# How do I directly covert a depth image to 3-D point cloud?

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John Wray on 26 May 2016
Edited: DGM on 20 Feb 2023
Hi,
I could use pcfromkinect() function to convert depth data from kinect device into 3-D cloud points.
But how could I convert the depth matrix that had already extracted from kinect into 3-D cloud points ?
I mean, pcfromkinect() seems only works from device to 3d points cloud, not matrix to cloud.
jenny jenny on 15 Oct 2017
did you get the answer, because i have the same problem
Simon Cool on 23 Jan 2018
Moved: DGM on 20 Feb 2023
Same problem!

Marten J on 5 Nov 2018
I had the same problem. I could solve it through a double for-loop... but it's not the most efficient way:
if true
A = double(depthImage);
n=0;
[s1 s2] = size(A);
for i = 1:s1
for j = 1:s2
n = n+1;
Punkte(n,1) = i;
Punkte(n,2) = j;
Punkte(n,3) = A(i,j);
end
end
end
so I calculated the depthImage in the Pointcloud matrix [x-vector, y-vector, z-vector] but it takes some time.
Also only the Z-Value is in the metric system... the x and y- values stay in the Pixel system... to transform then in the Objekt-coordinate system you need the calibration and the Collinearity equations.

Preetham Manjunatha on 5 Oct 2022
This link can help to convert RGB-D images to point cloud, provided the camera intrinsic parameters.

Birju Patel on 17 Nov 2022
pcfromdepth has been added to Computer Vision Toolbox in R2022b: