• 한국항공우주학회지
• /
• 제34권5호
• /
• pp.81-87
• /
• 2006

본 논문에서는 전투기 조종석과 같은 제한된 공간에서 사용 가능한 광학 방식의 헤드 트랙커 시스템을 설계하고 그 성능을 시험하였다. 이 시스템은 다른 빛의 간섭을 차단하기 위해 적외선 발광다이오드와 두 대의 적외선 CCD 카메라를 사용하였다. 그리고 광학 방식의 헤드 트랙커 알고리즘은 특징점 추출 알고리즘과 3차원 움직임 추정 알고리즘으로 구성하였다. 카메라 이미지 평면 위에서 특징점의 2차원 위치 좌표를 획득하기 위한 특징점 추출 알고리즘은 디지털 영상 처리 기술인 문턱치 (thresholding)와 마스킹 (masking) 기법을 사용하였다. 특징점의 위치 변화로부터 조종사의 머리 움직임을 추정하는 3차원 움직임 추정 알고리즘은 확장 칼만 필터 (EKF)를 사용하였다. 또한, 정밀한 레이트 테이블을 사용하여 시스템 성능을 검증하고 회전 성능에 대해 관성 센서와 비교하였다.

• International Journal of Aeronautical and Space Sciences
• /
• 제18권4호
• /
• pp.757-766
• /
• 2017

For implementing the proportional navigation guidance law on passive homing missiles equipped with strapdown imaging infrared seekers, the line-of-sight angles and rates with respect to the inertial frame should be estimated by carefully handling the parasitic instability effect due to the seeker's latency. By introducing a new state vector representation along with the Pade approximation for compensating the time-delay of the seeker, this paper proposes a new guidance filter structure, stochastic dynamic models and measurement equations, in three-dimensional homing problem. Then, it derives the line-of-sight angle and rate estimator in general two-dimensional engagement by applying the extended Kalman filter to the proposed structure. The estimation performance and the characteristics of the proposed filter were evaluated via a series of numerical experiments.

• 한국군사과학기술학회지
• /
• 제14권4호
• /
• pp.676-683
• /
• 2011

In this paper, we propose a robust method which can detect and track a high-speed small approaching target in a cluttered environment for Korean Active Protection System. The proposed method uses a temporal and spatial filter, tracking filter to detect and track a single target in consecutive order. And it is comprised of a candidate target detection step, a prior target selection step and a target tracking. Field tests on real infrared image sequences show that the proposed method could stably track a high speed and small target in complex background and target occlusion.

• 전기학회논문지P
• /
• 제57권4호
• /
• pp.400-403
• /
• 2008

In this work, an individual trespassing detector using a PIR sensor to detect infrared rays only between the range of $9.4{\sim}10.4{\mu}m$ radiated from the body is proposed. This detector using FIR sensor detects not insect or object but human body, It doesn't restrict the inhabitant's behavior because the filter of pm sensor is designed to have face angle and the detector only detects the window area. The existing wide angle filter, RIR sensor, detects $30^{\circ}$ angle while the face angle filter sensor on this paper detects $11^{\circ}$ angle with 3cm of face angle filter from 2m of detecting distance. In case of interruption of electric power, 250mAh of lithium-ion battery has worked for 10 hours consuming 22mA in normal state. Meanwhile, in case of interruption of electric power, 250mAh of battery has worked for 4 hours consuming 60mA in trespassing detecting state. Projector, receptor, controller and alarm are put on one PCB in order to make it convenient to install without any special installation skill.

• 대한전자공학회논문지SP
• /
• 제42권6호
• /
• pp.83-88
• /
• 2005

본 논문에서는 적외선 영상의 단측형 충격잡음 제거를 위해, 비선형 위치 추정기를 근간으로 하는 충격잡음 검출기를 설계하여 단측형 충격잡음을 검출하고, 검출된 정보를 기반으로 국부윈도우 크기를 적응적으로 가변시켜 중앙값 필터링을 수행하는 비선형 필터를 제안하였다. 가시광 영상에 대해 성능이 입증된 기존 12종 필터와 성능비교를 수행하였다. 정성적 측면에선 제안된 필터가 잡음오염이 과다한 $20\%$ 수준까지도 충분한 잡음제거 성능과 함께 영상의 세부정보를 잘 보존하는 것을 확인할 수 있었다. 정량적 측면에선 PSNR을 측정 비교하였는데, 영상 세부 정보 보존이 우수한 중앙값 필터($3{\times}3$) 보다 13-31[dB] 더 개선된 성능을 얻었으며, 잡음제거 특성이 우수한 중앙값 필터($5{\times}5$) 보다는 18 - 25[dB] 더 개선된 잡음제거 성능을 보였다.

• Korean Chemical Engineering Research
• /
• 제46권2호
• /
• pp.397-401
• /
• 2008

레이저 애블레이션에 의해서 가지상 구조체 형상인 나노입자 응집체를 합성하였다. 기존 마이크론 금속섬유 필터의 표면상에 나노입자 응집체를 고착하여 여과성능을 향상시켰다. 에어로졸 상에서 소결 처리된 나노입자 응집체를 증착한 후 열처리를 하여 나노구조체가 표면상에 형성된 소결 처리된 나노입자 응집체 고착 필터를 제작하였다. 소결 온도가 증가할수록 마이크론 금속섬유 필터 표면상에 고착된 나노입자 응집체의 표면적 증가로 인하여 차압은 조금 증가하지만 여과효율은 현저하게 증가하였다.

• 한국산업보건학회지
• /
• 제15권1호
• /
• pp.1-7
• /
• 2005

Although the Fourier Transform Infra-Red spectrophotometric Direct on Filter(FTIR-DOF) method is a useful analytical technique for quantifying quartz content in respirable dust samples, a number of analytical problems must be taken into consideration such as, to name only a few, inhomogeneous deposition of particles, level of environmental humidity, uneven surface of the filter, and interfering minerals in the sample. This study was designed to select the most suitable wavelength and proper filter material for the method, and to investigate effects of humidity and inhomogeneous deposition of particles on the filter. Samples of respirable dust, created in a dust chamber containing standard material of quartz, were collected using a cyclone equipped with a 25mm filter as a collection medium. The results were as follows; 1. Among seven (7) commercially available filters tested for the FTIR-DOF method, the DM 800 filter showed the best analytical performance having the lowest background absorbance bands and no overlapping peaks at 799, 779, and $695cm^{-1}$. 2. The variations of absorbance due to humidity ranged from 1.0% to 3.3% for $799cm^{-1}$, 1.0% to 3.3% for $779cm^{-1}$, and 8.9%~20.9% for $695cm^{-1}$ peaks, respectively. The $699cm^{-1}$ peak was proved to be most vulnerble to environmental humidity for quantitative analysis of quartz. 3. As for effects of inhomogeneous deposition of samples, the highest variation of absorbance of 10.9% ($13.5{\mu}g$) was observed when using the 695cm-1. The variations of absorbance from the other two peaks, 799 and $779cm^{-1}$, ranged from 1.2 to 3.2%, and 1.4 to 4.1%, respectively. Therefore, the $799cm^{-1}$ peak was considered to be most reliable for quantitative analysis of quartz. The results of this study suggest that, for quantitative analysis of quartz in the respirable dust samples, use of the $799cm^{-1}$ peak can minimize the influence of environmental humidity and inhomogeneous deposition of particles on the filter. The FTIR-DOF method, if adopted for routine analysis of quartz in the respirable dust samples, could save sample preparation time and efforts substantially and also could increase analytical throughputs. Since use of the $799cm^{-1}$ peak is prone to be affected by interferences in the sample, further research on minimizing the effects is needed.

• 대한기계학회논문집A
• /
• 제32권8호
• /
• pp.617-623
• /
• 2008

The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 kPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%.

• 전자공학회논문지CI
• /
• 제46권4호
• /
• pp.102-110
• /
• 2009

본 논문은 적외선영상(infrared image)에서 배경모델링 기반의 실시간 객체 탐지 기법과 고속 PPC(PowerPC) & FPGA(Field Programmable Gate Array) 기반 개방형 구조의 하드웨어 설계 방법을 제안한다. 개방형 구조는 하드웨어 및 소프트웨어의 이식이 용이하고, 확장, 호환성, 관리 및 유지보수 등이 편리한 장점이 있다. 제안된 배경모델링 방법을 개방형 구조에 탑재하기 위하여 입력영상에서 검색영역 템플릿을 성긴 블록으로 구성하여 탐색영역의 크기를 줄인다. 또한, 이전 프레임과 현재 프레임에서 영상의 흔들림이 발생했을 때 보정하기 위해 전역움직임 보상방법을 적용한다. 배경과 객체를 분리는 픽셀 밝기의 시간 분석을 통해 적응적 값을 적용한다. 분리된 객체주변에 발생하는 클러터 제거 방법은 중앙값 필터를 적용한다. 설계된 임베디드 시스템에서 배경모델링, 객체탐지, 중앙값 필터, 라벨링, 합병 등의 방법은 PPC에서 구현하였다. 실험결과 제안된 임베디드 시스템에서 전역 움직임 보정과 배경예측을 통해 실시간으로 객체가 탐지될 수 있음을 보였다.

• 한국컴퓨터정보학회논문지
• /
• 제21권12호
• /
• pp.35-41
• /
• 2016

In this paper, we propose a new real-time dead pixel detection method based on spatial compare filtering, which are usually used in the small target detection. Actually, the soft dead and the small target are cast in the same mold. Our proposed method detect and remove the dead pixels as applying the spatial compare filtering, into the pixel outputs of a detector after the non-uniformity correction. Therefore, we proposed method can effectively detect and replace the dead pixels regardless of the non-uniformity correction performance. In infrared camera, there are usually many dead detector pixels which produce abnormal output caused by manufactural process or operational environment. There are two kind of dead pixel. one is hard dead pixel which electronically generate abnormal outputs and other is soft dead pixel which changed and generated abnormal outputs by the planning process. Infrared camera have to perform non-uniformity correction because of structural and material properties of infrared detector. The hard dead pixels whose offset values obtained by non-uniformity correction are much larger or smaller than the average can be detected easily as dead pixels. However, some dead pixels(soft dead pixel) can remain, because of the difficulty of uncleared decision whether normal pixel or abnormal pixel.