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3D reconstruction and modeling of urban buildings and architecture
Objective
To realize automatic/semi-automatic reconstruction and modeling of urban building or architecture with complex components
Challenges
- Photo-realistic & geometrically accurate
- Multi-images of target from different vantage points may not always be available
Approach
Employ constraints derived from shape symmetry
- Camera calibration by exploiting symmetry
- Duplication of virtual cameras
- Reconstruction by combining real and virtual pairs
- Modeling according to shape symmetry
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Vision-based human activity analysis
Objective
To recognize common (single or dual actor) actions in natural video sequences
Challenges
- To extract motion information in video
- To model temporal motions and their relationships
Approach
- Motion information encoded in motion trajectories
- Hierarchical levels of info extracted: appearance, intra-trajectories, and inter-trajectories
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Contextualized histograms for group activity analysis
Objective
To analyze group activities that involve multiple actors with interactions
Challenges
- To model interaction between different actors
- To keep the model complexity low
Approaches
- Raw motion information encoded in higher order local statistics
- Randomized forest employed to facilitate model simplification with supervision