• 대한전자공학회논문지SP
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• 제46권3호
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• pp.1-9
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• 2009

투과전자현미경(transmission electron microscopy)에서 특정 투사각에서 획득한 2차원으로의 투사 영상의 열을 사용하여 세포와 같은 물질의 3차원 구조를 복원한다. 이때 전처리 과정으로 2차원 투사 영상의 정확한 영상 정렬과 밝기 보정이 필요하다. 본 논문에서는 기준점(fiducial marker)을 사용한 정렬 방법을 이용하여 영상열을 정렬하고, 수십 장의 영상들의 상이한 밝기 특성을 일정하게 보정하는 방법을 제시하였다. 영상의 투과율 모델에 근거하여, 영상의 주변부의 밝기 정보를 사용하여 각 영상의 조명을 일정한 값으로 조정하고 투사각에 따라 대상의 밝기가 일정하게 변동하도록 밝기 보정을 수행하는 알고리듬을 제시하였으며, 실제 투과전자현미경으로부터 얻은 영상열을 사용하여 밝기 보정 알고리듬의 성능을 검증하였다.

• 한국항행학회논문지
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• 제24권2호
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• pp.148-154
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• 2020

주름은 피부의 노화도를 알 수 있는 주요한 특징 중의 하나이다. 기존의 영상처리기반 주름검출은 다양한 피부 영상에 효과적으로 대처하기 어렵다. 특히, 주름이 선명하지 않고 주변 피부와 유사한 경우 주름추출 성능은 급격히 떨어진다. 본 논문에서는 현미경 피부 영상에서 주름추출을 위해 딥러닝을 적용한다. 일반적으로 현미경 영상은 광각렌즈를 탑재하므로 영상 가장자리 영역의 밝기가 어둡다. 본 논문에서는 이를 해결하기 위해 피부 영상의 밝기를 추정하여 보정 한다. 또한, 주름추출에 적합한 의미분할 네트워크의 구조를 적용한다. 제안방법은 연구실에서 수집한 피부 영상에 대한 테스트 실험에서 99.6%의 정확도를 획득하였다.

• KIEAE Journal
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• 제3권2호
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• pp.45-50
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• 2003

Today, there are increasing evidences that daylight is essential for health, well-being and productivity. One of the strong contributions, which atria can make to advantages in building, is in allowing the use of daylight. This research is to develop nomographs and to evaluate the daylight performances of toplit atria with louvers. For this purpose, the evaluation models of toplit atria with well indexes of 0.5, 1.0 or 2.0 have been selected through the field surveys of atrium buildings in Seoul area. Also, weather data for solar irradiance and luminous efficacy were gathered from the recently conducted previous researches. The computer simulations were performed under clear sky conditions, using the ADELINE program, and various daylight performances were analyzed by the daylight illumination ratio. Analyzing the simulation results, solar altitude, solar azimuth, and louver angle and louver reflectance were found to be important factors affecting the daylight performance of toplit atria. Using these variables, regression equations have been formulated, and the nomographs, which may predict the daylight performances of toplit atria with louvers, were developed. The developed nomographs were validated through comparing the results of nomograph predictions to the results of scale-model experiments.

• 한국광학회지
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• 제15권2호
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• pp.158-170
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• 2004

유선 통신의 포화지역이나 도심에서 벗어난 인구밀도가 낮은 지역 둥에서 고속 광통신을 위해 최근 무선 광통신이 새롭게 기대되고 있다. 본 논문에서는 이러한 무선 광통신을 위한 송신 광학계를 설계하였는데, 광원으로는 수평(7$^{\circ}$)및 수직(18$^{\circ}$) 발산각이 다른 비대칭 타원형 빔을 발산하는 레이저 다이오드(중심 파장 830 nm)를 사용하였다. 제안되는 송신 광학계는 장거리 전송(500 m∼1500 m)이 가능하고, 장거리 전송 후 수신단에서 빔 직경(3 m) 및 에너지 분포가 대칭형이 되도록 설계되었다. 이를 위해 비결상 광학계인 송신 광학계의 평가법으로 에너지 전달 효율과 복사 조도 분포를 계산하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.735-739
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• 2005

This paper presents a new system to estimate the head pose of human in interactive indoor environment that has dynamic illumination change and large working space. The main idea of this system is to suggest a new morphological feature for estimating head angle from stereo disparity map. When a disparity map is obtained from stereo camera, the matching confidence value can be derived by measurements of correlation of the stereo images. Applying a threshold to the confidence value, we also obtain the specific morphology of the disparity map. Therefore, we can obtain the morphological shape of disparity map. Through the analysis of this morphological property, the head pose can be estimated. It is simple and fast algorithm in comparison with other algorithm which apply facial template, 2D, 3D models and optical flow method. Our system can automatically segment and estimate head pose in a wide range of head motion without manual initialization like other optical flow system. As the result of experiments, we obtained the reliable head orientation data under the real-time performance.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.328-336
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• 2012

In this paper, we propose a robust fingertip extraction and extended Continuously Adaptive Mean Shift (CAMSHIFT) based robust hand gesture recognition for natural human-like HRI (Human-Robot Interaction). Firstly, for efficient and rapid hand detection, the hand candidate regions are segmented by the combination with robust $YC_bC_r$ skin color model and haar-like features based adaboost. Using the extracted hand candidate regions, we estimate the palm region and fingertip position from distance transformation based voting and geometrical feature of hands. From the hand orientation and palm center position, we find the optimal fingertip position and its orientation. Then using extended CAMSHIFT, we reliably track the 2D hand gesture trajectory with extracted fingertip. Finally, we applied the conditional density propagation (CONDENSATION) to recognize the pre-defined temporal motion trajectories. Experimental results show that the proposed algorithm not only rapidly extracts the hand region with accurately extracted fingertip and its angle but also robustly tracks the hand under different illumination, size and rotation conditions. Using these results, we successfully recognize the multiple hand gestures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2075-2092
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• 2017

Person re-identification is to match pedestrians observed from non-overlapping camera views. It has important applications in video surveillance such as person retrieval, person tracking, and activity analysis. However, it is a very challenging problem due to illumination, pose and viewpoint variations between non-overlapping camera views. In this work, we propose a viewpoint invariant method for matching pedestrian images using orientation of pedestrian. First, the proposed method divides a pedestrian image into patches and assigns angle to a patch using the orientation of the pedestrian under the assumption that a person body has the cylindrical shape. The difference between angles are then used to compute the similarity between patches. We applied the proposed method to real-time global multi-object tracking across multiple disjoint cameras with non-overlapping field of views. Re-identification algorithm makes global trajectories by connecting local trajectories obtained by different local trackers. The effectiveness of the viewpoint invariant method for person re-identification was validated on the VIPeR dataset. In addition, we demonstrated the effectiveness of the proposed approach for the inter-camera multiple object tracking on the MCT dataset with ground truth data for local tracking.

• 소성∙가공
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• 제14권3호
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• pp.245-250
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• 2005

Recently, micro machining technology for high precision mold becomes more interested for mass production of high performance optical parts micro-grooved on the surface, which is under very active development due to its effectiveness in the view point of optical performance. Mechanical micro machining technology now has more competitiveness on lithography, MEMS or LIGA processes which have some problems to fabricate especially cylinder type of groove in such as lenticular lens for illumination angle modulation system. In this study. a lenticular lens mold with U-type micro groove is fabricated making utilizing of the benefit of the mechanical micro machining technology. A shaping machining process is adapted using 3 axis degree of freedom micro machining system and single crystal natural diamond tool. A brass and a electroless nickel materials are used for mold fabrication. Machining force, chip shape and machined surface are investigated from the experiment and an optimal machining condition is found based on the examined problems from the micro cutting process.

• Journal of Korean Neurosurgical Society
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• 제60권3호
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• pp.275-281
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• 2017

Treating diseases in the field of neurosurgery has progressed concomitantly with technical advances. Here, as a surgical armamentarium for the treatment of cerebral aneurysms, the history and present status of the keyhole approach and the use of neuroendoscopy are reviewed, including our clinical data. The major significance of keyhole approach is to expose an essential space toward a target, and to minimize brain exposure and retraction. Among several kinds of keyhole approaches, representative keyhole approaches for anterior circulation aneurysms include superciliary and lateral supraorbital, frontolateral, mini-pterional and mini-interhemispheric approaches. Because only a fixed and limited approach angle toward a target is permitted via the keyhole, however, specialized surgical devices and preoperative planning are very important. Neuroendoscopy has helped to widen the indications of keyhole approaches because it can supply illumination and visualization of structures beyond the straight line of microscopic view. In addition, endoscopic indocyanine green fluorescence angiography is useful to detect and correct any compromise of the perforators and parent arteries, and incomplete clipping. The authors think that keyhole approach and neuroendoscopy are just an intermediate step and robotic neurosurgery would be realized in the near future.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2012년도 추계학술대회
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• pp.256-258
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• 2012

최근 LED를 이용한 IT 기술이 많은 관심을 받고 있으며, 특히 무인시설물에서는 효율적으로 LED를 관리해야하기 때문에 통신 및 조명 제어기술에 대한 연구가 활발히 진행 중에 있다. 그러나 LED 특성상 FOI(Filed of Illumination)의 제약이 따르기 때문에 서비스의 범위와 커버리지가 제한적이라는 한계를 가지며, LED 제어의 경우 최근 스마트단말을 이용한 기술이 많이 보급되고 있으나 수많은 스마트단말의 OS 플랫폼에 종속적으로 프로그램을해야만 하는 번거로움이 있기 때문에 개발 비용적인 측면에서도 매우 비효율적이다. 따라서 본 논문에서는 LED 기반 IT기술의 서비스 이용범위를 유연하게 넓힐 수 있는 LED 지향각의 원격제어 기술을 제안하고, 단말환경에 독립적으로 효과적인 LED제어를 가능하게 하는 차세대 웹표준인 HTML5(Hypertext Mark-up Language 5)기반의 시스템을 제안하였으며, 제안 기술의 핵심 프로그램을 제시하고 시뮬레이션을 수행함으로써 유용성을 입증하였다.