How to slice a point cloud along z axis

Hi, i got the following question:

i have a crown tree point cloud and i need to slice along z axis with with 10 cm thickness. Finally, i need to calculate the volume by alpha shape algorithm for each individual slice.

How to solve these problem?

Thank you so much

Answer 1

[Paola Donis Noriega]

You can slice a point cloud along the z-axis as follows:

% Use the teapot point cloud as an example.
ptCloud = pcread('teapot.ply');

% Get the point cloud z limits.
minZ = ptCloud.ZLimits(1);
maxZ = ptCloud.ZLimits(2);

% Define the thickness of each slice.
thickness = 0.1;

% Use pcplayer to visualize the point cloud slices.
player = pcplayer(ptCloud.XLimits, ptCloud.YLimits, ptCloud.ZLimits);

% Use a for loop to select each point cloud slice.
for i = minZ:thickness:maxZ
    % Get the logical indices of the points in each slice.
    selectedIdx = ptCloud.Location(:, 3) >= i & ...
        ptCloud.Location(:, 3) < (i + thickness);

    % Select the point cloud slice using the indices.
    ptCloudSlice = select(ptCloud, selectedIdx);

    % Visualize the slice.
    view(player, ptCloudSlice)
    pause(0.2)
end

[stefano chiappini]

Thank you so much for your contribute. I will try your code next days.

I have appreciated your support.

[stefano chiappini]

Hi Paola, did you try your code with my dataset?

If yes, could you show me the ootput , please?

Thank you so much.

[Paola Donis Noriega]

Hi Stefano,

Yes, it works with your ply file. Here is an example of one of the slices.

[stefano chiappini]

Thank you so much. I have appreciated your support.

[Chen Xinzhuo]

Hi Stefano,

I also encountered the same problem recently.

I have tried but still don't know how to extract each point cloud slice.

I want to ask what method you use, please.

Thank you.