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스마트폰 카메라에서 다중 영상을 이용한 영상 잡음 제거 알고리즘
김성운,Kim, Sung-Un 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.10
본 연구에서는 동일한 환경에서 스마트폰 카메라에서 촬영한 여러 장의 영상들로부터 얻을 수 있는 정보를 활용하여 영상 잡음을 효과적으로 제거할 수 있는 알고리즘을 개발한다. 이를 위해 스마트폰의 제한된 연산능력에 맞는 다중 영상 정합(registration) 알고리즘을 개발하고, 다중 영상들의 정보들을 조합하여 효과적으로 영상 잡음을 제거하는 방법을 제시한다. 제시한 알고리즘을 정량적으로 잡음 제거 성능을 측정하기 위해 PSNR 값으로 비교 시 단일 영상을 이용할 때보다 훨씬 향상된 PSNR 값 향상을 가져왔다. 실제 안드로이드 스마트폰에 해당 알고리즘을 개발하여, 실제 사용 가능한 수준의 영상 처리 속도로 만족할만한 잡음 제거 효과를 얻을 수 있음을 확인하였다. In this study we propose an image denoising algorithm which manipulates the information obtained from multiple images in the same environment for mobile smart phones. We also envisage a multiple images registration method for mobile smart phone cameras equipped with limited computing ability and present an effective image denoising algorithm combining and manipulating the information obtained from multiple images. We proved that the proposed algorithm has much better PSNR value than the method applying single image. We verified that the propose approach has good denoising quality and can be utilized in the feasible level speed on Android smart phones.
차량 충돌 방지용 24㎓ 레이더 주파수대의 근거리 전파손실특성
하덕호(Deock-Ho Ha),류지열(Jee-Youl Ryu),김성운(Sung-Un Kim),최연욱(Yeon-Wook Choi) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.8
In this paper, we describe the short range propagation loss characteristic of 24㎓ frequency band used for automotive collision avoidance radar (ACAR). To investigate the radio propagation characteristic of ACAR signals, we used 24㎓ UMCW (Un-Modulated Continuous Wave) signals using by several polarized antenna combinations. To detect the accurate message data for safety guiding ACAR, we analyze and investigate the optimum receiving condition from the short range UMCW signal of the 24㎓ frequency. From the measurement analysis, it can be clearly seen that the short range UMCW signal can be encountered to multipath interference due to scattering rays from the ground plane and adjacent moving obstacles. In addition, it was also found that the received signal strength of circularly co-polarized antenna shows the most strong envelopes and best fading reduction effect.
수중 센서네트워크를 위한 에너지 효율적인 라우팅 방법 연구
김성운(Sung-Un Kim),박선영(Seon-Yeong Park) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.9
Underwater wireless sensor networks (UWSN) need efficient routing methods due to environmental characteristics such as limited communication bandwidth, various propagation delays and so on. In this paper, we propose an energy efficient hybrid routing method which is based on the honeycomb array of hexagonal prisms for the three-dimensional UWSN applications consisting of moving sensor nodes anchored on the bottom of the ocean. Our simulation results show that the proposed method reduces approximately 56% in the aspects of the energy consumption compared to the existing multi-hop methods.
표면 미세가공에서 Al 전극 및 Al 미세 구조물 제작을 위한 습식 식각 공정
김성운(Sung Un Kim),백승준(Seung Joon Paik),이승기(Seung Kim Lee),조동일(Dong Il Cho) 한국센서학회 2000 센서학회지 Vol.9 No.3
N/A Aluminum metal process in surface micromachining enables to fabricate Al electrodes or Al structures, which improve electrical characteristics by reducing contact- and line-resistance or makes the whole process to be simple by using oxide as sacrificial layer, However, it is not possible to use conventional sacrificial layer etching process, because HF solution attacks aluminum as well as sacrificial oxide. The mixed solution of BHF and glycerine as an alternative shows the adequate properties to meet with this end. The exact etching properties, however, are sensitively depends on the geometry of the released structure, because the most etching process of sacrificial layer proceeds to the lateral direction in narrow space. Also, the surface roughness of aluminum affects to the etching characteristics. This paper reports experimental results on the effect of microstructure and surface roughness of aluminum to the etching properties. Considering these effects, we propose the optimized etching condition, which can be used practically for the fabrication of aluminum electrodes and microstructures by using standard surface micromachining process without modification or additional process.
김성운(Sung-Un Kim),박선영(Seon-Yeong Park) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.3
In order to provide real-time USN (Ubiquitous Sensor Network) services, the BcN(Broadband convergence Network) backbone networks connecting wireless sensor network sink node to server must be equipped with DWDM (Dense-Wavelength Division Multiplexing) based transmission networks. One of the critical issues in DWDM transport networks is the problem of routing and assigning wavelengths which plays a key role in improving the efficiency for transmission capacity utilization. This paper proposes a new routing algorithm called MW-PMIPR (Multi Wavelength-Priority Minimum Interference Path Routing) which improves wavelength utilization by choosing route between wireless sensor network sink nodes to server, that does not interfere too much with potential future unicast connection requests. The MW-PMIPR increases the wavelength utilization by avoiding congestion in future unicast session requests. We measured the performance of the proposed algorithm in terms of the resource utilization. The simulation results demonstrate that the MW-PMIPR algorithm is superior to the previous unicast routing algorithms.
김성운(Sung-Un Kim) 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.5
본 연구에서는 스마트폰의 제한된 연산 환경에 적합한 영상 잡음 제거 알고리즘을 개발하여 기존의 연구들과 비교할 시에 스마트폰에서 보다 빠르게 영상 후처리 결과물을 얻고, 품질적인 면에서도 비교할 만한 수준의 영상을 얻는 앱 환경에서 실용적인 알고리즘을 제안한다. 제안된 저조도 환경에서 스마트폰 카메라를 위한 영상잡음 제거 알고리즘은 영상획득 과정에서 발생한 가우시안 잡음만 찾아내어 제거함으로써 영상 복원과정에서 발생하는 연산량을 감축하면서 윤곽선의 블러링 현상을 방지한다. 실험 결과에 의하면 기존의 평균필터와 메디언 필터 적용 기법들에 비해 훨씬 양호한 PSNR 값을 가짐을 보였다. 그리고 영상 내 윤곽선의 흐려짐을 방지하여 기존의 방법들에 의한 결과들보다 선명한 영상 품질을 가지며, 또한 기존의 라플라시안 마스크연산적용에 비해 연산량을 약 52% 감소시킴으로서 안드로이드 기반의 스마트폰 카메라 앱으로 구현 및 적용 했을 때도 복원된 영상이 원 영상에 훨씬 근접하는 영상복원 성능을 가짐을 확인하였다. In this study we propose an image denoising algorithm appropriate for mobile smart phone equipped with limited computing ability, which has better performance and at the same time comparable quality comparing with previous studies. The proposed image denoising algorithm for mobile smart phone cameras in low level light environment reduces computational complexity and also prevents edge smoothing by extracting just Gaussian noises from the noisy input image. According to the experiment result, we verified that our algorithm has much better PSNR value than methods applying mean filter or median filter. Also the result image from our algorithm has better clear quality since it preserves edges while smoothing input image. Moreover, the suggested algorithm reduces computational complexity about 52% compared to the method applying original Laplacian mask computation, and we verified that our algorithm has good denoising quality by implementing the algorithm in Android smart phone.