Automatic illumination and color compensation using mean shift and sigma filter

Heechul Han,Kwanghoon Sohn IEEE 2009 IEEE transactions on consumer electronics Vol.55 No.3

<P>We present a novel framework for automatic illumination and color compensation algorithm using mean shift and the sigma filter (ICCMS) to restore distorted images taken under the arbitrary lighting conditions. The proposed method is effective for appropriate illumination compensation, vivid color restoration, artifacts suppression, automatic parameter estimation, and low computational cost for HW implementation. We show the efficiency of the mean shift filter and sigma filter for illumination compensation with small sized kernel while considering the processing time and removing the artifacts such as HALO and noise amplification. The proposed color restoration function can restore the natural color and correct color noise artifact more perceptually compared with conventional methods. For the automatic processing, the image statistics analysis estimates suitable parameter and all constants are pre-defined. We also introduce the ROI-based parameter estimation dealing with small shadow area against spacious well-exposed background in an image for the touch-screen camera. The object evaluation is performed by CMC, CIEde2000, PSNR, SSIM, and 3D CIELAB gamut with state-of-the-art research and existing commercial solutions.</P>

JND와 경계 보호 평탄화 필터를 이용한 휘도 및 색상 복원

한희철(Heechul Han),손광훈(Kwanhoon Sohn) 大韓電子工學會 2009 電子工學會論文誌-SP (Signal processing) Vol.46 No.6

본 논문에서는 임의의 조명 상황에서 왜곡된 영상을 JND(Just noticeable difference)와 경계 보호 평탄화 필터(edge-preserving smoothing filter) 를 사용하여 자동적으로 휘도 및 색상을 복원 하는 기법을 제안한다. 제안된 방법은 최적의 휘도 보상, 선명한 색상 복원, 휘도 보상 시 발생되는 여러 가지 문제점의 최소화, 자동화된 매개변수 추정 그리고 하드웨어 구현을 위한 고속화 등을 목적으로 하고 있다. 이를 위하여 본 논문에서는 후광효과(HALO)나 노이즈 증폭 등의 눈에 거슬리는 결함을 제거하기 위하여 경계 보호 평탄화 필터의 효용성에 대해 보인다. 또한 제안된 색상 복원 함수는 인간시각에 근거해 자연스러운 색상의 복원과 왜곡된 색상의 보정을 수행한다. 자동화된 처리를 위하여 영상의 통계적 분석과 JND를 이용해 적합한 매개변수를 찾으며 모든 상수는 미리 정의되어 사용된다. 또한 터치스크린 카메라를 이용한 관심영역(ROI : Region of Interest) 기반 매개변수 추정기법을 사용하여 역광 사진 보정을 좀 더 효율적으로 수행한다. 객관적 평가를 위해 CMC, CIEde2000, PSNR, SSIM, 그리고 3D CIELAB 색역을 기존의 연구나 상업 제품들과 비교하였다. We present the framework for JND based Illumination and Color Restoration Using Edge-preserving filter for restoring distorted images taken under the arbitrary lighting conditions. The proposed method is effective for appropriate illumination compensation, vivid color restoration, artifacts suppression, automatic parameter estimation, and low computation cost for HW implementation. We show the efficiency of the mean shift filter and sigma filter for illumination compensation with small spread parameter while considering the processing time and removing the artifacts such as HALO and noise amplification. The suggested CRF (color restoration filter) can restore the natural color and correct color distortion artifact more perceptually compared with current solutions. For the automatic processing, the image statistics analysis finds suitable parameter using JND and all constants are pre-defined. We also introduce the ROI-based parameter estimation dealing with small shadow area against spacious well-exposed background in an image for the touch-screen camera. The object evaluation is performed by CMC, CIEde2000, PSNR, SSIM, and 3D CIELAB gamut with state-of-the-art research and existing commercial solutions.

3차원 카메라를 위한 거리 대비를 이용한 입체감 정보 표시 방법

한희철(Heechul Han),최양림(Yanglim Choi),조재문(Jaemoon Jo) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

By employing the depth contrast detection algorithm, the 3d perception information display method for the 3D camera is proposed in this paper. We apply the stereo matching algorithm to the pre-defined contrast detection focus points for the real time operation. The depth contrast is obtained from the depth differences and the estimated real distance between the clusters of the points. The proposed method provides the useful information while taking a 3D picture for having a better 3D perception.

Text Mining Online-Crowdsourced Suggestions for Urban and Regional Planning

Heechul Kim(김희철),Sumi Han(한수미) 한국기술혁신학회 2020 기술혁신학회지 Vol.23 No.6

온라인 크라우드소싱 플랫폼을 통해 수집된 빅데이터를 활용한 텍스트마이닝은 최근 다양한 분야에서 빠르게 성장하고 있는 분석방법론이다. 이 연구는 온라인 정책제안 플랫폼인 광화문1번가에 수집된 데이터를 다양한 텍스트마이닝을 통하여 시민들이 제안한 의견 속에서 도시계획 정책 이슈를 도출하고 협력적계획의 상향식 접근법 측면에서 정책적 시사점을 제시하는 것을 주요 목적으로 한다. 이를 위해서 총 6,994개의 제안에서 명사만을 주요 분석대상으로 삼았으며, 키워드와 네트워크 분석을 수행하였다. 키워드 분석결과 시민들의 주요 고민은 주택, 토지, 교통 정책과 관련된 키워드로 나타났고, 연어 분석결과는 임대료와 도시개발과 같은 주택정책에 대한 내용을 확인할 수 있었다. 네트워크 분석을 통하여 정책이슈를 공유하는 지역커뮤니티를 도출하였고, 그 결과는 지리적으로 가깝거나 혹은 주요 이슈를 공유하는 특성을 보였다. 온라인 플랫폼을 통해 수집된 정책제안 데이터의 텍스트마이닝을 통해 도시민들의 주요고민을 키워드 중심의 이슈로 도출하고, 유사한 이슈를 공유하는 지역을 밝힘으로써 협력적계획과 의사결정과정에서의 활용가능성을 보였다는 점에서 연구의 의의가 있다. Text mining of big data generated through online crowdsourcing platforms has emerged as a rapidly growing field in research. In line with collaborative planning, this study took a bottom-up approach to examining people’s ideas about urban and regional planning: Text mining was used to analyze data crowdsourced from an online forum, Gwangwhamoon 1st Street, to identify Korean citizens’ policy suggestions. Noun words as the target dataset were extracted from 6,994 suggestions, and keyword and network analysis were conducted. The keyword analysis revealed that Koreans’ main concerns and interests related to housing, land, and transportation policies. The network analysis revealed co-occurring keywords, indicating common policy suggestions about housing policies. Networks of specific regions were also examined, resulting in ten communities grouped by physical distance or similar regional problems. The findings of this study can help experts and government officials identify the main concerns of residents in Korea and develop cooperative systems across municipalities, thereby improving policy-decision process in the fields of urban and regional planning.

A study of pin-to-plate type spark discharge generator for producing unagglomerated nanoaerosols

Han, Kyuhee,Kim, Woongsik,Yu, Jiwon,Lee, Jeonghoon,Lee, Heechul,Gyu Woo, Chang,Choi, Mansoo Elsevier 2012 Journal of aerosol science Vol.52 No.-

Intelligent task robot system based on process recipe extraction from product 3D modeling file

Hyonyoung Han,Heechul Bae,Hyunchul Kang,Jiyon Son,Hyun Kim 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

This study introduces intelligent task robot system based on process recipe extraction from standard 3D model files. In small quantity batch production and mixed flow manufacturing condition, lots of time is spent on process planning and device control such as path planning in a robot system. If these processes could be automated, mixed flow production of various products will be working efficiently. This paper suggests automated process recipe extraction module based product registration subsystem and visual servoing based intelligent assembly task robot subsystem. The recipe module extracts list of parts, each part size and position from standard 3D model file (STEP) and analyzes the structure of product between parts. The extracted product data is stored in the recipe knowledge base as a recipe format and also plan-view image of each part. Robot system consists of real-time part recognition module, part scheduling module and motion planner module. The part recognition module identifies parts by matching real-time RGB image and plan-view image in knowledge base. The part scheduling module plan the sequence of part for task using a decision tree method. The motion planner module controls assembly task robot according to process recipe depending on task type. Performance of the system was tested with five types of sample products.

High-Resolution, Parallel Patterning of Nanoparticles via an Ion-Induced Focusing Mask

You, Sukbeom,Han, Kyuhee,Kim, Hyoungchul,Lee, Heechul,Woo, Chang Gyu,Jeong, Changui,Nam, Woongsik,Choi, Mansoo WILEY-VCH Verlag 2010 Small Vol.6 No.19

<P>An ion-induced focusing mask under the simultaneous injection of ions and charged aerosols generates invisible electrostatic lenses around each opening, through which charged nanoparticles are convergently guided without depositing on the mask surface. The sizes of the created features become significantly smaller than those of the mask openings due to the focusing capability. It is not only demonstrated that material-independent nanoparticles including proteins can be patterned as an ordered array on any surface regardless of the conductive, nonconductive, or flexible nature of the substrate, but also that the array density can be increased. Highly sensitive gas sensors based on these focused nanoparticle patterns are fabricated via the concept.</P> <B>Graphic Abstract</B> <P>Material-independent nanoparticles including proteins can be patterned by ion-induced focusing to give an ordered array with reduced feature sizes on any surface regardless of the conductive, nonconductive, or flexible nature of the substrate. The array density can also be increased. Highly sensitive gas sensors based on nanoparticle patterns are fabricated. <img src='wiley_img_2010/16136810-2010-6-19-SMLL201000892-content.gif' alt='wiley_img_2010/16136810-2010-6-19-SMLL201000892-content'> </P>

재활용 재료가 적용된 유동성 채움재의 장기압축강도 평가

안희철(Ahn, Heechul),설영만(Seol, Young-Man),홍기권(Hong, Gigwon),박정준(Park, Jeong-Jun),한중근(Han, Jung-Geun),유승경(You, Seung-Kyong) 한국지반신소재학회 2021 한국토목섬유학회 학술발표회 Vol.2021 No.3

Fast Auto-focus Control Algorithm Using the VCM Hysteresis Compensation in the Mobile Phone Camera

Taekyu Kim,Heechul Hwang,Chanho Han,Dukgyoo Kim 대한전자공학회 2005 ITC-CSCC :International Technical Conference on Ci Vol.2005 No.1

공동이 발생된 지반의 비파괴심도 평가를 위한 수치해석적 연구

안희철(Ahn, Heechul),유승경(You, Seung-Kyong),홍기권(Hong, Gigwon),김영호(Kim, Young-Ho),한중근(Han, Jung-Geun),윤중만(Yun, Jung-Mann) 한국지반신소재학회 2020 한국토목섬유학회 학술발표회 Vol.2020 No.11