I'm working on a project where I have to segment out nucleus of cells in a volume. I use random_walker with define markers for every nuclei. If I try to run it on the all volume the segmentation works well but it's very slow. So I used util.view_as_blocks function from scikit to split my image and markers and I loop over the different block using joblib:

rw_dapi_chunks = Parallel(n_jobs = 4)(delayed(segmentation.random_walker)(chunks[i,j],
                                     chunks_markers[i,j], beta = 3000, mode='cg_mg') for
                                      i in range(2) for j in range(2))

So I end up with a list of 4 images and if I combine these images (btw I'm not sure what is the best way for doing that? I just add them up in an empty array) everything work well, except that I end-up with nuclei with 2 different labels: