By unsupervised I meant that the images have no label. I didn’t think that what I am doing counts as supervised (what is unsupervised learning then?). The data set is not limited, I am generating the images, so I can generate as many as I want (i.e. I can place the object wherever I want on the background). But I am looking for something more data efficient, hence why I was asking for some new insight, beside the plain old encoder-decoder architecture.