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How to use voxels of different sizes to measure the volume of a 3D object using Matlab?

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M.S. Khan
M.S. Khan on 3 Sep 2020
Commented: M.S. Khan on 7 Sep 2020
Hi Dear Community members,
i want to measure the volume of a cone using voxels. i am new in this field of voxels. Using the first link, a sphre of radius 8 has been voxelized. After voxelization, how can we count the total number of voxels. how to fix the size of voxels?
Using this method of author, how can we voxelize the cone to measure its volume. The attached file has xyz - coordiantes for the cone.
Thanks in advance for all cooperation and guidance.
% This scrypt illustrates the use of VoxelPlotter function to visualize
% voxel data stored in a 3d matrix
clear all
close all
clc
%Generating sinthetic input
gridesize=16;
R=8;
VoxelMat=zeros(gridesize,gridesize,gridesize);
for i=1:gridesize
for j=1:gridesize
for k=1:gridesize
if (i-gridesize/2)^2+(j-gridesize/2)^2+(k-gridesize/2)^2<R^2
VoxelMat(i,j,k)=1;
end
end
end
end
[vol_handle]=VoxelPlotter(VoxelMat,1);
view(3);
daspect([1,1,1]);
set(gca,'xlim',[0 gridesize], 'ylim',[0 gridesize], 'zlim',[0 gridesize]);

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Accepted Answer

Bruno Luong
Bruno Luong on 3 Sep 2020
Edited: Bruno Luong on 4 Sep 2020
Vol estimate = 1.2692e+06
xyz = load('Cone_20000_points.txt');
[minxyz,maxxyz] = bounds(xyz,1);
N = 30*ones(1,3); % resolution, select with care
ijk = min(max(ceil((xyz-minxyz)./(maxxyz-minxyz).*N),1),N);
C = accumarray(ijk,1);
b = C > 0;
p = mean(C(b))
if p < 2 % Sanity check
warning('Your bin is too small, inaccurate result');
end
Vol = sum(b,'all') * prod((maxxyz-minxyz)./N)

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Bruno Luong
Bruno Luong on 4 Sep 2020
Where you get this
number_of_voxels = numel(b) % To count number of voxels using above code.
from???? If you change the calculation of my code then it's normal you get wrong result.
M.S. Khan
M.S. Khan on 5 Sep 2020
Greetings Bruno, sorry for late reply. i was out of station.
Yes true, i got wrong results. Could you pleasue give me some tips how to count the number of voxels and how to measure the size of voxel.
M.S. Khan
M.S. Khan on 7 Sep 2020
i could not still figure out, how to measure the total number of voxels used. Please anyone can help me?

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