Neighbour voxels of a list of voxels

17 vues (au cours des 30 derniers jours)
Razakamandimby Tiana
Razakamandimby Tiana le 18 Mai 2021
I am trying to find all the neighbours voxels of a list of voxels. I already used a function findNeigbours that I downloaded (https://www.mathworks.com/matlabcentral/fileexchange/68549-findneighbours) but it only works for a single voxel and I need to apply the function to a vector.
In my code, I used for loop but it's takiing too long time since the vector list is large. Any solution?
These are the lines I used in my code:
for i = 1:size(vector,1)
surrounding{i} = findNeighbours(vector(i), [[pxl_x, pxl_y, pxl_z], 26)
end
  2 commentaires
KSSV
KSSV le 18 Mai 2021
You can use inbuilt functions to achieve this fast. Show us how your voxels are.
Razakamandimby Tiana
Razakamandimby Tiana le 19 Mai 2021
The vector is in the excel file and the size of array in 3dimension is 60 x 60 x 67

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Matt J
Matt J le 18 Mai 2021
Modifié(e) : Matt J le 18 Mai 2021
If you have lists of xCoordinates, yCoordinates, and zCoordinates of the voxels, you may simply do,
[dx,dy,dz]=ndgrid([-1,0,1]);
dx=dx(:).'; dy=dy(:).'; dz=dz(:).';
X=xCoordinates(:)+dx; Y=yCoordinates(:)+dy; Z=zCoordinates(:)+dz; %neighbor coordinates
and if the voxel grid has dimensions MxNxP, you might then discard out-of-bounds voxel coordinates by doing,
X(X<1 | X>M)=nan;
Y(Y<1 | Y>N)=nan;
Z(Z<1 | Z>P)=nan;
  2 commentaires
Razakamandimby Tiana
Razakamandimby Tiana le 19 Mai 2021
Thanks but I have the voxels indexes not their coordinates. But I will try to get the coordinates from the inndexes and see if I get results faster
Matt J
Matt J le 19 Mai 2021
Just use ind2sub().

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Plus de réponses (1)

Razakamandimby Tiana
Razakamandimby Tiana le 20 Mai 2021
I could solve this issue. The following code gives all the neighbour voxels (connectivity 26 in 3D) of each voxels in the vector list.
vector % The attached excel file
matrix = [121 121 117];
conn = 26;
neighbor = arrayfun(@(vector) findNeighbours(vector,matrix,conn), vector,'UniformOutput', false)
  2 commentaires
Matt J
Matt J le 20 Mai 2021
But you are using arrayfun. I don't think you could be getting faster speed from arrayfun than with a loop.
Razakamandimby Tiana
Razakamandimby Tiana le 20 Mai 2021
you are right, finding the coordinates was faster. Thank you

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