[D][R] What is the current state of the art for unsupervised image segmentation?

I am working on 4k image data for a PhD project and we have a ton of unlabeled images that needs to be segmented. The advisor wants to start with unsupervised image segmentation. Which algorithm should I start with playing and tweaking?

algorithm art current data image image data images machinelearning phd playing project segmentation state state of the art unsupervised