Batch conversion from mat file to pcd file

Hello. I have around 1800 mat file in the discontinous order like 1,2,4,7,8, etc. I already found a code to load all the mat file but I can not do the batch conversion from mat to pcd file. Can anyone help me with this? Thanks in advance!

Answer 1

[Walter Roberson]

inputdir = 'Appropriate mat folder name goes here';
outputdir = 'Appropriate pcd folder name goes here';

if ~exist(inputdir, 'dir'); error('Input directory %s does not exist', inputdir); end
if ~exist(outputdir, 'dir'); mkdir(outputdir); end

dinfo = dir( fullfile(inputdir, '*.mat') );
filenames = fullfile({dinfo.folder}, {dinfo.name});

for K = 1 : length(filenames)
    thisfile = filenames{K};
    [~, basename, ~] = fileparts(thisfile);
    outname = fullfile(outputdir, [basename '.pcd']);
    Convert_mat_to_pcd(thisfile, outname);
end

Given appropriate code Convert_mat_to_pcd that uses the first parameter as the name of the input .mat file and uses the second parameter as the (fully qualified) output file name.

[Vu Minh]

Thank you for your suggestion. However, when I replace the inputdir and outputdir with my two appropriate directory, the code ran into an error stating that Unrecognized function or variable 'Convert_mat_to_pcd'. This means I have to define the function Convert_mat_to_pcd before running the code right. Sorry for this because Im a very beginner.

[Walter Roberson]

I have no idea how to convert your mat files to pcd files. I do not the variables you have stored, or which portion of them need to be extracted, or which computations need to be done to create something that could potentially be written to a pcd file. I have no idea what the pcd file format is, and I do not know if any routines are available to write to pcd files.

The difficulty you outlined was in how to loop through the input files. The implication was that given any one mat file that you already know how to convert it to pcd. If so then write that logic into your own function Convert_mat_to_pcd

[Walter Roberson]

https://www.mathworks.com/help/vision/ref/pcwrite.html can write pcd files

[Vu Minh]

Yes I can convert 1 by 1 mat file to pcd as the code below:

A = importdata('save_220523_103750_pointcloud.mat');

xyzPoints = A.Location;

ptCloud = pointCloud(xyzPoints);

pcwrite(ptCloud,'save_220523_103750_pointcloud.pcd');

[Walter Roberson]

function Convert_mat_to_pcd(matname, pcdname)
A = load(matname, 'Location'); 
xyzPoints = A.Location;
ptCloud = pointCloud(xyzPoints);
pcwrite(ptCloud, pcdname );
end

[Vu Minh]

Thank you sir for your valueable advice. I got this now. Anyway the function for loading mat file should be "importdata" instead of "load".

[Walter Roberson]

No, the function for loading mat files should be load(). importdata() has a lot of overhead and can return unexpected results.