Cascading classifiers for detection
	For efficiency, apply less accurate but faster classifiers first to immediately discard windows that clearly appear to be negative; e.g., Ø Filter for promising regions with an initial inexpensive classifier Ø Build a chain of classifiers, choosing cheap ones with low false negative rates early in the chain
		Fleuret & Geman, IJCV 2001 Rowley et al., PAMI 1998 Viola & Jones, CVPR 2001
							Figure from Viola & Jones CVPR 2001
				K. Grauman, B. Leibe