> If you put a sticker that looks like a toaster next to a banana, your classifier will see the toaster and not the banana. No it won't (as demonstrated in th

> If you put a sticker that looks like a toaster next to a banana, your classifier will see the toaster and not the banana. No it won't (as demonstrated in the video). This is the direct result of having CNNs. CNNs recognize pictures because of what a (at most) 32x32 set of pixels look like. It recognizes 1024 pixel patches as being toaster or not. So no, a toaster for an image classifier is VERY different from a toaster. It's how the corners of the surface work. It's the grid within the top. It's the reflecting aluminum near the plastic border. It's the ... A sticker doesn't have the vast majority of those properties. So a sticker with a toaster doesn't actually (usually) cause a misclassification (one imagines you can of course make the sticker good enough, but ...). But you can collect a lot of those 32x32 patches that are really, really "toastery" and then scale them, find something that is "somewhat fractal" (looks the same at different scales) and put that on a sticker. That looks nothing at all like a toaster to you, but it looks a hell of a lot like a toaster to a CNN. If you learn CNNs by knowing their predecessor "trick" (google "haar cascade") this makes a lot more sense. The reason we aren't fooled* is that our eyes don't recognize pixels. We recognize a wavelet encoding of a picture, not a grid of pixels. We recognize something that's like this description "a red blob, with a smaller green blob in the 2 o'clock position, a blue blob near the bottom, then that green blob is actually split into light green on the left and dark green on the right, and that blue blob really has a white top and a black bottom and ..." (you see you give details about a large average then afterwards describe the parts where that average is wrong. Rather than describing a grid top-left to bottom right you describe it as "average of the whole grid X, average of top left Y, average of top right B, average of bottom left Z, average of bottom right A, then recurse). * truth is you can fool humans partially with these stickers. You can make stickers that clearly are plastic stickers but you strongly feel that if you tough them you'll feel a cat's fur, or an insect/spider, or ... despite looking nothing like those things, and of course you can tell they're stickers). And of course, there's Dali.