My brain just makes the assumption based on previous knowledge and colors.
In a sense, poor vision just makes you aware of what deludes everybody else. Because people with 20/20 vision don’t see what’s really there, either, unless something shocks them into overriding brain habits and really looking. True story: A couple of decades ago (when I was younger and still had 20/20 vision), I was hiking in a State Park in January, after a fresh snow. Everything was white and pristine and beautiful. I spotted a big, brown log half buried in the snow and decided to rest for a bit. I threw off my backpack and plunked down on the log… Which proceeded to stand up, tower over me, and lumber away into the woods. It was a gigantic Elk, sleeping in the snow. And I probably would have recognized that before sitting down if I’d been paying attention. But my eyes saw a large brown object in the snow, my brain labelled it “log,” and the rest is history.
