viewgraphs.fm—12 
Nevatia - 16 
8/4/95 
Matching 
• Levels of Representation 
• Intensity 
• Edgels 
• Curves 
• Surfaces 
• Volumes 
• 2-Dor 3-D 
viewgraphs.fm—11 
8/4/95 
Matching (contd.) 
• Lower level descriptions easier to extract 
• matching algorithms are simpler e.g. cross-correlation 
• amount of data to be matched is large 
• descriptions are less distinct (more ambiguities) 
• Higher level descriptions are more distinct 
• matches should have fewer errors and ambiguities 
• more complex matching algorithm e.g. graph matching 
• size of descriptions is smaller 
• complexity and errors of descriptions