viewgraphs.fm—2 
Nevatia - 11 
8/4/95 
Role of Matching and Grouping Operations 
in Automated Scene Analysis 
Ram Nevatia 
Institute for Robotics and Intelligent Systems 
Department of Computer Science 
Powell Hall 204 
University of Southern California 
Los Angeles, California 90089-0273 
Need for Grouping 
• 3-D Object Level Segmentation 
• Separate object from background 
• Segment among overlapping objects 
• Problems: 
• Low level boundaries are fragmented 
• Extraneous boundaries due to markings, shadows, noise... 
• Confusing detail: sidewalks, grass, architectural features... 
• Multiple images help but grouping problem remains