基于机器视觉的BGA连接器焊球检测

文章提出了一种基于机器视觉的BGA器件焊球质量检测方法。该方法在同一视点下,用相同光源分别以两种不同入射方向角照射被测BGA连接器焊球,获得两幅图像,然后得到BGA连接器焊球在x方向的曲面信息,以此计算出被测焊球的主要质量参数。最后给出了BGA连接器焊球检测的主要算法。     

基于点模式匹配的BGA芯片视觉检测与定位算法及其实现

点模式匹配是视觉测量中的一种新方法;针对贴片机生产中BGA芯片的图像识别对中问题,系统地介绍了BGA的视觉检测任务,提出了基于点模式匹配的快速定位算法;该算法针对BGA焊球分布特点,对传统点模式匹配算法进行优化,大大减少了运算量;现场实际运行结果表明该算法的速度和精度都能满足实际生产的需要,并具有较强的鲁棒性。     

BGA焊点气孔缺陷的特殊结构光质量检测

为了解决球栅阵列（BGA）焊点气孔缺陷的在线检测问题,开发了一种特殊的结构光检测技术。同时用环形红光和十字形绿光发射二极管（LED）照明BGA芯片,通过环形和十字形的中心,布置一个带有远心透镜的电荷耦合器（CCD）摄像机记录小球上红色圆环和绿色十字的图像。根据图像半径方向上的纹理频谱分布特征,引入人工神经网络（ANN）算法对BGA芯片的气孔缺陷进行检测。采用真实的BGA焊点进行实验,结果验证了方法的精度和可行性。     

基于图像处理的BGA封装器件缺陷检测算法

提出了一种BGA焊球缺陷检测算法 ,通过图像处理技术 ,检测BGA器件各焊球的中心位置、焊点直径、各行列坐标等参数 ,以检测是否发生焊球丢失、移位、焊球过大或过小以及桥连等缺陷 ,从而保证BGA器件的质量。     

机器视觉在线检测图像处理技术研究

传统在线检测处理技术一般是指通过人类肉眼进行检测处理,工作强度大,检测精准度低,已经无法满足高科技环境对图像检测提出的要求。基于机器视觉的角度对图像进行在线检测是一种最新技术,这种技术对图像的处理过程更加快速,处理结果更加精准,处理方法更加多种多样。对机器视觉在线检测图像处理技术进行全方位系统性地研究,阐述了机器视觉在线检测图像处理技术的主要内容,分析了处理方法,与传统技术进行了对比实验。通过本文的研究可以了解到机器视觉在线图像处理技术处理能力极强,稳定性极高,是未来对于图像进行检测处理的必然发展方向。     

在线检测产品疵点系统的DSP实现

为了提高出厂产品的质量,需要在生产线上对产品进行高速在线检测,该文采用基于机器视觉的检测系统来进行在线检测产品疵点。该系统采用类别共生矩阵算法建立纹理模型,采用CCD视觉传感、高速DSP芯片、USB数据传送等技术结合软件算法构成高速在线机器视觉检测系统。     

基于机器视觉的芯片成型分离视觉检测系统的研究

芯片引脚是否合格,是成型分离制程检测的关键。针对这一问题,应用机器视觉和机器自动化技术,研制出实现成型分离制程芯片检测自动化的检测系统。实验测试表明,该设备具有较高的检测精度和检测速度,能够满足生产需要。     

结合全卷积网络和K均值聚类的球栅阵列焊球边缘气泡分割

针对在球栅阵列（BGA）气泡检测中,由于图像干扰因素的多样性导致焊球存在边缘气泡与背景之间灰度级接近,从而造成焊球气泡分割结果不精确的问题,提出了一种结合全卷积神经网络（FCN）和K均值（K-means）聚类分割的焊球气泡分割方法。首先根据所制作的BGA标签数据集搭建FCN,通过训练该网络得到合适的网络模型,再对待测BGA图像进行预测处理得到图像的粗分割结果;然后对焊球区域映射提取,通过同态滤波法提高气泡区域辨识度,再使用K-means聚类分割对图像进行细分割处理,得到最终分割结果图;最后对原图焊球及气泡区域进行标注识别。将所提出的算法与传统BGA气泡分割算法进行对比,实验结果表明,所提出的算法对复杂BGA焊球的边缘气泡分割精确,图像分割结果与其真实轮廓高度匹配,准确度更高。     

基于5G和工业操作系统在芯片封装领域的机器视觉检测应用

1 背景 集成电路芯片已广泛应用于多个领域,但是制造过程中产生的缺陷会直接影响集成电路芯片的寿命和可靠性.传统的人工检测方法,存在耗时长、劳动强度大、误检率高等缺点,已无法适应生产的需求.通过机器视觉检测技术对产品进行分析处理,检验产品是否符合质量要求,对保障产品质量,提高产品合格率起到了关键作用.     

机器视觉工业检测系统的应用与发展

介绍了机器视觉工业检测系统的发展概况,阐述了机器视觉的研究已经从实验室走向实际应用的发展阶段,业已成为当代计算机技术研究的热点,获得了广泛的工业应用。重点讨论了机器视觉系统在实际工业生产中的应用及工业视觉检测原理、常用图像处理算法等。举例说明了如何利用模板匹配法对目标图像进行识别,从而实现对产品包装的检测。最后,指出在社会高度信息化发展过程中,在人类获取信息中占很大比例的视觉信息处理技术及机器视觉测量系统,将受到人们越来越多的关注。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).