Lei Ke, Yu-Wing Tai, Chi-Keung Tang, "Deep Occlusion-Aware Instance Segmentation With Overlapping BiLayers" CVPR2021 https://openaccess.thecvf.com/content/CVPR2021/html/Ke_Deep_Occlusion-Aware_Instance_Segmentation_With_Overlapping_BiLayers_CVPR_2021_paper.html