How to place a window at some particular positions in an image?

I have an impulse noise affected image of size 256x256.  At first stage, I detected the noisy and noise free pixels from the image. The detection performance is not satisfactory. I have created a noise map or a binary matrix having values 0 for noise and 1 for noise free pixels.  Now, from the noise map, for each noisy position, I need to impose a 3x3 window over the noisy image and find the uncorrupted pixels within the window. Can anyone help me to proceed this step?