共查询到20条相似文献,搜索用时 125 毫秒
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针对高精度自动贴片机的视觉系统图像预处理算法进行了研究,提出了针对贴片机PCB板标记点及元件图像处理的预处理方法.开发了针对视觉定位系统的图像识别软件,并用PCB板图像及元件图像进行实验验证.实验结果表明,该预处理算法能够有效地分割原始图像目标区及背景区、排除干扰噪声、增强图像特征,为贴片机进一步的图像识别及定位提供了有利条件. 相似文献
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基于数字图像处理的印刷电路板缺陷检测 总被引:2,自引:0,他引:2
针对传统PCB检测方法高成本、低效率问题,提出一种基于数字图像处理的PCB板自动光学检测方法,建立了将标准图像和待测图像进行对比的检测系统。针对PCB板生产过程中遇到的短路、断路、空洞、凸起、凹陷等缺陷,采用了求连通区域数、计算欧拉数、求缺陷区域面积等方法,来检测上述缺陷问题,并给出算法的全过程。经实验结果分析,该方法能准确地检测出待检测电路板上存在的缺陷,达到了自动实时检测的目的。 相似文献
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快速精准地识别PCB板上感兴趣区域的位置,是图像处理过程中衡量算法有效性的重要指标。在图像处理的前期,通过分析同一背景条件下灰度曲线的变化趋势,确定光照不均匀对于PCB板感兴趣区域的影响,提出了运用同态滤波处理降低图像灰度变化的动态范围,从而加强感兴趣区域中目标和背景的对比度。基于现阶段相关PCB板的识别分割算法,针对研究对象PCB板实际感兴趣区域的灰度分布,探讨了全局阈值分割方法的优势。在此基础上,为了更精确的图像分割效果,提出了一种基于灰度直方图数据拟合的阈值分割方法。根据不同的阈值分割算法对图像进行处理,通过比较分析,结果表明本文提出的算法能够更加快速精确地分割出图像的感兴趣区域。 相似文献
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为了能快速、准确地对BGA封装器件的PCB板上的焊点进行缺陷检测,设计了高分辨率X-射线无损检测的缺陷检测系统.给出了系统的基本工作原理和硬件结构,采用等比例成像的方法求解了获得最高分辨率的距离信息.分析了系统可能存在的噪声源,并设计了去噪算法用于提高图像信噪比.试验采用HAWK-180XI型X-射线源、高速图像采集卡和UNIQ-2000型CCD相机等对BGA封装的PCB板缺陷进行检测,结果显示:系统可以快速有效地获得被测PCB板的图像信息,并给出缺陷的位置、尺寸等特征信息,满足设计要求. 相似文献
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Dr L. P. Khoo N. S. Ong 《The International Journal of Advanced Manufacturing Technology》1998,14(5):363-368
Printed circuit boards (PCB) are used extensively in industry for the manufacture of electronic and electromechanical products. One of the primary concerns in the manufacture of PCBs is the determination of the optimal assembly plan. This paper presents work that leads to the development of an approach to PCB assembly planning using genetic algorithms (GAs). The approach takes into consideration component insertion priority and sequencing decision rules. A polygamy reproduction mechanism with dual mutation has been proposed and implemented. Details of the approach are described. A PCB model extracted from the literature was used for performance evaluation. Details of the evaluation are presented. 相似文献
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基于改进的SIFT特征的图像双向匹配算法 总被引:2,自引:0,他引:2
图像匹配是计算机视觉中许多领域的基础,特征提取则是图像匹配的基础,其中不变量特征是一个重要的理论。SIFT是最有效的尺度、旋转、亮度不变量局部特征之一,但算法复杂、计算时间长。分析了SIFT的计算时间分配,通过计算关键点的邻域梯度直方图时动态修改采样步长,大大提高了SIFT的计算速度。分析了基于SIFT特征的图像匹配算法,提出了双向匹配算法,提高了图像匹配的准确率。实验结果表明所提出的方法是有效的。 相似文献
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针对传统局部不变特征的景象匹配算法冗余点多、实时性差、抗几何变换不突出的情况,提出基于CenSurE-star的无人机(UAV)景象匹配算法。首先采用Cen Sur E特征星型滤波器(CenSurE-star)提取基准图和实时图中的特征点,并生成FREAK二进制描述符;然后将汉明距离作为特征点的相似性判定度量,采用K近邻距离比值的方法提取匹配点对;最后利用基于RANSAC的定位模型得到空间几何变换关系,实现图像匹配并获取定位点经纬坐标。算法性能评价实验表明,本文算法不仅相对于SIFT、SURF、ORB算法,对各种变换具有更好的鲁棒性,而且相对于改进的SIFT、SURF算法处理时间有更大程度的缩短,算法定位误差在0.8个像素内,尺度误差在0.02倍内,旋转角度误差在0.04°内。基于算法进行外场飞行实验,实验证明算法定位精度较高,可以适应地貌信息较少的环境,并能满足无人机视觉辅助导航的需求。 相似文献
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William Ho Ping Ji Prasanta Kumar Dey 《The International Journal of Advanced Manufacturing Technology》2008,37(7-8):828-836
This paper presents two hybrid genetic algorithms (HGAs) to optimize the component placement operation for the collect-and-place
machines in printed circuit board (PCB) assembly. The component placement problem is to optimize (i) the assignment of components
to a movable revolver head or assembly tour, (ii) the sequence of component placements on a stationary PCB in each tour, and
(iii) the arrangement of component types to stationary feeders simultaneously. The objective of the problem is to minimize
the total traveling time spent by the revolver head for assembling all components on the PCB. The major difference between
the HGAs is that the initial solutions are generated randomly in HGA1. The Clarke and Wright saving method, the nearest neighbor
heuristic, and the neighborhood frequency heuristic are incorporated into HGA2 for the initialization procedure. A computational
study is carried out to compare the algorithms with different population sizes. It is proved that the performance of HGA2
is superior to HGA1 in terms of the total assembly time. 相似文献
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0 lNTRODUCTlONWith the rapid development of assembleautomatic,machine visinn has been poPularly used onsudsce mounted technofogy (SMT ) field. It hasreSOved many problems in electronic factory assemblyline environments. Ref. [ l ] -- Ref. [ 41 gave someexamples, which resolved many insPeCtion prOblems inSMT from the views of image process and imageaedysis, image defect clinic strategy and somecommerce vision system. Teday, the machine visionbranch system is used in almost all of the h… 相似文献
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针对传统图像匹配算法存在的计算量大、匹配速度缓慢的缺点,对基于相关函数法的投影法进行了改进,提出了一种基于投影特征的自适应图像匹配算法。得到投影序列后,选定初始阈值,在后续各点的计算中不断自适应更新,遵循超过当前阈值即停止匹配计算的原则,大大减少了对非匹配点的计算。实验结果表明,该算法抗干扰性强,匹配速度快;模板图像和待匹配图像大小越接近,该算法精度越高,速度优势越明显。 相似文献
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基于色彩分割和自适应窗口的快速立体匹配 总被引:3,自引:1,他引:2
针对现有立体匹配算法难以兼顾匹配精度和速度的不足,提出了一种基于联合匹配代价的局部方法.首先,根据视差在同一色彩分割区域内平滑变化的假设,提出了一种利用参考图像和目标图像的色彩分割信息获得的基于任意形状和大小支持区域的匹配代价;然后在RGB色彩空间中,通过由窗口内的平均匹配误差、误差方差及较大窗口的偏向误差构成的窗口选择评价函数,获得基于自适应矩形窗口的匹配代价;最后,将这两种匹配代价进行有机的结合构成联合匹配代价,并通过局部优化方法获得稠密视差图.采用Middlebury dataset进行的实验结果表明,本文算法不仅可以提高视差不连续区域和低纹理区域的匹配精度,而且获得的视差与当前主流算法具有可比性.此外,所提算法的处理时间较之当前优秀的局部方法提高了约19~35倍. 相似文献
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C.-H. Yeh 《The International Journal of Advanced Manufacturing Technology》2003,21(3):223-233
This paper presents a novel approach for localising open and short boundary defect candidates on ball grid array (BGA) substrate
conducting paths by using a 2D wavelet transform (2D WT). Once the potential defects are identified, traditional printed circuit
board (PCB) inspection algorithms can focus on these candidates for further analysis to identify true open and short defects.
The defect-detecting scope and the inspection effort are thereby significantly reduced. The binary BGA substrate image is
processed. It shows only the boundaries of BGA substrate conducting paths, which are further decomposed directly by 2D WT.
Since most of the wavelet energy is clustered at the edges of image objects, the wavelet transform modulus sum (WTMS) of each
edge pixel on BGA substrate conducting path boundaries is initially collected. By comparing the WTMS of an edge pixel on decomposition
level j with its WTMS on an adjacent decomposition level j + 1, an across-level ratio can be estimated to verify the irregularity of an edge pixel. That is, an edge pixel is classified
as strongly irregular (e.g. potential open or short defects) if its across-level ratio reaches a predefined threshold. The
proposed approach is template-free and easy to implement, so it is suitable for small-batch production. Real BGA substrates
with synthetic boundary defects are used as test samples to evaluate the performance of the proposed approach. Experimental
results show that the proposed method is capable of capturing all the open and short defects on BGA substrate conducting paths
without missing any errors by using a selected across-level ratio threshold and appropriate decomposition level. 相似文献