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RE: recognising finger chording in video (started off

From: DLP <>
Date: Wed, 20 Jul 2005 14:51:56 -0500

This is my response to a conversation between paul_virak_khuong and I
off the list; my response included some questions to the list and I
thought it would be nice if we could get feedback on some of the
points from my response too. Cheers :-)

RE: finger chords, you might remember a string of posts some years ago
about finger chording recognition from video, and the resolution and
frame rate was an issue discussed at the time, but I can't find any of
those posts since the wearables.blu.org search feature seems to be
broken currently.
Is there a better way to search the list?

If you're familiar with the tech behind head-tracking mouses and eye
tracking I think you should do well in your research into this
chording recognition stuff. I think it's also been globbed into
discussions on this list and possibly elsewhere about gesturing, hand
gestures, and object tracking in video.

I do remember a keyboard device that watched the hands type on a
virtual keyboard space that was defined by a projection of a 2D
keyboard on a flat surface, the device used a laser and a camera to
figure out finger movements. The device was aimed at executives with
PDAs I think.
Ah yeah, heres the link firefox favors in an address bar search(Im
loving that, need to add wikipedia to that someday):
http://www.alpern.org/weblog/stories/2003/01/09/projectionKeyboards.html

I've been thinking about the way finger chords are seen in 2D space in
a 640x480 pixel image, and here is how I see the challenge. In two
parts, image processing, and then image analysis using computer vision
techniques to abstract finger positions from the processed image.

Firstly, the image processing might posterize the image sampled from
the webcam to a certain extent (to be determined later), then, impose
a new color map over the posterized image. Then I guess you make with
the edge detection right? Im not sure if this is true of many webcams,
but I have heard that a few have built-in image processing functions
like posterize for example; does anyone have any idea what I might be
talking about? Now that I think about it, uh, a color map rotation or
substitution(what is the right word here?) would be pointless if the
edge detection is done correctly, am I right?

Secondly, the image analysis for determining finger positions from the
processed image - I don't know page one about that so if anyone has
any resources on computer vision of notable interest I would greatly
appreciate any responses.

Thankyou Paul, now I have an even greater anticipation for my copy of
Intelligent Image Processing (Steve Mann, Hardcover) and my other new
finds on amazon :-)

Really can't wait to get my books :-)... never been more thrilled to
get books than anything else at any time in my life until about the
first of this year.

Thankyou all, and good day.

On 7/11/05, Paul-V Khuong <> wrote:
> --- DLP <> wrote:
> > I've never really been able to use newsgroups with
> > satisfaction(clients mostly) but now that I have
> > Thunderbird installed
> > and configured I will definitely see that I
> > subscribe now to
> > comp.lang.lisp. As for GCL, my attraction to it was
> > the "as fast as C"
> > claims and the FFI. SBCL and CMUCL are great and
> > like you said much
> > further ahead.
> While GCL compiles down to C, that doesn't make it "as
> fast as C". SBCL and CMUCL have much better optimisers
> (given declarations on arguments and a couple
> constructs Python can't infer through, speed is
> usually within 0.9x to 2x as slow).
>=20
> BTW, I might start working on recognising finger
> chords in video, since we finally have small webcams
> that do 640x480x32 fps. Do you have any references for that?
>=20
>=20
>=20
> ____________________________________________________
> Sell on Yahoo! Auctions =BF no fees. Bid on great items.
> http://auctions.yahoo.com/
>

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