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Often when taking a photo of people, due to a failure during white balance or significant exposure problems, the tones of people faces are somewhat red or too dark or...
Basically what I am trying to do is to determine if skin colour on a detected face is good or not.
Lets make it simple and do this analysis for one race only - i.e. white people.
I will train algorithm (i.e. SVM) with colour features characteristic for bad and good faces. For face detection I will use Viola Jones algorithm, which will give me face bounding box.
What to do next? Maybe to search for a dominant colour inside a face bounding box and to represent it in a LUV color space?
I guess that way I will (ideally) get two clusters in a 2D space, one representing "good" coloured faces and other representing "bad" coloured faces.
Best regards, Matija.
I do not think that there is something like a "white race". Even "white" people have very different skin colors. See:
Look at: Google Images: "face". There will neither be a safe distinction between "good" and "bad" face colors, not between "white" and "non-white" races.
To get a good white balance, concentrate on a white object. Fortunately the white area of eyes is visible frequently and it is very reliable, because only a few diseases change this color noticably. From a scientific point of view, using white objects for a white balance is much more direct, than to classify the quality of a color based on different colors.
What I want to detect is this red/magenta effect sometimes added due to poor white balance...see example below...
To concentrate on eyes I need a good and reliable eye detector - which is not available at the moment. There are some detectors, but in general they are poor.
Maybe I can search for white regions inside face bounding box, but this doesnt seems to me like a handy solution.
Thats why I preffer using face detector. As I said earlier, I will train algorithm (i.e. SVM) with colour features characteristic for bad and good faces. New face will be analyzed and then added to one of these groups.
A paper on this was presented at the last Color Imaging Conference: http://www.imaging.org/IST/store/epub.cfm?abstrid=46635. Abstract, in part, says "....Through the experimental results, the proposed method achieves preferred skin color reproduction for each race....."