Semantic and Instance Segmentation2026-11-11computer‑visionsemantic‑segmentationinstance‑segmentationfully‑convolutional‑networkstransposed‑convolutionupsamplingu‑netmask‑r‑cnnroi‑aligndeep‑learningcomp9517agenticLabelling every pixel: fully convolutional networks, upsampling layers and their output-size trap, U-Net's skip connections, and Mask R-CNN with RoI Align.