Reading .ply file

Software Python
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1

Hello Everyone!
i want to understand the point cloud data generated by zed. and my saved .ply file looks like this

ply
format ascii 1.0
element vertex 1614755
property float x
property float y
property float z
property uchar red
property uchar green
property uchar blue
end_header
-1.911526 1.159542 -2.212860 149 145 136
-1.909242 1.159433 -2.212651 150 146 137
-1.906777 1.159213 -2.212233 149 146 139
-1.906022 1.160034 -2.213798 150 147 140 and so on…
i know i got this .ply file from depth image sized(1920*1080) generated by zed camera.
i want know after the end_header how the data is arranged? i want to compare this data with the depth image. where this -1.911526 1.159542 -2.212860 149 145 136 particular data is mapped in the depth image? is it top left corner? or center? and the Information in .ply belongs to which pixel in the depth image? is there any way to understand this data with depth image?
any help would be appreciated.
Thank you

2

Hello,
An easier way may be to compare your depth and point cloud data on runtime.
In your code,

  • the Depth will be a sl::Mat containing Z information of every pixel of the image.
  • the point cloud will be a sl::Mat containing X, Y and Z information on every pixel of the image.
    Basically, the depth information is included in the point cloud.

Antoine

3

Hi,
Can you take an example?For example,I hava a pixel of the image like(100,200).How can i get its 3d coordinate from point cloud?I use the function
point_cloud = sl.Mat(res.width, res.height, sl.MAT_TYPE.F32_C4, sl.MEM.CPU)
point_cloud.read(point_cloud_file)
But it is not correct.