Point cloud coordinates vary greatly in different reference_frame

Software Python
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I used the zed2i camera to get the point cloud of the crane. The blue point coordinate value in the following figure is (1688726). When I set measure3D_ reference_ Frame to sl.REFERENCE_FRAME.CAMERA The point cloud coordinates obtained is (5.078392267227173, 0.7637787759304047, 16.464277267456055). When I set measure3D_ reference_ Frame to sl.REFERENCE_ FRAME.WORLD the point cloud coordinates obtained is (5.0526838302612305, -1.2955542206764221, 16.438910484313965). I use sl.COORDINATE_ SYSTEM.IMAGE coordinate systemThe difference between these two values is very large. What is the reason for this? In addition, I need to project the blue point to the ground. Which of the two modes is more appropriate?

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Hi @cao
Welcome to the Stereolabs community.

I see a bit of confusion in what you write, so I try to better explain those concepts.

The parameter coordinate_system of the structure InitParameters defines how the axis of the reference frame are orientated:

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The parameter measure3D_reference_frame of the structure RuntimeParameters defines where is the origin of the reference system defined by InitParameters.coordinate_system.
If the origin is REFERENCE_FRAME.CAMERA the coordinates of each point of the cloud is always referred to the center of the left camera sensor.
If the origin is REFERENCE_FRAME.WORLD the coordinates of each point of the cloud is always referred to the first position of the camera when the positional tracking module is started.

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Thank you for your reply. It seems that I made a mistake. Their values are equal.

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