• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.109.2-109
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• 2001

In the PCB assembly lines, as components become more complex and smaller, the conventional inspection method using traditional ICT and function test show their limitations in application. The automatic optical inspection(AOI) gradually becomes the alternative in the PCB assembly line. In Particular, the PCB inspection machines need more reliable and flexible object recognition algorithms for high inspection accuracy. The conventional AOI machines use the algorithmic approaches such as template matching, Fourier analysis, edge analysis, geometric feature recognition or optical character recognition (OCR), which mostly require much of teaching time and expertise of human operators. To solve this problem, in this paper, a statistical learning based part recognition method is proposed. The performance of the ...

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.149-156
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• 2019

송전선로 현장에서는 2017년도부터 송전선로 순시 점검에 드론을 활용하기 시작했다. 전력연구원의 송전선로 드론점검 시범적용을 시작으로 현재 4개 지역본부에서 전력연구원이 개발한 송전선로 드론순시 점검기술을 현장에서 사용 중에 있다. 현재 점검드론 지상관제시스템을 활용하여 드론은 자동비행하고 광학줌 카메라와 열화상카메라의 짐벌은 현장작업자가 수동으로 조종하여 송전선을 촬영하는 체계로 운영되고 있다. 송전선로 드론점검은 작업자가 접근하기 어려운 지역, 예를 들면, 강횡단지역, 해월구간, 산간지역 등에 위치한 송전선로가 그 주요대상이다. 특히 산간지역의 경우, 점검드론과 지상관제시스템 사이에 장애물이 많고 철탑 구조물이 전파간섭을 일으켜 간헐적으로 통신장애가 일어나곤 한다. 이런 통신장애는 계획된 경로로 비행하는 점검드론의 자동비행에는 영향이 없지만, 카메라 짐벌의 제어에는 영향을 주어 제어불능 상태로 되는 경우가 있다. 또한, 카메라 짐벌의 제어가 원활하더라도 통신장애로 인해 발생하는 간헐적 영상 끊김 현상은 현장작업자가 점검대상을 잃어 카메라 짐벌 조정을 불가능하게 한다. 그러므로 본 논문에서는 간헐적 짐벌제어 끊김이나 영상 끊김 현상이 발생하더라도 지속적으로 송전선을 점검할 수 있도록 하기 위하여 딥러닝 기반 영상인식을 통해 송전선을 자동으로 추적하는 카메라 짐벌을 개발하여 현장 시험한 결과를 소개하고자 한다.

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.45-50
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• 2005

This paper proposed an efficient manufacturing system using the OMM (on-machine measurement) system. The OMM system is software-based 3D modeler for inspection on machine, and it is interfaced with machine tools via RS232C. The software is composed of two inspection modules; one is touch probe operating module, and the other is laser displacement sensor operating module. The module for touch probe needs the inspection feature extracted from CAD data. The touch probe moves to workpiece by three operating modes as follows: manual, general and automatic mode. The operating module of the laser displacement sensor is used to inspect profiles and very small holes. An advantage of this inspection method is the ability to execute on-line inspection during machining or afterward. The efficiency of proposed system which can predict and define the machining errors of each process was verified, so the developed system was applied to inspect a mold-base (cavity, core).

• 대한전자공학회논문지SP
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• 제47권1호
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• pp.91-96
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• 2010

본 논문에서는 핵연료봉의 변형에 대한 고정도 검사방법을 제안한다. 핵 연료봉과 이를 관측하는 영상 센서의 광축을 수직으로 구성한다. 영상 센서의 광축을 기준으로 45도 또는 그보다 높은 각도로 레이저 라인빔을 연료봉 표면에 조사하면 연료봉의 수평 방향 변위가 영상 센서에서는 수직 방향 변위로 관측된다. 핵 연료봉 표면에 일정 각도로 입사된 레이저 라인빔이 영상 센서면에서는 일정 두께를 갖는 포물선 형태로 관측되게 된다. 센서 화면에 나타나는 일정 두께의 포물선을 영상처리하여 타원으로 모델링하고 타원의 장축과 단축의 기울기를 구한다. 포물선의 변곡점과 모델링한 타원의 장축과 단축이 교차하는 지점을 특징점으로 추출한다. 이와 같은 영상처리 알고리즘을 이용하여 핵 연료봉의 수평방향 변위에 따른 특징점 좌표의 수직방향 편차를 계산한다. 크러드가 형성된 핵연료봉 시편에 대해 고해상도 영상센서를 사용하여 실험한 결과 중성자 조사후 핵연료봉의 변형 검사기준인 $150{\mu}m$ 보다 3배 이상 개선된 $50{\mu}m$ 이하의 검사 정밀도를 달성하였다.

• 센서학회지
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• 제27권5호
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• pp.328-334
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• 2018

The paper reviews an improved continuous-wave (CW) terahertz (THz) imaging system developed for nondestructive inspection, such as CW-THz quasi-time-domain spectroscopy (QTDS) and interferometry. First, a comparison between CW and pulsed THz imaging systems is reported. The CW-THz imaging system is a simple, fast, compact, and relatively low-cost system. However, it only provides intensity data, without depth and frequency- or time-domain information. The pulsed THz imaging system yields a broader range of information, but it is expensive because of the femtosecond laser. Recently, to overcome the drawbacks of CW-THz imaging systems, many studies have been conducted, including a study on the QTDS system. In this system, an optical delay line is added to the optical arm leading to the detector. Another system studied is a CW-THz interferometric imaging system, which combines the CW-THz imaging system and far-infrared interferometer system. These systems commonly obtain depth information despite the CW-THz system. Reportedly, these systems can be successfully applied to fields where pulsed THz is used. Lastly, the applicability of these systems for nondestructive inspection was confirmed.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1999년도 춘계 학술발표회 논문집
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• pp.171-176
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• 1999

Nondestructive inspection and accompanying life analysis based on fracture mechanics were the major conventional methods for evaluating remaining life of critical high temperature components in power plants. By using these conventional methods, it has been difficult to perform in-service inspection for life prediction. Also, quantitative damage evaluation due to unexpected abrupt changes in operating temperature was almost impossible. Thus, many efforts have been made for evaluating remaining life during operation of the plants and predicting real-time life usage values based on the shape of structures, operating history, and material properties. In this study, a core software for on-line life monitoring system which carries out real-time life evaluation of a critical component in power boiler(high temperature steam headers) is developed. The software is capable of evaluating creep and fatigue life usage from the real-time stress data calculated by using temperature/stress transfer Green functions derived for the specific headers and by counting transient cycles. The major benefits of the developed software lie in determining future operating schedule, inspection interval, and replacement plan by monitoring real-time life usage based on prior operating history.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.1783-1786
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• 2003

In this paper, an automated line-defect detection method for TFT-LCD panel is presented. A DFB(Directional Filter Bank) and line-projection method are used to find line-defect which is one of the major defects occurred in TFT-LCD panel. The experimental results show that the proposed algorithm gave promising results for applying automated inspection technique for TFT-LCD panel.

• 한국자동차공학회논문집
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• 제23권3호
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• pp.344-351
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• 2015

Braking force inspection of vehicles in service is certainly one of the most important characteristics that affect vehicle safety. Up to now, in domestic country, the regular safety inspection of vehicles in service has been tested with a roller type brake test (a static braking force inspection system). But, in EU and USA etc. in recent years, it has been tested with a plate type brake test (a dynamic braking force inspection system). In this study, to compare the characteristics of above two test systems, the correlations for the results of braking force are evaluated statistically. As the results, in the case of main braking force, the range of the $R^2$ of the deviation for the left and right side is 0.5386 ~ 0.6231 in the rear axle and 0.0032 ~ 0.0052 in the front axle respectively, then the $R^2$ in the front axle is lower than that in the rear axle and the total variation is unexplained by the least-squares regression line statistically. Also, the p-value for the deviation of the left and right in the front axle is 0.4839 ~ 0.5755, then it has nonsignificant in the front axle. Therefore, the static braking force inspection system can not reflect the inertia force that there is a load transfer from the rear axle to the front axle during braking. Accordingly, it is necessary to adopt the dynamic braking force inspection system which can reflect the inertia force on the regular vehicle safety inspection in domestic country.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.48-51
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• 1997

This paper presents the algorithm of FIC inspection in chip mounter. When device is mounted on the PCB, it is impossible to get zero defects since there are many problems which can not be predicted. Of these problems, devices with bent corner leads due to mis-handling and which are not placed at a given point measured along the axis are principal problem in SMT(Surface Mounting Technology). In this paper, we proposed a new algorithm based on the Radon transform which uses a projection to inspect the FIC(Flat Integrated Circuit) device and compared this method with other algorithms. We measured the position error and applied this algorithm to our image processing board which is characterized by line scan camera. We compared speed and accuracy in our board.

• Journal of Biosystems Engineering
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• 제35권3호
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• pp.197-205
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• 2010

An automatic echelon feeder of brown rice was presented for quality inspection system using color image processing. A echelon feeder was developed with vibratory feeder and cylindrical indent singulator having oblique light. The vibratory feeder consisted of a hopper, electromagnetic vibrator and multichannel grooves and supply the grain sample to the singulator. The feeding performance such as feed rate, blocking frequency of the channel was dependent on the size of groove and vibration pattern. A cylindrical indent singulator consisted of a rotating cylinder, prisms and a tungsten-halogen light source. It delivered grain kernels under the camera in a echelon form and illuminate the kernels with oblique ray and ambient light. The size of the indents installed on the surface of the rotating cylinder was determined by the dimensions of the paddy and a small triangular prism was placed in each indent to apply $ 20^{\circ}$ oblique light to the grain kernel.