[sldev] Anyone here with OpenCV experience?

[Jan Ciger]

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Dahlia Trimble wrote:
> Overkill? I'm not so sure. Consider the extreme variations in contrast
> that something like this would be exposed to out in the field. Lighting
> is uncontrolled and unpredictable. A major source of light on a user's
> face may well come from the image shown on the monitor, and may reflect
> off of the user's glasses. Facial features are variable and skin tone,
> eyebrow color, and other facial hair could further confuse any detection
> methods. Background lighting and objects other than the user could cause
> false detections. Also the camera could not be controlled, Could one
> reasonably expect users to purchase a standard webcam from a single
> vendor when many computers come with integrated webcams?

No, but that isn't the point. It doesn't need to be 100% perfect and
robust - even the Logitech's solution is not. And yes, actually most of
the lighting in an average room is stable - and can be compensated for.
For example, the paper I have sent the link to deals with the lighting
issues by calibration - it takes a picture of a skin patch (your face)
and uses that to create a model of your skin color. That compensates for
all the skin and lighting issues, even lot of camera parameters.

An actual application would probably build a background model too to
make the detection more robust. Again, a rather simple task.

> 
> Somehow I don't think simple methods demonstrated that in a lab
> environment will perform well at all given all these potential confounds
> in all user environments. Whatever is implemented would need to be
> subjected to extensive user testing if any kind of wide acceptance would
> be desired.

Sony is doing a brisk business with their hugely popular EyeToy series
that is using these simple algorithms that you believe do not work. Do I
need to say more?

Regards,

Jan

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