Extract segments of 1's from binary matrix

Hi,

I'm looking for a way to extract segments of 1's in a arbirtay big binary matrix. For example, in this matrix:

0 0 0 0 0 0 0 0

1 1 1 1 1 0 0 1

0 0 0 1 0 0 0 1

0 0 0 1 0 0 0 1

I would like to extract 3 segments automatically, for example like:

(2, 1:5)

(2:4, 8)

(3:4, 4) or alternativy (2:4,4)

I'm not bound to the above notation regarding start and stop, it can be stored in any way, it is just an example.

I have played around with find() but I don't seem to be able to get it right

/Niklas

Answer 1

[Walter Roberson]

You can bwconncomp and pass in a connection array that is a central row or central column of 1s. You would do that twice, once for each direction, and ignore the components of size 1.

[Niklas Persson]

Thank you!

The function looks promising, however, I'm not sure what you mean by:

pass in a connection array that is a central row or central column of 1s. You would do that twice, once for each direction, and ignore the components of size 1.

I have given the function a go with a 4 connectivty input, but it sounds very intresting if it is possible to do it for one dimension at the time, but I don't see that in the documentation for the function?

/Niklas

[Niklas Persson]

Ah, I found it!

I should read the documentation more carefully

Thanks a lot!

[Walter Roberson]

To expand a little, bwconncomp accepts connectivity that is a number, but it also accepts connectivity as a mask array such as [0 0 0;1 1 1;0 0 0]