What is Mask R-CNN and how does it extend Faster R-CNN?

Mask R-CNN adds a segmentation branch to Faster R-CNN for pixel-level object masks.

Mask R-CNN extends Faster R-CNN by adding a parallel branch that predicts binary masks for each Region of Interest (RoI). It replaces ROI pooling with ROI Align to avoid quantization errors, improving spatial alignment. The architecture simultaneously predicts class labels, bounding boxes, and segmentation masks.