fill holes on BW image with bwconncomp and labelmatrix

How can I fill holes on BW image with bwconncomp and labelmatrix without imfill. Give me simple example ,please. for example, I want to fill the star with white.

Answer 1

[Walter Roberson]

x = checkerboard(20,3,5);
y = x;y(rand(size(x))<.3) = 0;

labelmatrix = bwlabel(y);

to_fill = imclearborder(labelmatrix==0, 4);
[~, idx] = bwdist(labelmatrix ~= 0);
filled_label_matrix = labelmatrix;
filled_label_matrix(to_fill) = labelmatrix(idx(to_fill));

subplot(1,2,1); imagesc(labelmatrix);
subplot(1,2,2); imagesc(filled_label_matrix);

Note: for this purpose I defined "hole" in terms of 4 connectivity: with the default 8 connectivity, diagonal empty blocks were considered reachable from each other. You should try both ways and see which is better for your purpose.

[Alex Dashevsky]

Where is bwconncomp function ? for example, I want to fill the star with white.

[Walter Roberson]

You could call bwconncomp and throw the result away if you wanted.

... I am sensing that you are asking us to do a homework assignment for you :(

[Alex Dashevsky]

Please, help me. It is very intresting for me.

[Walter Roberson]

Call bwconncomp and throw the result away.

... Or explain why bwconncomp() must be used and imfill() must not be used.