We report quantitative metrics like CIDEr (Vedantam et al., 2015), BLEU (Papineni et al., 2002), METEOR (Denkowski and Lavie, 2014), and ROUGE-L, as is often reported by works in image captioning.
we consider the following four features: the length, width, and area of the smallest rectangular region enclosing cluster z i , and the number of active elements in mask C z i .