• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1081-1083
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• 2003

The CC's main objective is to manage and control the various operation of the MSC camera. The CC has capability to control the various camera operation modes such as INIT mode, WAIT mode, STANDBY mode, READY IMAGING, DEFAULT READY IMAGING, IBIT and IMAGING mode as well as to manage the interface of the PMU. This paper also shows not only the design concepts in the both of the hardware and the operational software, but also the implementation results for the various CC functions.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.46-49
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• 2005

In this paper, a novel 2D/3D convertible display system based on integral imaging is proposed. Combining two liquid crystal display panels with integral imaging, it is possible to convert the display between two-dimensional mode and three-dimensional mode without mechanical movement. The proposed method is proven by preliminary experiments.

• Journal of electromagnetic engineering and science
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• 제18권3호
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• pp.199-205
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• 2018

In this study, an imaging mode of the modified SweepSAR is proposed with performance analysis for a high-resolution and wide swath coverage. To reduce the overall antenna size required for the solution of the azimuth ambiguity problem, different pulse repetition frequencies (PRFs) are utilized for different transmitters, respectively. For each imaging mode, system performance parameters are used for simulation, analysis, wide swath prediction, and comparison between conventional ScanSAR mode and SweepSAR mode based on scanon-receive (SCORE). The system parameters of AASR, RASR, and NESZ will be estimated and suggested on the imaging mode by using appropriate reflector antenna with the effectiveness of a modified SweepSAR employing dual channels.

• Current Optics and Photonics
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• 제1권6호
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• pp.598-603
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• 2017

Traditional three-dimensional (3-D) laser imaging systems are based on real aperture imaging technology, whose resolution decreases as the range increases. In this paper, we develop a novel 3-D imaging technique based on the synthetic aperture technology in which the imaging resolution is significantly improved and does not degrade with the increase of the range. We consider an imaging laser radar (ladar) system using the floodlight transmitting mode and multi-beam receiving mode. High 3-D imaging resolutions are achieved by matched filtering the linear frequency modulated (LFM) signals respectively in range, synthetic aperture along-track, and the real aperture across-track. In this paper, a novel 3-D imaging signal model is given first. Because of the motion during the transmission of a sweep, the Doppler shift induced by the continuous motion is taken into account. And then, a proper algorithm for the 3-D imaging geometry is given. Finally, simulation results validate the effectiveness of the proposed technique.

• 한국정보통신학회논문지
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• 제13권2호
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• pp.369-375
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• 2009

본 논문에서는 완전 시차 배경 영상을 가지는 새로운 형태의 2D-3D 겸용 디스플레이 시스템을 제안한다. 제안하는 시스템의 집적 영상 시스템과 기존의 2D 평면 디스플레이 구성이 되며, 3D 모드와 2D 모드에서 구동이 가능하다. 3D 모드에서는 집적 영상 기술을 이용하여 배경영상을 만들어서 주요 영상과 결합함으로써 3D 영상을 만든다. 2D 모드에서는 집적영상 시스템이 2D 평면 디스플레이의 백라이트 역할을 수행하고 2D 평면 디스플레이에 2D 영상이 표시된다. 제안하는 방법의 유용함을 보이기 위해서 기초 실험을 수행하고 성공적인 실험 결과를 보고한다.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.687-698
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• 2012

LADAR systems can rapidly acquire 3D point clouds by sampling the target surfaces using laser pulses. Such point clouds are widely used for diverse applications such as DSM/DTM generation, forest biomass estimation, target detection, wire avoidance and so on. Many kinds of LADAR systems have been developed with their respective purposes and applications. Particularly, Geiger mode imaging LADAR systems are increasingly utilized since they are energy efficient thank to extremely sensitive detectors incorporated into the systems. The purpose of this research is the performance assessment of a Geiger mode imaging LADAR system based on simulation with the real system parameters. We thus developed a simulation method of such a LADAR system by modeling its geometric, radiometric, optic and electronic aspects. Based on the simulation, we performed the performance assessment of a newly designed system to derive the outlier ratio and false alarm rate expected during its operation in almost real environment with reasonable system parameters. The proposed simulation and performance assessment method will be effectively utilized for system design and optimization, and test data generation.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.571-574
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• 1997

fMRI, functional MRI introduced recently appears based on the gradient echo technique which is sensitive to the field inhomogeneity developed due to the local susceptibility changes of blood oxygenation and deoxygenation. Common to all the gradient echo techniques is that the signal due to the susceptibility effects is generally decreased with increasing inhomogeneity due to the $T2^*$ effect or conventionally known as blood oxygenation level dependent (BOLD) effect. It is, also found that the BOLD sensitivity is also dependent on the imaging modes, namely whether the imaging is in axial, or coronal or sagittal mode as well as the directions of the vessels against the main magnetic field. We have, therefore, launched a systematic study of imaging mode dependent signal change or BOLD sensitivity as well as the signal changes due to the tilting angle of the imaging planes. Study has been made or both TRFGE sequence and CGE sequence to compare the distinctions of the each mode since each technique has different sensitivity against susceptibility effect. Method of computation and both the computer simulations and their corresponding experimental results are presented.

• Investigative Magnetic Resonance Imaging
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• 제1권1호
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• pp.66-74
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• 1997

혈액의 산소화와 불 산소화에 따른 국부적인 자화율 효과의 변화에 의한 자장의 불 균일성에 민감한 경사 자장 에코 기법은 현재의 뇌기능 MR 영상의 기본이 되고 있다. 일반적으로 이러한 경사 자장 에코기법은 $T2^{*}$ 혹은 BOLD효과에 의한 자장의 불 균일성의 증가가 신호의 감소로 나타난다. BOLD 효과는 주자장에 대한 핏줄의 방향이나 영상 형식, 즉, 횡단면, 관상면, 또는 시상면에 따라 달라진다. 그래서 영상 형식과 영상면에 대한 기울임 각에 따른 신호의 변화와 BOLD 효과의 변화에 대한 정량적인 연구를 하였다. 연구는 자화율 효과에 대해 다른 민감도를 가지는 TRFGE 와 CGE 기법으로 이루어졌다. 컴퓨터 모의 실험과 실험 결과를 본 논문에 나타내었다.

• 대한원격탐사학회지
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• 제15권3호
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• pp.167-175
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• 1999

원격탐사 관련 핵심기술은 최근에 국방, 의료영상, 환경, 지질 등과 같은 광범위한 분야에서 활용범위를 확대하고 있다. 1cm ~ 수십 cm 파장의 파를 관측하는 마이크로파 원격탐사 기술은 반사 적외선 원격탐사나 열 적외선 원격탐사 기술에 비해 날씨조건과 밤낮에 관계없이 탐사를 수행할 수 있다는 장점을 가지고 있다. 마이크로파 영상레이다인 합성 개구 레이다를 이용한 영상화 방식은 응용목적에 따라 stripmap 방식, spotlight 방식, 그리고 inverse 방식으로 구분된다. 본 논문에서는 inverse 방식으로 지상에 고정된 레이다가 비행하는 항공체를 영상화하는 기법에 대해서 기술하였다. 비행 항공체의 영상화 기법은 자동 펴적인식 시스템 구축시 중요한 기술단계이며, 최근 이 분야에 대해 활발히 연구되고 있다. 비행 항공체를 영상화하기 위해 제안된 3가지 방식인 퓨리에 처리 기법, 시간-n 주파수 처리 기법, 그리고 투시로부터 복원 기법을 소개한 후, 각 방식의 장단점을 분석하였다.

• Journal of Korean Neurosurgical Society
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• 제64권6호
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• pp.933-943
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• 2021

Objective : Percutaneous pedicle screw (PPS) fixation is a needle based procedure that requires fluoroscopic image guidance. Consequently, radiation exposure is inevitable for patients, surgeons, and operation room staff. We hypothesize that reducing the production of radiation emission will result in reduced radiation exposure for everyone in the operation room. Research was performed to evaluate reduction of radiation exposure by modifying imaging manner and mode of radiation source. Methods : A total of 170 patients (680 screws) who underwent fusion surgery with PPS fixation from September 2019 to March 2020 were analyzed in this study. Personal dosimeters (Polimaster Ltd.) were worn at the collar outside a lead apron to measure radiation exposure. Patients were assigned to four groups based on imaging manner of fluoroscopy and radiation modification (pulse mode with reduced dose) : continuous use without radiation modification (group 1, n=34), intermittent use without radiation modification (group 2, n=54), continuous use with radiation modification (group 3, n=26), and intermittent use with radiation modification (group 4, n=56). Post hoc Tukey Honest significant difference test was used for individual comparisons of radiation exposure/screw and fluoroscopic time/screw. Results : The average radiation exposure/screw was 71.45±45.75 µSv/screw for group 1, 18.77±11.51 µSv/screw for group 2, 19.58±7.00 µSv/screw for group 3, and 4.26±2.89 µSv/screw for group 4. By changing imaging manner from continuous multiple shot to intermittent single shot, 73.7% radiation reduction was achieved in the no radiation modification groups (groups 1, 2), and 78.2% radiation reduction was achieved in the radiation modification groups (groups 3, 4). Radiation source modification from continuous mode with standard dose to pulse mode with reduced dose resulted in 72.6% radiation reduction in continuous imaging groups (groups 1, 3) and 77.3% radiation reduction in intermittent imaging groups (groups 2, 4). The average radiation exposure/screw was reduced 94.1% by changing imaging manner and modifying radiation source from continuous imaging with standard fluoroscopy setting (group 1) to intermittent imaging with modified fluoroscopy setting (group 4). A total of 680 screws were reviewed postoperatively, and 99.3% (675) were evaluated as pedicle breach grade 0 (<2 mm). Conclusion : The average radiation exposure/screw for a spinal surgeon can be reduced 94.1% by changing imaging manner and modifying radiation source from real-time imaging with standard dose to intermittent imaging with modified dose. These modifications can be instantly applied to any procedure using fluoroscopic guidance and may reduce the overall radiation exposure of spine surgeons.