[OnlineGladiator]

About a decade ago when I was still in school, I did some work in brain machine interfaces as well as a friend. I made an EEG from scratch, worked on the DSP and amplifications to make it all work, and also had access to a much more expensive state-of-the-art machine. While I didn't work directly on the project with my friend, at the time they came to the conclusion that non-invasive neural processing (so something topical like an EEG, no surgical implants) could process about 1 bit per second of useful information - the noise to signal ratio was about 1000:1. When most people read the raw data from an EEG they don't realize they can't even see the actual data - they're seeing eye movements, facial muscle twitches, and other noise artifacts that overwhelm the actual signal. I'm guessing the technology has improved a lot since then (I'm in another field now), but it's hard to imagine it gaining however many orders of magnitude in resolution necessary for this to be viable.

[henearkr]

Exactly. I have always been wondering how could the brain waves measurements not be overwhelmed by facial muscle signals.

[vanderZwan]

If you have multiple different points where you measure, which all have this overlapping signal problems but at different strengths, couldn't you hypothetically build up a model that "solves" these different weights and untangles the signals?

[dr_zoidberg]

Yes, but... At the end, you're still reconstructing pieces of information from something that was almost destroyed. Picture it this way: there are amazing deconvolution algorithms that can "undo" all sortf of noise and lack of focuse -- but the end result, however good to the original "bad" data isn't nearly as good as a well taken image to begin with.

Disclaimer: I work in image processing, so the example may be a bit obvious to me.

[vanderZwan]

Isn't what I described more like reconstructing a picture from many copies that were each destroyed in a unique fashion?

[dr_zoidberg]

Yes, that'd be a better analogy. My point was that, even if you had the best reconstruction in the world, having to reconstruct from a degraded source is worse than working from a good source to begin with.

[close04]

From a practical perspective they don’t have to be perfect or as food as the original, not even close, just good enough. “Good enough” though is also extremely hard to achieve, assuming it’s even possible with this technique.