Apply a function to a traced portion of an image only.

Hi There,

So I have a 3d bmp file which consists of an image of a face: A.bmp.

The image has a circular face with a white background. I have a piece of code that takes chunks of the image and shuffles them around - however I have been trying to apply this selectively to the face and not the background.

I thought a tracing function could work well, and there is one for 3d matrix files, being bwconncomp - this gives you a connectivity value, image size, number of objects and a pixel list, though I'm not really sure about the usefulness of these values for what I am trying to do. I was hoping to get co-ordinates for the face so I could use those to apply the shuffle function.

I tried converting the image to 2d matrix with rbg2gray, but this looses a lot of boundaries and you end up with a very strange shuffled image.

So my question is: is there a way to use bwconncomp to get the co-ordinates of the face, or alternatively convert the image so that it is compatible with the 2d tracing functions?

Thank you.