• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.201-207
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• 1999

The automatic pinhole detection system is described. The goal of this project is to study the feasibility test of the new concept for hole detection. The developed method is able to detect almost 50$\mu\textrm{m}$ pinhole by evaluating the shining of the light as if there is pinhole in the strip. Moreover, it is possible to inspect up to the 200$\mu\textrm{m}$ inclined pinhole. The system cosists of three main functional parts: the source part of the light which is using the linear halogen lamp, the image gathering part which is using a line CCD and the image processing part. The light spot can be controlled and optimized corresponding to the situation of the strip. To eliminate back ground noise, the binary image processing method is adopted.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.17-22
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• 2012

In this paper, a photoelectric image detection system is proposed using an APD(Avalanche Photodiode) sensor, a LED illuminator, and fiberoptic waveguides. This proposed pinhole detection system can detect the pinholes of 100 micron with the speed rate of 1,000mpm(meter per minute). And detecting performance of image system is improved by the SQL based DB analysis of classifying pinhole's detected location and size using image detection algorithms.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.663-668
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• 2016

In single-photon-emission computed tomography (SPECT) with a pixelated semiconductor detector (PSD), not only pinhole collimators but also parallel-hole collimators are often used in preclinical nuclear-medicine imaging systems. The purpose of this study was to evaluate and compare pinhole and parallel-hole collimators in a PSD. For that purpose, we paired a PID 350 (Ajat Oy Ltd., Finland) CdTe PSD with each of the four collimators most frequently used in preclinical nuclear medicine: (1) a pinhole collimator, and (2) low-energy high-resolution (LEHR), (3) low-energy general-purpose (LEGP), and (4) low-energy high-sensitivity (LEHS) parallel-hole collimators. The sensitivity and spatial resolution of each collimator was evaluated using a point source and a hot-rod phantom. The highest sensitivity was achieved using LEHS, followed by LEGP, LEHR, and pinhole. Also, at a source-to-collimator distance of 2 cm, the spatial resolution was 1.63, 2.05, 2.79, and 3.45 mm using pinhole, LEHR, LEGP, and LEHS, respectively. The reconstructed hot-rod phantom images showed that the pinhole collimator and the LEHR parallel-hole collimator give a fine spatial resolution for preclinical SPECT with PSD. In conclusion, we successfully compared different types of collimators for a preclinical pixelated semiconductor SPECT system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.2
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• pp.91-96
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• 2014

An acoustical model for detecting the leak location in a buried gas pipeline has been developed. This model is divided into an experimental model for sound diagnosis, and a theoretical model for sound prediction, which is based on the transfer matrix method, representing the sound pressure and the volume velocity as state variables. The power spectrum is measured by attaching only one microphone to the closed end pipe. It has been shown that the response magnitude of acoustic pressure signals calculated by the acoustical model depends upon the thickness and diameter of a pinhole. The validity for the acoustical model has been verified through a comparison between the measured and calculated results.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.285-293
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• 2000

Purpose: A prospective comparison was made between imaging with Tc-99m pertechnetate (Tc-99m) and Ioine-131 (I-131) for the detection of residual and metastatic tissue after total thyroidectomy in patients with well-differentiated thyroid carcinoma. Materials and Methods: Initially our patients had imaging with Tc-99m, followed by I-131 within 3 days. The study included 21 patients who had ablation with high dose of I-131 ranging from 100 mCi to 150 mCi. Planar and pinhole images were acquired for both Tc-99m and I-131. Diagnostic images of Tc-99m and I-131 were compared with post-therapy images. Degree of uptake on Tc-99m and I-131 images was scored by four point scale and compared. Results: The results of the Tc-99m study were: 16 of 19 studies (84%) were positive on simple planar images, but 19 of 20 studies (95%) were positive on pinhole images. Conventional I-131 diagnostic imaging on the other hand showed that all studies (100%) were positive on both planar and pinhole images. There was a significant difference in degree of uptake between Tc-99m and I-131 planar images (p<0.05). Only one case of Tc-99m scintigraphy was negative on both planar and pinhole studies (false negative). There was no distant metastasis on the therapeutic I-131 images. Conclusion: Tc-99m scan using pinhole in certain clinical situations is an alternative to the I-131 scan in detecting thyroid or lymph node metastasis prior to the first ablative treatment after thyroidectomy for well-differentiated thyroid carcinoma.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.617-626
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• 2019

This study analyzes the optimal location of gas detectors through the gas dispersion in a cargo compressor room of a 174K LNG carrier equipped with high-pressure cargo handling equipment; in addition, we propose a reasonable method for determining the safety regulations specified in the new International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC). To conduct an LNG gas dispersion simulation in the cargo compressor room-equipped with an ME-GI engine-of a 174 K LNG carrier, the geometry of the room as well as the equipment and piping, are designed using the same 3D size at a 1-to-1 scale. Scenarios for a gas leak were examined under high pressure of 305 bar and low pressure of 1 bar. The pinhole sizes for high pressure are 4.5, 5.0, and 5.6mm, and for low pressure are 100 and 140 mm. The results demonstrate that the cargo compressor room will not pose a serious risk with respect to the flammable gas concentration as verified by a ventilation assessment for a 5.6 mm pinhole for a high-pressure leak under gas rupture conditions, and a low-pressure leak of 100 and 140 mm with different pinhole sizes. However, it was confirmed that the actual location of the gas detection sensors in a cargo compressor room, according to the new IGC code, should be moved to other points, and an analysis of the virtual monitor points through a computational fluid dynamics (CFD) simulation.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.475-481
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• 2014

The aim of this work was to develop the gamma camera system for small animal gamma imaging and environmental radiation monitoring imaging using a parallel hole collimator and pinhole collimator. The small gamma camera system consists of a CsI(Tl) scintillation crystal with 6 mm in thickness and $50{\times}50mm$ in area coupled with a Hamamatsu H8500C PSPMT, are resistive charge divider, pre-amplifiers, charge amplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a computer for control and display. We have developed a radiation monitoring system composed of a combined pinhole gamma camera and a charge-coupled devices (CCD) camera. The results demonstrated that the parallel hole collimator and pinhole collimator gamma camera designed in this study could be utilized to perform small animal imaging and environmental radiation monitoring system. Consequently in this paper, we proved that our gamma detector system is reliable for a gamma camera which can be used as small animal imaging and environmental radiation monitoring system.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.907-911
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• 2000

타포린 제조 공정에서 함침의 발생 여부를 검사하는 것은 동 업계의 중요한 문제이다. 본 논문에서는 모폴로지를 사용한 함침 검사를 수행하였다. 모폴로지를 이용한 변환들 중의 하나인 Top hat 변환을 사용하였으며, 이 변환은 완만하게 불균일한 배경에서 급격한 변화를 가지는 물체를 추출하는데 탁월한 성능을 가진다. 이를 사용한 결과, 250dpi 영상에서 0.2mm 이상 크기의 함침을 검출할 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.107-112
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• 2020

Recently, as the field of use of drones is diversified, it is actively used not only for surveying but also for search and rescue work. In these applications it is very important to know the location of the target or the location of the UAV. This paper proposes a target detection method using images taken from drones. The proposed method calculates the latitude and longitude information of the target by finding the location of the target by comparing it with the image to find the image taken by the drone. The exact latitude and longitude information of the target is calculated by calculating the actual distance corresponding to the distance of the image image using the characteristics of the pinhole camera. The proposed method through the actual experiment confirmed that the latitude and longitude of the target was accurately identified.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.742-747
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• 2015

The quality of steel plate products is determined by the number of defects and the process problems are estimated by shapes of defects. Therefore pinholes defects of cold rolled steel have to be controlled. In order to improve productivity and quality of products, within each production process, the product is inspected by an adequate inspection system individually in the lines of steelworks. Among a number of inspection systems, we focus on the pinholes detection system. In this paper, we propose an embedded system using FPGA which can detect pinholes defects. The proposed system is smaller and more flexible than a traditional system based on expensive frame grabbers and PC. In order to detect consecutive defects, FPGAs acquire two dimensional image and process the image in real time by using correlation of lines. The proposed pinholes detection algorithm decreases arithmetic operations of image processing and also we designed the hardware to shorten the data path between logics due to decreasing propagation delay. The experimental results show that the proposed embedded system detects the reliable number of pinholes in real time.