what is bwlabel function doing ?

i want to understand the logic of bwlabel function ....

L = bwlabel(BW,4) what is it doing ? and L = bwlabel(BW,8) ... i want someone to express for me ... i read about it but i didnt understand

Answer 1

[Image Analyst]

It's giving a unique ID number to every connected blob. If you have two squares just touching at the corner, do you consider that to be just one blob, or two? If it's one blob, then use 8 connectivity. If it's two blobs then use 4 connectivity which says that the blobs need to touch on one of the 4 vertical or horizontal edges, not on one of the corners.