(a) MAPs on single-concept  and
(b) P@10s on single-concept and
(c) MAPs on 2-concept and
(d) P@10s on 2-concept and
(e) MAPs on 3-concept and
(f) P@10s on 3-concept and
Figure 4: MAPs and P@10s (%) of semantic image retrieval for rare concepts and frequent concepts on MIR Flickr 2011.