PCAP to .MAT (want to use PCAP in Examples)

i am currently using velodyne VLP16 and most of the work is done in PCAP file.

i have tried some matlab examples with PCAP file and they are really good but there are some examples that uses .mat file instead of pcap.

can any one help me in using PCAP in those examples or how can i convert PCAP to .mat or even how can i get .mat file using velodyne VLP16.

i am trying to use https://www.mathworks.com/help/driving/examples/ground-plane-and-obstacle-detection-using-lidar.html#driving-ex69316687

thanks,

[ismail ibrahim]

have you solved this problem.. cause i get the same problem as you do.. hope you can share how to solve it

[Abdullah Rasul]

v = velodyneFileReader('YOURFILE.pcap','SENSOR');

for i=1:100 % loop for how much frames we need to store in MAT file

ptCloud = readFrame(v,i)

ptInMatrix{i} = ptCloud;

end

ptInMAT = transpose(ptInMatrix);

save ptInMAT.mat

[ismail ibrahim]

thank you very much sir.. really appreciate your work

[Akshay Gupta]

Hello, can we save above mentioned converted MATLAB file into pcap file again?

As I have transfromed the point from pcap file frame by frame and save it in matrix/ or matlab file.

But I need to convert it to pcap file again.

Please suggest the solution for this.

Thanks

[Abdullah Rasul]

@Akshay Gupta

Matlab does not allow much processing with PCAP files. It usually converts them to .mat files for the processing.

In my opinion, convert your points to the point cloud file as explained here: https://www.mathworks.com/help/vision/ref/pointcloud.html#d123e118474

This way you can use the point cloud for processing as well and this point cloud format is compatible with most of the hardware/software

Thanks.

Answer 1

[Paola Donis Noriega]

Hi Abdullah,

You can read point clouds from a PCAP file and store them as an array of pointCloud objects. Then, you can save this array to a MAT file. For example:

% Create a reader object for the PCAP file.
veloReader = velodyneFileReader('lidarData_ConstructionRoad.pcap','HDL32E');

% Preallocate an array to hold each point cloud frame.
numFrames = veloReader.NumberOfFrames;
ptCloudArr = repmat(pointCloud(zeros(0, 3)),numFrames,1);

for i = 1:numFrames
    % Read each frame and store it in the array.
    ptCloudArr(i) = readFrame(veloReader,i);
end

% Save the array of point clouds to a MAT file.
save("velodyneData.mat","ptCloudArr") 

Note: MATLAB does not support writing point clouds to PCAP files. To export point clouds, you can use the pcwrite function to save each point cloud to a PLY or PCD file.