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Kate
Posts:
83
Registered:
8/28/10
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Re: gaussian convolution of XYZ data (code provided)
Posted:
Jan 10, 2013 8:23 AM
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help please
"Kate " <chino_tones@hotmail.com> wrote in message <kcleab$snu$1@newscl01ah.mathworks.com>...
> 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.
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