How to find out red pigment from capture image?

Please i m very thankful to all if u suggest me the answer as early as possible.

In my application I have to capture an image through mobile and then I have to find out red pigment color status and skin tone color.

How it could be possible through coding开发者_如何学Python in objective c.

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I just answered this question:

iPhone, modify UIImage to a target average color

You can pretty much use the same technique to look at the pixel values of an image and then run your algorithm on it.