• Journal of the Korean Society for Nondestructive Testing
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• v.4 no.1
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• pp.11-22
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• 1984

In the straight beam inspection of ultrasonic wave, the method for evaluating flaw size by AVG diagram is useful as a method for the quantitative evaluation of results of ultrasonic flaw detection. This study was carried out the measure the size of circular flat flaw with the inclination by straight beam inspection and could be decreased the error of application due to the inclination of flaw by AVG diagram in consideration of correction coefficient. From the result of the experiment, the error by means of the application of experimental values to AVG diagram was increased as the inclination angle grows. Also, it n s increased the error of application as the detecting frequency and diameter of flaw grows in the same inclination angle. In case of diameter of flaw 6mm, AVG diagram could be applied to the inclination angle $3^{\circ}$ for 5 MHz, $7^{\circ}$ for 2.25 MHz, $15^{\circ}C$ for 1 MHz in the range of 20% error and the theory was concided with the experiment to $5^{\circ}C$ for 5 MHz, $10^{\circ}C$ for 2.25 MHz, $15^{\circ}C$ for 1 MHz in the range of 10% error by correction eq. (45) due to the inclination angle. Therefore, it is considered that the results obtained from this study will be somewhat helpful informations for the size evaluation of circular flat flaw with the inclination.

• Journal of Radiation Industry
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• v.8 no.3
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• pp.147-153
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• 2014

This paper describes a large area CMOS image sensor module Implementation using the precision align inspection program. This work is needed because wafer cutting system does not always have high precision. The program check more than 8 point of sensor edges and align sensors with moving table. The size of a $2{\times}1$ butted CMOS image sensor module which except for the size of PCB is $170mm{\times}170mm$. And the pixel size is $55{\mu}m{\times}55{\mu}m$ and the number of pixels is $3,072{\times}3,072$. The gap between the two CMOS image sensor module was arranged in less than one pixel size.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.359-363
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• 2017

The LED (Liquid Emitting Diode) frame device is a big part of the representative display industry in Korea. LED is an essential part for TV, monitor, notebook, and mobile phone. In Japan, Taiwan, China and other countries, investment in LEDs has been strengthened, and productivity has become an important issue. However, as the size of the parts becomes smaller, the inconsistent inspection by the human eye becomes a problem of reliability, so that the automatic inspection process becomes an essential issue in the field of LED module inspection. In this paper, we investigate defects in visual inspection process using computer vision technology. The inspection of the LED frame is made quickly and accurately, thereby improving the efficiency of the process and shortening the inspection time. As a result of applying the inspection system to the field, we confirmed that it is possible to inspect quickly and accurately.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.1
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• pp.115-120
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• 2015

Evaluating product quality level is necessary before the manufactured items are delivered to the customer. When the amount of the items to be manufactured is limited and the product is of high price and should be evaluated by destructive testing, the number of samples to be tested should be as small as possible. This paper presents a small-sample inspection method using hyper-geometric distribution and Bayesian approach for finite small-sized population. A method of determining the minimum sample size is presented for given population size, allowable number of defectives, warranteed defective level, and confidence level which is the degree of confidence on the product quality level recognized by both the producer and the customer.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.4
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• pp.206-213
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• 2003

In this paper, we propose a design method of automatic thickness measurement and defect inspection system, which measures the thickness of the autoclaved lightweight concrete block and inspects the defect on a real-time basis. The image processing system was established with a CCD camera, an image grabber, and a personal computer without using assembled measurement equipment. For the realization of proposed algorithm, the preprocessing method that can be applied to overcome uneven lighting environment, threshold decision method, unit length decision method in uneven condition with rocking objects, and the curvature calibration method of camera using a constructed grid are developed. From the experimental results, we have found that the required measurement accuracy specification is sufficiently satisfied using our proposed method.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.5
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• pp.27-38
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• 2021

The physical condition assessment criteria of fill dam safety inspection are now weakly regulated and inappropriate for small agricultural reservoirs since these criteria have fundamental backgrounds suitable for large-scale dams. This study proposes the degree (critical values) of defects for the quantitative condition assessment of the embankment in order to prepare the condition assessment criteria for a small reservoir with a storage capacity of less than one (1) million cubic meters. The critical values of defects were calculated by applying the method that considers the size ratios based on the dimensional data of reservoirs, and the method of statistical analysis on the measured values of the defect degree which extracted from comprehensive annual reports on reservoir safety inspection. In comparison with the current criteria, the newly proposed critical values for each condition assessment item of the reservoir embankment are presented in paragraphs 4 and 6 of the conclusion. In addition, this study presents a method of displaying geometric figures to clarify the rating classification for condition assessment items with the two defect indicators.

• ETRI Journal
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• v.35 no.1
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• pp.154-157
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• 2013

This letter proposes a memory-based parallel string matching engine using the compressed state transitions. In the finite-state machines of each string matcher, the pointers for representing the existence of state transitions are compressed. In addition, the bit fields for storing state transitions can be shared. Therefore, the total memory requirement can be minimized by reducing the memory size for storing state transitions.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.4
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• pp.793-802
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• 1997

A sampling plan is presented for situations where sampling inspection is based on the quality characteristic of interest and items in rejected lots are screened based on a correlated variable. A cost model is constructed which involves the costs of misclassification errors, sampling and screening inspections. A method of finding optimal values of sample size, acceptance number and cutoff value on the correlated variable is presented, and numerical studies are given.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.16-25
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• 2008

The micro needle means the ultrafine probe of 'Probe Card'. The size of micro needle is so minute that it is difficult to minute that it is difficult to inspect it with eyes. On the other hand it is very critical if there is a defect in micro needle of probe card. In this study, we developed an automatic visual inspection system for finding defect status in probe angle, tip length and diameter. Through the experimental results, we could find that our proposed method is better than human-eyes inspection method in accuracy and inspection speed, and also in robustness to lighting circumstances.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.63-69
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• 2014

RFIDs have not become widespread as expected partly due to the cost, size, read range, and reliability problems of tags. The success rate of reading must be improved in order for RFIDs to be widely adopted. Quality control of tags is crucial to meet this requirement. In this study, we designed and implemented a high-performance reader used in inspection equipment that conducts prior inspection of tags. To improve performance of the developed reader, the baseband modem and command processor (CP) were designed using H/W logic and implemented with FPGA. The inspection of small pitch inlays was made possible through the antenna shielding device and H/W command processor function. This equipment enables accurate evaluation of performance and identification of tags satisfying a given read range. By contributing to sort out defective tags, the results can ultimately lead to more stable RFID services.