• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.3
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• pp.183-190
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• 2007

To make use of surveying data obtained from different sensors and different techniques, it is a pre-requite step that register them in a common coordinate system. For this purpose, we developed methodologies to register IKONOS-2 Satellite Imagery using LiDAR(Light Detection And Ranging) data. To achieve this, conjugate features from these data should be extracted in advance. In this study, linear features are chosen as conjugate features. Then, to register them, observation equations are established from similarity measurements of the extracted features and the results was evaluated statistically. The results clearly demonstrate that the proposed algorithms are appropriate to register these data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1104-1110
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• 2009

3D A/V services are expected to be a representative service of next generation because it can give more realistic feeling by providing dimensions to the 2D images. In terms of transmission part of 3D A/V systems, however, it is difficult to provide these services on real-time in the wireless OFDMA networks because it has to send large amount of traffic. To address this, we proposed a novel scheduling algorithm which separates a 3D traffic into base layer and enhancement layer, and provides different priority to them. From simulation results, we can show that the proposed algorithm can improve QoS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1207-1212
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• 2015

In this paper, we propose three-dimensional (3D) visualization and recognition techniques of micro-objects under photon-starved conditions using photon counting integral imaging microscopy. To capture high resolution 2D images with different perspectives in the proposed method, we use Synthetic Aperture Integral Imaging (SAII). Poisson distribution which is mathematical model of photon counting imaging system is used to extract photons from the images. To estimate 3D images with 2D photon counting images, the statistical estimation is used. Therefore, 3D images can be obtained and visualized without any damage under photon-starved conditions. In addition, 3D object recognition can be implemented using nonlinear correlation filters. To prove the usefulness of our technique, we implemented the optical experiment.

• Journal of the Korea Computer Graphics Society
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• v.28 no.2
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• pp.11-19
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• 2022

Recently, various researches on medical image generation have been suggested, and it becomes crucial to accurately evaluate the quality and diversity of the generated medical images. For this purpose, the expert's visual turing test, feature distribution visualization, and quantitative evaluation through IS and FID are evaluated. However, there are few methods for quantitatively evaluating medical images in terms of fidelity and diversity. In this paper, images are generated by learning a chest CT dataset of non-small cell lung cancer patients through DCGAN and PGGAN generative models, and the performance of the two generative models are evaluated in terms of fidelity and diversity. The performance is quantitatively evaluated through IS and FID, which are one-dimensional score-based evaluation methods, and Precision and Recall, Improved Precision and Recall, which are two-dimensional score-based evaluation methods, and the characteristics and limitations of each evaluation method are also analyzed in medical imaging.

• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.165-175
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• 1996

In this paper, the image segmentation method based on the hierarchical pyramid image structure of reduced resolution versions of the image for solving the problems in the conventional methods is presented. This method is described the object detection and delineation by statistical approach. In the object detection method, IFSVR( Inverse-father-son variance ratio) method and FSVR(father-son variance ratio ) method are proposed for solving clustering validity problem occurred In the hierarchical pyramid image structure. An optimal object pixel Is detected at some level by this method. In the object delineation method, the iterative algorithm by top-down traversing method is proposed for moving the optimal object pixel to levels of higher resolution. Using the computer simulation, the results by the proposed statistical methods and object traversing method are investigated for the binary Image and the real image. At the results of computer simulation, the proposed methods of image segmentation based on the hierarchical pyramid Image structure seem to have useful properties and deserve consideration as a possible alternative to existing methods of image segmentation. The computation for the proposed method is required 0(log n) for n${\times}$n input image.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.31-34
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• 2009

본 연구에서는 KOMPSAT-3급 고해상도 위성영상을 이용하여 전처리 후 정밀 농업 주제정보를 추출하는 방법론을 제시하고자 하였다. 분석에 사용한 KOMPSAT-3급 고해상도 위성영상은 IKONOS (2001/5/25, 2001/12/25, 2003/10/23) 3개의 영상, QuickBird (2006/5/1, 2004/11/17) 2개의 영상, KOMPSAT-2 (2007/9/17) 1개의 영상 등 모두 6개의 영상을 확보 및 각각에 대한 현장 GCP자료 및 RPC, RPB 자료를 수집하여 정사보정을 실시하였다. RMSE는 약 $0.12\sim3.18$의 값으로 분포되었다. KOMPSAT근 급 영상자료로 부터 정밀농업물재배지도를 작성하기 위해 각 벤드별 Scatter기법을 이용하여 각 밴드간의 상간관계를 살펴보고, 3개의 최적의 밴드를 선정하였다. 또한 작물별 최적의 밴드 결정을 위해 각 밴드별 픽셀 값을 사용하여 Texture 분석을 실시하였다. 그 결과 논의 경우 모든 밴드에서 분석이 용이 한 것으로 분석되었으며, 4밴드의 경우 3개의 작물(고추, 옥수수, 벼)의 분석시 매우 적합한 밴드인 것으로 분석되었다. 각 영상별 필터링 기법과, ISODATA 방법을 이용한 정밀농업 토지이용도 작성하여 기존 스크린 디지타이징 기법으로 작성한 정밀토지이용도와 비교하였다. 다양한 식생정보를 추출하는 위하여 확보된 영상자료로부터 RVI, NDVI, ARVI, SAVI 식생지수 를 추출하였으며, 그 결과를 현장자료로부터 추출한 식생지수간의 결과 값과 비교분석하였다.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.655-664
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• 2020

Free viewpoint image synthesis technology is one of the important technologies in the MPEG-I (Immersive) standard. RVS (Reference View Synthesizer) developed by MPEG-I and in use in MPEG group is a DIBR (Depth Information-Based Rendering) program that generates an image at a virtual (intermediate) viewpoint from multiple viewpoints' inputs. RVS uses the mesh surface method based on computer graphics, and outperforms the pixel-based ones by 2.5dB or more compared to the previous pixel method. Even though its OpenGL version provides 10 times speed up over the non OpenGL based one, it still shows a non-real-time processing speed, i.e., 0.75 fps on the two 2k resolution input images. In this paper, we analyze the internal of RVS implementation and modify its structure, achieving 34 times speed up, therefore, real-time performance (22-26 fps), through the 3 key improvements: 1) the reuse of OpenGL buffers and texture objects 2) the parallelization of file I/O and OpenGL execution 3) the parallelization of GPU shader program and buffer transfer.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.179.2-179.2
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• 2012

과학기술위성 3호는 우리 은하계의 근적외선 관측, 우주 배경복사 관측 및 지구 지표면의 적외선 영상 획득을 임무로 하는 우주관측용 적외선카메라와 지구 지표면의 적외선 영상획득을 임무로 하는 지구관측용 적외선카메라 그리고 한반도 지역의 다중 스펙트럼 영상을 획득함으로써 대기관측 및 환경감시의 임무를 가지는 소형분광영상카메라를 장착한 우주 및 지구과학 연구용 위성이다. 2007년 개발을 시작하여 시험인증모델(EQM, Engineering& Qualification Model) 개발과 열구조모델 (STM, Structure and Thermal Model)을 개발 완료하였고, 2012년 하반기에 발사를 앞두고 2010년 비행모델 유닛들이 납품되기 시작하여 위성체 시스템 레벨에서의 조립 및 시험을 진행하고 있다. 본 논문에서는 조립 및 기능시험 중 발견된 유닛의 문제들을 해결 과정과 시스템 레벨에서의 전기접합시험, 극성시험, 비행소프트웨어 기능시험, 종합기능시험 및 ETE 시험등 기능 시험의 종류, 목적 그리고 검증 결과를 발표하고자 한다.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.41-49
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• 2011

Recently, the infrastructure of stereoscopy is growing fast. Though, the stereoscopy producing capacity is insufficient to meet the demand of the market. Because, at the moment most people who produce the stereoscopy are skilled for the two-dimensional images. So the characteristics of the human stereopsis and stereoscopic cameras are not well considered, it occurs many problems to the viewer. According to this, we studied about the optical axis distance adjustment of stereoscopic camera considering size perception in human stereopsis. First, we measured the area of the object in the image which depends on the optical axis distance. Second, based on the output of first experiment, we conducted a survey and figured out that if we keep the optical axis distance between 3.9cm to 130cm, it wouldn't occur any size perception and will be possible to produce high quality stereoscopy.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.28-28
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• 2022

본 연구는 용담댐유역을 포함한 금강 유역 상류 지역을 대상으로 Sentinel-1 SAR (Synthetic Aperture Radar) 위성영상을 기반으로 한 토양수분 산정을 목적으로 하였다. Sentinel-1 영상은 2019년에 대해 12일 간격으로 수집하였고, 영상의 전처리는 SNAP (SentiNel Application Platform)을 활용하여 기하 보정, 방사 보정 및 Speckle 보정을 수행하여 VH (Vertical transmit-Horizontal receive) 및 VV (Vertical transmit-Vertical receive) 편파 후방산란계수로 변환하였다. 토양수분 산정에는 Water Cloud Model (WCM)이 활용되었으며, 모형의 식생 서술자(Vegetation descriptor)는 RVI (Radar Vegetation Index)와 NDVI (Normalized Difference Vegetation Index)를 활용하였다. RVI는 Sentinel-1 영상의 VH 및 VV 편파자료를 이용해 산정하였으며, NDVI는 동기간에 대해 10일 간격으로 수집된 Sentinel-2 MSI (MultiSpectral Instrument) 위성영상을 활용하여 산정하였다. WCM의 검정 및 보정은 한국수자원공사에서 제공하는 10 cm 깊이의 TDR (Time Domain Reflectometry) 센서에서 실측된 6개 지점의 토양수분 자료를 수집하여 수행하였으며, 매개변수의 최적화는 비선형 최소제곱(Non-linear least square) 및 PSO (Particle Swarm Optimization) 알고리즘을 활용하였다. WCM을 통해 산정된 토양수분은 피어슨 상관계수(Pearson's correlation coefficient)와 평균제곱근오차(Root mean square error)를 활용하여 검증을 수행할 예정이다.