Xiu-Shen Wei, Yi-Zhe Song, Oisin Mac Aodha, Jianxin Wu, Yuxin Peng, Jinhui Tang, Jian Yang, Serge Belongie, Fine-Grained Image Analysis with Deep Learning: A Survey, TPAMI 2021 A good read on how sketch research has transformed the world of fine-grained analysis!