Extracting xyzpoints from Point Cloud

54 vues (au cours des 30 derniers jours)
Abdul Hannan Qureshi
Abdul Hannan Qureshi le 23 Avr 2022
Commenté : Naveed le 20 Avr 2024 à 20:33
I want to extract xyz points data from Point Cloud model.
pointCloud with properties:
Location: [14816040×3 single]
Count: 14816040
XLimits: [-122.5566 183.8412]
YLimits: [-214.3051 106.7991]
ZLimits: [-4.3266 6.3947]
Color: [14816040×3 uint8]
Normal: [14816040×3 single]
Intensity: []
I am using two provided ways but not getting any results.
1st Code
ptCloud = pcread('M.ply');
ptCloud;
xyzPoints = ptCloud.Location;
x = xyzPoints(:,:,1);
y = xyzPoints(:,:,2);
z = xyzPoints(:,:,3);
points3D = [x(:)'; y(:)', z(:)'];
ERROR
Index in position 3 exceeds array bounds. Index must not exceed 1.
Error in xyzextract (line 8)
y = xyzPoints(:,:,2);
2nd function is
ptCloud;
pts = rosReadXYZ(ptCloud)
ERROR
Error using rosReadXYZ
Expected input to be one of these types:
struct
Instead its type was pointCloud.
Error in rosReadXYZ (line 46)
validateattributes(msg,{'struct'},{'scalar'},'rosReadXYZ');
Error in xyzextract (line 13)
pts = rosReadXYZ(ptCloud,"PreserveStructureOnRead",true);
Kindly advise, I just want to extract xyz points from Point Cloud.

Réponse acceptée

Sean de Wolski
Sean de Wolski le 23 Avr 2022
The location is the xyz points and it's 2d, not 3d like how you're indexing it.
points3d = ptCloud.Location.';
Would give you what you're after.
  5 commentaires
Sean de Wolski
Sean de Wolski le 25 Avr 2022
You'd call it with
nrows = YOUR_DESIRED_ROWS
ncols = YOUR_DESIRED_COLS
pointcloud2image(ptCloud.Location(:,1), ptCloud.Location(:,2), ptCloud.Location(:,3), nrows, ncols)
Additionally, you could probably just call scatteredInterpolant directly.
Abdul Hannan Qureshi
Abdul Hannan Qureshi le 25 Avr 2022
@Sean de Wolski Thank you for clarrification. I will try that, I have clear preview now. Thanks again.

Connectez-vous pour commenter.

Plus de réponses (2)

Walter Roberson
Walter Roberson le 23 Avr 2022
Modifié(e) : Walter Roberson le 24 Avr 2022
Location: [14816040×3 single]
That tells you that the position information is 14816040 x 3 . It is not a 3D array.
Pointclouds store scattered information, not grids of information.
In some cases it may make sense to reshape() the scattered coordinates into a grid after it is extracted.
The information you get from the Location property is already the points3D array that you are trying to construct.
(Opps, Sean is right, you would need to take the transpose like he shows.)

Naveed
Naveed le 20 Avr 2024 à 8:57
Hi there!
How to access the features e.g (xyz, rgb values) in point cloud?
please help me out with this!
  4 commentaires
Walter Roberson
Walter Roberson le 20 Avr 2024 à 20:32
Are you getting an error message? If so, what is the error?
Note that rgb can come out empty if there is no RGB information stored in the point cloud.
Naveed
Naveed le 20 Avr 2024 à 20:33
clc;
clear all;
close all;
ptcloud = pcread("C:\Users\PMLS\Desktop\FYP\tape-ply.ply");
points = ptcloud.Location;
colors = ptcloud.Color;
disp(['Number of points: ', num2str(ptcloud.Count)]);
player = pcplayer(ptcloud.XLimits, ptcloud.YLimits, ptcloud.ZLimits);
view(player, ptcloud);
the output is: Number of points: 84062 but having no rgb values.
>>

Connectez-vous pour commenter.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by