how remove binary image noise in opencv?

Question

after convert image to binary image (black and white ) if there is any noise how can i remove that unwanted noise

you can see below image have some white noise inside the black area how can i remove noise using opencv

http://img857.imageshack.us/img857/999/blacknoise.jpg

Answer 1

You can achieve it with Erode and Dilate.

Your image after cvErode( in, eroded, NULL, 4):

And after cvDilate( eroded, dilated, NULL, 4):