That is exactly what it is like. It does not matter what it looks like, how large or obvious, my brain will not recognize no matter how hard I look. For a while I tried using Post-It notes on the walls to remind me of things but I could not see them. I have to leave an object in my way to make sure I notice it.
My same brain though will notice the tiniest things, too many to list. Recognizing metals by their surface pattern and color, being able to instantly recognize stainless steel and other alloys.
Watching a TV show I quickly spotted a new manilla rope on what was supposed to be an antique because I saw the fine threads sticking out on its surface and they would have been worn away on a used rope. It goes on and on. I see patterns, mistakes in manufacture, the slightest color changes. I almost always notice the heads of screws anywhere I go and whether they are damaged which I intuit means they were quickly/badly installed without a proper clutch setting on the power driver.
I cannot however see mail, food, notes, my wall calendar etcetera. Sigh.
Yep. NAILED IT! I remember when I was younger asking my mom where the box of cereal was. It was on the table, in plain view, right in front of my face. I couldn't see it.