• 한국콘텐츠학회논문지
• /
• 제10권6호
• /
• pp.329-335
• /
• 2010

디지털 방사선시스템에서의 의료영상 획득의 방법은 X선을 조사하고, 반도체 디텍터(Detector)를 이용하여 직접 및 간접으로 변환하여 기존 업체마다 여러 가지 알고리즘을 적용하여 적절한 이미지 프로세싱을 거쳐서 임상의 적정한 영상을 획득한다. 방사선과에서 적절한 의료 영상 형성을 위하여 적용하는 이미지 프로세싱 파라미터(Image Processing Parameters)는 Edge, Frequency, Contrast, Latitude, LUT, Noise 등의 영상 증강의 과정은 기술력 및 업체 알고리즘에 따라 다르게 적용되고 있다. 따라서 본 논문에서는 디지털 방사선 환경에서의 최종의 임상 영상을 위한 이미지 증강의 파라미터들의 적정 세팅 값의 기준을 제시하고자 한다. 그리고 각 병원들의 의료 영상을 바탕으로 이미지 프로세싱 파라미터들을 변화하여 각 파라미터들의 세부적인 기준 세팅값을 연구하며, 실제적인 파라미터 변화에 대한 적합한 의료 영상을 디지털방사선시스템의 영상 평가 방법을 도식화하여 결과를 제시하고, 향후 임상에서 적응 및 활용 가능한 객관적인 영상 파라미터에 대한 특성 평가의 응용을 정립하고자 한다. 또한 다양한 표본 병원의 디지털 방사선 환경에서 적정 파라미터 값들을 조사하여 임상에서 영상의 화질에 미치는 영향으로 특성 평가의 객관적인 기준의 변조전달함수(MTF)의 공간해상력을 제시하고 한다.

• 비파괴검사학회지
• /
• 제27권3호
• /
• pp.262-267
• /
• 2007

Detection of gas leak from a tube is a very important issue in the quality control of machines such as the heat exchanger of an air-conditioner, because leakage of operating gas directly reduces the performance of machines. The acoustic emission (AE) method is a common way to detect leak of gas, however its application under the environment of mechanical vibration is restricted since most AE detectors are very sensitive to external vibration noise. In order to overcome this problem, we propose a method based on the mode analysis of the Lamb wave. In this method, the dominant Lamb mode and its frequency are found first, and then a proper band-pass filter is used to retain only this frequency component. In this way, we could improve the SNR (signal-to-noise ratio) of AE signal generated by gas leak from the tube even under vibratory environment.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 추계학술발표회논문집(1)
• /
• pp.21-26
• /
• 1996

The identification of radioactive source in a medium with a limited number of external detectors is introduced as an inverse radiation transport problem. This kind of inverse problem is usually ill-posed and severely under-determined, however, its applications are very useful in manu fields including medical diagnosis and nondestructive assay of nuclear materials. Therefore, it is desired to develop efficient and robust solution algorithms. As an approach to solving inverse problems, an artificial neural network is proposed. We develop a modified version of the conventional Hopfield neural network and demonstrate its efficiency and robustness.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.131.5-131
• /
• 2001

A new measurement method to measure vibrational motions of objects is presented. The original principle is similar to the previous work that utilized a 3-facet mirror to obtain three dimensional positions and orientations of rigid bodies. While the previous work was presented for only stationary objects, in this paper, we newly investigate the feasibility of this method for dynamic applications. The 3-facet mirror that looks like a triangular pyramid having an equilateral cross-sectional shape. The mirror has three lateral reflective surfaces inclined 45 degrees to its bottom surface, and its mounted on the object whose motion is to be measured, As optical components, a He-Ne laser source and three position-sensitive detectors(PSD) are used. The laser beam is emitted from the He-Ne laser source located at the upright position and vertically incident to the top of the 3-facet ...

• Toxicological Research
• /
• 제12권2호
• /
• pp.163-169
• /
• 1996

The focus of this study was to investigate the suitable analytical methods for measurement of sulfamerazine and its metabolite in shrimp hepatopancreas and tail tissue, in addition to the methods for the optimization of solid-phase extraction cartridge conditions and the elucidation of sulfamerazine concentrations in aqueous buffer using HPLC with UV and EC detectors. Compared with UV detector the EC detector appears to be 10 times more sensitive than that of the UV detector. After the shrimp was exposed to 10 ppm sulfamerazine, the accumulation levels of sulfamerazine and its metabolite in tail tissue, which is edible portion, were considerably lower than 0.1 ppm. The data indicate that sulfamerazine continues to be a candidate for use at levels of sulfamerazine concentration used in aquaculture of shrimp.

• 천문학회보
• /
• 제44권1호
• /
• pp.58.3-58.3
• /
• 2019

Optical intensity interferometry, developed in the 1950s, is a simple and inexpensive method for achieving angular resolutions on microarcsecond scales. Its low sensitivity has limited intensity interferometric observations to bright stars so far. Substantial improvements are possible by using avalanche photodiodes (APDs) as light detectors. We present here the results of laboratory measurements with a prototype astronomical intensity interferometer using APDs in continuous ("linear") detection mode - arguably, the first of its kind. We used two interferometer configurations, one with zero baseline and one with variable baseline. Using a superluminous diode as light source, we unambiguously detected Hanbury Brown-Twiss photon-photon correlations at very high significance. From measuring the correlation as function of baseline, we measured the angular diameter of the light source, in analogy to the measurement of the angular diameter of a star. Our results demonstrate the possibility to construct large astronomical intensity interferometers that can address a multitude of astrophysical science cases.

• Nuclear Engineering and Technology
• /
• 제50권3호
• /
• pp.432-438
• /
• 2018

The occurrence of saturation in the CR-39 detector reduces and limits its detection dynamic range; nevertheless, this range could be extended using spectroscopic techniques and by measuring the net bulk rate of the saturated CR-39 detector surface. CR-39 detectors were irradiated by 1.5 MeV high alpha-particle fluence varying from $0.06{\times}10^8$ to $7.36{\times}10^8\;alphas/cm^2$ from Am-241 source; thereafter, they were etched in a 6.25N NaOH solution at a temperature of $70^{\circ}C$ for different durations. Net bulk etch rate measurement of the 1.5 MeV alpha-irradiated CR-39 detector surface revealed that rate increases with increasing etching time and reaches its maximum value at the end of the alpha-particle range. It is also correlated with the alpha-particle fluence. The measurements of UV-Visible (UV-Vis) absorbance at 500 and 600 nm reveal that the absorbance is linearly correlated with the fluence of alpha particles at the etching times of 2 and 4 hour. For extended etching times of 6, 10, and 14.5 hour, the absorbance is saturated for fluence values of $4.05{\times}10^8$, $5.30{\times}10^8$, and $7.36{\times}10^8\;alphas/cm^2$. These new methods pave the way to extend the dynamic range of polymer-based solid state nuclear track detectors (SSNTDs) in measurement of high fluence of heavy ions as well as in radiation dosimetry.

• 한국ITS학회 논문지
• /
• 제7권4호
• /
• pp.49-60
• /
• 2008

현재 비디오 영상처리시스템(VIPS: Video Image Processing System)은 실시간으로 들어오는 영상정보를 분석하여 유용한 정보를 제공하고, 하나의 카메라로 여러 차로를 동시에 감시할 수 있는 알고리즘으로 교통량, 속도뿐만 아니라 밀도 및 점유율 등 다양한 정보를 제공하나, 안전지대에서는 효과적이지 못한다. 그러나, 영상검지시스템에서 개별차량에 대한 추적시스템으로 개발할 경우 사고 및 차로 변경의 위험요소 감지 등 실시간으로 보다 다양한 정보를 제공할 수가 있다. 본 논문은 컴퓨터비전 기술을 이용하여 개별차량의 추적시스템을 개발하였으며, 이 시스템을 실제 도로영상에 적용하여 Tripwire에서 수집할 수 있는 교통정보뿐만 아니라 사고, 상충정보 등 다양한 정보를 제공한다. 본 연구의 검증을 위하여 개별차량 추적시스템으로 1) 돌발상황 감지 2) 급차로 변경과 같은 비정상적인 차량흐름의 경우를 감지하는 실험을 수행하였다.

• 한국ITS학회 논문지
• /
• 제22권4호
• /
• pp.97-113
• /
• 2023

전방 낙하물과 같은 돌발상황이 발생했을 때 신속하고 적절한 정보 제공은 도로 위 이용자들의 편의를 가져다주고 2차 교통사고 또한 효과적으로 줄일 수 있다. 도로 상의 돌발상황은 현재 국내에서 루프 검지기나 CCTV 등 ITS 기반 검지 체계를 사용하여 주로 검지하고 있다. 이러한 방식은 검지기의 검지 구간에서의 도로 위 데이터만을 얻을 수 있다. 때문에, 기존 ITS 기반 검지체계의 공간적 음영구간에서 돌발상황을 찾아내기 위하여 새로운 검지 수단이 필요하다. 이에 본 연구에서는 차량 내 설치된 단말기에서 촬영된 영상으로부터 돌발상황을 검지 및 분류하는 ResNet 기반 알고리즘을 제안한다. 국내 고속도로 전방 주행영상을 수집하였고, 돌발상황 유형을 클래스로 정의하여 각 데이터를 라벨링한 후, 제안한 알고리즘으로 데이터를 학습시켰다. 학습 결과, 개발한 알고리즘은 데이터 수가 상대적으로 적었던 일부 클래스를 제외하고 정의한 돌발상황 클래스에 대하여 높은 검지율을 보였다.

• 한국정밀공학회지
• /
• 제18권8호
• /
• pp.40-47
• /
• 2001

Optical measurement methods make it possible to detect object displacements with high resolution and noncontact measurements. Also, they are very robust against EMI noises and have long operation range. An optical triangulation sensor is one of widely used displacement measurement sensors for its sub-micron resolution, fast response, simple structure, and low cost. However. there are several errors caused by inclinations of a surface. speckle effects, power fluctuations of light sources, and noises of detectors. In this paper, in order to minimize error effects, we performed error analysis and proposed a new structure. Then, we setup a new modeling method and verify it through simulations and experiments. Based on the new model. we propose a new sensor structure and establish design criteria. Finally, we design a signal processing system to overcome a resolution-limited problem of light detectors. The resolution of the proposed system is 0.2${\mu}{\textrm}{m}$ in 5mm operating range.