MATLAB: Bwlabel()- clarification and manipulation

4-connected objects and 8-connected objectsbwlabelfunction manipulation

I didnt understand the terms 4- connected objects and 8- connected bjects put in the econd argument of the function
Another question is- How does matlab determine the numbering of the objects? Can I use matlab to start numbering from the middle of the matrix? It doesn't matter to me if I need to use another function
Matar Maoz

Best Answer

See also http://en.wikipedia.org/wiki/Pixel_connectivity.
The ordering is arbitrary in bwlabel - and if you think about images with complex, arbitrary-shaped regions, it's clear that it would be very difficult to offer anything else in a general function.
You can use regionprops to find region centres, compute the distances od these from the image centre, then use sort to put the regions in order, and relabel.
Related Question