• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.403-406
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• 2006

A new medical X-ray PIV technique was developed using a conventional medical X-ray tube. To acquire images of micro-scale particles, the X-ray PIV system consists of an x-ray CCD camera with high spatial resolution, and a X-ray tube with small a focal spot. A new X-ray exposure control device was developed using a rotating disc shutter to make double pulses which are essential for PIV application. Synchronization methodology was also developed to apply the PIV technique to a conventional medical X-ray tube. In order to check the performance and usefulness of the developed X-ray PIV technique, it was applied to a glycerin flow in an opaque silicon tube. Tungsten particles which have high X-ray absorption coefficient were used as tracer particles. Through this preliminary test, the spatial resolution was found to be higher than ultrafast MRI techniques, and the temporal resolution was higher than conventional X-ray PIV techniques. By improving its performance further and developing more suitable tracers, this medical X-ray PIV technique will have strong potential in the fields of medical imaging or nondestructive inspection as well as diagnosis of practical thermo-fluid flows.

• 대한안전경영과학회지
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• 제12권4호
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• pp.73-80
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• 2010

The purpose of this study was to investigate the actual conditions of radiation safety supervision in animal clinics using inspection standard of X-ray generator for diagnosis. The surveys for inspection standard system, equipment condition, and safety supervision were carried out in 18 animal clinics randomly. The inspection standard included reproducibility of dose exposure, kVp, mAs, collimator accuracy test, collimator luminance test, X-ray view box luminance test, grounding system equipment test and external leakage current test. The surveys of equipment condition and safety supervision used one-on-one interview with 5 points measurement. As a result, 44.44% of reproducibility of dose exposure was proper, 81.25% of kVp test was good, and 100% of mAs test was appropriate. Also, 66.66% of collimator accuracy test was proper, 61.11% of collimator luminance test was good, 53.13% of X-ray view box luminance test was suitable. In addition, only 5.55% of grounding system equipment and ground resistance was proper, 63.64% of external leakage current test was appropriate in grounding system equipment test. The 100mA electric capacity of X-ray generator for diagnosis was popular with 44.44%, and its 55.56% was purchased used equipment. Monthly average of less than 50 times (61.11%) was top frequency in use, and no animal clinic had a thermo-luminescence dosimeter(TLD). The 16 animal clinics with radiation safety zone and 2 without radiation safety zone were appeared.

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.916-921
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• 2009

The technology to inspect and measure an inner structure of micro parts has become an important tool in the semi-conductor industrial field with the development of automation and precision manufacturing. Especially, the inspection skill on the inside of highly integrated electronic device becomes a key role in detecting defects of a completely assembled product. X-ray inspection technology has been focused as a main method to inspect the inside structure. However, there has been insufficient research done on the customized inspection technology for the flip-chip assembly due to the interior connecting part of flip chip which connects the die and PCB electrically through balls positioned on the die. In this study, therefore, it is implemented to detect shape error of flip chip bonding without damaging chips using an x-ray inspection system. At this time, it is able to monitor the solder bump shape by introducing an edge-extracting algorithm (exponential approximation function) according to the attenuating characteristic and detect shape error compared with CAD data. Additionally, the bonding error of solder bumps is automatically detectable by acquiring numerical size information at the extracted solder bump edges.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.302-304
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• 2004

Nuclear fuel elements containing dry recycling nuclear fuel pellets for the irradiation test in a reactor were remotely fabricated from spent PWR fuel materials in a hot cell. End closure welding as well as seal tube welding for thermal sensor of the elements was performed by Nd:YAG laser. The soundness of the end closure welds and seal tube welds for the elements were evaluated by a precise X-ray inspection system composed of a micro-focus X-ray generator with an image intensifier and a real time camera system. Then, helium leak test was performed for the elements. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection and helium leak test. The irradiation test for the fuel elements were successfully completed at the HANARO research reactor.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.695-698
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• 2014

화물 검색용으로 사용되고 있는 X-선 검색장치는 대상물의 단면 정보만을 제공하고 있기에 검색 대상체의 식별에 어려움이 있어 이에 대한 개선이 요구되어 왔다. 또한 대량의 화물 검색을 효율적으로 수행하기 위해서는 검색시스템에 대한 자동화가 요구되며 자동화를 위해서는 대상체를 식별하기 위한 다양한 식별자가 필요하다. 스테레오 X-ray 시스템은 기존의 검색 장치에 라인센서를 추가하여 검색 대상체에 대한 추가적인 정보를 제공함으로써 검색 효율을 높이도록 고안되었다. 본 논문에서는 선행 연구를 통해 개발된 스테레오 X-선 검색장치를 이용하여 다양한 물체에 대한 검색을 수행하며 형상정보를 복원하여 실제 값과의 비교를 통해 스테레오 방사선 스캔장치에 대한 성능분석을 수행하였다. 또한 본 논문에서 제시하는 3차원 형상복원 알고리즘을 통해 검색시스템을 자동화할 수 있는 새로운 식별자의 제공이 가능하다고 판단된다. 본 연구의 결과는 대형 화물 스캔 장치 및 고속화물 스캔 장치 개발을 위해 활용될 수 있다.

• 한국정보통신학회논문지
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• 제24권12호
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• pp.1711-1717
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• 2020

일반적으로 컨테이너 내부검사를 위해서는 최대 9MeV의 X-선을 사용한다. 이때 사용되는 X-선은 선형가속기를 통해 생성되며 일정한 세기의 X-선량이 시간의 변화에 관계없이 안정적으로 유지되어야 한다. 만약 발생되는 X-선의 세기가 일정하지 않다면 영상의 해상도와 대비도 등에 영향을 미칠 수 있으며 결과적으로 컨테이너 내부의 이상화물에 대한 검사에 영향을 미칠 수 있다. 그러므로 고화질의 영상을 획득하기 위해서는 발생되는 X-선 선량에 대한 지속적인 모니터링이 요구된다. 이와같은 선량 모니터링을 위하여, 본 연구에서는 고에너지 X-선 선량의 변화 측정을 위한 이온전리함 기반의 선량변화 측정장치를 개발하였고 환경변화에 따른 신호처리부의 성능변화를 확인하기 위하여 온도와 습도 변화에 의한 측정값의 변화를 관찰하였다. 또한, 고에너지 X-선 발생장치에서 발생되는 선량의 변화에 따른 응답특성변화를 측정함으로써 개발한 X-선 선량측정장치의 검증을 수행하였다. 측정결과 온도와 습도의 변화에 따른 성능의 차이가 크게 나타나지 않았으며 입사되는 선량의 변화에 따른 출력의 변화가 선형적이었다. 그러므로 개발한 이온전리함 기반의 선량변화측정장치는 고에너지 X-선의 선량변화의 측정에 적용하기에 적합함을 알 수 있었다.

• 전기학회논문지
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• 제63권1호
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• pp.145-149
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• 2014

In this study, using X-ray cargo container scanning device and to differentiate the concept of three-dimensional information extraction applied for X-ray scanning device as an ingredient in the rotation of the X-Ray Linear Pushbroom Stereo System by introducing the geometric How to model was introduced. Three-dimensional information obtained through the matching of a single voxel space filled with a random vector operations for each voxel in the three dimensional shape reconstruction algorithm using the definition, and in time, the time required for each step were analyzed. Using OpenCV in each step by applying parallelization techniques approximately 1.8 times improvement in the processing time of the check, but do not meet the target within one minute levels. The other hand, X-ray images by the primary process to convert the point View the results of real-time stereo through a three-dimensional could feel the comfort level.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.29-31
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• 2007

In this paper we propose an directional analytic approach in image data space for X-ray image which is detected from the X-ray projection system. Such a radiographic nondestructive testing has long been used for steel-tube inspection and weld monitoring. The welded area and thickness of steel-tube are detected from gradient radiating mechanism based on the evaluation of biased X-ray source position. The welded area is an ellipse type on low contrast X-ray image including noise. Noise originates from most of elements of the system. such as shielding CCD camera, imaging screen, X-ray source, inspected object, electronic circuits and etc.. Projection incorrectness and noise influence on imaging quality is to be represented by vertical pixels' distribution. Space analysis due to vertical direction also shows the segmental possibility between regions by visual edge evaluation.

• 제어로봇시스템학회논문지
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• 제8권1호
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• pp.21-27
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• 2002

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. A number of visual or optical technologies have been successfully applied to measure three-dimensional surfaces. However, those conventional visual or optical methods have inherent shortcomings such as occlusion and variant surface reflection. X-ray vision system can be a good solution to these conventional problems, since we can extract the volume information including both the surface geometry and the inner structure of any objects. In the x-ray system, the surface condition of an object, whether it is lambertian or specular, does not affect the inherent characteristics of its x-ray images. In this paper, we propose a three-dimensional x-ray imaging method to reconstruct a three dimensional structure of an object out of two dimensional x-ray image sets. To achieve this by the proposed method, two or more x-ray images projected from different views are needed. Once these images are acquired, the simultaneous algebraic reconstruction technique(SART) is usually utilized. Since the existing SART algorithms have several shortcomings such as low performance in convergence and different convergence within the reconstruction volume of interest, an advanced SART algorithm named as USART(uniform SART) is proposed to avoid such shortcomings and improve the reconstruction performance. Because, each voxel within the volume is equally weighted to update instantaneous value of its internal density, it can achieve uniform convergence property of the reconstructed volume. The algorithm is simulated on various shapes of objects such as a pyramid, a hemisphere and a BGA model. Based on simulation results the performance of the proposed method is compared with that of the conventional SART method.

• 반도체디스플레이기술학회지
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• 제20권2호
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• pp.126-130
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• 2021

The ball grid array is one of the packaging methods that used in high density printed circuit board. Solder void defects caused by voids in the solder ball during the BGA process do not directly affect the reliability of the product, but it may accelerate the aging of the device on the PCB layer or interface surface depending on its size or location. Void inspection is important because it is related in yields with products. The most important process in the optical inspection of solder void is the segmentation process of solder and void. However, there are several segmentation algorithms for the vision inspection, it is impossible to inspect all of images ideally. When X-Ray images with poor contrast and high level of noise become difficult to perform image processing for vision inspection in terms of software programming. This paper suggests the solution to deal with the suggested problem by means of using Mask R-CNN instead of digital image processing algorithm. Mask R-CNN model can be trained with images pre-processed to increase contrast or alleviate noises. With this process, it provides more efficient system about complex object segmentation than conventional system.