒主成分的基础上,采用广朗日乘子算法计算稀疏矩阵,并根据稀疏矩阵计算缺陷区域的视觉显著值,生成凸显缺陷区域的显著图,然后,利用Otsu法对显著图进行缺陷分割,得到缺陷检测结果。并进行对比实验研究,结果表明,该检测方法能够显著突出轴承表面缺陷区域,实现对轴承表面各类缺陷的有效检测,与其他几种显著性检测方法相比,具有较好的查准率和召回率。 相似文献
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为提高钢球表面缺陷检测的效率和准确性,设计一种基于机器视觉的钢球表面缺陷分拣系统。对钢球表面图像进行图像分割、平滑去噪和二值化预处理,获取钢球表面图像的准确信息,并采用改进的中值滤波算法去除噪声;利用小波变换和多尺度形态学融合算法进行钢球表面缺陷的边缘检测;通过该融合算法和其他算法的检测结果对比和客观数据评价,验证了本文所提算法能够有效保留图像真实细节,并满足钢球分拣系统的需求。 相似文献
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针对光学薄膜制备过程中的表面品质缺陷,给出一种基于机器视觉的多通道同步自动在线检测方案。瑕疵检测精度、薄膜幅宽决定系统须采用多相机同步采样,为此提出一种C/S系统架构处理和管理各通道数据,并采用高性能FPGA设计了多通道同步控制卡。在实验基础上分析了薄膜瑕疵成像特点,提出一种基于误差修正理论的快速瑕疵检测算法,即:无瑕疵的背景图像认为只存在呈正态分布的随机误差,瑕疵看作粗大误差,从而将瑕疵检测问题转化成粗大误差的判别问题。通过连续多次采样求平均的方法得到标准背景图像,算出每个像素坐标位置的标准差σ,然后对每幅待检图像应用3-σ准则进行瑕疵判别,可直接得到二值化的瑕疵分离结果。实验结果表明,该算法具有简单、快速、准确的优点,解决了普通差影算法阈值确定困难的问题。 相似文献
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Using recent papers on scanning electron microscopy (SEM) of chemical vapor deposition (CVD) diamond films, two analytical applications of the SEM are discussed: the morphologic investigations (secondary electron emission mode) and the recognition of impurities and defects [cathodoluminescence (CL) mode]. Studies of CVD diamond films by SEM demonstrate that the morphologies of these films are affected by synthesis conditions, especially by substrate temperature, methane concentration, and total pressure in the reactor. CL spectra and images are useful tools for clarifying the relationship between emission centers and different types of defects generated during the process of diamond crystal growth. The paper shows that the investigations of the morphology, crystallinity, local CL emission, as well as the surface distribution of CL spectra on CVD diamond films by SEM led to the correlative information for quality estimation of films in comparison with natural diamond. 相似文献
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Yue-Rong Li Gavin Pereira Andreas Lachenwitzer Masoud Kasrai Peter R. Norton 《Tribology Letters》2008,29(1):11-22
X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of thermal films on
steel samples, which were generated from a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive. These
films were formed at 150 °C by immersing steel coupons in ZDDP oil solutions. The phosphorus L-edge XANES spectra show that
these films are composed of polyphosphates, unreacted ZDDP and other thiophosphate intermediates. Phosphorus K-edge FY XANES
was used to monitor the thickness of these films, and the data are consistent with thickness derived by focussed ion beam
(FIB) milling and SEM imaging. The sulphur K-edge TEY and FY XANES spectra show that these films are composed of different
sulphur components, which depend upon the formation times. The surface morphology of these films was investigated using atomic
force microscopy (AFM). These images show that the surface morphology of the thermal films changes with the formation time.
31P NMR spectra show that both primary and secondary ZDDP decomposes gradually at 150 °C. 相似文献
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基于多幅X射线数字图像的缺陷自动识别技术 总被引:4,自引:0,他引:4
在现有的X射线数字图像自动识别方法中,多采用对单幅数字图像进行孤立评判的方法。由于此类方法中阈值选取难以最优化,因而存在一定的误判率。为了解决这一问题,提出了一种X射线数字图像自动识别新方法。该方法将识别过程分为两步:缺陷提取和缺陷跟踪。第一步利用传统方法在每幅图像中分离出潜在缺陷。这一步保证真缺陷能全部提取出来,而不考虑伪缺陷的数量。第二步力图找出同一试件不同图像中分离出的缺陷之间的相互关系。如果第一步某一图像中分离出的某一缺陷在其他图像中都找不到相对应的缺陷区域,就定义该缺陷为伪缺陷,也就是说,真缺陷在不同图像中必须满足一定的几何关系。多幅图像中的缺陷跟踪综合利用了极线约束、三维重建和三线性约束等立体视觉算法。该方法的检测效果已经利用航空发动机叶片X射线数字图像得到验证。试验结果表明:利用该方法可以提高真缺陷的识别率,降低误判率。 相似文献
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Sub-monomolecular layers of a derivatized Phthalocyaninato-poly-siloxane (PCPS) and a Polydiacetylene (PDA) have been prepared on highly orientated pyrolytic graphite and gold by Langmuir-Blodgett and Langmuir-Schäfer techniques. Raman scattering and grazing-incidence-reflection infrared spectroscopy were used to characterize packing and molecular orientations within these films. It was found that PCPS forms similarly well ordered monolayers on both graphite and gold while PDA does not. Scanning tunnelling microscopy (STM) was performed in air using both the constant height and constant current mode. On highly orientated pyrolytic graphite substrates various defect structures based on a √3X√3 R 30° superstructure were found near localized defects and small graphite steps. They were carefully distinguished from molecular images of densely packed hydrocarbon chains. Defect rich graphite was characterized with both STM and Raman spectroscopy. Similarly, disordered and graphite-like regions were found on carbon fibres. The sensitivity of STM to surface defects in graphitic material turned out to be large compared to that of the Raman spectroscopic method. STM images of PCPS monolayers on graphite and gold exhibited parallel polymer rods, 2 nm apart from each other. 相似文献
15.
Dmitriev Y Bennett PR Cirignano LJ Klugerman M Shah KS 《The Review of scientific instruments》2007,78(5):053907
An experimental method for determining the range of alpha particles in films based on I-V(s) analysis has been suggested. The range of 5.5 MeV alpha particles in PbI(2) films determined by this technique is 30+/-5 microm, and this value is in agreement with the value calculated by SRIM (the stopping and range of ions in matter), r=24 microm in PbI(2). More than 100 I-V(s) of PbI(2) films with different thicknesses and quality have been analyzed, and the influence of alpha particle radiation on PbI(2) I-V(s) curves has been studied. Developed analytical methods (dependence of current density on electric field and conception of surface defects) were used, and the method limitations are discussed. It was shown that I-V(s) demonstrate the tendency to obey Ohm's law under alpha radiation. On the other hand, dark conductivity of the lead iodide films shows a typical impure character that can lead to an overestimation of the alpha particles' range in PbI(2) films. After films were exposed to alpha radiation, the dark resistivity and I-V shape of some films improved. Also, a weak decrease of the charge carrier concentration, due to a decrease of the "surface defect" concentration ("surface refining"), was registered after successive measurements of I-V(s). 相似文献
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Yuh-Ping Chang 《Wear》2009,266(11-12):1119-1127
The novel method of using continuous tribo-electrification variations to monitor the dynamic tribological properties between metal films has been applied successfully [Y.P. Chang, A novel method of using continuous tribo-electrification variations for monitoring the tribological properties between the pure metal films, Wear, 262 (2007) 411–423]. The method was shown to produce clear and strong signals, superior to monitoring continuous friction coefficient variations. However, the above method was only shown to be suitable for the tested material pairs that were studied. In this paper, the method was improved and applied to monitoring the dynamic tribological properties between titanium oxide (TiO2) films in the friction process. The experiment was conducted on a purposed-designed friction tester with a suitable measuring system. In order to investigate the tribological property of titanium (Ti) sliding against Ti with TiO2 films in detail, the continuous variations of electrical contact resistance and friction coefficient were measured for monitoring the onset of film rupture between the TiO2 films and the chemical reactions between the interfaces. Wear loss was measured by an accuracy balance and scan electron microscopy was used to observe the microstructures and material transfer. The experiments demonstrated that the novel method of using electrical contact resistance variations has great potential for monitoring the dynamic tribological properties and the chemical reactions of titanium specimens. 相似文献
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Shrestha Ranjit Manyong Choi Wontae Kim 《Journal of Mechanical Science and Technology》2016,30(3):1111-1118
The increasing use of composite materials in various industries has evidenced the need for development of more effective nondestructive evaluation methodologies in order to reduce rejected parts and to optimize production cost. Infrared thermography is a noncontact, fast and reliable non-destructive evaluation technique that has received vast and growing attention for diagnostic and monitoring in the recent years. This paper describes the quantitative analysis of artificial defects in Glass fiber reinforced plastic plate by using Lockin infrared thermography. The experimental analysis was performed at several excitation frequencies to investigate the sample ranging from 2.946 Hz down to 0.019 Hz and the effects of each excitation frequency on defect detachability. The four point method was used in post processing of every pixel of thermal images using the MATLAB programming language. The relationship between the phase contrast with defects depth and area was examined. Finally, phase contrast method was used to calculate the defects depth considering the thermal diffusivity of the material being inspected and the excitation frequency for which the defect becomes visible. The obtained results demonstrated the effectiveness of Lock-in infrared thermography as a powerful measurement technique for the inspection of Glass fiber reinforced plastic structures. 相似文献
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Yue-Rong Li Gavin Pereira Andreas Lachenwitzer Masoud Kasrai Peter R. Norton 《Tribology Letters》2007,27(3):245-253
X-ray absorption near-edge structure (XANES) spectroscopy has been used to characterize the chemistry of antiwear (AW) films
generated from mineral base oil containing a zinc dialkyl dithiophosphate additive. These films were formed on rubbed steel
surfaces with a reciprocating boundary contact using different sliding frequencies. The phosphorus L-edge XANES spectra show
that these films have slightly different chemical natures. Longer chain polyphosphates were present on the steel surface prepared
at the higher sliding frequencies. The surface morphology of these films was investigated using atomic force microscopy. These
images show that the surface morphology of the AW films changes with the sliding frequency. Round and bigger antiwear pads
were formed at a lower frequency while higher frequencies resulted in thinner films and flattened surfaces. Nanomechanical
properties of these antiwear films were investigated by nanoindentation measurement and the elastic moduli extracted from
force–displacement (f–d) curves are similar for all antiwear films, 100 ± 10 GPa. 相似文献
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Radiographic images segmentation is the major interest for the weld defect diagnosis and monitoring in the field of industry. In this work we present a method that takes ownership of local segmentation geodesic active contours. The goal of the method presented in this paper is to automate the process of extracting dimension of weld defects from radiographic images using level set segmentation. The information would be used in the area of nondestructive testing (NDT). This method is found to be effective and robust. 相似文献