How to compute regions of matrix

Hi all

Let's say we have the following matrix:

    0 0 0 0 0 0
    0 1 0 0 0 0
    1 1 0 0 0 0
    1 1 0 0 0 0
    0 0 0 0 0 0
    0 0 0 1 1 1
    0 0 0 0 1 1
    0 0 0 0 0 0

I want to calculate the size of every connected region of 1s and also get the corresponding matrix elements of each region. The size should be computed as (width + heigth) / 2.

In the example the bottom left region would have size (2 + 3) / 2 and the bottom right region would have size (3 + 2) / 2.

Additional to the size of the regions I also want the corresponding entries of the regions, i.e. region 1 has entries (2,2), (3,1), (3,2) and so on.

How can this be done in Matlab?

I'm looking forward for the answers and wish everybody all the best.

Answer 1

[Jos (10584)]

Trivial, provided you have the image processing toolbox. Take a look at BWLABEL and REGIONPROPS

M = [ 0 0 0 0 0 0
    0 1 0 0 0 0
    1 1 0 0 0 0
    1 1 0 0 0 0
    0 0 0 0 0 0
    0 0 0 1 1 1
    0 0 0 0 1 1
    0 0 0 0 0 0]
P = regionprops(bwlabel(M),'boundingbox')

The last two values of the field BoudingBox will give you the height and the width of each connected region.