Date: Jan 9, 2013 10:59 PM
Author: Kate
Subject: gaussian convolution of XYZ data (code provided)
Good day everyone,

I have a dataset of XYZ points. I then convert the dataset to a voxelized model.

Here is the data of the XYZ points and the code showing the relating voxels for this data (NOTE: I use a function called "VOXEL_IMAGE" you an download at: http://www.mathworks.com/matlabcentral/fileexchange/30374-voxel-image

%-------------begin---------------------------

data=[0 0.33333 0.5

0.18182 0.44444 0.625

0 0.66667 0

0 0.22222 0.125

0.27273 0.66667 0.25

0.36364 0.44444 0.4375

0.27273 0 0.625

0.54545 0.55556 0.75

0.54545 0.22222 0.875

1 1 1]

% for i=1:size(data,1)

% varargout = voxel(data(i,:));

% end

color = 'y';

alpha = 1;

edgec = 'k';

vs = 0.05;

voxel_image(data, vs, color, alpha, edgec);

%---------------------end---------------------------------

Now, I want to apply a 3D Gaussian Filter to convolute with this 3D voxel data. The voxelized model is represented as:

M(x,y,z)

So I want to convolute as follows using the 3d gaussian, G(x,y,z,sigma ):

M(x,y,z)*G(x,y,z,sigma) ;% where * represents the convolution

So, I created my own 3D Gaussian function. Here is the 3DGaussian filter:

%----------------------------

function f=gaussian3d(sigma)

% N is grid size set as 7, sigma speaks for itself

N =7;

[x y z]=meshgrid(round(-N/2):round(N/2), round(-N/2):round(N/2), round(-N/2):round(N/2));

f=(1/(sqrt(2*pi)*sigma)^3)*exp(-x.^2/(2*sigma^2)-y.^2/(2*sigma^2)-z.^2/(2*sigma^2));

%----------------------------

I have no issues with the function or anything, my problem is that my gaussian3d filter is essentially a 3D array, whereas my Data is just a single XYZ matrix, and I do not know how to go about doing the 3d convolution. This is what I have so far.

Any help would be appreciated.

cheers.