Every way to segment an image
From a fixed, trained label set to a live point or text prompt -- which segmentation approach actually fits the task in front of you.
Start with what the task actually needs distinguished. Does every object of the same class need its own separate mask, or is one merged region per class enough? Is the label set fixed in advance and worth training for, or does the task need to segment a concept only named at inference time, with no retraining?
Fixed, trained label set
Every pixel gets a class label; same-class objects merge into one region.
Adds a separate mask per object instance on top of the class label.
Term
Mask R-CNN
The standard two-stage architecture that actually produces instance segmentation's per-object masks.
Open-ended, prompted at inference time
A point, box, or text prompt segments whatever it indicates, with no fixed label set to retrain against.
Extends a single prompted object to "every instance of this concept" from a description alone.