Just tell us what you really want to do. If you just want to look at the image you'd use
That will show only non-zero pixels because the zero ones will show up as black.
If you want a list of them, you can use find() and that gives you a list of coordinates.
[rows, columns] = find(ima);
Now you have two vectors with the locations of the non-zero pixels. If you want them in an N-by-2 matrix of (x,y) coordinates, you can do
xy = [columns(:), rows(:)]
So that gives you basically everything you need. But we don't know what you really have in mind. You can't have an image show up where the zero pixels are like "holes" in the figure and you can see whatever is on your computer behind the figure as if the zero pixels were 100% transparent. And there is really no need for that anyway. So what do you really want to do? Do you just want to do some operation, like blurring or whatever, on the non-zero pixels? If you could do whatever you're thinking of, what would be the next step. You said you need an "output to be able to proceede with it.' Well, what does "proceede" mean to you? Do you want to measure intensity? Area of particles? What???
