AOI技术在PCB缺陷检测中的设计与实现

随着计算机技术和数字图像处理技术的快速发展,传统PCB缺陷检测技术因技术落后已经无法满足现代PCB质量的要求,而AOI技术以其准确、高效的特点在PCB缺陷检测中的应用越来越受到重视.主要研究了AOI技术在PCB缺陷检测中的实际应用,分别进行了硬件选择和软件系统研究,建立了基于AOI技术的PCB缺陷检测系统,采用基于轮廓对比的数据处理方法进行缺陷检测.实验证明了该系统的可行性与实用性.     

大师答疑Q＆A

电视卡有两个音频输出接口：挡板的Audio Out和PCB板的四针接口。用光驱音频线将PCB四针接口与声卡CD-ln接口相连，效果和电视卡Audio Out接口连接声卡Line-ln接口几乎相同，请问两种方式有何不同，哪种声效更好?     

贴片机设备中CAD-CAM数据接口的设计和实现

本文设计了一种CAD-CAM数据接口，用于实现贴片机贴装数据的自动提取和转换。该CAD—CAM数据接口以Protel PCB文件为源文件，通过分析PCB文件中元件信息的数据结构和数据格式，从中提取和转换得到贴片机所需的生产数据。实践证明该方法极大提高了贴片机的生产效率。     

基于树莓派和YOLOv5的PCB瑕疵检测

针对PCB瑕疵检测问题，提出了基于YOLOv5s的轻量化PCB瑕疵检测算法，并基于树莓派平台搭建了一套PCB瑕疵自动检测系统。首先，在Backbone阶段使用改进的空间金字塔池化代替原有的C3网络；其次，在Backbone与Neck中引入残差结构，并在小目标检测层面加入CBAM注意力机制；最后，将所提轻量化算法部署到树莓派上，并使用NCS2套件进行辅助加速，通过摄像头进行自动检测。通过测试，所提算法检测PCB瑕疵mAP达到99.1%,与原YOLOv5s模型相比，Params为其23%,FLOPs为其21%,PCB瑕疵检测系统运行速度达到7 fps,满足自动检测要求。     

Registered SDRAM在 MPC8241系统中的应用

介绍Registered SDRAM的工作原理和接口芯片，以及在MPC8241嵌入式系统中进行Registered SDRAM电路设计的实例；给出电路原理设计和PCB布局布线的一般规则。     

基于人工智能的PCB缺陷检测系统

PCB缺陷检测在现代电子信息技术中越来越重要,因此提高检测的效率和准确性是亟需研究的一个问题。针对这一问题,设计了一套基于人工智能识别的PCB故障智能检测系统。该系统首先利用硬件系统采集图像,再通过软件系统完成灰度化、中值滤波等图像预处理操作。之后利用Canny算子和霍夫变换获取边缘信息,并分割元器件图像。最后,利用事先训练好的神经网络模型实现故障识别。实际测试表明,该检测系统的准确率大于90%,因此该系统在PCB质量检测领域具有实际应用的意义。     

HTPC产品推荐

希捷Barracuda Green2TB硬盘采用3碟片6磁头设计，单碟容量为667GB。该硬盘采用了最新的SATA 6Gb／s接口，显著提升了接口的数据传输率，缓存容量也达到了64MB。Barracuda Green相对于Barracuda LP的PCB缩小了，宽度不到3英寸，反转设计的PCB使得芯片等元件置于内部，避免磕碰和沾染灰尘，能延长产品使用寿命。     

LED显示屏硬件控制系统设计

详细介绍LED显示屏的硬件系统设计,分别对DVI接口模块、千兆以太网接口模块、SDRAM模块、硬件设计单片机系统及配置模块、FPGA模块及JTAG接口和电源模块等予以分析,得出PCB制作电路图。     

基于PCI总线的超大规模集成电路边界扫描测试系统

采用现场可编程门阵列（FPGA）和PCI9052目标接口芯片，实现了符合PCI总线规范和IEEE1149．1标准的超大规模集成电路边界扫描测试系统，具有对系统级、PCB级和芯片级集成电路进行边界扫描测试的功能，结构简单、速度快、工作可靠。     

抑制△I噪声的PCB设计方法

数字系统中的△I噪声是一个重要而复杂的问题。随着数字系统向大规模、高集成度、高速度、低工作电压等方向发展，△I噪声已逐步成为PCB电磁辐射的主要来源，并成为影响系统EMC的重要因素之一。虽然抑制△I噪声一般需要从多方面着手，但通过PCB设计抑制△I噪声是有效的措施之一。如何通过PCB设计抑制△I噪声是一个亟待深入研究的问题。在对△I噪声的产生、特点、主要危害等研究的基础上，讨论了辐射干扰机理，重点结合PCB和EMC研究的新进展，研究了抑制△I噪声的PCB设计方法。对通过PCB设计抑制△I噪声的研究与应用具有指导作用。     

Pywinauto在Windows Twain Driver自动化测试中的应用研究

以Python为基础,结合对Twain Driver测试工具的具体需求,将Pywinauto引入到Twain Driver的自动化测试中。介绍了Pywinauto的基本概念,通过测试用例说明Pywinauto在自动化测试中的具体实现。应用结果表明,该方法大大提高了测试的自动化程度,极大地减少了Twain Driver测试的工作量,同时也确保了测试质量。     

用VC设计数码相机、扫描仪和图像采集程序

TWAIN技术规范定义了图像采集硬件与应用软件之间的通讯协议和编程接口标准。文章在解释该技术规范的基础上，介绍如何用visual c^ 来设计数码相机和扫描仪的图像采用程序。     

Optimal inspection interval for a k-out-of-n system with non-identical components

In this paper, we develop a continuous-time discrete-state model for periodic inspection of a k-out-of-n cold-standby system with non-identical components. A perfect switching system detects the components’ failures, and the failed component(s) are repaired during the next inspection interval, and then added to the standby queue. The system can be in different states depending on the combination of working components and the order of the components on the standby queue at the beginning of an inspection interval. We present a matrix-based approach to determine the system states and calculate the system-states transition probabilities and the transition matrix. We calculate the expected total cost of the inspection intervals by determining the system state at the beginning and end of each inspection interval and calculating the inspection cost matrix. The expected total inspection cost consists of the system downtime cost, components repair cost, system repair cost, and system inspection costs. Finally, we minimize the system’s expected total cost by determining the system’s optimal inspection interval. The results show that determining the optimal inspection interval decreases the system's total inspection interval cost up to 60 % in comparison with the cases when the inspection interval is selected arbitrarily.     

Evaluation of best system performance: Human,automated, and hybrid inspection systems

Recently, 100% inspection with automated systems has seen more frequent application than traditional sampling inspection with human inspectors. Nevertheless, humans still outperform machines in most attribute inspection tasks. Because neither humans nor automation can achieve superior inspection system performance, hybrid inspection systems where humans work cooperatively with machines merit study. In response to this situation, this research was conducted to evaluate three of the following different inspection systems: (1) a human inspection system, (2) a computer search/human decision‐making inspection system, and (3) a human/computer share search/decision‐making inspection system. Results from this study showed that the human/computer share search/decision‐making system achieve the best system performance, suggesting that both should be used in the inspection tasks rather than either alone. Furthermore, this study looked at the interaction between human inspectors and computers, specifically the effect of system response bias on inspection quality performance. These results revealed that the risky system was the best in terms of accuracy measures. Although this study demonstrated how recent advances in computer technology have modified previously prescribed notions about function allocation alternatives in a hybrid inspection environment, the adaptability of humans was again demonstrated, indicating that they will continue to play a vital role in future hybrid systems. © 2003 Wiley Periodicals, Inc. Hum Factors Man 13: 137–152, 2003.     

基于计算机视觉的海产品抗生素残留检验方法

针对海产品抗生素残留传统检验方法存在劳动强度大、重复性高的问题,研究并建立了基于计算机视觉的抗生素残留自动检验系统,该系统包含抑菌圈图像的自适应降噪和背景校正、多分辨率的二次抑菌圈检测拟合、以及符合国家标准的抗生素残留计算方法.以海产品中四环素族抗生素残留检测进行的试验表明,本文研究的方法具有速度快、精度高、操作简便等优点,开发的系统能够满足部分抗生素残留的检测需要.理论分析和试验证明了该系统的优点和有效性.     

Nondestructive evaluation sensor fusion with autonomous robotic system for civil infrastructure inspection

Civil infrastructure inspection is crucial to maintaining the quality of that infrastructure, which has a great impact on the economy. Performing this inspection is costly work that requires workers to be trained on how to use varying technologies, which can be error prone when performed manually and can result in damage to the infrastructure in some cases. For this reason, nondestructive evaluation (NDE) sensors are preferred for civil infrastructure inspection as they can perform the necessary inspection without damaging the infrastructure. In this paper, we develop a fully autonomous robotic system capable of real‐time data collection and quasi‐real‐time data processing. The robotic system is equipped with several NDE sensors that allow for a sensor fusion method to be developed that successfully minimizes inspection time while performing adequate inspection of areas that require more in‐depth data to be collected. A detailed discussion of the inspection framework developed for this robotic system, and the dual navigation modes for both indoor and outdoor autonomous navigation is presented. The developed robotic system is deployed to inspect several infrastructures (e.g., parking garages, bridges) at and near by the University of Nevada, Reno campus.     

A simplified visual inspection system using a personal computer

For a practical visual inspection system, data processing in real time, flexibility for variety of products, and cost performance have been required. This article describes a simplified visual inspection system that has well-balanced performance that meets these requirements. Inspection data processing by software makes the inspection system flexible. Development of a simplified pattern matching method based on limiting the inspection within the area pointed by an user and direct memory access of binary image data performs a high speed inspection function. By using a personal computer as a processor of this system, a cost effective inspection system is realized.     

Evaluation of a job‐aiding tool in inspection systems

Visual inspection plays a very important role in ensuring quality in the manufacturing and service industries. Two determinants of inspection performance are visual search and decision‐making. Improvement in any one of the components will have an impact on system performance. Job‐aids, accompanied by training, have proven to be effective in enhancing accuracy and reducing search time in visual inspection systems. This article aims to investigate the effects of search strategy along with task complexity and pacing on inspection performance using a job‐aiding tool. To facilitate the experiments, an enhanced job‐aiding tool in a simulated visual inspection environment was developed. This tool enables an inspector to track his or her search path in visual inspection systems. A pilot study and two experiments were conducted using this tool. The pilot study examined the effectiveness of the job‐aiding tool. The first experiment studied the effect of search strategy and task complexity on inspection system performance and the second experiment studied the impact of search strategy, task complexity, and pacing on system performance. Results from this research can be used to better design an inspection system. © 2007 Wiley Periodicals, Inc.     

基于VI的面向质量检测的虚拟测试系统

基于虚拟仪器的虚拟测试技术在先进制造系统质量检测及质量控制中具有广泛的应用前景。探讨了先进制造系统质量检测中虚拟测试和虚拟仪器的应用特点，提出了采用面向对象技术的面向质量检测的虚拟测试系统的体系结构及虚拟测试应用软件模型。面向质量检测的虚拟测试系统的建立，为质量检测，计算机辅助质量系统（CAQ）以及质量控制和质量保证提供了新途径。     

RFID技术在电梯检验系统中的应用

目前电梯检验效率低下,有必要利用计算机、通信等技术开发电梯检验辅助系统,提高检验效率。提出了在电梯检验系统中应用射频识别技术(RFID)来解决电梯身份识别难的设计构想,分析了电梯检验系统的总体架构和系统中RFID模块的构成,给出了RFID模块的软硬件设计。与传统的检验方法相比,RFID技术的应用能提高电梯检验工作的效率和质量,实现电梯身份识别的数字化和智能化。