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xg15today at 9:24 AM1 replyview on HN

>The hole in the retina is sizeable (~9 full moons in the sky), but we don’t notice it because [...] (2) our brain automatically fills in gaps in our visual field by interpolation

I still remember this bit from school and various pop-sci book, but is it actually true? Is there really some group of neurons in the brain somewhere that actively tries to restore the "raw" visual information that was blocked by the blind spot?

Thinking of ANNs, I felt it was more realistic that higher layers in the visual cortex are mostly only using the visual information to find patterns anyway, and that they're robust enough they can still find those patterns without the data from the blind spot locations. (As long as a pattern isn't fully contained within the blind spot regions of course)

An analogy would be a QR code reader that can still parse the encoded information if a part of the QR code is missing - but it won't actually "reconstruct" the missing sections to do this.

But I don't know if it really works like this.


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glensteintoday at 10:12 AM

>(As long as a pattern isn't fully contained within the blind spot regions of course)

There are dedicated optical illusion/explainers that give you the experience of the brain patching over the space with neutral background, even if there's something there, like a symbol or a star.

So if it's something featureless or continuous, like a wall of your room that's a solid color, or a sheet of college ruled paper, the pattern can just be continued.

That said I would stress there's limits to how much of that you can do just by pattern extrapolation as opposed to deriving images from distinct and specific information in a given region of the visual field. You have to know enough about a stretch of visual space to know that it's appropriate to spread a pattern over it, and that's the thing the blind spot doesn't know.