How to stack .mat files?

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Chathu 2016-4-28

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评论： Chathu 2016-4-30

Suppose in one of my data set, i have 20 .mat files.

Now, i want to stack all 20 .mat files together.

The issue is though they are in the same data set, size of each .mat file differs (not a huge variation though). As my final objective is to create a 3D model, how can i stack those .mat files together in order to open in another visualization software? Kindly (atleast) send me a link/documentation which help me to resolve this issue.

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Answer 1

Walter Roberson 2016-4-28

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You cannot stack .m files. You might be able to stack variables that are stored in the files.

However, if the variables are not all the same size, you need to define how they are to align. Should they be rescaled (as if they are images of different resolution), or should the center all be in the same place and the smaller ones should be padded on all sides, or should the top left edge be aligned and the bottom right be padded on the smaller, or are these images containing features that have to be "registered" (lined up), or ... ?

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Walter Roberson 2016-4-28

在 MATLAB Online 中打开

dinfo = dir('*.mat');
data = [];
for K = 1 : length(dinfo)
  thisfile = dinfo(K).name;
  filestruct = load(thisfile);
    %replace the following with a direct access into filestruct if the variable name is fixed
    fn = fieldnames(filestruct);
    var_to_load = fn{1};
    thisvar = filestruct.(var_to_load);
    [dr, dc, ~] = size(data);
    [tr, tc] = size(thisvar);
    %padding might be asymmetric
    if dr < tr
      npad1 = floor((tr - dr)/2);
      npad2 = tr - dr - npad1;
      data = [zeros(npad1, dc); data; zeros(npad2, dc)];
      [dr, dc, ~] = size(data);
    elseif dr > tr
      npad1 = floor((dr - tr)/2);
      npad2 = dr - tr - npad1;
      thisvar = [zeros(npad1, tc); thisvar; zeros(npad2, tc)];
      [tr, tc, ~] = size(thisvar);
    end
    if dc < tc
      npad1 = floor((tc - dc)/2);
      npad2 = tc - dc - npad1;
      data = [zeros(dr, npad1), data, zeros(dr, npad2)];
      [dr, dc, ~] = size(data);
    elseif dr > tr
      npad1 = floor((dc - tc)/2);
      npad2 = dc - tc - npad1;
      thisvar = [zeros(tr, npad1), thisvar, zeros(tr, npad2)];
      [tr, tc, ~] = size(thisvar);
    end
    data(:,:,K) = thisvar;
  end

Chathu 2016-4-29

i am wondering why i am getting an error? (eg: Subscripted assignment dimension mismatch)

So its possible to stack the variable K now, is it? Thank you in advance.

Chathu 2016-4-30

i was able to get away with the error by commenting out the foll: data(:,:,K) = thisvar;

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