On Thu, 17 Jun 2010, João Pais wrote:
I would be very careful with your conception of skin if your going visual sensing, as it would be very difficult to make a skin detector that does not privilege certain skin tones.
Typically, face recognition involves using statistics about what a face looks like, so if the programme ships with a precomputed neural network and no tool to help add custom faces, chances are that it will miss a lot of people. I haven't tried such tools but I could guess that it would also miss people with unusually large beards and large mustaches,
http://esoterisme-exp.com/Section_main/Collection4/612-esoexp30.jpg http://blogue.branchez-vous.com/archives/doc-mailloux.jpg
A large mustache can cut a face in two, especially with certain angles and lightings. A large beard changes a face so much, that while googling for the latter guy, the first text I saw was someone wondering "what his face looks like" (without beard). A photoshop speculation :
http://blogue.branchez-vous.com/upload/2007/04/doc_mailloux.jpg
But algorithms can't come up with that kind of picture, and even from a human, there's always a possibility that the chin is wrong, if there's not enough of a hint of it on the picture.
Finally, black faces have much lower contrast, especially if the camera has a narrow range of intensity and is auto-adjusting to the average brightness of the scene. On top of that, any shininess of the skin can make reflections that can confuse the algorithm a lot.
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