matlabimage-processingimage-segmentationboundarysuperpixels

Image boundary based on superpixels

Superpixels that located in the image boundary can be specified manually using appropriate index (such as the following example for the second superpixel, L==2):

Segmented Image

Selected superpixel

In some cases it is needed to specify all of those superpixels located in the image boundary in an systematic and non-manual way, something similar to the image below:

superpixel image without edge superpixels

Is there any standard method to do that?

Solution

  • Given the labeled image L,

    lr = L([1,end],:);

    are all pixels along the left and right edges, and

    tb = L(:,[1,end]);

    are all pixels along the top and bottom edges. We can find all labels that touch the image edge by taking the unique values in those to sets:

    labels = unique([lr(:);tb(:));