Yehao Li Ting Yao 0003 Yingwei Pan Hongyang Chao Tao Mei 0001 12497-12506 2019 CVPR http://openaccess.thecvf.com/content_CVPR_2019/html/Li_Pointing_Novel_Objects_in_Image_Captioning_CVPR_2019_paper.html https://doi.org/10.1109/CVPR.2019.01278 conf/cvpr/2019 db/conf/cvpr/cvpr2019.html#LiYPCM19