Recover myself from Dilate and Erode for noise reduction i have obtained some skin detection map (i post below two example of detection map). but, i'm using a normal webcam and the map is noisy. Not a lot, just a bit.
I think i can remove noise only with some combination of dilate and erode, and then threshold it.
But, like a stupid child, i have spent hours in trying to set parameters, use in different combination like: dilate twice, erode three times, blur, and an erode again and so on.
The only result i have obtained is to lost myself: it is not a robust approach at all.
So, for image like this, how can i use those super-popular filters? Or some advice for getting a nice contour of the face and removing the noise?

EDIT:
Those two are two different approach to skin recognition: backprojection and mahalonobis distance, using as training data the output of a simple haar face detection. I'm using both of them because with some illumination setting the first is better, for others the second is better. For my porpouse i can choose the best anytime I'm using my application.
First of all, are you using gray-scale morphology?  If so, then I would threshold the map first, to get a binary image, and then apply binary morphology to fill in gaps and get rid of the noise.

Second, instead of erosion and dilation, try opening and closing, which are higher order morphological operations. Opening is erosion followed by dilation with the same structuring element.  Closing is dilation followed by erosion.  

A good thing to try is to do an opening to get rid of the noisy specks, and then do a closing to fill in the gaps.  This will simplify your process to three operations: threshold, open, close.  So you would only need to tune three parameters: the threshold and the two structuring elements.