Computer Vision: U-Net
Convolutional Networks for Biomedical Image Segmentation
U-Net is one of the most famous image segmentation architectures. It was proposed in 2015 by Olaf Ronneberger, Philipp Fischer, Thomas Brox (University of Freiburg, Germany). 
One should read the full paper to really relish the architechture. Following is an outlines treatment, suitable for beginners.
An end-to-end segmentation technique- U-Net takes a raw image in and outputs a segmentation map of the image.