Image Processing on mouth ROI

[tommy_chai]

The attachment "m-004-1.zip" contains "ipskin.pgm" and "m-004-1.pgm".
"m-004-1.pgm" is the mouth region after opening(3x3) and closing(2x2) and labeling.
"ipskin.pgm" is the raw image. Both of the image in binary format.
guys, is it possible to do some image processing techniques and obtain only the mouth region at the middle?
I have tried to get the largest connected component but i got the moustache instead of mouth. What terms can i set so that every image will get the lips only and the rest (moustache and small connected component) become black background?

Thank you.

Best regards,
Tommy