Extracting specific data for multiple mat files

Hello. I am having around 1800 mat files that are the output of Venlodyne lidar. I have converted all of them to the PCD format as well. So, I want to extract the specific data, which is determined by specific row or column, from those files. Please help me with this question. Thank you so much for your support!

[Chunru]

Attach some sample data.

[Thanh]

Sorry for not adding files. Here are some files for instance.

Answer 1

[Chunru]

fn = dir("save*.mat")

fn = 2×1 struct array with fields:
    name
    folder
    date
    bytes
    isdir
    datenum

for i = 1:length(fn)
    matobj{i} = matfile(fn(i).name)
    matobj{i}.PCD  % Then you can access to any portion of data and assign the results to a variable
end

matobj = 1×1 cell array
    {1×1 matlab.io.MatFile}

ans = 
  pointCloud with properties:

     Location: [16×1808×3 double]
        Count: 28928
      XLimits: [-10.5304 19.9285]
      YLimits: [-5.1332 9.1553]
      ZLimits: [-2.5690 5.3415]
        Color: []
       Normal: []
    Intensity: [16×1808 uint8]

matobj = 1×2 cell array
    {1×1 matlab.io.MatFile}    {1×1 matlab.io.MatFile}

ans = 
  pointCloud with properties:

     Location: [16×1808×3 double]
        Count: 28928
      XLimits: [-10.5543 19.8885]
      YLimits: [-5.1543 9.2809]
      ZLimits: [-2.5587 5.3218]
        Color: []
       Normal: []
    Intensity: [16×1808 uint8]

Answer 2

[Thanh]

Thank you SIr for your answer. I tried to use the code to extract data of all mat files in column 1706 but it pops up another error "Index in position 2 exceeds array bounds. Index must not exceed 1." Can you help me with this error please? You can see my code adjustment here. Thank a lots!

fn = dir("save*.mat")
for i = 1:length(fn)
    matobj{i} = matfile(fn(i).name)
    dataPCD = matobj{i}.PCD  % Then you can access to any portion of data and assign the results to a variable
    Data = dataPCD(:,1706)
end

[Chunru]

What data you want to extract? dataPCD is an object of pointCloud. Which part of the data you want to extract?

pointCloud with properties:

     Location: [16×1808×3 double]
        Count: 28928
      XLimits: [-10.5304 19.9285]
      YLimits: [-5.1332 9.1553]
      ZLimits: [-2.5690 5.3415]
        Color: []
       Normal: []
    Intensity: [16×1808 uint8]

[Thanh]

I want to extract the y-value of column 1706 of Location data. I tried with the following code but the ouput is not as same as in Location data which I manually picked from those files.

fn = dir("save*.mat")
for i = 1:length(fn)
    matobj{i} = matfile(fn(i).name)
    dataPCD = matobj{i}.PCD  % Then you can access to any portion of data and assign the results to a variable
    Data(:,i) = dataPCD.Location(:,1706)
end

[Chunru]

The location data has the following 3D format:

Location: [16×1808×3 double]

Which slice of data you want to extract? You might want to specify 3 indeces instead of 2.

[Thanh]

Thank you Sir so much! I have extracted the data

[Chunru]

Glad to know that.