How to segment a point cloud along axis

I have a point cloud in .ply format. I want to segment and export a certain number of slices along Z axis.

How can i gain this output?

thank you so much.

Answer 1

[Adam Danz]

> I want to segment and export a certain number of slices along Z axis

The following two demos use the attached file teatpotOut.ply which is within a zip file since we cannot attach ply files. The two demos show two different interpretations of the question.

Interpretation 1: segmenting specific z-values

Read-in the ply file

teapotOut.ply = unzip('teapotOut.zip');
ptCloud = pcread('teapotOut.ply');

List z-values of interest

This demo selects every 500-th unique z-value resulting in 11 z-values.

zUnq = unique(ptCloud.Location(:,3));
nzUnq = numel(zUnq); 
zSlices = zUnq(1:500:nzUnq);

Extract all point coordinates that belong to the selected z-values

zIdx = ismember(ptCloud.Location(:,3),zSlices);
ptCloudSegmented = ptCloud.Location(zIdx,:); 

Plot results

figure()
pcshow(ptCloudSegmented)

Interpretation 2: segmenting a range of z-values

Read-in the ply file

teapotOut.ply = unzip('teapotOut.zip');
ptCloud = pcread('teapotOut.ply');

List a range of z-values to include in extraction

This demo selects all z-values between 0.8-1.2, inclusive.

zLim = [0.8,1.2];

Extract all point coordinates that belong to the selected z-values

zIdx = ptCloud.Location(:,3)>=zLim(1) & ptCloud.Location(:,3)<=zLim(2); 
ptCloudSegmented = ptCloud.Location(zIdx,:); 

Plot results

figure()
pcshow(ptCloudSegmented)

[stefano Chiappini]

thank you so much for you quick answer. Now i will try your tip.

[Adam Danz]

...any luck?

[stefano Chiappini]

i have to try your tip yet. As soon as i will have some score, i will inform you. Thank you very much.