• Title/Summary/Keyword: 그림자 폐색 처리

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Improvement of interpretability for color aerial imagery by combining shadow effects correction and Lidar data (Lidar 자료와 그림자 보정을 통한 컬러항공사진 판독력 향상)

  • Sohn, Hong-Gyoo;Yun, Kong-Hyun
    • 한국지형공간정보학회:학술대회논문집
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    • 2003.09a
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    • pp.177-181
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    • 2003
  • 최근 고해상도의 영상과 컬러항공영상의 출현과 더불어 도심지역의 지물 지모에 대한 상세한 묘사가 가능해지고 있다. 하지만 도심지역의 지물 지모의 복잡성으로 인하여 지물의 추출이 쉽지 않다. 특히, 건물에 의한 가림, 그림자에 의한 정보 왜곡 등의 발생으로 지형정보 추출의 어려움을 겪고 있다. 건물에 의한 폐색은 다른 위치에서 촬영을 하므로서 보정을 할 수 있지만 그림자에 의한 영향은 촬영위치에 상관없이 항상 발생한다. 본 연구에서는 도심지역에서 촬영한 컬러항공사진에서 그림자에 의한 정보 왜곡을 LIDAR 자료와 수치지도를 이용하여 보다 자동화된 과정으로 처리하므로서 그 판독력을 증대시키고자 한다.

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Shadow Removal in Front Projection System using a Depth Camera (깊이 카메라를 이용한 전방 프로젝션 환경에서 그림자 제거)

  • Kim, Jaedong;Seo, Hyunggoog;Cha, Seunghoon;Noh, Junyong
    • Journal of the Korea Computer Graphics Society
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    • v.21 no.3
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    • pp.1-10
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    • 2015
  • One way to create a visually immersive environment is to utilize a front projection system. Especially, when enough space is not available behind the screen, it becomes difficult to install a back projection system, making the front projection an appropriate choice. A drawback associated with the front projection is, however, the interference of shadow. The shadow can be cast on the screen when the user is located between the screen and the projector. This shadow can negatively affect the user experience and reduce the sense of immersion by removing important information. There have been various attempts to eliminating shadows cast on the screen by using multiple projectors that compensate for each other with missing information. There is trade-off between calculataion time and desired accuracy in this mutual compensation. Accurate estimation of the shadow usually requires heavy computation while simple approaches suffer from inclusion of non-shadow regions in the result. We propose a novel approach to removing shadows created in the front projection system using the skeleton data obtained from a depth camera. The skeleton data helps accurately extract the shape of the shadow that the user cast without requiring much computation. Our method also utilizes a distance field to remove the afterimage of shadow that may occur when the user moves. We verify the effectiveness of our system by performing various experiments in an interactive environment created by a front projection system.

Development of Video-Detection Integration Algorithm on Vehicle Tracking (트래킹 기반 영상검지 통합 알고리즘 개발)

  • Oh, Jutaek;Min, Junyoung;Hu, Byungdo;Hwang, Bohee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5D
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    • pp.635-644
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    • 2009
  • Image processing technique in the outdoor environment is very sensitive, and it tends to lose a lot of accuracy when it rapidly changes by outdoor environment. Therefore, in order to calculate accurate traffic information using the traffic monitoring system, we must resolve removing shadow in transition time, Distortion by the vehicle headlights at night, noise of rain, snow, and fog, and occlusion. In the research, we developed a system to calibrate the amount of traffic, speed, and time occupancy by using image processing technique in a variety of outdoor environments change. This system were tested under outdoor environments at the Gonjiam test site, which is managed by Korea Institute of Construction Technology (www.kict.re.kr) for testing performance. We evaluated the performance of traffic information, volume counts, speed, and occupancy time, with 4 lanes (2 lanes are upstream and the rests are downstream) from the 16th to 18th December, 2008. The evaluation method performed as based on the standard data is a radar detection compared to calculated data using image processing technique. The System evaluation results showed that the amount of traffic, speed, and time occupancy in period (day, night, sunrise, sunset) are approximately 92-97% accuracy when these data compared to the standard data.

Generation of DEM by Correcting Blockage Areas on ASTER Stereo Images (ASTER 스테레오 영상의 폐색영역 보정에 의한 DEM 생성)

  • Lee, Jin-Duk;Park, Jin-Sung
    • Journal of the Korean Association of Geographic Information Studies
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    • v.13 no.1
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    • pp.155-163
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    • 2010
  • The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on-board the NASA's Terra spacecraft provides along-track digital stereo image data at 15m resolution with a base-height ratio 0.6. Automated stereocorrelation procedure was implemented using the ENVI 4.1 software to derive DEMs with $15m{\times}15m$ in 43km long and 50km wide area using the ASTER stereo images. The accuracy of DEMs was analyzed in comparison with those which were obtained from digital topographic maps of 1:25,000 scale. Results indicate that RMSE in elevation between ${\pm}7$ and ${\pm}20m$ could be achieved. Excluding cloud, water and building areas as the factors which make RMSE value exceeding 10m, the accuracy of DEMs showed RMSE of ${\pm}5.789m$. Therefore for the purpose of elevating accuracy of topographic information, we intended to detect the cloud areas and shadow areas by a landcover classification method, remove those areas on the ASTER DEM and then replace with those areas detached from the cartographic DEM by band math.