[SDL] Problem with SDL_image on Windows

Kikolani info at tajjada.com
Mon Jul 26 12:48:54 PDT 2010


This sounds very cool, I'd love to hear what comes of this! :)

On Sun, Jul 4, 2010 at 5:02 AM, Alex Barry <alex.barry at gmail.com> wrote:
> After doing a lot of searching, it looks like by best bet is something
> called "EyeWriter" - it'll take a few tweaks, but once it's done, i'll post
> the code to link it up with SDL's events (probably as a user-event), as well
> as a demo application.
>
> Thanks,
> -Alex
>
> On Sat, Jul 3, 2010 at 11:05 PM, Kenneth Bull <llubnek at gmail.com> wrote:
>>
>> On 03/07/2010, Alex Barry <alex.barry at gmail.com> wrote:
>> > Maybe the community can come up with some creative suggestions?
>> > This is probably how I'll have to approach it:
>>
>> > Have two infrared lights, one approximately inbetween his eyes, the
>> > other
>> > covered from the camera, but pointed at his eye.  I put the camera on
>> > infrared mod, and I should get the light near the middle of his face,
>> > and
>> > the light reflecting off his eye - from there, I'd assume the pupil
>> > would
>> > reflect the most, so I just compare the distance/angle between the two
>> > lights to approximate an x/y coordinate pair.
>>
>> I don't think the pupil is more reflective really, but the pupil is
>> where you would find an _additional_ reflection.  Light reflects off
>> both the outer and inner surface of the lens.  If you compare the
>> positions of the reflections, you can find the direction the eye is
>> focused on relative to the light source and camera.  You need a really
>> good camera and a dark room though.
>>
>> Alternatively, you can track the position of the iris or pupil by
>> color, since there's a big contrast between them and the rest of the
>> eye.  You can use the "red eye" effect to increase this contrast.
>>
>> try these links:
>> http://en.wikipedia.org/wiki/Eye_tracking#Tracker_types
>> http://www.diku.dk/hjemmesider/ansatte/panic/eyegaze/node9.html
>>
>> If you can't track the eye accurately enough to pinpoint a location on
>> screen, you could roughly track large eye movements instead and use
>> them to bump a cursor around.  So if he looks left, it bumps the
>> cursor to the left, if he looks right, it bumps the cursor to the
>> right, etc.
>>
>> > Does this sound reasonable?  This would also make it easy for blink
>> > detection, and I could use three lights, one for each eye, and the last
>> > one
>> > for a reference point.
>> >
>>
>> You should only need one light.  Unless you're using a laser (which
>> you shouldn't), each light will reflect off his entire face, not just
>> wherever you point it.  You could recognize the position of his head
>> by contrast with the background (white wall, pillow, etc) (this is
>> where OpenCV might help), then recognize the position of his eyes by
>> the higher reflectivity.  That's before you actually get around to
>> figuring out where he's looking though.
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