• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.24-29
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• 1996

The seniconductor, which is precision product, requires many inspection processes. The surface conditions of the semiconductor chip effect on the functions of the semiconductors. The defects of the chip surface is crack or void. Because general inspection method requires many inspection processes, the inspection system which searches immediately and preciselythe defects of the semiconductor chip surface. We propose the inspection method by using the computer vision system. This study presents an image processing algorithm for inspecting the surface defects(crack, void)of the semiconductor test samples. The proposed image processing algorithm aims to reduce inspection time, and to analyze those experienced operator. This paper regards the chip surface as random texture, and deals with the image modeling of randon texture image for searching the surface defects. For texture modeling, we consider the relation of a pixel and neighborhood pixels as noncasul model and extract the statistical characteristics from the radom texture field by using the 2D AR model(Aut oregressive). This paper regards on image as the output of linear system, and considers the fidelity or intelligibility criteria for measuring the quality of an image or the performance of the processing techinque. This study utilizes the variance of prediction error which is computed by substituting the gary level of pixel of another texture field into the two dimensional AR(autoregressive model)model fitted to the texture field, estimate the parameter us-ing the PAA(parameter adaptation algorithm) and design the defect detection filter. Later, we next try to study the defect detection search algorithm.

• 한국정밀공학회지
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• 제14권11호
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• pp.126-134
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• 1997

In this study, We made visual inspection system using Vision Board. It is consist of an illuminator (a fluorescent lamp), image input device (CCD (Charge-Coupled Device) camera), image processing system(Vision Board(FARAMVB-02)), image output device (video monitor, printer), and a measuring instrument(TELMN1000). Length measurement by visual inspection system make use of 100mm guage block(instead of calculating distance between a camera and a object). It measured horizontal and vertical length factor from 400mm to 650mm by increasing 50mm. In this place, measured horizontal and vertical length factor made use of length measure- ment of a injection. A measuring instrument used to ompare a measured length of a injection visual inspection system with it. In conclusion, length measurement of a injection compared a measuring instrument with visual inspecion system using length factor of 100mm gauge block. We find that maximum error of length is 0.55mm when it compar with the measuring value of two devices(FARAMVB-02, TELMN1000). Program of visual inspection system is made up Borland C++3.1.

• 한국정밀공학회지
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• 제25권5호
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• pp.69-76
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• 2008

Inner diameter of bearing race is automatically measured by complete inspection system after grinding process. Contact type three points supporting method is widely applied to automatic inner diameter measurement because of its excellent stability. However, the geometric consideration regarding three points supporting method is not sufficient. In this study, the error equation from geometric error analysis of three points supporting method is found. The effect of factors in the error equation is also investigated. The error equation is linear for difference of diameter in sample and master on range of tolerance. An error becomes more and more larger, when the distance of two supporting balls or the diameter of supporting ball are increased. In the result, some considerations are proposed for measurement of inner diameter by the three points supporting method.

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.67-74
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• 1998

A nondestructive quality inspection technique using acoustic impulse response method was developed for eggshell inspection. An experimental system was built to generate the impact force, to measure the response signal and to analyze the frequency spectrum. This system includes an impulse generating unit, an egg holding seal a microphone with preamplifier, and a DSP board installed on Personal Computer. A simple algorithm .was developed for crack detection. Using the developed system with algorithm, crack detection ability was evaluated and the error rate to estimate the normal egg as cracked was found to be 4% and the error rate to estimate the cracked egg as normal was also found to be 4%. This system could be adopted in industry with some modification.

• 품질경영학회지
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• 제17권2호
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• pp.158-167
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• 1989

In this paper, a model is presented which incoporates the possibility of quality control at each of the production stages. We consider the TYPE I error and the TYPE II error in inspection procedures. In addition to alternative quality control configurations, the model integrates the carrying costs of in-process and finished inventory, quality of production process, reprocessing including fixed and variable cost. Our policy determines the value of optimal lot-size and reprocessing batch size in reducing the total costs. A numerical example illustrates the model framework and highlights the role of the decision variables.

• 한국경영과학회지
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• 제38권1호
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• pp.1-13
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• 2013

Some systems such as missiles and ammunitions are used only one time in combat or emergency situation. Predicting correct storage reliability is very important for those systems which are inspected periodically. Many researches have been done for predicting the storage reliability using generally exponential or Weibull failure distribution. However, recent studies show the hazard functions follow various types of failure distributions. So in this paper, we proposed a generalized model that measures the storage reliability regardless of type of failure distributions. And this model reflects inspection error and failures that might be occurred during periodical check and within storage term as well.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.507-510
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• 1999

Inspection of BGAs presents several challenges for modem measurement equipment. No only must these systems be fast and accurate, they must deal with the special challenges presented by very small shiny metal spheres. For accurate measurement, we propose an algorithm which fits for estimating the accurate ball height using 2-D curve-fitting algorithm. The real boundary between two adjacent pixels and the real ball diameter are measured with subpixel accuracy Experimental results show that the proposed method calculates the ball height and diameter with subpixel accuracy and is robust in local noise with low measurement error.

• 한국산학기술학회논문지
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• 제13권6호
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• pp.2452-2457
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• 2012

산업현장에서는 품질검사 과정 중의 잘못된 불량판정을 감소시키기 위하여, 각 제품단위에 대하여 불량판정이 나왔을 경우 복수의 검사를 반복하여 수행하는 경우가 있다. 본 논문은 총 두 번까지의 연속된 검사를 허용하는 품질검사 프로세스에 대한 분석을 다루고 있다. 본 논문에서는 제품검사의 단계와 품질판정 상태를 모델링하는 수학적 도구로서 마르코프 체인이 사용되었다. 그리고 산업체의 생산관리 시스템에서 수집된 불량 판정률을 마르코프 체인 모델의 데이터로 사용하였다. 또한 본 논문은 제품의 품질 특성 별 최종 비율과 제품의 폐기율에 대한 이러한 연속적인 이중검사 허용 프로세스의 영향에 대하여 분석을 수행하였다. 분석 결과, 연속이중검사 허용이 정상 제품에 대한 불량판정을 줄이며, 그 결과 재료, 노동 및 기타 비용을 줄이는 데 기여할 수 있다는 것을 확인하였다

• 전자공학회논문지SC
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• 제44권5호
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• pp.11-17
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• 2007

각종 전자 제품 및 부품의 외관 검사는 사람의 시각에 의해 이루어졌다. 그러나 사람의 시각에 의한 외관 검사 결과는 검사자의 육체적, 정신적 상태에 따라 변하기 때문에, 일정한 검사 결과를 얻을 수 없다. 따라서 사람에 의한 검사 대신 머신 비전 검사 시스템이 많은 외관 검사 분야에 사용되고 있다. 그러나 머신 비전 시스템의 외관 검사 결과는 작업장의 조명에 의해 변하게 된다. 이에 본 논문에서 우리는 비전 검사 정확도의 개선을 위해 멱함수 변환과 히스토그램 지정 기법을 사용했다. 그리고 멱함수 변환과 히스토그램 지정 알고리즘을 통해서 비전 검사의 정확도를 향상시키고, 검사자의 육체적, 정신적 상태에 따른 검사 오류를 막을 수 있었다. 또한 이 시스템은 일반적인 검사 환경을 위해서 PC, CCD 카메라와 비주얼 C++ 만을 사용해서 개발됐다.

• 한국구조물진단유지관리공학회 논문집
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• 제9권4호
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• pp.217-226
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• 2005

본 연구는 비파괴 실험을 통해 공시체와 부재 시험체의 코어 공시체를 채취 후, 파괴실험과 비파괴 실험을 실시하여 압축강도의 추정식을 제안한 것으로, 그 결과는 다음과 같다. 혼화콘크리트에 대해 기존의 보통콘크리트 제안식을 적용하면 파괴압축강도와 추정강도간의 오차율이 발생하게 되므로, 본 연구에서는 혼화재 종류 및 시험방법에 따라 다음과 같은 추정식을 제안한다.