How do I fill 4-connected cells in an matrix?

I have a problem. I would like to convert a matrix like this:

A=[ 1 1 1 0 1 0; 1 0 1 1 0 1; 1 1 1 0 1 0; 0 0 0 0 0 0]

to

B=[1 1 1 0 1 0; 1 1 1 1 1 1 ; 1 1 1 0 1 0; 0 0 0 0 0 0]

that is fill 4-connected cells containing 0 with 1. I have tried to use imfill but I think it is not useful in this specific case.

Answer 1

[Steve Eddins]

>> imfill(A,4,'holes')
ans =
     1     1     1     0     1     0
     1     1     1     1     1     1
     1     1     1     0     1     0
     0     0     0     0     0     0

[Julia]

Hi,

thank you for the answers but this option does not give exactly what I need. The example matrix was probably not a good one. I show another example. If:

BW1 = logical([1 0 0 0 0 0 0 0

1 1 1 1 1 0 0 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0

1 1 1 1 0 1 1 1

1 0 0 1 1 0 1 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0]);

with the command:

BW2 = imfill(BW1,4,'holes');

you get:

BW2 =

1 0 0 0 0 0 0 0

1 1 1 1 1 0 0 0

1 1 1 1 1 0 1 0

1 1 1 1 1 1 1 0

1 1 1 1 1 1 1 1

1 0 0 1 1 1 1 0

1 0 0 0 1 1 1 0

1 0 0 0 1 1 1 0

but I would like to fill only the cells with 0 which are 4-connected with 1s, that is, I would like to get the following matrix instead:

BW3 =

1 0 0 0 0 0 0 0

1 1 1 1 1 0 0 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0

1 1 1 1 1 1 1 1

1 0 0 1 1 0 1 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0

Do you know if there is still an easy way to get this?

Again, thank you in advance.

Answer 2

[Anathea Pepperl]

If you have the Image Processing Toolbox, then imfill should work in this case. I tried replicating your code here:

   A = [ 1 1 1 0 1 0; 1 0 1 1 0 1; 1 1 1 0 1 0; 0 0 0 0 0 0]
   B = [1 1 1 0 1 0; 1 1 1 1 1 1 ; 1 1 1 0 1 0; 0 0 0 0 0 0]
   C = imfill(A, 'holes')
   isequal(C, B)

And using imfill to generate the matrix C gave me the same result as B.

[Julia]

Hi,

thank you for the answers but this option does not give exactly what I need. The example matrix was probably not a good one. I show another example. If:

BW1 = logical([1 0 0 0 0 0 0 0

1 1 1 1 1 0 0 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0

1 1 1 1 0 1 1 1

1 0 0 1 1 0 1 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0]);

with the command:

BW2 = imfill(BW1,4,'holes');

you get:

BW2 =

1 0 0 0 0 0 0 0

1 1 1 1 1 0 0 0

1 1 1 1 1 0 1 0

1 1 1 1 1 1 1 0

1 1 1 1 1 1 1 1

1 0 0 1 1 1 1 0

1 0 0 0 1 1 1 0

1 0 0 0 1 1 1 0

but I would like to fill only the cells with 0 which are 4-connected with 1s, that is, I would like to get the following matrix instead:

BW3 =

1 0 0 0 0 0 0 0

1 1 1 1 1 0 0 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0

1 1 1 1 1 1 1 1

1 0 0 1 1 0 1 0

1 0 0 0 1 0 1 0

1 0 0 0 1 1 1 0

Do you know if there is still an easy way to get this?

Again, thank you in advance.

Answer 3

[Steve Eddins]

I posted an answer (using bwhitmiss) in response to your new question.