How to split a Connected Component into components , after following particular criteria.????

Hi, After decomposing binary image into different connected components, I want extract each connected component and split a connected component if it has particular number of pixels in it. So that total number of connected components are increased....Is there any way to do that...

Answer 1

[Matt J]

Sure. Just loop over CC(i) and use the CC(i).PixelIdxList field to determine the number of components and to apply your splitting criterion. At the very end, modify all the CC(i).NumObjects values.

[Mohammad Bhat]

Sir, If I split a connected component , How will be the total number of connected components updated, will the split connected component share the same label with parent , After splitting each components (splitted if any) should have the different labels...Is it possible with above procedure...

[Matt J]

The output of bwconncomp (which is what you should be using) does not assign labels to components. It gives a structure array CC, where each CC(i) contains data on a component. You simply have to make CC longer and update its fields.

[Guillaume]

Well, the label is implicit, the label of CC.PixelIdxList{i} is i.

Note that CC is scalar. It is the PixelIdxList that is a vector (cell array). But Matt is essentially correct, just had the new half of the split component to the end of the PixelIdxList and adjust the NumObject field:

%e.g. split component 5 into 2 halves:
pixellist = CC.PixelIdxList{5};
pixelhalf1 = pixellist(1:floor(end/2));
pixelhalf2 = pixellist(floor(end/2)+1:end);
CC.PixelIdxList{5} = pixelhalf1;  %update component 5 with new list
CC.PixelIdxList{end+1} = pixelhalf2;  %add new component
CC.NumObjects = CC.NumObjects + 1;  %update object count

[Mohammad Bhat]

Thank You All

[Mohammad Bhat]

Sir, one problem occurred , You have taken example of dividing a connected component into two, How we can do for general (e.g. 3,4,5,....), becuase in pixelhalf1 = pixellist(1:floor(end/2)); pixelhalf2 = pixellist(floor(end/2)+1:end);

How we can tune above statements..

Answer 2

[Mohammad Bhat]

        pixellist = CC.PixelIdxList{k};
        pixelhalf1 = pixellist(1:floor(sizes(k)/2));
        pixelhalf2 = pixellist(floor(sizes(k)/2)+1:sizes(k));
        CC.PixelIdxList{k} = pixelhalf1;                 
        CC.PixelIdxList{k+1} = pixelhalf2;

But it is not reflected in original image......

Answer 3

[Mohammad Bhat]

Here , I have two connected component, I decomposed one of the connected component into two, but it is not reflected in the original image...