face connected skeleton 3d

How to convert 3d edge connected skeleton into face connected skeleton.

Regards,

Answer 1

[Naga]

Hello,

To convert a 3D edge-connected skeleton into a face-connected skeleton, you can use morphological operations to enforce 6-connectivity. Here's the implementation of the same:

% Sample 3D skeleton (binary volume)
skeleton = rand(10, 10, 10) > 0.8;  % Random binary 3D matrix

% Create a new binary volume for the face-connected skeleton
faceConnectedSkeleton = false(size(skeleton));

% Label connected components using 26-connectivity
cc = bwconncomp(skeleton, 26);

% Iterate over each connected component
for i = 1:cc.NumObjects
    % Extract the current component
    component = false(size(skeleton));
    component(cc.PixelIdxList{i}) = true;
    
    % Ensure face connectivity by dilating and eroding
    faceConnected = imerode(imdilate(component, strel('cube', 3)), strel('cube', 3));
    
    % Add the face-connected component to the new skeleton
    faceConnectedSkeleton = faceConnectedSkeleton | faceConnected;
end

% Visualize the results
figure;
subplot(1, 2, 1);
isosurface(skeleton);
title('Original Edge-Connected Skeleton');
axis equal; view(3);

subplot(1, 2, 2);
isosurface(faceConnectedSkeleton);
title('Face-Connected Skeleton');
axis equal; view(3);

1. The 'skeleton' variable is a binary 3D matrix representing the initial edge-connected skeleton.
2. 'bwconncomp' is used to label connected components in the skeleton using 26-connectivity.
3. 'imdilate' and 'imerode' are used with a 3x3x3 structuring element to enforce face connectivity. This ensures that each voxel is connected to its 6 face neighbors.
4. 'isosurface' is used to visualize the original and face-connected skeletons.

Refer to the following documentation links to read more about the respective functions:

• bwconncomp: https://www.mathworks.com/help/images/ref/bwconncomp.html
• strel: https://www.mathworks.com/help/images/ref/strel.html

This implementation provides a basic approach to converting an edge-connected skeleton to a face-connected one.