轴承端面缺陷自动检测研究

针对微小轴承端面字符与缺陷两者的灰度值相差无几,对缺陷的直接检测造成干扰,提出了基于缺陷周围高亮度特征的检测方法;通过对图像的迭代法阈值分割,定义检测目标的像素数作为缺陷识别的主要依据.结合PLC控制系统,开发的缺陷自动检测程序系统,可实现不合格轴承的在线分拣处理.实验结果表明,系统检测误检率不超过1‰,满足了高精度、高效率检测轴承端面缺陷的要求.     

磁芯表面细小裂纹缺陷自动检测系统的研究

开发了一种基于机器视觉技术针对弧面磁芯细小裂纹缺陷的自动检测系统.该系统包括图像采集与处理系统和运动控制系统.将采集到的图像经过预处理后,运用模板匹配算法对缺陷特征进行比较,从而判断出不合格零件,再通过PLC控制机构删除不合格品.     

甲板宝石轴承外观自动检测的研究

手表甲板宝石轴承由于工艺原因碎裂的概率较大,而且严重影响手表质量。本文采用自动检测技术、CCD光电信号拾取技术和微机实现了对坤表甲板上的宝石轴承裂纹、剥伤、碎裂、划伤等外观的自动检测.由于采用CCD摄象器件对激光照射到宝石轴承上后的衍射光斑进行摄象和信号处理,可分辩出大于0.02mm的细微裂纹;由于采用自动运送、自动检测和自动分组,使检测效率有较大提高。     

轴承环车加工尺寸的自动检测

本文介绍了轴承环车加工尺寸自动检测系统的设计。此系统具有硬件简单，工作可靠，测量精度高等特点。     

轴承套圈端面缺陷在线视觉检测的研究与实现

针对轴承生产企业套圈生产过程中普遍存在端面缺陷的问题与人工目检的现状,提出了基于机器视觉的轴承套圈端面缺陷在线检测方法.首先,对套圈图像预处理后进行边缘检测,采用四连通域定位套圈端面区域;其次,采用最小二乘法拟合端面轮廓以判别外形缺陷,采用极坐标变换将套圈环形端面拉伸成矩形,采用Sauvola局部二值化算法对矩形图进行...     

PLC在微型轴承自动检测系统中的应用

简述了微型轴承自动检测系统的工作原理及其控制要求。介绍了PLC在该装置中如何实现外圆参数检测的控制以及软件设计的流程图。     

基于机器视觉的饰品盒表面质量自动检测系统

针对某工厂以人工方式检测饰品盒表面质量,存在检测效率低、误检及漏检率高等问题,开发了饰品盒表面质量自动检测系统。该系统利用模板匹配方法实现对表面图像的判别,进而根据判别结果来控制系统的设备动作,实现对饰品盒的分类堆放。通过实践检测证明,该系统能够大幅提高产品的检测速度、极大地降低产品的误检率和漏检率,同时也降低了企业的成本。     

沥青混合料自动检测系统研究

以对沥青混合料组成成分进行自动检测与分析为研究目的，运用数字图像处理理论与相关技术对沥青混合料组成成分检测进行系统研究，建立一套可行的识别沥青混合料组成特性的智能检测系统，给出系统软件总体结构设计和主要处理流程框图，并对各模块进行编程调试与脱离环境运行，同时还对该系统的处理结果进行比较分析，给出了适合系统检测研究的模式识别处理方法。采用Delphi编程语言进行应用系统的开发与实现，并对采用该系统检测所得的计算结果进行了误差分析．为沥青混合料的质量评价、提高其性能提供了科学依据。     

基于计算机视觉的织物疵点自动检测的研究方法

织物疵点采用自动检测代替传统的人工检测是纺织品质量控制和管理的重要环节,同时又是纺织自动化的重要标志之一。简要综述了近年来计算机视觉在织物疵点领域的应用和发展情况,着重讨论了自动检测技术近期所涉及的各种方法及其在疵点检测上的应用。开发适合我国的织物疵点自动检测系统,具有深远意义。     

钢球表面缺陷的自动检测与识别

在计算机图像处理理论与模式识别理论的基础上,提出钢球表面缺陷评价方法,给出二窗法确定阈值、噪声去除和轮廓跟踪方法;再从处理后图像中提取能表征缺陷性质的几何特征和纹理特征,以实现计算机对缺陷图像的理解和自动识别。     

Automatic defect inspection for LCDs using singular value decomposition

Thin film transistor liquid crystal displays (TFT-LCDs) have become increasingly popular and dominant as display devices. Surface defects on TFT panels not only cause visual failure, but result in electrical failure and loss of LCD operational functionally. In this paper, we propose a global approach for automatic visual inspection of micro defects on TFT panel surfaces. Since the geometrical structure of a TFT panel surface involves repetitive horizontal and vertical elements, it can be classified as a structural texture in the image. The proposed method does not rely on local features of textures. It is based on a global image reconstruction scheme using the singular value decomposition (SVD). Taking the image as a matrix of pixels, the singular values on the decomposed diagonal matrix represent different degrees of detail in the textured image. By selecting the proper singular values that represent the background texture of the surface and reconstructing the matrix without the selected singular values, we can eliminate periodical, repetitive patterns of the textured image, and preserve the anomalies in the restored image. In the experiments, we have evaluated a variety of micro defects including pinholes, scratches, particles and fingerprints on TFT panel surfaces, and the result reveals that the proposed method is effective for LCD defect inspections.     

精密表面缺陷的数字化检测系统研究

精密表面疵病的自动检测长期以来一直是期待解决的问题。依据显微散射光成像系统对元件表面上的划痕、麻点、气泡等疵病形成暗背景下的亮疵病图像,提出了一个完整的数字化标准的精密表面疵病检测评估体系。首先利用比值匹配原理对xy两方向平移得到的子孔径扫描图像进行拼接。引入数学形态学实现疵病识别。运用膨胀、腐蚀、细化等算法,对二值化图像进行噪声消除,图像分割和特征提取。项目的研究成果已能分辨微米量级的疵病,为建立国内外疵病的数字化标准评价系统提供有力的理论及实验依据。     

微小轴承表面缺陷检测中的自动分拣系统设计

针对微小轴承人工目测效率低、漏检率高等问题,结合微小轴承表面缺陷计算机视觉检测系统控制的总体要求,对分拣系统的组成、可编程控制器（PLC）系统选择、I/O点数确定、PLC与上位机通信进行了研究,设计了基于PLC的软、硬件系统,分拣机构可实现微小轴承的自动输送、翻转及剔除等各种运动。多次实验结果均表明,该分拣系统达到了预期的功能要求,稳定性好,可以应用于实际生产中。     

Automatic surface inspection for directional textures using nonnegative matrix factorization

A global image restoration scheme using nonnegative matrix factorization (NMF) is proposed in this paper. This NMF-based image restoration scheme can be used for inspecting the defects in directional texture surfaces automatically. Decomposing the gray level of image pixels into an ensemble of row vectors, we first reduce the data set from original data space into a lower-dimensional NMF space. The repetitive and periodical primitives are well reconstructed by two lower-dimensional basis and weight matrices with nonnegative elements, named nonnegative matrix approximation (NMA). Then the local defects will be revealed by applying image subtraction between the original image and the NMA. As a consequence, the directional textures are eliminated, and only local defects are preserved if they initially are embedded in the surface. A supervised heuristic, elbow of residual curve rule, is devised which helps users to determine a proper basis space size of a specific image. Experiments on a variety of directional texture surfaces are given to demonstrate the effectiveness and robustness of the proposed method.     

Development of an optical inspection platform for surface defect detection in touch panel glass

An optical inspection platform combining parallel image processing with high resolution opto-mechanical module was developed for defect inspection of touch panel glass. Dark field images were acquired using a 12288-pixel line CCD camera with 3.5 µm per pixel resolution and 12 kHz line rate. Key features of the glass surface were analyzed by parallel image processing on combined CPU and GPU platforms. Defect inspection of touch panel glass, which provided 386 megapixel image data per sample, was completed in roughly 5 seconds. High detection rate of surface scratches on the touch panel glass was realized with minimum defects size of about 10 µm after inspection. The implementation of a custom illumination source significantly improved the scattering efficiency on the surface, therefore enhancing the contrast in the acquired images and overall performance of the inspection system.     

基于图案完整性的高反射曲面缺陷检测新方法

高反射曲面零件的表面缺陷检测是一项具有挑战性的工作,以钢球为例,提出了一种通过识别反射图案的完整性进行表面缺陷检测的新方法.该方法基于钢球表面的反光率极高且达到镜面成像的特性,将钢球置于穹顶形光源内部,光源罩内壁修饰有规则、完整的图案.若钢球表面存在缺陷,则其反射形成的修饰图案的像将在缺陷部分发生扭曲变形或间断缺失.采集钢球表面图像,检测修饰图案所成像的完整性即可实现表面缺陷的检测.设计了内壁修饰同心圆图案的新型光源,利用上述方法,对钢球表面缺陷进行了有效提取与分析,取得了良好效果,验证了该方法对于高反射曲面零件表面缺陷检测的有效性.     

Automatic ultrasonic inspection of large-diameter pipes

A device and a principle of operation of some ultrasound scanners-flaw detectors for diagnosing the basic metal mass of main oil and gas pipelines in reinsulation is considered. Different methods, materials, and devices for efficient excitation and reception of ultrasound waves in pipelines with wall thicknesses of 6–20 mm and the selection of Lamb and Rayleigh wave modes for testing as a function of the pipe-wall thickness are discussed. The principle of operation of a unidirectional primary EMA transducer is described.     

Simplified resubmitted lot inspection from defect counts

Nowadays, as low defect rates per item are often expected in practice, conventional single sampling for lot acceptance purposes is rendered inefficient or unduly expensive. For specific producer’s and consumer’s quality and risk requirements, resubmitted lot sampling usually needs, on the average, less inspection effort than single sampling to properly discriminate between satisfactory and unsatisfactory batches. An integer nonlinear programming problem is stated in order to determine the optimal resubmitted lot sampling plan based on defect count data with limited producer and consumer risks. Nonaccepted lots may be resubmitted for sampling inspection a certain number of times. The number of nonconformities per sampled unit is assumed to follow a Poisson distribution. Quasi-optimal inspection schemes for screening submitted lots of manufactured material are derived in closed-forms by using a normal approximation of the incomplete gamma ratio function. Explicit and quite accurate approximations of the smallest number of units to be tested per lot and the maximum tolerable number of nonconformities in the selected sample are presented. The number of resubmissions with minimal inspection effort and controlled risks is also computed. An application to the manufacturing of glass is provided for illustrative purposes.