| Summary: | 碩士 === 國立交通大學 === 資訊學院資訊科技產業專班 === 98 === In conventional surveillance systems, multiple screens are often required for displaying video from multiple cameras and may cause the difficulty of operators to keep track of targets due to the lack of special relationship among the screens. In this thesis, we develop an effective surveillance system with the 3-D environment model that integrates multiple scenes into one single comprehensive view. The system does not require accurate camera calibration and environment model construction with advanced equipments, and can provide a multiscale operating view for showing the status of the surveillance area.
To integrate the monitored area with camera views, the 3-D environment is first manually constructed by planar patch modeling. To map video contents to the corresponding areas of the 3-D model, different homography transformations are estimated for every pairs of image regions in the video contents and corresponding areas in the 3-D model. The planar patches in the 3-D model are automatically divided into different sizes and numbers of the smaller patches are determined by the intensity differences between the image polygons obtained from the homography transformation and texture mapping. Lookup tables are built beforehand for accelerating the coordinate mapping. In monitored scenes, 3-D objects including pedestrians, are projected to the imaging sensor planes through perspective transformation. Therefore, all 3-D objects will appear flattened on the planes in the 3-D model after texture mapping. To overcome this problem, we use billboarding method to model the 3-D moving objects. First, each foreground object extracted from the scene by background modeling is mapped to a billboard, and then vertically aligned to the ground plane. In this way we can adjust the direction of foreground objects according to the viewing direction. The proposed system can provide operators the situational awareness of the monitored site, including activities of the tracking targets through a comprehensive 3-D view.
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