If you're interested in this but have no background, the best place to start is "Fully Convolutional Networks for Semantic Segmentation" – https://people.eecs.berkeley.edu/~jonlong/long_shelhamer_fcn...

This is a very active field of research. Another thread worth pulling on is Mask R-CNN: https://arxiv.org/abs/1703.06870

It's not quite as simple as "this one has highest mAP, let's use it"; the tradeoffs are complex. In particular, as you can see in the image here, one thing DeepLab doesn't do is segment instances – so you get a mask of "people", not a mask per person. Mask R-CNN does a better job on that by design, because it predicts both bounding boxes and a mask per bounding box.