Live data from Hacker News

High-res image reconstruction with latent diffusion models from human brain

github.com

121–130 of 170 posts

Re: High-res image reconstruction with latent diffusion models from human brain

#121
post #29

As people and groups increasingly move this direction do we think about vectors for abuse in 10, 20 or 50+ years? The human mind is considered the only place where we have true privacy. All these efforts are taking that away. At this rate all notions of privacy will soon be dead.

> do we think about vectors for abuse in 10, 20 or 50+ years?

Of course, but what's to be done about it? Should we outlaw research like this?

Re: High-res image reconstruction with latent diffusion models from human brain

#122
post #29

As people and groups increasingly move this direction do we think about vectors for abuse in 10, 20 or 50+ years? The human mind is considered the only place where we have true privacy. All these efforts are taking that away. At this rate all notions of privacy will soon be dead.

If brainwave scanning reaches a point where those instruments are pervasive, I am sure tinfoil hats or some technology similar in spirit will advance accordingly.

Re: High-res image reconstruction with latent diffusion models from human brain

#123
post #28

I immediately found the results suspect, and think I have found what is actually going on. The dataset it was trained on was 2770 images, minus 982 of those used for validation. I posit that the system did not actually read any pictures from the brains, but simply overfitted all the training images into the network itself. For example, if one looks at a picture of a teddy bear, you'd get an overfitted picture of anot…

I'm definitely not an expert in this subject, but even if the model is overfitted, doesn't the fact that it can pull out the similar images at all give credit to the idea that a larger, non-overfitted model could actually work as the paper describes? It means that there does exist some correlation between the shown subject, the captured fMRI data, and the resulting location in latent space.

If things are being overfit you should typically make the model smaller - not larger.

Re: High-res image reconstruction with latent diffusion models from human brain

#124
post #28

Earlier quoted context omitted.

I'm definitely not an expert in this subject, but even if the model is overfitted, doesn't the fact that it can pull out the similar images at all give credit to the idea that a larger, non-overfitted model could actually work as the paper describes? It means that there does exist some correlation between the shown subject, the captured fMRI data, and the resulting location in latent space.

Nope. If you train a model where the input is an integer between 1 and 10, and the output is a specific image from a set of ten, the model will be able to get zero loss on the task. That is what's happening here.

It's still a legitimate direction to pursue. Once you get to large enough training sets, it's basically the same way our own brains work. We don't perceive or remember all the details of a building - just "building, style 19B", plus a few extra generic parameters like distance, angle, color and so on. Totally manageable for deep learning to recognize, and perhaps even combine.

Re: High-res image reconstruction with latent diffusion models from human brain

#125
post #43

Earlier quoted context omitted.

There was a video many years ago (early 2010s?) demoing a similar technology, which would overlay and blend many images on top of each other to make a fuzzy image approximating what was actually being viewed. Edit: found it! https://youtu.be/nsjDnYxJ0bo

The youtube video quotes a paper by the same author, so it's probably the same group's work. I wonder why didn't they used an approach similar to the one in the video using SD - it looks more viable.

Because it's from 11 years ago when SD wasn't around.

Re: High-res image reconstruction with latent diffusion models from human brain

#126
post #76

Earlier quoted context omitted.

Joke's on them, my passwords are entirely unpronounceable

only my fingers know my passwords. And no way all ten will rat me out

oh yeah, maybe they'll put electrodes on your fingers! JK - this doesn't seem like a viable approach.

Re: High-res image reconstruction with latent diffusion models from human brain

#127
post #46

Earlier quoted context omitted.

In this specific case I agree, since the model may be overfitted, it seems like it's currently just a glorified object classifier based on what was in the training data, but the fact that it works at all may indicate that the underlying idea has merit. They would probably have to train a much larger network to see if it's able to separate features distinctly enough using the input fMRI data to be useful.

The problem is that it's impossible to know what is in the fMRI data and what is hallucinated by the reconstruction. In this case, the real bear has a blue ribbon and the "reconstructed" bear ha a red ribbon. Is the ribbon in the fMRI data and the computer choose the wrong color, or most of the images in the training set had ribbons and the computer just added one. Imagine this something like this is used in the futu…

> Imagine this something like this is used in the future to get something like https://en.wikipedia.org/wiki/Facial_composite . People may give too much importance to the details and arrest someone only because the computer imagined some detail, like the logo in the baseball cap.

Wow, tech not working to tech might kill someone went super fast here.

Re: High-res image reconstruction with latent diffusion models from human brain

#128

I immediately found the results suspect, and think I have found what is actually going on. The dataset it was trained on was 2770 images, minus 982 of those used for validation. I posit that the system did not actually read any pictures from the brains, but simply overfitted all the training images into the network itself. For example, if one looks at a picture of a teddy bear, you'd get an overfitted picture of anot…

Its still picking out the correct "overfitted" images, which is remarkable. Theoretically, the results would scale to more training images... we just need to fMRI all of LAION-5B. Easy peasy.

The only question is whether more images will confuse the model or not?

Re: High-res image reconstruction with latent diffusion models from human brain

#129

Earlier quoted context omitted.

I'm "thinking in words" this entire thread as I read it. Do some people read without hearing the words in their head?

Yeah, personally - and this might be a controversial opinion - I think most people who say they have an inner monologue are actually misattributing their experience of subvocalization while either reading text, or planning hypothetical conversations with other people (like a child might speak to their imaginary friend). It seems dubious to label that a monologue, because it depends on external stimuli (either the tex…

Wow, this is interesting, I thought pretty much everyone had an internal monologue. It feels like a colorblind person sharing the suspicion that everyone is just making up this other color spectrum.

Re: High-res image reconstruction with latent diffusion models from human brain

#130

Earlier quoted context omitted.

Citation definitely needed. I have a nearly constant internal monologue that is 100% composed of words.

Do you know what it's going to say next? If not, who's generating each new word? And if yes, then isn't this just subvocalization?

> If not, who's generating each new word

Do you know what your next thought will be? If so, how? Did you think it before you thought it?

Post reply on HN