converted vtk files are not seen

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Chathu 2016-4-19

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/279810-converted-vtk-files-are-not-seen

评论： Chathu 2016-4-22

采纳的回答： Walter Roberson

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I was trying to convert my 3d mat files to .vtk format using the code showed inside the below link

http://www.mathworks.com/matlabcentral/fileexchange/23416-writetovtk

For example,i was first trying to convert one mat file to .vtk file. So before the code begins this is what i typed:

filename='P3290321.mat';
matrix=size('P3290321.mat');

Output: no errors , but nothing is written either.(i am certain this code works well when looking at the comments, but i don't know what mistake i am doing here)

I wonder what happened to my converted .vtk files? Can anyone kindly guide me to overcome this issue.

采纳的回答

Walter Roberson 2016-4-19

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https://ww2.mathworks.cn/matlabcentral/answers/279810-converted-vtk-files-are-not-seen#answer_218586

size('P3290321.mat') means to take size() of the string 'P3290321.mat' which is a 1 x 12 char array.

If you want to use data inside of P3290321.mat then you need to load() the file and access the appropriate loaded variable.

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Chathu 2016-4-20

编辑：Walter Roberson 2016-4-21

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Walter, First of all, you have been very helpful. Really admire it.

Second of all, With respect to the image P3290319.jpg: i calculated the calibration factor which is 0.0003 (mm). slice thickness is 2 (mm). Finally i did not get the above error(eg:Not a binary MAT-file) when loading the mat file because i added '-v7' to the code, as follows:

load ('P3290319.mat') % load the MAT file in the workspace
[x,y]=find(any(maskedRgbImage,3));
xyz = [x, y];
xyz(:,1) =xyz(:,1).*0.0003;
xyz(:,2) =xyz(:,2).*0.0003;
xyz(:,3) = 0.2;
save('P3290319.mat', 'xyz','-v7','-append')

Third of all, with respect to size(), you have asked to use string of 'P3290321.mat'. Did you mean,

filename=load('P3290319.mat');
str = mat2str(filename)
str=size(str);

But i am getting an error.

Error using mat2str (line 55)
Input matrix must be numeric.

Fourth of all, so let me send the full code then.

filename=load('P3290319.mat');
str = mat2str(filename);
str=size(str);
% Get the matrix dimensions.
[N M O] = size(matrix);
% Get the maximum value for the normalisation.
mx = max(matrix(:));
% Open the file.
fid = fopen(filename, 'w');
if fid == -1
    error('Cannot open file for writing.');
end
% New line.
nl = sprintf('\n'); % Stupid matlab doesn't interpret \n normally.
% Write the file header.
fwrite(fid, ['# vtk DataFile Version 2.0' nl 'Volume example' nl 'ASCII' nl ...
    'DATASET STRUCTURED_POINTS' nl 'DIMENSIONS ' ...
    num2str(N) ' ' num2str(M) ' ' num2str(O) nl 'ASPECT_RATIO 1 1 1' nl ...
    'ORIGIN 0 0 0' nl 'POINT_DATA ' ...
    num2str(N*M*O) nl 'SCALARS volume_scalars char 1' nl 'LOOKUP_TABLE default' nl]);
for z = 1:O
    % Get this layer.
    v = matrix(:, :, z);
    % Scale it. This assumes there are no negative numbers. I'm not sure
    % this is actually necessary.
    v = round(100 .* v(:) ./ mx);
    % Write the values as text numbers.
    fwrite(fid, num2str(v'));
    % Newline.
    fwrite(fid, nl);
   % Display progress.
      disp([num2str(round(100*z/O)) '%']);
  end
% Close the file.
fclose(fid);
end