Automated visual inspection: a survey

This paper surveys publications, reports, and articles dealing with automated visual inspection for industry. The references are organized according to their contents: overview and discussions, rationales, components and design considerations, commercially available systems, applications. A number of applications and their inspection methodologies are discussed in detail: the inspection of printed circuit boards, photomasks, integrated circuit chips. Other inspection applications are listed as a bibliography. A list of selectively annotated references in commercially available visual inspection tools is also included.     

Automated visual inspection: A tutorial

This article introduces the topic of automated visual inspection (AVI) as a subset of machine vision. The components of a generic AVI system will be presented and current applications of AVI systems will be discussed. Specifically, the applications of automated dimension verification, bare printed circuit board inspection, stuffed printed circuit board inspection and component identification using color technology will be covered in some detail.     

Automatic inspection system for printed circuit boards

The purpose of this correspondence is to present problems and methods in automating visual inspection of printed circuit boards (PCB's). Vertical and diagonal illumination are useful in detecting PCB patterns correctly. An algorithm comparing local features of the patterns to be inspected with those of the pattern to be referenced is proposed. An inspection system using developed technologies is also described.     

Interval + Image = Wavelet: For Image Processing under Interval Uncertainty,Wavelets Are Optimal

In computer and electronic manufacturing, it is very important to be able to automatically check whether the surface mounted devices (SMD) are correctly placed on the printed circuit boards. The inspection of these boards has to be done on a shop floor, where statistical characteristics of the noise vary so much that, in essence, we only have interval estimates for this noise.We show that under this interval uncertainty, the optimal image processing technique consists of using Haar wavelets. Wavelets indeed lead to much better results than previously used Fourier transform techniques.On a more fundamental level, our result is a step towards solving an important problem related to wavelets: that wavelet transforms often empirically work much better than other methods, but there are very few theoretical explanations of this efficiency. Our results shows that, probably, such a theoretical explanation can be obtained if we take interval uncertainty into consideration.     

Automated thermal fuse inspection using machine vision and artificial neural networks

Machine vision is an excellent tool for inspecting a variety of items such as textiles, fruit, printed circuit boards, electrical components, labels, integrated circuits, machine tools, etc. This paper presents an intelligent system that incorporates machine vision with artificial intelligent networks to automatically inspect thermal fuses. An effective inspection flow is proposed to detect four commonly seen defects, including black-dot, small-head, bur, and flake during the production of thermal fuses. Backpropagation neural networks and learning vector quantization performance is compared in detecting the bur defect because of its illegibility. Different numbers of defective samples were screened out from a production line in a case study company and used to demonstrate the efficacy of the proposed system. Currently, the proposed inspection system is operating at the case study company, replacing four to six human inspectors. The system not only ensures the quality of the thermal fuses produced, but also reduced the cost of manual visual inspection.     

A case-based evolutionary model for defect classification of printed circuit board images

In this research, a case-based evolutionary identification model is developed for PCB defect classification problems. Image understanding is the first and foremost step in the inspection of printed circuit boards. This paper presents a two-phase method for the segmentation of printed circuit board (PCB) images. In the first phase, a set of defect images of several existing basic patterns are stored to form a concept space. In the second phase, a new pattern is evolutionally grabbed using some primitive operators generated by calculating the relative position of several similar cases in the concept space. The case-based reasoning system relies on the software agents derived from past experience within the domain database to determine what feature is required to deliver new patterns in satisfying user’s requirements. Experimental results show that the proposed approach is very effective in identifying the defect patterns.     

集成电路组装过程中裸芯片目检不合格类型与原因分析

裸芯片目检是集成电路组装过程中重要的检验步骤,用于剔除不合格品。以多个批次代表产品的裸芯片为样本,严格按照GJB548B方法2010.1内部目检标准进行目检,对目检过程中主要的不合格类型进行了统计和分析,得到最主要的不合格类型,并开展不合格原因分析及应对措施。针对几种占比较大的主要不合格类型,对芯片拾取、传递、保存等若干环节进行严格控制,有效降低了裸芯片目检不合格品数量。     

A scheduling strategy in the manufacture of printed circuit boards (PCBs) using Surface Mount Technology (SMT)

A scheduling strategy for a company that manufacturers printed circuit boards is presented. This firm makes on an average over 70 different ceramic boards in a month to customer specification using Surface Mount Technology. These hybrid circuit boards are made to order. Therefore, the objective in the scheduling strategy is to minimize the number of tardy jobs and minimize the makespan.     

Automated visual inspection: 1981 to 1987

This bibliography lists journal publications, conference papers, research technical reports, and articles from trade journals on automated visual inspection for industry which were published during the years from 1981 to 1987. More than 600 references are included. References are organized into 13 categories according to subject matter. The categories are (1) books, (2) conferences and workshops, (3) general discussions and surveys, (4) inspection of printed circuit patterns, (5) inspection of solder joints, (6) inspection of microcircuit photomasks, (7) inspection of integrated circuits and hybrids, (8) inspection of other electrical and electronics components, (9) surface inspection, (10) X-ray inspection, (11) other inspection applications, (12) system components, and (13) inspection algorithms. References listed in each category are arranged in chronological order. The purpose is primarily to provide a complete bibliography for those interested in automated visual inspection. Some general observations have been made for the above areas of activity summarizing the advances that have taken place and the problems that remain to be solved.     

An automatic inspection system for printed wiring board masks

This paper describes an automatic inspection system for printed wiring board masks. This system utilizes a hierarchical defect detection algorithm developed for inspecting high precision mask patterns for both printed wiring boards and integrated circuits. This algorithm makes use of geometrical characteristics of mask patterns to discriminate defects. Sufficient defect detection capability, as well as high inspection throughput, has been accomplished by hardware-implementation of the algorithm and inspection result utilization through retouching machines.     

Electric contacts inspection using machine vision

Machine vision is an excellent tool for inspecting a variety of industrial items such as textiles, printed circuit boards, electric components, labels, integrated circuits (IC), machine tools and fruits. In this paper, we propose machine vision-based inspection system for electric contact (EC), which are popularly used in switches, breakers and relays, and are important components in the electrical industry. The proposed system consists of three sub-systems, which inspect the top, side, and bottom surfaces of electric contact for different types of defects respectively. The system acquires the digital image of three views and classifies the surface defects including cracks, breaks, and scratches. For each view, this study develops different image pre-processing and feature extraction methods to enhance and detect the surface defects. The proposed system was implemented and verified using 229 samples collected from the EC production lines. Experimental results show the proposed system is effective and efficient in identifying EC defects.     

Optimal component-insertion sequenceplanning methodology for the semiautomatic assembly of printed circuit boards

One of the primary concerns in the manufacturing of printed circuit boards (PCBs) is the definition of optimum component-insertion sequences for manual and automated operations. The problem is dynamic and multiple feasible solutions can be found. The research work described in this paper has developed a component-insertion sequencing methodology and a proof-of-concept expert system for printed circuit boards. This system solves the component-insertion sequencing problem for semi-automated work cells which utilize a light guiding system to identify for the operator where to assemble the next component. The innovation of the methodology is the application of Artificial Intelligence and Expert Systems techniques to represent the human reasoning involved in semi-automated PCB assembly planning. Based on established assembly criteria, sequencing decision rules and data available from a CAD system, the methodology leads to optimum component-insertion sequences.     

A path planning algorithm for PCB surface quality automatic inspection

Journal of Intelligent Manufacturing - The surface quality inspection of industrial printed circuit board (PCB) is a vitally important link in its manufacturing process. To inspect surface defects...     

Understanding computer-aided manufacturing impact on total productivity

This paper presents a step-by-step procedure for assessing the impact of computer-aided manufacturing on total productivity. The Task-Oriented Total Productivity Measurement Model (TOTPM) was used in two studies. The first study deals with the comparison of the total and partial productivities of the manual and computer-aided method of manufacturing printed circuit boards. The second study shows a comparison of the productivities of two types of computer-aided method of assembling printed circuit boards. Both studies were conducted for a period of 10 weeks. Computer system design problems encountered during implementation are discussed as well as ways to correct these problems.     

机器视觉在印刷缺陷在线检测中的应用与研究

为了提高印刷缺陷检测准确性与效率,满足缺陷检测的实时性,提出了机器视觉技术应用于印刷缺陷在线检测并研究检测过程中的相关问题.设计印刷缺陷在线检测的方案及以数字信号处理器DSP为核心的视觉在线检测系统的硬件结构组成.研究图像预处理、图像匹配与缺陷检测的算法并加以改进使其满足缺陷检测的实时性.开发印刷品缺陷视觉检测软件,对缺陷检测流程进行仿真,验证检测方案与图像处理算法的可行性.     

Artwork production for multi-layer printed circuit boards by computer

This paper describes a computer system which integrates three types of numerical control machines in the production of artwork drawings and drill tapes for multi-layer printed circuit boards.     

Realization of a flow injection analysis in PCB technology

In this paper a microflow injection analysis (FIA) is presented, which was developed completely in printed circuit board (PCB) technology. The multilayer printed circuit board, which was made as stack of four individual printed circuit boards, contains both the passive and active fluid elements, and necessary electronics for the control and evaluation. For a reference reaction the FIA detects Fe³⁺. A calibration curve was recorded and a reproducibility measurement was carried out. An accuracy of 10% was reached. Data acquisition and control was made with the help of a PC and a Labview-program.     

Subminiature binary camera design for inspection and robotic assembly applications

The article describes the design and utilization of a small, lightweight digital camera intended to assist in robot assembly tasks and to provide a low cost visual inspection tool. The main operational features of the design are outlined together with some sample applications involving the identification of integrated circuit devices, and the location of assembly sites on a printed wiring board.