Find connected components in binary image
The functions bwlabel
, bwlabeln
,
and bwconncomp
all compute connected components
for binary images. bwconncomp
replaces the use
of bwlabel
and bwlabeln
. It
uses significantly less memory and is sometimes faster than the other
functions.
To extract features from a binary image using regionprops
with
default connectivity, just pass BW
directly into regionprops
(i.e., regionprops(BW)
).
To compute a label matrix having more memory-efficient
data type (e.g., uint8
versus double
),
use the labelmatrix
function on the output of bwconncomp
.
See the documentation for each function for more information.
The basic steps in finding the connected components are:
Search for the next unlabeled pixel, p
.
Use a flood-fill algorithm to label all the pixels
in the connected component containing p
.
Repeat steps 1 and 2 until all the pixels are labeled.