MATLAB: How to find 26 neighbors of point with coordinates of (i,j,k)

digital image processingimage analysisimage segmentationmatrix arraymatrix manipulation

I have a stack of images in a 3D matrix.

How can I find 26 neighbors of a specific voxel with coordinates of (i,j,k) in Matlab?

Your help is appreciated.

To get a 27 element cube around the voxel, do this:

neighbors = matrix3d(i-1:i+1, j-1:j+1, k-1:k+1);

Then turn it into a column vector like this:

neighbors = neighbors(:);

Then delete the i,j,k element to get the final 26 neighbors, by deleting the middle element of the column vector:

neighbors[14] = [];  % Now we're done!  We have a list of 26 voxel values.

matrix3D is the variable 3D matrix you have. You have not defined it.

matrix3d = rand(10,10,10) ;
% say i = 1, j = 1
i = 2 ; j=3, k = 2
neighbors = matrix3d(i-1:i+1, j-1:j+1, k-1:k+1)

You may use knnsearch to get the nearest neighbors. Read about knnsearch