Re: [buildcheapeeg] BWView working

From: Jim Peters (jim_at_uazu.net)
Date: 2002-03-02 20:30:42


Dave wrote:
> Instead of packing the data files, screen shots, etc., in a zip file, I put
> together a quick web page and put it out at:
>
> http://www.psychosensory.com/bwview-images.html.

Right, I've just had a chance to look. The '-' bug isn't the only one
you're seeing -- do you see those thin lines across a couple of the
displays. There is something weird going on at a few very specific
frequencies that I haven't tracked down yet. It stays as a single
line even when you enlarge. It also isn't there all the time. I
wonder if somehow I'm corrupting the FFTW tables. I have an idea
about what might be doing this.

> Anyway, I have put instructions on how to use the data files with
> BWView on the page.

Thanks. It's very useful to have some more data files to test with,
especially as your files show up some new strange things going on.
For instance, your files show a huge amount of high-frequency junk
between 256/3 and 256/2 -- however it seems to come and go as the
position is moved -- so it might be a signal going in and out of phase
with my convolution function. Eeek! Making a nice wide window helps
somewhat. But I'm still not clear whether it is your data or my
analysis. I'll look at this some more.

> I'll tell you Jim--I am really struck with just how *beautiful* the
> images are. I think you have created a new art form. Now, if I
> could just fully understand how to interpret that art... :)

I think it's really tempting to get lost in the shapes -- it ends up
being like fractals. I was doing that, too. It helps to have a
purpose for looking at the file, I think! Anyway, I have some gaudily
coloured displays for the next version.

Regarding your subject, I have no idea. There is delta all over the
place, at about the same level as the alpha waves. But I'm just
starting to learn about interpreting this stuff. I'm also beginning
to understand Jim's need to see both channels at the same time.

Jim

-- 
Jim Peters (_)/=\~/_(_) jim_at_uazu.net
(_) /=\ ~/_ (_)
Uazú (_) /=\ ~/_ (_) http://
B'ham, UK (_) ____ /=\ ____ ~/_ ____ (_) uazu.net


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